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By Kenneth C. Ko

An engineering investigation was carried out on the technical and economic feasibility of implementing flexible liner/backpacking support systems In an advancing tailgate longwall mine. The system for a model mine consists of a circular tube constructed of liner plates and flyash backpacking. Flyash is pneumatically stowed into the tailgate. Small amounts of cement may be mixed to improve the support capability of the fill In difficult local ground conditions. Water is added inside the nozzle immediately prior to spraying. Results of theoretical analyses and a field test show that the designed system is technically feasible, can be cost-competitive, provides more stable ground conditions, and can Increase productivity and coal recovery, when compared with existing retreat longwall systems. In certain mine layouts, the new system can reduce the direct mining costs by a significant amount. The system would be particularly applicable to deeper coal beds with bad ground conditions.

Jan 1, 1980

By Wijnand Dalmijn, Hans de Ruiter

Experience over the past eight years has proven that partnership and cooperation in mineral engineering education is essential to maintain programs in this field. At this moment the joint European Mineral Masters Engineering Course (EMMEC) has three programs in the areas of mining, minerals engineering and geotechnical/environmental engineering, offered by combinations of nine universities in seven European countries. About 25 companies are associated with the universities in the Federation of European Mineral Programs (FEMP) which coordinates these activities. The EMMEC has applied for recognition under the newly launched EU “Erasmus Mundus” program in which the EU makes 280 million Euro available for bursaries for non-European students and scholars.

Jan 1, 2005

There are many ways to classify structural slurry wall elements, but the DFI committee chooses to limit these descriptions to three functional requirements, namely: design function, plan configuration and type of panel reinforcement. (See Figure 1 in Part IV for panel classification). Slurry walls can function as: 1. Curvilinear or linear elements for temporary and/or permanent structures to resist lateral forces transferred from the ground, water, earthquakes and various surcharge loads. 2. Load bearing elements in various plan shapes to resist vertical forces. 3. Combination Elements to resist combined forces under conditions 1 and/or 2. For example, elliptical shafts with various openings for tunnels and conduits have been commonly used for deep excavations.

Jan 1, 2005

By Eric R. Bauer

The U.S. Bureau of Mines, in cooperation with a southwestern Pennsylvania coal mining company, BethEnergy Inc., Mine No. 60, Eighty-Four, PA, recently assessed the feasibility of using pre driven recovery rooms (open entry recovery) when longwall mining to increase the productivity of the coal extraction process. Two recovery entries, one 200 ft long and another 600 ft long, were supplementally supported with bolts, channels, and wire mesh, and either fly ash-cement piers or fiber cribs, then mined into by the longwall face. The recovery entries showed little deterioration as the supports provided adequate resistance to the front abutment loading. Compared with conventional recovery methods, the fullface recovery room allowed for panel extraction to be completed nearly 17 days faster and to reduce face equipment move time by 1-1/2 days. The potential productivity increase accompanying recovery rooms is greater than the cost of supporting a fullface recovery room. The fullface recovery room provided over 18 additional production days and the opportunity to mine nearly 68,400 st of coal per year per panel mined.

Jan 1, 1989

By John J. Sammarco

The mining industry has the highest average annual fatality rate among major U.S. industries. To address this, the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory (PRL), is conducting major research programs to reduce the hazard exposure of miners. One of the recently concluded programs at PRL developed the enabling technology for remote-controlled mining. An application involves the manual process of extracting and hauling coal where operators, in the tight confines of a mine, can be struck or caught by mobile machinery. The approach to remedy this problem uses a guidance system on the continuous haulage equipment so that it follows the continuous mining machine that extracts coal. This, in essence, involves sensor-based docking of the machines. Sensors functioning in the hostile mine environment of dust, methane gas, and water play the key role. Computer analysis of the mining machine's movements and empirical machine characterizations established operating requirements and spatial limitations to ensure proper loading of coal into the haulage equipment. These data served in the selection of a guidance sensor. Technologies such as scanning laser systems and ultrasonic sensors have frequently been used in other applications, but were found unacceptable. However, a near-infrared sensor employing active targets met the requirements. The sensor has a nominal 75b conical field of view and a range from 0.1 to 18.0 m. For the single-target mode, nominal range accuracy was 4.3% at a distance of 3.65 m. Correction algorithms were generated, which reduced the error to 0.6%. Airborne dust testing showed less than an additional0.8% accuracy (worst case) degradation at dust levels up to 15 mg/m3. Using four targets, the nominal range accuracy was 0.4% without correction algorithms. Analysis of dynamic testing of a continuous miner and haulage showed that accuracy was maintained and total target loss did not occur. A guidance system for the haulage system to follow the mining machine does not exist commercially. Such a system can reduce fatalities, injuries, and exposure to dust and noise.

Jan 11, 1998

Safe underground mine backfilling with hydraulic fill requires efficient fill drainage and stable fill retaining walls or bulkheads. If any or both the above two requirements are not satisfied, such a backfilling operation creates unsafe conditions and may lead to backfill retaining wall failures. Mine backfill retaining wall failures are always associated with economic losses, fatalities and interruption to mine production. Mining industry wants to either reduce or eliminate these fill retaining wall failures. The fill retaining wall failures could be effectively avoided through the use of fibre reinforced shotcrete fill retaining walls and engineered drainage systems through the retaining walls. This paper presents the experience of the author in developing, implementing, and monitoring several hundred fibre reinforced shotcrete fill retaining walls at a mine in Australia with the highest safety standard. The details on the mine backfill drainage system and fibre reinforced shotcrete fill retaining wall designs are also presented.

May 1, 2007

The purpose of the contract was to develop an improved coal mine dust sampler whose electrical-to-mechanical energy conversion efficiency would be superior to that of the presently available equipment. The electrical to (pressure) X (volume) conversion efficiency directly affects the size and weight of the air samplers. At least half of the mass of present equipment is composed of the rechargeable batteries. Any increase in efficiency will allow this mass to be reduced or the flow rote to be increased.

Jan 1, 1974

By Paul M. Ambrose

Overall the domestic abrasives industry had one of its best years in 1965. Production and value of all commodities increased over that of 1964 which also was a good year. Production of tripoli that was down in the previous year rebounded and production from two new mines was reported. Plant capacities for production of silicon carbide and fused crude aluminum oxide and production from plants in the United States and Canada increased, but demand was high and yearend stocks were less than at the end of 1964. Foreign Trade.-Increases in value of most imports of abrasive materials in 1965 were offset by a decrease in the value of imported industrial diamond. Production of fused aluminum oxide and silicon car-bide in the United States and Canada and imports of these commodities into the United States increased, but combined exports of finished grain of these materials was virtually unchanged from the previous year.

Jan 1, 1966

As part of its research and development activities concerning coal mine operational/emergency communications sys terns, the Bureau of Mines commissioned several contractors to conduct electromagnetic (EM) noise studies and measurements that would aid the development of improved coal mine operational/emergency communications systems. The bulk of the noise studies and measurements were conducted in 1971. The Pittsburgh Mining and Safety Research Center (PMSRC) inherited the responsibility for monitoring the electromagnetic noise activities by mid-to-late 1971, and initiated a review and evaluation of the current and planned electromagnetic noise work. Arthur D. Little, Inc., (ADL) was asked by PMSRC to assist it in performing this review and evaluation by placing stronger emphasis on certain tasks of existing Contract No. H0122026. This technical memorandum report presents the findings, conclusions, and recommendations of our review and evaluation of the electromagnetic noise measurements of the five contractors we were asked to examine. Our review and evaluation effort included meetings and telephone discussions with technical staff of each contractor; serving as Technical Discussion Leader of a "Contractor's Round Table Meeting on EM Noise, Surface and Subsurface, Operating and Non-Operating Mines" called by the Bureau of Mines; examination and discussion of contractor reports and relevant open literature; sample verification calculations; and the documentation of our findings, conclusions, and recommendations by this report.

Jan 1, 1972

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Jan 1, 1938

By Arun .. J. Basu

The paper introduces Intelligent Air Management (IAM) as the core activity of M&I Group of Companies (M&I) for providing a total solution to any air management problems for mining and mineral processing operations implementing a comprehensive systems approach through a world-wide network of strategic alliance partners and in-house engineering team and manufacturing facilities in Mississauga, Ontario, Canada. Recommendations for energy-efficient ventilation in a vibration and noise free environment are made with the patented and innovative solutions supported by extensive computational fluid dynamics (CFD) studies. The solution scope extends from an intelligent and integrated exhaust silencer to a complete ventilation sys-tem solution including inlet and outlet control design and ducting for diffusers and silencers.

Apr 1, 2005

By N. M. Safaya

Moderate to acute deficiency of plant available phosphorus is very common in western coal mine spoils and topsoils. Although some of the spoils are known to contain seemingly adequate amounts of total phosphorus, the plant available phosphorus is so low that it constitutes a serious plant growth limiting factor in the mined lands. For the revegetation of these spoils, the use of species, varieties and ecotypes exhibiting greater efficiency for P uptake and utilization, or conversely, lesser susceptibility to P deficiency would be highly desirable. To identify such plants, quick and adequate methods of screening germplasm should he available. In the present growth chamber study several plant species were screened using continuous flow culture and spoil culture systems to provide information on their relative susceptibility. In flow cultures, P was maintained at 0.25, 2.5, and 25 moles; while in spoil cultures it was applied at 0, 25, and 75µg/g to a P-deficient spoil. Phosphorus deficiency symptoms appeared in alfalfa cultivars, birdsfoot trefoil, emerald crownvetch and yellow sweetclover within 7-10 days upon transfer of their seedlings to U.25 or 2.5 µM P solutions. Burning bush and Russian thistle, found abundantly as pioneering species on mine spoils, showed no deficiency symptoms; their shoot dry matter yield in the 0.25µM P treatment was 24% and 36%, respectively of their maximum yield obtained with 25 µM P. However, the percent increase in the dry matter yield of legumes with 0.25 µM P ranged from 7-13% over their maximum yield. With the increase in solution P concentration, the root dry weight ratio in the legumes increased from an average of 0.22 to 0.43, while in the weeds from 0.14 to 0.30. The low susceptibility of Russian thistle to P deficiency was also demonstrated in the spoil culture experiment. Legumes showed greater response to P-fertilization on the spoil than did the two weeds. With increasing concentrations of P in the solution, the root weight ratio of all the species decreased. At 25 µM P, weeds invested only 14% of their total dry matter yield in the root fraction, where as legumes and grasses invested as much as 24% and 33% respectively. Weedy species averaged higher P concentrations than the legumes and grasses. The mean P concentrations of alfalfa cultivars were the lowest among legumes. In general, P concentrations increased with the increase in P supply. In the flow culture system, P supply increased the Ca levels of legumes. The mean Mn concentrations were highest in the weedy species. The increases in P supply decreased Zn levels in all of the species. File effects of P fertilization on the tissue concentrations of Mn and Zn in spoil culture were similar to that of flow culture system. From this preliminary study, it may be concluded that the continuous flow culture system is efficient in rapid screening of a large number of species under controlled conditions for their efficiency in adapting to mineral stresses.

Jan 1, 1982

By W. W. Roepke

The Bureau of Mines has developed an interactive computer program that enables mine operators and others to identify the effect of cut-ting system changes on relative dustiness at the face. The program, which simultaneously evaluates machine parameters, coal seam parame-ters, and operator-controllable parameters, was developed for use on any microcomputer using BASIC programming language. The program allows the user to change one or more of the cutting system parameters at a time to see how these changes affect relative dustiness. A complete program listing and flowchart are included along with operating in-structions and sample outputs. An example showing how to use the program is also included.

Jan 1, 1985

By L. Nahai

THE OUTPUT ff the mineral industry in 1964 in both non-Communist and Communist Europe showed an upward trend for most countries in keeping with the higher index of overall industrial production. Comparable indexes of mineral industry production for non-Communist and Communist Europe (including the U.S.S.R. in Asia) are not available, primarily because the U.S.S.R. does not report details of its industrial production by industrial sectors. However, available data both in the form of index numbers on production published by the United Nations and based on data as reported to the United Nations by the various countries, and actual production data for selected major commodities published by the various European countries reflect generally expanded output by both the extractive sector and the processing sector of the mineral industry in most of the 26 nations of Europe.

Jan 1, 1966

By L. Bircumshaw

Paper written on project work carried out in partial fulfilment of BSc (Eng) (Chemical) degree This paper details the formulation of a mathematical model for the simulation of a primary bioleach reactor, with specific reference to the leaching of pyrite. The model is based on the direct reaction mechanism, where the leaching of pyrite is said to occur via a two-step process. The process involves the formation of ferrous?iron through the chemical leaching of pyrite and subsequent bacterial oxidation of ferrous-iron back into ferric-iron. At steady state the rate of chemical leaching and bacterial oxidation are linked by the ratio of ferrous-iron to ferric-iron in solution. The extent of conversion of pyrite in the reactor system is described using the segregated flow model, with the exit age distribution of the solid phase being described by the Tanks-in-Series model. The final phase in model formulation involves the inclusion of steady state material balances on the bacteria and fluid phase components. The model is compared to pilot plant data and laboratory data for two different types of pyrite concentrates, with simulation results showing that the model is in good agreement with the data. Author key words: Bioleaching; pyrite; primary reactor; modeling; segregated-flow model; tanks-in series model.

Jan 1, 2006

By C. L. Schneider, C. O. Gomes, R. P. King, J. A. Finch, D. Lin

Discussion is presented by Prof. King and Dr. Schneider of the paper by Lin, Gomez and Finch published in Trans.IMM C, vol.104, 1995, p.C155-C161. They conclude that the correction procedures used for simulated observations of simulated capped spheres are not reliable when applied to mineralogical data and that their relative ranking should not be extrapolated to other situations. Properly regularised solutions obtained with the use of appropriate kernels can be safely used for routine mineral liberation work and can be calibrated accurately against real mineralogical samples in the laboratory

Jun 19, 1905

By I Mason, A Wellington, J Hargreaves

Many people are familiar with the use of marine echo sounders which are used by fishermen to monitor water depth and locate schools of fish. Similar technology has recently been used in some West Australian mines to provide detailed maps of ore contacts and other geological structures. Whilst drillhole intersections provide details of the location of a contact at a point, echo sounding can be used to obtain a continuous profile of the contact. A series of profiles together with drillhole intersection data can be used to build a more accurate geological model than can be inferred from drillhole intersections alone. The benefits of this are more complete ore extraction, less dilution and the ability to make more informed financial decisions. This paper presents a case history which demonstrates the successful application of the technology.

Jan 1, 2000

By Roger L. Baer

Marine disposal of mill tailings has been practiced worldwide for over a century. However, only recently have the environmental effects of marine disposal been systematically studied. Some early attempts at marine disposal of tailings resulted in adverse impacts to marine life. However, recent advances in tailings disposal methods have included the introduction of engineered submarine tailings discharge systems, advanced environmental assessment and monitoring methods, and oceanographic modeling systems. Successful submarine tailings disposal (STD) has occurred at several mines. The U.S. Bureau of Mines (BOM) has undertaken studies of the disposal of mining and milling wastes in the marine environment. The BOM Alaska Field Operations Center, Juneau, initiated a review of the technology, regulations, and economic aspects of STD. The review illuminated the need for organization of literature on the subject, therefore the Bureau compiled this extensive bibliography on marine disposal of mill tailings. The bibliography presented here contains 1483 references and is also available through diskette in the Word Perfects format. A review of the references indicates that literature on submarine disposal inadequately covers the subject. The majority of the references listed only peripherally relate to the subject. Published literature on the engineering and environmental aspects of STD is severely limited.

Jan 1, 2011

By Carl-John Grävare

This paper deals with some of the systems and equipment that are being developed and/or are in use in Scandinavia. The main subject is the development of loading tests on the piles using monitoring equipment. This paper also describes ground improvement using lime-cement columns, expander body piles and steel core piles.

Jan 1, 2000

By J. A. Cox

The Ashanti mine is located within the Lower Proterozoic Birimian of Ghana, and covers a concession of 474 square kilometres at its Obuasi operations which comprise large scale underground, surface and tailings treatment facilities. The mine had operated for a century at the end of 1997 and had produced nearly 25 million ounces of gold, a significant proportion of which came from the underground operations. This paper covers the strategy under which exploration for both surface and underground mineral resources was instrumental in enabling the expansion programme to go ahead together with the methodologies and results that have developed in the exploration area over the last five years. Within capital expenditure constraints, the objective on surface is to replace oxide depletion with a secondary objective of discovering new sulphides in areas other than the main trend. In the underground, the exploration strategy is directed at replacement of both underground and surface sulphide depletion, minimising finding costs and assisting the development of long lead time infrastructure. The exploration application describes the methodologies in use for both surface and underground exploration that have been developed in recent years in conjunction with a description of a major review conducted in 1995/96 of the exploration database using an integrated approach, geochemistry, geophysics, remote sensing and structural geology. A revisit of soil geochemical data in particular, and modification of exploration methodology led to the success in finding relatively significant new oxides in 1997.

Jan 1, 1999