 The ores, though uniformly of low grade, are very profitable. Some of the ores at the surface were below the average tenor, while other surface ores were two or three times as rich as the average. The valuable minerals extend downward as far as exploration...  The Enrichment of Ore Deposits - Page 329by William Harvey Emmons - 1917 - 530 pagesFull view - About this book
 | Ulysses Sherman Grant, Daniel F. Higgins - Glaciers - 1913 - 800 pages
...schist—quartz, orthoclase, hornblende, biotite, garnet, tremolite, actinolite, titanite, and graphite. 2 The ores, though uniformly of low grade, are very...as exploration has gone and are fairly uniform to 1,000 feet or more below the surface. In general, according to SF Emmons, 3 enrichment by surface leaching... | |
 | Medicine - 1913 - 602 pages
...Hills, SD—The principal minerals are quartz, dolomite, calcite, pyrite, arsenopyrite, and gold * * *. Some of the ores at the surface were below the average tenor, while other surface-ores were two or three times as rich as the average * * *. In general, according to SF Emmons,... | |
 | Anthropology - 1913 - 594 pages
...Hills, SD—The principal minerals are quartz, dolomite, calcite, pyrite, arsenopyrite, and gold * * ». Some of the ores at the surface were below the average tenor, while other surface-ores were two or three times as rich as the average * * *. In general, according to SF Emmons,... | |
 | William Harvey Emmons - Geology, Economic - 1918 - 642 pages
...cut by many dikes of porphyry but apparently have not been much affected by them. The ores, though of low grade, are very profitable. Some of the ores at the surface were below the average in tenor, but other surface ores were two or three times as rich as the average. The valuable minerals... | |
 | William Harvey Emmons - Geology, Economic - 1922 - 544 pages
...many dikes of porphyry but apparently have not been much affected by them. The ores are of low grade. The valuable minerals extend downward as far as exploration has gone and are fairly uniform to depths 2,000 feet or more below t IK- surface. In general enrichment by surface leaching is subordinate. Near... | |
 | William Harvey Emmons - Geology, Economic - 1922 - 544 pages
...many dikes of porphyry but apparently have not been much affected by them. The ores are of low grade. The valuable minerals extend downward as far as exploration has gone and are fairly uniform to depths 2,000 feet or more below the surface. In general enrichment by surface leaching is subordinate. Near... | |
 | Mineral industries - 1910 - 1086 pages
...w *'-J r (1904). » » Devereux, WB, Tmns., x., 469 (1881-82). 71 Irving, JD, loc. cit,, p. 90. ». very profitable. Some of the ores at the surface were below the average tenor, while other surface-ores were two or three times as rich as the average. The values extend downward as far as exploration... | |
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