Every prospector wonders what percentage of gold is captured in their sluice and how much escapes downstream. There are many factors that affects this — sluice type and setup, stream velocity, feed rate, material size, and on and on. We've set out to run tests to provide some insight into how much gold the Grizzly Gold Trap captures. We will continue these tests and reports and will be running them with prospectors around the Denver area on a variety of rivers.
We set up an Explorer sluice in a stream with decent flow, enough to clear 2-3 inch rocks over the grizzlies. The setup angle was approximately six degrees. Directly below the Explorer we set a Gold Hog stream sluice to capture all the material that went over the grizzlies and the material exchanging out of the capture chamber. The material we shoveled onto the Explorer’s transport deck included gravels and rocks up to 2-3 inches in size. This test run was about one hour of pretty constant feeding of material into the sluice. We were conscience of our material feed-rate, but as always, there were some times when a large shovel full of material dumped onto the deck and overloaded the sluice — happens to all of us.
After getting the cons out of each sluice, the amount gold we could see in the cons from the Explorer looked good (image below), and as expected, there was gold in the cons from the Gold Hog.
In our final cleanup, we processed both sets of cons with finishing pans, and then ran the remaining black sands through the miller table to see if we missed anything.
The Explorer caught approximately 90% of the gold we ran that day, which was an exciting number. If we adjust this number assuming that the Gold Hog also captured around 90% of the gold the Explorer lost (10%), then the percentage of gold caught by the Explorer Gold Trap would drop to around 89% captured. One interesting aspect in this test was that there was a significant amount of finer gold caught in the Explorer than what was in the Gold Hog mats. The gold captured that day ranged from a few +20 flakes down to finer gold around -150 in size.
Gold captured in Explorer Gold Trap
Gold captured in Gold Hog
Taking a close look at the gold that escaped the Explorer Gold Trap, there is one really interesting larger flake that is shaped almost like a helix, which may explain why it was not captured.
Closeup of 'helix' shaped flake in Gold Hog
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Our final adjustments to thermoforming molds were a success and we are now into production runs, assembling sluices, and will begin shipping units out Friday afternoon...