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MINING INDUSTEY. 



line-shafting. The engine, which is used for hoisting at both shafts and for 

 driving a 20-stamp mill, communicates its power by means of a pulley and belt 

 to a 4-inch shaft, which is extended, with diminished diameter, in the direction of 

 the pumping shaft; but as the latter is higher up the hill, some 30 feet or more, it 

 is necessary to disconnect the line-shaft twice, belting upward, in each case, to 

 connect the detached parts. From this line-shaft the power is transmitted to 

 the pump-gearing by means of a pulley and belt. This arrangement is said 

 to work satisfactorily by the engineer in charge, but such a method of driving 

 a pump of so large dimensions and required duty as the one just described is 

 not to be recommended. The shafting is liable to get out of line, involving not 

 only the necessity of repairs, but an interruption in the raising of the water. 

 Powerful tighteners are required on the belts, and when the engine is running 

 stamps and hoisting too, the pump works very irregularly. The pump was 

 built by Hodge & Christie, of Detroit. Its cost for all the iron work was 10 

 cents per pound at the shop ; freight to the mine 9 cents. The total costs of 

 providing and placing the pump and its appurtenances, not including any part 

 of the engine, is stated at $33,000. The engine used for pumping, hoisting, 

 and running the 20-stamp mill is a plain horizontal cylinder of 20 inches 

 diameter by 42 inches stroke, supplied with steam by two boilers, 16 feet long 

 by 4 feet diameter ; burning about five cords of wood per day. 



Hoisting is done by iron buckets, containing about 800 pounds of rock. 

 The winding apparatus is similar to that already described on the Consolidated 

 Gregory, and is operated by means of belting, set in motion by the applica- 

 tion of a tightener, and controlled, in lowering, by a brake. 



There are two stamp mills belonging to the company, one containing 20 

 stamps set up at the mouth of the eastern shaft, and run by the same en- 

 gine that does the pumping and hoisting; and one containing 60 stamps 

 located in the town of Black Hawk, near the mouth of Chase Gulch. The 

 machinery and methods of operation employed in them will receive attention 

 further on when the general treatment of the ores of the district will be 

 described. 



Owing to the lack of statistical information on the subject the writer is 

 unable to furnish such minutely detailed statements as are desirable concern- 

 ing the costs of operation, the yield of the ore, and the production of the mine. 



