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The fundamental features of the Cable Belt Conveyor are described. It consists of independent wire ropes which take the transmission load, and a special reinforced rubber belt which acts 'only as carrier of material. The first cable belt installation in Scotland is described briefly.A general description of this type of conveyor is followed by details of the rubber belt construction and the method of joining sections of belt. The drive unit, the tensioning arrangements and the power requirements are outlined.Applications of the cable belt conveyor are 'dealt with and its advantages summarized.INTRODUCTIONThe cable belt conveyor, as its name implies is a conveyor composed of steel wire ropes and a rubber belt, in which the ropes serve as transmission members, and the belt merely as a carrier of materials.Over the years it has been the ambition of engineers connected with the belt conveyor industry to develop a conveyor that would use the high tensile strength of wire ropes to transmit the stresses involved in the driving of large capacity belt conveyors. Different lines of approach have been adopted in the United States of America and in Britain. In the United States the method adopted was to introduce a large number of flexible steel cables into the rubber belt itself, in the form of a closely packed layer arranged across the full width of the belt. These small cables are packed in a nylon filled duck envelope which is incorporated in the rubber belt. This is commonly known as the steel corded conveyor belt. In Britain, a Scottish firm developed a rubber belt conveyor in which full advantage was taken of the high tensile features of wire rope, without embodying or moulding the wire rope into the rubber belt, so that the two wire ropes and the rubber...

Jan 1, 1957

By W. P. Johnstone

The computer assisted generation of geological models to represent the geometry of, and grade distribution within, orebodies is a rapidly growing area of the geological profession. Such models are increasingly used as a necessary starting point in determining the mineability of mineral deposits in terms of practical mine design and economic considerations. The transition from traditional techniques such as field or underground mapping and the manual calculation of grade and tonnage estimates, as well as related activities such as the interpolation of cross-sections, the use of stereographic projections, core logging and hand contouring, to computerized applications, is by no means complete. In fact, many geological professionals deliberately avoid the use of computer simulations based on the perception that the resulting models are simplistic and that their construction is not founded on sound geological principles. The purpose of this paper is to assess current thinking on this topic by considering; (a) an overview of advances in the drafting of geological maps, (b) the theoretical basis for multi-dimensional geological modelling, (c) the case for combining traditional and modern techniques, and (d) the benefits to the mining value chain.

Jan 1, 2003

By H. M. Coggin

The study summarizes the state of the art in rock mechanics, open pit and underground mining, leaching, geology, metallurgy and financial analysis Conceptual design of pit slope caving technique and analyses explore concepts for the exploitation of ore grade remnants in the walls and bottoms of open pit mines and the potential economics of the adaptations Several coded sites were examined for future studies where the feasibility of the method may be demonstrated. An extensive bibliography has been developed

Jan 1, 1977

By A. Ochieng

Solids suspension influences the quality of mixing and energy requirement in a solid-liquid system, both of which determine the efficiency of industrial processes such as nickel precipitation. Nickel solids concentration distribution in a stirred tank was investigated using computational fluid dynamics (CFD) and experimental methods. The concentration distribution of the nickel solids was compared with that of sand and glass. The laser Doppler velocimetry (LDV) method was used to measure the velocity field for the liquid-only system and an optical technique was employed to determine the axial solids concentration distribution. Regions of in homogeneity in the tank were identified. It was found that, for a given solids loading, the solids concentration distribution depended on both particle size and particle size distribution. High solids loadings were investigated and a difference in the concentration distribution pattern was obtained with nickel, flint glass and sand particles. The CFD simulation results highlighted problems that could be associated with some conventional experimental methods of determining solids concentration distribution in a stirred tank. Keywords: nickel; CFD; simulation; mixing; solids suspension.

Jan 1, 2010

The #3 Shaft at Brunswick Mine, Bathurst, New Brunswick, Canada, intersects a soft graphite zone just below the 3400 Level. Ground movement within this zone causes the concrete liner of the shaft to be deflected towards the shaft?s interior, affecting the steel framework of the conveyance. In some areas, the clearance between the cage and the liner has been reduced to less than 2 cm, which is a concern. An innovative surface-mounted extensometer was designed in 2008 to monitor potential movements of the shaft?s liner. Four such novel extensometers were installed in the shaft for the surveillance of a particularly critical 3.0m by 5.5m area. This article describes the approach taken to instrument the shaft, the principle of the new extensometer, as well as the performance of the instrumentation following its installation.

May 1, 2009

By B. M. Loftus

An investigation into the use of impinging stream (jet) reactors for the leaching of a free milling ore produced an increase in gold recovery by 10% while decreasing leaching time by up to 90%.Tests on refractory ores demonstrate no apparent improvement in recovery. However, leaching kinetics are dramatically increased when these ores are subjected to jet reaction prior to agitation.

Jan 1, 1997

The aim of this research was to study the absorption characteristics of thermally dried fine coal from South African collieries. After milling to ?150 µm and pressure filtration, the samples were subjected to either air drying or thermal drying at 150°C. The samples were then put into a climate box at 28°C and at three different relative humidity levels, namely 30, 60 and 94 per cent. It was found that the equilibrium moisture content of thermally dried coal at a specific relative humidity was lower than that of air dried coal. The relationship between the equilibrium moisture content and relative humidity is described by 1 ? RH = exp (-KTMen). There was no relationship between the volatile matter content and equilibrium moisture content, but there was an increase in the equilibrium moisture content of the coal with an increase in mineral content. The moisture uptake rate increased with an increase in temperature and a decrease in particle size. A model is discussed that fitted the experimental data and gave a good prediction for changes in the conditions. There was no evidence of greater moisture absorption by thermally dried coal. Keywords: Fine coal, thermal drying, drainage, South Africa, drying

Jan 1, 2002

By R. J. Durrheim

The seismicity of the Witwatersrand Basin and Bushveld Complex has been analysed, revealing significant differences in source and damage mechanisms. A comparison of mining taking place at similar depths and extraction ratios indicates that the seismic energy release rate is considerably lower in the Bushveld Complex. Technologies introduced in the past decade to manage the risk of rockbursting are reviewed and assessed. These include geophysical methods to detect hazardous structures ahead of mining, new mining layouts and support systems, and the mechanization of in-stope processes. Despite important differences in geology, in situ stress, mining layouts and methods, there are many opportunities for the reciprocal transfer of knowledge, experience and technology between the gold and platinum mining sectors to improve the management of the rockburst risk.

Jan 1, 2005

By W. W. Adams

Increased employment and a lower accident-frequency rate were the outstanding features of the metal- and nonmetal-mining4 industries of the United States in 1939 compared with 1933, according to reports furnished by individual mining companies to the Bureau of Vines, United States Department of the Interior. Except for 1937, the reports for 1939 showed gains both in number of employees and number of mar -hours worked over all years since 1929. The accident-frequency rate per million man-hours of exposure to mining hazards was lower than in any year since 1925. Reports for 1939 revealed a total of 111,909 men employed in and about mines, an increase of inure than 8 percent over 1931 The total volume of labor performed at all mires was slightly more than 299 million plan-hours, an increase of mare than 10 percent over 1938. As these gains suggest, the average employee had a longer period of work in 1939, the increase amounting to r workdays per employee.

Jan 1, 1941

By Jürgen F. Brune, Liming Yuan, Alex C. Smith

To provide insights and assistances for the optimization of ventilation systems for U. S. under-ground coal mines facing both methane control and spontaneous combustion issues, a computational fluid dynamics (CFD) study is being conducted to investigate the effect of the ventilation scheme on the prevention of spontaneous combustion in longwall gob areas. This report focuses on the flow patterns within the gob under three different ventilation systems; one-entry and two-entry bleederless systems as well as a three-entry bleeder system. The gas flow in the caved gob area is simulated as a laminar flow through porous media while the gas flow in ventilation airways is simulated as a fully developed turbulent flow. The air flow patterns are visualized using flow path lines. Air velocity contours and vector data are also obtained. The possible location of critical velocity zones where the gob is most liable to spontaneous heating is discussed.

By R. Mier

The metals and minerals mining industry has evolved dramatically from the earliest objects ever made out of native copper circa 9,000 BC to the modern developments we see today. To better appreciate past developments and to get a sense of where the industry is heading, a brief overview of mayor industry highlights over the last 100 years will be presented, followed by a discussion on potential global scenarios and by a review on mayor industry trends.

Feb 27, 2013

By G K. Jorkenson

Blast designs to cast a percentage of overlying waste rock off coal seams differ greatly from conventional blast designs for surface coal mines. Today, blasting engineers can benefit from computer simulations to test various blast designs and reduce cost and time spent on the old trial-and-error method.

Jan 1, 1989

By Hanlong Liu

The construction process and load-bearing behaviors of Cast-in-place Concrete Thin-wall Pipe Piles are analyzed based on its application on Yan-Tong Expressway project. The low strain test, static load test and field excavation are also carried out. It can be concluded that the new type of pile is convenient to construction with high bearing capacity and reliable quality, which has great potential in practical engineering.

Jan 1, 2006

By Y. C. Liu

Both the habit plane of martensite and the orientation relationship between the matrix and martensite platelets of different habit planes have been investigated in binary titanium alloys with molybdenum, chromium, and iron. The effect of the mode of deformation on the martensite habit plane was studied. A micrograph of an exposed mar-tensite platelet is presented. IN the study of martensitic transformation in Ti-Mn alloys,' two martensite habit planes—{334), and {344)8—were reported. The {334), habit was also observed in unalloyed titanium upon transformation,' although there is disagreement with respect to the exact indices. The other habit plane, {344),, has not been reported in martensitic transformation in any other alloys. The present investigation was made to determine whether other binary titanium alloys with P-stabil-izing elements would exhibit a crystallography of transformation similar to that of Ti-Mn alloys. Furthermore, since martensite platelets can be induced by deformation under certain conditions, it was of interest to investigate whether the mode of deformation, compressive or tensile, would influence the formation of martensite platelets on a specific plane in an alloy system which possesses two martensite habit planes. Experimental Procedure The material used for the preparation of the binary alloys of iodide titanium with molybdenum, chromium, and iron had the following purities: 99.99 pct iodide titanium, 99.9 pct molybdenum, 99.423 pct chromium, and 99.9 pct iron. The compositions of alloys listed in this paper are in nominal weight percentage. All specimens used were prepared and treated according to the procedure described in reference 1, unless stated. For the subzero temperature treat,ment the following experimental schedule was followed. After specimens had undergone the grain-growth treatment, they were quenched into an ice-water bath and were then metallographically examined. In specimens of higher alloy content, no martensitic transformation was observed. In those in which mar-tensitic transformation did occur, only specimens in which the martensite platelets existed as fine needles in localized regions were used. All specimens were reannealed 17 hr at 1200°C, quenched into ice water. and the capsule was broken. They were held in the ice water for from 5 to 10 sec, then transferred to a liquid-argon bath. This stepped quenching procedure was found to be more efficient than direct quenching into liquid argon. In the latter case, as soon as the hot specimen was immersed in the liquid argon, a protective, insulating layer of argon gas formed, and the specimen continued to glow vividly in the bath for some time. In the study of the habit behavior of martensite produced by deformation, specimens were deformed at room temperature either by compression, tension, or rolling. Martensite habit planes were determined by the two-surface analysis procedure described in reference 1. A stereographic net of 153/4 in. diam was used throughout the investigation. The method for determining the orlentation relationship between martensite and the matrix follows that used by Greninger and Troiano.' A diamond-polishing table with its auxiliaries was used in order

Jan 1, 1957

By S. Weiss, E. Espinoza

The El Sauzal gold-silver deposit is a high-sulfidation, epithermal precious-metals deposit hosted by an east-dipping sequence of dacitic and rhyolitic pyroclastic and debris-flow units of probable Oligocene age. Total gold production since startup in late 2004 is approximately 450,000 oz. of gold. Above the sulfide boundary gold is mainly disseminated as small grains interstitial to alunite, kaolinite and quartz. The majority of the ore is found in quartz-alunite-kaolinite altered rock that mantles tabular to irregular silicic cores of vuggy, residual quartz ±kaolinite ±dickite. Grade domains are modelled as subhorizontal to east and southeast-dipping. Higher-grade domains cut across alteration zones and also coincide with transitions from vuggy quartz to quartz-alunite-kaolinite. The highest grades are commonly found marginal to vuggy quartz in transitional, hematite-rich quartz-kaolinite and quartz-alunite-kaolinite rock.

Jan 1, 2007

The National Institute for Occupational Safety and Health (NIOSH) conducted a monitoring field study to optimize the rib control plan in a room-and-pillar coal mine. The study mine is located in the Central Appalachia coal basin. Two monitoring sites were selected at different sections in the study mine. The selected sites have different overburden depths and geologies. The instrumentation plans at study sites include borehole pressure cells installed at various depths in studied pillars, rib and roof extensometers and load cells mounted on number of the rib bolts. The instrumentation results and observed geology for one of the study sites showed great potential for optimizing the rib bolt plan at that section of the mine. Therefore, a rib support optimization study was followed using numerical modeling technique. A calibrated threedimensional model was developed using the instrumentation results of the optimization section. The calibrated model was used to determine the optimum rib support for expected overburden depths and rib heights. Baseline rib bolt patterns were assumed for the optimization study. Additional rib bolts, above and beyond the baseline bolting parameters, were outlined and identified as solutions to contain the rib fracturing identified by the modeling results.

Jul 28, 2020

By F. S. Kendorski

This report presents the results of a search for viable-self-drilling roof bolt concepts, detailed development, design, and manufacture of such bolts that drill their own holes, and testing in the laboratory and in the field in two different coal mines of three self-drilling roof bolts. Three new types of bolts were designed and tested, which drill their own holes and then anchor in continuous operation. These were a spring-actuated mechanical expansion shell, a slot and wedge, and a self-contained resin anchor bolt. Such bolts when fully developed for mine use would allow safer and remote installation of ground support and increase productivity. Recommendations are given for further work to improve drilling and anchorage performance.

Jan 1, 1979

This study estimates costs of producing bituminous coal and lignite by strip-mining methods in 12 hypothetical mines. Basic costs are developed by geographic area, rank of coal, and output capacity. Seam thickness and depth and type of overburden are considered typical for the area in which the hypothetical mine would be located. The cost analyses are based on the use of new equipment, the prevailing union wage scales, and the payment of all miscellaneous costs including royalties, contributions to the miners' welfare fund, and license and permit fees. All model mines are considered to have a life span of 20 years. Capital costs of bituminous strip mines with a capacity of 1 million tons per year range from $12.7 million in the Appalachian region to $16.0 million in the Interior province. The corresponding selling price, assuming a discounted cash flow return of 12 percent on investment, is $5.40 and $6.95 per ton, respectively. For bituminous coal strip mines producing 3 million tons annually, a capital investment of $24.9 million will render a selling price of, $3.46 per ton in the Interior province, whereas a similar mine in the Appalachian region requires a capital investment of $28.0 million to produce coal selling for $4.01 per ton. Subbituminous strip mines of 5 million tons of output per year range in capital costs from $28.7 million in the Southwest to $13.9 million in Wyoming and Montana. Coal produced in the Southwest would sell for $3.03 per ton, while coal from Wyoming and Montana would sell for $1.83 and $1.64 per ton, respectively. The capital costs for the strip mining of lignite range from $6.4 million for an output capacity of 1 million tons annually to $20.7 million for an annual capacity of 5 million tons. The corresponding selling prices of $3.01 and $2.12 per ton, respectively, Indicate the advantages of a large-capacity strip mine.

Jan 1, 1972

By H. Lawson

The Mine Safety and Health Administration (MSHA) issued Program Information Bulletin P09-03in April of 2008, providing formal guidance on using programs that model the redistribution of stress during underground mining of coal. A key part of this guidance is visual observation and mapping of ground conditions. If a correlation between ground conditions and model output can be established, the model is considered to be verified, and can be used to guide mine design in similar ground. A simple scale is recommended for ranking observed roof, rib, and floor conditions. This paper discusses optimization and implementation of a ground condition rating scheme in the gateroads of a deep underground longwall coal mine. Roughly 80% of each gateroad length deteriorated in a fairly uniform manner. However, this manner varied between gateroads, as did pillar size. The implementation of a ground condition mapping program, similar to that recommended in PIB 09-03, was successful in characterizing the ground response to mining in gateroads of a longwall coal mine.

Jan 1, 2012

By P. S. B. STEWART

As part of a continuing study of mechanisms of breakage, the grinding at Nairne Pyrites Pty. Ltd. was traced by the addition of barytes and the results compared with parallel small scale laboratory tests. It was confirmed that the same basic mathematical functions described the behaviour of the full scale ball mill as those established in the small scale mill. However, an additional classification function was required to define the behaviour for the rod mill and was evaluated as a function of size from the experimental data. The classification and grinding of the pyrites ore was assessed from steady state size distributions around the circuit.

Jan 1, 1971