10 RESURVEY OF CRIPPLE CREEK DISTRICT. [BULL. 254. 



Hand sorting and washing, the latter in order to separate the fines, are 

 the methods employed. More care is now taken than formerly, but 

 at many places there is still room for improvement. 



The district contains many large mines operated by strong compa- 

 nies, but the system of leasing to individuals and small companies, with 

 royalty charges of 15 to 25 per cent of the net output, remains a 

 conspicuous feature. At the present time the mines of the north- 

 western and northeastern parts of the district are only slightly pro- 

 ductive. Among the formerly highly productive mines in this section 

 may be mentioned the Victor, Isabella, Wild Horse, Damon, Logan, 

 Orpha May, Pharmacist, C. O. D., Gold King, and Anchoria-Leland. 

 The southwest quarter of the district contains the active and impor- 

 tant El Paso, Mary McKinney, and Elkton mines, but the maximum 

 output during the last few years has come from the southeastern por- 

 tion, within which are the Portland, Gold Coin, Ajax, Strong, Golden 

 Cycle, .Vindicator, and Last Dollar mines. The Portland mine has for 

 some time been the heaviest producer in tonnage as well as in value. 

 Its output is from 60,000 to 90,000 tons per annum. In 1903 this 

 mine produced $2,600,000. 



The metallurgical history of the camp is interesting. Beginning 

 with local amalgamating mills, the practice soon changed to local 

 chlorination and cyanide plants. It was soon found, however, that 

 better situations would be found in the valleys, and at present a very 

 large part of the tonnage is shipped to chlorination and cyanide works 

 at Colorado City and Florence. About a sixth of the output, com- 

 prising the higher grade ores, is sent to smelting works at Denver 

 or Pueblo. A still smaller amount is treated in a local chlorination 

 plant near Victor. While in former years the practice leaned more 

 toward the cyanide process, the bulk of the ore is now treated in large 

 chlorination mills with automatic roasters and revolving barrels. It 

 has always been found necessary to roast all except the completely 

 oxidized ores. At the present time there are in the district two small 

 mills in which the cyanide process is used without previous roasting, 

 and which are thus enabled to work ores containing as little as $5 a 

 ton in gold. The extent of these low-grade ores is not yet fully 

 demonstrated. Regarding the value of the ore, see page 21. 



Treatment charges at the mills fluctuate somewhat, but usually range 

 from $7 to $13 a ton, according to the tenor of the ore; in the early 

 part of 1904 the prices were reduced, it is reported, and ranged from 

 $5. 50 to $10 per ton. Recently they have again been increased. On the 

 whole the mining and milling expenses are very high at Cripple Creek 

 compared with those of other localities western Australia, for exam- 

 ple, where similar ores and conditions prevail. Few of the large 

 mines seem to have reduced total expenses below $16 per ton. 



