26 Colorado Gold Mines. [January, 



can only be worked at a loss, which is calculated by Mr. 

 Reichenecher at 1*73 dols. per ton. 



Most of the mines which have been kept open on the 

 lodes previously enumerated are of the first class. Many, 

 of course, have yielded much higher percentage ore than 

 the average : many more have intermitted between poverty 

 and richness ; and there is many an isolated mine, like the 

 California on the Flack Lode, which has for many con- 

 secutive months by its large returns effected the prosperity 

 of the whole region. There are, moreover, first class claims 

 held by wealthy men who can afford to wait, and who have 

 kept them closed for years, sure of the introduction sooner 

 or later of more economical methods of treatment. Of each 

 there are several on the Bates Lode. The best evidence of 

 the unparalleled richness of these mines is that, despite the 

 loss of 66 per cent of their mineral, so many have been for 

 years worked to advantage. A comparison of their produce 

 with those of other gold-producing countries affords further 

 proof of this.* The average value of 500,000 tons of 

 Australian gold quartz was 16*78 dols. ; the average value 

 of ore raised in eight counties in California from 30 mines, 

 including the richest, is, per ton, 23*50 dols.; while 1,760,050 

 tons from the Morro Velho mines, Brazil, yielded only 

 8*20 dols. per ton, and yet the ores of Gilpin County must 

 yield 25 dols. in gold to cover cost of extraction and milling 

 alone. If the character of the ore is so peculiar as to defy 

 all known methods of economical treatment, the mines must 

 be left to their inevitable fate. But there is no reason to 

 apprehend such a gloomy future. 



The remedy evidently lies in mechanical concentration of 

 the second and third class ores, the abandonment altogether 

 of battery amalgamation, and the smelting of the whole 

 produce. 



The ore should be carefully assorted by hand, and a 

 separation made not only of first class, as at present from 

 the poorer vein stuff, but of the iron and copper pyrites 

 from the galena and blende. 



First class ore, as at present, is fit for the furnace, and 

 can be roasted either in heaps, or, better still, in kilns ; for it 

 is a serious waste of capital to have 100,000 to 200,000 dols. 

 worth of ore lying in roast heaps for months, when the 

 amount might be returned in as many weeks were kilns 

 employed. Second and third class ore, the former of which 

 alone is now serviceable, might both be crushed and 



* Baker's Pamphlet, p. 15. 



