586 MmiNG INDUSTEY. 



are managed by skillful and experienced men, and, it is said, have been profit- 

 ably conducted. The establishment has been and is of great advantage to the 

 district, affording, as it does, the best and almost the only suitable method of 

 treatment that has yet been introduced for the first-class ores. 



The first shipment of matt was made from these works in June, 1868. 

 A complete statement of the shipments since that time is not in the writer's 

 hands, but from available data may be estimated at about 25 tons of matt per 

 month, containing, on the average, 40 ounces of fine gold, 200 ounces of fine 

 silver, and 40 per cent, or 800 pounds of metallic copper, per ton. This is 

 equal to 1,000 ounces of gold, 5,000 ounces of silver, and 20,000 pounds of 

 copper, per month. The gross value of these metals, thus shipped, is about 

 $30,000, coin, per month, or $570,000 from date of beginning to January 1, 

 1870. 



Chlorination Works. — These works were estabHshed in this district in 

 1868, by Mr. Cash, a gentleman who had already had a considerable expe- 

 rience at Grass Valley, in California, in the treatment of auriferous pyrites by 

 the chlorination process. It is the purpose of this process to extract the gold 

 by first converting it from the form in which it exists in the ore into that of 

 the soluble chloride, obtaining this in an aqueous solution, and then precipi- 

 tating the gold, in the metallic state, by the sulphate of iron. This process 

 has been successfully employed in Europe during many years, and was intro- 

 duced in California about ten years ago, where it has given great satisfaction. 

 It w^as brought to Colorado by Mr. Cash with the purpose of treating tailings, 

 but owing to various hinderances had not entered upon regular operations at 

 the date of the writer's visit in 1869. One cause of this delay is said to be 

 the low value of the material to be treated, the tailings having been formerly 

 supposed to be much richer than now appears to be the case. It is now 

 reported that the establishment will be provided with some suitable crushing 

 machinery and be employed in the treatment of first-class ores. The works^ 

 consist of one reverberatory furnace in which the ores are subjected to a 

 chloridizing roasting ; four large chlorination vats, or tubs, in which the roasted 

 material is subjected to the action of the chlorine gas; the necessary apparatus 

 for generating chlorine ; two precipitation tubs, in which the gold is thrown 

 down by sulphate of iron; and a small melting furnace, for running the metallic 



