Excavator Testing Wet Placer Ground
April 2013 by Jim HalloranThe excavator or backhoe has become the tool of choice for testing placer ground. These machines are the best way to explore and sample a placer deposit if the ground is not too wet or frozen and bedrock is not beyond the reach of the machine.
After your excitement peaks when you first receive the high gold assay from the vein you just exposed, you ponder how you will extract and sell your gold. You will need to develop a flow sheet for your process to optimize your recovery and minimize your costs and permit requirements.
Before I tell you what dredging backwards is, I’ll tell you why my team and I decided to give this very unconventional dredging method a try.
Our destination was some old hydraulic workings where the old miners had washed literally mountains of material away to expose gold in ancient river channels.
Some media outlets have speculated the hoard of coins came from a theft at the old US Mint in San Francisco that was reported in 1901.
When it was all setup and running, you had everything coming off the dredge riffles into the boil box. At the hole section, some of the water got sucked down and pulled a lot of black sand and over heavies…
So, how much rain does it take to cause a major movement of gravels in a stream and redistribute the gold? The technical answer is enough water to move the bed load of the river.
I like to think in terms of “conductive mass” because it is a combination of both the conductivity of the metal and the size of the target that determine how a detector sees conductivity.
The Bawl Mill • Ask the Experts - processing plants that can extract rare earth metals • Ask the Experts - what does MDB&M stand for? • Ask the Experts - proper mining claim procedures • The Hughes Creek Placers, Montana • Benefits of a Detecting Partner • Hard Rock Milling: A Matter of Scale • Paperwork Guy—A Cautionary Tale • ICMJ Online Forum Now Available • Detecting For Gold—Are You Up For It? • A Trip Down the Yukon River • Selenium, Mercury and Suction Dredging—Studies Contradict CA State Water Resources Board • Melman on Gold & Silver • Mining Stock Quotes and Mineral & Metal Prices