Author Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1914 Excerpt:...fineness. subject To Revision DISCUSSION OF THIS PAPER IS INVITED. It should preferably be presented in person at the Pittsburg meeting, October, 1914, when an abstract of the paper will be read. If this is impossible, then discussion in writing may be sent to the Editor, American Institute of Mining Engineers, 29 West 39th Street, New York, N. Y., for presentation by the Secretary or other representative of its author. Unless special arrangement is made, the discussion of this paper will close Dec. 1, 1914. Any discussion offered thereafter should preferably be in the form of a new paper.. Quarrying Shale by the Tunnel System BY DWIdHT T. FARNHAM, SEATTLE, WASH. (Pittsburg Meeting, October, 1914) Description of Quarry The shale used at the Renton plant of the Denny-Renton Clay & Coal Co., for the manufacture of vitrified paving brick occurs in a hill rising from 200 to 300 ft. above the level of the valley in which the plant is situated. The shale deposit, which is of unknown thickness pitches about 10 to the southeast. The 150-ft. face worked extends approximately east and west, so that the dip, as shown by the photograph, is to the left and into the hill. The shale is overlain with about 50 ft. of gravel, 70 ft. of clay, and 30 ft. of mixed loam and gravel, making altogether from 125 to 150 ft. of overburden. Disposal of Overburden The overburden is removed by sluicing. For this purpose a No. 2 Joshua Hendy giant is used, throwing a lj-in. stream, and having 60 lb. pressure at the nozzle. The water is drawn through an 8-in. pipe from Cedar river, about 1,000 ft. distant, by means of aWorthington four-stage centrifugal pump, direct connected with a 100-h.p. rnotor placed just south of the factory, and 1,500 ft. from the nozzle This plant handles the m...