Chicago : Engineering and Contracting Pub. Co. · leaf 312
Sinking an Inclined Diamond Drill Hole. When diamond drilling explorations are un-lertaken from the surface a stand pipe mustie sunk to bed rock or ledge through the over-ling soil. This will vary in depth from aew feet to several hundred feet. Mr. W. T.toberts in Mine and Quarry describes a… … Diagram Showing Survey of Hole DrilledNear Ogdensburg, N. Y. lorizontal and sunk through a deposit of sandmd gravel, quicksand, boulders, and a mixture)f mica and sand. The ledge was finally■eached at a depth of 372 ft. at which point1 test of the angle of the pipe showed 44°.rhe accompanying…
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