Weekly journal-miner., 1918-03-20

! 8-foot by 3o-inch Hardinge pebble mills for Tegrinding. The discharge from the regrinding mills passes over two Wilfley tables; the table com centratcs go to the concentrates ele- vator, and the tailings and middlings to the same two elevators that re- ceivc the ball mill discharge. This puts the material that is too coarse for Notation in closed circuit with
 the regrinding mills and the conc classiher. The overflow from the cone goes to the Notation machine, a Minerals Separation standard type, of 600 tons capacity. Sufficient clear water is added to make a } to l
 pulp, three parts (by weighD of water to one of ore. The oil mixture rSed is } parts stove oil, petroleum prod uct, to I part refined wood creosote, Pensacola Tar and Turpentine Com pany's No. 200 oil and the total oil consumption is approximately lH pounds per ton of orc. Concentrate is taken off the first six or seven compartments of the machine and a middlings product of the remaining five or six compartments. For a while there were no middlings made but concentrates produced on all compartments, but 1t was found more beneficial to return a middlingS product to provide good proportion of shines in the Notation feed.
 At the boot of the concentrates elevator the table and Notation con ccntratcs flow together. From the head of the elevator they are led to Dorr Thickcner (40x10 fect). The ovrhow water from the Thickcner re- turns to the Concentrator Pond; the
 concentrates, thickcncd to a to 1
 pulp discharging to a Portland Con [ tinuous Vacuum Filter Q2x9 feeD. The filter handles satisfactorily the entire production of 100 to l25 tons of concentrates daily. delivering a cake with Is per cent moisture.
 The mill feed contains approxi- matcly 05 OF. gold and Is oz. silver per ton, and } per cent copper, N
 per cent insolublc, 13 per cent iron
 and 9 per cent sulphur. Table con- ccntratcs, which constitute 5 per cent of the concentrate tonnage run
 about IS oz. gold. Is oz. silver, , per cent copper. B per cent iron, Is
 per cent insolublc It is particularly
 to be noted that the table concen-
 tratc carries a high percentage of iron with its associated gold, whereas
 the copper and silver values arc the
 same as in the mill feed Flotation concentrates average 10 oz. gold. 40 oz. silver, 10 per cent copper, ? per cent insoluble, 25 per cent iron. Gen cral Mill Concentrates (miXturc Of the table and fotation ccnccntrateS) average .l2 oz. gold, 3.2 oz. silver, S.5 per cent copper, 20 per cent in soluble, 2S per cent iron, 3l per cent sulphur. Copper in tailings averages O.35 per cent go per cent of the gold and silver in the feed and 91 per cent of the copper arc recovered in con centrateS.
 From the hffltcr the concentrates drop to a l6-inch inclined conveyorI which carries them over two smelterI bins of $50 tous capacity each. Into these bins they arc discharged through a Jeffrey trippcr. One bin is cmpticd while the other is filling since it is necessary with such sticky material to keep man in the bin being drawn even though the slope IsI steep and the chutcs fitted with apron feeders.
 All direct smclting orc received intoI the plant both from the company'S mines and from outside mines is del livcrcd in railroad cars over the twelve receiving bins which have al combined capacity of 1000 tons. From these bins the orc IS discharged onto a short 50-inch convcyor belt that takes it to the 12x24-inch Blake breaker. The breaker crushes the orc to 4-inch and discharges 1t upon an inclined convcyor belt Q4-inch) | carrying it to the top of the Sample l Mill Building Here the orc stream is cut by a 6O-inch Nczin samples | taking a 10 per cent cut. The reject drops to a trommcl fitted with | punched plate screens QH-inch | opcning) Oversize from the trom- mel is conveyed 10 various blast fur mace bins for the different ores. Uu- dcrsizc from the trommcl falls to a set of 40xl5-inch rigid rolls which yield a product of about 54-inoh size which is conveyed by belt to storage bins for reverberatory feed.
 The sample cut s,by the 60-inch Nezin sampler gecS ito. a l0xz7inch Blake breaker. The discharge Is cut again by a Nozin sampler, taking 10 per cent cut, which is passco through set of sample rolls reduc- in- lt to about 1i-iueh size It then goes to a Snyder sampler, which takes 20 per cent cut giving the final