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It is shown that factors associated with conditions whIch are thermodynamically favourable for the formation of CuS04 in roasting lead to high copper recoveries on leaching. One of these factors is the ratio of the air to solids used for roasting. This can be varied widely without loss of temperature control in the sulphating roasting of many Australian copper concentrates.Thus, the prediction of the air to solids ratio corresponding to a maximum p(SO3) value, for a given concentrate and temperature, is of importance in fluidized bed roasting, since this could be associated with the formation of a maximum quantity of CuS04. Calculations are presented which predict this air to solids ratio, not only for a given concentrate composition, temperature, and pressure, but also for air which is enriched with sulphur dioxide or oxygen.

Jan 1, 1968

By Olli Haavisto, Juha Timperi

"Accurate on-line assays of mineral slurries are the basis for effective operation of flotation circuits. Typically the elemental content measurements are obtained by an X-ray fluorescence (XRF) analyzer, which samples the process lines and performs the analysis concurrently line-by-line. For a more frequent measurement of each slurry line the XRF measurements can be complemented with reflectance spectrum information. In reflectance spectroscopy the absorbance properties of the slurry in the visible and near-infrared wavelength range are analyzed. The advantage of reflectance spectroscopy is that measurements can be obtained quickly and simultaneously from several slurry lines. However, since the shape of the spectrum is only indirectly affected by the slurry elemental contents, frequent calibration of the measurement against the XRF analyzer is necessary. This study elaborates the combination of reflectance spectrum analysis with XRF. Results of laboratory tests for different slurries are presented and the operation of the system in a copper-zinc flotation plant is demonstrated.IntroductionElemental analysis of mineral flotation slurries is the most important factor in evaluating the performance of concentration processes. Timely on-line assays are also used as the basis for controlling the circuits and ensuring that the grade and recovery targets are reached. X-ray fluorescence (XRF) is the dominant technology in on-line elemental slurry analysis, and typically centralized XRF analyzers are used. The advantage of a centralized analyzer is that one measurement probe can be used to acquire the data from several slurry lines. This reduces the overall operating cost of the system when compared to distributed analyzer system design with several measurement probes requiring maintenance and spare parts. Slurry samplers are installed in the interesting process flows and representative sample flows are brought to the analyzer, where the slurry is further sampled and measured consecutively by the XRF analyzer. Due to the centralized structure of the analyzers and consecutively measurement of the sampling lines the sampling interval per slurry line can be relatively long. In larger concentration plants with several sampling lines a typical assay interval is in the range of 10-20 minutes."

Jan 1, 2016

By Y. K. Wong

This paper describes in detail various problems concerning the construction of a pile-raft foundation supporting a 42-storey tower block. The subsurface generally consists of highly weathered sedimentary rock. A comprehensive instrumentation program is implemented to monitor the behaviour of the foundation system throughout the construction period of the superstructure. Instrumentation observations are highlighted in the second half of the paper.

Jan 1, 2010

Mineralogical analysis of a nickeliferous laterite from the Rockhampton region shows that the nickel is largely associated with the manganese wad and opaline silica. The laterite also contains an appreciable chromite content (about 12 per cent Cr2O,) although this tends to be poorly liberated.Leaching with hydrochloric or sulphuric acid, at atmospheric pressure at the boiling point is non-selective with respect to iron dissolution.The degree of dissolution increases as the acid concentration and retention time are increased; cobalt dissolution requires less aggressive conditions than does the dissolution of an equivalent amount of nickel.Leaching with sulphuric acid at elevated temperatures and pressures leads to a minimum amount of iron dissolution, is rapid, and requires a reduced acid addition rate. Nickel and cobalt recovery from the clarified leachate would be simplified because of the leach selectivity.Pressure leaching appears to be the most practical route for treating the Rockhampton laterite. The economics of processing would be made more attractive by the recovery of a chromium concentrate from the leach residue. This would typically contain about 45 per cent Cr2O, and could be used as a source of chromium chemicals.

Jan 1, 1986

The usual metallurgical, engineering and administrative activities associated with the handling and smelting of ores, and the subsequent handling and treatment of the products of smelting, present also problems of hygiene that engage the earnest attention of executives in all well-managed concerns.Again, associated with the employment of any considerable number of men, there is always present the problem of accident prevention.INDUSTRIAL HYGIENE.In the earliest records of lead min.ing and smelting there are references to the injurious effects of lead oh the health of the employees, and, with the advancement of medical science, lead poisoning has been the subject of many works by various authorities in many countries.Moreover, in practically every civilised country, there are laws governing the conduct of the lead industry, and in most cases these laws stipulate that employees shall receive compensation for disability caused by lead poisoning.This provision gives the problem an economic aspect. Apart from the legal and the economic aspects, however, there is the humanitarian aspect, which implies that the...

Jan 1, 1937

The rock mass classification systems were developed for different functions, including support selection, excavation method selection and the determination of rock mass engineering properties for excavation design, among others. This explains in part why we have several rock mass classification systems. It is often cautioned that the rock mass classifications are to be used for preliminary excavation support design, but this caution is now often overlooked and detail/final support design based on the rock mass classification systems. This paper advocates differentiating between rock mass classification for pre-excavation support planning and rock mass classification for at-face excavation performance assessment. It is concluded that most at-face excavation performance problems are attributable to confusing the virgin rock mass rating with the rock mass rating on exposure during excavation, and that this observation is independent of the method of excavation. Procedures are then presented for virgin rock mass rating and for at-face rock mass rating/assessment during excavation.

May 1, 2009

By F. T. Cawood, M. A. Jooste

This paper describes the survey monitoring processes at Venetia, which are discussed under visual inspections, ad hoc investigations, system monitoring and slope stability radar monitoring. This is followed by a description of the main survey monitoring methods. The next section briefly states typical problems, i.e. the atmospheric corrections required to adjust total station distances, maintenance of the system and management of the monitoring process. The paper ends with some important lessons that could be applied to similar monitoring programmes. These lessons are firstly, communication is most important, process a vital part of the system, a champion must take responsibility for the programme and system planning ensures that the monitoring results are needs driven.

Jan 1, 2006

Research into the mechanisation of ore winning from the very narrow reefs characteristic of South African gold mines has been conducted from as early as 1964 through the Chamber of Mines Research Organisation (COMRO) but with limited success. However, the Council for Scientific and Industrial Research (CSIR) has recently re-evaluated the potential for the mechanisation for the narrow tabular gold mines. It has been determined that there are approximately 22 000 tonnes of gold left in-situ in channel widths of less than 500 mm in thickness. The extraction of ore from such reefs requires a complete paradigm shift in that the current mining cycle (drilling, blasting, cleaning and supporting) is not feasible since such a stoping width would not allow the workers entry into the stope. Consequently, a non-entry form of mining is required. With this target in mind CSIR has invested in a project called the Nederburg Miner which seeks to identify new technologies for drilling, rock breaking, cleaning, and materials handling, the application of which will enable non-entry mining of very narrow ore bodies. The intention is to develop a fully automated system that will not require human involvement at the stope face. The outcomes of research into this proposed system will not only extend the life of South African gold mines but will also enhance South Africa's reputation for excellence in mining research. This paper presents the new technologies under consideration and potential methods for their application into an integrated non-entry mining system.

Jan 1, 2008

By Alan D. Fisher

Amtrak made a decision to replace an aging bascule bridge with a vertical lift bridge for their crossing of the Thames River in New London, Connecticut. The new lift bridge occupies the same alignment and shares the same foundations as the bascule span. During construction the deep foundation caisson supporting the bascule span settled and tilted. Investigation into possible reasons revealed interesting historical facts, both of the construction of the innovative open well caisson foundations and of the state-of-the-art in tremie concrete placing methods in use at the turn of the century. This paper describes both of these topics.

Jan 1, 2008

By R. Barbaroux, B. Dubreuil, D. Lemieux, K. Nasrallah, G. Garcia Curiel

"As conventional, base or precious metal ores are being depleted worldwide, the mining industry is being faced with an increasing exploitation of arsenical sulfidic ores. Enargite is a common example. The downstream processing of these ores poses several problems ranging from high smelter penalties to finding economical and environmentally acceptable means of disposing of the arsenic. Several hydrometallurgical processes have been proposed for extracting arsenic from enargite concentrates, notably using alkaline sulphide leaching (ASL). However, few alternatives exist for removing the arsenic from solution and stabilizing it in an approach that is both economical and environmentally acceptable.Dundee Sustainable Technologies (“DST”) has developed a technology for the sequestration of arsenic by vitrification. Originally optimized to cost-effectively stabilize arsenic trioxide (As2O3), DST has shown that vitrification could be successfully extended to the stabilization of other arsenical products, such as calcium arsenate (Ca3(AsO4)2) and sodium arsenate (Na3AsO4). In this paper, the vitrification of arsenic in the context of an enargite leaching was newly explored and demonstrated successfully.Two processing routes are being proposed by DST for the removal of arsenic from enargite concentrates and their stabilization by vitrification. In one route, arsenic is extracted by ASL and is then precipitated under atmospheric conditions and with minimal use of reagents and time. The resulting precipitate is an unstable hydrated ferric arsenate (FeAsO4•2H2O) that is then vitrified in a non-dilutive method, significantly increasing the stability of arsenic and meeting the TCLP guideline. Unlike is required for scorodite, stabilization was successfully achieved without concern for the crystallinity of the precipitate."

Jan 1, 2017

By D Gelling

Mineral sands dry plants consist of a large number of repetitive unit operations with significant transport delays, in the form of stream pipes, conveyors and elevators. As part of the P255 mineral sands sponsorship and using the JKMRC developed conductor/non-conductor (CNC) gauges, control loops have been implemented at the multi-duty dry plant of Cable Sands Limited at Bunbury. This paper describes the loops for kV control on a rougher high tension roll machines (HTR). The options available are product grade control and ratio control using the JKMRC CNC gauges, which measure the percent conductors in a stream. The purpose of control is to stabilise the circuit operation against disturbances such as atmospheric and feed disturbances.

Jan 1, 2001

Ore from the Hill 50 Gold Mine, consists essentially of pyrrhotite, with minor amounts of pyrite, chalcopyrite, galena and gold, replacing "jaspilite." The gold is associated with the sulphides as shotty particles. About 8 per cent. of the particles are less than '0.010'mm.The Hill 50 Gold Mine, at Boogardie in the Murchison goldfield, about 300 miles north-west of Kalgoorlie, was first operated in 1898. From 1898 to 1917 it yielded 20,000 short tons of ore for a recovery of 6,225' fine oz. gold, equivalent to a recovery grade of 6.22 dwt. gold per ton.The present company since the beginning of its operations in September 1936 to June 30, 1954, produced 811,081 short tons of ore for a recovery of 242,554 fine oz. of gold, equivalent to a recovery grade of 5.98 dwt. gold per ton.The grade of ore (recovery grade) has shown a remarkable variation with depth. From the 120 ft. Ievel to the 300 ft. level, it averaged about 7.5 dwt. Au per ton. Below the 300 ft. level it declined, and from 300 ft. to 400 ft. averaged 4.9 dwt. per ton, falling further with increasing depth to about 4.5 dwt. per ton at the '600 ft. level.On the 820 ft. level the grade improved sharply to about 14 dwt: per ton, and this grade has persisted down to and on the 1060 ft. level.The orebody has been described by Finucane (1953) as a series of lenses of finely banded jaspilite conformably enclosed by greenstones. The jaspilite is tightly folded and faulted and intruded by dykes of felspar porpnyry.Mineralization is practically restricted to the jaspilite.

Jan 1, 1955

By Yin Zongze

The pile foundation of Sutong bridge pylons is an extra large pile foundation. The length of piles is 115m, and the diameter of the piles is 2.5-2.8m. Since the traditional design method may not determine the settlement and capacity reasonably for such a large pile foundation, the finite element method is used to study stress and deformation of the foundation. The interface element is set to simulate the possible slide between piles and soil layers. The hyperbolic model is taken for soils. Parameters are determined from triaxial test first, and then modified by back analysis on basis of in-situ loading test. The computation results show that the axial force of piles changes with the location of the pile. Outer piles support greater axial force and also friction. The settlement will not be greater than 26cm. The stress and deformation of the pile cap, the abutment, are obtained too. The whole foundation is safe.

Jan 1, 2006

By C. R. Copeland

Water sprays are a common method used to reduce particulate matter (PM) emissions. Various factors such as wettability, surface area coverage, fine particle engulfment rates, interparticle adhesion forces, suppressant penetration and suppressant longevity have all been suggested as critical factors in achieving effective PM control. However, it has not been established which of these factors are the most important. Experimental work indicated that suppressant penetration is the most critical of these factors. The length of time after application that suppressants were effective was also improved by using hygroscopic reagents that retained moisture to prevent evaporation. Maximizing suppressant penetration and improving suppressant longevity led to an average 86% reduction in PM10 concentrations in laboratory dust tower tests.

Jan 1, 2008

The oxidation of ferrous sulphate to ferric sulphate with air and oxygen in a gas lift percolator was investigated with initial Fe2+ concentrations in the range 0·01 M to 1·0 M,temperatures in the range 20-80°C, and pH in the range oto 2.The rate of formation of Fe3+ was found to be well described by the rate expressionEquation 1and a consistent mechanism is proposed.The presence of Cu2+ was found to cause an increased rate of oxidation, the effect being greater with Cu2+ concentrations increasing in the range 0·001 M - 0·01 M in 0·2 M Fe2+. The effect of other solutes containing Ni, Zn, Mn, Co, Hg, Cl, Mo, NH4, As, Cr, or Na at a concentration of 0·001 M in 0·2 M Fe2+ was negligible.

Jan 1, 1972

By Murat Erdemoğlu, Turan Uysal, Thierno Saidou Barry, Mustafa Birinci

The rapid development of the global alumina and aluminum industry is straight coupled with the demands and the needs of these materials. Nowadays, the only well-known accessible resources to produce alumina and aluminum are bauxite ores. But bauxite ores are limited, and the remaining exploitable reserves do not have high contents in alumina. In countries where there is little or no bauxite reserves or where the recovery of existing bauxite ores to produce alumina with the Bayer process are not economic, alternative resources for alumina have been explored. The most attractive resources for replacing bauxites are aluminosilicate clay minerals and coal fly ash. The important processes developed for the recovery of alumina from these sources are acid leaching and alkaline leaching processes. The acid leaching is known as the most efficient in which thermal and mechanical activation are included for improving the performance of the process. The objective of this review is to give a comprehensive insight on the production of the alumina from thermally or mechanically activated clays and coal fly ash by hydrochloric, sulfuric, and nitric acid leaching processes.

THE Phillips River gold and 'copper field is situated on the south coast of Western Australia, about 200 miles east of Albany, 180 miles west of Esperance, and: 250 miles south of Southern Cross, forming the southern extremity of what Mr. H. P. Woodward classes as the fourth belt of Pre-Cambrian rocks, and the first auriferous belt, whicf extends northward through Southern Cross, Mount Magnet, and Cue. The field may be considered the premier copper producer of the State. The first mineral discoveries were made about 1892; when gold, copper, and iron pyrites were found; but, owing to the isolation of the district and the scarcity of water, both in the locality and on the route thereto, little work was done for some years. In1899, however, payable gold reefs were opened up, and the district began to attract attention.The southern portion of the district is composed of limestone and sandstone rocks, forming the coastal series, and is for the most part flat, broken only by a few low hills and ridges, except to the west, where Cape Barren and Eyre's Range stand out...

Jan 1, 1917

The large increase in secondary industries in this country, during the war and post war periods, has caused a shortage of capacity for the production of merchant bar.To overcome this shortage, an expansion of rolling mill facilities has been undertaken by the Broken Hill Pty. Co. Ltd. A small, but modern, merchant mill has been erected at Kwinana in Western Australia and a strip and skelp mill is under construction at Newcastle. The latter mill will roll strip and skelp at present being rolled by the Newcastle 10 in. Merchant Mill, enahling this mill to concentrate on merchant bar production.The Kwinana mill was installed to supply the Western Australian market. This state has a small population (approximately 658,000) and is not at present highly industrialised. It was necessary, therefore, to design a mill which would be capable of producing a wide diversity of sections and could be expanded as the demand increased. To begin with capital expenditure had to be kept within reasonable bounds. The design work for this mill, with the exception of a few specialised items of equipment, was carried out at Newcastle.All design work for the Newcastle mill was carried out by the lVIorgan Construction Co. of America. Although initially intended for rolling flat. products, the designers were asked to make the mill as flexible as possible, so that should the market for flat products decrease, this mill with additional equipment could undertake the rolling of medium sized sections.

Jan 1, 1957

By Tim O’Neil

Question: Looking forward, do we face a future in which energy markets, energy policy and energy conflicts threaten to preoccupy, if not dominate, our concerns over economic growth, national security and domestic tranquility? The answer is, we may indeed face such a future. Question: What oil resource is comparable in size to the reserves of Saudi Arabia and presents a tremendous opportunity? The answer, the oil sands in Alberta, Canada. Question: What is the largest mineral staking rush in North American history, still under way? It has so far led to the development of two large mines. The answer is the Point Lake diamond strike in Canada’s Northwest Territories. It led to the development of the Ekati and Diavik mines.

Jan 1, 2004

A general outline of the significant features in the quality and manufacture of the more common refractories is given. Where possible, linkage between quality development and control and service applicationhas been shown and explained. INTRODUCTIONThe refractory industry is no stranger to change. New processes and revision of old processes in other industries are the harbinger of new and revised products in refractories.Few of the changes are dramatic; generally they are evolutionary rather than revolutionary. New developments are additional to, and inclusive of, established practice.Therefore in this paper it is necessary to repeat much of what is already known in order to show the development taking place.FIRECLAY REFRACTORIESGeneral technology Fireclay refractories are the most common, the most varied and the most versatile of all refractories. Virtually any composition of silica and alumina up to the composition of kaolin is possible. For purposes of comparison they may be classified in the Continental fashion in accordance with chemical composition or in the American way according to "duty". That the two methods are equivalent is shown by an inspection of the alumina-silica diagram of Bbwen and Greig (1924). 'Fireclay refractories are composed of a glassy and a crystalline component derived from the chemical and physical nature of the raw materials used in their manufacture.

Jan 1, 1961