By Dave McCracken

Suction mining underwater without a “dredge!”

Dave Mack

Important note: Since writing this article, over the period of a year,  the State of California has adopted new regulations which no longer allow any type of vacuum or suction to excavate material off the bottom of a waterway.  Therefore, the underwater suction gravel transfer systems outlined here will no longer be allowed until we overcome the suction dredge moratorium.  It is for this reason, we have now switched over to underwater blow mining.

Let me begin this by informing you that I am not a licensed attorney. Therefore, I am prohibited by law from providing legal advice. So the material here should just be taken as my own opinion based upon the factual material which I will present to you.  You guys are free to form your own opinions and take responsibility for your own actions.  Having said that, I will also inform you that our attorney has reviewed the following explanation and agrees that government officials are bound by the very language that they enforce upon us – and that my reasoning here is sound.

This discussion began on our Internet Forum where I announced that we have recently acquired the richest dredging claim along the Klamath River near Happy Camp, which will also provide some fantastic surface and underwater crevicing opportunities because of the gentle slope of exposed bedrock which is extending off the side of the river where the gold path is located.

We have actually acquired several very rich properties, but I will save that for the coming newsletters.

In my announcement, I pointed out that there is nothing in California’s dredging moratorium that prevents us from crevicing underwater using a motorized hookah air system, or even using a water pressure system to help blow gravel out of cracks.  The question I posed to our forum members is how to get the gold up and into a catch container without using a suction dredge.

It would be one thing if we were just uncovering an occasional gold nugget or two.  We would simply free those up with some hand tools and pick them out with a set of tweezers.  But I have seen crevices on this particular mining claim that were loaded with a zillion pieces of gold, much of it in fines and flakes.  You pretty much have to suck that up, or you will be there all year with a pair of tweezers! The original claim owners were recovering six and seven-ounce days (sometimes more) in places along this claim.  They were only in there a few years before they retired.  Since they operated an 8-inch dredge, they remained on the lower, slower portion of the claim.  There is at least a half-mile stretch of faster, shallower water on the upper portion of the claim that, to my knowledge, has never even been sampled.  This is the area I believe will make for good above and below water crevicing.

In response to my question, one of our more informed members sent me a copy of the California Department of Fish & Game’s (DFG) current suction dredge regulations which clearly state that “A person is suction dredging as defined when all of the following components are working together: (A) a hose which vacuums sediment from a river stream or lake; and (B) A motorized pump; and (C) A sluice box.” The regulations further state, “Every person who operates the suction nozzle of any suction dredge shall have a suction dredge permit in his or her immediate possession.” These regulations are current now, having been formally adopted in California on April 27, 2012.

The existing moratorium in California prevents DFG from issuing suction dredge permits.  We are strenuously challenging the moratorium in several jurisdictions.  Until our challenges are resolved, it is unlikely that we can operate suction dredges as defined by the regulations without being cited.  Since most of us don’t want to be in trouble with the authorities, we have been doing our dredging in southern Oregon for the past few seasons.

Suction Gravel Transfer image 1

But looking closer at the California regulations, there does remain a way for us to go down on the bottom of California’s waterways and suction up the shallower, higher-grade gravels.  This is because, as defined by DFG’s own formal regulations, as long as we remove the sluice box from our motorized suction system, we are not operating a “suction dredge.”  Said another way, there is an opportunity to use a motorized suction system to transfer high-grade gravel from one place in the river or creek to another location where the gravel can be more-easily processed in a separate system.

I am in possession of written communication from a high ranking DFG official, the very person who was in charge of developing the current regulations, which acknowledges that underwater suction-powered gravel transfer would not be considered “suction dredging” as long as the sluice box is removed from the system.  He also cautioned that there are water quality concerns and also streambed alteration considerations.  So there would be some limits involved.  I’ll discuss these more in a minute.

For now, let’s just get back to my original discussion about using a hookah and motorized pumping system to expose and recover gold from very shallow deposits out in the river.  I’m not talking about shallow water. I am talking about shallow material on top of underwater gold deposits.

Here is just one of several ideas:  Please see Figure A above. If I completely remove the sluice box from my 5-inch dredge, I am left with a floatation system which supports twin 6.5 HP Honda motors and pumps with a hookah compressor.  I could use a single motor & pump with compressor to power a 3-inch Hydro-Force nozzle jet.  This special nozzle will allow me the option to blow off lighter gravel to expose cobbles, which I can then move out of the way by hand.  This will allow me to work my way down to the pay-dirt without having to suck up any gravel.  Once I expose the pay-dirt, the Hydro-Force nozzle will allow me to suck it up and transfer it over to a catch container in shallower, slower water which is closer to the bank.  Or for that matter, I could just drop it in a small pile in the shallower water along the edge of the river.

If there is some distance involved between where I am prospecting and my catch container, I can use my second engine & pump to provide power to a booster jet attached to a second 3-inch hose (See Figure B).  Since the whole suction system would be underwater, I’m guessing that would give me a reach of fifty feet or more.

Suction Gravel Transfer System image 2

The catch container would need to be large enough to accumulate the amount of pay-dirt that I would suck up on a single dive. My suggestion would be to fabricate a baffle on the feed into the container so the material would be deposited there neatly.

If you make smart use of the blower function on the Hydro-Force nozzle, you can really minimize the amount of gravel that you transfer by suction to the catch container; perhaps so little that you could work it all down and recover your gold between dives with just a classification screen and gold pan!

If there is more non-gold bearing material present than you can blow off with the Hydro-Force nozzle, you would always have the option of sucking that off separately and depositing it outside of your catch container.

Several experienced prospectors I have spoken to about this had other ideas.  One suggested fabricating the catch container between the pontoons on his floating platform.  Then he could just float it over closer to the bank to pan the material after each dive.  Another who has already experimented with the idea says he successfully attached a 20-foot piece of PVC plastic tubing to direct the discharge into a catch container that was sitting up on the streambank.  This took place in the fall of 2012.  He was visited by local game wardens while doing the activity.  And while they expressed reservations (“sure looks like a dredge”), he was not cited and the wardens did not return.

While I’m sure we will learn more as we gain experience, here are a few of my own thoughts on “underwater suction gravel transfer systems:”

1)      Make certain to not have the sluice box from your original “suction dredge” anywhere in the vicinity of the program.  DFG regulations prevent you from having a “dredge” within 100 yards of any active waterway.  Therefore, that third component (sluice) should not be sitting up on the streambank or even in the back of your pickup truck, even if you are not using it.  Leave it at home!

2)      Do not direct the discharge of your suction system into some other type of recovery system that uses a sluice.  Using any sluice in combination with the suction system, all working at the same time, would likely meet the definition of a “dredge” in the regulations.

3)      There has been some suggestion that even sluicing the recovered gravels at some later time would fulfill the definition of a dredge.  You guys can make your own decisions about this, but I’m not buying the theory.  The language in the regulation defines the three components working together.  So it would seem reasonable that you could shut your underwater suction transfer system down and then separately process the gravel in any normal way that does not violate water quality standards.  Though I would not be using the sluice that I took off my suction dredge, or any sluice which could be attached to the suction system. Be advised, though, that as soon as you have any sluice as part of your program within 100 yards of the suction system, you will be on thinner ground. Personally, I am inclined to be careful about sucking up a lower volume of only the highest-grade material and use a gold pan to work that down between dives (more on this below).

4)      I would not suck a bunch of silty material into a catch container that is sitting in dead water alongside the bank.  That might provoke water quality concerns.  This is why I suggest using the blowing option on the Hydro-Force nozzle to first free up material out under the moving water. Gold is heavy.  It won’t blow away if you pay attention to what you are doing.

5)      I also would not advise using this system to make large excavations out in the creek or river.  That might provoke streambed alteration concerns.  I would use this method to work shallow deposits much the way we do in high-banking.  Having said that, it has also been pointed out that the existing suction dredge regulations clearly state that there would be no requirement for a stream alteration permit, and there would be no deleterious impact upon fish, from the use of 4-inch suction dredges in California’s waterways.  So it would be pretty unreasonable for DFG to make a stream alteration argument if you are careful about not making large excavations.

6)      I would advise the use of riged pressure hose between the pump and nozzle jet on this type of system.  It is difficult enough to keep the kinks out of lay flat pressure hose outside of the waterway.

7)      Since initially, DFG wardens may not be aware of their own formal definition of a “dredge,” I suggest you print out at least the first page or two of the regulations which include the formal definition of a “dredge,” and have them available if and when any officials come around to see what you are up to.  Make sure to point out the complete absence of a sluice on your suction system. And whatever you do, never refer to this activity as “dredging.”  Because it is not dredging!  It is an underwater suction system used to direct small volumes of high-grade material into a catch container.  Nothing more.  If you tell the warden you are “dredging without a sluice box,” you will probably provoke a citation, the warden telling you to explain it to the judge!

8)      If any citations are written for this non-dredging underwater form of prospecting, please get in touch with us without delay.  We will likely want to become involved with your defense.

Conclusion:  I can process material through a “suction dredge” about as fast as anyone I know.  Yet, my tailings don’t amount to much at the end of my dives.  This is because most of the underwater work has to do with freeing and moving oversized material out of the way (rocks that are too big to suck up).  Depending upon the size of the suction nozzle, perhaps as much as 95% or more of the volume has to do with rolling rocks behind me.  I would normally suck up the other 5% of material into my sluice box if I were “dredging.”  That volume over my sluice box gives me a substantial amount of heavy concentrates to process – which takes quite a bit of time.

But with this underwater gravel transfer system, I can easily visualize how I can blow the lighter material out of my way and only suck up the pay-dirt.  This would dramatically reduce the amount of material I will need to process out of my catch container.  While the underwater process may not be as fast or efficient as “dredging,” I might make up for it by having fewer concentrates to process.

Please note my words in bold just above.  They are perhaps the most important words I have said here.  This is because if you suck everything into your catch container, it will soon fill up with low-grade material which may not be worth the time to process further!  The whole idea in this new system is to get the low-grade material out of your way, and only suck up the very small volume which is directly associated with the gold deposit.  Gold deposits are nearly always located in a contact zone.  This means either on the bedrock, between storm layers, or on top of the upper layer of hard-pack.  There is an entire education about this in the articles at this link. If you still need help understanding this, you should attend one of our weekend group mining projects and allow us to show you exactly what you are looking for!

Using this system to discriminate carefully about what you suck up will accomplish two important objectives:

A)    You won’t find yourself up on the bank most of the day panning a bunch of gravel that doesn’t have much gold in it.

B)    You will only use the suction system to recover a very small volume of material – only that which contains the gold.  A small volume tool to help with your crevicing program will give our enemies less to complain about.

I thought you guys might be interested in an official position. There has been quite a lot of debate about this “underwater suction gravel transfer” idea on the GPAA forum since I have gone public with it; and finally, someone asked Mark Stopher of DFG for the straight scoop:

Here are the official answers (2 January 2013):
“I carefully read (today) the information that McCracken provides on his website. I believe Dave McCracken’s description of the legal requirements and application of the regulations is accurate. If practiced as he describes, this is not a violation of the moratorium and is not prohibited.

There is no specific permit required and no seasonal restrictions. Since this is not suction dredging, neither the moratorium or our adopted regulations for suction dredging apply. It’s essentially a loophole in existing law. However, as McCracken notes, Fish and Game Code section 1602 could apply if the streambed alteration is substantial, that is, you create a big hole. My guess is that such a system will be less efficient, and less excavation will occur, than if you were using a suction dredge since there is no sluice box and miners will need to use some other system to sort through the material.”

Mark Stopher
Habitat Conservation Program Manager
California Department of Fish and Game
601 Locust Street
Redding, CA 96001

voice 530.225.2275
fax 530.225.2391
cell 530.945.1344

Underwater Mining Seasons on New 49’er Properties:  Underwater suction mining without the use of a “dredge” is allowed  on our Klamath River properties between the Scott and Salmon Rivers on a year-round basis, and up the Klamath from its confluence with the Scott from the 4th Saturday in May through September 30.  Underwater suction mining is permitted along our creek properties and the Scott River from July 1 to September 30. Underwater suction mining is permitted on the Salmon River from July 1 through  September 15.

This new idea will at least allow us access to some of the submerged gold deposits that otherwise would be out of our reach until the “dredge” moratorium is lifted in California.  How’s that for good news?

 

New 49'er Newsletter

SECOND  QUARTER, MAY 2012                                VOLUME 26, NUMBER 5

  Happy smiles Running high-banker

Successful gold mining on any scale must be accomplished in two separate steps.  The first is prospecting. We also call this sampling.”  We sample to try and find a high-grade deposit.  The idea is to not invest very much of your time into any given location until you find something that is going to pay off.  Once we find a good location through sampling, we switch gears into what we like to call “production.”  During the production phase, we try and process as much of the high-grade material as possible given our rather limited resources.

Nearly the entire focus of our Weekend Group Projects is on these two phases.  And it was no different on this particular project.  After reviewing the theory Saturday morning using a backboard demonstration, all 48 of us met after lunch out at our famous K-15A property, otherwise known as the “Mega-hole.”  While the theory is important, nothing can compare to actually doing it out along the river with experienced prospectors.

Once out on the river, the first thing we always do is provide a substantial demonstration on how to take a proper sample.  Sampling is not just about shoveling some streambed material in your pan.  You have to focus on gathering up targeted material.  Since we know that the gold on K-15A is concentrated directly on top of a special brown layer which is about a foot deep in the streambed, the best sample will be from filling our gold pan with that particular material.  We do this by first shoveling aside the material which is on top.  Once we get down to the target area, we carefully gather up the material which is in the contact zone between the two different layers.

Then we pan that material very carefully.  We need to be careful, because the sample is so small.  We cannot afford to lose a single speck of gold if we want to have an accurate look at how much gold is in the contact zone.  Sometimes a sample pan will just turn up a few specks.  Seeing those specks might prompt you to take a few more samples.  Then one of those additional samples might show a better result.  The better result might prompt you to process 25 or 50 buckets of the target material through your high-banker to see how good the area really is.  This is how high-grade deposits are found.

 Sample result Showing gold

After providing this group with a sampling and panning demonstration, we passed the pan around to show how much gold we recovered.  It was better than an average result.  Doing this provides newcomers a baseline in two important ways:

1)      They can compare how much gold they get in their own pan samples to what they saw me recover.  Then they have an idea if they are getting an acceptable result.

2)      They will be able to compare how much gold we get in our single sample pans to the amount of gold we recover when processing the same material in volume on the following day.  Tying the sample result to the production result gives a prospector judgment in what he or she is looking for during prospecting.

After seeing my result, this enthusiastic group spread out across the bar and started doing their own pan samples. Thankfully, I had eight experienced members helping me with this particular project.  While half of them were helping beginners with their panning techniques, the others set up our high-bankers for the following day. A “high-banker” is a gold recovery system which can be set up some distance from the waterway, which will process much more volume than a gold pan. This means pay-dirt does not have to be carried very far, or can actually be shoveled directly into the high-banker.

About half of the participants in this project were beginners.  So my helpers and I stayed out on the bar on Saturday afternoon until everyone out there was panning correctly.  Since many were recovering their first gold, which was theirs to keep, there were still plenty of people going hard at it when we departed.

Saturday night potluck at the Grange Hall in Happy Camp lured in most of the participants, along with plenty of other members who either live in the area or were doing their own mining programs.  There was more food to go around than we needed, and morale was very high – which always makes me happy.  We had a short meeting and ended with a prize drawing.  These weekly potlucks have been a New 49’er tradition during our busy months all the way back to our first season in 1986.

We were shifting over into a production mode on Sunday. So my helpers put their “Team Leader” hats on and split the whole bunch of people down into smaller, more efficient groups.  We started early, about 7 o’clock, so we could get most of the hard work done before the worst heat of the day was upon us.

 Connie People digging

All of the gold we recover on Sunday goes into a common bucket.  Everybody who helps will get an equal share at the end of the day.  The production focus on Sunday switches to volume of the target material.  We want to fill buckets with as much pay-dirt as we can, and process it through the high-bankers.  Having said this, there are three important points that we stress:

1)      Processing volume is most-effectively accomplished by reaching way out and dragging a bunch of material into the hole.  We call this a “top cut.”  Once in the hole, it is easy to remove oversized rocks from the loose material and shovel the remainder into buckets. Then we do the same thing again with a “mid cut.” The wider you are making the top cut, the easier it is to take apart the puzzle of rocks that are wedged together.  This method is much faster than just working one rock loose at a time, a practice we refer to as “nitpicking.” Here are some demonstrations from me of how to use a hand-pick to get optimum results:

 

 Richard, 2 buckets Three guys

2)      It is important to not fill the buckets with low-grade material.  By this, I mean loose sand or gravel on the surface seldom have enough gold to justify being processed through a high-banker.  But because beginners want to feel productive, sometimes we really have to impress upon them to stop filling buckets with non-producing material.  Since we will be feeding the high-bankers at full capacity, every bucket of worthless material will subtract from a bucket of pay-dirt.  This will directly affect how much gold we will recover at the end of the day.  The same principle applies to the material which is below the contact zone.  The amount of gold we will recover is directly related to how much of the target material that we process. Here is Ray Derrick’s explanation of the way we like to do it:

Feeding high-banker

3)      To get the most out of a high-banker recovery system, you must supply it with a steady feed.  Dumping a whole bucket in there at once will overwhelm the system, and some of your gold will wash right out into the tailings.  You can tell where maximum capacity is by watching to make sure the riffles do not get overwhelmed and pack up. Here follows Richard Krimm’s explanation of the proper way to feed a recovery system:

We normally do not break for lunch on Sunday.  It is understood that everyone will take breaks whenever they need them.  Otherwise, we just try to keep the high-bankers running.  When they run out of fuel, it gives us an opportunity to clean out a front portion of the recovery system from one of the high-bankers.  We work this down in a pan and show the gold around to all the participants.  This goes a long way to convince everyone that their effort is adding up to something good.  It also always motivates another 150 or 200 buckets of pay-dirt after we refuel.  The following video segment captured the mid-day look at how we were doing:

Pan of goldIt starts getting pretty hot out on the bar by about noon.  So that’s normally about the time we are shutting things down and going into our final clean-up stages.  By clean-up,” I mean removing the gold and other heavy concentrated material, mostly iron, from the recovery system, and going through a step-by-step process to reduce it all the way down to just the gold.  We begin this process out on the bar; but the final part, and the gold split is completed in Happy Camp.

The main purpose of these Weekend Projects is to expose our members to all of the essential parts of a successful small-scale gold mining program.  It begins with sampling. Then it switches to production. And then we go through the final clean-up, separation, weighing and gold split.  All participants are invited to participate in every step.

In all, we recovered 285.5 grains of beautiful gold. That’s about 6/10ths of an ounce, or about $1000 at today’s gold value.  Not too bad for less than four hours of production work.  There were also 23 natural gold nuggets.  There were a lot of smiling faces as we split the gold evenly amongst the participants.

Final gold

High-banking in California this Season

While Oregon is more user-friendly towards suction dredging; our best high-banking opportunities remain along our extensive properties on the Klamath River in northern California.  Therefore, Our Weekend Group Mining Projects will take place during 2012 near our headquarters in Happy Camp.  They are scheduled as follows: June 2 & 3; June 23 & 24; July 14 & 15; August 4 & 5; August 25 & 26. These events are free to all active Members, and everyone is invited to attend.  Please contact our office in advance to let us know you will be there: (530) 493-2012.

New Legal Fund Prize Drawing

On behalf of The New 49’ers and some individual members, our attorney filed a legal challenge to California’s new dredge regulations last month in concert with a “takings” claim against the State of California. If we cannot overcome the incredibly-restrictive regulations, then we will force the State to buy all of the mining properties which have been rendered valueless. Defending the rights of small-scale miners, this now places us in three separate litigations, in three separate jurisdictions. Since costs are mounting, we greatly appreciate your participation in our legal fund drawings!! 

Gold Eagle Coins

We will be giving away 15 prizes in our new legal-fund raiser:

Grand Prize: 1-ounce American Gold Eagle
Four ¼-ounce American Gold Eagles
Ten 1/10th-ounce American Gold Eagles

The drawing will take place at our weekly potluck in Happy Camp on Saturday, 7 July (2012).

The girls in our office automatically generate a ticket in your name for every $10 legal contribution that we receive ($100 would generate 10 tickets, etc).  There is no limit to the size or frequency of your contributions, or to the number of prizes you can win. Contributions can be called in to our office at (530) 493-2012, or they can be mailed to The New 49’ers, P.O. Box47, Happy Camp, CA 96039.  Or you can do it on our web site by going here:  Make a Donation

2012 Group Insurance Policy

All Members are eligible to sign up for $10,000 of accidental medical Insurance which covers you while camping, prospecting for gold, and also during any activities which we sponsor. Dental accidents are included, along with $2,500 for accidental death or dismemberment.  The policy has a $100 deductable.  It is an annual policy which extends through January of 2013.  This insurance is available for $30 per year, per person. More information can be found here.

Sign up for the Free Internet Version of this Newsletter: We strongly encourage you to sign up for the free on line version of this newsletter.  The Internet version is better, because you can immediately click directly to many of the subjects which we discuss; because the on line version is in full color; because we link you directly to locations through GPS and Google Earth technology; and because you can watch the free video segments which we incorporate into our stories.

 

The New 49’ers Prospecting Association, 27 Davis Road, Happy Camp, California 96039 (530) 493-2012
www.goldgold.com

 

New 49'er Newsletter

SECOND  QUARTER, APRIL 2012                                VOLUME 26, NUMBER 4

Clean UpDiggers

I have been managing these weekend group mining projects for the past 26 years. All this experience has taught me that every single group has its own chemistry.  There are probably a lot of different things that contribute to this; the different personalities, the weather, how the bigger world is doing at the moment, and perhaps even how I am feeling.  But every group is different.

We always begin with a morning of theory on Saturday.  This gives me an opportunity to size up the participants and the group-chemistry, organize things with my experienced helpers and provide a presentation of the long-proven procedures that we have developed to find gold.  We call this a  sampling plan.

These days, we do the initial meeting and the morning presentation at the Grange Hall in Happy Camp.  Nearly everyone was already present there when I showed up at about 9 AM.  And I knew even before I got out of my car that this was going to be a lively bunch.  They were already having a lot of fun.  This is all good; because my seasoned helpers and I know how to direct all that enthusiasm into the hard work which would be necessary later in the day, and especially on Sunday.

After going over the weekend plans and covering the theory on sampling, I always take time to answer everyone’s questions before we break for lunch.  But this time, I had to cut it short with this lively group or we would not have had time for lunch!  I know the participants are really into it when they are asking all the right questions.

DiggingRich Krimm

Saturday afternoon found us all up at k-15A, otherwise known as the Mega Hole.  This is one of our more popular high-banking areas.  By high-banking, I am talking about mining up out of the water.  We also have a very popular camping area at K-15A.  This makes it convenient for participants to just walk down to the gravel bar where we are doing the project.  K-15A is quite a long mining property.  Over the many years, we have done plenty of weekend and week-long mining projects there, on both sides of the river.  The property has been very productive for us, and we are lucky to have it.

On this particular project, we were up towards the upper-end of the property.  We have been doing these weekend events there, because boats are not required when we have larger groups, and because there is this very distinct brown layer which is usually only a about a foot deep into the gravel bar.  We get lots of nice gold right off the top of that layer!

I am lucky to have a bunch of experienced members who enjoy coming out and helping me to organize these events.  With their help, we split the larger group into smaller ones, each with one of my helpers as a team leader.  The team leaders went out and did some sampling in advance on Saturday morning, while the rest of us were still busy at the Grange Hall.  So, when we showed up out on the gravel bar on Saturday afternoon, my helpers just pointed to several hot-spots where I could provide a sampling and gold panning demonstration.  It’s always better if I turn up some gold in the sample.  This gets everyone motivated to find more gold!

Participants get to keep any gold they find on Saturday afternoon. So after seeing the gold from my sample, this group went right to work.  It wasn’t long before people started showing me the gold in their pans.  For many, these weekend projects provide the first gold they ever found.  “First gold” is always the most precious!  I still remember my first gold. It didn’t come this easy!  But it was still a very magic moment. So I enjoy this part as it unfolds, sharing the “first gold” moments with others, watching for the sparkle in their eye at the first moment of realization.  I love my job!

 RestingUSA Scarf

Really, we were just going through the motions out there on Saturday afternoon.  My helpers had already confirmed where we were going to dig on Sunday.  So we devoted the afternoon assisting beginners to dial in their gold panning techniques. It’s not that panning is difficult.  It just takes a little practice to teach your body the correct motions.  This bunch was catching on fast!

As the afternoon progressed, we set up the high-bankers close to the places where we would dig pay-dirt.  We wanted everything to be ready for an early start on Sunday morning.  This is because we like to get most of the physical work done before the summer heat of the day sets in.

A high-banker is a portable sluicing device, like an aluminum trough with baffles (called riffles) along the bottom edge. Since gold is 5-to-6 times heavier than normal gravel and sand, it gets trapped in the riffles, while the lighter material is washed through by water. Because water is pumped to it, the recovery system of a high-banker can be set up close to the dig-site.  This eliminates the need to pack the pay-dirt closer to water.

After getting everything set up, my helpers and I left to go get set up for the evening meal.  There were a bunch of participants lagging behind out there still panning for gold.  Some of them probably stayed until dark!

Nearly everyone met up back at the Grange Hall that evening to participate in our Saturday evening pot-luck.  These pot-lucks are a tradition that dates all the way back to 1986 when we started The New 49’ers.  Mostly, they are just get-togethers.  Lots of members come.  We have a great meal, enjoy each other’s company, exchange helpful information and do a prize drawing.  Mostly we just have a good time.

Workers High-banker

Almost everyone was out on the bar ahead of me on Sunday morning.  The team leaders had everyone organized, and Rich Krimm informed me that two or three hundred buckets of pay-dirt had already been processed.  This was good!  Man, there was a lot of productive activity going on.  The enthusiasm was infectious. I’m not sure I have ever seen so many people having so much fun playing in the dirt! Here are some explanations of what was going on:

Since most of the work gets done before lunch on Sunday, we just encouraged the flow of material from off the top of that brown layer, into buckets, and through the high-bankers.  The harmonious sound of picks, shovels, rocks being tossed out of the way and material being poured into the high-bankers is like music to my ears.  There was a lot of laughing and joking going around.  Morale was high out there.  This always makes me feel good!

We don’t normally shut things down for lunch on Sunday.  People just take breaks when they are ready.  We usually only stop when the water pumps run out of fuel.  This also gives us an opportunity to clean-up one of the high-grade portions a one of the high-bankers.  A “high-grader” is a smaller portion of the high-banker that recovers perhaps about 50 percent of the gold.  Because it can be cleaned up fast, you can get a good idea how an area is producing when you run production samples.  A few hundred buckets is a pretty substantial sample! 

Nuggets Onlookers3

Rich made quick work of recovering the gold from one of the high-graders. Then he made sure to take it around and show everyone out there on the work site.  You would have thought we were at a sports event the way everyone was cheering.  The hard work was really paying off!  

We actually do this on every project so everyone can see how their physical energy is being converted into Mother Nature’s most-favored treasure – gold!  This always motivates at least another few hundred buckets once the pumps get fueled up.  But on this day, the group never stopped filling buckets even while we were preparing for a second run.  They only stopped digging when they saw that others were cheering over the gold! The following video sequence captured how jacked up this bunch was: 

So that we can be completely finished by dinnertime on Sunday, with everything put away and the gold split up, we like to end off on the dig by about noon.  This was a real struggle with this group, because they just wanted to keep digging.  I imagine some of them would still be out there digging if we didn’t shut the high-bankers down!

Le Trap Onlookers

After cleaning out the high-banker recovery systems, we ran the concentrated material over a special “Le-Trap” sluice that we use to reduce the amount of iron with no loss of gold.  It is always a treat to watch the gold accumulate in the riffles.  Some of the participants were wondering where the ice cold beer was!  But that would have to come later, since we were not yet finished with our day.  Here are two video sequences which captured a Le Trap demonstration, and also the fun we were having during clean-up:

After back-filling the holes we had dug out on the bar, we made plans to meet back up at the Grange Hall where we would finish the clean-up and split the gold.

Let me just say that this is real mining.  The participants get to assist in every step along the way.  In addition to being part of the process, the experience rubs off on all the participants, allowing everyone the knowledge to do it on their own.  I demonstrate the process exactly how I do it in my own mining programs.

Final gold Onlookers2

Once we got it all separated and cleaned up, our work from several hours of hard work that morning produced 290 grains of gold, which is 6/10ths of an ounce.  That’s around a thousand dollars, and it would have bought us plenty of beer.  And pizza, too!  There were also 21 nuggets, the largest being 6 grains.  We split it all up evenly between the 43 participants, and I’m not sure I have ever seen a happier bunch of people!

High-banking in California this Season

While Oregon is more user-friendly towards suction dredging; our best high-banking opportunities remain along our extensive properties on the Klamath River in northern California.  Therefore, Our Weekend Group Mining Projects will take place during 2012 near our headquarters in Happy Camp.  They are scheduled as follows: June 2 & 3; June 23 & 24; July 14 & 15; August 4 & 5; August 25 & 26. These events are free to all active Members, and everyone is invited to attend.  Please contact our office in advance to let us know you will be there: (530) 493-2012.

New Legal Fund Prize Drawing

Gold Eagle Coins

We will be giving away 15 prizes in our new legal-fund raiser:

Grand Prize: 1-ounce American Gold Eagle
Four ¼-ounce American Gold Eagles
Ten 1/10th-ounce American Gold Eagles

The drawing will take place at our weekly potluck in Happy Camp on Saturday, 7 July (2012).

The girls in our office automatically generate a ticket in your name for every $10 legal contribution that we receive ($100 would generate 10 tickets, etc).  There is no limit to the size or frequency of your contributions, or to the number of prizes you can win. Contributions can be called in to our office at (530) 493-2012, or they can be mailed to The New 49’ers, P.O. Box47, Happy Camp, CA 96039.  Or you can do it on our web site by going here:  Make a Donation

We greatly appreciate help from you in regenerating our legal fund!

2012 Group Insurance Policy

All Members are eligible to sign up for $10,000 of accidental medical Insurance which covers you while camping, prospecting for gold, and also during any activities which we sponsor. Dental accidents are included, along with $2,500 for accidental death or dismemberment.  The policy has a $100 deductable.  It is an annual policy which extends through January of 2013.  This insurance is available for $30 per year, per person. More information can be found here.

Sign up for the Free Internet Version of this Newsletter: We strongly encourage you to sign up for the free on line version of this newsletter.  The Internet version is better, because you can immediately click directly to many of the subjects which we discuss; because the on line version is in full color; because we link you directly to locations through GPS and Google Earth technology; and because you can watch the free video segments which we incorporate into our stories.

 

The New 49’ers Prospecting Association, 27 Davis Road, Happy Camp, California 96039 (530) 493-2012
www.goldgold.com

 
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This story first appeared in Gold & Treasure Hunter Magazine May/Jun, 1997 on Page 22.
This issue is still available! Click here.

By Dave McCracken

“It takes a huge amount of streambed in motion to cause large portions of the river to form new high-grade deposits.”

Dave Mack

It only takes a small amount of water force to move sand-sized particles downstream in a riverbed. It takes more water force to move pea-sized gravel downriver, and even more force to move baseball-sized rocks, and so on. It also takes a greater amount of water force to move larger particles of gold, than it does to move smaller ones – just like other streambed materials.

There is a massive amount of gold in gold-bearing waterways which is so small in particle-size that it floats in a state of suspension in the river-water itself. Some amount of gold is moving downstream in any gold-bearing river at any given time. An increase in water-flow increases the amount of streambed material and gold that is moved downstream.

Normal winter storms, for the most part, can move large amounts of fine and ultra-fine gold down the gold-bearing rivers. But this gold is likely to be so widely dispersed throughout the overall river that it is of little value to the modern river-prospector.

Today’s modern river-prospector is mostly interested in that gold which lies inside and underneath naturally-formed streambeds. For the most part, this gold will remain locked in place until a storm of major proportions comes along. Such a storm can cause so much water force in the river that large sections of pre-existing streambeds, and the gold that is within them, are swept up and washed downstream.

When a storm or snow-runoff of huge dimensions comes along and creates so much force of water flow that large portions of the riverbed are torn up and washed down along the bedrock, large portions of the bedrock will also get pounded loose, and any gold which was trapped in that bedrock will become washed further downstream along with the rest of the streambed material.

“Rough bedrock makes the best gold traps.”

The amount of gold still sitting inside streambeds of proven gold-bearing rivers is incalculable; there is a whole lot of it! Much was left behind in low-grade deposits which the early miners were not capable of mining at a profit. While there may been a lot of gold in some sections of river during the gold-rush years, it might also have been too widely dispersed or sitting underneath too much overburden to make the gold worth mining in those days. Other very rich deposits were missed because they were out of sight. Without processing every bit of streambed (which they did not have the capability to do), the old-timers simply could not find all of the gold deposits that existed during their time. A lot of gold that was excavated was never recovered. It was washed out of the high streambed deposits, through sluice boxes, and right back into the present rivers and creeks. This was particularly true of hydraulic mining, where an estimated 59% of the gold was missed by many of the large and small operations alike.

Also, the last 150 years of erosion has washed more gold into the present rivers and streams out of higher and older streambeds, and out of some lodes that are still in existence.

In taking all of this into consideration, we are talking about a lot of gold still existing in these gold-bearing rivers. In some cases, there is more gold present now than the amount that has already been mined out of them.

When a major storm occurs in a gold-bearing area and tears up large portions of streambed, a great deal of gold is set free and put into motion downriver. A fair amount of this newly-released gold, because of its superior weight, will be deposited in common areas along the riverbed. This is the type of gold that the modern gold prospector should be sampling for. The same major storm which causes enough force to tear up large portions of streambed material will also deposit most of that material into newly formed natural streambeds-even in those same areas which were once mined by the early miners.

During full flood stage, when streambed material and gold are moving free in the waterway, because it is so heavy, most of the gold will travel along a rather narrow path. This path is often referred to as the “gold line” by prospectors. Almost all high-grade pay-streaks will be located along this specific path. Therefore, the first step in prospecting is to locate where the common gold path is within the waterway. This very important principle is demonstrated by the following two video segments. Please take careful note of how the gold is attracted to the common line in the simulated river, regardless of where it is fed into the waterway:

For the most part, normal winter storms occurring in gold country do not create enough water force to do this. A winter storm might be enough to sweep up small portions of streambed in faster-moving sections of river and redeposit new streambeds in those areas, but this small amount of movement is not likely to put paying quantities of gold into play in the riverbed. It takes a huge amount of streambed in motion to place substantial amounts of gold into movement. This causes large portions of the river to form new placer deposits. Such storms occur occasionally, and are the main cause for a streambed cutting deeper into the earth as time goes along. Most gold-bearing areas have had at least one of these major storms since the early 1960’s. Alaska has major storms along with massive snow runoffs. So flood forces like this happen more often there.

When millions and millions of tons of rocks, cobbles, and boulders are being swept downstream along the bedrock foundation during a huge storm, the ground shakes and vibrates, and the river rumbles like a huge loaded freight train. After a major storm has been through an area, the plant growth, underbrush and weeds which normally grow along the river gravel bars, will be washed away. This will also be true with a lot of the growth, including trees, along the riverbanks.

It takes an incredible amount of water force to cause an entire riverbed to move downstream, but this is what it takes to form many new placer deposits in the river.

The following video was taken during the major flood storm that took place along the Klamath River in Northern California during early 1997. If you watch the footage closely, you will see places where the river is flowing down river with the full force of the storm, and you will see other places right alongside where the water is flowing in a reverse direction. This is important! Take note of the incredible amount of boiling which takes place between the different directions of flow. These are pay-streaks in the making; places within the waterway at flood stage where the river is not really flowing in either direction; but rather is boiling like a kettle of superheated water between opposing forces. Gold concentrates within these areas because there is not enough water velocity to keep it moving along. Each place along the common gold line within the waterway that a boil like this is created by the interplay of reverse-flows is where a prospector will find the high-grade pay-streaks. See how big the boiling areas are?

The earlier idea that gold drops into the river and simply is vibrated down through already formed streambeds to eventually reach bedrock and form a placer deposit is very limited in its workability. This theory does not lead a prospector into paying deposits of high-grade gold

Sometimes a storm will have enough force to move large amounts of gold, but will only move a portion of the entire streambed, leaving a lower stratum in place in some locations. When this happens, the gold moving along at the bottom of the flood-layer can become trapped by the irregularities of the unmoving (false bedrock) streambed layer lying underneath. The rocks along the surface of a lower stratum can act as natural gold traps.

Streambed layers caused by different flood storms are referred to as “flood layers.” Flood layers within a streambed are easily distinguished, because they are usually of a different color, consistency and hardness from the other layers of material within the streambed. Sometimes the bottom of a flood layer will contain more gold than is present on bedrock. Sometimes, when more than one flood layer is present in a streambed, there will be more than one layer of flood gold present, too. Gold deposits can often be found in the contact zone between the layers.

Flood layers that are caused by major flood storms are almost always found in a compacted state where the rocks and material hold together tightly and require tools to help pry them apart. In mining, we call this “hard-pack.” There is a big difference between hard-packed streambed and tailings from earlier mining activity or loose streambed material. Almost all high-grade pay-streaks will be found at the bottom of a layer of hard-pack. So it is very important that you know what it is. Please note how hard I have to work to break apart the hard-pack in one of the following 2 video segments:

The larger that a piece of gold is, the faster it will work its way down toward the bottom of a flood layer as it is being washed downstream during a flood. The finest-sized particles of gold might not work their way down through a flooding layer at all, but might remain dispersed up in the material.

So, you can run across a flood layer which has a line of the heavier pieces of gold along its bottom edge, or a flood layer which contains a large amount of fine gold dispersed throughout the entire layer. You can also run across a flood layer which contains a lot of fine gold dispersed throughout, in addition to a line of heavier gold along the bottom edge.

Not all flood layers contain gold in paying quantities for the small-sized mining operation. But in gold country, all flood layers do seem to contain gold in some quantity, even if only microscopic in size.

Some of the best areas to test for paying quantities of flood gold are where the stream or river widens out, or levels out, or changes the direction of its flow. Such places always cause the flow of water in a storm to slow up in certain locations. This can allow concentrations of gold to collect either on bedrock or in the contact zones between layers. These following important videos demonstrate the most common areas where pay-streaks are formed:

Gravel bars, especially the ones located towards the inside of bends, tend to collect gold. Flood gold in bar placers is sometimes consistently distributed throughout the entire gravel bar. Often the lower-end of a gravel bar is not as rich as the head of the bar, but the gold there can be more uniformly distributed throughout the material.

 

 

Article & photos by David Lawler, Consulting’ Geologist

 

Placer deposits image 1Placer gold deposits represent the most attractive targets for small-scale miners and prospectors, since activities can be carried out with reasonably small costs, and encouraging prospecting results can be obtained rapidly. A small-scale miner has the opportunity to exploit small, rich accumulations of gold which larger-sized mining companies might pass by, due to reserve-size and overall ore-grade. In other words, because of the higher costs involved with a larger mining company, they will not be interested in some types of gold deposits which can be quite lucrative for a smaller-scale mining program.

Placer deposits have been exploited by man since early historic times and have remained an important source of gold on the world market into the 20th Century.

Placer deposits have yielded over 60% of the world’s gold production. Placer gold production in California alone during the height of the Gold Rush has been estimated at $81 million dollars. (Dollar-value in terms of $18/ounce in 1849, prior to 150 years of inflation).

While many texts and articles have been written on the subject of placer mining, the purpose of this article is to provide a brief overview of the subject and to introduce relevant facts which have practical application for the small-scale miner. The less common types of placers, e.g., Glacial, Aeolian, Bajada and beach placers will not be covered in this article.

Alluvial Placer Gold Deposits

Placer deposits image 2Definition: Alluvial deposits are the most common type of placer gold deposit. This category includes fluxial (river and stream) placers which formed in well-defined channels. It also includes “bench” or terrace deposits. These are older river or streambeds which formed on the elevated side slopes of drainage valleys. Both ancient (paleo placers) and modern deposits are included in this category and have produced significant amounts of gold.

Characteristics: Good sorting of sediment and gold particles by size and weight.

Sediments tend to be well transported, reflecting significant rounding or flattening of individual particles as a function of distance traveled from its source. The source of gold can either originate from a nearby lode deposit, generally leaving the gold’s surface with a rough texture; or the gold can have originated from distant sources, generally leaving it with smooth, flattened particles, flakes or nuggets.

Ancient Fluvial Placer Deposits

Placer deposits image 3Examples: (Ancient) Tertiary-age Ancestral, Yuba and Feather River systems, Sierra Nevada Mountains, California, Ancestral Klamath River system, Weaverville and Hornbrook basins Klamath Mountains, California. There are also widespread occurrences of other ancient gold-bearing channels in other western states in the U.S.

Prospecting Suggestions: Check areas where modem drainages (rivers, creeks, and gullies) have eroded ancient gold-bearing channel deposits. Many of these areas were worked by miners during the 19th Century, but there is still plenty of gold remaining for the modem-day small-scale miner.

For example, check side slopes of ridges which contain the ancient channel deposits, since these are areas that usually could not be exploited by hydraulic or ground-sluicing mine methods, due to lack of adequate water or water pressure. These virgin (unexploited) areas can produce eroded substantial pockets of placer gold.

Hydraulic Mine Pit areas often contain good prospects for small-scale mining. Check the exposed bedrock floor (representing the exhumed channel base) surfaces both for cracks and weathered cemented gravels. Gold may remain in small fractures and cracks in the bedrock. These areas can be particularly fruitful for electronic prospecting.

In addition, gold may be liberated from previously-cemented gravels after the long period of weathering on the pit floor. Check drain tunnels and tailraces that may have been cut into bedrock or the sides of the channel for several reasons: First, drain tunnels were driven through solid bedrock at the floor of a hydraulic pit to drain excess water and tailings from the working face of a mining excavation.

It is estimated that hydraulic mining methods lost between 30% – 50% of the gold that was liberated from the deposit. In addition, many of the drain tunnels were also used as the primary locations for the placement of elongated sluice box recovery systems. Thus, clean-ups were performed inside the tunnels. Although some of the drain tunnels have become choked with debris or collapsed from weathering, many still carry gold-bearing materials through the tunnels.

Testing and sampling of in-situ (in place) Tertiary gravel placers is one very proven method of locating valuable gold deposits for the serious small-scale mining operation today.

Modem Fluvial Placer Deposits

Placer deposits image 4Examples: Rivers and streams of the Sierra Nevada and Klamath Mountain areas in California.

Prospecting Suggestions: Prospect areas which are adjacent to known ancient channels or lode gold deposits, since modern river deposits will usually become more enriched close to those areas.

Gold-bearing stream and river channels must be examined and studied in detail in regard to their history, habit and special characteristics, in order to better-exploit the placers contained in them. Check available geologic maps of a particular river area or observe the different bedrock types which are present. This information will yield valuable clues to the location and manner of gold accumulation in various stretches of river.

Most modern-day small-scale prospectors are using suction dredges, sluicing gear, vack-mining equipment and/or gold pans to prospect for and develop these types of gold deposits.

Sample bench deposits adjacent to the active stream margin. Although these deposits are not as commonly reworked by stream processes, they often contain high concentrations of placer gold. Thick bench deposits containing gold-bearing material derived from hydraulic mines are still present along the margins of rivers and streams in the Sierra Nevada and Klamath Mountain regions of California.

Residual Placer Deposits

Placer deposits image 5Definition: Shallow mineral deposits forming directly from weathering and chemical disintegration of a gold-bearing quality vein near the surface. Residual deposits tend to be rich, but localized in occurrence, i.e., close to the vein or outcrop area. These are also termed “seam diggings” due to their occurrence in weathered gold-bearing quartz stringers contained in weathered schist and slate fracture-zones.

Examples: “Seam digging”s at Georgia Slide, Spanish Dry Diggings and French Hill areas, Georgetown Divide, El’Dorado County, California, Alleghany and Downieville districts, Sierra County, California, Humboldt Mountains area, Humboldt County, Nevada.

Prospecting Suggestions: Search in lode gold districts characterized by small high-grade gold-quartz vein pocket deposits. Focus your search into specific areas which are along the geologic trend of previously-exploited lode pocket deposits. Recent fires, landslides, or disturbance by logging operations are constantly exposing new virgin areas for prospecting.

Modern-day metal detectors may help in the exploration and exploitation of these deposits, due to shallow overburden and erratic distribution of the residual placer nuggets.

Eluvial (hill-slope) Placer Deposits

Placer deposits image 6Definition: Deposits representing the transitional stages between a residual and alluvial placer deposit (deposits which form in route between the lode erosion and drainage system). Residual gold tends to form accumulations in soil or colluvium by “creeping” along with material down a hill-slope.

Examples: Klamath Mountain region, California and Oregon.

Prospecting Suggestions: A metal detector can be the ideal tool for locating these deposits, since gold distribution tends to be spotty or erratic due to a poor degree of sorting and transportation. High-banking equipment can be very productive where an adequate water source is available nearby. Dry-washing equipment can be productive in places where there is no water available for processing. Mechanized earth-moving equipment is sometimes necessary to excavate thick eluvial deposits. In this case, small wash plants are being used to recover the gold.

Recommended Reading

Averill C. v: 1946, Placer Mining for Gold in California: California Div. Mines Bull. 135, 377 p.

Clark, B. 1965, Tertiary Channels: California: Div. Mines and Geology Mineral Inf. Service, Z 18

Clark, B. 1970, Gold Districts of California: California Division of Mines Bull. 193, 186 p.

Haley, C.S., 1923, Gold Placers of California: California Mining Bur. Bull. 92, 167 p. Jenkins, O.P., 1946, Geology of Placer Deposits, in Averill, C. Z Placer Mining for Gold in California: California Div. Mines Bull. 135 p, p. 147-216.

Lindgren, 1911, The Tertiary Gravels of the Sierra Nevada of California: U.S. Geol. Survey Prof. Paper 73, 226 p.

Whitney, J.D., 1880, The Auriferous Gravels of the Sierra Nevada of California: Harvard Coll. Mus. Comp. Zoology Mem. v. 6, no 1, 569p.

 
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By Dave McCracken

Any place along the gold path where there is protection from the main flow of water is a good location to sample for gold.

Dave Mack

 

Thorndike/Barnhart’s Advanced Dictionary defines “placer” as “A deposit of sand, gravel or earth in the bed of a stream containing particles of gold or other valuable mineral.” The word “geology” in the same dictionary is defined as “The features of the earth’s crust in a place or region, rocks or rock formations of a particular area.” So in putting these two words together, we have “placer geology” as the nature and features of the formation of deposits of gold and other valuable minerals within a streambed

The main factor causing gold to become deposited in the locations where it does is its superior weight over the majority of other materials which end up in a streambed. By superior weight, I mean that a piece of gold will be heavier than most any other material which displaces an equal amount of space or volume. For example, a large boulder will weigh more than a half-ounce gold nugget; but if you chip off a piece of the boulder which displaces the exact same volume or mass as the gold nugget, the nugget will weigh about six times more than the chip of rock.

As gold is eroded from its original lode, gravity, wind, water and the other forces of nature may move it away and downwards until it eventually arrives in a streambed.

Gold erodes from its natural lode and eventually 
is washed into an active waterway.

There are several different types of gold deposits that a prospector should know about, because they have different characteristics and are dealt with in different ways. They are as follows:

RESIDUAL DEPOSIT: A “residual deposit” consists of those pieces of the lode which have broken away from the outcropping of the vein due to chemical and physical weathering, but have not yet been moved or washed away from the near vicinity of the lode. A residual deposit usually lies directly at the site of its lode.

ELUVIAL DEPOSIT: An “eluvial deposit” is composed of those pieces of ore and free gold which have eroded from a lode and have been moved away by the forces of nature, but have not yet been washed into a streambed. The fragments of an eluvial deposit are often spread out thinly down along the mountainside below the original lode. Usually, the various forces of nature cause an eluvial deposit to spread out more as its segments are washed further away from the lode deposit. Individual pieces of an eluvial deposit are popularly known as “float.”

An eluvial deposit contains those pieces of ore that have been swept
away from the lode which have not yet been deposited by running water.

BENCH DEPOSIT: (Also “terrace deposit”) Once gold reaches a streambed, it will be deposited in common ways by the effects of running water. Most of the remainder of this article will cover these ways. During an extended period of time, a stream of water will to cut deeper into the earth. This leaves portions of the older sections of streambed high and dry. Old streambeds which now rest above the present streams of water are referred to as “benches.” Accumulations of gold and other valuable minerals contained in an old, high streambed are called “bench deposits.”

An eluvial deposit might be swept down to rest on top of an old streambed (bench), but it will still remain as an eluvial deposit until it is washed into a stream of water. A bench placer deposit contains the gold deposited within that streambed before it was left high and dry.

Many benches are lying close to the present streams of water, and are actually the remains of the present stream as it ran a very long time ago.

Some dry streambeds (benches) are situated far away from any present stream of water. These are sometimes the remains of ancient rivers which ran before the present river systems were formed. Ancient stream benches are sometimes on top of mountains, far out into the deserts, or can be found near some of today’s streams and rivers. Ancient streambeds, wherever found, can contain rich deposits of gold.

Most surface placer gold mining operations today direct their activities at bench deposits. The reason for this is that the presence of an old streambed is evidence that it has never been mined before. Any gold once deposited there will still be in place.

STREAM PLACER: In order to discuss what happens to gold when it enters a stream of water, it is first necessary to understand the two terms: “bedrock” and “sediments.” Many millions of years ago, when the outer perimeter of the earth cooled, it hardened into a solid rock surface–called “bedrock” (or “country rock” when discussing the subject of lodes). All of the loose dirt, rocks, sand, gravel and boulders which lie on top of the earth’s outer hardrock surface (bedrock) are called “sediments.” In some areas, the sedimentary material lays hundreds of feet deep. In other areas, especially in mountainous country and at the seashore, the earth’s outer crust (bedrock) is completely exposed. Bedrock can usually be observed by driving down any highway and looking at where cuts have been made through the hard rock in order to make the highway straight and level.

Streambeds are composed of rocks, sand, gravel, clay and boulders (sediments) and always form on top of the bedrock foundation (although they can be later covered up by volcanic activity). Bedrock and country rock are the same thing.

Streambeds are composed of sediments which lie on top of bedrock.

The following video segment will allow you a visual demonstration of these very important points:

A large storm in mountainous country will cause the streams and rivers within the area to run deeper and faster than they normally do. This additional volume of water increases the amount of force and turbulence that flows over the top of the streambeds lying at the bottom of these waterways. Sometimes, in a very large storm, the increased force of water is enough to sweep the entire streambed down the surface of its underlying bedrock foundation. It is this action which causes a streambed to cut deeper into the earth over an extended period of time. A storm of this magnitude can also erode a significant amount of new gold into the streambeds where it will mix with the other materials.

Gold, being heavier than the other materials which are being swept downstream during a large storm, will work its way quickly to the bottom of these materials. The reason for this is that gold has a much higher specific gravity than the other streambed materials and so will exert a downward force against them. As the streambed is being vibrated and tossed around and pushed along by the tremendous torrent of water caused by the storm, gold will penetrate downward through the other materials until it reaches something which will stop its descent-like bedrock. This very important principle is demonstrated by the following video segment:

With the exception of the finer-sized pieces, it takes a lot of force to move gold. Since gold is about 6 times heavier than the average of other materials which commonly make up a streambed, it takes a lot more force to move gold down along the bedrock than it does to move the other streambed materials.

So there is the possibility of having enough force in a section of river because of a storm to sweep part of the streambed away, yet perhaps not enough force to move much of the gold lying on bedrock.

When there is enough force to move gold along the bottom of a riverbed, that gold can then become deposited in a new location wherever the force of the flow is lessened at the time of the storm.

Bedrock irregularities at the bottom of a streambed play a large role in determining where gold will become trapped. A crack or crevice along the bedrock surface is one good example of a bedrock gold trap.

Streambeds are composed of sediments which lie on top of bedrock.

Many bedrock gold traps are situated so that the main force of water, being enough to move gold, will sweep the traps clean of lighter streambed materials. This leaves a hole for the gold to drop into and become shielded from the main force of water and material which is moving across the bedrock. And there the gold will remain until some fluke of turbulence boils it out of the hole and back into the main force of water again, where it can then become trapped in some other such hole, and so on. The following video segment further demonstrates these important points:

Some types of bedrock are very rough and irregular, which allows for many, many gold traps along its surface.

Some bedrock surfaces are very rough and
irregular–which allows for many gold traps.

How well a crevice will trap gold depends greatly upon the shape of the crevice itself and its direction in relation to the flow of water during a flood storm. Crevices extending out horizontally into a riverbed can be very effective gold-catchers, because the force of water can be enough to keep the upper part of the crevice clean of material, yet the shape and depth of the crevice may prevent gold from being swept or boiled out once it is inside.

Crevices running lengthwise with the flow of the stream or in a diagonal direction across the bed can be good gold traps or poor ones, depending upon the shape of the crevice and the set of circumstances covering each separate situation. For the most part, water force can get into a lengthwise crevice and prevent a great deal of gold from being trapped inside. However, this mostly depends upon the characteristics of the bedrock surface, and there are so many possible variables that it is no use trying to cover them all-such as the possibility of a large rock becoming lodged inside a lengthwise crevice, making its entire length a gold trap of bonanza dimensions. There is really no need to say much more about lengthwise-type crevices. Because if you are mining along and uncover one, you are going to clean it out to see what lies inside, anyway.

Potholes in the bedrock foundation of a streambed have a tendency to trap gold very well. These usually occur where the bedrock surface is deteriorating and some portions are coming apart faster than others, leaving holes which gold can drop into and thereafter be protected from the main force of water.

Bedrock dikes (upcroppings of a harder type of bedrock) protruding up through the floor of a streambed can make excellent gold traps in different ways, depending upon the direction of the dike. For example, if a dike protrudes up through the floor of a streambed and is slanted in a downstream direction, gold will usually become trapped behind the dike where it becomes shielded from the main force of the flow. A dike slanting in an upstream direction is more likely to trap gold in a little pocket just up in front.

Hairline cracks in the bedrock surface of a streambed often contain surprising amounts of gold. Sometimes you can take out pieces of gold that seem to be too large for the cracks that you find them inside of, and it leaves you wondering how they got there. Once in a while, a hairline crack will open up into a space which holds a nice little pocket of gold.

Hairline cracks can hold plenty of gold, and sometimes open up into small pockets.

How smooth the bedrock surface is has a great deal to do with how well its various irregularities will catch gold. Some types of bedrock, like granite for example, are extremely hard and tend to become pounded into a smooth and polished surface. Polished bedrock surfaces like this generally do not trap particles of gold nearly as well as the rough types of bedrock surfaces do. Also, polished bedrock, which sometimes contains large, deep “boil holes” (holes which have been bored into the bedrock by enormous amounts of water turbulence), is often an indication of too much turbulent water force to allow very much gold to settle there during flood storms.

Rougher types of bedrock, often being full of both large and small irregularities, have the kind of surface where many paying placer deposits are found. This kind of bedrock can be very hard and still maintain its roughness. Or it can be semi-decomposed. Either way, it can trap gold very well.

Rough bedrock surfaces tend to trap gold very well.

Basically, anywhere rough bedrock is situated so that its irregularities can slacken the force of water, in a location where gold will travel, is a likely place to find gold trapped.

Obstructions in a streambed can also cause the flow of water to slow down and can be the cause of a gold deposit, sometimes in front and sometimes to the rear of the obstruction. An outcropping of bedrock jutting out into a stream or river from one side can trap gold in various ways, depending upon the shape of the outcropping and the direction it protrudes into the stream. An outcropping extending out into the river in an upstream direction is most likely to trap gold in front of the outcropping where there is a lull in the water force. A gold deposit is more likely to be found on the downstream side of an outcropping which juts out into the river in a downstream direction, because that is where the force of the flow lets up.

LARGER GOLD TRAPS: PAY-STREAK AREAS

One of the most common locations within a stream or river to find a gold deposit is where the bedrock drops off suddenly to form a deep-water pool. Any place where a fixed volume of water suddenly flows into a much larger volume of water is a place where the flow may slow down. Wherever the flow of water in a streambed slows down during a major flood storm is a good place for gold to be dropped. And so it is not uncommon to find a sizable gold deposit in a streambed where there is a sudden drop-off into deeper water.

Any sudden drop-off into a deeper and larger volume of water is a likely spot to look for a sizable deposit of gold.

A waterfall is the extreme example of a sudden bedrock drop-off and can sometimes have a large deposit of gold at its base-but not always. Sometimes the water will plunge down into the hole of the falls and create so much turbulence that gold dropped into the hole during a storm can become ground up or boiled out. This is also potentially true of any other lesser sudden drop-off locations inside of a waterway.

On the other hand, sometimes large boulders can become trapped at the base of a falls and protect the gold from becoming ground up or boiled out by the turbulence. In this case the falls can become a bonanza.

In some waterfalls (or lesser sudden drop-off locations) the gold that has been boiled out will drop just outside of the hole, where the force of water has not yet had enough runway to pick up speed again-at least not enough to carry off much of the gold which arrives there.

Waterfalls are usually the territory of the suction dredger, because this type of gold trap usually deposits the gold underwater. Yet, this is not always the case. Sometimes during the low water periods of the year, some of the area below a falls can be exposed. There might be only a small amount of streambed to move in order to reach bedrock-where most of the gold is likely to be. The only dependable way to determine if gold will be present below a falls, or any other sudden drop-off location in a waterway, is to sample around and find out. Usually this is rather easy (unless you run into huge boulders); because if the area has been boiled out and swept clean of gold, often the bedrock will be exposed or have a layer of light sand and gravel on top. Again, this is not always true. Each falls has its own individual set of circumstances.

Another common location where a sizable gold deposit might be found is where the layout of the countryside causes the stream to run downhill at a rather steep grade for some distance and then suddenly it levels off. It is just below where the slope of the streambed levels off that the water flow will suddenly slow down during a major flood storm. This is where you are likely to find a concentration of gold. Areas like this are known for their very large deposits (pay-streaks).

The area just below where a streambed’s slope lessens often contains a good-sized gold deposit.

Boulders are another type of obstruction which can be in a riverbed and cause gold to drop out of a fast flow of water. Boulders are similar to gold in that the larger they are, the more water force it takes to move them. Sometimes during a storm, the force of water can pick up enough to sweep large amounts of streambed material and gold down across the bedrock. When this happens, the force may or may not be great enough to move the large boulders. A large boulder which is at rest in a stream, while a torrent of water and material is being swept past it during a large storm, will slow down the flow of the stream just in front, below and somewhere behind the boulder. This being the case, if the storm’s torrent happens to sweep gold near the boulder, some of the gold may concentrate where the slackening of current is at the time of the storm.

A boulder at rest in a streambed during a large storm might trap gold wherever it slows down the water force.

One thing to know about boulders is that they do not always have gold trapped around them. Whether or not a specific boulder will have a deposit of gold along with it depends greatly upon whether or not that boulder is in the direct path the gold took when it traveled through that particular section of streambed during earlier major flood storm periods.

THE PATH THAT GOLD FOLLOWS

Because of its weight, gold tends to travel down along a streambed taking the path of least resistance. For the most part, this seems to be the shortest route possible between major bends in the stream.

Gold tends to follow the shortest route possible between any major changes in the direction of the stream or river.

Take note that the route the gold is taking rounds each curve towards the inside of the bends in the river. While this might not be the route gold always takes in a streambed, it is true that when it comes to curves, the majority of gold deposits are found towards the inside of bends. In comparison, very few are found towards the outside. Centrifugal force causes a much greater energy of flow to the outside of the bend. This creates less force towards the inside, which allows for gold to drop there.

 

It is important for you as a prospector to grasp the concept that under most conditions, gold tends to travel the shortest distance between the bends of a stream or river, and it also seems to deposit along the inside of the bends. Your best bet in prospecting is to direct your sampling activities towards areas which lie in the path that gold would most likely follow in its route downstream within the waterway. This requires an understanding of what effects the various changes in bedrock and the numerous obstructions will have on changing and directing the path of gold as it is pushed downstream during extreme high water periods. For example, if you are sampling for concentrations of gold around and behind boulders, you are better off to begin with the boulders lying in the path that gold would most likely take. This is likely to be more productive than just sampling boulders randomly in the streambed, no matter where they are located.

WHERE THE STREAMBED WIDENS

Another situation within a stream or river where there is often a sizable concentration of gold (pay-streak) is where the stream runs narrow or at a certain general width for some distance and then suddenly opens up into a wider portion of streambed. Where the streambed widens, the water flow will generally slow down, because the streambed allows for a larger volume of water in such a location-especially during extreme high water periods. Where water force slows down is a likely place for gold to drop.

Anywhere that a streambed suddenly widens enough to slow the force of the
stream during high water periods is a likely place to find a deposit of gold.

Notice that some boulders will also drop where the water force is suddenly slowed down. Boulders are similar to gold in that it takes a tremendous amount of force to push them along. Wherever that force lets up enough, the boulders will drop. So boulders are often found in the same areas where large amounts of gold are deposited. But gold is not always found where boulders are dropped. This is because there are so many boulders within the waterway, and the majority of them probably do not continuously follow the same route that gold generally takes. Nevertheless, it is well to take note that those places where boulders do get hung up, which are on the same route that gold follows down the waterway, are generally good places to direct some of your sampling activities.

ANCIENT RIVERS

About two million years ago, towards the end of the Tertiary geological time period, the mountain systems in the western United States underwent a tremendous amount of faulting and twisting, changing the character of the mountains into much of how they look today. It was during the same period when the present drainage system of streams, creeks and rivers were formed, which runs pretty-much in a westerly direction.

Prior to that, there was a vastly different river system, which generally ran in a southerly direction. These were the old streambeds which ran throughout much of the Tertiary geologic time period, and so are called “tertiary channels” or“ancient rivers.” The ancient rivers ran for millions of years, during which time an enormous amount of erosion took place, washing very substantial amounts of gold into the rivers from the exposed rich lode deposits.

The major changes occurring towards the end of that period, which rearranged the mountains and formed the present drainage systems, left portions of the ancient channels strewn about. Some portions were placed on top of the present mountains. Some were left out in the desert areas. And some portions were left close to, and crossed by, the present drainage system.

Some geologists have argued that most of the gold in today’s river systems is not gold that has eroded more recently from lode deposits, but gold that was eroded out of the old ancient riverbeds where they have been crossed by the present river systems.

The ancient channels, where they have been discovered and mined, have often proven to be extremely rich in gold deposits. In fact, many of the richest bonanzas that have been found in today’s river systems have been discovered directly downstream from where they have crossed the ancient streambed gravels. Other areas which have proven to be very rich in today’s river systems have been found close to the old channels, where a few million years of erosion have caused some of the channel and its gold to be eroded into the present streambeds.

Ancient channels (benches) are well known for their very rich bottom stratum. This stratum is sometimes of a deep blue color; and indeed the rich blue color, when encountered, is one of the most certain indicators that ancient gravels are present. This bottom stratum of the ancient gravels was referred to by the old-timers as the “blue lead”, probably because they followed its path all over the west wherever it led them.

Ancient blue gravels usually oxidize and turn a rusty reddish brown color after being dug up and exposed to the atmosphere. They can be very hard and compacted, but are not always that way.

Running into blue gravel at the bottom of a streambed does not necessarily mean that you have located an ancient channel. But it is possible that you have located some ancient gravel (deposited there from somewhere else) which might have a rich pay-streak associated with them.

Most of the high benches that you will find up alongside today’s rivers and streams, and sometimes a fair distance away, but which travel generally in the same direction, are not Tertiary channels. They are more likely the earlier remnants of the present rivers and streams. These old streambeds are referred to by geologists as “Pleistocene channels.” They were formed and ran during the time period between 10,000 years ago and about a million and a half years ago — which was the earlier part of the Quaternary Period, known as the Pleistocene epoch. Some high benches that rest alongside the present streams and rivers were formed since the passing of the Pleistocene epoch. These are referred to as “Recent benches,” having been formed during the “Recent epoch” (present epoch).

Some of these benches, either Pleistocene or Recent, are quite extensive in size. Dry streambeds are scattered about all over gold country, some which have already been mined, but many are still untouched.

Usually, all that is left of a bench after it has been mined are rock piles. Notice in the picture that part of the non-mined streambed is in the background, behind the trees.

Usually all that is left of a high bench after it has been mined are piles of the larger-sized streambed rocks and boulders.

Most of the hydraulic mining operations which operated during the early to mid-1900’s were directed at high benches.“Hydraulic mining” was done by directing a large volume of water, under great pressure, at a streambed to erode its gravels out of the bed and through recovery systems, where the gold would be trapped.

A hydraulic mining operation. Photo courtesy of Siskiyou County Historical Museum.

So some bench gravels have been mined, but many of them still remain intact. While the Pleistocene and Recent benches are generally not as rich in gold content as were the Tertiary’s, it still remains true that an enormous amount of gold washed down into these old channels when they were active. They are pretty darn rich in some areas, and pay rather consistently in others. Also, any and all gold that has ever washed down into an old bench which has yet to be mined still remains there today.

FLOOD GOLD

A large percentage of the gold found in today’s creeks and rivers has been washed down into them out of the higher bench deposits by the erosive effects of storms and time. A certain amount of gold is being washed downstream in any river located in gold country at all times, even if only microscopic in size.

The larger a piece of gold is, the more water force that it takes to move it downstream in a riverbed. The amount of water force it takes to move a significant amount of gold in a riverbed is usually enough force to also move the streambed, too. This would allow the gold to work its way quickly down to the bedrock, where it can become trapped in the various irregularities.

Some streambeds contain a high mineral content and grow very hard after being in place for an extended period of time.

Sometimes a storm will have enough force to move large amounts of gold, but will only move a portion of the entire streambed, leaving a lower stratum in place in some locations. When this happens, the gold moving along at the bottom of the flooding layer can become trapped by the irregularities of the unmoving (“false bedrock”) streambed layer lying underneath. The rocks in a stable lower stratum can act as natural gold traps.

Flood gold is that gold which rests inside and at the bottom of a flooding layer.

Different streambed layers, caused by major flood storms, are referred to as “flood layers.” The flood layers within a streambed, if present, are easily distinguished because they are usually of a different color, consistency and hardness from the other layers of material within the streambed. That gold found at the bottom of or throughout a flood layer is often referred to as “flood gold.” Sometimes, the bottom of a flood layer will contain substantially more gold than is present on bedrock. Sometimes, when more than one flood layer is present in a streambed, there will be more than one layer of flood gold present, too.

The larger that a piece of gold is, the faster it will work its way down towards the bottom of a layer of material as it is being washed downstream during a storm. Finer-sized pieces of gold might not work their way down through a flood layer at all, but might remain disbursed up in the material.

So you can run across a flood layer which has a line of the heavier pieces of gold along its bottom edge, or a flood layer which contains a large amount of fine gold dispersed throughout the entire layer. You can also run across a flood layer which contains a lot of fine gold dispersed throughout, in addition to a line of heavier gold along the bottom edge.

Not all flood layers contain gold in paying quantities for a small-scale mining program. But in gold country, all flood layers do seem to contain gold in some quantity, even if only microscopic in size.

GRAVEL BAR PLACERS

Gravel bars located in streambeds flowing through gold country, especially the ones located towards the inside of bends, tend to collect a lot of flood gold, and sometimes in paying quantities even for the smaller-sized operations. The flood gold in bar placers is sometimes consistently distributed throughout the entire gravel bar. Sometimes the lower-end of a gravel bar is not as rich as the head of the bar, but the gold there can be more uniformly dispersed throughout the material.

FALSE BEDROCK

Once in a while a prospector will uncover an extremely hard layer of streambed material located just above the bedrock and mistake the layer for bedrock because of its hardness. A hard layer is often referred to as “false bedrock.” Such a layer can consist of streambed material, or of volcanic flows which have laid down and hardened on top of bedrock, or it can consist of any kind of mineral deposit which has hardened over time on top of the true bedrock.

There can be a good-paying gold deposit underneath a false bedrock layer. But when there is, it is usually rather difficult to get at.

Actually, for the purpose of sampling, the top of every different storm layer within a streambed should be considered a“false bedrock” and can be a surface-area for gold to become trapped out of the flood layer which laid down on top.

 
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By Dave McCracken

“Good organization always comes back to having some understanding in advance of what conditions you will encounter when it is time to complete the mission.”

 

Assuming legal access to the property has already been arranged, and company executives intend for us to proceed in this way, here are the primary objectives that we try and accomplish during the preliminary evaluation of a potential mining project:

1) Meet with company executives to gain an understanding of what the mining program is about, what the overall objectives are, the timing and the budget. Review the information which they have accumulated so far. Make plans for a departure-date.

2) Obtain the very best maps of the area that we can get our hands on.

3) Locate and study as much information as we can find concerning the mining history of the area, and the areas surrounding where the project will take place. Plot this information on the map. This includes finding out the type of mining methods that were being used, and what kinds of values have been recovered.

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4) Study background information about the geology, weather, culture, politics and economics of the area. This includes a look at the public information released by the U.S. State Department . Follow up with Internet research to see what others have to say about the people, events and mining activity within the area – and anything else of interest.

Is the political situation stable?

5) Establish a preliminary idea of how and where the potential project-area is located in relation to local communities, potential sources of supplies, emergency support, political structure and access. Bring together an early idea of what we want to see when we get there.

6) I always recommend that at least one representative (preferably one of the company directors) of the company accompany us through the full preliminary evaluation of the area where the potential project would take place. It is in the company’s best interest to have someone from existing management present to confirm our observations, and to help evaluate our conclusions.

7) Travel to the potential project area and:

A) Get a feel for the local politics in general, and in relation to the potential project. Will the locals ignore, support or object to the program? Are there pre-existing problems that will need to be fixed before beginning a sampling program? For example, the following video segment shows local campaigning on political issues within Madagascar that soon thereafter evolved into civil strife that disrupted all productive activity in the country for at least 6 months:

B) Find out the different ways of gaining access to the project site. Try and make contact with those people who would provide the transport service (if needed), and establish timing, cost and dependability. How can we make contact with them from the field? For example, the following video segments demonstrate boat transport services we needed to rely upon to support a dredging project in Cambodia :

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C) Locate sources of food, fuel, supplies and personnel to support the mining program. This would include any special needs, like local guides and boat operators out at the project-site. Establish the cost of things and dependability of the supply and/or services. Are there periodic shortages of supplies or services?

    

 

D) Locate the nearest place for competent medical assistance. Do they have any kind of emergency evacuation service? If not, perhaps they can provide a referral to the nearest large medical facility which does provide such a service. Develop a viable plan to provide competent medical care in the event that it may be needed, and how to mobilize the service from the field.

E) Establish support in local communities within the vicinity of where we would conduct the mining operations.

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F) Locate local miners and gain as much information as possible from them about what is being done, where and what results are being accomplished. Purchase samples of the values if possible and carefully log where they came from. Take a hard look at the gold, gemstones or other values being recovered. It is important to verify the activity and results. Look at how much value the locals are recovering, in relation to the volume of their production. Relate that back to what can be accomplished in production with suction dredging or other modern equipment.

    

 

    

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For example, the following video segment demonstrates a primitive hand-mining program that I stumbled upon along the border of western Viet Nam just a short while ago. These miners were breaking very small volumes of hard-rock ore free from the surrounding country rock with a hammer and chisel. The pieces of ore were being crushed by hand, and then surprising amounts of free gold were being panned in the river where we were sampling. While the amount of gold actually being recovered was not a lot, it was very rich compared to the very small amount of ore that was being processed by their primitive methods. Modern equipment and technology would turn this into an extremely valuable deposit:

The best local mining operations to observe are the ones that are actively processing the gravels within the waterway where our dredging would be done in a follow-up sampling operation.

For example, I captured the following video sequence where active gold mining was being done by local miners alongside and inside of the river where we were considering a suction dredge program in Africa several years ago. As the local miners were recovering a lot of gold in proportion to the volume of river gravels being processed, we decided that a follow-up dredge sampling program was justified:

G) Find out if there are special concerns about dangers in the water, within the surrounding area, sanitary problems, health concerns, or security worries. How will they be dealt with? Will there be any special needs for this?

For example, the following two video sequences were captured during a dredge sampling project that we completed in Cambodia several years ago at a time when there was an active (brutal) civil war in progress. The dangerous situation at the time required us to bring along a substantial contingent of security forces and also arm each of the specialists on our team:

Is the waterway full of big rocks that will require specialized equipment to winch out of our way?

    

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H) Free-dive in the river and/or probe from the surface to gain a good perception of what equipment will be needed to perform a preliminary sampling program. How deep and fast is the water? How deep is the streambed material to bedrock? Is there a lot of material too large to move by hand? Are submerged trees going to interfere with the sampling process? Are there excessive amounts of mud or sand that will overwhelm the recovery system?

It is often possible to bring up smaller-sized samples to pan from the bottom of the river, to get a better idea what a dredge sampling program will find.

I) Decide if special recovery methods will be required to perform a preliminary sampling program. If conditions present will mean that more portable equipment will be required, this may require a floating container be constructed to fully catch the samples, so they can be carefully processed on shore.

Or it may be that you can refit your sampling dredge so that it will effectively capture the fine gold from your samples. Here is a substantial explanation of the system which we have developed to effectively recover more fine gold on our conventional suction dredges. It combines two classification screens to more-effectively separate material-feed into three size-fractions, each which is directed into a different recovery system. The smallest gold particles (which are most difficult to recover) are directed into low-profile riffles along the bottom of the sluice box which have long been proven to be very effective at trapping fine gold.

  

J) Establish the potential for a commercial mining opportunity, based upon evaluation of pre-existing information and direct observation of ongoing local mining programs, along with whatever limited sampling can be accomplished using the resources that are immediately available.

K) Document all important details as well as possible by logging names, phone numbers (or email addresses) and locations of important contact persons, along with how much things will cost. Obtain digital images of everything important..

L) If appropriate, conceptualize a preliminary sampling program. This includes how the sampling program would be performed, supported, and how long it would take to complete. The concept should be consistent with the company objectives and budget.

8) Write a report which includes all of the important details of our findings. Include a photo-library with explanations for each image. The report should conclude with a recommendation. For example, Here is an example of the non-proprietary portion of a completed Report.

For a better understanding of why a preliminary evaluation is so important, I strongly encourage you to read about some of the sampling projects that we have accomplished in remote locations outside of America. The full list of the adventures I have written about can be found here . When reading these stories, it should become very clear to you that the potential success of any sampling program will largely come back to how well it is organized in advance. Good organization always comes back to having some understanding in advance of what conditions you will encounter when it is time to complete the mission.

 

 

By Dave McCracken

There is always action and controversy of some kind going on in the gold mining business. I guess that’s why most of us like it so much!

One thing about participating in gold mining or prospecting, is that it is never boring. Nor is any part of the administration of the gold mining industry boring. There is always some action going on!

This is one of the things which makes our industry so interesting. People who participate tend to be non-conformists by nature, or at least on a temporary non-conformist quest of some kind.

Some people get involved in gold prospecting as an escape from the humdrum of their normal, everyday existence; get up early, go to work, come home, watch TV and go to bed, try and pay the bills on time, etc.

Getting out into the great outdoors on a quest for adventure, even on the most remote possibility that something of value may be found, is enough of a lure for many to pursue prospecting activities. In some cases, it is not the gold which is of primary importance. When found, the gold is just a bonus to many participants. The real treasure is the opportunity to get physically and emotionally free of our normal, everyday existence. This is refreshing and revitalizing. It gives us a chance to put things back in a more balanced perspective.

It’s been said that the best way to solve a problem is to get outside of the problem and view it from the outside. Sometimes it’s not enough to take a walk or go for a drive. Sometimes, the best way to get out of a problem, or to be able to view a whole existence from the outside, is to launch yourself into a new adventure or a new existence. After a few days on a quest, or in a complete new environment, or after a few days in a brand new dramatic activity, you can often look back at earlier problems, or your normal life, and see them far more clearly. Everyone can gain from an exciting vacation or experience.

Different people gain different things from being involved with our activity. While one person might get back in touch with the basics of nature, another might connect with the historical values of those who were there many years ago. Others enjoy the search and the excitement of the potential find. Some are emotionally disappointed in not finding what they are looking for. But everyone is touched in some way. These activities are never dull.

Even the guy that wasn’t able to find any gold this time, while perhaps disappointed at this moment, at the same time he is not all caught up in the problems at the office. He stopped thinking about the office last week. Right now, he is planning his next adventure in such a way as to improve the amount of gold he will find.

There can be more to life than normal survival routines, raising the family, earning the pension and paying off the house. This is where dreams come in. Take a person’s dreams away and you have destroyed that person. It is not only about how much gold the person finds. It is the fact that the person desires and is interested in going out looking. This is therapy; a person pursuing his or her dreams, no matter how silly or inconsequential those dreams may be to others with dissimilar interests.

Being involved with the administration of the industry is not dull, either! People associated with this business are either friendly and supportive, or they are out to do us in. The controversy over the 1872 Mining Law is just one example; those people who are against us will invent just about any lie or excuse why all mining should be stopped. There is no middle ground. There is no reason. But there is drama; plenty of it!

And this is the way our whole industry is. Some people are excited. Some people are disappointed. Some people like us. Some people hate us. Some people want to tell you the whole story about the rich gold deposit they are looking for. Some people are incredibly secretive. Some people want to share the gold deposit they located with all the other miners and friends in the area. Others want to keep all the gold for themselves. Some people want to argue and complain about what the problems are that face our industry. Others are willing to pitch in and give a hand to help resolve problems. But there is always action and controversy of some kind going on. Gold mining is never boring. I guess that’s why most of us like it so much!

 

BY STEVE HICKS

Placer miners at work

Placer mining is relatively simple as long as you don’t expect to make a profit; but it becomes much more difficult if your intention is to make some money. If you want to make some money, it’s a lot easier and cheaper to learn from other people’s mistakes, than to put yourself through the school of hard knocks. By far, the most common mistake I see is inadequate or improper sampling, which is often due to gold fever. Other mistakes are: not properly cleaning up bedrock, not researching the past mining history of your area, and starting a mining venture under-funded.

Placer miners diggingFirst, we will cover sampling. A common remark I hear is why put the time, effort, money, etc. into sampling when it can be better-spent on actual mining and making some money? All too often, individuals lose thousands of dollars on their mining ventures; but had they done some sampling and found out that the ground was too low-grade to mine profitably, they would have only spent hundreds of dollars. I have seen an individual go broke trying to mine ground containing less than $2 of gold per yard when there was un-mined ground about 300 yards away running slightly over $100 per yard. That is not a typographical error; it is one hundred dollars. This is, of course, an extreme example; but all too often rich ground is missed. Even before sampling, a literature-search is in order to get an idea of the ground’s value.

Another common mistake is not separating overburden from pay gravels. Novice miners frequently like to run low-grade overburden. This is because the more gravel they mine, the more gold they recover. While mining everything on a property will maximize the amount of recovered gold, it could bankrupt a person at the same time. If the overburden only contains $2 of gold per yard, and your mining cost is $5 per yard, then you are losing $3 for every yard put through the wash plant.

On the other hand, if you can strip low-grade overburden for $1 per yard, then you have saved $2 per yard which can be directed toward mining the pay gravels.

Gold sample in panOften, new miners leave a lot of gold values in the bedrock. Some highly-fractured bedrock may have values several feet below the surface. The deepest I have ever read about was a Canadian mine going down nine feet into bedrock to get all of the values.

Most often, the bedrock values will be in the top two feet of bedrock. Once you mine the top six inches, check the next six inches to see if there are still enough values to make it pay. Once again, you must evaluate your mining costs for ripping up bedrock to determine if the effort will pay adequate dividends.

Starting a placer operation under-funded is another common mistake of novice miners. It is a mistake to count on finding some profitable ground to pay off debts right away and carry you through the rest of the season. Unforeseen problems have a way of cropping up, such as equipment breakdowns or a severe water shortage later in the season.

Even though most individuals reading this article won’t be running a large-scale mining operation, these tips should help you toward a more profitable operation even on a smaller-scale. Maybe, with some increased sampling or more efficient mining, you just may find that big nugget this season!

About the Author: Steve Hicks is a geologist specializing in sampling gold placers. He has previously worked a number of years as a mineral examiner for the BLM in Alaska and Montana. Presently he is doing placer consulting work and residing in Livingston, Montana.

 
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This story first appeared in Gold & Treasure Hunter Magazine Nov/Dec, 1991 on Page 29. This issue is still available! Click here.

By Dave McCracken

It is nearly always important for a prospector to target his or her sampling efforts to reach the bottom of hard-packed streambeds.

Dave Mack

 

Successful mining in streambeds is generally accomplished in two steps: (1) prospecting and (2) production. This is true on any scale of operation. First, you need to find a gold deposit, usually a pay-streak. Once the deposit is located, then you can concentrate on a production program to recover the gold from the deposit.

Prospecting generally consists of digging or dredging sample-holes in different locations, then comparing the results of the different samples. Through trial and error, the positive signs are then followed into high-grade gold deposits.

In a waterway, the first effort should be to locate the common path along which most of the gold typically travels. Sampling is then performed along that path to find the pay-streaks. This system is thoroughly outlined in Gold Mining in the 21st Century, and Part 1 of Advanced Dredging Techniques.

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The following video clip also demonstrates this very important principle:

When you are sampling, you should nearly always be looking for hard-packed streambed material. “Hard-pack” is created at the bottom of waterways during major flood-storms.

Generally, a winter storm, even a large winter storm, will not create enough turbulence and force within a river, creek or stream to redeposit the compacted streambeds that are already in place along the bottom.

Flood-storms of the magnitude to redeposit streambeds do not occur very often.

For example, on the Klamath River in northern California, where my own team dredging operations take place during the summer months, we believe the last time that a substantial amount of hard-packed streambed was formed was during the 1997 flood. An even larger storm took place in 1964. In many places, a 1964 flood-layer was laid down on top of a much older, harder-packed, virgin streambed — one formed perhaps thousands of years ago.

To give you an idea of the magnitude of storm that it takes to create hard-packed stream-beds, take a look at the following video sequence I captured just down river from Happy Camp during the flood of 1997:

So, it takes a major flood storm to move and lay down a hard-packed streambed. And, it takes a super-sized major flood storm to create enough force and turbulence in a river to break up ancient streambeds and redeposit them as newer hard-packed streambeds along the course of the waterway. This happens only very rarely.

The reason that hard-pack is important to a prospector is because gold nearly always concentrates at the bottom of hard-packed, flood layers. Therefore, it is nearly always important for a prospector to target his or her sampling efforts to reach the bottom of hard-packed streambeds.

The following video sequence shows exactly what hard-pack looks like. I captured this video during a Group Mining Project in a location where we were recovering a rich gold deposit from the bottom of an ancient streambed layer resting on bedrock:

Gold is about six times heavier, by volume, than the average weight of the sand, silt, and rocks that make up an average streambed. Because of this disparity in weight, when streambed material is being washed downriver during a major flood-storm, most of the gold will quickly work its way down to the bottom of the streambed material that is being carried along by the raging flood waters.

In the following video segment, watch how fast the gold penetrates average streambed material once it is placed into suspension. The second video segment provides a visual demonstration of this very important point:

Because the gold is so much heavier, it will work its way down along the river-channel more slowly than the other streambed materials. During major flood-storms, most of the gold moving in a waterway will be washed down across the bedrock, or across the surface of hard-packed streambed that is not being moved by the storm. At some point during the storm, gold becomes trapped out of the turbulent flow by dropping into irregularities, cracks and holes that are present along the surface over which it is traveling.

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As shown in the following video segment, other heavy materials, like lead and old iron objects, also travel and deposit in the same places as gold. These other materials can sometimes lead you right into a rich gold deposit:

Because of its enormous weight, gold also deposits much earlier during the course of the storm than the streambed material which eventually seats itself on top of a pay-streak. As the storm begins to taper off, and the water-forces begin to slow down, particles of gold will start dropping out of the flow. Along the path where most of the gold is traveling in the waterway, traces will be deposited, with more substantial pay-streaks forming within the larger, low-velocity areas. These gold deposits are being laid down even as the (much-lighter) rocks and gravel are still being washed down river with the storm flows. Streambeds form later in the storm, when the water-turbulence tapers off enough to allow the rocks, gravel, sand and silt to drop out of the flow and form a seated bed along the bottom (over top of the gold).

Streambed material that lies in on top of a pay-streak will nearly always be hard-packed. The reason for this is that if there is enough force and turbulence to move substantial amounts of gold in the waterway, then there is also enough force to create a naturally-formed streambed on top of the gold as the same storm tapers off.

How do natural streambeds form? First, the storm needs to be powerful enough to rip up the streambed material, put it into suspension, and wash it down the waterway. This process is similar to gravel washing through a sluice box, only on a much larger scale. During the later course of the storm, as the water-force and turbulence starts slowing down, natural obstructions or traps along the river-bottom will allow certain key rocks to become lodged or seated. An example might be a flat rock that drops into a bedrock indentation, with the forward edge of the rock pointing slightly downward into the flow. The water-current then holds the rock to the bottom. With this rock in place, new locations are formed for other rocks to become lodged. Smaller rocks, sand, gravel, and silt will fill every gap and crevice in a manner similar to the mortar used to cement layers of brick. More rocks then fall into place. More filler then packs the spaces created between the rocks, and the bed forms.

Hard-packed streambeds form mostly with the flat rocks lying horizontally and slightly tipped downward against the direction of the current. The way in which streambeds form during major flood storms leaves the bed-material seated and compacted together, much like a mechanical structure. In dredging, we call this structure “hard-pack.” Most of the gold in present waterways is covered over by hard-packed streambed. So it is very important to know what it is. The following video segment shows you exactly what to look for:

For substantial amounts of gold to move within a waterway, it requires a major flood-storm with enough power to blast up some of the pre-existing hard-packed streambeds. This is because most of the existing gold in the waterway is trapped below existing hard-packed streambeds.

It is the abrasive action of the streambed material (more like a huge band-saw), as it is being washed down along the bedrock during major flood-storms, that causes bedrock channels to cut deeper into the earth over geologic time. When such a storm tapers off, new hard-packed streambeds will form over top of the gold deposits.

“Loose-packed” material consists of sand, silt, rocks and gravel which possess little or no natural structural cohesiveness. When you dredge a hole down through loose streambed material, it keeps sliding in on you. Digging through loose-pack can be like trying to dig down through a pile of sand or gravel. The material keeps slipping into the hole. This makes for a much more difficult sample hole if the material runs deep.

Sometimes, loose material is resting on top of a hard-packed streambed and must be moved out of the way first, before the hard-pack can be properly sampled.

When you dredge a test hole through hard-pack, the streambed will generally hold up the wall surrounding the hole. In fact, many of the old-time operations tunneled underneath hard-pack. This was/is called “drift mining.” Sometimes they even tunneled directly under active rivers!

It is also important to be able to identify tailings. Tailings are easy to identify, as long as you understand how streambeds are mined. Tailings do not look either like hard-pack or loose streambed material.

When hard-packed streambed is being mined, the cobbles and boulders (i.e., rocks that are too large to pass through the recovery system) are tossed back onto a pile behind the production area. As the production area moves forward, piles of boulders and cobbles are left behind in place of the original hard-packed streambed. Sometimes, sand, silt and gravel that is processed through the recovery system is dropped on top of the cobbles. Later, winter storms also wash sand, silt and gravel across the top of the cobbles. The sand, silt and light gravel then filters down and fills in most of the space between the cobbles. Therefore, tailings usually end up as loose stacks of cobbles with sand, silt or light gravel filling the spaces.

A large flood-storm may wash the tailing-cobbles away at a later time and redeposit them into a newly-formed hard-packed streambed. Or, as in the case of the 1964 flood in northern California, rather than wash away all of the cobbles, many of the piles were leveled off by the storm, and a new layer of hard-packed streambed was deposited directly on top of the loose cobbles. When we dredge sample holes in those locations, we usually find a hard-packed streambed on top of the tailings (loose cobbles). If gold traveled in that part of the waterway, we find it concentrated at the bottom of the hard-pack, sitting on top of the tailings. Underneath, we find loose cobbles with sand and silt between them. These usually go all the way to bedrock. We find very little gold on bedrock, because it has not yet been directly exposed to a major flood storm since being mined.

  

Some waterways will have several different natural streambed layers, each with its own concentration of gold resting on top of the layer or bedrock below. Different streambed layers usually exhibit a different color and compactness. The “contact-zone” between the layers is generally pretty easy to spot. Within the contact zones between layers, and on top of bedrock, is where you will find most of the gold concentrations. Those areas, then, should be the target of your sample holes.

As shown in this following video segment, sometimes the highest-grade deposits will be found up on top of a layer of hard-pack in the streambed:

Seldom will you find rich pay-streak gold deposits associated with loose streambed material. However, it does occasionally happen. These occurrences are almost always the result of winter storms, and the resulting run-off, eroding away a hard-packed streambed along the bank — which washes the gold down into the waterway to rest with the loose material.

There are areas in Africa where streambeds consist entirely of loose gravels – sometimes which carry substantial amounts of gold and/or gemstones. But this is an exception to the rule.

Effective sampling is the key to a successful mining operation. And, when you are sampling, you should be looking for hard-packed streambed layers. Watch for the gold concentrations along the bottom of these layers, because that is where you will usually find them.

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