Search Documents

Jan 1, 2001

By Ashis Bhattacherjee, Rahul Upadhyay, Nearkasen Chau, Aditya Kumar Patra, Dhanjee Kumar Chaudhary

Heavy earth-moving machineries used in open-pit mines intensively expose the drill operators to whole-body vibration and shocks and thus to musculoskeletal disorders. The roles of an individual, machine, and rock-related factors in their exposure remain poorly understood. This cross-sectional study investigated their role among 39 drill operators from Indian iron ore mines. It shows that 70% of the operators were exposed to high levels of vibration, above the limit values recommended by ISO 2631-1. Multiple linear regression models showed that the whole-body vibration and shock exposures were strongly associated with operator’s age, drill machine model, rock’s hardness, uniaxial compressive strength, and density. The role of body mass index was close to significance (p = 0.08). Univariate analyses found that drill’s age, seat pad thickness, and seat backrest height were also strong predictors. These results help in identifying risky operators, materials and occupational situations, and in implementing appropriate prevention and intervention to reduce and monitor the exposures and health risk.

By C. Siac

"It is a widely held view that in the 21st century, the mining industry will be dominated by a relatively small number of large companies, truly global in scope and internationally staffed (Gooding, 1997). Interestingly enough, most of the exploration and exploitation activities are being carried out by junior and major mining companies from common law jurisdictions in civil law countries, in particular in Latin America, where in recent years, the region has ranked first as a destination for exploration dollars, thanks to the reforms undertaken by some countries to amend their legal framework to attract foreign investment. From a lawyer’s point of view, this is where the main challenge lies: how to bridge the gap between the two legal systems.In order to avoid pitfalls, common law lawyers should be more diligent and proactive when dealing with civil law jurisdictions, given the different systems of law, standards, traditions and customs. Common law lawyers cannot be expected to be well-versed in civil law but they should not be completely unfamiliar with it either. A balance should be struck to ensure clients’ needs are professionally taken care of and that common law requirements and standards are met."

Jan 1, 2003

By S. Banisi, E. Arghavani, A. Akbari, Gh. A. Parsapour, S. Darvish Tafvizi

The new copper processing plant of the Sarcheshmeh copper complex consists of two parallel circuits. After a primary crushing, the ore is sent to a SAG mill and the product is further ground in a ball mill. The overflow of the hydrocyclones is fed to a flotation circuit which contains 8 rougher tank cells (RCS130), 3 cleaner cells (RCS50), 5 scavenger cells (RCS50) and a 4 x 12 m flotation column as recleaner. The circuit was initially designed to process a feed containing 0.8% Cu, but because of the ore type change, the feed grade decreased to 0.6% Cu. This resulted in a reduction of final concentrate grade and recovery from 28 and 85.5% to 24 and 84.4%, respectively. Based on the original design, the copper and silica recovery in the cleaner cells should be 69 and 55%, respectively, but these values increased to 85 and 75% because of a higher retention time. The rather high silica recovery (i.e., 75%) was found to be the main source of the lower final concentrate grade. In order to reduce the retention time of particles in the cleaner cell from 13.7 to 6.9 min, the rougher concentrates of two parallel circuits were fed to only one cleaner-scavenger and regrind circuit. This modification increased the cleaner and final concentrate grade from 15.1 and 24.5% to 17 and 26%, respectively. To prevent a possible reduction in the copper recovery, the froth depth in the scavenger cells was reduced. The overall outcome of the circuit modification was evaluated to be a 10% reduction in the energy consumption without any loss in the overall copper recovery.

Jan 1, 2016

By Michael J. Friedel

As part of an investigation aimed at mitigating the hazards caused by abandoned mine openings, the Bureau of Mines conducted a series of electromagnetic surveys in the Galena, KS, area of the Tri-State mining district. The application of monostatic ground-penetrating radar (OPR) and inductive electromagnetic methods for detecting and delineating hazardous mine openings and attendant features was demonstrated to be feasible for shallow mine workings (i.e., less than 35 ft) occurring below flat-lying areas. Accurate determinations of depth to a mine roof appeared to be limited to roughly 20 ft using the GPR method. Features such as mine voids, fractures, and zones of subsidence were located beneath the Mainstreet (State Highway 26) site using the GPR system. Both the GPR and inductive electromagnetic techniques satisfactorily located mine openings and pillars at the Hell's Half Acre site. Geophysical interpretations were supported by exploratory drilling and mine maps.

Jan 1, 1990

Jan 1, 1967

By MOHAMMED AMINE BELMI, ANAS DRIOUCH, ABDELAZIZ LAHMILI, LATIFA OUADIF

For many years, underground workings in the Bou Azzer mine have been challenged by geotechnical problems related to the serpentinite instability. The stage of evaluation of the compression potential is crucial to develop an appropriate drilling method and the choice of non-standard support. This research work presents a retro-analysis of serpentinite behavior in underground excavations at different depths, using a multi-approach method, based on several empirical and semi-empirical and theoretical-analytical methods, calibrated by the observational method. The analysis performed in this work reveals that underground excavations in Bouazzer East and Ait Hmane area would encounter compression problems that were recognized as the most serious from a depth of 300 m because of the effects of lithology and tectonics. Therefore, the Aghbar region has a slightly negligible compression potential. The compressive failure mechanism in this mine, depending on the mechanical strength, is started at induced stress of 9 MPa.

Nov 27, 2021

By George A. Morgan

The production and processing of crude petroleum and natural gas are the dominant economic sectors of the Middle East. Downstream processing of these mineral fuels to petrochemicals and fertilizers is a major investment opportunity. In 1991, the 15 countries that constituted the region accounted for 26 % of world crude petroleum output, 15.3 % of world natural gas plant liquid production, and 4.5 % of world dry natural gas production. Only Cyprus and Lebanon were not crude petroleum producers. Production of these mineral fuels all declined from that of 1990 owing to the Persian Gulf War, during which output from Kuwait and Iraq either ceased owing to war damage, or was embargoed. Prior to the war, Iraq and Kuwait were the fourth and fifth largest world producers of crude petroleum, respectively. In the war, virtually all of Kuwait's production and transport facilities were destroyed or damaged. Iraq's output was embargoed from export, with only domestic sales taking place. The embargo also affected Jordan, both in terms of transshipment of materials through it to Iraq and in exports of phosphate and potash. Shipments of crude petroleum by pipeline from Iraq through Saudi Arabia and Turkey and by vessel through the Persian Gulf were terminated. However, the loss in production from Iraq and Kuwait was made up by accelerated output from other Middle East and world producers. Saudi Arabia, in particular, with its excess production capacity, accounted for the largest portion, increasing crude petroleum output by 27 % to almost 3 billion barrels.

Jan 1, 1993

By M. Nagamori, A. J. Plumpton

"Commercial HCl-leaching of magnesite and serpentine yields highly concentrated aqueous solutions containing 25 mass % to 33 mass % MgCl2. The partial molar enthalpies and heat capacities, the ionic activities of Mg2+ and Cl–, and the Raoultian activity of H2O have been assessed for the concentrated MgCl2-H2O solutions at temperatures of 348 to 373 K. These thermodynamic data are used to calculate the pH of aqueous MgCl2 solutions saturated with a Mg-bearing mineral such as magnesite, serpentine, brucite, forsterite, enstatite or talc. On the basis of these thermodynamic data, technico-economic aspects are discussed as to neutralization with pulverized MgCO3, water evaporation from the MgCl2 solutions, and ore composition including such minor constituents as CaCO3, FeCO3 and Fe3O4. IntroductionA major magnesium electrolytic reduction plant operates in Quebec, where another will begin its production in the year 2000. One uses imported magnesite ore as raw material, while the other will utilize local asbestos tailings (serpentine). Both processes produce a concentrated salt solution of 25 mass % to 33 mass % MgCl2 by leaching the ore with concentrated hydrochloric acid. Thus, the two processes differ mainly in the HCl-leach and related operations. After the HCl-leach of the ore, the serpentine process yields about 25 times more wet cake to filter and wash than the magnesite counterpart. A comparative cost-engineering study with respect to slurry filtration and cake washing has been published elsewhere (Blackburn and Nagamori, 1994). By contrast, the present study considers the thermodynamics and technicoeconomics of the HCl-leach itself for both ores."

Jan 1, 1999

By Richard L. Sanford

This report summarizes the results of the development of a Directory of Computer Programs Applicable to U.S. Mining Practices and Problems. The Directory includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various U.S. government agencies. References to computer applications throughout the mining industry are presented as well as comments on the availability of programs to interested organizations or individuals.

Jan 1, 1977

By M. O?Driscoll

The tide has turned. Developments in China that have continued to unfold over the last four years or so have now reached a point where the supply market dynamics of certain industrial minerals have changed significantly. No more is this sea change better exemplified than by the supply market for magnesite, and in particular, its processed derivative grades of dead burned magnesia (DBM), caustic calcined magnesia (CCM), and fused magnesia (FM). But what has compounded the barrage of influencing factors impacting this sector, which include the widespread effects of energy and freight cost increases, has been rising demand from certain end use markets. Clearly, the magnesia market is experiencing bittersweet conditions. But those western producers which have monitored and responded to this market transformation, stand to taste success in the near and medium future. REVOLUTION IN WORLD SUPPLY STATUS In essence, while China, as host to a wealth of magnesite resources in Liaoning province, remains a huge producer of magnesia, its supply dominance on the global magnesia market has been considerably weakened. In future, it will mainly aim to supply domestic, and to some extent east Asian markets. Magnesia consumers outside China are now scrabbling for alternative, ?western? sources of supply. At the same time, magnesia producers outside China that weathered the storm of low cost Chinese DBM and FM imports flooding their regional markets for the last 20 years (and many did not), are busy investing in production capacity increases to meet not just demand from falling Chinese supply, but also demand from end use markets which is picking up. And it is not just a matter of expanding capacity of existing magnesia product lines. In the face of plentiful lower cost DBM and FM substitutes from China over the last couple of decades, many western magnesia producers started to switch their focus to the non-refractory markets (eg. environmental, specialities) which promised lucrative opportunities (and still do) and crucially, a lessening of sales revenue dependence on the DBM refractories market. Now we have the likes of Baymag (Canada), Bommag (Serbia/Turkey), and Kumas (Turkey) not only expanding capacities but seriously considering diversifying into DBM and FM production. Perhaps DSP (Israel), having ceased its famous high purity DBM activity as recently as 2005, might even reconsider a return to the ?other side?. But it?s not all DBM and FM. The CCM and specialities markets are also demanding a response, and so Baymag, DSP, Martin Marietta (USA), Premier Chemicals (USA), Qmag (Australia), MGR (Spain), and Magnifin (Austria) are also stepping up to the market on the non-refractory side. From most accounts, the situation with regard to Chinese supply has been described as one of turmoil, with prices rising, leading to improving opportunities for western producers. The majors are conducting huge expansion programmes, such as Qmag, Magnezit (Russia), and the new look Magnesita (Brazil). Even smaller players such as Causmag (Australia) and Dalmia (India) are looking to increase production. In short, the western magnesia supply sector is witnessing a landmark event in capacity investment and market share penetration as China?s previously dominant role begins to weaken (for a review of western capacity expansions see Industrial Minerals, September 2008, p.28). MERGER & ACQUISITION ACTIVITY Another response of course has been a raft of mergers and acquisitions in order to secure resources and supply outside China. These have included private equity groups taking over Magnesita and Qmag; Imerys entering the FM business through UCM; Peñoles further consolidating the electrical grade FM market by acquiring Minco; Martin Marietta acquiring Morton Salt?s Specialty Magnesia Group; Bomex entering the market through Calmag (now Bommag); LWB acquiring Magnesita; and Magnezit?s pursuit of Slovakian magnesia, with Slovmag aboard while currently wooing SMZ. Interestingly, RHI has gone ?the other way?, and has invested in a state of the art joint venture operation at Dashiqiao, Liaoning, with which it aims to secure high quality feedstock for its Chinese refractory plants. Tata Refractories Ltd has announced intentions to follow suit, and other majors, such as Qmag are known to be interested in seeking options. Naturally, there is now renewed interest from several parties in the idled 50,000 tpa DBM/10,000 CCM Jormag facility, Jordan, and the commercially undeveloped Zhargat project, Saudi Arabia. Elsewhere, there will no doubt be suitors for stakes in SMZ, in Slovakia, and Magnohrom, in Serbia, whose respective ownerships are on the block. THE ?CHINA FACTOR? The ?China factor? has been key to magnesia?s market change, and has significantly influenced prices and availability of material to global markets. Resources & production China hosts the largest share of the world?s magnesite deposits, accounting for 26% or 3,319m. tonnes of predominantly sparry magnesite (followed by North Korea, 24%, and Russia, 22%; Wilson 2008). China accounts for 44% of total world magnesite mined (19m. tonnes in 2007) and 50% of the total world magnesia produced (8.2m. tonnes CCM, DBM, FM; Wilson 2008). Russia follows China at 13% of magnesia supply, illustrating China?s dominance of magnesia production. Apart from one producer in Shandong province, central eastern China, the country?s magnesite resources and production are concentrated around the cities of Haicheng and Dashiqiao in Liaoning province, north-east China. Although there are also producers in the Xiuyan district of south-east Liaoning, the Haicheng-Dashiqiao Magnesite Belt hosts the majority of producers. In total these may number 200-300 of large,

Jan 1, 2009

By Afrânio Márcio Costa

Placas lingotadas continuamente, não obstante atendam a requisitos como composição química, conteúdo de inclusões, aspectos macro e micrográficos, podem ser desclassificadas por falta de conformidade dimensional. Contrações térmicas, de solidificação e de transformações de fases são partes intrínsecas do processo e são afetadas por alterações na taxa de extração de energia da placa durante o processo. Este conjunto de contrações determina o Fator de Contração de operação, o qual é utilizado para determinar as dimensões do molde que irão resultar na largura especificada, onde o presente estudo determinará o fator de contração dos aços peritéticos. As variáveis identificadas que influenciam no fluxo de calor primário foram: frequência de oscilação, superaquecimento, velocidade de lingotamento e viscosidade do pó fluxante. Identificou-se que o resfriamento secundário e a conicidade utilizado no molde, também são critérios determinantes para obtenção de larguras especificadas. Assim sendo, uma equação de regressão foi desenvolvida para o Fator de Contração.

Aug 17, 2017

By Fernanda da Silva Machado

Em um mundo de recursos naturais decrescentes, com a intensificação das indústrias automatizadas de todos os tipos (I4) e contínuo aumento da população, é necessário desenvolver melhores caminhos para a geração e distribuição de riquezas. Uma das alternativas para este objetivo é o conceito da Economia Circular. Este artigo apresenta um exemplo focado na intensificação do uso de resíduos de biomassa na produção integrada de aço exclusivamente baseada na combinação de reatores industriais existentes em um layout que favorece o conceito da economia circular. O ferro também é obtido do processamento tradicional de sucata, reprocessamento de resíduos de ferro e óxidos de ferro, como a escória, pequenos óxidos de ferro, reversos metálicos, resíduos da indústria siderúrgica integrada tradicional. Os resíduos de biomassa são provenientes da demolição de casas de madeira, e outros resíduos de biomassa, como limpeza florestal para evitar-se incêndios, resíduos de moinhos, paletes usados e qualquer outra fonte de biomassa. As combinações dos reatores tornaram-se possíveis devido à nova versão do processo de Carbonização Contínua, Carboval, um reator especialmente projetado da tecnologia Lambiotte tradicional, para produzir, de preferência, o carvão vegetal que possui as mesmas características necessárias para alimentar o Mini Alto Forno tradicional a base de carvão.

Oct 30, 2017

By Floyd R. Hertweck

The helium resources of the United States were estimated by the Bureau of Mines to be 1,037 Bcf as of January 1, 1981. These resources are divided into four categories, in decreasing degree of assurance of their existence: (1) helium in storage and in measured natural gas reserves, which totals 211 Bcf, (2) helium in indicated natural gas resources, which is estimated at 207 Bcf, (3) helium in hypothetical natural gas resources, which is estimated to be 318 Bcf, and (4) helium in speculative natural gas resources, which makes up the remaining 301 Bcf. These helium resources are further divided into depleting, nondepleting, and stored classifications, The depleting resources are those associated with natural gasfields that are, or will be, produced for the natural gas they contain. All of the helium in undiscovered (hypothetical and speculative) natural gas resources is included in this classification. These depleting resources are estimated to contain 897 Bcf of the total helium resource base. Nondepleting resources are those in shut-in, abandoned, or otherwise nonproducing natural gasfields. Helium resources contained in nondepleting natural gas resources are estimated to total 100 Bcf. There is 40 Bcf of helium in storage in the Federal Government-owned Cliffside Gas Field near Amarillo, Tex.

Jan 1, 1983

By Lewis V. Wade

This paper summarizes the results of the rock mechanics monitoring program performed as part of Old Ben Coal Company's longwall coal mining demonstration project conducted in cooperation with the United States Bureau of Mines. The work described herein included installation of instruments, collection of data and data analysis performed during mining of the first longwall panel in Mine No. 24. The rock mechanics monitoring program included both surface and underground instrumentation and was designed to achieve the following purposes: 1 -To provide the capability to observe unusual situations during mining so that remedial measures could be instituted quickly 2 -To formulate design guidelines for future longwall mining efforts; 3 -To evaluate surface subsidence, and its character, rate and potential effects on cultural features, and to develop criteria to assist in predicting subsidence for other mines having similar roof conditions. Six previous attempts with longwall methods in Old Ben Coal Company's Hine 21 had been unsuccessful due to roof control problems. A description of these attempts is given by Moroni (1973). In preparation for the present longwall operation a study was performed to review existing data on the previous unsuccessful attempts, to establish coa1-and floor-strata bearing capacities in Mines Nos. 21 and

Jan 1, 1977

By Raymond Chenier

British Columbia (BC) is Canada’s most western province. The landscape in BC is amongst the most beautiful and pristine in the world. Along with its beauty come vast mountain ranges, coastal rain forests, swamplands, deep river valleys, and almost every type of landscape imaginable. These all have, or at one time had, logging roads constructed. Some of these areas should never have had roads constructed due to poor drainage and unstable slopes, but some of the roads could be considered engineering masterpieces. To navigate a vehicle the size of an off-road logging truck down the side of a mountain with an 80°h side slope or greater can be a hair-raising experience. Not to mention coastal rains and/or high elevation blizzards. These factors collectively make logging BC’s most hazardous occupation. People are seriously hurt, sometimes even killed everyday.

Jan 1, 2001

8053. Andreev, B. A. Zakashanakii, M. S., Samsonov, N. N., and Fotiadi, E. E. A Textbook of Gravitational -Surveying, (in Russian). Gosgeolizdat, Moscow-Leningrad, 1941, 432 pp. This textbook was written at the suggestion of-the faculty of geophysical exploration of the Leningrad Mining Institute. It contains two parts: (1) Theory and technique, and (2) Applications to geology and exploration. The features bringing; the text up-to-date include: (a) Description of the principal modern gravimeters; particular attention to the method of simultaneous oscillation of 4 pendulums; (b) discussion of the aperiodic oscillation of torsion balances; outline of the construction of variometers Z -20 and Z-40; (c) material for aid in interpretation, such as reference-charts, formulas with their derivation, atlas of theoretical curves, and examples of interpretative calculations; (d) considerations in the planning of surveys and the densities of various rocks; and (e) detailed analysis of significant examples. The text is provided with a bibliography, V. S.

Jan 1, 1946

By J. Weng

The equations of heat conduction are numerically solved for two kinds of artificial freezing- mechanical freezing and liquid nitrogen freezing. A two dimensional finite difference model simulating the freezing field is developed. The procedure introduces a way to simulate the effect of latent heat released when water transforms from liquid to solid. The procedure also produces a way to calculate the harmonic mean of heat conductivity used when dealing with heterogeneous material. The theoretically derived temperature distributions in frozen soil are given and compared with measured data. An analysis is made on the thermal design in shaft freezing. The average temperature of frozen soil is calculated by using numerical integration. The regularity of development of frozen soil radius is revealed and given in an appropriate mathematical model.

Jan 2, 1984

By S. Klingmann, G. Blackwell

"Terrestrial photogrammetry has been used for many years to build three-dimensional pictures for analytical purposes. Photographs can include images from open pit mine walls, ground topography, mine buildings infrastructure or accident scenes. Analysis and co-ordinate estimation in early photogrammetric systems demanded the use of specialized and costly optical-mechanical stereocomparators. Few of these instruments could be interfaced with computers to provide databases, and all required trained personnel with good perspective vision to collect data.Digital photogrammetric software has replaced these older systems, and the digital video plotter (DVP) is a simple computerized system utilizing readily available PCs to quickly produce a stereoscopic model of any scene where an area of overlap exists in photographs taken from two different locations. Specialized cameras providing reference marks or grids on the photographs are still necessary for detailed analysis in three dimensions.This paper describes the application of DVP to the three-dimensional analysis of strike, dip and location of dominant fracture planes visible on an open pit wall slope, and the intersection of planar features which might reduce wall stability. Where reference survey points cannot be provided because access by personnel to the photographic scene is impossible for safety reasons, normal case terrestrial photogrammetry can provide the necessary control points for more complex aerial photogrammetry geometries.DVP recreates the geometry existing at the moment photographs are taken, providing the user with the ability to safely recreate, compare and analyze the structures determining the stability of open pit wall slopes."

Jan 1, 2003

Commercialisation of outcomes from research projects is a process often poorly understood and managed, but has the potential to achieve significant benefits for the industry and community as a whole. JKTech Pty Ltd was established in 1986 to transfer viable research outcomes from the Julius Kruttschnitt Mineral Research Centre (JKMRC) at The University of Queensland, Australia. This paper describes successful and unsuccessful examples of commercialisation by JKTech over the years, and draws some conclusions as to the factors that contribute to success and failure in technology transfer.

Jan 1, 2012