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Ch. 18: loss Gold Quicksilver

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LOSS OF GOLD AND QUICKSILVER.
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are estimated to lose from 7 to 8 pounds of quicksilver per run of 10 weeks.
Delaney and New Kelley Claims.—The annexed table shows a run at the Delaney and New Kelley claims, in Stanislaus County, where the grades are light; the de­tails give the amount of quicksilver charged, less of quicksilver, quantity of water used, and the cubic yards of gravel mined, with all attendant costs.
There was more water used in the Delaney than in the Kelley, and the sluices of the former are much shorter than those of the latter. The composition of the amal­gam obtained at the Delaney was as follows:
One hundred and fifty-eight pounds of this amalgam were retorted, from which 90 pounds of quicksilver were distilled, showing a loss of 12.62 per cent. The retorted gold weighed 55 pounds, and, after melting, 52 pounds— a decrease in the weight (from slagging off impurities, lead, etc.) of three pounds, or 5.76 per cent. The fineness of this bullion was .895.
Loss of Gold.—The most efficient means of saving gold from cement gravel are a liberal use of the best shat­tering powder, breaking the cement before it is washed, and the introduction of several " drops," when possible, along the line of the sluices. Frequent drops and short lines give better results than a long, continuous line.
Gravel moving in sluices is subjected to a grinding and scouring process which alone is not sufficient to dis­integrate the cement gravel unless the sluices are of great length. The lessening of grades and the use of undercur­rents tend to diminish the loss of fine gold. Extensive lines of sluices and undercurrents are expensive to build and keep in repair. Like the last concentrator, the last undercurrent will always catch some metal.
Ch. 18: loss Gold Quicksilver Page of 331 Ch. 18: loss Gold Quicksilver
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