Milling Practice At Morning Mill

THE problem at the Morning mill is to separate the galena, which contains a great percentage of the silver, from the sphalerite, making each into a commercial product. The ore as received from the nine is dumped into hopper-bottomed bins of 1200 tons capacity. These are divided into five sections, the first section being the regularly used section and the re-mainder used as a reserve bin. The ore is first passed through a 9 by 15-in. Blake jaw-crusher with an opening of 4 in. This allows a ham-mer head to pass through without damage. The crusher discharges to a conveyor that delivers the ore into a two-section punched-plate trommel screen with 1 ½ and 2-in. openings. The undersize is carried by means of conveyors to the mill bins. The oversize passes over a shaking feeder and through a spray or high-pressure water to a picking-belt, where waste and crude ore is hand-sorted. About 4 per cent of the ore by weight is picked out as waste, assaying about 0.6 per cent lead, and this is discarded over the dump. About 4 per cent of the ore by weight is removed as crude ore, assaying 10 oz. silver, 30 per cent lead, and S per cent zinc, and is shipped direct to the smelter. The remainder of the oversize from the picking-belt is con-veyed to a 4-ft. Symons cone crusher with 1-in. opening, which is interesting as a new introduction in this dis-trict. The machine consumes approximately 40 hp. and the pinion shaft travels 555 r.p.m. The horsepower is rather high, but the machine has an extraordinarily large capacity, and, due to the unique construction, there is no danger of tramp steel causing any damage, as in that case the discharge "opening" is automatically