Proper Assaying of Placer Samples
November 2012 by Jim HalloranThe whole purpose of sampling mineralized ground is to measure the values in a small volume of material that would be representative of a much larger volume of similar material. The key word is representative. Chemical and fire assaying will not accurately represent placer deposits by themselves.
I will make the assumption that when any of you take a detector in your hand and head out prospecting for gold you are probably anticipating finding some gold. That’s the general idea, right?
On my weekends off I spent many hours dredging the Second Broad River from Cane Creek Road up to the headwaters. I used a three-inch dredge with air and graduated to a five-inch with air.
After removing about six inches of dirt and cobbles, the sound was a bit more recognizable. I was now confident that there was a definite target and not just a ground noise.
Some claim they can smell gold. This may be, but when I take a whiff of gold, I smell dirt, rotten eggs, garlic or just nothing: my nose is everything but sensitive.
Most prospectors understand placer mining a lot better than hard rock mining and don’t realize the amount of work that goes into processing different types of hard rock ore.
My first clean-up showed that my efforts were not in vain. There was considerable color with some good-sized nuggets in the riffle trap.
I am going to suggest dozens of ways you can increase suction power, dredge to greater depths, and improve recovery methods in your sluice box.
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