THE OOMSTOOK MINES. 115 



station above is reached, each floor being kept a little in advance of the one 

 next above, as indicated in the drawings on Plates IV and V. 



When it becomes necessary, on account of the unsettled character of the 

 ground, or for other reasons desirable, to extract the body of ore as speedily 

 as possible, it is not uncommon to commence at the same time a floor on the 

 level of the station and another floor halfway between the given station and 

 the one above. For this purpose a winze is sunk from the upper station to 

 the one below. From this winze the stopes are started, one on the lower 

 station and one 50 feet higher. The lower series of floors, usually six or 

 seven in number, rising one above the other, arrive at length directly under 

 the 50-foot sill, as the lower floor of the upper series is termed. By this time 

 the mass of timbering is held in place by lateral pressure with sufficient 

 security to allow of introducing, without difficulty, the timbers to be placed 

 directly under the 50-foot floor. Fig. 1, on Plate IV, is an illustration of this 

 proceeding. The main body of stopes, visible in the drawing, have been 

 started and carried on from the winze, W, that connects the upper with the 

 lower level. The stoping on the extreme left has proceeded in similar man- 

 ner from another winze, further to the left, the stopes advancing to meet each 

 other. After the available ground has been exhausted the plank of the floors 

 are removed for use elsewhere, and the vacant chamber filled with waste 

 material. 



The expense of this work is, of course, very great, both for material 

 and labor. The cost of the timber is from $30 to $40 per thousand feet,-^ 

 board measure, and the consumption is enormous, making the timbering one 

 of the largest items of expense in the Comstock mines. 



In the Grould and Curry the costs of framing (by hand) the mining 

 timbers just described were from 46 to 60 cents apiece for posts, 35 to 40 

 cents for caps, 25 to 30 cents for cross-pieces, or girths, and $1 20 to $1 50 

 for sills. Shaft-timbers cost, at same mine, framed by hand, about $20 per 

 set ; tunnel-timbers $1 to $1 50 per set for framing alone, not including any 

 costs of placing under ground. 



In the Gould and Curry, in 1864, the supply of timber for use in the 



^ These prices liave been reduced since the completion of the Virginia and Truckee 

 railroad. 



