GOLD MINING IN OOLOEADO. 501 



Since the present superintendent, Mr. A. N. Eogers, undertook the man- 

 agement of the alFairs of this company in 1865, they have spent about $100,000 

 in improvements ; their product in that time is not definitely known to the 

 writer, but is considerably in excess of that sum. According to Mr. Rogers, 

 the proceeds of the mine during the year previous to August, 18G9, were 

 some $25,000 or $30,000 in excess of the costs of working. 



Sterling Mine. — Next east of the Bobtail Company's mine is that of the 

 Sterling, owning 66i feet. This claim is opened by a vertical shaft which has 

 reached the greatest absolute depth of any on the lode, and is used by the Drain- 

 age Company as a pump-shaft. The mine has been worked out above, but, 

 when seen by the writer, previous to the suspension of work, there was a very 

 good vein in the bottom, carrying a seam of compact iron and copper pyrites, a 

 foot or more in width, besides a belt of stamp-rock of good quality. The 

 ores are essentially of the same character as those of the neighboring mine 

 just described. During the year previous to closing the mine something over 

 150 tons of smelting ore had been sold at the Smelting Works, on which the 

 mine realized about $90 per ton, in currency, its average tenor being about 

 six ounces of fine gold and six or seven ounces of fine silver to the ton. The 

 mine has good ground, but, as has been just observed, it is too short in extent 

 to be worked advantageously. Its hoisting power is derived from the engine 

 on the next claim on the east, the Black Hawk Company. 



The pump of the Drainage Company, established in the Sterling shaft, 

 consists of a 10-inch force-pump, or plunger, which is placed about 250 feet 

 below the adit-level ; this level, 130 feet below the mouth of the shaft, passes 

 through the mine of the Bobtail Company, as may be seen in the section, and 

 delivers the water in the ravine, west of the Bobtail works. Below the plunger- 

 pump is a draw-lift of 12 inches diameter, raising the water from the bottom 

 of the mine to the cistern supplying the force-pump. The column above the 

 plunger is a 10-inch pipe, except where, for want of a sufficient supply of the 

 latter, two 6-incli pipes are introduced as a substitute. The driving power, 

 set up in the shaft-house at the surface, consists of an engine with a cylinder 

 14 inches in diameter and 30 inches stroke, geared directly to the shaft car- 

 rying the driving pinion, but, owing to several miscalculations, and partly to 

 the lack of proper steam capacity in the boiler provided for the purjDOse, it 



