154 



SILVER-LEAD DEPOSITS OF EUKEKA, NEVADA. 



of course require some timbers, but usually no more than are necessary 

 for the support of ladder- ways, etc. The Richmond shaft, over 1,200 feet 

 deep, which passes through shale, limestone, and quartzite, is only "cribbed" 

 for the entire distance with two-inch plank, except at the stations, where 

 timbers are used. Timbering, however, will eventually be necessary in this 

 shaft, not only below the water level but above as well. Below the water 

 level the limestone stands very well, owing partly to its nature and partly 

 to the more compact character of the rock as depth is attained. The quartz- 

 ite ought always to be timbered below the water level, and it would be 

 found more economical in the long run to timber all working shafts care- 

 fully. 



Fig. ;. — Set of timbers. 



Method of timbering. — Fig. 8 represents a complete set of rectangular tim- 

 bers, as they are used in carrying up a stope in an ore body. These tun- 



