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Field Museum of Natural History 



DEPARTMENT OF GEOLOGY 

 Chicago. 1922 



Leaflet Number 1 



Model of an Arizona Gold Mine 



This model represents a small gold mine of med- 

 ium richness in a vertical quartz vein six feet wide. 

 The vein and mine workings are presented in section, 

 that is, as they would appear if they were cut through 

 along the center of the vein and one-half removed. 



This model is intended to illustrate the ordinary 

 features present in some form in the great majority of 

 all metal mines and to show the orderly manner in 

 which mines are developed and the ores extracted. 



Great diversity in the nature and structure of ore 

 deposits compels a corresponding variety in the details 

 of workings by means of which the ores of these de- 

 posits are extracted. 



However diverse these details may be, they all 

 may be grouped as parts of major features which are 

 common to nearly all metal mines. 



In this respect these excavations resemble the 

 more familiar structures on the surface. As build- 

 ings, however much as they may differ in appearance, 

 are all built up of units, as walls, floors, windows and 

 doors, so these underground workings are composed 

 of groups of such units, as drifts, cross-cuts, stopes, 

 raises, etc. 



There are some exceptions to this rule. The great 

 open-cut mines of the Great Lakes Iron Ranges, for 

 instance, are merely great quarries. In certain de- 

 velopments of caving systems of mining some features 

 of the ordinary type are nearly unrecognizable or 

 quite absent. Coal mines and mines worked along the 



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