Mohave County miner., 1918-03-16
(By P. R. AIilnes)

(by r. h. AlllneS)
 PRESCOTT, March 14.-The' Con- solidated Arizont Smelling company's plant at Humboldt, Arizona, is treat ing 500 tons of ore daily and produc- ing therefrom about 1,800,0O0 lbs of copper per month. Approximately half of the copper production is from the ores of the company's mines, the Bluebell and the De Soto, and the balance from custom material.
 The ore deposits of the two com pany mines are of the same type, re- placements in schist by chalcOpyrite and pyrite accompanied by secondary silififications. In physical character istics the ore bodies are rather chim- neys than lenses; in the Bluebell mine six ore bodies are being worked and in the De Soto also six, which have persisted with practically the same di- mensions on each level from the sur face to the deepest workings-1200 feet in the Bluebell and 800 feet in the De Soto.
 The Bluebell ore bodies vary in length from 100 to 400 feet and in width from 5 to 25 5feet. Two sys- tens of mining are in use, "cut and fill" and overland stoping on ore or "shrinkage stoping," the latter method predominating and the former being employed only where the stope walls are bad, due to severe faulting. The ore is hosited to the surface in sldps through a three compartment shaft and dumped into bins from which it is drawn for the buckets of the aerial tramway to be carried three miles to the railroad. There it is loaded in 4O- ton cars for the Emile haul to Hum boldt over the Crown King branch of the Santa Fe system. The Bluebell mine's present production is 10000 tons of ore per month and the mining cost, including development, is $2.75 to S3 per ton f. o. b. cars Bluebell siding.
 The De Soto mine is worked through a 2OOO-foot adit which corresponds to the 6OO-foot level of the mine. Five levels have been opened above the adit and two below it, and the mines s production of 15O tons per day is hauled by mules from ore pockets on the adit level to the bins at the upper terminal of the aerial tram, dis tance of 23O0 feet. The tram line is 4OOO feet long and operates by gray | ity, there being a difference in eleva- tion of 1000 feet between the two ter minals. In addition to overcoming friction and pulling up the empty buckets, considerable energy is ab- sorbed by brakes. This energy will shortly be utilized as electric power 1 by gearing a motor to the bull wheel, which motor may be reversed and op- erated as a generator delivering as electric energy the surplus power which serves now only to heat the friction brakes.
 At Humboldt are the concentrating mill and smelting plant. The concen- trator, capacity 500 tons per day, treats exclusively the more silicious ore from the Bluebell and Dd Soto mines.
 From the crushed ore bin the ore, which has been reduced to 1-2 inch, is drawn as required for the ball mills by two apron feeders discharging onto 20 inch conveyor belt. This belt runs over Merrick weightometer with au- tomatic register recording the tonnage passed over it.
 The mill feed contains approximate ly .05 !oz. gold and Is oz. silver per ton, and per cent copper, 57 per cent insoluble, 13 per cent iron and per cent sulphur.
 From the filter the concentrates drop to a 16-inch inclined conveyor which carries them over two shelter storage bins of $50 tons capacity each. One bin is emptied while the other is filled, since it is necessary with such