Made by Arthur Barr, this short film shows some of the technologies used by prospectors to find gold in the 1849 California Gold Rush. At 2:00, a prospector shows how a pan is used to sift river sand in search of gold flakes. At 2;24 a claim is staked out with a claim post. At 3:30 a rocker or cradle is made to sift gravel. At 3:53, wooden bars called riffers and a hopper to hold the sand and gravel are created from wood. At 4:40 the operation of the hopper is shown. At 6:17 a Long Tom sluice is shown, which used the power of the river to separate the sand and gold from the gravel, with gold trapped behind the riffle bars. At 8:00 gold flecks are recovered from the Long Tom via a pan. At 8:30, a series of riffle boxes are placed together to form a sluice box -- the best of all placer mining tools.
Placer mining is the mining of stream bed (alluvial) deposits for minerals. This may be done by open-pit (also called open-cast mining) or by various surface excavating equipment or tunnelling equipment.
Placer mining is frequently used for precious metal deposits (particularly gold) and gemstones, both of which are often found in alluvial deposits—deposits of sand and gravel in modern or ancient stream beds, or occasionally glacial deposits. The metal or gemstones, having been moved by stream flow from an original source such as a vein, are typically only a minuscule portion of the total deposit. Since gems and heavy metals like gold are considerably more dense than sand, they tend to accumulate at the base of placer deposits.
It is important to note that placer deposits can be as young as a few years old, such as the Canadian Queen Charlotte beach gold placer deposits, or billions of years old like the Elliott Lake uranium paleoplacer within the Huronian Supergroup in Canada.
The containing material in an alluvial placer mine may be too loose to safely mine by tunnelling, though it is possible where the ground is permanently frozen. Where water under pressure is available, it may be used to mine, move, and separate the precious material from the deposit, a method known as hydraulic mining, hydraulic sluicing or hydraulicking.
My brother has gold fever so bad he has bought into claims across several states. Of course that means travel. Just in the last week, he's panned in ID, CA, GA, SC.
ReplyDeleteHe's the one who panned over one ounce of AU over two days out of the Feather River. That was in the 1980s. Tourmaline and opal are also his interest. In the recent two years, he's now into turquoise. But AU is his first love.
In the three months I was in Calaveras County to help build a house, there were several interesting events and each associated with gold.
ReplyDeleteFrank, a part time resident, drove a few of us along the PG&E access roads. On a road along a river, we were shot at. A delapidated trailer across the river seemed to be the place where the shots came from. Frank explained these were folks thinking we might be jumping, or at least scouting, their claim.
A couple of days later it was rather hush hush that a couple of bullet riddled bodies came floating down. Sheriff had no comment, not even to say there was an investigation.
Then a 6.2 lbs nugget was found. A few weeks later a 3 lbs clod, mostly AU filigree in quartz was found in the area. Cleaned up it was beautiful and sold for millions.
Another body was fought, shot up with bullets. This on a different creek.
Lastly, at a BBQ hosted by a local, I made comment that I bet that there stream at the end of his yard holds gold. Them around went suddenly silent. The host looked me square in the eye and said that after I'm finished over at Frank's he better never see me around there again. No, he wasn't playing a joke on me.
That all happened in three months time in one area. Those folks are serious.
The law in ID says ya gotta fill in yer diggings when yer done. I told my brother that he should place felt or a screen at the bottom when he fills in the holes in the stream bed (to be dug up later). But he didn't answer. I wonder if the law forbids that too.
ReplyDelete