Search Documents

By Kevin Whipkey

How is Improvement Being Achieved ? Section Equipment ?Mine Layout/Projections ? Work Schedule ? Maintenance ? Management

Jan 1, 2005

By D. Bogunovic

The U.S. coal mining industry consumes a significant amount of energy, primarily diesel fuel and electricity. The continuous global increase in energy demand, high energy prices, and environmental issues related to carbon dioxide emission represent a substantial challenge for the mining industry. This paper presents a result of research work on development of an integrated data environment system for analysis and control of energy consumption in a surface coal mine. A case study on an operating surface coal mine is carried out to demonstrate the practical application of the developed system. The research work presented here may be used by mining professionals to help provide the answers to the crucial questions of when, where, and how much energy is being used. This developed system represents a framework for efficient management of energy consumption. Key words: surface mining, coal, energy consumption, Information System.

Jan 1, 2009

By M. V. Swain, N. Bristow, R. D. Dukino

During mining, crushing and handling the size of iron ore lumps decreases. Key factors in determining the amount and size of fines that are produced are the mechanical properties of the ore. In a continuation of earlier work on the same ores the mechanical properties of three Australian iron ores from Yandi, Koolan and Mt. Whaleback were determined. In particular, fracture toughness was investigated in greater detail by examining its relationship to crack length using the compact tension test. The elastic modulus and strength of the ores were also determined in flexure and compression. The results were interpreted using Weibull statistics, enabling the ores to be ranked according to strength and elastic modulus. These results, together with data on the mechanical response of the ores to stress and observations concerning the effect of mineralogy on cracking, provide a coherent understanding of the mechanisms involved when the ores fracture

Jun 18, 1905

By R. Barthel, O. Nitzsche, J. Pateiro Fernández, T. Cramer

The Hong Gai coal field in northeast Vietnam has been the main coal mining area of Vietnam for more than 150 years. Anthracite coal is produced from several open pit and underground mines situated close to the UNESCO world natural heritage site Ha Long Bay. The mining-induced environmental impacts such as dust emissions, acid mine drainage, and visual impairments due to waste dumps resulted in severe conflicts of interests regarding future land use and the protection of the world natural heritage site Ha Long Bay. Within the RAME project (Research Association Mining and Environment in Vietnam), Brenk Systemplanung is contributing to an improved environmental and sustainable planning in Vietnam's mining industry and the reduction of environmental impacts on Ha Long Bay by developing suitable and sustainable technology and planning measures (e.g. for dump construction/rehabilitation, predictive modelling, and/or monitoring) for Vietnam's leading coal producer.

Jan 1, 2011

By M. A. Oskouei

Draglines are the main energy consumers in strip mines. Given the growing cost of energy and environmental concerns, it is important to properly understand dragline energy efficiency. The goal of current research at Missouri University of Science & Technology is to account for operator practice and operating conditions in modeling dragline energy efficiency. This paper presents preliminary correlation analysis and a framework for stochastic modeling of dragline energy efficiency. Thirteen operating parameters (including cycle times, payload, swing angle, and height of dump pile), operator working schedules, operating conditions, and drag, hoist, and swing energies were monitored for an 85 yd3 dragline. Operator effects were examined by two-sample t-tests. The relation between the parameters and energy consumption were assessed by correlation analysis and a stochastic modeling framework has been proposed for dragline energy efficiency. The results show that operator effects are significant (p< 0.05) and energy efficiency is correlated with operating parameters. The completed model will help the coal mines better predict energy consumption, with uncertainty, for different operating conditions.

Feb 27, 2013

By Dakota D. Faulkner

Cable bolts have been very effective in mine ground control. Non-tensioned and tensioned cable bolts are now used for both primary and supplemental bolting (Suder, 2001; Mirabile, 2010). In the United States, cable bolts are typically installed in either 1 or 1-3/8 in. (25 or 35 mm) diameter drill holes and, if point anchored only, are utilized with 4 - 5 equivalent feet (1.2 - 1.5 m) of resin. Cable bolts can be tensioned by various methods such as using an expansion shell mounted on the cable or post-tensioned with a hydraulic cable tensioning unit. In recent years there has been a desire to completely encapsulate the cable bolt for corrosion protection. Fully encapsulating a cable bolt with traditional resins can be very difficult. Keystone Mining Services, LLC (KMS) and Jennmar Corporation have developed a new cable bolt that can be fully encapsulated during installation or post-installation with polyurethane (PUR). The Fully-Grouted Cable Bolt (FGCB)* is equipped with a special head that allows the injection of PUR up through the cable bolt head and cable strands, completely encapsulating the cable and filling the drill hole. Although the FGCB was initially developed to fully encapsulate the cable for corrosion protection, it was also found that by modifying the cable bolt head and injection pressure, PUR could be injected into cracks and fissures of the strata to stabilize the roof. This paper details the development of this system and three underground applications under different ground conditions.

Jan 1, 2012

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 S. Sarac

In this study, graphical and mathematical methods used to determine operating points in single or multiple fan ventilation systems are summarized. The problem is mathematically formulized for parallel connected fans in which analytical solutions are not possible. For n number of parallel connected fans, a non-linear equation system that consists of n number of non-linear equation sis derived. The Newton-Raphson method, which is a numerical analysis method, is adapted to solve this non-linear equation system and the solution steps are given as an algorithm. A computer program based on this algorithm is written and its applicability is proved.

Jan 1, 2000

By G. W. Thomas

Jan 1, 1967

By R P. Callaghan

Underground production from the low grade copper orebodies at Mount Lyell in recent years has involved surface subsidence of open cut areas. Relevant structural and lithological features of the geological environment are described. The highly mechanised underground mining system involves sublevel caving and sublevel open stoping with associated hanging wall cave. Monitoring of subsidence and caving has been made by regular visual inspection and measurement of crack development, and by surface profile surveys. These simple techniques have proved adequate in assuring management that ground movement is proceeding normally and safely.

Jan 1, 1980

To develop more accurate means of measuring low ventilating air velocities in underground mines to facilitate compliance with ventilation standards. The Approach: A commercially available vane anemometer which produces an electrical, rather than a mechanical, output was coupled to electronic circuitry to produce the Bureau&apos;s Digital Low Velocity Anemometer (see photo). [ ] How It Works: The experimental instrument has a vane anemometer head which produces an electrical output signal with a frequency directly proportional to the rotating speed of the vane anemometer shaft. The commercially available ABBIRKO FLOWMASTER anemometer head was used in this instrument. In the signal conditioning circuits the electrical signal from the anemometer is converted into pulses, which are counted during either 3-second or 1-minute intervals, depending on the position of the operator&apos;s control switch. (Readout is either "instantaneous" or averaged for a period of one minute.) The number of pulses counted is then translated (integrated and divided by a constant) in the logic circuits to get average speed. Average air velocity in feet per minute is displayed in illuminated digits. (See simplified diagram of circuitry.)

Jan 1, 1975

By N. S. Yet

This paper shall present the design and construction of bored pile and diaphragm wall for the proposed MHA complex in Singapore. The work was carried out by L&M Foundation Specialist Pte Ltd and PWD Consultants Pte Ltd was the consultant for this project. A brief description of the project is first presented to illustrate the scope and scale of the work involved, which includes the construction of bored piles and diaphragm walls and installation of steel stanchions in the bored piles. This is followed by a description of the methodology used to analyse and design the wall and bored piles. As both towers in this project are supported on bored piled foundation and are constructed by top down construction method, the analysis of the wall has taken into consideration the sequence of work phase by phase and this was carried out by means of a commercial finite element program called CRISP. Modelling of the problem will be briefly described and the findings from the numerical analysis will be presented. This is followed by a description of the structural and geotechnical design aspects of bored piles. The paper shall then describe the difficulties encountered for this project and solution used to solve the problem. The subsoil condition will be described with special mention on the encounter of very strong granitic rock at depth above the maximum excavation level of the basement at certain locations, hence necessitating the drilling of rock for a considerable depth for both bored piles and diaphragm wall. At this juncture, the construction method used to drill through the rock will be briefly described. For construction of bored piles, penetration of rock was carried out by chiselling or drilling using reverse circulation rigs. For construction of diaphragm wall, it requires the employment of Bauer hard rock cutter which uses cutting wheels fitted with roller bits and are capable of excavating into granitic rock of compressive strengths more than 100 MPa.

Jan 1, 2000

The New Zealand Steel Ironsand Slurry Pipeline was successfully commissioned in February 1986. The project includes 18 km of high pressure, polyurethane lined buried pipe. McConnell Dowell Constructors Limited has developed a coupling which has allowed this pipeline to be fully welded. The design and development of the coupling and its application on this project is discussed.

Jan 1, 1986

By D. van der Veen

Mining companies and contractors are looking at Wirtgen Surface Miners to provide flexibility at their operations. Wirtgen Surface Miners have been used in the surface mining industry for over fifteen years. The principle behind the Wirtgen Miner is a rotating drum equipped with tungsten carbide tipped cutting tools that excavates and sizes the material. The drum helix augurs the mined material to the center of the drum where it is loaded onto the primary conveyor belt. From there the material is conveyed to the discharge belt and into a truck bed. The cutting drum is located in the center of the machine, near the center of gravity. This permits the machine to cut hard materials as the entire machine weight is converted into cutting forces. Conventional mining practices are process, equipment, and labor intensive. Furthermore, strict environmental requirements pertaining to noise levels, dust pollution, and blasting, near buildings or urban areas, limit the application of conventional methods. Mining/ Construction contractors are using Wirtgen Miners in various limestone excavation projects, such as highway expansion projects, and new roads in housing developments. Mining companies in the industrial minerals and coal industry are using Wirtgen Miners to load directly onto trucks, eliminating the rehandling process and ultimately, primary crushers.

Jan 1, 2002

By M. Doggett

All 231 Canadian primary gold mines that produced from 1946 to 2004 were analyzed with respect to their production and economic characteristics. Trend analysis revealed that the average annual capacity of Canadian gold mines, as measured by ore processed or gold produced, has increased over time. Conversely, the average grade of gold mines has decreased over time. The distribution of gold output is highly uneven: for example, the 22 giant mines producing more than 100 t (metric tonnes) of gold account for 62% of total output. Small mines producing less than 10 t Au account for 54% of total mines, but less than 4% of total gold. Each historical mine in the database was evaluated on the basis of a set of economic and technical assumptions to determine if it would be economic to develop today. Based on the net present value using an 8% discount rate, only 103 of the 231 mines were determined to be economic. About 80% of the uneconomic mines had less than 10 t of contained gold, and 63% had less than 5 t. It is concluded that these small mines would not be viable today due to a combination of real capital cost increases, and more stringent permitting and environmental regulations. The implication is that future gold supply in Canada will hinge on the discovery and development of a new generation of larger mines. Given that only one giant mine has been discovered in the past 20 years, it seems likely that gold output will decrease in the future.

Jan 1, 2007

By Lees M. G, Vitnell B. W

The post-war need to increase coal production promoted an intensive drilling campaign. Ineffectiveness in core recovery inclined the coal industry towards percussion drilling rather than diamond drilling. The Joint Coal Board, recognising the greater potential of core drilling, has actively encouraged improvement in techniques and equipment. One outstanding need was a barrel which, over and above other improvements being achieved, would permit recovered core to be examined before it had been subjected to the increased fragmentation and displacement which to date has been inevitable except in core which has been drilled in solid sticks û as New South Wales coal rarely can be drilled. In conjunction with Triefus Pty Ltd a barrel with a split inner tube has now been evolved, as a result of which, core can be more accurately logged, division in to lengths for analysis more aptly made, any core loss more reasonably allocated to appropriate plies, and a greater percentage of core recovered û of the order 95 per cent and more. The one half of the split inner tube is lifted from the other and the logging completed before the core is disturbed.

Jan 1, 1957

By G. van Aswegen

The geometry and morphology of a set of low-angle fractures around a stope in a deep Witwatersrand gold mine are explained in terms of extension fractures forming under variable conditions of stress. Primary extension fractures (E1) form some distance ahead of an advancing stope along the s1, s2 plane. With stope advance, a couple of these fractures end up in a stress regime conducive to transpressional shear and a secondary set of extension fractures(E2) is formed at a high angle to the primary fractures. i.e. at a low angle to the stope. As the E2 fractures are undermined, they migrate into a stress regime of transtensional shear and a third set of extension fractures (E3) may develop between E2 fractures. These have sigmoidal shapes, being parallel to the E2 fractures at the E2 discontinuity where s3 is negative, and curved through the un-fractured rock between E2 fractures where s3 is positive at the instant of fracturing. The fractures all display fractographic features characteristic of dynamic extension failure with striae indicative of the direction of rupture propagation and the local, instantaneous orientation of s1.

Jan 1, 2012

By W. A. Burns

Vertical flow is an important mechanism in many petroleum reservoirs. Yet no adequate method has heretofore been proposed for determining the in-situ vertical permeability in a reasonable length of time. Core measurements of vertical permeability do not necessarily represent effective in-situ values. Cores may be representative of only localized pockets of high or low permeability, and total reliance on cores might cause one to overlook the presence of vertical fractures altogether. Conventional single-well tests, interference tests, and pulse tests commonly are used to determine horizontal transmissibility, khh/u, but generally are not designed to measure vertical trans-missibility or other groups containing vertical permeability, ku. A new well test described here provides a measure of in-situ vertical permeability as well as the previously measurable horizontal permeability. This "vertical test" determines the vertical diffusivity, kv/gcu, and horizontal transmissibility, khd1/u (where dl is the length of injection or production perforations). The test is basically a short-term interference or pulse test normally lasting less than a day. Conventional down-hole equipment is used between two isolated sets of perforations in the same well, as shown in Fig. 1. A "layer-cake" description of a reservoir can be obtained by running two or more vertical tests in the same well, each over different vertical intervals. Each test can be analyzed for the effective vertical and horizontal properties of the interval tested. In addition, a vertical well test can determine the effective- ness of a shale barrier or tight zone by testing across it. Field use to date of vertical testing has confirmed its utility in reservoir description. Mathematical Basis Interpretation of vertical tests for ku and kh is based on comparison of measured pressure response with computer-generated response. Pressure behavior during a vertical test in a homogeneous, anisotropic, infinite-acting reservoir (infinite in radial extent and bounded in both directions vertically) is given by the diffusion equation for slightly compressible fluids with negligible gravity effects.l A schematic diagram of the problem is presented in Fig. 2, and an analytic solution, based on the image

Jan 1, 1970

By David D. Rabb

A report on location, sampling, assays, mineral examination, amenability leach tests, and evaluation of certain mine dumps in Mohave County, Arizona. Extractions of greater than 30 percent of the gold and silver were achieved during simulated heap leaching of selected mine dump material. Consumption of reagents was relatively low and results suggest leaching of prepared heaps is technically viable and could be economically attractive.

Jan 1, 1980

By Wolfgang G. Brunner

The center of Berlin is currently a huge jobsite, where international architects, designers, consultants, construction and ground engineers as well as investors take on the challenge of the biggest and probably most complicated projects in terms of soil conditions in Europe. The Berlin sand is generally suitable for foundation measures, but can be very tricky in deep excavation pits below the high ground water level. The reason for this is its uniform grading, medium dense stratification and lack of cohesion. The requirements for these deep pits are: - measurements in the range of up to 120 000 m2 per pit - depths up to 19 m below ground water level - lack of dense horizontal geological layers - no permission for lowering ground water levels - toughest ever European competition in construction. Sheet pile walls, sheet piles set into cut - off walls, secant pile walls, diaphragm walls, all with tie backs under high water pressure, are used as retaining sytems. The pits are closed at the bottom against water either by under water concrete, deep lying grouted cut - offs or high lying jet - grouted cut - off slabs. The huge dimensions of these excavation pits are a new challenge for ground engineers, and new technology had to solve the upcoming problems and resulted in new experience.

Jan 1, 1999