Download or read book Investigation of Refractory Gold Ores Suggestions for Future Work on Refractory Gold Ores of the Barberton Goldfield written by and published by . This book was released on 1966 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As a result of both the writer's visit to the Kalgoorlie goldfield in Western Australia and the testwork conducted in the Government Metallurgical Laboratory on refractory gold ores, several recommendations have been made in this report for future work on the refractory gold ores from the Barberton goldfield. The conclusion has been drawn that it is unlikely that a treatment method, for oxidation of auriferous sulphide concentrates, economically superior to roasting will be developed. Consequently, eight recommendations, oriented towards the possibility of increasing the income of the Barberton mines, have been made. These recommendations, which aim at reducing the gold content of all waste material discarded from the reduction works and developing the recovery of saleable material other than gold, are as follows: 1. That cyanidation of the flotation concentrate be investigated with special reference to reducing the gold value of the calcine cyanidation residue and to the recovery of silver. 2. That the method of roasting be assessed with a view to improving, if warranted, control over the chemical reactions involved during roasting. 3. That testwork be continued on the recovery of gold from the calcine cyanidation residue. 4. That methods for reducing the gold content of the flotation tailings be investigated. 5. That the recovery of arsenic and gold from the flue gases be investigated. 6. That the recovery of elemental sulphur, or alternatively, the manufacture of sulphuric acid be investigated. 7. That the recovery of gold from the carbonaceous scum from the Sheba mine be investigated. 8. That the pressure oxidation of the auriferous sulphide concentrate be investigated.
Download or read book Investigations on Refractory Gold Ores Visit to the Barberton Goldfields 27th 30th May 1964 written by and published by . This book was released on 1964 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report discusses the visit paid to the Barberton Goldfields over the period 27th-30th May 1964. The following recommendations, arising out of the visit, are made: (i) the question of metallurgical balances should be raised with the mining companies, (ii) work should be carried out, using the hot-stage microscope technique, to investigate the chemistry of the roasting process.
Download or read book Refractory Gold Ores Visit to the Barberton Mines 15th to 18th February 1966 written by and published by . This book was released on 1966 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The visit was undertaken to discuss proposals for future work on this project with members of the Barberton Mining Association. In addition, data were sought to bring the records of the Government Metallurgical Laboratory (GML) up to date, and samples were taken. The following conclusions, given in order of priority, were drawn from discussions with the above Association. (1) Assistance can best be given to the mines by investigating the operation of the Edwards roasters. (2) Although the mines are investigating the flotation operation themselves, mineralogical examination of the flotation tailings, to determine the distribution of the gold, is desired. (3) Pre-cyanidation of the flotation concentrate is to be investigated. (4) The recovery of arsenic and gold from the flue gases and dusts is to be investigated. (5) The possibility of manufacturing sulphuric acid is to be assessed. (6) Short-term testwork on the various problems raised (mainly by Mr Proudfoot and Mr Harris) will be undertaken.
Download or read book Investigation of Refractory Gold Ores Examination of the Ore from Golden Hill Mine Barberton District written by and published by . This book was released on 1965 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ore from the Golden Hill Mine is a refractory ore in that less than 8 per cent of the gold can be extracted by conventional cyanidation. Mineralogical examination has shown that over 99 per cent of the gold is included in the sulphide minerals, in particular in the pyrite. The average particle size of the gold is small, being 7 by 5 microns. Chemical tests have shown that there are two causes for the refractoriness of this ore: (1) Lock-up of the gold in the sulphidic minerals. (2) Precipitation of the gold from solution by the carbon present (0.6 per cent) in the ore. Good extractions (96 per cent) of the gold could be obtained only after roasting a sulphide concentrate of this ore before cyanidation. This is the only method of treating this ore that has been effective to date. The conditions and results of all tests conducted on this ore are given in an appendix.
Download or read book Investigation of Refractory Gold Ores Examination of the Ore from the New Consort Mine Barberton District written by and published by . This book was released on 1965 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ore from the New Consort Mine was submitted to the Laboratory as one of a number of refractory gold ores from the Barberton district. The results of conventional cyanidation tests and roasting tests carried out in the laboratory led to the conclusion that the sample of ore received is not in fact refractory, because extractions of approximately 96 per cent of the gold have consistently been obtained by conventional cyanidation techniques. This result is in agreement with the predictions of a mineralogical examination carried out in the Laboratory. The results obtained indicate further that roasting before cyanidation, which is the treatment at present given to the ore at New Consort, is, in fact, detrimental to gold extraction.
Download or read book Investigations on Refractory Gold Ores written by H. W. Mcculloch and published by . This book was released on 1963 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Refractory Gold Ores Report on a Visit to the Barberton Goldfield 30th May 1962 to 6th June 1962 written by and published by . This book was released on 1962 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Flotation Index written by Dow Chemical Company. Great Western Division and published by . This book was released on 1966 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mineralogy and Chemical Behaviour of Some Refractory Gold Ores from the Barberton Mountain Land written by and published by . This book was released on 1966 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: The object of this project was to investigate certain aspects of the problems relating to gold extraction that have forced many small mines in the Barberton Mountain Land, Eastern Transvaal, to close down, mainly because the unoxidized ores have not responded to the conventional methods of treatment. The results of a detailed mineralogical examination of ores from sixteen localities in the area are followed by a brief literature survey on the nature of refractory gold ores and their treatment. The ores considered include the present chief gold producers - those from the Agnes, Fairview, New Consort, and Sheba Mines. The following fifty five ore minerals are present, gold being associated with twenty five of them: Ankerite, native antimony, argentite, arsenopyrite, berthierite, metallic bismuth, bornite, bournonite, chalcocite, chalcopyrite, chloanthite-skutterudite (types 2 and 3), chromite, cobaltite, native copper, corynite, covellite, cubanite, electrum, enargite, famatinite, franklinite, galena, graphite, goethite, native gold, hematite, ilmenite, jamesonite, lepidocrocite, leucoxene, linnaeite, loellingite, magnetite, malachite, marcasite, maucherite, melnikovite-pyrite, millerite, molybdenite, neodigenite, niccolite, pentlandite, pyrite, pyrrhotite, safflorite, siderite, native silver, sphalerite, stibnite, tetradymite, tetrahedrite, (two types), trevorite, and ullmannite. The paragenesis of these minerals is discussed briefly. An attempt was made to correlate the mineralogical properties of some of the ores with their expected behaviour. Chemical processing tests carried out included conventional cyanidation, dilute leaching, cyanidation in the presence of kerosene, and cyanidation of roasted ores. The results obtained showed that, in general, the agreement between the predicted and the actual figures for gold extraction was reasonably good. Explanations are given for discrepancies between these values. The chief cause of the refractory nature of the gold ores from the Barberton Mountain land was found to be the locking of gold particles in sulphide minerals, mainly pyrite and arsenopyrite. Other important causes are the precipitating effect of carbonaceous material, the presence of pyrrhotite, and the presence of unusual alloys of gold, which exhibit a pinkish tinge in polished section and may be refractory to cyanide solutions. The results of preliminary investigations of this 'pink' gold by an electron microprobe are included. The best extraction results for most ores from the area are generally obtained by leaching roasted sulphide concentrate.
Download or read book Refractory Gold Ores written by P. A. Laxen and published by . This book was released on 1963 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Refractory Gold Ores Report on Information Obtained During a Visit to the Barberton Goldfields 23rd to 27th July 1962 written by and published by . This book was released on 1963 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Refractory Gold Ores Laboratory scale Tests on the Roasting of Ore from the Mount Morgan Mine written by and published by . This book was released on 1965 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The construction and the operation of the kiln is described. The effect of the temperature and the residence time in the kiln on the subsequent gold recovery, and on the arsenic, sulphur, and carbon contents of the product, have been investigated. Activation of the carbon, by roasting, yields low gold-extraction figures, owing to the precipitation of the gold onto the carbon. At high temperatures (ie, 730 degrees C), where the carbon is substantially burnt off, the gold extraction increases to a value of 74.5 per cent. The alloying or coating of the gold by lead compounds or other constituents in the ore during roasting is thought to be the cause of the limit to the maximum gold extraction figures obtained. Arsenic does not appear to have any effect on the extraction of gold from the ore. The pyrite surrounding the gold particles is decomposed and cracked during roasting, thus allowing penetration by the cyanide solution.
Download or read book A Mineralogical Investigation of Refractory Gold Ores and Their Beneficiation with Special Reference to Arsenical Ores written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A mineralogical investigation of the main causes of refractoriness of some metallurgically complex gold ores in South Africa is reported. It is shown that this refractoriness is related to the presence of submicroscopic gold, carbonaceous material, pyrrhotite, and base-metal sulphides. Gold ores can be classified according to their content of these components. Electron-microprobe analysis shows that gold occurs in arsenopyrite and pyrite, the gold contents of which can be up to 2700 g/t. The gold and arsenic contents of these minerals are closely correlated. Furthermore, within zoned arsenopyrite grains, the concentration of gold closely follows that of arsenic. Mossbauer spectroscopy carried out on samples of concentrate from the Barberton area indicates that the submicroscopic gold within the sulphides is in a non-metallic form. The mineralogical examination of beneficiation products is important, since it sheds light on some fundamental aspects of the behaviour of the ore and gangue components during milling and flotation. Such basic information will lead ultimately to a better understanding of the problems in the beneficiation of these ores. Investigations have shown that the overmilling of the auriferous arsenopyrite and the disseminated nature of the sulphide mineralization are the main problems during beneficiation.
Download or read book A Mineralogical Investigation of Refractory Gold Ores and Their Beneficiation written by and published by . This book was released on 1986 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A mineralogical investigation of the main causes of refractoriness of metallurgically complex gold ores in South Africa is reported. It is suggested that this refractoriness is related to the presence of submicroscopic gold, carbonaceous material, pyrrhotite, and base-metal sulphides. Means by which problems in the beneficiation of these ores can be overcome were also investigated, and some possible solutions to these problems are offered. A study of beneficiation products from the Fairview Mine showed that submicroscopic gold is associated mainly with arsenopyrite, the gold content of which can be up to 2700 g/t. During miling of the ore, the grains of arsenopyrite, which are smaller than 150 um and have a low resistance to attrition, are selectively broken down. The response of the ultrafine sulphide particles to flotation is relatively poor, and they are preferentially lost to the final tailings together with the gold they contain. It is suggested that the overgrinding of auriferous sulphides can be minimized by the removal of the coarse sulphides from the comminution circuit by flotation or gravity separation. At high rates of aeration in the scavenger and cleaner flotation cells, ultrafine gangue and pyrrhotite are selectively recovered. This material may be recirculated and build up in the flotation circuit, where it may have a detrimental effect on the flotation of the sulphides. Hence, if the amounts of these components can be minimized, the recovery of the gold and the sulphides in these refractory ores can be improved. Means by which this might be accomplished are suggested.
Download or read book Flotation Index written by and published by . This book was released on 1961 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Mineralogical Investigation of Refractory Gold Ores and Their Beneficiation written by Peter Michael Swash and published by . This book was released on 1986 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigations on the Treatment of Refractory Gold Ores from the Giant Reefs Mine written by and published by . This book was released on 1966 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Additional samples of ore from the Giant Reefs Mine were investigated in the light of previously reported results. Fine grinding and dilute leaching in the presence, and in the absence, of mill waters was carried out. It was found that the refractoriness of these ores is due to the chemical interference during cyanidation and that satisfactory results could be obtained by leaching at 5:1 liquid/solid ratio in the presence of mill water. As the mine was not in operation when samples were taken, no sample representing a 'mill head' could be obtained. Therefore each of the samples investigated was composed of rock chippings from one particular site. These samples differed from each other considerably in grade and composition. It was found impossible to assign a constant head value and behaviour to any of the samples because significant variations in gold content and chemical activity were observed in duplicate portions of each of the samples. This variability of properties made it impossible to determine exact conditions for maximum gold extraction for any of the samples. However, the above-mentioned leaching technique was found to give consistently high extractions on duplicate portions of each of the samples.
