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By D. R. Corson

The Bureau of Mines instrumented an operating stope in a deep vein mine to determine the amount of wall closure and the magnitude of loads imposed on a backfilled stope. Hydraulic pressure cells used to monitor pressures in the fill) with bolt closure points to measure vein-wall movement and the procedure for their installation) are described) and the results of the laboratory calibration analysis of the reliability of these cells are given. An attempt to monitor density and moisture changes in the backfill with a nuclear density-moisture device was only partly successful) owing to either deformation of access tubing or relative displacements of the vertical vein walls relative to the emplaced tubes. Data from the instrumentation indicate vein-wall closure in excess of 20 inches and pressures within the fill approaching 600 psi. Analysis) incorporating field data with results of laboratory tests of the compressibility of timber and tests defining the constrained moduli of the fill) points out the limited restraint to vein closure offered by timber sets. Ground movement induced by mining activity could be more effectively con-trolled by the use of densely compacted backfill.

Jan 1, 1967

By Robert W. Decker

This report presents a survey of published novel coal cutting (mining) concepts and a brief discussion of each one. A preliminary evaluation follows which identifies promising concepts, emphasizing reduced dust generation and economic production potentials. The promising concepts are then studied more deeply and evaluated in more detail with recommendations given for further development action. The concepts recommended for further work include: Roan and Pillar Mining: Deep Cutting Continuous Miner Linear Cutting Rotary Head Miner Longwall Mining: Oscillating Continuous Water Jet Miner Deep Cutting Shearer

Jan 1, 1981

By M Ash, P Bellairs

The world class iron ore mines at Mt Whaleback, Tom Price and Paraburdoo located in the Hamersley Province of Western Australia must mine the Mt McRae Shale to obtain high grade ore from the Dales Gorge Member of the Brockman Iron Formation. The Mt McRae Shale contains a Black Pyritic Shale lithology that reacts with Ammonium Nitrate based explosives. This paper provides an overview of the problems associated with mining this reactive rock type as well as the development of a comprehensive procedure to safely and efficiently blast, excavate and dispose of this material.

Jan 1, 1995

By J. G. Wiese

Reagents are added to the flotation process of Merensky Reef ores to achieve specific functions that enable the separation of valuable minerals from gangue minerals on the basis of the difference in their surface properties. However, due to the complexity of the process, the various interactions that occur as well as the incomplete liberation of the ore and range of minerals present, it is difficult to quantify the behaviour of each of the reagents. More specifically, changes made to achieve a particular outcome may have secondary effects that can override the desired effect. If all the effects and interactions can be accounted for, it is possible to manipulate reagent suites and obtain better overall metallurgical performance. This paper discusses the effect of the addition of copper sulphate at different operating points of the recovery of the sulphide minerals. Batch flotation tests indicated that the recovery of chalcopyrite was not affected when operating conditions were varied, whereas pentlandite recovery was strongly affected by the point of reagent addition, and pyrrhotite recovery was enhanced by copper sulphate addition, irrespective of the point of addition, with the extent being dependent on the ore source. Floatable gangue was activated by copper sulphate in the presence of the dithiophosphate collector. Froth stability was also affected by copper sulphate addition.

Jan 1, 2006

By Kai Nielsen

The paper presents the results of several industrial and laboratory blasting, crushing and grinding tests and experiments investigating how blasting can influence the subsequent crushing and grinding operations. The paper also describes how these results can be used in order to optimize the entire comminution process from solid ore to a semifinished or marketable product. Two cases are presented, one looking at the processing of fine grained taconite ore, and the other discussing the processing of raw milling product for cement burning.

Jan 1, 1998

By K. Heindlhofer

Estimates of the "plasticity" of a metal are commonly deduced from three types of test—tensile, torsion and impact. The several results have been more or less at variance, though this disparity has attracted little notice, largely perhaps because they have been expressed in different terms. The discrepancy between the results of the three tests becomes obvious when each is made at a series of low temperatures, for the temperature range within which the "plasticity" of iron largely disappears proves to be very different in the three types of test. The rather abrupt disappearance of "plasticity" of iron within a narrow temperature range cannot be due to any physicochemical change (such as a precipitation) taking place in the material at that time, because the original plasticity is immediately regained when the temperature of the material is brought above the sensitive range. Accordingly this difference in behavior shows that the "plasticity" of a metal depends upon the mode of action of the stresses which produce the deformation, and therefore upon the method of test. Analysis of the stresses leads to the conclusion that the observed plasticity of a metal is determined by the relation between its resistance to rupture by separation and its resistance to shear (slip), on the one hand, and between the effective normal and shearing stresses on the other; and that the relation between the two resistances does not in general remain constant with change of temperature, and may somehow be altered to some extent by the previous treatment of the specimen. This suggests the view that the results of none of the usual mechanical tests are directly comparable even for a single metal tested at a series of temperatures, or for a series of metals at one temperature, because the proportion of the total resistance of the metal to the test contributed by the

Jan 1, 1935

By K. Heindlhofer

Estimates of the "plasticity" of a metal are commonly deduced from three types of test—tensile, torsion and impact. The several results have been more or less at variance, though this disparity has attracted little notice, largely perhaps because they have been expressed in different terms. The discrepancy between the results of the three tests becomes obvious when each is made at a series of low temperatures, for the temperature range within which the "plasticity" of iron largely disappears proves to be very different in the three types of test. The rather abrupt disappearance of "plasticity" of iron within a narrow temperature range cannot be due to any physicochemical change (such as a precipitation) taking place in the material at that time, because the original plasticity is immediately regained when the temperature of the material is brought above the sensitive range. Accordingly this difference in behavior shows that the "plasticity" of a metal depends upon the mode of action of the stresses which produce the deformation, and therefore upon the method of test. Analysis of the stresses leads to the conclusion that the observed plasticity of a metal is determined by the relation between its resistance to rupture by separation and its resistance to shear (slip), on the one hand, and between the effective normal and shearing stresses on the other; and that the relation between the two resistances does not in general remain constant with change of temperature, and may somehow be altered to some extent by the previous treatment of the specimen. This suggests the view that the results of none of the usual mechanical tests are directly comparable even for a single metal tested at a series of temperatures, or for a series of metals at one temperature, because the proportion of the total resistance of the metal to the test contributed by the

Jan 1, 1935

By Malcolm Arnesen

Mineral Resource Management (MRM) is a business concept with the purpose of increasing throughput by management of key process variables to optimize ore utilization. To achieve a MRM process focus there are four principles that need to be applied to the business. In this sense, the paper define these principles and describe how they are applied to the mining business using Thabazimbi iron ore mine as an example. Also the article deals with the generic approach to Mineral Resource Management and the second part with the application and success of MRM at Thabazimbi Iron Ore Mine.

Jul 17, 2000

I was lucky to land a job in the powder business. I was looking for some way to support my wife and first child to be when I saw an ad in the Hercules magazine, “Explosives Engineer” for technical representatives. I answered the ad in hopes that a geologist might find something else to do besides sit oil wells or “doodlebug” for oil. Both of these occupations I had tried and while the money was good the life was a bit erratic. The Army also wasn’t made for a guy who asked too many questions although my two plus years in uniform were interesting and in a few cases fun.

Jan 1, 2004

By H Mali, B Kain-Bückner

Different types of lump iron ore-bearing particles were investigated in terms of their raw material properties depending on their behaviour during reduction. To predict the reduction behaviour different types of lump iron ore and pellet brands were characterised by their mineral abundance, texture and pore size. The image processing software VisuMet was developed to semi-automate the evaluation of photomicrographs from polished sections of lumpy iron particles. The results were compared to the standard reducibility test after ISO 4695. The evaluation of lump iron ores is based on the simulation of the transformation of the different iron minerals due to their sequence of reducibility. The progress of the reduction front is simulated and the result is a degradation curve. Pellets were also investigated due to their different pore size distribution. The results indicate that the pore size influences the reducibility in addition to mineral abundance. The evaluation with VisuMet of the lump iron ore and pellet samples correlates with the reducibility provided by the ISO 4695 test. The determination of the mineral abundance by VisuMet is comparable to common point counting with a correlation coefficient of 99.67 per cent.CITATION:Kain-Bückner, B and Mali, H, 2017. VisuMet – analyses of lumpy iron carriers with image processing, in Proceedings Iron Ore 2017, pp 557–560 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By H. J. Ilgner

The paper reviews the results to date of an integrated research programme currently being conducted by CSIR Mining Technology, aimed at impacting significantly on concentrated mining with face advance rates of up to 20 times faster than presently achieved. Consideration is given to the interplay between innovative technologies for continuous non-explosive mining or rock comminution underground and lateral hydraulic transportation in cross cuts, haulages and eventually hydro hoisting. Novel technologies for underground comminution of reef and development waste and an innovative pumping system suitable for the hydraulic transportation of coarse comminuted rock are reviewed. Emphasis is placed on South African gold mine reef and waste samples comminuted by electric shock wave comminution technology. The innovative TORE® pump system appears to be well suited for the successful hydraulic transportation of rock, produced by electric shock wave comminution, at solids concentrations between 45 % and 67 % by mass.

Jan 1, 1997

By John R. Rhodes

The objective of this project was to investigate the feasibility of analytical techniques potentially capable of determination of Mg, Al, Si, S, Ca and Fe in 1 to 2 mg samples of respirable coal mine dust, in a total analysis time of not more than 10 minutes per sample, using equipment capable of being truck mounted for field-laboratory operation. It was not essential that the technique be non-destructive, but the chosen technique is, and this enables the analysis to be performed directly on the 37 mm diameter membrane filter on which the respirable dust sample is normally collected. The sensitivity requirements are therefore quoted in terms of the units of measurement, µg/cm2. The detection limit (3o of the background criterion) should be 0.5 µg/cm2 or less. The precision should be 5% or better, at concentrations above which the detection limit is not the determining factor.

Jan 1, 1972

By John D. Warne

"INTRODUCTION Initiated as a part of the Bureau of Mines program for development of strategic minerals for national defense, Investigation of the fluorspar deposits of the Northgate area was begun in June 1944 and completed in March l946. Mining Operations were active in the district during most of the period of investigation.The Fluorspar, Fluorine, and Camp Creek mines develop the two more promising vein systems known in the area, the Fluorspar group of claims covering one vein system and the Fluorine and Camp Creek groups the other. Figure 1 shows the location of the properties. The Fluorspar and Fluorine properties were operated (except during the winter months) by the Western Fluorspar Corp. The Camp Creek mine was operated during 1943 and 1944 by Kramer Mines, Inc.The properties were examined April 20 and again November 4 to 12, 1943, by C. R. Wilfley, a Bureau of Mines engineer, who recommended work to determine ore reserves and to serve as a guide for development. Investigations by the Bureau of Mines covered all three properties."

Aug 1, 1947

By W. Stumpf

Mean flow stress analyses from plant mill logs for the conventionally produced hot rolled low carbon steel from the Ispat Iscor Vanderbijlpark strip producing plant, indicated a higher temperature sensitivity than that found for the equivalent SAE 1006strip steel produced in the compact strip plant of Saldanha Steel. This was confirmed quantitatively through detailed hot deformation studies on an as-cast structure as well as on a finer grained condition on the same steel. In the conventionally produced steel, activation energies for hot deformation of 309 kJ.mol-1and 388kJ.mol-1for the two respective starting structures were found, both values extending over the entire normal hot deformation temperature range of 1140 to 900°C. These and other experimentally determined constitutive hot deformation constants were applied to the hot rolling austenite grain size development model used earlier. From this, it is predicted that dynamic recrystallization occurs only in the first two break-down passes at the Vanderbijlpark plant and thereafter static recrystallization occurs after exiting from all of the remaining ten or eleven roughing and finishing passes. This is significantly different from what was predicted earlier for the Saldanha Steel plant with its lesser number of passes where static recrystallization is predicted to occur only in the last three passes. The effects of this process difference and other observed product differences between the two types of product are discussed. Keywords: Low carbon steel, hot rolling of strip steel, rolling mill log analyses, austenite grain size, grain size modelling.

Jan 1, 2004

By Claud Johnson, G. Roger Miller, Kristine M. Krajnak, Stacey Waugh, Oliver Wirth

Workers exposed to vibrating hand tools are at risk of developing symptoms such as cold-induced vasospasms, loss of tactile sensitivity, and loss of grip strength in the fingers and hands. These symptoms are known collectively as vibration white finger (VWF) or hand-arm vibration syndrome (HAVS). Symptoms of VWF or HAVS are in part due to repeated and prolonged peripheral vasoconstriction[1, 2]. The reduction in blood flow that occurs with vasoconstriction can result in oxygen deprivation (hypoxia) in soft tissues, such as nerves and muscle, and lead to functional and structural changes in these tissues. The present study examined muscle tissue to determine if vibration-induced changes in transcript levels and protein concentrations result in enhanced vasoconstriction and hypoxia. Manual dexterity was also assessed intermittently to determine if vibration-induced changes in cellular factors are accompanied by performance deficits. Methods An animal model was developed to study the biological and functional changes that occur in response to repeated segmental vibration exposures. In this model, the right paw of intact rats was exposed to a platform vibrated at a frequency 250 Hz and amplitude of 49 m/s2 to simulate the vibration characteristics of hand-held grinders. Three groups of 8 rats each were studied: a vibration-exposed group, an exposure-control group, and a cage-control group. Exposure sessions, with or without vibration, were conducted 4 hr/day, 5 days/week for 5 weeks. Manual dexterity was assessed intermittently during the 5-week exposure period with the Montoya stair-case test[3], which quantifies the rat’s ability to reach for, grasp, and retrieve small food pellets placed below the rat on different levels or steps. Following the 5-week exposure period, the flexor muscles of the right forelimb were collected for analysis of gene expression, protein concentrations, and immunohistochemistry. Results Vibration-exposure resulted in an approximate 2-fold increase in the expression of a2C and a1D receptor transcripts in flexor muscles (Figure 1). These receptors mediate norepinephrine-induced vasoconstriction in smaller arteries. Vibration-exposure also resulted in an approximate 2-fold increase in hypoxia-induced factor-1a (HIF-1a), a transcription factor that is expressed in response to tissue hypoxia. Western analyses demonstrated that restraint caused a decrease in a1-receptor protein concentrations in the flexor, but vibration-exposure prevented the restraint-induced reduction (Figure 2). Immunohistochemistry performed on flexor muscles (not shown) demonstrated that a1 receptors are primarily located in arteries; maintained levels of these receptors could contribute to prolonged vasoconstriction following repeated vibration exposure. The staircase test showed some performance improvement, or a training effect, in manual dexterity for the control groups but not the vibration-exposed group (Figure 3).

Jan 6, 2006

By J. Barrett

State-of-the-art wireless communication and location-tracking technologies will dramatically change the face of mine worker safety. The MineTracer System developed by a Liberty Lake Washington company is a broad capability wireless sensor network based on a new breed of technologies known as wireless mesh systems. In this paper, R&D Manager Jim Barrett summarizes the balance of engineering tradeoffs that result in a system that (1) performs well, (2) is survivable against many types of mine accidents, (3) operates for many hours post-accident on battery power, (4) meets stringent MSHA requirements for intrinsic safety, and (5) is economically affordable for the mines.

Jan 1, 2009

By C. Strachan

This paper presents an evaluation of tailings dam incidents from the 1994 USCOLD Tailings Dam Committee report. Comparisons are also made with water storage dam incidents from USCOLD reports and recent tailings dam incidents. The evaluation results show that tailings dam incidents are due to a number of factors including overtopping, static and seismic instability, seepage and internal erosion, and foundation conditions, and that no particular type of tailings dam or operational condition is more susceptible to incidents. In addition, the results confirm that tailings dams should be located, designed, operated, and reclaimed with a thorough knowledge of site conditions, mill operation, site monitoring, and tailings characteristics.

Jan 1, 1999

By F. J. Prokoski

The COALSTAR Project, which operated from November 1981 to December 1982, was a research and development project aimed at providing a reliable and inexpensive means of monitoring various waste site conditions via the GOES satellite system. The GOES system provides data transfer from unattended isolated sites where neither power nor telephone lines exist. The reliability and resolution of the data received while using the satellite link were excellent; however, the site instrumentation gave considerable trouble. The disastrous failure of a large coal waste embankment in 1972 led the Bureau of Mines to undertake a comprehensive program to reduce the likelihood of such an occurence again. Part of this program involved the installation of instruments to monitor the stability of a specially-selected embankment operated by Armco Incorporated near Montcoal, West Virginia. Initially, the instruments were monitored by normal telephone lines and used normal commercial power from the local utility. The project described here was initiated to replace this monitoring system with an unmanned, solar-powered data collection system which transmitted data via satellite to a central computer facility. The satellite data network is the National Earth Satellite Service of the National Oceanic and Atmospheric Administration.

Jan 1, 1984

By Manuel Rapiman, Ricardo Sepulveda

The feasibility study of Escondida Norte (ENorte), recommended a slope angle design for the Final Pit. But, according to the experience obtained with the slope adjacent to the West wall of ENorte, in which Compañia Minera Zaldívar (CMZ) gained in its phase 4, a slope of similar geotechnical characteristics will be exposed in the West Wall of Phase 1 (Premine) and of the Final Pit, with an interramp angle 53º and with very good stability results. In this regard, Minera Escondida Ltd. (MEL) performed a study of the slope angles for the phases mentioned and according to this delivered the results of this evaluation, the recommendations and/or the necessary conclusions in the design to ensure that the slopes are stable enough and may enable safe operational management of them.

Jan 1, 2006

By Michael Rieber

An analysis of coal slurry pipelines was presented in our May 1976 study, Route Specific Cost Comparisons: Unit Trains, Coal Slurry Pipelines and Extra High Voltage Transmission (4]. The present study extends that analysis. The earlier work included technical and economic cost descriptions of the black Mesa and ETSI pipelines as well as some hypothetical pipeline routes. Water problems, safety and environment, required resources, and labor impacts were discussed at some length. Additionally, pipeline impacts on competing railroads, slurry-rail comparisons, and cost escalation. were analyzed. The difference in pipeline profitability to an owner-operator versus a promoter-builder was suggested. These aspects are not redone in this study. Here, we present a synopsis of the previous results and a general statement of coal slurry pipelines. Extensions of the arguments are presented where they appear warranted. New material is developed in the area of pipeline branching and tapping. This would appear necessary if slurry pipelines are to function as more than private lines; if they are, for example, to be responsive to common carrier requirements.

Jan 1, 1977