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. 1919 Excerpt: ...section is then mined out in the same manner. Figure 3 is a section taken through one of the lenses, showing the sill and third floor. The ore was first cut by the prospecting crosscuts 1-4-C and 5-4-One prospect raise was then put up at the intersection of 1-4C and 5-4-C and another 60 ft. beyond it, oif 5-4-C, to ...
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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. 1919 Excerpt: ...section is then mined out in the same manner. Figure 3 is a section taken through one of the lenses, showing the sill and third floor. The ore was first cut by the prospecting crosscuts 1-4-C and 5-4-One prospect raise was then put up at the intersection of 1-4C and 5-4-C and another 60 ft. beyond it, oif 5-4-C, to determine the height of the orebody. As the first stage, the chute crosscuts are driven at right angles to 5 + at an average of 40 ft. center to center, starting at 1 + C. These are driven to the edge of the orebody and later serve as haulageways from the stopes. Two-compartment timbered raises are put up, off 5 + C at 20-ft. intervals, starting at No. 1 raise, to the top of the orebody. Usually every second raise is carried up to the level above, to permit timbers being lowered into the stope, and also so that waste can be introduced as filling after the pillars have been mined out. In the case of the orebody in Fit. 39 the ore lyins; to the east of 5-f-is only about 25 ft. wide, hence no crosscuts were driven off 5-j-on this side. In most cases the crosscuts in ore require timbering. This method contemplates mining only the ore from the first floor (8 ft. above the sill) to the top of the orebody at this period; the ore below will be mined at a later time. After the ore has been blocked out by raises and crosscuts, a single row of lead gangways sets is run at right angles to 5 + off the first floor of the chute compartment of each raise to the edge of the orebody. Every other row of gangway sets will be directly over, or at the side of, the top of the chute crosscuts. These sets, if over the crosscut, are taken out in the same manner as in square-set stoping--usually being drilled with a stoper machine. The row of lead sets not touching the chu...
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Add this copy of Mining Practices to cart. $40.03, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Santa Clarita, CA, UNITED STATES, published 2010 by Nabu Press.
