BORING FOR QUARTZ REEFS.

Tuapeka Times, Volume III, Issue 148, 8 December 1870, Page 6

BORING FOR QUARTZ REEFS.

(To the Editor.) Sir, — Some time since I read an account of Mr. Skey's discovery of an improved mode of testing the quality of quartz reef stone, by which it appears he is enabled to trace gold, however small the quantity may be, brought under his tesf;, and to form a calculation of the probable return, ranging at ldwt. of gold to one ton of quartz. This discovery, I think, removes the only difficulty which stands in the way of the adoption of the following plan, which has for its object the facilitating of prospecting for quartz reefs. As quartz reeffing at the present time is engaging the attention of a large portion of the mining community of Otago, to them especially I respectfully submit my ideas for consideration, in the hope that my remarks may prove interesting as well as useful to some of your readers. My plan is to facilitate the testing of quartz reefs, in so far as to do away with the expensive and tedious plan of sinking prospecting shafts, and adopt boring, as an easier, less expensive, and at the same time as thorough a test, as the present mode of shaft sinking. A quartz reef being discovered, the radius, depth, and quality of such could be ascertained, without involving any heavy outlay, by sinking a hole in the usual way, to ascertain what is termed the dip, or lay. This being got, the services of a practical surveyor may be requisite to properly define "the point the prospector wishes to commence his first bore — say to cut the reef at 50 feet, or 100 feet. This being done, and boring commenced in the usual way, with the common boring apparatus, which can be easily obtained here, should the reef be cut at less than 50 feet, it will show a less angle. The nature and character of the reef at this point can at once be v ascertained! and on a prospect being

got, if it prove payable, a second bore can be proceeded with at another point, say at a distance of one or two chains from the first bore, and so continued, testing the reef for one mile, or ten, as may be required. The testing of the borings can be proceeded with as follows : — The size of the drill used will be, say, 3 inches diameter. In most localities on the Otago goldfields two men will sink from 3 to 5 feet per day, to the depth of 100 feet. As the borings are raised after the reef is struck, they can be tested, not only every foot, but every inch. Should the borings prove when tried not of such consistency as to stand removal, they can be carefully put into bags or packets, and can be forwarded to any part of the globe. The length of said packets to be, say one foot ; the width, the size of the bore. Should a sample be required from any single packet, a small sampling iron can be inserted that will draw one-third or one-fourth, or as much as may be required of the contents of the packet, to form a sample. The drainage water, hitherto, has always proved a great difficulty in the way of shaft-sinking in Otago, The following may show how this difficulty may be partially, if not wholly removed. In the event of a shaft being sunlc on a reef prospected by the mode explained in the foregoing, a shaft should be sunk to the depth of the bore previously sunk. The water for the first 28 feet can be raised to the surface by an ordinary sucker pump. This is the utmost depth water can be drawn by this means, but if the sinking of the shaft can be continued beyond this depth by using a pump of this description, one can be inserted down the bore, say 12 feet. The man at the winch on the surface can work it, with the assistance of a small rod to reach the pump. The water so pumped can be conveyed by a bucket from the bottom of the shaft to the surface. This mode can only be adopted where the volume of water is not so great as to prevent the working of this simple appliance. Should the drainage be so heavy as to necessitate the application of a force pump, the hole being previously bored, the bottom of the pump can be placed in the bore, so as to keep the water four or five feet below the party sinking the shaft.

The bore, while the shaft is in progress of sinking, more especially should blasting be required, will, in all likelihood be liable to get partially filled with debris. In this case the bore can easily be cleared by the insertion of one or two of the boi'ing rods into the tube. Having inserted in it a selfacting valve belonging to the boring apparatus, the party sinking, by the use of a small rack-wheel, will be enabled to turn the rods and draw any debris that may be in the bore to the bottom of the shaft, after which such matter can be conveyed to the surface in the usual "way.

Being an old Bendigo quartz-reefer, the ideas laid down in the foregoing have engaged my attention for several years, but as until lately no process had proved successful to test a small quantity of quartz such as could be obtained by boring, I refrained from giving publicity to my ideas. But, as I remarked above, Mr. Skey, by his late discovery, has removed this difficulty. This discovery, it is to be hoped, will give such an impetus to quartz mining as will place it among the most prominent and flourishing branches of gold mining in Otago. — I am, &c, James Sandisox. Waikaia Bush.