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Practical gold-mining; a comprehensive treatise on the origin and occurrence of gold-bearing gravels, rocks, and ores, and the methods by which the gold is extracted - Softcover
Synopsis
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. 1889 Excerpt: ...a western underlie, although there are many rich reefs that dip east. Nicholas also mentions that the saddle-formed reefs so characteristic of the master lodes of the Sandhurst gold-field are not confined to that field. Respecting the shoot of gold, Nicholas got particulars of the dip of 57 "pay chimneys" (as they are called in California) or shoots, 25 of which dipped to the north, 28 to the south, and 4 were vertical; the prevailing angle of the north and south shoots was between 250 and 50 There may be some difficulty in defining the dip of the shoot in reefs that contain fine gold evenly distributed; but in all cases, if a longitudinal or working section were kept, the course of the vein worked out would show the dip of the shoot of quartz, with which the shoot of gold usually conforms. In Nicholas's own experience, he has found that the shoot of quartz is invariably at right angles to the lines of striation on the walls or laminations of reefs, or to the heads or joints in the bounding rocks In California, it has been observed that the pay-chimneys run with the lines of striation. That the dip of the shoot of quartz or gold should be known, is a matter of the first importance in the working of all mines, and especially to adjoining mines. Nicholas gathered the widths of 286 Victorian reefs. Of these, 237 were in Lower Silurian rocks, and 49 in Upper Silurian. He divided these widths into three classes, viz. (1) under 5 ft, (2) over 5 ft and under 10 ft, (3) over 10 ft. Of the 237 reefs in the Lower Silurian, 168 were under 5 ft, and averaged 2 ft. 5 in.; 45 were over 5 ft, and averaged 6 ft. 8 in.; and 24 were over 10 ft, and averaged 29 ft. Of the 49 reefs in the Upper Silurian, 44 were under 5 ft., and averaged 2 ft. 1 in.; 1 was over 5 ft....
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