By JIMMY SIERRA

In the metal detecting industry, there is a term which has recently been
misused a great deal. This term is:“discrimination.”

 

Metal detectingSome have said that the pen is mightier than the sword, and I am sure that on occasions this has truly been the case. Throughout the ages, man has used words to explain, convince and cajole his fellows about one thing or another. Advertising executives are no exception to the rule; and in their deft hands, a word can become downright dangerous or at least costly to some of us. I am, of course, speaking about the use of the language without explaining the meaning of the terms used.

Every special interest has built into it numerous buzz words. Golfers, tennis fans and fishermen all have special terms familiar to the insider, and metal detector users are no exception. We all get to know these terms as we read articles and talk with the cadre of users. However, there is one term which had been used correctly for a long time, but which has more-recently been misused a great deal. This term is “discrimination.”

Discrimination was originally conceived by metal detector engineers as a means of operating a detector in junky areas; and, by some electronic magic, eliminate or alter the sound of a target which consists of unwanted material and thus increase the amount of good targets for the treasure hunter. This whole experiment was intended to benefit the coin hunters, who were in fact the majority of treasure hunters. When I first started detecting, metal detectors had no such ability and we dug everything. We found a lot of good items, of course; but spent a lot of time doing it. Then along came ground-cancelling, which is a form of discrimination; and our detectors starting detecting deeper and deeper. Along with the added depth came the attraction of these new GEB or VLF units for nails. Not to be outsmarted, the electronic engineers came out with a discriminator for iron trash, then one for other junk items such as pull tabs and foil.

All of these so-called discriminators worked in the same way, by eliminating or altering the sound of an undesirable target. All had the same weakness: The more mineralized the ground, the less they were able to penetrate compared to the al- metal or non-discriminate mode of the detector. Even with the so-called motion discriminator, this still holds true. A GEB or VLF discriminator goes deeper than the old TR discriminators, but not as deep as the all-metal mode when there is increased mineralization in the ground that you are searching.

Ladies metal detectingBut with the advent of meter identification on many detectors, the user was no-longer locked into searching in a discriminate mode with limited depth. He or she could finally search in an all-metal mode if desired and check the meter for probability of target identification. This is where the definition of terms is becoming important and what I have been leading up to. I have recently heard it said that this or that detector is better for prospecting because it doesn’t discriminate, and many a treasure hunter has set aside his or her perfectly good multipurpose unit and bought another unit just for prospecting. I am not suggesting that these new units are not worthy of the task; but in many instances, it was costly and unnecessary to buy two units. First of all, the original unit should be able to cancel the ground effectively; and secondly, the owner must learn the skills necessary to operate it in a prospecting environment. Every company makes such units, and all are capable of finding the elusive gold nugget. The meter should work independently of the all-metal audio signal. That is, you should be able to operate the detector in the all-metal mode and hear every target that the loop passes over. The meter should respond to these targets in some sort of predictable fashion.

Thus the meter really ceases to be a discriminator, but functions in reality as a target analyzer. This is the term I feel is more appropriate. Even though this is visual discrimination, nothing is being eliminated as is the inference when the term “discriminate” is used. Of course, there are limitations to this ability, namely the extent of the mineralization in the ground. The meter is, of course, still working in the discriminate circuit of the detector and has depth capability depending upon the amount of ground mineralization. But it is there when you can use it, and it is a valuable tool indeed.

On a recent trip into the El Paso mountains in southern California with my White’s Eagle, I spent the better part of three days fighting the intense heat and struggling with the enormous amount of metal trash in an old mining area. The two fellows prospecting with me were digging all targets and collected between them enough nails to build a small shed. In about the same period of time and number of targets later, I had accumulated only a hand full of nails, but enough lead and brass for a small arsenal. My point is, there are only so many targets a day a human body can dig. The more probable gold nuggets there are (lead, copper and brass are all probable nuggets), the more gold will be dug. The more nails and iron trash you must dig up, the less the odds of digging a nugget. It is an odds-game from the start. I ended up with a single 2.7 pennyweight. nugget on the third day, not from skill, but from better odds and some luck.

One of my good friends has used a Whites 6000Di/pro during the past two years, gleaning gold nuggets from the tailings and gullies of north-central California. The area he works was heavily populated with miners, and the iron trash is extensive. He works with a smaller loop to get in-between the trash, and has told me he never digs a target unless his meter indicates the possibility of a desirable target.

On the other hand, you must always consider that tiny nuggets can drop into the iron range (meter reading), and thus I do recommend digging any dubious signal. When in doubt…DIG.

Just so you don’t think all is peaches and cream, there is a minus side to every method. Because of the extreme mineralization in some locations, there will be times when you will not be able to rely upon your meter or display screen. You will know this because your meter will respond to the ground with readings or numbers whether or not a target is there at all. At these times, you will have to dig all targets just as if you didn’t have a target analyzer meter at all.

I learned this the hard way a while back on a trip into the Pinto Mountains near 29 Palms. A group of us with an assortment of units started out early one morning and headed about two hours into the desert for a dry-wash known to produce nuggets. I headed down the wash with my trusty Eagle in tow which had just come from a successful trip to the Sierra’s where my meter ID worked beautifully. In fact, a ¼-grain nugget had registered with a positive dig signal on the eighth or ninth pass. I was a bit cocky, and I broke my cardinal rule: Put down a nugget or two of varying sizes and cover them with some of the local terra firma. Check the sound and the meter to see the response. In other words, know what you are getting into. My friend of the El Pasos came down the gully behind me. I stopped at a number of signals, checked the meter and walked on. A few moments later, my friend beckoned me back. “Check this one,” he said. I did, and it sounded good. But the meter said iron. It was a small nugget of a few grains. I checked my sample nuggets and got the same response. In fact, I had to progress to a half-pennyweight nugget before the reading would not be overridden by the heavy ground mineralization! The gully was full, as should be expected, with much black sand; and it was overriding the nugget response on the meter. The sound was loud and clear, but the meter reading was unreliable. This was one of those instances where you dig everything if you want small targets, or you just settle for the less-frequent larger nugget.

The incessant hot rock can also be easily identified with a meter and not be the bother that some make of it. All this takes skill and practice. Learn to use your detector, whichever one you buy.

Remember, you have to be standing over a nugget to find it!

 

BY GORDON ZAHARA

Several years ago, I decided to devote my time entirely to nugget hunting in northern California, giving up the other methods I was using. Being retired at a relatively early age, I had plenty of time. And so, I spent approximately six hours a day, four days a week, during the next two years, learning by trial and error what equipment to use, how to use it properly, and where to go to be the most effective with it.

After numerous requests, I have decided that this web site would be an appropriate place to pass along some of the helpful tips I’ve learned–things that will make it easier for someone who wants to get started, or improve their methods in the rewarding activity of detecting for gold nuggets.

Also, during the past several years, technology in the field of nugget detecting equipment has been improving rapidly. With the advanced technology and capabilities they put into the new designs, a prospecting metal detector (one designed specifically for finding gold nuggets) is capable of finding a piece of gold at greater depths than ever before, and some people can detect pieces weighing as little as 1/10 of a grain with ease.

When deciding on the metal detector of your choice, a few good points to remember are:

1) Seek out friends or other qualified individuals who can answer questions and show you how to use metal detectors designed for gold nugget hunting. Nugget detecting is a specialized field in itself.

2) Find a reputable equipment dealer who has a good selection of prospecting detectors. Note: All metal detectors have the capability of finding gold nuggets. But a detector designed specifically to find gold will give you a far better edge in your quest, make it easier, and more fun.

3) Have your friend or dealer bench-test various detectors for you. This will allow you to compare the depths and capabilities of the various detectors. (Please keep in mind that the degree of mineralization in the soil you’ll be working is going to affect the detector’s sensitivity and therefore your ability to find the same sized pieces. You won’t be able to find them at the same depth in the soil as you’re able to in the air.) Therefore, it is also of extreme importance to choose a detector that is going to be able to handle the heaviest mineralization possible.

4) Another helpful tip to use when selecting your detector is to know that in recent years we have generally found that the higher the operating frequency or kilohertz (khz) of a detector, the smaller the gold that can be found with that detector.

5) Upon choosing your new detector, make sure your dealer instructs you in the use of your new machine. This can be done in various ways. The best ways are by either using a test-patch (area with gold and other metal targets buried in mineralized soil), or by having the dealer take you to a gold bearing area and give you hands-on training with your new detector. You should never test a detector solely inside a building. Because the results will not be accurate, due to the materials in the walls and floors. In addition, exclusive testing there will result in your finding yourself alone in the field with your new detector and not knowing how to effectively make use of it. Because a detector’s response in the field is completely different from a “bench test.”

The following is a list of some of the metal detector accessories and tools you will need to be successful, as well as the purposes they serve to facilitate your quest:

1) Earphones: A necessity for nugget hunting. You will lose 80% of your detector’s sensitivity if you try to detect without them. They should be well padded, allowing for long periods of usage. It is also a good idea to have some type of built-in booster which adds to the depth capabilities of your detector and enhances the metallic sound of the gold.

2) Coil Cover: A small item, but quite important. It will protect the bottom and sides of the coil and give it a much longer life.

3) Digging Tools: There are many types to choose from, so find the one, or ones that best suit you.

4) Plastic Cup: To be used to separate a target from the soil by process of elimination. It should be about 4×3 inches, and slightly flexible.

5) Rake: Any type of heavy-duty rake will work. The rake is often used to eliminate soil from a paying area, a few inches at a time. This enables an electronic prospector to find deeper nuggets. Using the raking system, I have found many nuggets that I would have otherwise missed. Note: Gold nuggets are often found in patches. So where one nugget is found, many more may be located.

I feel that the above items are the most important accessories you will need. There are a great number of other products on the market, and you can determine if you need them or not after you have been detecting awhile.

Where to hunt? The best answer I can give to this question is, hunt anywhere that gold nuggets have been found in the past. In other words, any gold bearing area. Almost any research books on past mining operations and other related topics can help you locate prospective metal detecting areas. After you have located an area, you must make sure that it is not private property or already under mining claim.

Many people have trouble finding areas to metal detect for nuggets. If this is your problem, you might consider joining a mining organization.

Here are a few pointers that may help you after you have found the areas you want to metal detect.

For Desert Areas, check the following:

1) Exposed Bedrock: Gold can usually be found on bedrock, or in exposed crevices.

2) Washes: Desert gold is moved by flash floods, which create washes that may be gold bearing. The banks of washes also sometimes pay well, with nuggets that are in the process of being washed down by the infrequent flash flooding.

3) Old Dry-washing Tailings: Dry-washing equipment misses gold many times when the dirt is screened into the machine. A dry-washer does not separate wet dirt well and the gold can often flows right out into the tailings.

4) Any other desert areas where prospectors have found gold in the past. Remember–GOLD IS WHERE YOU FIND IT–AND WHERE OTHERS HAVE FOUND IT!

For Mountain Areas, check the following:

1) Rivers & Streams: Detect all exposed bedrock on the sides of rivers and streams.

2) Old Mines: Look through tailings piles and around old stamp mills. Check roads that were used for hauling ore. Caution: Do not enter any mining tunnels. These can be extremely dangerous.

3) Hydraulic Areas and Ancient River Channels: Metal detect all exposed bedrock. Look under rock piles (watch for snakes!) Check areas where old sluice boxes were used. I’ve found that gold can be anywhere in a hydraulic area, so be sure to search these areas very carefully.

For the beginner, desert metal detecting should be considered as an excellent learning area. Since the desert has mostly flat terrain and very little mineralization in the soil, a new metal detector can be mastered more-easily here.

My last tip is to keep up-to-date on new metal detectors and accessory equipment. The metal detecting industry now realizes that the electronic prospector who hunts for nuggets is a viable public. New and even better equipment is on the horizon for us out there.

I hope this article aids you in getting started detecting for gold nuggets.

The following is a list of recommended books that can provide further information on nugget hunting: 1) “Finding Gold Nuggets With a Metal Detector,” by Jim Normandi. 2) “Follow The Dry-washers,” by Jim Straight. 3) “Magnificent Quest,” also by Straight. 4) “Modern Electronic Prospecting,” by Lagal and Garrett and 5) “Successful Nugget Hunting,” by Pieter Heydelaar.

 

By David R. Toussaint

Professional Gold Hunter’s Strategy Leads to Pockets of Gold

 

PrestonPreston poses with his collection which came from a pocket in northern Nevada.

A professional electronic gold prospector in Arizona has developed a gold-hunting strategy that has led to the discovery of more than 100 ounces of gold during the past few years. Preston Vickery, 42, of Kirkland, Arizona has used his gold-hunting strategy, which he calls “pocket hunting,” to find in-place gold in hard-hunted areas that have only frustrated other electronic prospectors. Now he’s ready to share his strategy with the world:

“Most others are stuck in the (placer) nugget mode,” says Vickery about other electronic prospectors. “They should be doing the whole area when they hunt for gold. You do placer and you do hardrock hunting.” Vickery has the right credentials to create his own method of gold hunting. While not a graduate of any mining school, Vickery got his education in prospecting from real-life experience and a family tradition. He’s been a professional gold prospector since his early-20’s and has also worked every facet of mining. “I’ve made a living,” Vickery says modestly. “I haven’t gotten rich, and I haven’t been on welfare.”

You might say prospecting is in the Vickery blood. Preston’s father was also a professional gold prospector and miner. The elder Vickery taught his son all he could about prospecting, including the geological indicators associated with gold formations. Now in his 90’s, Preston’s father is too old to get out much, but he still has a few things to teach his son about gold prospecting. Tracing the Vickery bloodline back even further, Preston’s grandfather was also a professional miner and prospector. Grandpa-Vickery spent much of his life working in lead and gold mines, and he wasn’t shy about passing on his knowledge to his son. Thus, Preston’s grandfather started a family tradition that has created three generations of prospectors and miners.

Now, when Preston goes prospecting, he uses the accumulated gold-hunting wisdom of three generations. Preston has been fairly successful over the years, but his gold-finds began to dwindle during the mid-1980’s. Most of the good nugget-hunting areas were being hunted-out, and it became harder and harder to make a living as a prospector.

It was about that time that Vickery bought a Fisher Gold Bug metal detector. “Once I saw what a Gold Bug could do, it wasn’t long before I bought one,” he remembers. One time out on the Arizona desert, Vickery watched a famous nugget shooter amaze a group of electronic prospectors. This top-notch nugget shooter waited until the other prospectors in the group were satisfied that a nugget patch they were hunting was thoroughly cleaned out. After asking permission, he swept the patch one more time with his Fisher Gold Bug, finding another two or three small nuggets. “He was the best I’ve ever seen,” says Vickery.”He worked quickly but thoroughly. He taught me how to clean out a nugget patch.”

Even though Vickery learned how to clean out a patch in the late ’80’s, fewer and fewer nugget patches needed cleaning out. It seemed like every place the old-timers found gold had already been hunted to death. Vickery could spend all day hunting and only find one or two nuggets. These finds might excite a weekend prospector, but they were not enough for someone whose livelihood depends upon finding nuggets. There had to be a better way. Contemplating his predicament, Vickery began to piece together things his father had taught him and things he had learned himself. The result was a new approach to gold hunting that he calls “pocket hunting.”

Using this new method, Vickery’s luck began to change; and he soon found three nice pockets of gold. What is a “pocket” of gold? “To understand this, you must first understand how gold ‘makes,’” says Vickery. The story begins thousands, maybe millions, of years ago. First, the earth splits, forming cracks and fissures. These fissures form an intricate structure of veins that sometimes reach a hundred miles across the earth’s surface. A second movement of the earth, such as an earthquake, is required to create the right conditions for gold to form within this system of cracks. If this second movement occurs, an “intrusive” can be formed, allowing chemicals and minerals to enter the crack. Gold forms if the right chemicals and minerals are present in the right concentrations. “Gold is just a quirk in the way nature works,” says Vickery. “All it is, is a big break in the earth’s surface. These cavities are usually cracks that develop into veins. Small veins sometimes pocket-out into kidneys. These fill up with solutions and sometimes gold is formed.”

These “kidneys” or “pockets” along the cracks in the earth are what Vickery looks for when he hunts for gold. He says that it is possible to predict the location of these pockets by visualizing the structure of cracks in which gold has a chance to form, or “make,” as Vickery says. These pockets of hardrock gold do not usually contain as much gold as the main vein that the old-timers mined, but 30 or so ounces of gold is nothing to sneeze at.

These cracks in the earth’s surface, which develop into veins, usually form along parallel lines, all traveling in roughly the same direction. To find the pockets of gold, Vickery extends the boundaries of his search area away from the historical diggings. He tries to visualize the system of cracks that gave the gold places to “make.” Many small pockets of gold could have formed along this system of cracks, sometimes up to 500 or more feet away from the original outcropping. “You go in the area where gold has already been found. Then you look for the way the structure (of veins) is running,” Vickery says. “You just try to put yourself in the area where gold has a chance to’ make.’”

“Smaller veins that formed parallel to the main vein were difficult for earlier generations of miners to find, especially without metal detectors,” Vickery says. The old-timers followed a vein by digging. If they did not see any more gold in their pan, they gave up and stopped digging the vein. If the vein picked up again farther on, or if a splinter vein made a small pocket of gold away from the main vein, the old-timers had no way to find it. “The old-timers would have dug along the vein for some distance to see if it would ‘make’ again,” Vickery explains. “The old-timers couldn’t get all the tiny splinter veins. Sometimes they were too far away. They didn’t have the technology to find them like we have today.”

Using his metal detector, Vickery found a nice pocket of hardrock gold on a prospecting trip to northern Nevada. But the trip did not start out on a happy note. Two days of hunting a well-known area near some historical diggings had produced only a few small nuggets. Putting his pocket-hunting strategy into service, Vickery found a 30-ounce pocket of in-place gold just a couple-hundred feet away from the hard-hunted old-time diggings. About four feet deep, the pocket had formed along a smaller vein that ran parallel to the primary vein which the old-timers had mined. Hidden four feet below the surface, the pocket gave off a strong signal when he passed his detector coil over it.

So what is the first step when pocket hunting for gold? The first thing Vickery does when he starts hunting an area is to climb a hill. Using binoculars, he studies the entire area and draws a map with reference points to provide bearings while he hunts. Next, he looks for gold indicators, cubes or clods of iron oxidation that form an “oxide zone” around the historical diggings. Patterns in the oxide-zone, like strings of red earth, that suggest a crack in the earth where iron formed, can also indicate a vein. Often times, if iron formed in a crack, gold also could have formed in another nearby spot along the same crack.

In particular, Vickery looks for any place that the red oxide lines shifted, forming a broken line. This shift could have created an intrusion that allowed gold to form a pocket within the crack. Visualizing the system of veins in the earth, he starts hunting, by searching right on top of the main vein, tracing about 400-to-500 feet to see if it picks up again in a spot unknown to the old-timers. If it doesn’t, he then drops downhill about 20 feet from the main vein and begins hunting in a line parallel to the main vein, now attempting to discover any pockets in splinter veins. Again, he hunts to a distance about 400-500 feet away from the original diggings. If his detector remains silent, he drops down another 20 feet and repeats the process.

If he finds any gold nuggets while searching, Vickery marks the spot and searches uphill to find the in-place pocket where the nuggets originated. If he finds a concentration of gold nuggets, he carefully works out where the concentration begins, where it occurs in the highest concentration and where it thins out. Then, using the edges of the concentration as two points of a triangle, he knows the third point of the triangle will be somewhere directly uphill where the nuggets originated. So he begins searching directly uphill from the highest concentration of nuggets. Vickery says he picked-up this method of triangulation in “Gold Canyon,” a novel by Jack London.

Pocket hunting for gold takes considerable concentration; it isn’t as easy as simply locating an old-time mining operation and swinging your metal detector around. You have to keep your hopes up, and not let yourself become discouraged. Pocket hunting provides the electronic prospector with a strategy for gold hunting that can result in more than an occasional placer nugget.

 

By Dave McCracken

You have a substantial prospecting-advantage with a modern gold detector!

Dave McCracken

 

 

woman with a gold nuggetI highly recommend The Fundamentals of Electronic Prospecting be read before reading this article.

All the rules of placer and desert geology apply to gold nugget hunting, and this knowledge should be utilized to establish where gold deposits and nuggets are most likely to be found.

Particular attention should be paid to locations which have little or no streambed or other material present, so the detector’s coil can search as closely as possible to bedrock or false bedrock layers. Also, exposed tree roots along the edges of the present streams, rivers and dry-washes have been proving successful, especially along the smaller tributaries in the higher elevations of known gold country.

Some of the most productive areas for electronic prospecting in the dry regions are in the near vicinity of old dry-washing operations. The old-timers were only able to make dry-washing work in very high-grade areas. They seldom recovered all the high-grade gold out of an area, because they did not have the means or equipment to prospect extensive areas. You have a substantial prospecting-advantage with a modern gold detector. Natural erosion over the years has likely uncovered more high-grade in the immediate area, or concentrated other spots into new high-grade gold deposits.

When prospecting old dry-wash workings, it is always worth a little time to rake back some of the old tailings piles and scan them with your detector. Dry-washers, today and during the past, almost always used a classification screen over the feed area. The screen was commonly around half-inch mesh. An operation shoveling onto the screen at production speed in dry high-grade gravel might have missed larger nuggets as they rolled off the top of the screen. Sometimes, when working a layer of caliche, if the material was not broken-up well enough, it would roll off the screen with nuggets still attached. A metal detector reads out strongly on these kinds of targets. Make sure to ground-balance to the tailing pile. One nice thing about prospecting in these tailing piles is that they usually are not filled with iron trash targets.

When dealing with natural streambeds above the water, you generally do not find too many other reading metallic objects besides gold, unless the spot which you are scanning is near an inhabited location, like a park or an old dump. So it is reasonably safe to dig any target that gives off a metallic reading in a streambed.

However, some locations have lots of trash and small iron targets. Sometimes, iron targets seem to accumulate heavily in the same areas as gold. This presents a big challenge! Once you have been scanning a particular area for a while, you will gain an understanding of how much “trash” (metallic objects of no value) exists within the vicinity. With some experience on gold objects, you will learn to distinguish the different tone changes between most gold objects and most trash targets. Pay particular attention to the very faint readings, as is often the case with natural gold targets.

One of the main keys to successful electronic prospecting is to slow down your sweeping action. You cannot do it fast like when hunting for coins. You almost have to crawl across the ground. Remember, you are listening for even the faintest whisper of a sudden increased threshold hum. A gold target may sound like a coin—only a quieter signal.

Different types of detectors have special non-motion or pinpointing settings which allow the coil to be moved very slowly and still pick up targets. This means you are able to slow down your sweep to almost a standstill and still hear a target as the coil moves over it. On the other hand, these settings may be too sensitive to use for nugget hunting on some detectors, depending upon field conditions and how fast you are sweeping. When in doubt, experiment while using a test-nugget on or in the ground you are searching.

Another important point is to overlap your coil sweeps. The area covered by the search-field under your coil is similar to a triangle. Directly underneath the coil, the search area is about the same size as the diameter of your coil. The search area becomes narrower as it penetrates the ground further away from the coil.

However, the size of this triangular search-field is not constant underneath the coil. It changes as mineralized conditions change in the ground below your search coil. If you do not overlap your search strokes, you can leave as much as 50 percent or more of the area below the search coil behind, without being adequately searched.

Image 1

You have to use your own judgment about how to discriminate between which targets to dig, and which to leave behind. This comes with practice and experience. Discrimination of any kind, whether by electronic circuitry or the audio sounds given off by the target, has limited accuracy. The depth of a target and the degree of ground-mineralization in that particular location can confuse any discriminator. In some places, you will want to dig every target. In other places, where there is lots of trash, you may find it more productive to discriminate your targets by sound and/or in combination with electronic discrimination features on your detector. In this case, you have to balance the need to leave some small pieces of gold behind, with not wanting to dig a bucket full of trash and valueless iron targets; and therefore, less gold.

When in doubt, dig! Or at least toss your sample nugget down and get a comparative reading.

With lots of practice in the field, you will eventually reach the point where your metal detector is like an extension of your arm—like an extension of your perception and knowingness. You will gain the ability to look down into the ground and have a pretty good idea of what is there.

Big nuggets are generally not too difficult to find. In most areas, however, there are hoards of smaller gold targets in ratio to each large nugget found. Small pieces of gold are your bread and butter! Most gold is small gold, but it has to be large enough to be worth your while. Some of the modern gold detectors will pick up pieces of gold so small that you could be finding them all day long; and at the end of the day, not have accumulated very much gold by weight. In this case, you may want to move to a different area.

Just like in other forms of gold mining, electronic prospectors have to set standards for themselves. Someone pursuing the activity to make money will be motivated to recover volume-amounts (by weight) of gold. Another person pursuing electronic prospecting as a part time activity may receive his or her best thrills by recovering the smallest-sized targets.

One interesting development in the electronic prospecting field, which I have not seen happen in other gold mining activities, is the tremendous emotional success gained from finding extraordinarily-small pieces of gold. Normally, in gold prospecting, we get excited to find a big nugget or a rich deposit. These are easy to locate when scanned over by a metal detector. The big challenge with a metal detector is in locating the smaller pieces. Experienced prospectors know that if they are finding the small pieces, they will easily-find the big pieces.

When scanning, keep your coil as close to the ground as possible. It takes a coordinated arm and wrist-action to keep the bottom of the coil parallel and close to the ground throughout the full sweeping action. Allowing the coil to move one or two inches away from the ground during the outside of a sweeping motion will also reduce depth-penetration by one or two inches. This will certainly result in lost gold targets. You have to practice keeping the coil close to the ground. Shorter sweeps is usually the answer.

Sometimes it helps to kick rocks out of the way, or use a garden rake to remove multiple smaller obstructions before you search an area. This allows you to keep the coil close to the ground with minimum obstructions.

During your prospecting activities, it is possible that you may find occasional targets which could potentially be classified as artifacts. The Archaeological Resources Protection Act defines just about anything you might find as a “protected” artifact. There are criminal penalties for disturbing or removing artifacts. What constitutes a protected artifact is primarily up to the judgment of local bureaucrats. Searching for natural gold targets is legal. Messing around with old junk and trash may be illegal. Sometimes, it is better to just leave old items where they lie. You will have to decide.

The main suggestion I commonly give to beginners about electronic prospecting is to not give up. With practice and by working in the right area, you will surely find some gold!

PINPOINTING

When you do have a reading target, its exact position in the ground should be pinpointed. This can be done by noting when the detector sounds out while scanning over the target in fore and aft and left to right motions. A steel or iron object can be often be distinguished by noting the size and shape of the object during the pinpointing process. Sometimes trash objects are large and/or lengthy in size.

Sometimes a stronger-reading target will seem to cover a larger area than it actually does. If you are having trouble getting an exact location, continue to lift the search coil higher off the ground while scanning with an even back and forth motion. As the coil is raised higher, the signal will become fainter; but the position of the metal object will sound-out at the very center of the search coil.

PINPOINTING WITH THE GOLD PAN IN WET AREAS

Once you have pinpointed the exact position of a target in an area near water, one way of recovering the object is to carefully dig up that portion of ground, using a shovel or digging tool, and place the material in your gold pan. Here is where a large plastic gold pan comes in real handy. Be careful not to cause any more disturbance or vibration of the streambed than is necessary while you are attempting to dig up a target. It is possible to miss the target on the first try and cause it to work further down into the streambed because of its greater weight in the wet environment. Sometimes you can lose the target, and not be able to locate it again with the detector.

Sometimes the ground is hard and needs to be broken up or scraped with a small pick. Keep in mind that a sharp blow from a pick can destroy a coin or disfigure a gold nugget, reducing its value. Digging and scraping is better than pounding, if possible. In hard ground, sometimes it is easier to loosen the material up and shuffle it into several small piles. These can then be flattened out and scanned to see which contains the target.

Once you have dug up that section of material where the target was reading, place it in your plastic gold pan and scan it with your detector. If the contents of the pan do not make your detector sound-out, scan the original target area over again. If you get a read in the original location, pour the contents of the pan neatly into a pile out of your way, pinpoint the target all over again, and make another try at getting the target into your gold pan. Continue this until you finally have the target sounding out in your pan. If you cannot see the target, and water is immediately available, pan-off the contents until the target is visible.

There is a good reason why you should not ever throw away any material from the target area until after you know for certain exactly what the reading target is. If you are looking for placer gold deposits and it happens that your detector is sounding out on a gold flake or nugget, the chances are pretty good of additional gold being present in paying quantities within the material which has been dug out of the hole, even if it does not sound-out on your detector. Remember, small particles of gold often do not make metal detectors sound-out. Therefore, the possibility exists that there could be hundreds of dollars worth of gold in a single shovelful of material not tightly-concentrated enough to cause your detector to sound-out. So wait until you have seen the reading target before you start throwing any material away.

If you dig for a target and then cannot get any further reads on the detector from either the pan or in the original target area, quickly pan-off the pan’s contents. There is always a possibility of a concentrated gold deposit which is no longer concentrated enough to read-out on your detector. In this case, you are most likely to have some of the gold deposit in your gold pan, which will quickly be discovered when you pan off the contents.

There is also another reason why you save the material from a hole until you have recovered your target. Because of the shape of a gold pan, and depending upon the size and shape of the coil you are using, if the gold target (especially a small target) ends up in the bottom of your pan, your coil may no-longer be able to scan close enough to the bottom of the pan to sound-off on the target. Because of this problem, gold pans have limited workability as a pinpointing tool in electronic prospecting. Sometimes, you can have better luck scanning the bottom-side of a gold pan.

DRY METHODS OF PINPOINTING

There are several popular methods of pinpointing reading targets in the dry regions where water is not available for panning. Some prospectors use a plastic cup. Material from the target area is scooped up and passed over the coil. If the contents of the cup do not sound-out on the detector, the target area is scanned again until the target is located. Take another scoop, pass it over the coil for a signal, and repeat until the target is in the cup. Then pour some of the contents into your hand. Pass the cup over the coil, then your hand, until you locate the target. Put the rest away in a neat pile, and repeat the process until you recover the object.

One important point to mention is that most search coils have equal sensitivity to targets both above and below the coil. In other words, during pinpointing, you can pass material over top of the coil and obtain the same results as if you turn the detector upside down and pass the material across the bottom of the coil.

Your handy magnet can be a big help when you are having difficulty finding a faintly reading target. Sometimes it is just a small piece of iron.

There is also the hand-to-hand method of pinpointing a target. You can reach down with your hand and grab a handful of dirt or material. Pass your hand over the coil to see if you are holding the target. Continue until you have the target in one hand. Then pass half the material in that hand to your other hand. Use the coil to find which hand has the reading target. Discard the material from the other hand and pass half the material from the reading hand to the second hand, again. Keep up the process until you only have a small amount of material in the reading hand. Carefully blow off the lighter material to locate the target.

Another procedure is to grab a handful and pass it over the coil as explained above. Once you have a reading handful, toss it in a pouch for later panning.

Some prospectors prefer to sprinkle a handful of reading material slowly on top of the detector’s coil. There are different ways to do this. One effective way, which requires some practice, is to sprinkle material over a slightly slanted coil while you vibrate it so that material slowly sweeps across and off. When the target drops onto the coil, the detector will sound-off with a distinctive bleep. Then, all you have to do is gently blow the dirt off the coil, or recover the target from the top of the pile where the material is landing. This method is nearly impossible in wet material.

One important thing about using your hands to pinpoint and recover gold targets, is that some of today’s most sensitive high frequency gold detectors react to the salt (mineral) content on or in your hand. When this occurs, your hand will give a reading when passed over the coil by itself, sometimes even a strong signal. This makes hand pinpointing methods more difficult. In this case, the plastic tray or cup works just fine, or the method of pouring material onto the coil.

If you find a gold target, be sure to scan the hole again. Sometimes it is worth doing a lot of digging and/or raking, with alternate scanning of the immediate area. Gold targets almost never travel alone! I have seen dozens of gold flakes and nuggets come from within a one-foot square area on bedrock. Many times!

HOT ROCKS

Sometimes you get soft or strong signals from your metal detector when the coil is passed over rocks which contain heavy mineralization. These rocks are called “hot rocks.” This needs to be clarified. It isn’t necessary for a rock to have an extraordinary amount of mineralization to sound-off as a hot rock. It just needs to have more than the average ground which your detector is ground-balanced to. The opposite of this is also true. A rock containing less mineralization than the average ground will change tone on a detector in the opposite way. These are called “cold rocks.” A hot rock from one location could be a cold rock in another location containing higher mineralization in the average ground.

Put another way, when your detector is properly ground-balanced to the average ground, it will sound-off on rocks containing condensed heavier mineralization. Often, the signals given off by these hot rocks can be mistaken for signals which might be given off by gold targets in the ground. Some locations have lots of hot rocks. Naturally, since gold travels with other heavy mineralization, you can expect to find hot rocks in the various gold fields.

Hot rocks come in all sorts of colors and sizes. A big hot rock, depending upon the degree of mineralization over the average ground, can sound very similar to a gold target. The same goes for small hot rocks.

Quite often, most of the hot rocks within a given area will be similar in nature, color and hardness, but not necessarily in size. After searching an area for a while, you will know what most of the hot rocks look like. This makes pinpointing targets a little easier, especially when dealing with small hot rocks. When receiving signals from rocks which are dissimilar to the average-looking hot rock of the area, check them out closely, especially when they have quartz. Some of these may not be hot rocks at all, but gold specimens.

If you are finding hot rocks on top of the ground, you will almost always find them buried, as well.

Metal targets gradually lose signal-strength in proportion to the increased distance from the coil. Hot rocks rapidly lose their signal-strength as they are scanned further from the coil. Also, a metal target tends to create a more specific, sharper signal as the coil is passed over. The signal given off by most hot rocks is not as sharp. It is more of a mushy sound which doesn’t have as clear a change in tone-intensity as the coil passes over the target.

When uncertain about a reading target, one way that some hot rocks can be identified is by passing the coil over the target from different directions. If the target only sounds out when being swept from one particular direction, then it is nearly certain that the target is not a gold nugget.

Sometimes, when lowering the sensitivity on your detector a few numbers, the signal given off by a nugget will continue, but weaker. A hot rock signal will quickly disappear by lowering the sensitivity. You can get a better idea how your detector is reacting to sensitivity changes by running it over your test-nugget.

Another test is to slowly raise the coil further away from the reading target as you are scanning. The signal of a metal object will become progressively fainter as the distance is increased. The signal given off by a hot rock will rapidly die away as just a little distance is put between the target and the coil. Most hot rocks in a given area will have a very similar sound, the intensity depending upon size and distance from the coil. Sometimes, you will find that a gold nugget gives off a much sharper signal. But not always. Much also depends upon the size of a gold target, its distance from the coil, and the amount of mineralization interference in the ground that is being scanned.

Each area is different. The hot rocks in some areas are reasonably easy to distinguish. In other areas, it is necessary to dig every signal.

Larger hot rocks are easier to detect. Many can simply be kicked out of the way. It is the smaller pebble-sized hot rocks which create faint signals. In some locations, these signals are so similar to the signals given off by gold nuggets that you have no other choice but to dig them up.

If lots of hot rocks are making it difficult for you in a particular area, you might try experimenting with smaller coils. Smaller coils are more sensitive to smaller pieces of gold. Therefore, the sharpness of the signal over gold targets is also intensified. This may give you the needed edge in distinguishing the slightly-different signals being given off by hot rocks in that area.

Some gold prospectors go so far as to ground-balance over top of a hot rock until it no longer gives off a signal. This will eliminate a large portion of the hot rocks in the area, but it is also likely to eliminate a large portion of the small and marginal signals given off by gold targets. This procedure may work well in areas containing just large nuggets. However, most areas I am aware of have dozens or hundreds of smaller pieces of gold for every larger piece that you will find.

Since cold rocks are made up of a lesser-concentration of iron than the average material which your detector is balanced to, they give off a negative reading signal on your detector. Ground-balancing over a cold rock will cause your detector to react positively to the average ground within the vicinity.

PRODUCTION

Once you find a location which is producing gold targets, you will want to thoroughly work the entire area. This is commonly accomplished by carefully gridding the site. By this, I mean creating parallel crisscross lines on the ground, usually about four feet apart. You can do this by drawing light lines in the sand with a stick. Grid lines allow you to keep track of where you are, and what has already been searched.

If there are obstructions in the producing area (“nugget patch”), they should be moved or rolled out of the way if possible. The smaller rocks and materials on the ground can be raked out of the way. This allows you to keep the coil closer to the ground. In a proven area, this will surely mean more recovered gold targets.

Some areas produce quite well on the surface. Then, by raking or shoveling several inches off the surface and scanning again, sometimes you can find even more targets. I know of numerous small-scale mining operations in many different parts of the world, using metal detectors as the only recovery system. They use a bulldozer to scrape away material which has already been scanned, two or three inches at a time. A layer is removed; the area is scanned thoroughly with metal detectors to locate all of the exposed gold targets. Then, another layer is removed and scanned. This process is done all the way to bedrock. They make good money at it!

I have heard of others doing the same process on a smaller-scale by attaching plow blades to four-wheel drive vehicles. Some even do it using ATV’s!

While hunting over a proven nugget patch, be sure to keep your detector properly tuned all the time. Otherwise, you will certainly miss gold targets.

PROSPECTING OLD HYDRAULIC MINING AREAS

Perhaps the most productive areas of all to prospect with metal detectors are areas which were already mined by the old-timers using hydraulic methods. Many of these areas are left with a large amount of bedrock exposed. This allows immediate and easy access for search coils to get close to old gold traps. Sometimes, the exposed bedrock has been further-deteriorated because of direct exposure to the elements. Once a nugget patch is located, raking away decomposed bedrock sometimes can produce remarkable results.

While searching such areas, pay attention to the color of dirt which covers and surrounds nugget patch. You might discover a pattern. In our area of operation, it is a white powder which often signifies the possible presence of a good spot. Perhaps in other areas, it might also be this white powder, or something else.

PROSPECTING OLD MINING TAILINGS

It is usually possible to find piles and piles of old mining tailings throughout most proven gold-bearing country.

Many of the larger earlier gold mining operations (the ones that were set up to move large volumes of material), concentrated on recovering only the fine and medium-sized values from the material being processed. This meant that the larger material was classified-out so the smaller material could be processed through controlled, slower-moving recovery systems. On the larger operations, classification was usually done either with mechanical vibrating classification screens, or with the use of a “trommel.” A trommel is a large circular screening classifier which rotates and tumbles material through, allowing the smaller classification of materials to pass through the outer screen and into a channel which directs them to the recovery system. The larger materials are passed down the inside of the trommel to be discarded as tailings.

In many of the larger operations, there were no means to recover the larger pieces of gold which were screened-out along with the other large materials. As a result, larger nuggets were sometimes discarded along with the waste material as tailings.

Anywhere you see large tailings piles, especially near the present waterways, it is evidence of a large volume operation where it is possible that the nuggets were discarded with the waste and are likely to still be there. Some large tailing piles still have large goodies inside them, which sing out very nicely on the proper metal detectors. One way to distinguish the right kind of tailing pile to be looking through is there should be a pretty wide range of material sizes in the tailing pile. Tailing piles which consist only of the larger rocks (cobble piles) were most likely stacked there by hand during a smaller surface-type operation.

Scanning tailing piles with a metal detector is proving to be highly-productive in some cases, and should not be overlooked as a possibility for finding nice specimen-sized gold nuggets. VLF ground-cancelling detectors are usually best-suited for this, because tailings almost always also contain a large quantity of mineral content, which is likely to cause interference on a BFO-detector.

PROSPECTING OLD MINING SHAFTS

Even the most experienced cave explorers shy away from entering declining mine shafts because of the dangers involved.

CAUTION: The first thing to say about prospecting in old mine shafts is that they are dangerous! There are different things that can go wrong when prospecting around in such places, one main danger being a potential cave-in. The shoring beams in some of these old shafts may have become rotten and faulty over the years. So it is best not to lean up against or bump any of the old wooden structures situated in old mine shafts. Loud, sharp noises should also be avoided.

Shafts which extend down into the earth on a declining angle are particularly dangerous; because if the ladders or suspension systems are faulty and collapse while you are down inside, you may not have any way to get out again. It is never a bad idea to bring along a caving rope, and use it, when exploring declining-type old mine shafts. Caving rope is different than mountaineering rope in that it is made not to stretch nearly as much. But I suppose, when going down in dark holes, any rope is better than no rope at all!

Another potential danger involved with exploring old mine shafts is encountering poisonous or explosive gasses. Entire mines were shut down because of such gasses—even when they were good-producing mines. These, however, were usually caved in and closed off to prevent unsuspecting adventurers from entering at a later date and getting into trouble.

Before you enter any old mine and start sorting through its low-grade ore piles, or pecking samples off the walls of the mine, it is a good idea to make sure the mine is not already owned by someone else. Or, if somebody does own it, it is wise to get the person’s permission first. There is probably nothing more dangerous in a mine shaft, cave-ins and poisonous gases included, than some old cantankerous miner who catches you, uninvited, in his mine and thinks you are stealing his gold!

There is probably more danger in prospecting old shafts than in any other gold prospecting activity.

After all that, just in case I have not succeeded in scaring you out of the idea of entering old mine shafts in your prospecting adventures, here are a few pointers about how and where you might find some rich ore deposits, or rich ore specimens, with the use of your metal detector:

But first, let me recommend that if you do go into such places, you bring along a buddy and leave another one at the surface with explicit instructions to not enter the shaft under any circumstances, but to go get help in the event that you should get into trouble within. It is also a good idea to let a few others know where you are going, just in case your outside-man doesn’t follow orders and you all become trapped inside.

There are two main sources of possible gold and silver in an old mine:

1) High-grade ore specimens that may have been placed in the low-grade ore piles and left as waste material.

2) High-grade ore which has yet to be mined.

With the exception of the largest production hardrock mines, there is always a certain amount of rock (ore) which has been blasted away from the wall of the tunnel that was not milled and processed. This was because some ore is of such apparent low-grade value that it is not worth the expense to process.

Sometimes the vein being followed into the mountainside was not as wide as the tunnel needed to be in order to progress into the mountain. Therefore, that rock material which was not part of the vein itself, or the contact zone, that looked to be of lower-grade value, was also discarded into the waste piles.

Crushing and milling ore is, and always has been, somewhat of a timely and expensive process. For this reason, a good many mines only processed what appeared to be the highest-grade ore that was blasted from the ore body. The rest was usually piled out of production’s way inside or outside of the shafts.

In the smaller operations, the kind where the ore was crushed and milled by hand and then processed with a gold pan to recover the values, only the highest of high-grade ores could be processed at a profit. The rest was usually laid aside out of the way.

The sorting of a higher-grade ore from lower-grade ore has always been a matter of judgment on the part of the person who was doing that part of the job. And, until the more recent breakthroughs in electronic detecting equipment, sorting needed to be done by eye or by feel (weight). There simply was no other way.

The interior of mine tunnels was often poorly lit with miner’s candles during earlier days, and the air inside the shaft was often foul after the powder explosions used to blast ore from the interior of the mountain. As a result of all this, it is not difficult to imagine that some higher-grade ore was likely discarded as waste material in most mines.

How rich the ore was in a mine will have a lot of bearing on whether or not a present-day prospector will find high-grade ore in the waste piles of that mine. The size of a mine does not necessarily have anything to do with how high-grade its ore was, although it may have a bearing upon how much waste ore will be available to test.

County reports can be looked over to locate the old mines within an area. Many of these reports also include information about the grade of ore being extracted from some of the mines.

When you are testing ore samples from a mine with a metal detector, and you do not come up with any specimens, try a few different piles. If you still do not come up with any specimens, it was probably not a high-grade mine. Try another.

Keep in mind that the floor of a mine shaft is likely to have some iron, brass and other metallic objects which will cause your detector to read-out.

One of the fastest and most effective ways of thoroughly checking out samples of ore is to lay the detector down on the ground or upon a makeshift bench with the search coil pointing upward so individual ore samples can be quickly passed by the most sensitive portion of the coil. The 3-inch diameter search coils are probably best-suited for this kind of work, because of the increased sensitivity, and because there is seldom great need for increased depth-sounding when testing ore specimens.

The most sensitive portion of the search coil is usually located near the center of the coil. It can be easily pinpointed by passing a coin back and forth across the coil while the detector is in tune, and by finding that spot where the coin causes the loudest and sharpest reading. The most sensitive area should be marked brightly with a Magic Marker so it will be easier for you to move ore samples directly past it. It is worthy to note that the top of the coil should have similar sensitivity to targets as does the bottom.

Ground-balancing would probably best be achieved by tuning to the overall ore pile. But, you may need to experiment. A lot will depend upon the grade of ore you are looking for. High-grade gold specimens will require the surrounding mineral to be cancelled out. On the other hand, sometimes high-grade ore is full of fine particles of gold which would not sound-off on a detector. In this case, the high degree of mineralization in the ore specimen might sound-out like a hot rock. Therefore, you would not want to ground-balance out high mineralization. So, depending upon the nature of the ore in a mine, you will need to use your own best judgment regarding the proper way to ground-balance.

Bring along a bucket, canvas bag or a knapsack so you will have something to carry your specimens as you find them.

Both BFO and the VLF ground-cancelling metal detectors can be successfully used to locate high-grade ore specimens. For the individual who is interested in finding a wider range of high-grade ore specimens rich enough to be worth milling on a small-scale for the gold and silver values, perhaps a BFO is the better type of metal detector to be used for the job. This is because the BFO does exceptionally well at picking up highly-mineralized ore. When you are dealing with hardrock veins, high mineralization is a good index of gold being present, especially when you are working with the ore that was blasted out of a previously-successful gold mine. Ore which contains large amounts of locked-in values or lots of fine gold that is thoroughly dispersed throughout the ore is not likely to read-out as a metal on any kind of conventional metal detector, although the high degree of mineralization which usually goes along with such ore probably will sound-out on a BFO-detector as a mineral. So the BFO-detector is handy in finding rich ores which might otherwise be undetectable.

By placing a BFO-detector on its mineral setting and keeping the pieces of ore which sound-out, you can accumulate a lot of good-paying ore. With the use of a BFO as such, the perimeters of ore piles can be scanned first to find a pile that has a lot of mineralization.

Portable rock crushers and mills and processing plants are available on the market. Perhaps by combining these with the use of a good BFO-detector to pick out the highly-mineralized, discarded ore, a small operation could be quite profitable without having to invest the higher costs associated with developing a lode mine from scratch.

LOCATING RICH ORE DEPOSITS

When prospecting around in an old mine with a metal detector, don’t discount the idea of searching the walls of the various shafts to locate rich ore deposits which may have been overlooked by the miners who originally developed the mine. With today’s market value of gold and advanced milling techniques, a small-scale mining operation can be run profitably in ore producing about ½-ounce to the ton in gold values, or perhaps even less. Abandoned mines which will pay this well and even better are scattered all over the west. If a person were really interested in locating a lode mine that he could work at a profit, one way would be with the use of a BFO-detector to prospect the various abandoned mines within the area of his or her interest. In using the BFO to scan the walls of such mines, highly-mineralized ore deposits can be located, samples can be taken for assay, and a person could find the mines having the richer-paying ore deposits. When prospecting like this, it is a good idea to bring a can of spray paint, a pen and paper and some zip-lock bags, so samples can be accurately marked as to where they came from, along with their respective deposits being marked with the spray paint.

If you are not interested in starting up a lode mine, but are just prospecting around for a bonus, again, the VLF detector is good for looking through mineralization and detecting the richest deposits. If, however, you do locate a reading metal inside the wall of a mine shaft with a VLF detector, and you have determined that it is not some falsely-reading mineralization, it could be well worth your while to investigate further. This is because the chances are pretty good that you have located some bonanza paying ore. I know of one highly successful high-grade gold mine in the Mother Lode area of California that is using VLF detectors as its sole method of determining where to blast. At this writing, they have located and recovered millions of dollars in gold during the past two years, in a mine which was failing prior to the use of metal detectors.

MEDICAL

Bring along some mosquito repellent during electronic prospecting ventures. Otherwise, if bugs are around, sometimes it is difficult to put your full attention on listening to what your detector is trying to tell you.

In some areas, you also have to be careful of ticks. Some ticks carry Lyme disease. Some insect repellents will keep ticks off of you. DEEP WOODS, TECNU 10-HR INSECT REPELLENT, and OFF seems to work pretty well. Spread the repellent on your boots, pants and other clothing.

In the hot climates, you should bring along the proper sunscreen and apply it to exposed body parts.

It’s always a good idea to bring along a good first aid kit, and at least leave it in your vehicle in case of emergencies.

Extra clothing and water is also a good idea. You can leave it in your vehicle. You never know…

 

By Roy Lagal

 

Nugget hunting in the desert.The term “nugget hunting” is so ambiguous that no description of it could ever be complete. Countless books have been written about this method of searching. Weekend prospectors generally find their instructions too complicated. By condensing descriptions of target areas and summarizing the easiest searching methods for beginners to use, I offer you instructions that are simple but that employ methods proven successful the world over. Tools you may include:

  • Gold pan or gold panning kit
  • Waders
  • Gold tweezers
  • Rock hammer
  • Small bar
  • Shovel
  • Metal detector (suitable for use in mineralized areas)

The metal detector will unquestionably produce the best results in areas where gold abounds and large nuggets commonly occur, such as the western United States deserts, certain “mother lode” areas, Australia, New Zealand, China, Africa and other parts of the world where sizeable nuggets appear in nature. Fantastic finds with metal detectors are regularly reported.

Nugget Hunting Instructions

An electronic metal detector can be used effectively because gold is conductive and its presence will be indicated.

Unfortunately, so-called “hot rocks” contain an iron mineral content that is either greater than or less than the levels for which the ground-canceling detector has been adjusted. They present a constant nuisance to prospectors because they register as metallic (conductive) on a detector. Calibrated circuits used in modern metal detectors that allow easy identification and rejection of “hot rocks” are an absolute necessity in helping a prospector determine whether a rock contains gold or a predominance of iron. Make certain that your detector is a ground-canceling type that contains these special circuits.

In wet areas, start your search near water.

  1.  Adjust your detector to the magnetic iron content of the area according to manufacturer’s instructions.
  2. Pinpoint your target.
  3. Slip a shovel under the target and place it into a plastic gold pan. If the target is located in a bedrock formation, use your rock hammer and small bar to dislodge it. Then place the dislodged target into the pan for examination.
  4. Check the contents once again with your detector. If a “hot rock” is suspected, use the detector to determine if it is ore. If not, discard it.
  5. When the detector indicates gold is present, inspect the contents visually or follow panning procedures.
  6. When the detector indicates no gold in the pan, repeat Steps 3-5 until the target is located.

Metal detectors used for prospecting will also indicate large concentrations of black magnetic sand. Shovel the sand into your gold pan. Inspect for gold nuggets and save the black sand discards for later separation.

In dry areas, the procedure will vary only slightly. Locate the target with your detector, and dig carefully using your hands or a small tool, while being careful to not damage the nugget.

Metal detector headphones are an advantage in most areas, since small nuggets usually generate only a faint response. It is best to dig and visually investigate all targets unless they can be identified absolutely as “hot rocks.”

Electronic discrimination is a valuable aid but should not be relied upon entirely.

Dry areas with small, loose material make visual identification of targets more difficult. When searching such areas, shovel targets into a plastic gold pan or small plastic cup and check for electronic responses. When your detector indicates that a metal object is in the pan, use dry panning first to reduce contents. Then grasp a handful of the pan’s remaining contents with your hand (which must be free of rings and other metallic jewelry) and pass your hand across the search coil’s detection area. The material can be inspected in the same manner if you use a plastic cup. Make certain your detector is tuned correctly and move your hand containing the material across its coil. Continue until you get a response. Then place the contents which generated the response into another pan to avoid loss of the target.

Cracks and other sections of bedrock where gold may be trapped can be inspected in a similar manner. This is called crevicing.”

In desert areas where medium-to-large nuggets occur, and water for testing them is scarce, the metal detector provides the easiest method of recovery. The introduction of VLF metal detectors has brought with it fantastic success stories. Natural elements continually erode mountains, allowing rich deposits to surface. Once a gold nugget of sufficient size becomes exposed, it can be discovered by a metal detector. These nuggets are rarely detectable by sight alone and the absence of water leaves electronic detection as the surest and most effective method for small-scale prospectors.

Gold is too fine for electronic detection in some areas of the western United States, so dry washing machines or dry panning must be employed for recovery. Almost all areas where gold is now located once contained an original vein or concentration of ore that weathered over the ages into a placer deposit. This means that nuggets may still be present even in areas where the gold has been too fine to register on metal detectors. Presence of such valuable nuggets is continually proved as successful searches are conducted with detectors in the dry washes, arroyos and canyons of arid locations.

Streams can be a valuable source of nuggets. In heavily-mineralized areas where productive mines are located, rich ore specimens are often deposited in streams by natural erosion. All targets should be carefully examined before assuming that one is merely a “hot rock.” Valuable coins can often be found in streams of old mining districts. The silver- producing areas of Mexico also produce large nuggets that can be easily recovered from creeks and rivers. Small streams created by the melting of large glaciers in Alaska and western Canada often contain nuggets easily found with detectors.

Searching underwater for nuggets with a metal detector is often not as profitable as in above-water areas. Considering the small amount of labor required, however, especially in comparison with dredging or panning, underwater exploration can be well worth the time and effort. Search slowly and carefully. Even though metallic junk is usually present in streams and rivers, you pretty-much have to examine all target responses from your metal detector. Hot rocks are present in water just as on land.

Very often, companions of dredge operators use their spare time to search streams for nuggets. Persistence and patience are the keys to success here.

Large nuggets encrusted with a black or dark coating have been found particularly on mountain tops. It is believed that volcanic action or oxidation of other minerals and materials encrusted gold with the black coating.

Such discoveries commonly called “volcanic gold” or “black nuggets” represent a rare opportunity for the prospector, and are almost impossible to locate except by electronic detection.

Literally millions of dollars in gold nuggets are being discovered all over the world. Metal detectors enable gold-bearing areas to be searched in a manner never before possible. It is reasonable to state that more nuggets have already been discovered with metal detectors than were ever discovered in all the old gold rushes. The use of a metal detector will provide the weekend prospector with many enjoyable and rewarding hours of activity, and have the potential to detect riches beyond anyone’s wildest imagination.

Editor’s note: The preceding article is a chapter reprinted from WEEKEND PROSPECTING by Roy Lagal, used with permission of the author and Ram Publishing Company, copyright owners. For further information about the book, contact Hal Dawson, Editor; RAM Publishing Company, P.O. Box 38469, Dallas, TX 75238 (214) 278-6151.

 

By James B. Wright

Learning to interpret sound anomalies on your metal detector.

 

Noise comes to those who would use an electronic metal detector in three different basic forms:
1) Locally generated sounds (such as motors, river rapids, people talking, etc.).

2) Equipment-generated sounds (whistles, squawks, buzzes, etc., from equipment maladjustment or defects).

3) And a third noise, which is the sound of a good piece of equipment operating the way it should.

The counter-measures which must be taken against the first two types of noises should be obvious. Kill the engine, stop the talking or wear headphones which prevent outside noises from entering the ear. And, of course, adjust the equipment properly, or have it fixed, and learn to adjust it properly.

The third type of noise is the good type. It is the noise that is created when a good instrument is set up right and working most-efficiently. This noise is a “frying” sound, kind of like rain on a quiet lake, the wind through the pines, a gentle rapid on the river or a crowd at a ball game. It is a good, clean steady hiss. On a meter, it may be a steady deflection of 25-40% of full-scale.

Unfortunately, you cannot have sensitivity without this type of noise, simply because noise is built into all physical processes and all of nature.

What is “noise” as used in this context? One good example is the sound you get from your television set when it is tuned to an unused UHF channel. This is when you see snow on the TV screen. What you are seeing and hearing is the composite of a large number of random electrical impulses, all continuously being generated by the very atoms which make up the television, as well as those which make up the earth, the atmosphere, the sun and the rest of the cosmos. This is the sound of Nature doing her thing!

So, what’s the point of all this?

When you send a signal into the ground and try to detect a response from bits of gold, or from other types of deeply-buried chunks of metal, you are usually dealing with a very weak return-signal amid a sea of pre-existing natural “noise.” The detector must identify and amplify the desired signal and try to discriminate against the unwanted noise.

This is where the user becomes a part of the detection system. Because human hearing is able to pick out signals buried in noise better than any piece of electronic gear (except for certain radar equipment which is gawdawful expensive).

Why then must we not only tolerate noise but appreciate it? Because, if your equipment is so sensitive that it will sense the intrinsic “noise” of Nature, it will sense an equally-weak signal from your target. If your detector sounds-off on hot rocks or black sands, it is alive and well and doing its job.

Your job is to learn to hear and interpret the anomalies in the noise, the “whisper” that is just slightly different, the smallest change in the pitch of tone.

This is what weeds out the expert from the rest of the pack. He (or she) is like a good sonar-man, picking out the submarine while ignoring the chatter of the whales, the fish and the other noises of the sea.

 

BY J. CHARLES COX

“A man so finely tuned to the wavelength of gold and precious stones,
he might just as well be a magician!”

 

During my recent visit to Happy Camp, California, I had the pleasure of being introduced to Jim Swinney. Jim is one of the old breed of mining men and, as such, is a wealth of information. Jim and I talked in his home, where he showed me his specimens of opal, jade, crystal, and gold.

“I started rock-hounding when I was nine,” he said, with an easy grin. “I’ve been at it ever since. One of my relatives was a geologist and when I’d go to the field with him, he’d teach me to identify the different rocks. From there, it was a natural process to become a prospector and jewelry maker.”

I looked across the room at his display case, where multicolored opals bounced sunlight in my direction.

“Did you find those around here?” I asked.

“No. Those are from my opal claim in Nevada. Some of that jade is from this area and most of the gold is too. That’s only a small part of what I’ve found. Some of it I’ve made into jewelry, some of it I sell, and some is in a safe deposit box at the bank.”

“It must be an interesting way to make a living, “I said.

Jim laughed. “It’s interesting all right, but I work for the Forest Service to keep beans on the table. I retire in two more years and between my retirement, prospecting, and being a mining consultant, I figure I’ll do okay.”

“What kind of mine consulting?” I asked, sitting back on the comfortable couch in his living room.

“Gemstone mines, mostly. I go in and tell the owners if I think the claim is worth working or if the mine is safe enough to work, and how to go about getting the gems without damaging them.”

“So you don’t consult on gold mines?”

“Oh yes, but I specialize in gems. I have a friend who’s a gold mine specialist, he does most of the work around here.”

“Is there any pet peeve that you have about the ‘New Age’ prospectors that you want to share with our readers?”

“Yes, now that you mention it,” he said, getting up and going over to the display and taking out a white rock laced with red veins. “I’ve seen inexperienced prospectors pick up a specimen and either lick it or put it in their mouth to bring out the color. They don’t know what it is, or what’s on it. Now if they were to do that with this rock, they’d be dead before help could arrive. This is natural arsenic.”

We talked a while longer, then decided to take our detectors out and stir up a little gold. On the way, Jim told me that Happy Camp was not only surrounded by old hydraulic mining areas, but was actually built on one.

“One woman found a 3/4 ounce nugget by the airport,” he said, as he drove to the place he wanted to check out.

We parked and walked up a medium steep grade, pausing often to let me catch my breath. When we had reached the spot and before I could tune up my detector, Jim said, “Watch it, you’re about to step on that nugget!”

“Nugget?” I asked looking around. “What nugget?”

“This one,” he answered, as he bent down and picked it up.

He put the sub-grain nugget in my hand and said “Look, there’s another one.”

“What are you, a magician?” I asked

He found three small nuggets without even turning his detector on. To say that I was amazed would be an understatement!

Yes, we all found gold that day; and at the truck when we were getting ready to leave, Jim came strolling up with an unusual rock in his hands.

“You carry that all the way from the bottom of that gully?” I asked with a grin.

“You bet! It’s white jade and easily worth a hundred dollars.” “You are a magician!” I said

Summary: I believe that Jim Swinney is one of the finest men that I’ve ever had the pleasure to meet. As a prospector, mining consultant, jewelry and custom knife maker, few are his equal. So, should you happen to need any of the above, or if you’re out in the hills around Happy Camp and see a man with iron-grey hair, ask your questions. Then close your yap and listen close. You’ll surely learn something.

 

By Denise Brown

“A long time treasure hunter turns to nugget hunting for some adventure.”

 

Frank "Midas" MasleySearching for tiny, elusive gold flakes is like looking for a needle in the proverbial haystack. Just ask Frank Masley of Boise, Idaho. He went looking for that needle and found an entire flag pole instead!

Frank has been an avid treasure hunter for fifteen years. Treasure, not gold. Coins, bullets, relics of any kind, not gold. But after years of the “same old thing,” he caved in and bought his first gold detector in May of 1997. Anxious to get right to it with his new Fisher Gold Bug-2, Frank and his good friend Bob Lyons made three trips in five days to break it in. The third time was a charm. On a 120-mile trip to the Blue Mountains just across the Oregon border, success waited for Frank.

Tiny gold nuggets and flakes are Frank’s targets of choice. And placer areas that were hand-worked a hundred years ago are his favorite destinations. According to Frank, old-time miners didn’t get all the gold. They were only interested in the big stuff and weren’t looking for tiny flakes. At $20 an ounce back then, it’s easy to see why they ignored it. Their recovery techniques were appropriate for their time, but not for ours. The holes in their screens were as big as ¼-inch, they didn’t use carpet on the bottom of their sluice boxes and they didn’t have metal detectors. “They left all the small stuff for today’s prospectors to find.”

And find he does; but to do the job right, Frank ground-balances his machine every few feet, especially within the highly-mineralized areas where he searches.

One day, while searching for gold with two friends, Frank got a couple of good signals from his metal detector, but thought he might be picking up hot rock. So he switched on his iron discrimination option to see if that would phase out the target, but he kept getting a signal. Then he dug the spot with a hand trowel to check it out further, but the beeping still continued. “One more shovel full, then another, then just one more,” he told himself. When he finally ran a handful of material by his search coil, Frank’s machine sounded-out a tremendously-loud scream. Frank now says it sounded like the whistle on a steam locomotive! So he thought he had found yet another lead bullet, since the area is littered with them. Then he began searching through the dirt in his hand. And there it was!

According to Frank, the gold nugget was so big, it could have jumped into his hand and told him all about it! “Oh my god, look at the size of that!” Frank yelled. “Bob, come here and look at this!” His partner meandered over and asked, “What are you hollering about now?” Frank popped it into his hand. “Oh my god! Look at the size of that!” Bob yelled excitedly. “That’s what I just said!” laughed Frank. The two were both jumping up and down like school kids and started to guess at its weight.

Frank said he didn’t realize it was as big as it was until he poured beer on it to wash it off. Neither of them had a quarter to compare its size to, or a dime or even a penny. But the nugget easily covered the only nickel they had between them. Its resemblance to a large kidney bean took them both by surprise as well; it was the perfect shape of a human heart. That’s also when he realized it had to have its own name, “Frank’s Heart of Gold.”

Frank has been a member of the Boise Basin Search & Recovery Club for ten years. In a short article recounting the event in a recent issue of their newsletter, he was referred to as Frank “Midas” Masley. It went on to report the statistics on his “Heart of Gold” nugget: 1.275 ounces, or 1.16 Troy ounces, or 23.25 Pennyweights, or 36.18 Grams.

Wow!

It’s not always easy to find the time to go metal detecting. But closer to home, Frank has still had the luck of the Irish on his side. One afternoon, he and Bob journeyed to the heart of a long-abandoned Chinese placer mining area in the Boise Basin near Idaho City. They had been there before and had uncovered their share of small nuggets. But after an arduous day of searching, they decided to leave; because the hour was late and the temperature was falling. As they turned to leave, Frank swept his detector over a spot he had already been over, and he got a signal that would “stop a bus.” Inside of one hole which was no bigger than half a cantaloupe, he uncovered a nugget patch and cleaned out a total of 203 small gold nuggets. What a find! After hitting pay-dirt so many times, perhaps beginner’s luck has nothing to do with Frank’s success. Maybe he has truly earned his nickname!

 

 

By David R. Toussaint

“Your metal detector doesn’t find the gold,” he told me. “You find the gold and then you put your metal detector over it.”

 

Metal detecting in the desertI met Don Gaines in late 1994, and he changed the way I think about gold hunting. Gaines, a retired Navy technical instructor, has found hundreds, maybe thousands, of gold nuggets by working the ore dumps from old gold mines with a metal detector.

“Huh?” I said. “Find the gold first, and then put your metal detector over it,” Don repeated patiently.

I wondered if this was just a variation of the old “gold-is-where-you-find-it” saying, or if it was really something new. As we talked, I began to see what he meant. To find gold, you have to know at least one of three things:
 
 
 
 
1) Where the gold is (if you know this, your success is guaranteed-duh!).

2) The rock formations associated with gold (a degree in geology helps).

3) Where gold has been found before (this only works sometimes).

 
Then a light bulb went on in my head. I already knew where the gold is and where it had been found before. I didn’t need a degree in geology to find it. Gaines had already found it in an ore dump near an old gold mine in southern Nevada. Why wander the desert hunting for placer deposits or pocket gold when I already knew where the gold was? This was no time to be timid!

“Do you think I can come out and hunt that ore dump with you some time?” I asked boldly. “Sure, it’s all right with me,” replied Gaines. “But you’ll have to get the permission of Harley, the mine owner. It’s his mine, on his private property. I’ve worked out a deal with him where he lets me keep half the gold that I find. Maybe you could work out the same kind of deal. Oh yeah, don’t forget to bring along a case of beer for Harley.”

GOLD!Four months later, I sat in Gaines’ four-wheel drive, looking across a sage-brush canyon at the mouth and head-frame of an old mine. Right there, next to a gravel road, was a sign that read, “PRIVET PROPERTY, KEEP OUT.” I didn’t know if the incorrect spelling was intentional or not, but it sure was effective. I had to wonder what kind of dangerous red neck could have written it.

There was a case of beer in the trunk. Across the shallow canyon, I could see two large ore dumps on the side of the mostly-barren hillside, both showing flattened-out spots where Gaines had been working them. About 200 feet to the left of the ore dumps was a house partly concealed by trees.

“That’s Harley’s house,” Gaines said, pointing across the canyon. “His father built it when he came out here around 1910. Harley’s father was in Goldfield for the strike there. He made some money and came here. See that big head-frame farther east?” Gaines asked, pointing at a brown dot on the hill about a mile away. “Harley’s father knew there was gold here because of that gold mine.” Sweeping his arm across the horizon, Gaines continued, “He filed a mining claim on this section next to it and hired an outfit to sink a shaft. About 100 feet down, they hit the vein that connected to that other mine.”

Metal detecting for gold in the desertSo, Harley’s father had known where the gold was, I thought; and that’s where he went to go find it. Of course, 90 years ago he did not have a metal detector to prospect with. Because of that, he missed many of the smaller nuggets. Most of the large rocks from the vein were crushed and the low-grade material was cast off in the ore dump.

Harley knew we were coming; Gaines had already called him from his cellular phone. This was probably a good thing. Later on, I asked Harley if he shoots at trespassers.

“No, I don’t shoot at them,” he said without a smile. “I shoot them.” “Oh, you mean you hit what you aim at?” I asked with a laugh. “That’s right,” Harley replied with a wry look. I decided not to press the matter any further.

Harley told me he had grown up in Chicago, just a few blocks from the spot where the notorious gangster John Dillinger was slain by the FBI. I found myself liking these independent desert dwellers. Harley gave me the same deal he had given to Don: He would allow me keep half the gold that I found. He would also keep the case of beer.

The next day dawned clear and bright with only a little wind. We were out on the ore dump early with pick, shovel and our metal detectors. I was using a new Gold Bug-2. I was curious to see how well the Iron-discrimination circuitry worked, how the 71-kHz operating frequency behaved and if the faint-target audio-boost could find smaller, deeper gold nuggets .

To get started, Don showed me his method of working the ore dump. On a flat area about 20-feet wide near the base of the dump, he threw out shovelfuls of the pale-yellow dump material. The dirt and rock seemed to leap from his shovel and spread itself evenly out about two inches deep over the flat area. “He’s done this before”, I thought to myself.

Wasting no time, Don picked up his detector and checked the larger rocks for gold. One gave him a signal, and he set it aside with some other large rocks. These he would crush later. Then he started tossing the other large rocks from the flat area; but instead of using his hands, he used his feet! The rocks started leaping from his lightweight running shoes like bullfrogs from a lily pad. Any soccer player would have been impressed. In no time, he had the flat area cleared of large rocks, and he began swinging his detector rapidly over the spread out dirt material.

“That’s a pretty fast swing,” I commented. “I get a sharper signal when I swing it fast,” Don replied. “You know, there is no right way to use a metal detector. The only right way is the way that works for you.” He soon knelt down, held the detector-stem in his left hand, grabbed a hand pick from his belt with his right and dug a small hole. Carefully making a small pile with the excavated dirt, he swept his detector coil over it. Hearing no signal, he rechecked the hole, and then ran a large cow magnet through it. The magnet protruded from the butt-end of his pick. After a few checks of the growing pile of dirt, Don must have located the target, because he grabbed a handful of dirt from the pile. Still holding the detector by the stem with his left hand, he started pouring small handfuls of dirt on top of the search coil with his right hand, jiggling the coil slightly to make the target sound off. After a few handfuls of dirt had fallen off the search coil, he heard the target and poked around in the dirt on top of his search coil with his index finger.

As soon as Don had the target in his hand, his hand flew away from the coil and a small piece of something flew away toward a large pile of rusty tin cans and other junk beyond the ore dump. I figured it hadn’t been a gold nugget. “It was a piece of blasting cap,” Don said. “It’s made of brass and it sounds just like gold.” “Can I see the next piece of blasting cap you find?” I asked. “So I know what it looks like.” “Sure,” replied Don. “These tiny pieces of blasting cap are all over. When the old- timers dynamited the vein, the blasting caps disintegrated and the pieces went everywhere.”

A few minutes later, Don found another piece of blasting cap and showed it to me, taking a short time out from the steady, unhurried pace he had set on the dump. It looked like a small, twisted piece of copper that had turned dark green from age. It joined the other junk in the junk pile. A few more pieces of junk; a rusty nail, a piece of tin can and a tiny piece of rusty wire emerged from the ore material and were quickly discarded.

Don spread another pile of the ore-dump material out on the flat area and let me search this one with the Gold Bug-2. After checking the large rocks, I swung the detector a few times over the dirt. In no time, it went “WHAM!” I flipped on the iron discrimination and it still went “WHAM!”

“Hot dog,” I thought, “This sounds like gold.” I pinpointed the target, knelt and started pouring dirt on the head of my search coil. “WHAM!” went the detector again. Gingerly, I poked around on the top of the coil until I moved the target. Certain I had a gold nugget, I poked a tiny piece of twisted dark metal and heard another “WHAM” in my headphones. I had found my first piece of brass blasting cap, the first of many I was to find.

“I usually find about 20 pieces of junk for every nugget I find,” Don said consolingly.

I kept swinging the search coil and digging junk targets until Don stopped me. “Hurry up,” he said. “Dig only the targets that sound good to you. To find gold you have to move material.”

Once again, I covered the flat area with more material, checked the big rocks and began swinging the detector. I soon heard another “WHAM” in the headphones. The signal sounded good, “probably just another piece of blasting cap,” I thought. I hunted the target down and found a rock about the size of your thumb from the last joint on. It felt a little heavy. I brushed off some of the brown dirt and saw a dull, yellow color gleam through. I was stunned. I didn’t know what to think. I couldn’t believe that I had finally found a gold nugget. What’s more, this was a good-sized one! “Don, look at this,” I said, tossing him the nugget. Don looked at it, rubbed it, spit on it, rubbed it some more and declared it a good find. “There you go,” he exclaimed. “Your first gold nugget. Let’s get a picture with you holding it.”

The nugget weighed about 2 grams, and it contained beautiful white bull-quartz, a really nice specimen. Later, we soaked it in a solution of hydrofluoric acid overnight; and in the morning, the quartz/gold nugget gleamed like a beautiful woman’s smile. I decided to make a pendant out of it for my wife Julie.

Although the first one was the largest, it wasn’t the last gold nugget I was to find during my week-long stay in southern Nevada. Dividing my time between the ore dump and the casinos, I was able to take about 20 grams of gold from the dump, of which Harley generously kept a little less than half. My take wasn’t enough to make me rich, or even pay for the trip, but it was enough to make me happy. Before I left the old mine, I buried a 12-pack of beer on the dump where I knew Don would be searching for gold. Later, he told me he got a good laugh when he found it, but I think he got a bigger laugh out of teasing me. He told me he had found a large gold nugget just below the 12-pack after he dug it out. Don doesn’t usually kid around too much, but this time I think he was fooling, or at least I hope he was.

Back on the job, as I sit at my desk, I often think about Don working the ore dump in the vast open spaces of southern Nevada. He once told me the first step to becoming a successful gold hunter is to retire, and I can see he’s right. The second step, of course, is to look where the gold is.

I now have an open invitation to return to southern Nevada and work the ore dump just about any time I want. Chances are I’ll return there someday. I’ve learned my lesson: Why waste time searching the desert in places the gold might be when I already know where it is?

 

BY DICK TURNER

A chronological account of the development of treasure and gold locators from 1830 to 1930.

 

As all gold hunters know, we are blessed with high-technology instruments to aid our searches for precious metals. Nuggets can be identified in a highly mineral matrix, thus eliminating unnecessary digging of unwanted material, and the Goldspear will locate even gold dust. However, none of these sophisticated detectors appeared overnight, nor was any one man responsible for the invention of metal detection.

THE PIONEER
If any one person could be regarded as the inventor of metal detectors, I will nominate English geologist and mining engineer R. W. Fox. It was Fox who first discovered that electricity will flow through metallic ores as well as solid metal objects. Thus, circa 1830 he devised a simple metal locator which consisted of nothing more than a battery, several metal rods and a suitable length of wire. His first method of detection was as follows: one metal rod would be driven into the earth where the suspected vein of ore was located; it was connected to one terminal of the battery. The other battery terminal was connected to a floating wire. Other metal rods were driven into the ground at several different points and successively touched with the floating wire. Where a spark occurred, it was an indication that metal was present. Circa 1870, this device was modified to two rods insulated from each other in a common probe and connected via battery to a bell and plunged into the earth. When contact was made by metallic ore, nugget or metal pipe, the bell rang, thus indicating the presence of a conductive object.

THE INDUCTION BALANCE

In 1879, Professor D.E. Hughes demonstrated to the Royal Society in London his Induction Balance (I.B.). Its purpose was to study the molecular structure of metals and alloys. However, Hughes and his instrument maker, William Groves, soon recognized the potential of the I.B. as a metal locator, and several were supplied to various London Hospitals for locating metal objects in human bodies. The Royal Mint used the Induction Balance for assaying metals and detecting forgeries.

The well- known American inventor George Hopkins modified the I.B. for locating metallic ores, treasure chests and the like. In fact, the Induction Balance forms the basis of most metal detectors we use today.

FURTHER DEVELOPMENTS

On June 21, 1902, the London Electric Ore Finding Company filed an application at the British Patent Office for an entirely new type of metal detector. This was a very advanced instrument for its time, having a range of one hundred yards. It operated as follows: a bank of batteries supplied a high-voltage, heavy-duty current to a spark generator; its output was chopped by a motorized contact breaker to achieve a signal at audio frequency, which in turn was fed to two transmitter probes driven into the earth. At a suitable distance away, two similar probes were connected to receiving apparatus, and equipotential lines of conducting material (ores or solid metal objects) could be plotted.

This company also developed an underwater spear-type detector which was used in locating gold bars in the wreck of the LAURENTIC, which was torpedoed during World War 1. This was a discriminating-type detector which could distinguish between gold and other metals. Unfortunately, the patent specifications are very brief and no illustrations are enclosed, hence we lack full information of how this detector worked.

Electric Metal Locating Company of Chicago took a different approach to metal detection, and based their instrument on the Wheatstone Bridge principle with two ground probes as sensors. A similar principle was employed by another American inventor Fred H. Brown who, in one of his patents, actually specifies his detector as being suitable for locating buried treasure.

THE WIRELESS AGE

With the very rapid development of wireless techniques during World War I, it was only natural that this technique would be adapted to metal locators and prospecting equipment. One of the first pioneers to exploit this technology for locating buried treasure was Englishman George Williams, who was the wireless operator aboard the salvage ship RACER during the recovery of gold from the wreck of the LAUREN TIC. Being fully conversant with wireless techniques, and seeing the somewhat primitive treasure locators available then, he decided he could improve the existing technology by designing a Radio-Locator (as metal detectors were known then).

In the book, “DIG FOR PIRATE TREASURE,” the author states that, “Williams had a metal detector of his own invention and used it to good advantage in Panama.” This surely must be the greatest understatement ever made relating to buried treasure. Further on, the author goes on to say that Williams “unearthed some wonderful stuff, including gold pots, candlesticks, silver bells and many historical things. A solid gold ball seven inches in diameter with a cross on top and gold leaves underneath.”

On January 7, 1928, The London Times newspaper reported that Williams found “a solid gold altar two feet high,” while C. B. Driscoll in DOUBLOONS expands the finds list even further. He also describes the Williams’ detector as a Transmit-Receive instrument operating at radio frequency. Williams, with his locator, arrived in Panama in July 1925, hence he certainly was one of the pioneers of T-R technique (see author’s note).

At approximately the same period of time, Radiore Company of Los Angeles developed a large-scale metal prospecting apparatus operating at fifty kilohertz.

Circa 1926, SCIENCE AND INVENTION magazine published construction articles under the title, “The Radio Gold Explorer.” So we see that even amateur gold hunters were catered to. By the mid-1930’s, there was an abundance of gold and treasure locators, the most notables being: the Alpha by George Maher, Terrasearch from Engineering Research Corporation, Radioscope by Goldak, Inc.; and, of course, Metalloscope from Gerhard Fisher. The Metalloscope was undoubtedly the most popular treasure finder of all time having survived in continuous production right up to the solid-state era, hence the M-scopes of the current Fisher line of detectors.

AUTHOR’S NOTE: In this article, I have attempted to give historical development of metal detection during the first 100 years of the use of electricity and electronics for this purpose, although other devices, mechanical (Dip Needle/Miners Compass) or physical (Pendulums/Divining Rods) were in use for several hundred years prior. As no reference books are available on this subject, I have relied on patents and articles published elsewhere to gain the necessary information. However; there are large gaps in my knowledge. For instance, the technical information and illustrations of the George Williams’ detector. I would be very pleased to hear from anybody who can supply further information. Please write to me direct at: 34 Nelson Gardens, London E2 7M, England.

Tags