166 



GEOLOGY OF TONOPAH MINING DISTRICT, NEVADA. 



PRODUCTION OF GOOD ENOUGH VEIN. 



The only place on the hill from which much ore has been obtained was from 

 one section of the surface portion of the Good Enough vein. According to the 

 Annual Report of the Director of the Mint on the Production of Precious Metals 

 for 1901, the vein had produced and shipped $15,000 worth of ore up to the 



time of the publication of that re- 

 port. Not much further work has 

 been done on this ore body. 



VEIN STRUCTURE. 



The condition of the Good Enough 

 vein as seen in the chief working 

 shaft is shown in fig. 56. From the 

 standpoint of origin this vein is in- 

 teresting, as it shows plainly the 

 effect of fracture planes, in determin- 

 ing not only the walls, but in pro- 

 ducing a diminution in the size of 

 the vein and even a change of course. 



There is no faulting in the section 

 shown in the figure, and the change 

 in size and dip of the vein is due 

 simply to the control of the original 

 mineralizing circulation first by one 

 and then by another set of fractures 

 (fig. 57). This is in accordance with 

 the observations made on the Miz- 

 pah Hill veins. 



GOLD HILL SHAFT. 



The Gold Hill shaft at the time 

 of the writer's visit was 490 feet 

 deep, in earlier andesite of an unusu- 



fractures. ally fresh character for this district. 



The workings consisted of crosscuts to the north and south at this level, of 30 

 feet each. There was another level at a depth of 300 feet, and a drift '20 feet 

 to the north and 50 feet to the south. The north drift at this level showed a 

 2-inch vein, running N. 80 W. and dipping north at an angle of 67. 



Scale 

 10 20 



30 feet 



FIG. 56. Section of Good Enough shaft. Gold Hill. Lower out- 

 lines of shaft indicated by dotted lines. Shows eross section 

 of vein in early andesite, with minor cross walls. Also 

 shows the control of the size and direction of the vein by 

 dominating fractures, straight lines represent some of the 



