Bisbee daily review., 1920-05-18

l llYered in cars for shipment to the ] shelter at Douglas, will be as fol
 lows:
 The ore will be hauled in ten car l trains over the company railroad, a 1 distance of two miles to the mill | Here it will be dumped, one car at a time, into the large jaw crusher pro
 vided for the primary crushing. This
 crusher has jaw opening of feet i by : feet and will take a rock of that
 size. The total weight of the crush CT is three hundred sixty tons; the l largest piece of the machine weighs | forty tons. It has a capacity of one carload every two minutes, and will reduce the ore to S-inch pieces From | the primary crusher, the ore will be conveyed to two No. 9 gyratory crush CTS, where it will be further reduced to inch pieces. From the gyrator- ies it will be conveyed to Symonds vertical disc crushers which will re- duce it to IA inch pieces From these crushers it will then be con- veyed to storage bins at the head of the mill, passing over an automatic weighing machine enroute to the bins.
 From the storage bins at the head of the mill. it will be conveyed to each unit by belt conveyor and de- livered to the Rod mills for further grinding As the ore enters the Rod mills, water is introduced, and from this point on all further reduction in size is done by wet grinding. The product from the Rod mills will be run over roughing tables, and approx imately 40 percent of the copper con tained will be recovered in the gray itv concentrates from these tables. The middlings from these tables will be reground in the Rod mills. and will go to the flotation machines, which are of the Callow pneumatic type, where about 45 per cent of the total copper content will be recov- cred in the flotation concentrate. The tailings from the Notation machine will be given a finat treatment on finishing tables which will make a further extraction of approximately 3 Der cent Of the total copper con tent.
 The gravity concerI rates will flow into tanks located at the foot of the mill where the excess water will be removed before shipment. The flota- tion concentrates will flow by gravity to tanks provided for them at the foot of the mill, from whence they will be dewatered before shipment by means of Oliver filters. The tailings from the flotation machines and the tables will flow to a large concrete tank provided for them at the foot of the mill where the water is re- moved to be used again. while the tailines are conveyed through an op- ening in the bottom of the tank bv means of proper Iaunders, to the tail ing dump located on the hill side be low the mill.
 The ratio of concentration will be about four tons of ore into one ton of concentrates, and the average grade of the concentrate will be be tween and s percent copepr.
 Water for the mill will be pumped from the C. & C. shaft of the com pany located on the hill side above Warren. With the mill running at full capacity, the new water required will average about one and one-half million gallons per day. A 6OOfoot tunnel has been driven through the hill between the C. x c. shaft and the concentrator, through which the water will be conducted to concrete reservoir at the head of the mill.
 Power for the concentrator will be generated by waste 'heat from the smelter at Douglas and transmitted 10 Bisbee over the power line which was erected last year. A subsidiary power plant, however, for emergency use is being erected near the mill site. h. stalled in this emergency plant will be four Diesel engines, two Of 1000 horsepower. and two of 2000 horse power, which, will supply power for the mine and the mill in case of ln- Corruption to the transmission line.
 As the ore will be handled automat- ically throughout from the time 1t is loaded into cars by steam shovels, the number of men required to operate the crushing plant and the concentrator is estimated at about sixty, Of which only about one-third will be employed in the actual operation of the crushing plant and the mill, the remainder be- ing mechanics and repair men.
 There will be three classes of ore mined by the steam shovel. The very low grade ore assaying from 5-10 to per cent copper, of which there will be approximately 100000 tons, which will not pay the expense of milling, will be placed in pile by itsef on  site scected near Don Luis, and an at tempt will be made to recover the cop per values from same by teaching. Ore assaying from 1 per cent to 31A per cent copper. of which there will be approximately 16,500,000 tons. will be concentrated. Ore assaying above 3 1@ per cent copper, of which there will be approximately 1,500,000 tons, will be crushed at the mill and delivered into bins at the foot of the hill for ship ment direct to Douglas.
 Although the Copper Queen coucer. trator win not be the largest in the state, it will no doubt show a conaid- erable improvement as to equipment and efficiency.
 J. E. LanninS is the chief draftsman in charge of the engineering office. anu Harry Bible is superintendent of construction.