 ... 10 to 25 per cent, of the amount quarried is salable as slate. The remaining 75 to 90 per cent, is of no service to the slate miner. It is sent to the dump heap and is a continual source of trouble and expense.  Congressional Serial Set - Seite 391904Vollansicht - Über dieses Buch
 | 1906 - 1058 Seiten
...that only about 10 to 25 per cent of the amount quarried is salable as slate. The remaining 75 to 90 per cent is of no service to the slate miner. It is...material, however, as can be seen from the analyses (juoted be-low, is often admirably adapted for use in connection with limestone in a Portland cement... | |
 | 1904 - 768 Seiten
...that only about 10 to 25 per cent of the amount quarried is salable as slate. The remaining 75 to 90 per cent is of no service to the slate miner. It is...obtained very cheaply by the cement manufacturer. Cnrnponillon nf American roofing slate*. VALUE OF DEPOSITS OF CEMENT MATERIALS. The determination of... | |
 | Edwin Clarence Eckel - 1904 - 148 Seiten
...that only about 10 to 25 per cent. of the amount quarried is salable as slate. The remaining 75 to 90 per cent. is of no service to the slate miner. It...admirable for use, in connection with limestone, in a Portland cement mixture. As it is a waste product, it could be obtained very cheaply by the cement... | |
 | George Ferdinand Becker - 1904 - 732 Seiten
...that 011)3' about 10 to 25 per cent of the amount quarried is salable as slate. The remaining 75 to 90 per cent is of no service to the slate miner. It is...and" expense. This very material, however, as can lie seen from the analyses ({noted below, is often admirable for use, in connection with limestone,... | |
 | Edwin Clarence Eckel - 1905 - 800 Seiten
...quarried is salable as slate. The remaining 75 to 90 per cent is of no service to the slate-miner. It is sent to the dump heap, and is a continual source...obtained very cheaply by the cement manufacturer. Geographic distribution of slates. — The principal areas in the United States in which roofing slate... | |
 | 1905 - 602 Seiten
...twenty-five per cent of the amount quarried is salable as slate. The remaining seventy-five to ninety per cent is of no service to the slate miner. It is...admirable for use. in connection with limestone, in a Portland cement mixture. AS it is a waste product, it could be obtained very cheaply by the cement... | |
 | Geological Survey (U.S.) - 1905 - 462 Seiten
...only ¡i bo tit I« to 25 per cent of the amount quarried is salable as slate. The remaining 75 to 90 per cent is of no service- to the slate miner. It...and" expense. This very material, however, as can he seen from the analyses quoted below, is often admirable, for use, in connection with limestone,... | |
 | Heinrich Ries - 1906 - 690 Seiten
...that only about 10 to 25 per cent, of the amount quarried is salable as slate. The remaining 75 to 90 per cent, is of no service to the slate miner. It...admirable for use, in connection with limestone, in a Portland cement mixture. As it is a waste product it could be obtained very cheaply by the cement manufacturer.... | |
 | Geological Survey (U.S.) - 1906 - 226 Seiten
...that only about 10 to 25 per cent of the amount quarried is salable as slate. The remaining 75 to 90 per cent is of no service to the slate miner. It is...can be seen from the analyses quoted below, is often admirably adapted for use in connection with limestone in a Portland cement mixture. As it is a waste... | |
 | Thomas Nelson Dale - 1906 - 220 Seiten
...that only about 10 to 25 per cent of the amount quarried is salable as slate. The remaining 75 to 90 per cent is of no service to the slate miner. It is...dump heap, and is a continual source of trouble and excuse. This very material, however, as can be seen from the analyses quoted below, is often admirably... | |
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