The methods employed in dressing the tin ore up to the required percentage of purity depend mainly on the type of ore crushed. These may be briefly divided into two distinct classes—viz., a free milling ore and a complex milling ore. In the former the ore is practically free from the common metallic sulphides, such … Read more
The purpose of this paper is to discuss the relative merits of the large 3 1/8-in. machine and the small mining drill 2¼-in. tappet machine in driving development-headings; and although the data here presented were obtained from cross-cut headings alone, experience has shown that the results are equally true in drifting, raising and winzing. Recently … Read more
Here is a short account of the treatment of the base bullion for the recovery of lead, silver, and gold, and for the treatment of by-products. Appended is a short description of the chief facilities of plant which have been adopted to overcome the main difficulties in the refining of lead. The difficulty of obtaining fair samples … Read more
The ore consisted of quartz, in which, above the 250-ft. level, the iron-minerals were largely oxidized and some free gold was visible; below that level few traces of oxidation occurred, and pyrite constituted the principal mineralizer in the quartz, together with occasional pockets of galena and a few eccentric specks of covellite. The 20-stamp mill … Read more
We have already devoted two previous memoirs to this question. In the first we collated and discussed the existing literature on the subject; in the second, we described the crystalline forms obtained by the reduction, at different temperatures, of ferrous chloride by hydrogen or by zinc-vapor. The conclusion from these researches was that the three … Read more
In the zeal for opening up new ore-bodies, or for extracting the ore from attractive bodies already opened up, we very often lose sight of the fact, that, after all, the operation of a mine is a business proposition, pure and simple, and, for the best working-results, should be treated upon a strict business basis. … Read more
Although the bromo-cyanide or Diehl process for the extraction of gold from its ores is used on several of the Kalgoorlie mines, very little information has been published on the original process, and no details are available from the various mines now using it. The following description of the process as carried on at the … Read more
The working of gold alluvial deposits by dredging has from all times been a popular form of mining, not only from the simplicity of its operations, but also, in its more primitive stages, from the possibility of carrying it on without large capital, without skilled labour, expensive plant, long terms of preparatory work, or, in fact, any … Read more