[D0014AAI], Letter from Cloyd Mason Chapman, John Vincent Miller to Thomas Alva Edison, June 19th, 1900


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[D0014AAI], Letter from Cloyd Mason Chapman, John Vincent Miller to Thomas Alva Edison, June 19th, 1900





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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University


Dolores, N. M.
June 19, 1900
Mr. T. A. Edison,
Orange, N. J,
Dear Mr. Edison :-
We have completed the experiments relative rates of food and proportion of coarse and fine and have determined on 50 to 60 per-cent of coarse, running at the rate of two tons per screen per hour, which is double the rate we had at the laboratory. We are at present making two series of runs _ passing the material over the fine screens first, .007 and up, and over the large screens first, .119 and down. We shall take four sizes from each run and pass through the separator and make an accurate determination of the efficiency of both methods. From present indications the method of using the coarse screens first seems to be better because all material breaking up in the screening methods and comes out with its proper size _ and thus we prevent the accumulations of fines in the larger sizes.
We have been using a quarter inch square screen for getting out mill size. The material between this and our largest screen in the mill, .119, amounting to about 500 lbs. we have panned but found no pieces of gold of that size, which leads us to think that perhaps there will be no need of such coarse screens and that the gold is all under this size.
We hold back the map of the mesa in order to make some additions, as the extension of the arroyos and the location of some of the old shafts. This work has been completed and as soon as Mr. Burn makes a tracing and blue print we shall send it on. A few days we made a rough determination of the amount of water in the Galisteo River and found it to be 350 to 375 gallons per minute. To put in a weir to accurately measure the water would necessitate considerable work and expense owing to the fact that the dam would have to be built very substantially to withstand the frequent freshets. We should like to know whether you wish us to go to much expense in the matter.
Yours truly,
Cloyd M. Chapman.
John V. Miller
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