Thompson and West
History of Placer County page 223
The Independence Hill Mine, as described by Mr. Hobson lies on the extreme west end of Roach Hill ridge, and tails into the North Fork of the American River through the Independence Hill, Union, and Blue Wing Canyons. The mine is rigged up to work on a large scale, using 500 inches of water. The rig consists of 2,000 feet of 16-inch iron pipe, one No. 4 giant nozzle 800 feet of 40 inch flume with improved iron riffles, two large under-currents, also paved with iron riffles, mining tools, and tools for making iron pipe, blacksmith shop, melting room and assay office, powder-magazine, etc.
This mine contains about fifty acres of ground, twenty-five of which have been washed off. Nine acres of this amount was washed off in a small way, during a period of sixteen years; and since rigged to wash on a large scale, sixteen acres was washed off in 256 days, working twenty-four hours a day, using 500 inches of water under a pressure of 350 feet. Under this work, the following are the results, as obtained from the books of the Superintendent—
Total number of working days, using 500 inches of water twenty-four hours, 256. Ground washed off sixteen acres, eight acres averaging in depth, thirty feet; eight acres averaging in depth, seventy-five feet.
Total amount of gold produced $62,003.20
Total expense of mining 29,078.82
Total net profit from sixteen acres 32,924.38
An average gross yield per acre 3,878.19
Gross Yield per day 242.20
Expenses of mining:
Five hundred inches of water (24 hours) 45.00
Ten miners at $2.50 and $3.00 per day 27.00
Fuel and lights 5.00
Powder and incidental supplies 31.60
Superintendent 5.00
Daily expenses 113.60
Leaving a net profit of $128. 60 for each day