CHAPTER V. 



OTHER GROUPS OF MINES. 



MINES AND PROSPECTS IN THE LEADVILLE REGION. 



It is from the mines included in the three groups ah-eady described that 

 what may be considered the permanent ore supply of Leadville has been 

 thus' far derived, and it is in these mines alone that exploitation has been 

 carried on so continuously and extensively as to afford an opportunity to 

 study in detail the- character and the form of the different ore bodies and 

 their relations to the inclosing and neighboring rocks. For this reason they 

 have been described with a detail that may, iu the future, seem dispropor- 

 tionate to their relative importance, especially when, as is likely to be the 

 case at no far distant day, the deposits of these limited areas shall have 

 become nearly exhausted and the main supply is derived from what ma}' 

 now be considered outside ai-eas. From the evidence obtained during this 

 study it is fair to as.sume that a greater amount of as yet undiscovered ore 

 exists outside these areas than has already been developed in the small 

 groups already described, and that, while its exploitation will necessarily 

 be more difficult, owing to greater depth and large influx of water, and its 

 reduction will require more complicated processes, owing to a greater pre- 

 ponderance of sulphurets, these disadvantages will be offset by greater ad- 

 vantages of working, brought about by a more thorough knowledge of the 

 geological relations of the ore deposits and by improvements introduced 

 into the various processes of reduction. 



With but few exceptions these outside mines have been hitherto but in- 

 termittently worked, and, owing to some minor differences in the character 



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