DRILL PROSPECTING.

Otago Witness, Issue 1343, 25 August 1877, Page 4

DRILL PROSPECTING.

A very important experiment i 3 about to be tried, and should it prove a success, will revolutionise the gravel operations of the entire State. The progress of the work will be watched, from inception to termination, with more than usual interest. The undertaking ia understood to be well backed by San Francisco capital, j and the prime movera are full of confidence as to the final result. The incorporation is known as the Pliocene G. M. Co. (B. S. Thurston, Supt.), and ha 3 been organised for the prospecting and working of certain gravel deposits, situated between Dowuieville and Forest City, Sierra County, California, and supposed to be the extension of the famous Bald Mountain channel. The proposed new system of working will bo by boring instead of tunnelling, the object being to define the exact position of the channel before incurring the expense of sinking shafts and running tunnels, which too frequently strike wide of the

mark intended, thereby causing long delays and heavy losses. The tools used are designed and manufactured by Mr Chas. Oester, of San Francisco, and are in most respects similar to those employed in the oil wells of Pennsylvania. The auger is said to bore -.through clay at the rate of 70 feet in 24 hours, the drills averaging through ordinarily hard rock or boulders about one foot per hour. The channel is expected to be found at a depth of 500 feet from the surface. As soon as its position is determined by the drill, a three-compartment working shaft will be lowered, and the requisite machinery erected.