530 MINING INDUSTET. 



The lode, as shown in the Clark-Gardner mine, is a large and regular 

 vein. Its width is seldom less than 3 feet and often 10 or 12. Its walls 

 are smooth and well defined, standing firmly, and involving but comparatively 

 little expense in timbering. 



The ore, as in the veins already described, is a mixture of iron and cop- 

 per pyrites, carrying, however, a considerable proportion of galena and zinc- 

 blende. The valuable mineral appears to be more widely diffused throughout 

 the general filling of the vein than generally observed elsewhere ; for while 

 there is usually a compact seam of pyritous ore, it is almost always narrow, and 

 the proportion of high-grade ore, worthy of selection for smelting, is very small.^ 

 During several months of 1868 not more than 20 tons of first-class ore had 

 been selected from 1,500 or 1,600 tons of ore produced, equal to one in about 

 80. To compensate for this there is a good degree of uniformity existing in 

 the quality of the milling ore, and occurring, as it does, in a comparatively 

 wide vein, it can be extracted cheaply. The main filling of the vein is a 

 siliceous and feldspathic mixture, but where the vein is wide there is frequently 

 what appears to be an inclosed mass or "horse" of country-rock, granitic in 

 character, though carrying an impregnation of pyrites through it. In the 

 Clark-Gardner mine one-half or two-thirds of all the vein-matter broken is 

 sent to the stamping mill, and yields, on an average, about 6 ounces of crude 

 bullion, or $100 coin per cord, equal to $12 or $14, coin, per ton. 



The proportion of first-class ore of the Clark-Gardner mine has already 

 been shown to be small. The sale of this quality to the Smelting Works 

 amounted, in eight months of 1868, to 38 tons, averaging 3i ounces of fine 

 gold and Hi ounces of fine silver to the ton. 



The Clark-Gardner mine, 200 feet in length, is opened by two shafts, 

 the westernmost having reached a depth of about 360 feet. The ground near 

 the surface was generally unproductive, but at the depth of 80 or 100 feet a 

 good body of pay-ore was encountered, and the mine below that, excepting 

 some poor spots, has been mostly worked out to a depth of 300 feet. The 

 costs of working the ground are comparatively light. Drifting costs from $5 

 to $10 per foot ; sinking, 8 feet by 5, costs $20 per foot ; stoping, from $12 

 to $22 per running fathom. Much of the ground in the lode can be picked 

 down, and comparatively little powder is required. Two men have broken a 



