SILVER MINING IN COLORADO. 619 



" gouge," is a siliceous and feldspathic mixture, not very hard, somewhat 

 broken or cut by seams and clefts, and stained with iron. The pay-seam is 

 from 6 to 12 inches wide, and occurs sometimes on one side, sometimes on 

 the other side of the vein. The ore is chiefly argentiferous galena, two or 

 three varieties of blende, some argentiferous gray copper, sometimes quite 

 rich, some ruby silver, and other rich silver minerals. The gangue minerals, 

 • intimately associated with the pay-ore, are heavy spar, quartz, spathic iron, 

 and others of less frequent occurrence. The vein is drusey in character, and 

 vugs, or cavities with crystalline linings, are found often. The pay-mineral 

 appears to occur in bodies, which are continuous for long distances, both 

 horizontally and vertically, so far as known; sometimes, indeed, pinching up 

 to a thin seam, making the vein almost barren, and then expanding to 10 or 

 12 inches. In one place, on the lower level, a width of over two feet of 

 galena was maintained for a length of 20 or 30 feet. The continuity of 

 the pay-seam, maintaining a fair average width for considerable distances, 

 appears as one of the notable features of this lode. The value of the ores of 

 this vein is often quite high. Selected lots have yielded large returns by 

 assay ; the greater part of that which has been worked, however, is first con- 

 centrated on dressing machinery, by which means the galena, the blende, 

 and gray copper, with silver sulphurets, are obtained separately. Owing to 

 the absence of suitable smelting or metallurgical works, the last two pro- 

 ducts, the blende and copper, had remained unworked up to the time of the 

 writer's visit; the galena, or lead mineral, had been smelted, and it appeared 

 that the average value of this dressed minei'al was between $150 and $200 

 per ton. 



The ground in the vein is comparatively soft. Drifting costs from $6 

 to $10 per foot. Stoping, $17 to $20 per fathom. The walls stand well, 

 and the cost for timbering is not great. As the mine is, and for a long time 

 to come may be, worked by tunnels, the actual costs of mining are tolerably 

 light. The ores and rock broken in the mine are brought out to the surface 

 through the tunnels, and there assorted. The poor is thrown away and the 

 ■workable ore sent below to the mill, by means of a gravity road, lately con- 

 structed on the hill-side. 



The methods of reduction proposed for the ores of this mine consist of 



