gold placer deposits – Earth Science Australia. The geology and methods of mining gold placer type deposits.… breaking through floors in old building ruins, and falls or cave-ins in old mine workings. ….. The screen or bars (a "grizzly") should be sloped so the oversize material rolls off to …»More detailed
"The Grizzly Gold Trap runs at less of an angle and less depth thanks to the built-in slope in the design. The part that sold it to me though was the grizzlies. They were at a smooth angle and as such there was a lot less rock build ups.