Douglas Island news., 1903-11-04

enC to nave large storage CapaClCy dG the stations, and when the ore-bin is in the ore 1t is just as economical to cut a large as a small one.
 In the Mexican and 700,Foot mines, the main cross cuts start directly from the shaft, and as a consequence the station-cutting is much simplified. In other respects they follow the same system as the Treadwell, with the ex- ception that the ore-bins are smaller, and in the Mexican two bins are cut one for ore in front of the shaft, and one for waste, cut on the opposite side of the shaft and reached by an exten- sion of the main cross-cut.
 Ia the Ready Bullion mine the above methods are used, but are changed in so far as to make them applicable to an incline-shaft, with the further excep- tion that the main cross.cut runs to the hanginG-wall. In cutting out the ore-bins two methods are employed. The old one consists of putting up a raise from the chute station to the level and after the chutes have been built to cut around the raise from the level of the cross-cut until the bin is of the required dimensions. By this method the rock is broken into large pieces and has to be "bull-dozed" with powder and drawn out before the work of drilling can be continued. The second method is to put up raise from the chute station to the small drift from the shaft to the station level, then build in the chute and stope out a room the size of the bin. The stope Is carried to the level of the top of the main cross-cut, thus saving the ex- pense of from 40 to soft of cross-cut- ting. At the same time it protects the timbers of the shaft from flying rock by leaving a small pillar between tho ore-bin and the shaft, which can be removed when the bin is finished and the face of the cross-cut sufficiently far away to insure the shaft-timbers from being broken when the cut is blasted. The system of stoping is the same as that employed in the large stopes.
 LEVELS (DR1FTs, CROSS, ,CUTS, WIVES, Ere. ).-When the ore-bin and station are completed, the main cross-cut is driven to the footwall. It thus serves the double purpose of determining how the level can be developed in the most economical way and of permit ting a thorough sampling of ore, so that fair idea of it's value can be ob- tained. The following rule is almost automatic in its applicability to the ore- bodies on the island: Start the first drift along the footwall, and keep it there. At various times the above rule had been ignored, and always with the same result. The ore-body is subject to abrupt changes in the strike and dip of the footwall. It is impera- tive that the ore be drawn from the stopes by gravity, and this cannot be applied to the ore along the foot wall unless the chutes, and consequent ly, the drifts, are kept as close to it as possible.
 On 22-level the slate-horse in the center of the deposit is quite small, and therefore more drifts than usual are required. On the lower levels, where the slate-horse is wider, is is left in place and forms a natural division between the hanging and footwall DOT tions of the ore-body. At intervals of p feet raises are put up on alternate sides of both the main cross-cuts and drifts. These raises are 15 feet high and are designed to accommodate the chutes for drawing the ore from the stopes. They are put up while the drift is run, and given slope of 60 degrees from the horizontal so that the ore will run freely in them. In the Treadwell, Ready Bullion and 7OO-Foot mines, the drifts and chute raises are in ore; but in the Mexican, on account of the fiat ness of the vein, they are run in the footwall slate, and the chute raises put up to the ore at an average height of 20 feet above the track. At the same time as the main drift and the chute-raises are being run, second drift, called the intermediate, is driven directly above the main drift and separated from it's back by pillar of rock 10 1t. thick. This drift is the same size as the lower one, and is so driven that it