ROCK DEILL.

Tuapeka Times, Volume III, Issue 219, 11 April 1872, Page 9

ROCK DEILL.

llicre was exhibited in the machinrry department at the recently held Mechanics Fair (San Francisco) an invention which, if thorough experience proves it to be without disadvantages, vow uuforseen, will work a revolutution in tlie cost of rock mining. It is a rock drill, invented and patented by Dr A. Blatchloy. Dr BUitchley is a miner of many years' experience, and seen * the necessity of a simple, effective, and cheap method of drilling by machinery, five years ago commenced studying to supply the deficiency. He spent considerable time before he was able to construct an apparatus which answered Ins idea of the requirement. His difficulty was to obviate the destructive effect of the recoil. The machine, as now perfected, is 22 inches in total length, excepting the drill ; height 8, width 5, excepting the flanges, which are 10 inches. The weight is 76 pounds. It can be operated in any tunnel or shaft where one man can enter. It rests on a plank the end of which extends from side to side, the plank being somewhat longer than the tunnel is wide, affording a firm rest. It can be conveniently placid in any position, so as to drill a hole in any direction or point, whether in the face, side, or top. It is wholly unlike any other rock drill, both in principle and construction. Its blow' is that of the churn drill. It gives from 300 to 400 per minute, the force being only limited by the sustaining force of the drill point. It feeds itself, the drill being pushed forward as required.. With each blow the drill is slightly turned. The motive power may be steam, compressed air, water or horse power. It requires from half to a whole horse power to run it. The shafting is constructed with universal joints, so that the machine can be moved without changing the position of the motive power. Dr Blatchloy has also invented a universal gear, by which two lengt'is of shafting can be worked at acute angles. The drilling point is made with five leaves instead of two, the ordinary number. It is made by the aid of a die. By means of this drill the power of a hundred men can be concentrated in a tunnel. The operation need not be suspended while the debris is being cleared. A miner ordinarily strikes 20 blows per minute, this will strike 500. In an ordinary tunnel but four men can be kept at work by hand drilling. In the same tunnel four or five of these machines can be operated at the same time, and one man can attend them all if the rock is hard, so that they do not need frequent adjustment. Any miner of average intelligence can operate it after a little showing. Two of these are in practical opVation at the Fair. The first one made has-bored over 2000 feet, and shows not the least signs of giving out Tt has been operated in various tunnels, and anong others, in theDaney mine, below Gold Hill, Nevada. In a granite boulder,- at the Fair, it drills a hole 2£ inches in one miuute. — "Bulletin. "