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By C. R. Tang

Due to the current lack of sufficient occupational hazards supervisory staff in China, an occupational hazards supervision regulatory framework is proposed, based on the cloud. Data on respirable dust, noise, heat, toxic and hazardous substances and protection facilities are uploaded to private cloud computing data and service centers to build an occupational hazards supervision system. This system promotes occupational hazards governance. Complex reports are generated. Through the establishment of an occupational hazard supervision data threshold, the dynamic regulation of occupational hazards is accomplished. The main characteristics of this approach are low cost, ease of expansion and maintenance, and strong performance.

Aug 1, 2013

By J. K. Afidenyo, J. Osei-Owusu

"The Obuasi Mine of AngloGold Ashanti Limited has been operating the world’s largest Biooxidation Plant at its Sulfide Treatment Plant (STP) in Ghana, using the Gencor Biox® technology since February 1994. The Biox® technology was preferred to other alternative methods of treating refractory sulfide ores such as roasting, pressure oxidation and nitric acid leaching due to among other reasons, its lower capital and operating costs, reduced technical risk, relatively benign environmental impact and its ease of operation and maintenance in a remote location.STP has since commissioning succeeded in operating this technology successfully but not without some operational problems. The Plant has seen a number of upgrades and modifications in its circuits which were motivated by cost, operational and throughput constraints.The objective of this paper is therefore to highlight the mine’s experience in the treatment of its complex carbonaceous refractory sulfide gold ores with emphasis on plant operations and improvements such as the Biox® reactors expansion, flotation concentrate upgrade project and neutralization circuit modifications. The Biox® Plant operating cost is also discussed.INTRODUCTIONThe Obuasi mine forms part of the AngloGold Ashanti Group of Gold Mines. It is located in the Adansi West District of the Republic of Ghana. The mine is primarily an underground operation, although some surface mining still takes place. Ore is processed by two main treatment plants: the Sulfide Treatment Plant (for underground ore) and the Tailings plant (for tailings reclamation operations). A third plant, the Oxide Plant, is used to batch-treat remnant opencast ore and stockpiles, of which there are adequate tonnages to keep the plant operational until 2008.Though reference is made in this paper to the Tailings and Oxide Treatment Plants, the main focus will be on the Sulfide Treatment Plant."

Jan 1, 2008

By J. A. Ruppert

The Bureau of Mines investigated methods of refining iron-contaminated zinc to marketable quality and developed a laboratory-scale process in which aluminum, added as a refining agent, reacted with the iron, forming solid Fe2Al which floated to the surface of the melt. Solids were separated by both filtration and centrifugation, using a unique type of "dipping" centrifuge devised during the work. Typical zinc recovery was 95 percent, and iron content of the metal was lowered from 0.37 to 0.02 percent.

Jan 1, 1967

Jan 1, 2002

By D. H. Desy

The Bureau of Mines has conducted research on the ignition of methane-air mixtures by sparks caused by frictional impact of aluminum alloys on rusted steel at typical coal mine fan speeds. The objectives were to establish the incendivity of aluminum alloys under these conditions, to investigate differences between aluminum alloys, and to evaluate substitute materials for the aluminum-steel combination. With a specially designed apparatus, three commercial aluminum casting alloys and a number of experimental aluminum alloys were tested for incendivity of the frictional impact against rusted steel in flammable methane-air mixtures. All aluminum alloys tested produced some ignitions. Of the experimental alloys, the harder alloys and those containing silicon tended to be more incendive than the others. With the normal experimental conditions, constructional steel, stainless steel, brass, and plastic did not cause ignition of methane-air mixtures in frictional impact against rusted steel. Some ignitions occurred with constructional steel at high speed in more flammable gas mixtures enriched with oxygen. From these findings, it is suggested that constructional material combinations other than the aluminum-steel combustion would minimize this inc endive hazard. A detailed description is given of previous research, and comparison is made with present results where appropriate.

Jan 1, 1975

By Doris M. Hyde

There were no significant changes in the mineral industries of the smaller Caribbean Islands during 1980. Imported petroleum requirements continued to erode economic gains that may have occurred in other sectors. Some relief may be forthcoming as more qualified Caribbean countries take advantage of Trinidad and Tobago's petroleum product financing program (see Trinidad and Tobago). There were no crude oil discoveries in these areas during 1980, although some geophysical testing around the British Virgin Islands and Antigua war underway. In March 1980, the Government of Antigua sold a 75% interest in the 16,000-barrel- per-day West Indies Oil Co. refinery to the Swiss Intermaritime Bank and Intermaritime Management Services for $6 million. The new refinery company is called the National Petroleum Co. Shutdown since 1976, it was originally planned for the refinery to reopen in 1980, but refurbishing has proved to be more extensive than anticipated. The reopening is now expected in 1981.

Jan 1, 1982

By Roberto Folchi, Hans Wallin

Having so many norms and technical content of legislation to deal with is a problem that an explo-sives engineer has to face, especially when working at an international level. Each country has its own norms and legislation, sometimes even each other region or state, as if the physics of explo-sions, rock, concrete, and masonry characteristics would change across the borders. Both norms and laws are frequently out of date, being mainly developed at the beginning of the previous century and adjusted, piece by piece, to a technical and political context that is constantly changing, with adjustment being frequently adopted in a hurry, due to a problem arising such as that of internation-al terrorism. Sometime also, norms are not harmonized with those they intend to amend, so required explanations and new adjustments lead to a vicious circle that increases confusion, complexity and depresses the explosive industry.

Jan 1, 2015

By J. Sliwinski, J. Oliveira

"The application of geometallurgy and corresponding sample selection can take on several formats within industry. Current practice can range from a strictly geostatistical approach to one in which geological and metallurgical parameters are used in combination to create a representative sample selection strategy. The stage of a project and the level of information available at the time of sampling influences the methodology used to create a representative sample.A geometallurgical study of Carpathian Gold’s Rovina Valley Project in Romania is used to demonstrate a sample selection strategy that integrates geological, mineralogical and metallurgical data to maximize the relevance of the geometallurgical unit definitions. This approach, practiced by Xstrata Process Support for its’ clients, ensures that the results of the metallurgical program can be interpreted in the context of these units.INTRODUCTIONGeometallurgy is a cross disciplinary approach in which metallurgical performance of an ore is linked to intrinsic geological and mineralogical characteristics. The objective of a geometallurgical study is to characterize the range of metallurgical performance of an orebody. This allows the geoscientist or metallurgist to create a robust flowsheet able to treat the full range in variability and to develop production strategies to maximize financial performance. The standard approach is to individually sample and test a series of ore types or geometallurgical units. Several different approaches are used in industry to define what constitutes geometallurgical units and how to sample them.One current methodology is the use of multivariate statistics. Geochemical data along with available geological data are used to define multiple variability domains (Williams, 2004; Walters, 2009). There are risks associated with this methodology since the extent of the data set itself may not support a purely statistical approach at the time that metallurgical units need to be defined. The assay suite collected by exploration programs is often limited to pay metals while metallurgical performance is often affected by ore gangue components. Furthermore, in many cases metallurgical scoping and pre-feasibility studies take place prior to the availability of extensive geochemical data sets. Purely statistical methods can produce multiple populations which require extensive sampling, testing and validation prior to consolidation into a reasonable number of composites for metallurgical testing. Methodologies are therefore required that allow representative sampling and testing of consolidated geometallurgical composites to occur at various phases throughout the development of a mining project."

Jan 1, 2013

By A. McLean, W. Q. Chen, W. Yan, M. Barati, Y. D. Yang

In order to maximally remove the harmful impurities phosphorus and reduce the loss of valuable elements from Si-based alloy for production of solar-grade silicon, thermodynamic properties of the Si-based alloy were studied. In this work a new model, the Molecular Interaction Volume Model (MIVM) derived from statistical thermodynamics, was successfully used in the Si-based and Si-Fe-based alloy. The calculation started from binary Si-Fe, Si-P and Fe-P systems, then the thermodynamic parameters of ternary systems could be derived based sub-binary systems. Using the activity coefficients of the elements in the Si-based alloys and the saturated vapor pressure of the pure substance of the components, mass fraction of P during vapor-liquid equilibrium can be calculated. The calculated thermodynamic parameters were compared with experimental data available in different publications, and it is found that the thermodynamic parameters calculated using MIVM model are in good agreement with the measured results. The calculated result shows that the mass fraction of phosphorus during vapor-liquid equilibrium of Si-Fe-P melt increases with the increasing phosphorus content and decreasing temperature. This is an important direction for experimental practice in vacuum or low-pressure EML refining of ferrosilicon for potential production of solar-grade silicon without significant vaporization loss of valuable element.

Jan 1, 2015

By W. W. Agey

This report summarizes results of bench-scale metallurgical studies by the Federal Bureau of Mines on three composite samples representative of the low-grade manganese ores purchased by the General Services Administration (GSA) and stockpiled at Deming, N. Mex., and Wenden, Ariz. Bench-scale flotation tests at the Salt Lake City Metallurgy Research Center showed that all three composites could be beneficiated by flotation to recover 88 to 90 percent of the manganese in concentrates that assayed from 38.5 to 39.0 percent Mn, 10 to 12 percent insoluble, 5 percent CaO, 3 to 5 percent Fe, and 1.3 to 1.7 percent combined Pb plus Zn plus Cu, Sintering studies indicated that specification-grade material could be made from these concentrates by sintering above 1,000° C, and adding either sodium or calcium chloride to the charge to insure removal of enough lead and zinc to meet the specifications.

Jan 1, 1962

By Luiz Alberto dos Santos

Neste trabalho foram usinados CDPs da liga com composição de 50,9 % at de Ni e, em seguida, as amostras foram envelhecidas em temperaturas entre 350-550 ºC, tensões aplicadas de 60 MPa e tempos de 45 e 180 minutos. Além disso, foram realizados também envelhecimento sem aplicação de carga nas mesmas condições de temperatura e tempos para comparação das propriedades, porém acrescentando uma amostra solubilizada a 850ºC durante 1 hora. Posteriormente as amostras foram caracterizadas por DSC para determinação das temperaturas de transformação de fases. Observa-se neste trabalho que o DSC de algumas amostras apresentou tanto no aquecimento quanto no resfriamento dois picos de transformação que pode estar relacionado ao aparecimento da fase R. Além disso, pode ter ocorrido a formação da fase Ni3Ti4, pois ligas com teores acima de 50,6 %at. de Ni são caracterizados pela formação de precipitados ricos em Ni, que pode acarreta na diminuição da concentração de Ni na matriz e aumento da temperatura de transformação. Este trabalho é importante, pois há poucos estudos relacionados com o efeito do envelhecimento sob carga nas propriedades de efeito de memória de forma e superelasticidade da liga NiTi.

Aug 16, 2017

By Charles Jackson Abrams

MINING is one of the major industries of the Rocky Mountain region and since the United States became involved in the present World War, all mines have been called upon by the Government for the maximum production of the strategic metals necessary. Operating under the most adverse conditions, such as priority requirements, slow delivery of necessary material and equipment, labor shortages, and freezing of all wages, which still permitted some industries to pay higher rates than were allowable in the mines, thereby drawing labor from the mines; and the United States Employment Service continually giving mine labor certificates of availability; these and many other problems made mine operation particularly difficult. Yet, in spite of these obstacles, the mining industry, either through its own resources or through Government subsidies in the form of loans or premium prices for strategic metal, have and still are making an all-out effort to meet Government demands. They, without question, have played a major role in assisting the war effort.

Jan 1, 1945

By J. S. Meyer

Although salmonid fishes (including Pacific salmon and trout) have only intermediate sensitivity to copper (Cu) for traditional toxicity endpoints (survival, growth, and reproduction) and thus do not ?drive? the freshwater Cu criteria (e.g., see species-sensitivity ranking in US EPA 2007), Cu concentrations as low as 1 to 2 µg/L have been reported to impair olfaction (the sense of smell) in salmonids in laboratory experiments using dilute fresh water (see references in Meyer and Adams 2010 and DeForest et al. 2011). Olfaction is crucial to predator avoidance, recognition of kin, and reproductive synchronization (Baldwin et al. 2003); and Cu is of general ecotoxicological concern because it can be present in acid/mine rock drainage, industrial and municipal effluents, agricultural runoff, and urban stormwater runoff (Meyer et al. 2007). Therefore, there is public concern that the current regulation of Cu in surface waters is not stringent enough to protect salmonid fishes against olfactory impairment (e.g., OSU 2007; Pearson 2007). Because the toxicity of metals to aquatic organisms is a function of water chemistry [e.g., acute toxicity of Cu generally decreases as pH, water hardness (Ca2+ + Mg2+), alkalinity, and dissolved organic carbon (DOC) concentrations increase; Meyer et al. 2007], hardness-based freshwater criteria for metals are lower at lower water hardness. The recently-developed biotic ligand model (BLM) explicitly takes into account all four of those water chemistry parameters and the concentrations of other major inorganic cations (Na+, K+) and anions (Cl-, SO42-) to predict the acute toxicity of cationic metals (e.g., Ag, Cd, Cu, Ni, Pb, Zn) to aquatic organisms; and the BLM has been adopted by the U.S. Environmental Protection Agency (US EPA) to calculate acute and chronic national freshwater criteria for Cu (US EPA 2007). Consistent with observations of Cu toxicity to aquatic organisms, BLM-based Cu criteria generally are lower at lower pH, water hardness, alkalinity, and DOC concentrations. Therefore, although threshold concentrations for olfactory impairment by Cu can be low in dilute fresh waters, the corresponding hardness-based and BLM-based Cu criteria for the same waters also tend to be low. This leads to a logical question: Are Cu criteria already protective against impairment of olfaction in salmonid fishes, thus obviating the need to decrease those criteria even lower to protect against adverse effects to this physiological/ecotoxicological endpoint? Herein, we demonstrate that in all studies conducted to date, the US EPA?s BLM-based freshwater Cu criteria would have been protective against olfactory impairment in salmonid fishes, but the US EPA?s hardness-based criteria would not always have been protective. This distinction is important because all 50 States in the USA still use hardness-based Cu criteria in their water quality standards, and only some of the States allow use of the BLM to calculate site-specific Cu criteria. Additionally, in the absence of empirical results for calibration of a saltwater Cu-olfactory model, we demonstrate that a proposed unified freshwater-saltwater Cu-olfactory BLM predicts the US EPA?s current saltwater Cu criteria would be protective against olfactory impairment caused by Cu in sea water.

Feb 27, 2013

By Hongbo Zhao, Jun Wang, Wenqing Qin, Guanzhou Qiu, Xueduan Liu

Bio-hydrometallurgy technology was applied for the extraction of copper from the raw ores of Chambishi Mine in Zambia. A copper extraction of 93.29% was obtained for small scale column bioleaching within 63 days, while a copper extraction of 89.05% was achieved for large scale column bioleaching in 90 days, thus confirming the amenability of the raw ores for effective extraction via bioleaching. The bacteria were cultured in a 6-stage enlarge cultivation. The bacterial cultures with cell concentration of more than 1×108 cells/mL were added into a spray pond of sulfuric acid to be applied in the dump leaching, and a copper extraction of about 50% was achieved within 2 months. The production report revealed that the copper extraction increased by approximate 20%, and the acid consumption was reduced to around 35% as a consequence of adding the bacteria. The industrial demonstration of the bio-hydrometallurgy technique is now well established in Zambia, and further applications of bio-hydrometallurgy in both Zambia and Congo are currently in progress.

Jan 1, 2015

By J M. F Clout

The Roy Hill Project is an independent integrated port, rail and mine development in the Pilbara region of Western Australia. The bankable feasibility study for the project was completed in January 2011 by Roy Hill Holdings Pty Ltd, a wholly owned subsidiary of Hancock Prospecting Pty Ltd. The Project will deliver 55 Mt/a of premium quality iron ore to a rapidly growing market with a mine life of over 27 years. This study is based on exploiting a 1.2 Bt bedded resource of microplaty haematite-rich Marra Mamba, from which 562 Mt of reserves has been delineated to date. A further 1.1 Bt resource of detritals and low grade bedded is proposed to be mined once the bedded high grade resource is depleted. Roy Hill lump and fi ne ore products will compete strongly with other Pilbara products. As a low cost producer, Roy Hill is on track to capture four per cent of the global seaborne traded iron ore market. The project decision to proceed is targeted for Q2 2011 to enable first ore on ship by Q2 2014.

Jul 11, 2011

By P. T. O'Kane

"INTRODUCTION Wright Engineers Limited is active and has extensive experience in the design of pressure oxidation plants for the treatment of refractory gold ore and concentrate. In addition to the Mercur oxidation facility, similar projects undertaken during the last few years include the 3000 ton per day acid oxidation plant for the Getchell Mine, Nevada, a concentrate treatment autoclave for Asamera in 1984 and a feasibility study of a 50-tons per day autoclave plant for Consolidated Professor's Duport property in Ontario. The Equity Silver antimony and arsenic precipitation autoclaves, and the low pressure autoclaves at Key Lake Uranium in Northern Saskatchewan were also engineered by Wright in recent years.In August 1986, Wright was retained by Barrick Resources (U.S.A.) Inc. to add a 750 tpd pressure oxidation circuit to the existing mill at their Mercur Gold Mine, Utah. This paper describes this facility and outlines the start up in the spring of 1988 and subsequent successful operation. MERCUR OPERATION The Barrick Mercur Gold Mine is located at the south end of the Oquirrh Mountains in Tooele County, Utah. The carbon-in-leach (CIL) process plant camnenced operation in 1983 with a design throughput of 3000 tpd and has since been expanded to handle rrore than 5000 tpd. 'IWo ore types are mined, an oxide ore and a refractory ore, which is by Barrick's definition ""an ore from which less than 60% gold extraction is achieved by a standard CIL amenability test."" Typical of many sulphidic/carbonaceous ores, the refractory gold does not respond well to the cyanidation process. As a result, refractory ore has been stockpiled since the start of mining. As of June 1987, Mercur had about 570,000 tons of refractory ore stockpiled and 5.7 million tons of proven and probable reserves, grading 0.06 oz/t including approximately 3.5 million tons of tailings from the previous operation grading 0.55 oz/t. In 1986, Barrick decided to build a 750 ton per day pressure oxidation plant to process these ores. The process, for which a patent was granted, comprises pressure oxidation of the sulphides in an alkaline environment. It was developed in 1981 but was set aside in preference of a CIL plant treating only oxide ores by the previous owner of the property, Getty Oil. This process is capable of increasing gold recovery from the refractory ore from as low as 35% by conventional CIL processing to more than 85%. In 1986 Wright Engineers was engaged to undertake a feasibility study based on batch testing. This lead to a decision by Barrick Mercur later that year to build the commercial pressure oxidation plant. Wright was awarded the contract for engineering, procurement, construction managernent and commissioning in March 1987. The plant was mechanically complete in January 28, 1988, and was in operation by February 1988."

Jan 1, 1989

By Luís Carlos da Silva

Vários motivos levaram a priorizarem o uso de fibras naturais em detrimento do uso de fibras sintéticas, sobretudo as razões sociais e ambientais. A fibra deste trabalho é extraída da folha da planta - Furcraea Andina (da Colômbia, onde usam esta fibra para a produção de artesanatos e sacos) e demonstra um grande potencial como reforço de compósitos poliméricos. Este trabalho avaliará o teste de impacto de Izod e Charpy de compósitos com matriz epóxi reforçada com diferentes porcentagens de fibras. Para os testes, as fibras de fique foram misturadas com à resina epóxi em um molde metálico retangular, o conjunto foi submetido a uma pressão e sofreram um processo de cura à temperatura ambiente durante 24 horas. As amostras produzidas foram submetidas aos ensaios seguindo a norma ASTM D256 (Método de Ensaio Padrão para à Determinação da Resistência ao Impacto do Pêndulo Izod para Plásticos) e a norma ASTM D6110 (Método de Ensaio Padrão para Determinar a Resistência ao Impacto Charpy para Plásticos). Os compósitos continham até 30% em volume de fibras de fique, que foram alinhadas ao longo de todo o comprimento da matriz. As amostras submetidas à ambos os ensaios (Izod e Charpy) tiveram suas fraturas analisadas por microscopia eletrônica de varredura (MEV). Houve um aumento significativo da resistência ao impacto de acordo com o aumento da porcentagem volumétrica das fibras de fique. Esse desempenho pode estar associado ao mecanismo de fratura gerado a partir da adesão entre as fibra de fique e a matriz colaborando na absorção da energia de impacto, além do fato de que a fibra é capaz de dificultar a ruptura das amostras.

Oct 30, 2017

By S Gulati, N Sarkar, T Vink, S Battersby, L Okada

This paper examines a successful project implemented by BHP Mitsubishi Alliance (BMA) and the Polymathian team at Deswik, aimed at enhancing short-term scheduling processes to reduce vessel turn times in the BMA Central Queensland coal value chain. The project’s objective was to digitalise the planning process to enable planners to make data-driven insights to improve the profitability of the value chain. The strategy involved developing a digital mining system that incorporates data storage, cloud computing, and the ability to meet the integration needs of both internal and external business systems. This was complemented by a sophisticated, optimisation-based, decision-support tool to enhance the planning teams’ ability to make timely and effective decisions.

Sep 1, 2024

By Christopher Snee

??care has to be taken that the design is driven by sound geological reasoning and rigorous engineering logic rather than by the very attractive images that appear on the computer screen.??Hoek 1999 Design of a cavern is inextricably linked to the engineering geology of the site. The importance of sound geological reasoning will be illustrated by transportation projects in New York City where there are proposals for at least 11 caverns. These caverns have been the subject of advanced exploration techniques and geological interpretation but even so the raw data falls short of the sophistication of modern numerical methods. This paper will give geological explanations for the engineering characteristics of the rock in New York City which will provide guidance for practitioners when approaching cavern design in New York and elsewhere.

Jan 1, 2008

MFIRE is a computer simulation program that performs normal ventilation network planning calculations, and dynamic transient state simulation of ventilation networks under a variety of conditions. The program is useful for the analysis of ventilation networks under thermal and mechanical influence. MFIRE simulates a mine's ventilation system and its response to altered ventilation parameters, external influences such as temperatures, and internal influences such as fires. Extensive output enables detailed quantitative analysis of the effects of the proposed alteration to the ventilation system Network simulation using digital computers has become widespread throughout the mining industry in recent years. However, as the sophistication of the simulator increases (MFIRE, for example), the complexity of input data requirements and interpretations of results requires more skill and knowledge from the users. Perhaps the most difficult part of using MFIRE is to construct the data set describing the mine's physical layout and its ventilation properties. The initial attempts to get the data set running often reveal unknown or ignored aspects of the mine's ventilation. MFIRE was written in Fortran 77 and compiled with Microway1 Fortran for the Intel 80386 based computers with a 80387 math co-processor. The source code is portable and available for users who wish to modify the source code to operate on other computers. This user manual describes the development of MFIRE, the input format and requirements, the output, common errors, fire parameters, and examples MFIRE application. Valuable reference material is included in the appendices. Knowledgeable users may skip directly to the PROGRAM INSTALLATION AND OPERATION section to begin using MFIRE immediately.

Jan 1, 1995