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By Mark Kuchta

A new database application for long term production scheduling has been developed for LKAB's Kiruna mine. The scheduler uses a new block data structure whereby the monthly production data for three raw ore products are predetermined on a month-by-month basis for each production area that could be mined within the schedule time horizon. The production schedule is created by assigning the starting dates to the each production area subject to various mining operational constraints such that that the monthly deviations for the production targets are minimized. The system is well integrated into the mine's overall computerized mine planning system.

Jan 1, 2002

By J. Iannicelli

Kaolin, normally an inert filler when compounded with polymers, is converted into a strongly reinforcing pigment by prereaction with certain functional silanes. Modification of kaolin with amino and mercapto silanes allows it to form crosslinks and confers significant improvements in modulus, abrasion resistance, compression set and other physical properties of a broad range of polymers.

Jan 1, 1990

By M. D. Flavel

My paper relates to bond's third theory of comminution and suggests work be used as a basis for designing crushing and screening plants, this will give more accuracy than existing methods, As stated in the abstract, this paper is only a synopsis of my official paper, many of the questions that might arise in this brief address will be answered by referring to the detail i n the main paper $ Because of the limited time available and the fact that many people here do not need to study the aspects of crushing and screening in depth, i will highlight-those sections of the paper which show how major capital, operating and energy cost savings can be achieved in the process, I will develop the theme in the following manner, Firstly, pointing out, why a new approach is needed to the fundamentals of crushing and screening, Secondly, by setting forth some theory to describe what we are trying to accomplish, Thirdly, by looking at important factors which need to be observed in designing plants and applying machines to comply with this theory, Lastly, i will put forth some ideas on how we might develop this theory to make the industry more efficient, At the outset, i have to say my approach to this process is entirely new, for those used to applying machines and designing plants on existing criteria, they will find this theory easier

Jan 1, 1977

By W. C. Lacy

It is the responsibility of educators to look ahead and prepare young engineers and scientists to cope with industrial and social problems of the future. We are faced with a review of history as well as prophesy of the future. The mining industry exists in a "bubble" with little interaction or communication with the outside. This isolation must be broken down if the industry is to survive in the U.S. and Canada. The ability to communicate with the general public and public officials is essential. Many changes are occurring that will require readjustments in technology and staffing. Aging population will result in raising retirement and increasing available workforce. This may force shorter working weeks to supply additional jobs. Environmental concerns will likely direct more attention not only to these concerns during mining, but to planning for post-mining land usage. Retraining and up-dating educational programs are required to cope with these changes.

Jan 1, 1994

By Zhiyuan Shen, Dan Zhao

The abstract discusses the importance of reliable mine monitoring systems for preventing accidents. It focuses on diagnosing ventilation system failures caused by roadway faults that alter airflow resistance. The paper proposes using an improved Support Vector Machine (SVM) method to identify the fault location based on changes in air volume detected by wind speed sensors. The approach involves building a sensitivity 0-1 matrix and establishing a roadway fault scope library. The improved SVM method is tested on the Daming coal mine, demonstrating its effectiveness in diagnosing fault locations, reducing training time, and improving accuracy compared to traditional SVM.

Apr 5, 2022

By F. L. Jackson

The large scale transportation and storage of sulphur in the liquid state is a relatively new development, but is really only a logical extension of old mining and processing techniques, It is not known who the first person was to win a relatively pure sulphur from ore by melting, but this method was commercially used at least two hundred years ago in Sicily and is still in use today. The Frasch process of mining was invented over sixty years ago, and the development and improvement of-liquid sulphur pumping and handling techniques has paralleled the growth in the Frasch mining industry. During the last fifty years, improvements in the technology of using sulphur have included the premelting of sulphur prior to its being burned for acid production or conversion into CS2 and other compounds. Yet, until fairly recent times, sulphur produced as liquid has been solidified into large blocks at the producing point, broken down by blasting or with mechanical equipment, and shipped in bulk form as a solid.

Jan 1, 1962

By David S. Cahn

For many years the green and dry compressive strengths' of pellets have been, considered as possible criteria of pellet performance during induration. Although widely quoted throughout the industry, little attention has been given to standardizing the unfired pellet compressive strength test or to determining the characteristics of the test. The purpose-of this study was to compare the constant deformation rate test with that using a constant loading rate in addition, the dependence of these tests on such pellet properties as size, weight, and method of balling was to be investigated.

Jan 1, 1967

By E. Steel

The asbestifom habit is most commonly developed in certain amphiboles and chrysotile, but other minerals may also crystallize with this unususual habit, The habit may be characterized by 1) a fibril structure, single or twinned crystals of very small widths (generally less than 0.5 inn) which have gram with a common fiber axis direction but which are disoriented in the other crystallographic directions, 2) anomalous optical properties, primarily parallel extinction, 3) unusual tensile strength, 4) high aspect ratio, and 5) flexibility. In addition, there is evidence to indicate that some amphibole asbestos may have unusual surface properties.

Jan 1, 1979

By B. W. Cavender

The operating lifetime, or production rate, selected for a mining project is among the most important factors influencing the design and ultimate economic success of the project. An incorrectly-determined lifetime can lead to the erroneous rejection of projects as uneconomic as well as the suboptimal exploitation of producing properties. This paper examines the calculation of the optimal lifetime using both traditional discounted cash flow and recently-proposed option pricing techniques. Using each method, the production rate is determined as that rate at which the net present value of the project is maximized.

Jan 1, 1992

By H. L. Holden

The single line grinding circuit at Bond Gold's Colosseum mine consists of variable speed drive semi-autogenous (SAG) milling and secondary grinding with a fixed speed ball mill. There are several advantages and disadvantages of operating SAG mills with variable speed drives. Discussion in this paper will focus on the effects of variable speed SAG milling in relation to mill liner wear, grinding media consumption, and mill operating availability. Operating experiences, corresponding mill data, and pertinent design changes are also presented.

Jan 1, 1991

By F. Ikumapayi

Hydrogen peroxide production was measured during the grinding of a complex sulfide ore, and its oxidizing effect on solid surfaces was investigated using Fourier transform infrared spectroscopy (FTIR) with diffuse reflectance attachment measurement. In turn, an attempt was made to correlate the formation of hydrogen peroxide, surface oxidation and sphalerite flotation. Additionally, in order to predict and minimize detrimental production problems due to the recycling of process water in sulfide ore processing, the effects of major components of calcium and sulfate species present in recycled process water and the effect of temperature on sphalerite flotation were investigated through bench-scale flotation tests using complex sulfide ores. The significance of process water species in flotation was studied using tap water, process water and simulated water containing calcium and sulfate ions. Formation of hydrogen peroxide was revealed during the grinding of the complex sulfide ore, and its formation was counteracted by diethylenetriamine (DETA). The FTIR spectrum of the pulp solid fraction showed varying degrees of oxidized surface species, which are related to the concentration of H2O2 analyzed in pulp liquid. Bench-scale flotation using two different complex sulfide ores showed that sphalerite recovery is better in process water than in tap water. Flotation results also indicated a varied recovery of sphalerite at different temperatures in either tap water or process water.

By T. W. Beck, J. A. Organiscak

The U.S. National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) has recently studied several redirected scrubber discharge configurations in its full-scale continuous miner gallery for both dust and gas control when using an exhaust face ventilation system. Dust and gas measurements around the continuous mining machine in the laboratory showed that the conventional scrubber discharge directed outby the face with a 12.2-m (40-ft) exhaust curtain setback appeared to be one of the better configurations for controlling dust and gas. Redirecting all the air toward the face equally up both sides of the machine increased the dust and gas concentrations around the machine. When all of the air was redirected toward the face on the off-curtain side of the machine, gas accumulations tended to be reduced at the face, at the expense of increased dust levels in the return and on the curtain side of the mining machine. A 6.1-m (20-ft) exhaust curtain setback without the scrubber operating resulted in the lowest dust levels around the continuous mining machine, but this configuration resulted in some of the highest levels of dust in the return and gas on the off-curtain side of the mining face. Two field studies showed some similarities to the laboratory findings, with elevated dust levels at the rear corners of the continuous miner when all of the scrubber exhaust was redirected toward the face either up the off-tubing side or equally up both sides of the mining machine.

Jan 1, 2013

By R. L. Loofbourow

Most wet mines face unquantified water costs as well as the obvious wing costs. Both kinds of cost are multiplied by work at greater depth and by higher unit prices. This intensified challenge merits renewed or perhaps altogether new response. Any practicable way to reduce inflow tackles both obvious and unquantified costs. Ten groups of possible ways to do it are cited. Most have been demonstrated. Two are known from work other than mining. Surely new means can be found. Here are opportunities for operators of wet mines!

Jan 1, 1980

By Clarence O. Babcock

Model pillars of limestone, marble, sandstone, and granite, with length-to-diameter ratios of 3, 2, 1, 0.5, and 0.25 (0.286 for granite), were broken in axial compression to determine to what extent an increase in end constraint increased compressive strength. Radial end constraints of 13 to 23 percent of the average axial stress in the pillar, produced by solid steel rings bonded with epoxy to the ends of dogbone-shaped specimens, increased compressive strength somewhat above that of cylindrical pillars without ring constraint. However, when the results were compared with those obtained by other investigators for straight specimens of several rock types taken collectively, with L/D ratios greater than 0.5, the resulting strengths were not significantly different. Thus, the amount of end constraint produced by the solid steel rings was about the same as that produced by the friction from the steel end plates. In other tests a radial prestress of 3,000 psi or 5,000 psi was applied prior to axial loading by adjustable hardened steel rings to increase the constraint above that obtained for the solid rings. The average radial constraint stress, expressed as a percentage of the average axial pillar stress at failure for the 3,000 psi prestress, was 54.3 percent for limestone, 40.3 percent for marble, 44.7 percent for sandstone, and 23.4 percent for granite. The average radial constraint stress, expressed as a percentage of the average axial pillar stress at failure for the 5,000 psi prestress, was 74.2 percent for limestone, 51.2 percent for marble, 61.6 percent for sandstone, and 29.7 percent for granite. These constraints increased the compressive strength significantly above the strength of straight specimens and solid-ring constrained specimens. These results suggest that large horizontal stresses in orebodies mined by the room and pillar method should increase the strength of the pillars and allow an increase in ore recovery by a reduction of pillar size when major structural defects are absent.

Jan 1, 1969

By E. J. Rorem

Rockfall and unstable rock slopes can be con-trolled by using steel wire-rope net systems as barriers or as slope draping. The chief advantage of such systems over rigid type barriers is the flexibility of wire rope netting. This flexibility and strength permits kinetic energy dissipation with low maintenance requirements. Mining activities can produce temporary or long-term unnatural slopes and unstable rock faces that may produce rockfall hazards. Such conditions can necessitate efforts to minimize the hazard to workers, structures and equipment.

Jan 1, 1996

By J. T. YIi-Penttiia

Dust formation and reaction mechanisms of copper matte particles were investigated in simulated flash oxidation conditions. The granulated and ground matte consisted of 72 wt% Cu, 4 wt% Fe and 21 wt% S. Experiments were conducted by using a laminar-flow furnace with a reaction gas composition ranging from 20 vol% to 75 vol% O2 in nitrogen. The particle feeding was carried out by the single-particle method and samples were quenched after a specified reaction time (approximately 0.05-004 s) in a cold water film. Experimental temperatures were between 800 and 1300°C. Chemical analysis was used to determine oxidation degree, and an optical and scanning electron microscope combined with energy dispersive analysis was used for characterization of the reacted particles.

Jan 1, 1998

By Carl E. Williams

During the past two years a computer program called "COPOR," Computerized Open Pit Optimization Routine, has been developed and used for mine planning of several base metal deposits. This routine utilizes a three dimensional computerized block model of an orebody, some economic parameters and operating constraints to locate the mineable or economic limits of the deposit schedule the yearly production from the mine and produce bench by bench ore reserve summaries and maps of the yearly and ultimate pit configurations. The moving cone method is used to perform these functions with a conventional block model. This model is conventional in the sense that each block is assumed to be homogenous; i.e., either ore or waste but not a mixture of the two. Due to the nature of a seam type deposit this approach is not realistic; therefore, revisions have been made to form a new version of the COPOR program. This version has been named "COALOR," Coal Optimization Routine. COALOR contains all of the power of the COPOR program but is equipped to handle the intricacies of coal seam type deposits. The deposit can be composed of a single seam or multiple seams which are horizontal or dipping at any angle. The numerous coal quality values can be incorporated to aid the optimization of the economic pit limits and yearly scheduling.

Jan 1, 1978

By Keith G. Wallace

The effect of face resistance on ventilation air leakage through stoppings was measured in a twin development heading. Face resistance was varied by alternately tightening or loosening the face line brattice to change the line brattice leakage. Results indicated that tight brattice lines are necessary to maintain acceptable airflow at the face but result in higher leakage throughout the entire system, reduced overall ventilation efficiency, and higher operating costs. Conversely, a low face resistance which simulated an auxiliary fan/duct system gave reduced stopping leakage losses, higher quantities of air at the last open cross-cut and greater entire system efficiencies

Jan 1, 1984

By R. H. Ring

The Automatic Extraction System (AES) was designed and built under a U.S. Department of Energy Contract by the National Mine Service Company in cooperation with the Lee Engineering Division of Consolidation Coal Company. The Pennsylvania State University, Mining Engineering Section, was contracted as an independent auditor of the AES performance. The AES had a rotating cutter drum like a continuous mining machine; but two hydraulically powered roof supports, four roof-bolting drills, a dust scrubber, a ventilation fan and ducting in the roof supports, semi-automatic control, an extensible chain conveyor, and other innovations led to the distinction "extraction system" as opposed to "miner-bolter" or "continuous mining" machine. After design and assembly, the AES was field tested experimentally in an underground coal mine. The in-mine performance audit was preceded by a computer simulation of the potential production for a later comparison with the actual tonnage mined by the AES. This paper describes the results of an in-mine trial and assesses the production potential of the AES.

Jan 1, 1980

By J. C. Draper

This subject was introduced last April in a paper presented in Birmingham, Alabama, by James E. Elkin, General Superintendent of Duquesne's Coal Department. This paper will cover some of the same data and in addition it will update and further describe our experience. Our Portal No. 3 was started in June 1965 with battery tractor-trailer face haulage. This mine is operating in the Sewickley seam in Dunkard Township, Greene County, in Southwestern Pennsylvania as shown on Fig. 1. The Warwick group of mines fronts on the Monongahela River and extends westward for some ten miles as shown on Fig. 2.

Jan 1, 1968