Year: 1879

In this letter, says Tribune corre- spondent, writin; from the gold regions, it is my purpos to explain how it is possible to min and mill ore in the Black Hills at cost of less than $5 ton, and in on@nstance for about $2 ton. The ledge or belt of ore, as it passes through te range of hills nearly in north and snth direction, crops out at the top of eao mountain, and is cov- cred on the sidesonly by thin layer of drift and soil. When this is stripped off the vein is exposed to view in the form of grea quarry of red quartz from fifty to tw, hundred feet wide, and bounded on eao side by wall of slate of nearly the ssme color, standing upon it's edge at an sngle of 51 degrees.

 This quartz rock, which is all ore and which may be blasted out as easily as rough stone for building or road mak- ing is obtained in the East, IS all sent to the mill and crushed without selec- tion, and even If tramways had to be laid up to the face of the quarry and the ore had to be loaded upon cars by hand, the expense would not be great. But in most of the mines, even the cost of handling and loading is reduced to a minimum in the following manner: In developing mine it is customary to construct tunnels, some of which cut the vein at light angles while others follow the general direction of the ledge. If the tunnel .uns across the vein, drifts or passage-wgs are cut at right angles to the main tunnel, which, of course, follow the general direction of the lode. One of these tunnels, starting out at 8 point on the tide of the hill nearly level with the feG1ers of the stamp mill in which the or, is to be crushed, is driven in directly Ieneath the open cut or quarry from which the ore is to be taken, and winze or shaft from the surface of tle rock is opened perpen- dicularly to the tunnel. A tramway leading to tie mill is built into the tun- nel, and clntes, similar to those by which coel b loaded into cars or vessels, are built at the bottom of the winze. AS the men blast out the rock or loosen it with their picks, they push 1t down through the shaft, and, being caught by the chutes, tits allowed to slide into the cars which ae placed immediately un derneath.

 All of the hines on the great belt arc worked by this method. l do not mea1 to say that none of the ore of these great mines has to be loaded into the cars by hand. The managers of every mine, i they work it properly, develop at leas as much new ore every month as they take out. Otherwise the mine migh stop producing some month, not because it contained no ore, but because it wal not accessible. This development il effected by extending or constructing new tunnels, drifts and cross-cuts, ant the ore or waste that is taken out o these has, of course, to be loaded int cars by hand. Some mines, too, take much larger proportion of their ore iron the open ledge than others. The work ings of the Deadwood Mine, for in stance, for the month of July were en tirely above ground, and all of the or taken out was delivered in the car through a winze such as I have de scribed. This mine was therefore work ed cheaper than any other in the Biacl Hills; the cost of mining and milling 4,3OO tons of ore being stated to me 0 less than $8,000, or considerably les than g. ton. In other words, tn profit on every ton of ore taken out wal more than $8.