There were some who were curious whether the slotted riffles were capturing most of the gold (doing the work) in the Gold Well sluice. A picture is worth a thousand words.
For those curious then what the horizontal slots are there for, they are 'mixing wells' that allow the heavy and light material to separate more rapidly (notice chamfer on the leading edge of the slot not typical of a standard drop riffle), and to buffer material temporarily in case the operator overloads the sluice, so that material doesn't load up and wash out of the sluice before the gold is separated and captured.
Very little gold was collected in the slot riffles. Majority of the fine gold (not shown in the photo), was collected around 1/2 way down the sluice where the braking action of the slot riffles slowed the water velocity sufficiently. The chamfer leads the water down into the pocket where it creates turbulence and brakes the water velocity a small amount between slots, resulting in the same effect as a widening sluice.
Material was processed in Alaska.
For those curious then what the horizontal slots are there for, they are 'mixing wells' that allow the heavy and light material to separate more rapidly (notice chamfer on the leading edge of the slot not typical of a standard drop riffle), and to buffer material temporarily in case the operator overloads the sluice, so that material doesn't load up and wash out of the sluice before the gold is separated and captured.
Very little gold was collected in the slot riffles. Majority of the fine gold (not shown in the photo), was collected around 1/2 way down the sluice where the braking action of the slot riffles slowed the water velocity sufficiently. The chamfer leads the water down into the pocket where it creates turbulence and brakes the water velocity a small amount between slots, resulting in the same effect as a widening sluice.
Material was processed in Alaska.
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