Classify Your Material
As appearing in The Gold Nugget, January 2008
by Gary Hawley

At our November meeting we saw a video about black sand removal from concentrates. The information spoke of screening your material to -20 to make clean-up easier. That is, a screen that has 20 openings per square inch and anything that goes through the screen is classified as -20. I want to add a personal note to that information.

We have all sampled a new area by tossing a shovel full of bank material into a pan and washing it to determine if we want to spend more time in that location. This allows us to "wash off the rocks," moss, clay, and whatever else needs washing. No doubt this is a good idea . . . for the first pan. It will give you a visual of everything that was in the material and an indication of gold values in that area.

After that initial sample, it's time to get busy and move material quickly. The more dirt moved, the more gold recovered. With that in mind, I like to use the standard 1/4-inch screen (4 holes per square inch), the one that fits on top of a five-gallon bucket. Here is my procedure:

At this point, one can run the material through a sluice, wheel, or pan. Whatever method you choose, you are running 1/4-inch material. I have decided that I am going to classify my material at least one more time, to -20, before running it. Here's why:

My plan is this:

I should save time and effort because I will be runing similar-sized material, less of it, and it should be richer.

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