Arizona republican., 1915-09-26

tlie LOOT as II Just Drohen. small drill is ready to commence on raise.
 Next comes model of the system of mining in vogue at the renowned
 Homestake, in South Dakota, one of the worlds greatest gold mines It has paid $35,000.OO0 in dividends, and yet there is 20 years ore develop ed. At present the mills are crush ing 4500 tons of S4 ore daily. This carefully made model, if correctly un- derstood, conveys as much informa- tion as a good-sized volume on min ing methods. It illustrates the work ing of a wide vein of low grade ore by shrinkage- -stoping. By a com plexity of drifts and cross-cuts the 500-ft. wide zone of schist and quartz is divided into blocks 800 fit wide, 60 it. long and 150 1t. high. This block is shot down in pieces up to 50 tons in weight for a height of 115 ft., and allowed to remain where it falls, without the use of timber. The 35 it. separating this stope from the ground above is worked by means of square-sets and then the whole stope is filled with waste. A mat of heavy timbers supports this waste and allows it to settle gradually. This is an admirable model and should be secured by one of our uni versailles. Sample of ore and rock from the HGmestake are also on view.
 Among the photographs on the wall, those that show the wreck of the Wardner mill after it was dynamited on April 29, 1899, by a thousand or more miners who came on a captured railway train, and the photograph of the ili-famed bull pen" in which sev eral hundred miners were subsequent ly imprisoned, should be of special in terest to students of our industrial history. A Baldwin Westinghouse storage battery (Edison) locomotive, hauling two 25-ton cars of ore just filled from chute, is ready to pass out of the level. On the lower levels storage batteries are used; trolleys appear in the main adit.
 Copper men have their turn next at the Copper Queen mine. Arizona. There a stope ore chute, man-way, timber way and timbering are shown, also faces of ore in place, slabs weighing a ton or more each beng brought from Arizona. Specimens are exhibited of tenorite and melaconite in kaolin, chalcocite and pyrite, chal- copyrite and bornite. cuprite and mal- achite in iron oxide and kaolin. This exhibit cost s10,0O0
 Iron mining is shown by workings of the Lincoln mine at the great Mes sabi range. Minnesota.
 The black coal mines seem gloomy when contrasted with the bright ores of the Copper Queen. Reproduction of the anthracite mines of Pennsyl- vania and the bituminous mines of Kentucky. West Virginia Wyoming, and Washington contain various coal cutting machines, electric locomotives. drills, cars, safety exit. manway, au tomatic mine door, and other appli- ances used in such mines.
 With the cooperation of the Amer ican Smelling & Refining Co., the Anaconda Copper Mining Co. Phelps. Dodge & Co, the International Nickel Co, the Thiogen Co, the Braun Cor poration, and the Nevada Mine Own CTS Association, the l.. s. Bureau of Mines has fitted up a complete test ing laboratory Shelter fume inves- tigation and cyanide problems are the principal subjects at present In the former, the solid particles have been studied, while the gases are yet to be investigated. The apparatus includes Braun laboratory appliances, a model playhouse given by the Mammoth Copper Co.,; from the Western Precip- itation Co. came a model of an in stallation at the Trail smelter, ill British Columbia, and working unit capable of dealing with 300 cu. fit of gas per minute: a Wedge multiple hearth roasting furnace: a Dwight Lloyd sintering machine and product; and a complete assaying and chemi- cal laboratory. For instruction of vii sitors various mill and refinery pro- ducts from the Homes.ake mine, plans of smelters. and assaying are describ- ed graphically.