Bulletin Volume 17-21

Bulletin Volume 17-21

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1904 edition. Excerpt: ...by the official figures, appears to have been obtained from the workings t"1w embraced by the Grant's Hill Lease 122l. (vide the plan of the Nullagine Conglomerate Gold Mines, Plate II.) The returns from this demonstrate that 3,433 tons of ore yielded l,780-24ozs. of gold, Of at the rate of 52oz. per ton. The auriferous conglomerate, which has already been shown to be of sedimentary origin, is made up of rounded and subangular fragments of the strata identical in character with that forming the underlying Mosquito Creek Series. Certain portions of the conglomerate are marked by the presence of abundant iron pyrites, ud its oxidation products 5802, 5806. It is, however, in the oiidised zone of the conglomerate that any mining has, up to the present, been carried on. In 1897, samples of the auriferous conglomerate were examined in the Survey Laboratory and have been thus described: -"A specimen 190 typical of the finer-grained portions of the rock in its upper decomposed portions. It consists of subangular fragments of quartz, ironstone and shale, cemented together by ironstained kaolin, containing numerous cuboidal cavities at one time filled by pyrites crystals, as shown by the numerous pseudo morphs of limonite contained by them It assays loz. 6dwts. of gold A similar but less ferruginous variety, 191, showed no cavities vacated by pyrites, and is much coarser in grain, some of the fragments of quartz being '3 inches iu length; it assays 2ozs. ldwt. of gold per ton." Another variety 192 made up of large pieces of felstone, with smaller fragments of quartz embedded in a kaolinic matrix, assayed l0dwts. of fine gold and 5ozs. 4dwts. of coarse gold per ton. A noteworthy feature in the conglomerate is the occurrence of pyrites...
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Product details

  • Paperback | 138 pages
  • 189 x 246 x 8mm | 259g
  • United States
  • English
  • black & white illustrations
  • 1236924142
  • 9781236924148