106 MmiNG mDIJSTET. 



timbers are placed in similar manner, but breaking joints with the sill-timbers, 

 as shown in Fig. 5, which is an end view of the shaft. The partition-timbers 

 are placed like the end-timbers, one upon another ; but their ends are not let 

 into the sill-timbers by any gain or mortice ; the sills are dressed smoothly to 

 receive the ends of the partition-timbers, which are then put in place without 

 any framing. 



The cost of sinking these shafts varies with the depth and the character 

 of the ground. The actual cost per foot is not easily ascertained, because, in 

 most cases, the expense of sinking the shaft is involved, in the accounts, with 

 other general expenses of the mine, so that an accurate and minute analysis of 

 costs is almost impossible. The most carefully detailed statement concerning 

 the costs of this kind of work are found in the books of the Gould and Curry 

 Company. Their shaft is of the same general character as that described 

 above. It is 24 feet long by 4 feet 8 inches wide, inside measurement. The 

 average excavation is about 7 feet by 26. It is divided into four compart- 

 ments and timbered, as generally indicated in the foregoing, with 12-inch 

 timbers, 



From the available accounts of this work it appears that the cost, per 

 foot, of sinking and timbering the shaft, at a constantly increasing depth, was 

 as follows •} 



Per foot. 



225 feet from surface. $70 21 



200 feet next following 100 88 



200 feet next following 135 34 



67 feet next following 189 50 



187 feet next following, in 1867 224 99 



250 feet next following, in 1868 342 65 



1,1 29 feet, costing, on the average A 180 22 



The shaft had reached a depth of 1,187 feet on November 30, 1869, but 

 the cost of sinking during that year is not published in the. last report of 

 the company. 



^ The reader is reminded that these values are expressed in coin. 



