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By Elizabeth Cruz

The paper point out innovative energy management techniques that lead to energy recovery and uses it back in the process as heat, mechanical work or power with a consequent impact on operating cost and operating cost and operation cost and a reduction in the overall enviroment impact.

Sep 14, 2009

A shortage of technical skills in all areas of the mining industry is being experienced worldwide. This has significant consequences for design, operations, productivity and safety and, therefore, needs to be seriously addressed, both in the short and longer term. It is therefore both a strategic and a tactical issue. Importantly, however, since mining is a long-term business, the shortage of skills must be dealt with from a strategic point of view to ensure the supply of the necessary skills for future mining. This paper will deal specifically with the provision of high level technical skills, that is, university graduates in mining engineering, and the outlook for the institutions that are currently producing such graduates.

Jan 1, 2009

By William R. Yernberg

A conference on coalbed and coal mine methane was held March 27 and 28, 2000, in Denver, CO. The conference, organized by the Strategic Resource Institute, was attended by leaders in the coal mining and gas energy industry. The conference focused on the recovery of methane from coal beds as an energy resource and the removal and utilization of coal-mine methane (CMM) related to underground coal mining. The two-day conference discussed methane resources around the world, methods of recovery, methane markets, underground coal mining, health and safety issues and environmental issues related to methane. The consensus among the presenters is that the future looks promising for coal bed methane (CBM) and CMM.

Jan 1, 2000

By Peter N. Holtham, Geoffrey J. Lyman, The University of Queensland, Matthew S. Brennan, Vijay Subramanian, Rui X. Rong

"The cyclone would have a claim to be the commonest, least understood and most abused piece of mineral processing equipment available for study by researchers. It has certainly generated its fair share of publications – 1,000 in the last 60 years would be a fair estimate. However this remarkable degree of interest and scale of investigation is not reflected in our understanding of how they work; cyclones are still installed inappropriately and run poorly, which suggests that there are still things to learn about this deceptively simple process.In mineral processing there are two broad classes of cyclone: the hydrocyclone, used in classification, thickening and dewatering, and the dense medium cyclone, used for concentration by density. Although rarely studied together, the laws of physics presumably apply equally to both and so it seems that there would be interesting things to learn by considering them as a single class of device. The good news is that in recent years there have been spectacular advances in the computational and measurement tools available to study these devices, including computational fluid dynamics (CFD), tomography, and laser doppler anemometry (LDA), and some good progress has been made in an understanding of the fundamental principles involved.The JKMRC has made many experimental studies of hydrocyclones and DM cyclones, leading to useful empirical models. However some recent CFD and tomographic work, in association with work of other institutions, has thrown important light on the workings of these processes. Progress has also been made in novel designs of cyclone to achieve improved separating efficiency, based on an attack on the subprocesses believed to contribute to inefficient operation. This paper describes the work to date.Modelling of the dense medium and classifying cyclone was conducted using the Fluent computational fluid dynamics code. Three phase simulations of the dense medium application (air/water/medium) showed appropriate medium segregation effects but over-predicted the level of segregation compared to segregation measured by gamma-ray tomography. This is believed to be because the basic Algebraic Slip mixture model in Fluent does not model any back-mixing of the dispersed phase due to turbulence."

Jan 1, 2003

By J. Torma-Krajewski, C. Hipes

Although many mining companies apply ergonomic principles, it is usually done either informally and/or reactively. An example of an informal approach is replacing worn equipment (such as seats) with models that have ergonomic features. Another example is modifying a task to eliminate safety hazards. Such approaches reduce risk-factor exposures that can lead to musculoskeletal disorders (MSDs). A reactive approach is followed when modifying a task/ equipment after an MSD occurs. However, neither of these approaches involves a systematic method of proactively applying ergonomic principles to actually prevent injuries or illnesses. This paper discusses how Vulcan Materials Company applied ergonomic principles and implemented interventions to reduce risk-factor exposures.

By Emma Arakelova

An increase in concentration of a Zn-containing volatile complex for synthesis of ZnO films was investigated when processing their target by ultraviolet radiation emitted by mercury lamp. The experiments were carried out using a flow-type quartz reactor. ZnO tableted target was preliminarily irradiated during 2 to 7 hours. H2O2 (98%) vapor at 25Pa passed through the reactor with ZnO target at 373K. As substrate material, five subsequent quartz cylinders were used at 423K. The experiment lasts 4 hours. H2O2 decomposition on ZnO surface was accompanied by formation of a Zn-containing volatile complex which passed in gas phase and decomposed on the substrates with isolation of final ZnO. The concentration of the Zn-containing volatile complex (N) in gas phase increases with UV pre-irradiation time (t) (without irradiation N = 1.05 1011 particles/cm3; after t=2 hours, N = 5.19 1011 particles/cm3, after t=4 hours, N = 9.95 1011 particles/cm3; after t=7 hours, N = 1.86 1012 particles/cm3.

Jan 1, 2006

By Mohammed Sakr

The use of helical piles for permanent foundation applications has become a practical and feasible alternative to the traditional cast-in-place concrete or driven steel piles. Research and development, installation equipment and manufacturing improvements in the helical piling industry have led to this trend. Moreover helical piles are typically smaller in size and weigh less than traditional piles, and require relatively smaller equipment and therefore it is a cost effective option. The latter is a very attractive feature for foundations installed in remote sites across Alaska. This paper presents full-scale pile load test results of helical piles and driven steel pipe piles installed in a site located in Anchorage, Alaska. Four full-scale pile load tests were carried out including two axial compression and two uplift load tests. Both helical piles and driven steel pipe piles were installed and tested at the same site under similar conditions to provide a direct comparison. The results of the full-scale load tests indicate the superior performance of helical piles compared to driven steel pipe piles. This paper describes the pile installation and test setup, presents the test data, and discusses the results.

Jan 1, 2009

By John F. McCoy

The United States Bureau of Mines (USBM) awarded a contract to Foster-Miller Associates, Inc. (FMA) to develop guidelines for designing, constructing, stocking and maintaining rescue chambers in underground mines. This report develops information and recommendations which could be used by a mine operator who desired to install a rescue chamber. Volume I covers the following major areas: atmospheric life support, configuration and construction, chamber location, power and lighting, equipment and supplies, communications, and psychological aspects and training. Volume II contains the following appendices: History of Barricading, Chamber Pressurization Considerations, Diffusional Infiltration of Gas, Compressed Air Storage, Location Examples, and Psychological Aspects.

Jan 1, 1983

By Terry L. Muldoon

This report describes development and demonstration of an upgraded stench fire warning system for underground wines. Current systems, which have been used since before 1920, release an ethyl mercaptan mixture into the mines' compressed and/or ventilation air during emergencies. Miners, when smelling ethyl mercaptan, evacuate the mine according to predetermined plans. These systems, while simple, have problems with safety and reliability. The upgraded system overcomes these problems. The system uses a different stench agent, is less toxic, less nauseating, and less corrosive than ethyl mercaptan. These combined with the feature of thiophane not reacting with iron oxides, makes the upgraded system safer and more reliable. The system also uses a combination of two simple principles: a standpipe with pressure balancing to provide a constant head, and a sized orifice to control the rate of release of the stench agent. This system enables the mine to release the agent for a longer period which provides better coverage and to ensure that miners will not be exposed to potentially toxic concentrations of the stench agent. The system is easy to operate, requiring only the turning of two 1/4-turn ball valves. The upgraded system has been successfully tested during two evacuation drills at an underground uranium mine. Using three injectors (one on the compressed air line and one on each of two intake air shafts), the system exhibited significant improvements in warning times over the mine's existing system. This report provides a detailed description of the system design and its demonstrated performance in two mine demonstrations.

Jan 1, 1981

By Edward Capillon

THE problem of scrap is probably of greater importance inn the production of gold, silver and other precious metal alloys than is the case for base metals and alloys. Remelting of gold and silver scrap in the shop is always a costly process because it involves losses by oxidation of the base metals in the alloy with a consequent increase in the percentage of precious metal. This is most marked in the case of alloys containing the low-boiling and easily oxidized metals zinc and cadmium. Since it is. not generally feasible to assay every shop remelt it follows that the possibilities of lost values are large. So-called rolled gold and silver plate is made by soldering or welding the precious metal alloys onto base, metal. Such plate when defective must be sent to the refinery to recover the gold and silver values, thereby involving additional expense in the form of refining charges. It is obvious therefore that gold and silver alloy scrap is an important item in manufacturing cost and must be reduced to a minimum. The amount of scrap resulting from poor metal will depend on a number of factors in the manufacturing operations, not least among which is the melting and casting practice. The notes which follow are a summary of experiments performed at various times to determine what variables in melting and casting are influential in the production of sound alloys.

Jan 1, 1930

By V. E. Edlund

As part of a research program for recovering alumina from domestic nonbauxitic resources, the Bureau of Mines investigated a lime-sinter, caustic leach technology for anorthosite. This report discusses the unit operations--feed preparation, sintering, and leaching. Acceptable pellets for the bench-scale sintering studies were prepared from mixtures of minus 200-mesh anorthosite and limestone using water alone as the pelletizing agent. Heating pellets at 1,270° to 1,360° C for periods of 0.5 to 2 hr, followed by a 15-min soaking period at 700° C and cooling to room temperature, produced a sinter that dusted to more than 90 pct minus 65 mesh. The weight ratio of limestone to anorthnsite was critical in producing sinter exhibiting good dusting and leaching characteristics. A ratio of 2.0 was optimum for the bulk samples of anorthosite and limestone used in this research. Leach solutions from lower ratio sinters were unstable; gelation became progressively more severe with higher ratio sinters. Leaching the dusted sinter with 10-pct Na2CO3 at 60° C extracted 85 to 90 pct of the alumina in a product solution containing about 50 g/l A1203. Leach residue in contact with pregnant solution tended to set up as a rigid gel as a result of cementation, comp action, and gelation. The presence of a calcium-sodium zeolite [(Cn,Na2)6?(Al2Si04)12?27-3OH20] in the ungelled residues seemed to be the main difference between gelled and ungelled residues.

Jan 1, 1982

By Stephen Hodgson, Ken Brouwer

September 2005, Northern Dynasty Mines announced the discovery of a new, high-grade deposit at its Pebble project in southwest Alaska. The product of insightful geological investigation, Pebble East, as it is now known, is quickly growing into one of the most significant copper deposits in the world. Preliminary analysis shows it could reduce the U.S. copper supply deficit by a third. The new deposit has also altered Northern Dynasty’s view of how Pebble should be developed. This article describes the Pebble project as it is currently understood and outlines the work planned for the next several years.

Jan 1, 2007

By J. J. Dekker

Controlling noise has proven difficult in mining, and noise-induced hearing loss (NIHL) remains common. In 2008, a South African Mine Health and Safety Council study focused on small- to medium-sized mines in relation to the milestones set by the industry to prevent NIHL. An evaluation of the compliance of ten diamond, sand, aggregate and Ready mix concrete mines and production sites with standards, legislation and best practice guidelines relating to NIHL prevention was conducted, using a noise compliance audit tool. The findings indicated that all mines surveyed had poor compliance with the international standards, compliance with International Standards Organization standards being the poorest. There was a clear distinction between the small and the medium-sized mines in their compliance with local standards and legislation (ranging from 14 per cent to 66 per cent). The areas of best compliance were audiology and medical examinations. The lower-than-expected compliance was largely attributable to shortcomings in hearing conservation programmes for occupational noise. Initiation of remedial practices in the small- to medium-scale mining sector to facilitate improvements in NIHL prevention and compliance with standards and legislation is recommended. Keywords Hearing conservation, small-to-medium mines.

Jan 1, 2011

By Srinivasulu Tadisetty

The productivity and safety of Indian longwall operations are insignificant because of complex geomechanical conditions. Therefore, the continuous monitoring and forecasting of abnormalities is imperative. Authors developed an innovative real time system and implemented in one of the Indian longwall mines. The real time system was successfully acquired data from underground chock shields and classified the behaviour in real time as per the standard norms. Furthermore, it forecasted the abnormal behaviour of chock shields promptly. The management was implemented appropriate precautionary measures based on real time forecast. Subsequently, the longwall operations were successfully completed with enhanced productivity and safety. This paper discuss the impact of the innovative system on productivity of experimental longwall mine.

Jan 1, 2006

By Kara A. Teacoach

Current regulations for fire suppression systems in underground coal mines to protect conveyor belt installations have been in place since the Coal Mine Health and Safety Act of 1969 was enacted. Over time, the coal conveyer equipment being used and ventilation conditions underground have changed significantly, particularly the width of the conveyor belts and the use of belt air at the face. The effect of these new conditions on the effectiveness of suppression systems during a fire is not known. The National Institute of Occupational Safety and Health (NIOSH) conducted a study to evaluate the effect of air velocity, water sprinkler activation temperature, and a limited water application time on the effectiveness of water sprinkler fire suppression systems to extinguish large-scale conveyor belt fires. The fire tests were conducted using both new and used 1.8-m-wide, fire-resistant rubber belt that met the Mine Safety and Health Administration (MSHA) flame resistant requirement specified in Title 30, Code of Federal Regulations, part 18, section 18.65 (also known as the 2G test). Tests were conducted using standard response sprinklers with activation temperatures of 68 °C and 141 °C at air velocities of 0.5 and 5.1 m/s. Two tests were conducted at both air velocities for each sprinkler activation temperature, one using a new belt and one with a used belt. The results showed that the suppression system was able to suppress the fires in ten minutes to the point that a miner could extinguish it with a fire hose. However, in several of the tests, the fire reestablished itself a few minutes after the sprinkler water supply was cut off and quickly grew out of control. This report discusses the large scale experimental configuration, the installation specifications of the fire suppression system, and the results and conclusions regarding the effect of air velocity, sprinkler activation temperature, and limited water application on the suppression system performance.

Jan 1, 2010

By A. C. Fieldner

"INTRODUCTION In a previous report3 prepared for the American Gas Association, the influence of washing coal on coke properties and on gas and by-product yields was discussed on the basis of answers to questionnaires sent to coke-oven superintendents and a review of the literature on the subject. This review indicated that the elimination of free impurities by cleaning coal improved coke quality by (a) reducing ash and sulphur, (b) decreasing clinker trouble in burning the coke, (c) diminishing cross fractures in the coke, resulting in greater resistance to breakage on handling, and less small coke and breeze, and (d) greater uniformity in chemical composition and physical properties of coke. Washing also reduced the sulphur in coke and gas and increased the yield of gas and by-products per ton of dry coal charged.This paper is supplementary to the previous report and presents some experimental data obtained with Pittsburgh bed coal from Pennsylvania and Mary Lee bed coal from Alabama.ACKNOWLEDGMENTSGrateful acknowledgment is made to F. J. Pfluke, of the Rochester Gas and Electric Cc., of Rochester, N. Y., for the plant test data on screened lump and washed coal; and to Ray W. Arms, Manager of the Coal Cleaning Department, of Roberts & Schaefer Co., of Chicago, for the data on effect of air cleaning."

May 1, 1931

By José Cayetano

El presente trabajo plantea un proceso para minimizar el contenido de bismuto en las celdas de electrorefinación, a través de la adición de carbonato de bario a la solución electrolito, de forma que el bismuto soluble presente en fase líquida, se precipite sobre la superficie del precipitado insoluble de BaSO4, bajo una coprecipitación por adsorción e intercambio debido al equilibrio dinámico entre el precipitado y la solución de electrolito conteniendo al bismuto. En este sentido, se reduce la presencia del bismuto en el electrolito de cobre en un 75%, adicionalmente se tiene la disminución del contenido de plomo en un 96%, de estaño en 48% y de plata en un 18% aproximadamente.

Oct 21, 2015

By S. Addie

In the early 1990’s the British Columbia (Canada) mineral industry frequently discussed the need to participate in, and compromise with, public environmental interests in order to ascertain long-term stability. However, as the decade progressed the mineral industry withdrew from almost all meaningful public participation. As government protected areas policy in the past year has illuminated, there is a continued need for long-term land access stability. This paper historically analyses the public engagement policies of the British Columbian mineral industry while it participated in long-term consensus-based multi-stakeholder land-use planning processes. From this analysis the paper recommends that the mineral industry reengage the public and institute a new working relationship with environmental advocacy groups so as to ensure British Columbia becomes the most sustainable mineral producing jurisdiction in the world.

Jan 1, 2011

By R. H. Sprute

This report describes Bureau of Mines laboratory test results in electrokinetic dewatering and consolidation of metal-mine tailings. Tailings were placed in 0.3-cubic-foot Plexiglass models, and dc potential was applied until dewatering ceased. Time-oriented measurements of water removal, changes in resistivity, and power consumption were recorded during the dewatering process. Dewatered material was tested for moisture content and density. Equipment and procedures were developed to optimize the method for unclassified mill tailings from a particular mine in the Coeur d'Alene, Idaho, district. Results indicate the method to be highly effective in dewatering and consolidating this material.

Jan 1, 1974

By G. M. Martinez

The Bureau of Mines has investigated methods for the recovery of byproduct heavy minerals from sand and gravel operations in Oregon and Washington. These heavy minerals are not currently recovered except for gold in a few areas. The recovery of byproduct heavy minerals would provide a domestic source of minerals presently imported, and a more efficient use of domestic resources would be accomplished. Samples from more than 40 locations were treated by gravity separation to yield heavy mineral concentrates (black sands). Magnetite, ilmenite, zircon, rutile, chromite, platinum-group minerals, radioactive minerals and gold were identified in the concentrates. Individual zircon, ilmenite, chromite; magnetite, and gold products were recovered from selected concentrates by low-and high-intensity magnetic, high-tension, and heavy-medium separation techniques. The recovery for the individual mineral products ranged from 67 to 95 pct.

Jan 1, 1981