GOLD MINING IN COLOEADO. 



545 



a source of great profit to tlie owners. Its ore is chiefly iron pyrites, yielding 

 from one to two ounces of crude bullion per ton. 



"Winnebago Lode. — On the opposite side of Eureka Gulch, and further 

 east, is Casto Hill, the location of an actively-worked and promising mine, be- 

 longing to the Barrett Mining Company, and opened on what is known as the 

 Winnebago lode. This lode, nearly parallel to the Gunnell, has about an east 

 and west course, dipping vertically, or somewhat inclined to the south. The 

 Barrett Company own 400 feet and have worked it by means of a single shaft 

 some 300 or 400 feet deep. This shaft has passed through variable ground, 

 having encountered "cap" or barren rock at about 100 feet from the surface, and 

 striking pay-ground again 100 feet deeper. The ground is opened by levels and 

 worked by backstoping. About one-third of the rock broken is said to be good 

 for stamps, and much of the poor rock is selected below ground and left on the 

 stulls. The ore is chiefly iron pyrites with but a small proportion of copper. 

 The presence of free gold is frequently noticed. The present manager treats 

 all his ore by the stamping process, though some experimental lots of first- 

 class ore have been selected for other more exact methods. One such lot of 

 24 tons gave, by assay, 4 ounces of fine gold and 4 ounces of fine silver to the 

 ton. The whole mass, when stamped, yields on an average 4 ounces, or $64 

 worth, of crude bullion to the cord, or about $8 50 coin, per ton. The tail- 

 ings, after leaving the mill, are said to assay 1 ounce or more to the ton, and 

 are reserved for further treatment. The mine is furnished with hoisting 

 power, consisting of an engine, the cylinder of which is 14 inches in diameter, 

 and one boiler of adequate capacity. The winding apparatus is the common 

 spool, driven by belting and controlled by a friction-brake. The water is 

 raised in a barrel by this means. 



The machinery is set up at the mouth of the shaft and drives a fan- 

 blower for ventilation, as there is but one shaft. A 20-stamp mill is set up 

 in a wing of the same building and driven by the power just described. The" 

 stamps weigh 500 pounds each and drop 18 inches 28 times per minute. 

 They crush about 2 cords, or 15 tons, per day. Milling operations commenced 

 in July, 1868, and are said to have been conducted with profit. The conve- 

 nience of the mill to the mine, and the economical arrangement of the whole, 



affords some advantages for working at a low cost. 

 69 



