SUCCESSFUL APPLICATION OF MACHINERY IN MINING.

Grey River Argus, Volume XI, Issue 942, 3 August 1871, Page 2

SUCCESSFUL APPLICATION OF MACHINERY IN MINING.

We take the following interesting article from a Californian paper : —

We U3e steam extensively in hoisting, pulverizing, and concentrating ores ; but hitherto have depended almost entirely upon hand labor for running tunnels and drifts, and breaking down the ore. The Diamond drill tunnelling machine, however, has been tried at Smartsville with success, and we may now consider it an important aid in the development of our mineral resources. It will henceforth be ' in constant and increasing use, unless superseded, and that does not now appear probable, by some superior machine. The Blue Gravel Hydraulic Claim at I Smartsville is one of the most valuable and best managed pieces of mining property in the State. It has yielded at least 1,000,000 dollars, and is expected to yield much more. The company, while washing off the upper strata of the claim, have at the same time been cutting a deep tunnel through which to run off the lower strata. The lower tunnel was cut 1285 ft by hand, at a cost of 40,000d0l and three years' labor. When in 1200 ft, eight men were constantly employed in it, working in three shifts, and making about one foot in 24 hours, at a cost of 40dol per foot, blasting with black powder. The whole length of the tunnel was to be 1663 ft, and as it would be an important point to hasten the work, the company determined to try the Diamond drill.

A machine was made for them in this city on an original pattern, and after many delays incident to the introduction of a new method of working, the experiment is pronounced a success. Fifty feet of tunnel have been made with it, and now that everything works smoothly and the^ Company have sufficient experience to justify the expression of an opinion, they declare themselves satisfied. In the

same kind of rock which before cost 40dol per running foot with black powder for cutting the tunnel six, feet wide and eight feet high, by hand, at the rate of one foot per day, they now cut from two to two and a half feet per day in a tunnel six feet wide and nine feet high, at an expense of 25d0l per foot. This price covers everything save the interest on the cost of the machine and the wear and tear. The power is supplied by a fifteen horse-power steam-engine at the mouth of the tunnel, and is transmitted by compressed air through a hose to the drills, which bore holes an inch and an eighth in diameter at a speed of from half an inch to an inch and a quarter in a minute. The holes are usually from 20 inches to 30 inches deep, and all on the face of the tunnel are blasted out at the same instant by an electric exploder. The chief profit at theßlueGravelmine, z. from the use of the machine, is in the saving of time. The tunnel, which has already cost 40,000d015, would be of no use for ten or eleven months yet if the drilling were done by hand, but with the help of the machine it will be ready for service in less than four months. Here is a saving of the interest on 40,000d01s for six months. Then the Company will get their gold-dust from the mine six. months' sooner, and they will have so much on interest on that. They have other tunnels to cut, and for the purpose of working to the best advantage they have purchased the machine now in use and ordered another. They authorise us to say, that in their opinion, when the men have more experience, and when everything is arranged for the machine in the best style,' it will do much better than at present. The success of the machine in this tunnel implies a success in any tunnel -of eqnal size in hard rock. The larger the tunnel and the harder the rock, the greater the relative saving. We presume that there would be no economy in using a machine to cut a tunnel smaller than at Smarts- : ville, and that is larger than most of the ; mining tunnels need to be. Railroad tunnels are larger, and for them the mar' chine is very valuable. Whether the diamond drill could [be used profitably in stopping or breaking down quartz rock) is a question upon which we are not prepared to express an opinion, but whicn. is worthy of examination.