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By K D. Wilkes

The WEMCO Heavy Media Drum Separator was first introduced by WEMCO in California in the 1940`s, initially from their base in San Francisco and later when the company moved to Sacramento. The WEMCO Company became a part of EIMCO Process Equipment in 1985, and in 2002 EIMCO became a part of the GL&V Group when Dorr-Oliver EIMCO was created. Throughout this period of time the WEMCO Drum has been installed on a variety of different applications and is now operating at the heart of many of the world?s largest Minerals and Coal Processing Plants, as well as being used by many smaller producers and metal re-cycling operations. This paper looks at the practical aspects of using WEMCO Drums in a representative range of processing applications.

Jan 1, 2006

By Michael Kelly

Inertial navigation technology has, for the first time, allowed the position of a longwall shearer to be mapped in three dimensions. Following the success of the technology in highwall mining and successful trials on a longwall face, the Australian Coal Association Research Program (ACARP) commissioned a three year "Landmark" project that aimed to advance longwall automation to the level of "on-face observation" by the end of 2004. This project has been completed with the following successful technical outcomes: Automatic face alignment was achieved, using an inertial navigation-based sensor on the shearer, to accurately measure face geometry and feedback signals used to move OEM (Original Equipment Manufacturer) roof supports. Operational on-line measurement of creep with creep information incorporated into face alignment corrections. Inertial Navigation System (INS)-based enhanced horizon control was bench-tested. Operational broadband communications system to shearer using wireless Ethernet on a commercial-product basis. Acquisition of located coal-face features for use in thermal infrared-based horizon control. Automated Longwall Information System (LIS) developed which integrates information from multiple systems and sensors and provides high quality visualisation and control interfaces. Automatic roadway and face convergence monitoring tools successfully tested. Condition monitoring tools developed and demonstrated for improved face reliability. This paper summarises the outcomes of the project and describes the work being undertaken for the 2 year Landmark Extension project approved in April 2005. Consistent with the conference theme, the paper focuses on the ground control aspects of the project.

Jan 1, 2005

By Shimi Tzobery, John E. Shamma, Samuel Swartz, Gary B. Hemphill

The trapezoidal tapered ring method has made significant progress in recent years for shielded-TBM projects, excavating tunnels with high overburden, strict water tightness criteria, and multiple curve alignments. The selection of compatible tapered rings is critical for successful advancement of the tunnel, assuring efficient installation of rings, as well as prevention of ring damage and excessive leakage. Using experience from the Arrowhead Tunnels Project, this paper describes guidelines for ring selection in tunnel curves, geometric analyses that comply with criteria principals, and provides techniques developed to determine the appropriate relative key position.

Jan 1, 2005

By Luis Valdivia

Dado que el objetivo principal de un departamento de Geología de exploraciones es el de estimar recursos minerales en nuevos blancos de exploración identificados a través del análisis e interpretación de información geológica proveniente de diversas fuentes. En ese sentido, el presente texto señala la sistematización de los datos geológicos como el uso de las imágenes satelitales, fotografías aéreas, geofísica, geoquímica, cartografiado geológico, sondajes diamantinos, catastro minero, datos geográficos y políticos, etc. a través de un servidor que integre dichas estructuras lógicas de conocimiento, de manera que todos puedan acceder a ella de manera fácil y dinámica. Asimismo, para los datos de carácter numérico llámense muestras, sondajes, leyes, se utiliza la plataforma Access como gestor de base de datos, mientras que para la información grafica superficial, el software ArcGis.

Sep 24, 2008

By D. M. Muir

Thiosulfate offers a non-toxic alternative to cyanide for processing gold ores. The mechanism of leaching gold using ammoniacal thiosulfate solution is driven by the Cu(II)-Cu(I) redox couple and is complicated by competing ligands such as NH3 and S2O32-. It is shown that an understanding of the copper speciation and sulfur speciation is required to optimise this system. This paper presents Eh-pH and speciation diagrams for varying concentrations of Cu(II), S2O32- and NH3 and discusses the conditions under which various copper and sulfur species are stable.

Jan 1, 2001

By A. Mboma

Keywords: Furnace, decommissioning, care and maintenance, re-start, funding, nickel Bindura Nickel Corporation (BNC) operates two nickel mines, and treats concentrates from these mines as well as toll concentrates from the region around its Bindura Smelter and Refinery (BSR) complex. At the smelter, concentrates of at least 5% nickel content are blended and dried to 4% moisture in a coal-fired rotary kiln. Matte smelting of concentrate is carried out in a six-in-line electric arc furnace, where the furnace slag is granulated and discarded. Furnace matte is transferred via ladles into Peirce-Smith converters, where, after granulation, a leach alloy containing 68%Ni, 20%Cu, and 6%S is produced. Converter slag is recycled via the matte-smelting furnace. The onset of the global economic recession towards the end of 2008 resulted in a collapse of metal prices, worsening the local situation that was already marred by unfavourable macro-economic conditions in Zimbabwe. As a result, BNC mines were put on care and maintenance in November 2008, followed by Bindura Smelter and Refinery in February and March 2009 respectively. The business environment has since changed, and BNC is getting ready to re-start the plant. This paper describes the decommissioning of the Bindura furnace, asset preservation during the care and maintenance programme in the past two years, and preparation for starting up of the Bindura smelter in the near future.

Jan 1, 2011

By Claude Bazin, François Robichaud

"The control of the operation of semi autogeneous grinding (SAG) mills is mainly achieved through adjustments of feed rate, water addition and speed of rotation. With the introduction of image based sensors it is possible to have on-line measurements of the size distribution of the ore feeding a SAG mill. This information could be used for the development of a control strategy to regulate a SAG mill feed size distribution to a set-point. The control of the size distribution is carried out by adjustment of the speed of the ore extractors underneath the ore stockpile. The potential and difficulty associated with the implementation of such control are assessed using a multivariable statistical analysis of data collected from the operation of the grinding circuit of the Agnico-Eagle Goldex mine in Val d’Or, QC. A control strategy for the ore feed size distribution is assessed using a simulator of the ore stockpile operation.INTRODUCTIONThe popularity of autogeneous (FAG) and semi autogeneous (SAG) grinding mills has been increasing over the last 20 years (Napier Munn et al., 1996). These mills use the ore or a combination of ore and steel balls as the grinding media. Since the ore is used as a media for the size reduction the mill ore feed size distribution impacts the performance of the mill. Several papers were recently published on this subject (Dance et al.,2011; Wennen & Murr, 2011; Dance & Valery, 2011; Allaire et al., 2011) showing the advantages of preparing the feed size distribution to maximize the circuit throughput or mill efficiency (Wennen & Murr, 2011; Dance & Valery, 2011; Allaire et al., 2011). With the availability of particle size sensor based on image analysis of the ore on a conveyor (Partanen et al., 2001; Bobo et al. 2004; Edwards et al., 2002; Wei & Craig, 2009) it is possible to control the size distribution of the ore feeding autogeneous or semi autogeneous mills (Partanen et al., 2001).This paper describes a method to control a size distribution index to a set point via the manipulation of the speed of the extractors that withdraw the ore from the stockpile feeding the grinding circuit. The paper consists of 4 sections. The first section describes the considered grinding circuit. A statistical analysis of the collected data on the grinding circuit is presented in the second section. This analysis demonstrates the necessity of using real-time adaptation mechanisms to develop a control strategy for the size distribution of a grinding circuit. The third section describes the method used to simulate the ore stockpile operation and the last section describes the preliminary development and assessment of a control strategy of size distribution of the ore feeding a SAG mill."

Jan 1, 2013

By W. H. C. SIMMONDS

The mining, metallurgical, and petroleum industries can be viewed as financial or as social institutions or both. The differences between these two conceptions of their businesses will influence their environmental 'and social actions. During the next 10-20 years western industry will be subject to a drop in the growth of a more highly educated labour force and to the emergence of holistic economics, new national goals, and a new ecological perspective. The profitability of the mining industry may therefore be influenced by the human side of its business to a greater degree. The increasing human, social, and environmental responsibilities can be discharged by improving the miner's equipment; by learning to look at situations through the eyes of all those involved; by developing common 'languages' which governments and the public can understand; and by mediating where feasible on the international scene.

Jan 1, 1978

By L. B. Berger

From time to time the Bureau of Mines receives requests for information and advice regarding the safety of using internal-combustion engines operated on butane fuel as prime movers for haulage and other purposes in mining and tunneling. The purpose of this, circular is to discuss the properties of butane and to present data in regard to the possible use of this fuel in underground operations. Published information on the use of commercial butane as a fuel for internal-combustion engines indicates that, insofar as performance is concerned, butane may be utilized satisfactorily and efficiently for this purpose. However, the introduction of a volatile, inflammable material such as butane into confined spares such as mines or tunnels would create potential fire and explosion hazards that should be given due consideration by those concerned with the promotion of safe practices.

Jan 1, 1944

By Hon-Yim Ko

1972 constituted the second year of the projected five-year study on constitutive relations of coal. The schedule adhered closely to the five-year outline which is summarized in Table 1. This chapter is intended to serve as introduction and concise synopsis of the year's activities and results, which are presented in greater detail in the following chapters, which have been contributed by the individual researchers in charge of the various aspects of the project under study. Coal Sources, Material Procurement, and Sample Preparation Most of the studies performed during 1972 were done on coal from two sources: the Old Ben Mine #22 in Illinois, and the Bruceton Mine in the Pittsburgh seam of Pennsylvania, which may be considered typical of coal sources of economic importance in the Midwestern and Eastern part of the U.S. These two mines have proven to be reliable suppliers of coal material for our research. We have been able to establish good working relations with their personnel and feel that we can continue to count on their cooperation and help.

Jan 1, 1972

By B. B. Broms

Embankment piles are common in the Scandinavian countries (Kjellman, 1940) and in Southeast Asia as support of fills, light structures, bridge abutments and deep excavations (Eide, 1968) as described in the following. Untreated timber piles are often used for light structures and shallow fills when the ground water level is high since they are inexpensive and readily available. When the applied loads are relatively high precast concrete piles and steel piles are preferred. DESIGN CONSIDERATIONS Embankment piles carry the load from a fill or a struc-ture either through skin friction along the sides of the piles (Fig. 1a) or through a precast concrete slab or through pile caps at the top of the piles (Fig. 1b). When the load is carried by skin friction it is often economical to use small diameter timber piles because of the large surface area (Asplund, 1939). For precast concrete or steel piles concrete caps are used to transfer the load to the piles due to the relatively high capacity of the piles since the skin friction resistance alone is not sufficient to transfer the load to the piles.

Jan 1, 2010

By W. McMahon

Following the Sago Mine accident, the Mine Safety and Health Administration (MSHA) asked the U.S. Army Engineer Research and Development Center to study several possible methane explosion scenarios in the Sago coal mine. The study used a 1-ft resolution map of the mine to produce a 3-dimensional (3-D) model of a portion of the mine, including the sealed area where the explosion occurred. An advanced 3-D computational fluid dynamics (CFD) code was used to calculate the explosion pressures within the sealed area, on the mine seals, and in nearby regions of the mine. Based on the best available information on methane concentrations and assumptions on homogeneity and on layering and mix composition, three separate initial conditions of methane-air concentrations and location were studied. This paper discusses the CFD modeling technique, the results of the calculations, the challenges of conducting this type of modeling, and the advantages and limitations of CFD modeling of accident investigations of mine explosions.

Jan 1, 2009

By R. O. Suominen, P. A. Taskinen, K. R. Lilius, A. T. Jokilaakso

Chalcopyrite concentrate was flash-oxidised in a laminar-flow furnace in oxygen-nitrogen atmospheres that ranged in composition from N2 to N2 + 50 vol% O2. Gas pre-heating temperatures were 500-1100 degrees C and four particle-size fractions were studied: 28-38, 38-44, 44-62 and 62-74 micrometres. The effect of the residence time of the particles on sulphur removal was studied in the range 0.1-0.35 s. Scanning-electron microscopy combined with energy-dispersive analysis and back-scattered electron analysis was used to determine the morphology and mineralogy of the reacted particles. Total desulphurisation was achieved under the most oxidising conditions. Particles were observed to undergo fragmentation during oxidation, the violence of this depending on the iron and sulphur contents and the original particle-size fraction. The melting and/or reaction stages of the particles under different conditions were studied in powder samples. Polished sections were examined to follow the development of porosity and the mineralogy of the particles. A model for the fragmentation process is described

Jul 1, 1991

By C. Slotta, F. Charlier, P. Blomen

"Within the energy concept of the German government, the operating time of nuclear power plants was initially extended from about 8 to 14 years. It is planned, however, that every power plant will gradually be decommissioned until 2025 and that simultaneously the amount of renewable energies will successively be expanded. According to the political state, nuclear energy is a discontinued model. Looking at the global energy market, though, an obviously opposed development can be observed. At the moment, 443 nuclear power plants are running worldwide and further 62 facilities are being built. These about 500 nuclear power stations have to be supplied with nuclear fuel right now and in the future. The present paper will describe the worldwide use of nuclear energy, the extraction of the nuclear fuel uranium and in detail the available and predicted resources of uranium. The conclusion of the paper is the statement that uranium as nuclear fuel is no scarce resource but sufficiently available."

Jan 1, 2011

The Physiographical Features of the Region The Middleback; Range proper, from the Iron Duke in the south to the Iron Prince in the north, extends in a meridional direction for 21 miles, but may well be taken to embrace also the Iron Knob and Iron Monarch prominences so that the total length of the Range is 37 miles.Although no great altitudes are reached, the slopes of the high country are steep and the Range stands out prominently above the peneplaned surface of upper Eyre Peninsula. The Range is built up of sub-parallel ridges at some places, and its continuity is interrupted by transverse breaks or gaps resulting from normal stream erosion and corrosion during earlier periods when precipitation was heavier and streams were more active. Traces of high-level gravels remain on the flanks of Kimba Gap. A former mature stream on the western side of the Range has had its lower reaches blocked by sand and the old stream channel has been converted into an eiongated basin of internal drainage. The sand dunes in this area appear to be practically stationary at present, being fixed by mallee vegetation. Their trend is west-northwest.The relief of the Range is regarded as having been determined primarily by meridional strike faulting and selective silification of some of the beds. Dip faulting on the Iron Duchess leases has produced subsidiary features only.The Rocks of the Region: In order that some of the points made in the discussion of the genesis of the ore bodies may be appreciated it is necessary to consider the stratigraphical succession and the igneous types represented. This classification may be...

Jan 1, 1949

By Richard S. Gaps

In 1983 the U.S. Bureau of Mines conducted a mineral survey of the Golden Valley Wilderness Study Area (WSA), CDCA-170. The 29,887 acre WSA, located in the western Mojave Desert near Ridgecrest, California, is underlain by pre-Tertiary plutonic rocks and volcanic and sedimentary rocks ranging in age from Miocene (?) or Lower Pliocene (?) through Pleistocene and Recent. No mines were operating in the WSA in 1983, nor is any mineral production known to have come from the WSA. Two mining claim blocks, portions of which are within the WSA, and seven isolated prospects, four inside the USA, were examined and sampled. No mineral resources were identified. Widespread propylitic alteration, with localized argillic and alunitic alteration, occurs along the southern boundary of the study area. Samples from claims and prospects within the altered zones are anomalous in gold, silver and arsenic, and some contain antimony, tungsten and mercury, indicating gold resources may exist. Alluvial sample results suggest recent claims in the northwest corner of the study area may also have gold resources. Portions of the study area are within the Randsburg Known Geothermal Resource Area while other segments are considered prospectively valuable for oil and gas and for sodium.

Jan 1, 1985

By Lyda W. Hersloff

An environmental monitoring program was established to assess the baseline of parameters which may be impacted by a research and development hydraulic borehole mining operation. During the baseline program, two aquifers were identified at the borehole site with the overlying sand aquifer being distinct from the ore sand aquifer on the basis of radiological parameters. The direction of flow of groundwater was determined to be north 19° west at a rate of 1.82 feet per year. Tests to determine the effect of backfilling the boreholes indicated that using overburden from the open pit mining operation would not significantly increase the radiological consti¬tuents of the ore sand aquifer. Mining measurements of the- radon flux from the borehole indicated that the actual release rate of 0.035 pCi/sec was several orders of magnitude less than the calculated estimate by the Environmental Protection Agency. Finally, a gamma survey conducted at the site indicated that the terrestrial component of background radiation was consistent with that in areas near uranium deposits. The methodology used as well as the supporting data are given in this report.

Jan 1, 1981

By Daniel G. DiCanio

This report describes a computer-based model for estimating the tangible costs of injuries and deaths from work-related accidents in underground coal mines. The study undertook to identify and quantify the elements of accident costs, including field visits to coal mines, insurance carriers, and public agencies. The mathematical models developed for each tangible element of accident cost are presented in Volume I of the report. A listing of the computer programs which comprise the model and instructions for using the programs are presented in Volume II. Statistical distributions of mining family characteristics, data on 95 miners killed in underground accidents, and other basic data used to develop the model are presented in Volume III. Application of the model to a data base of 9,286 accidents which occured in underground bituminous coal mines during 1974 yielded a total of $56,900,000 in tangible costs to industry, mining families, and public agencies. Loss of income to the families of miners injured or killed in these accidents accounted for 47 percent of the total.

Jan 1, 1976

By E. E. De Beer

This paper describes a method for the determination of the settlement of an individual H-bearing pile, based on the results of CPT-tests. As implied by the nature of the problem, no analysis performed on one pile can be regarded as generally valid for a whole piling foundation project because, even on one site, the pile behaviour varies from one pile to another. Consequently, no precise mathematical analysis has been established; the proposed procedure represents a simple model for the determination of the probable settlement behaviour of an H-pile under a compressive load. Prior to the settlement computations, the rupture load and the resistance distribution along the pile have to be determined. Since the method for the determination of the H-pile bearing capacity from the results of CPT tests has been described elsewhere (de Beer, 1971, 72; de Beer et al., 1982; Arbed, 1985), no details will be given in this paper. The proposed method is valid for both uniform and non-uniform H-piles. The computed results have been satisfactorely compared to the static loading tests performed on different types of piles in clayey and sandy soils during an ECSC research program on H-bearing piles (1983-1987).

Jan 1, 1987

By Fidelis T. Suorineni

Rapid drifting enables quicker access to orebodies, higher production rates and a resultant reduction in production cost. The Mining Innovation, Rehabilitation and Applied Research Corporation (MIRARCO) funded by the Canadian Mining Industry Research Organization (CAMIRO) has developed a methodology for safe rapid drift development within the underground metalliferrous mining industry in Canada According to industry survey, about 36% of drift development cycle time is spent on support installation. MIRARCO has developed a methodology for safe rapid drift development based on minimizing time spent on support installation. The methodology includes a critical review of the rockmass classification systems, examination of current support practices in the mining industry and civil tunneling, review of rapid drift development practice in South Africa, introduction of risk hazard procedures to account for material property variability and the development of a WIZARD as a quick decision-making tool for the implementation of the procedures. A comprehensive field data collection procedure was put in place and data collected from various mines to verify and calibrate the support selection rationale. The findings of the research programme resulted in the development of an improved rockmass classification system and showed that construction effects have drastic influence on support levels but is often not accounted for in assessing support levels. Stress effects and structurally controlled failures are the other important factors to take into account in rapid drift development. Three support classes were established for safe rapid drift development as No Systematic Support, Light Support and Strong Support. The support levels took into account cost, rate of installation and safety based on compatibility with ground characteristics. This paper describes the methodology for safe rapid drifting within the underground metalliferrous mining industry in Canada and highlights the key issues and major drivers behind their continued development at the Geomechanics Research Centre within MIRARCO.

May 1, 2004