Yes. Yes. Yes. Thanks very much. I will take a Drott 25 and a D6 for the small power equipment and a 100 foot Ross Box to sluice.
Real men don't need dynamite for mining hardrock gold. They can use a pickaxe and some elbow grease.
In 1920's there were riots in South Africa when they introduced the hand crank leyner air drill to the stopes. The men wanted to stay with double jacking hand steel. They knew automation led to layoffs.
Speaking of placers, let me tell you about a small mine they had in a tiny valley in California about 1850 or so. It was called the Ross Placer. It was a valley that had Gabbro intrusives that were cross cut with gold veins. The veins themselves were uneconomic, but the placer was a good low grade prospect. At the head of the valley they had some monitors setup to cut the clay banks about 1/4 mile away. They diverted a river some 30 miles to the site in a dug trench and fed the stream to the monitors. The pressure from a monitor which was also called a giant, (an auto-pointing nozzle), would kill a horse if the water stream hit it from 1/4 mile in distance. Several streams combined to be fed to the main sluice, a cut in the ground 1 mile long, 20 feet wide, with water 12 feet deep, coursing at 25 miles per hour. 75% of the values would be found in this sluice at clean up in the first 1500 feet, with the rest spread decreasingly over the next mile. The riffles were 4 inch posts about one foot or more high, or boulders layed in rows in the bed.
At one place in the valley they needed to suction the material from the bed and move it over a cliff. They used what is called an airlift pump. They diverted a stream through a pipe down the cliff and turned it back up into another necked down pipe 3 feet in diameter. The turned flow would lift boulders one foot in diameter back up the cliff 100 feet.
The grade of the Ross, which was quite profitable, was 15 cents per yard. I believe gold was 16 dollars per ounce then, so the grade was .009 ounces per yard.
In one valley in California there was 5000 miles of wooden staved pipe some 3 feet in diameter.
It all ended in 1920 in one court decision when a judge ruled that placer mining companies were responsible to downstream landholders for the damage that the bank overflows caused that placer mining seemed to be causing by his hydraulicing upstream. In fact it was the sediment load downstream that caused the river to meander and not the just the volume of flow as modern geomorphologists now know. The River's energy increases with its sediment load and it selects new pathways because it has higher mass energy (momentum) and there for pushes harder on water ahead that has no egress or outflow momentum. Ergo, the length has to increase - meander.
In the really high grade Yukon in 1895 (some mines ran a half ounce per yard or better in the pay levels) most men made money with a rocker that could handle 4 yards a day with two men. One rocked a sluice-cradle and dipped water, and the other one shoveled. First, of course they had to mine down 30 feet and get the river bed bottom gravel and get it to surface.
There may still be some 500 or more operations in the Yukon (don't know if they are still there.) Most use caterpillars and real power equipment. In the late 80's the best placer in the Yukon produced 12 thousand dollars from 1000 yards of gravel processed per day. This operation had a D6, a one yard hoe, and some 12 men working the sluice, which looked to be about 250 feet long.
The country with the longest history of placer mining is China, where it is known that operations have gone on for the past 4000 years. The conical wooden hat of the Chinese peasant double as a Batea or conical wooden gold pan. When you see Chinese in illustrations dipping their hats for water in a river, don't bet that they are not checking out the values in the bed. Every placer area in North America from the Carolinas to Michigan to James Bay had Chinese working, and they were always the last to leave. It may be that the American Dreadnoughts were built with California gold, as was Studebaker and GM, but I will wager that a fair number of restaurants and laundromats owe their origin to river gold as well.
Find me a mine where we can make money with a pan, (one yard per day) or even a small Knelson and I leave tomorrow.
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