BY DAVE McCRACKEN
THE BASICS OF SUCCESSFUL GOLD MINING
Part Three - Sampling is a never-ending process
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You would think that sampling could end once you've
found a pay-streak. Because once you've found a pay-streak, you start
your production operation to recover the gold. However, sampling
continues on, possibly even to a greater degree, after you've located a
rich deposit.
When you locate a deposit that you have determined is good enough to
work, your next step is to define your deposit's boundaries. This takes
more sampling. It is generally done by dredging or digging more sample
holes. The first and most important boundary you should find, especially
if you are dredging, is the lower end, meaning the downstream end of the
pay-streak. This is because you need to find a place to drop your
tailings where they won't wash onto part of your gold deposit.
In mining activities of any kind, tailings placement is of primary
concern right from the beginning of the operation. You generally don't
worry about it too much during sampling, because you have not determined
there is a deposit in the immediate location as yet. But as soon as you
are certain there is a deposit worth developing, where you place your
tailings becomes very important!
In dredging, providing you are going to have the time to develop the
entire deposit, you generally back your dredge further down river,
dredging sample holes as you go, to locate where the deposit plays out.
It is then smart to dredge a few more sample holes below this point to
make sure the deposit really did play out where you will put your
tailings. Then, start dredging from the tail end of the deposit, and as
you move forward, drop your tailings on the area that you have already
worked.
As you work the deposit forward, you also must locate the left and right
boundaries of the deposit. This too requires your sampling attention,
only in a different way. Rather than dredge or dig sample holes, pay
close attention to how much gold you are recovering while continuing to
move your production hole in the direction of each side of the deposit.
In dredging, if you are into a healthy deposit, you will see gold when
you uncover that strata of streambed material where it is located.

As I mentioned in the earlier parts of this series, when you find gold
in a sample hole, the first thing to do is figure out where it is coming
from. Is it from the various streambed layers or off the bedrock? This
also applies to production mining. You need to know where the gold is
coming from so you can watch that strata of streambed material to make
sure it is still paying as you move your production hole forward and
toward the left and right side boundaries of the deposit. In dredging,
if it is a good pay-streak, when the proper pay strata is uncovered, you
can actually see the gold if you slow down and look. You will also see
much less or no gold once you extend beyond the boundaries of your
pay-streak. It is standard practice to slow down and watch your pay
strata closely when production dredging. By following this procedure,
you'll continue to dredge up pay-dirt with a minimum of non-paying
material. So, you can see that the job of sampling never really ends,
even when you're in a good pay-streak--especially when in a good
pay-streak!
When digging, as in high banking, you cannot depend on seeing your gold
as you dig in the pay strata, so it can be necessary to clean-up your
recovery system more frequently to make sure you are still mining in a
section of the gold deposit. You can also sample the pay strata with a
gold pan on a regular basis to make sure it is still paying in
sufficient quantities.
The idea behind a production operation is to mine all of the deposit,
while mining as little of the non-paying material outside the deposit as
possible. However, you cannot always directly see where the deposit
plays out. You must be constantly watching how well the deposit is
paying and where it seems to slow down. This can sometimes be difficult
to do, because some pay-streaks are not entirely consistent. A
non-visible obstruction or change in the bedrock upstream can cause an
entire section of pay-streak deposit to blowout, giving you the false
impression of a boundary--when there might be an even richer section of
the pay-streak several feet beyond where it apparently plays out!
Keeping these thoughts in mind, just do your best to figure out what the
deposit is doing as you follow it. And, you need to devote some time and
energy continuing to sample beyond the apparent boundaries of the
pay-streak every once in a while to make sure you are not missing
anything important.
Short of actually finding a rich pay-streak, finding an increase in the
amount of gold in a sample hole is the best sign to look for while
testing. Finding an increase in gold means more sampling is a good idea
in the immediate area.
In the same way, finding a rich pay-streak means much more sampling is
justified in that immediate area--especially beyond the apparent
boundaries of the pay-streak you are working. This sampling is best done
as you move forward, before you start dumping your tailings in that
location.
Another important thing is to determine for yourself how much gold you
actually need to recover on a daily basis to make it worth your while to
work the deposit. Sometimes there is a big difference between what a
person says he or she must recover and what a person will accept in
order to stay in a deposit. You should be honest with yourself about
this. If you need to recover five pennyweight a day, then you should not
be production mining in gravel which is paying only one pennyweight a
day, unless you have some reason to believe it is going to improve right
away. Also, if five pennyweight a day is your acceptable level, you
should mine the lower-grade gravel on the boundary edge of a pay-streak
if it is paying this much or more, no matter what the higher-grade
section of the gold deposit is paying.
Some pay-streaks have a richer portion in the center or along one edge,
and a lower-grade section throughout the remainder, which still may be
high-grade enough to work by your own standards. Yet, you will find
yourself much more interested in recovering the gold out of the rich
section, because it is more exciting as you uncover all that gold. It
takes personal discipline to work all of the acceptable portions of the
pay-streak, when only one portion is extremely high-grade. I have seen
many deposits (some of them my own) wasted by miners moving forward,
dredging only the high-grade, while dumping tailings on the lower
grade--but still acceptable--portions of the pay-streak. We all learn
through hard-won experience just how valuable pay-streaks are once they
are located, and how important it is to production-mine them in a
disciplined orderly manner, wasting as little as possible.

There is an old maxim which always seems to be true: If you are looking
for easy gold, go where others have already found it, and look beneath
the area in which they started laying down their tailings! People get so
excited when first discovering a deposit, they generally don't think
much about what they are dumping their tailings on top of until it is
far too late!
So, sampling really never ends. When you are not in a deposit, you will
find yourself sampling to find one. When you find one, if you are wise,
you will constantly sample to keep yourself within the boundaries of the
deposit. Then, you'll need to sample again to find another pay-streak in
the immediate area once the first one runs out. Sampling basically is
your procedure to acquire the necessary knowledge of where the gold is
so you can recover as much as possible for your efforts. This is why you
want to be good at it. Don't quit!
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