Search Documents

By I. Demers, A. Blier, M. Mbonimpa, M. Benzaazoua, B. Bussière

The Doyon Mine in Quebec, Canada, evaluates the possibility of desulfurizing its tailings to produce material to be used as cover for the acid-generating tailings disposal site. Laboratory tests showed that a single-layer cover made of desulfurized tailings placed over reactive tailings can prevent the generation of acid mine drainage. Modeling with the software Vadose/W was used to optimize the design parameters, namely, cover thickness, water table position and residual sulfide content of desulfurized tailings following laboratory work. It was found that the optimal configuration includes a 1-m (3.3-ft) desulfurized tailings cover containing 0.8% S, with the water table kept at the interface between the reactive tailings and the cover. To maintain the cover performance to reduce oxygen flux toward acid-generating tailings even in the event of a long dry period, a sand layer is suggested to protect the cover from excessive evaporation. It is possible to reach the environmental objective for oxygen flux chosen for the Doyon Mine (10 mol/ m2/year) with the protective sand layer, even in extremely dry conditions.

Jan 1, 2009

By R. Adsero

The volume of data produced by operating mines has increased substantially over the last 10 years. However, the volume of data and analytical capability has been negatively correlated to equipment productivity for at least the last seven years. In simple terms, as the volume of data has increased equipment performance has declined. Table (2010) tells us that ?The calamity of the information age is that the toxicity of data increases much faster than its benefits?. More data does not guarantee improving productivity; but more data is also not the cause of declining productivity. Similarly, when equipment performance does start to improve, (it must ? there really is no option if mines want to remain competitive), it will not be the data nor analytics which causes it; it will be the people using the resources at their disposal; including the data. Data and analytics can help if the toxicity of the data can be managed. The simplest form of business improvement using data is benchmarking. The objective of benchmarking is to understand and evaluate the current position of a process in relation to ?best practice? and to identify areas and means of performance improvement. The application of benchmarking involves four key steps: (1) Analyze and understand in detail existing processes; (2) Analyze and understand the processes of others; (3) Compare your own performance with that of the others analyzed; and (4) Design and implement the changes necessary to close the performance gap(s). There are however, many in the mining industries who have shunned equipment benchmarking because they believe that, ?every mine is a pilot?. In other words, the differences between mine operations make comparisons between them of little value. This paper will present a valid approach to benchmarking equipment performance and reliability, accounting for the differences and similarities between operations, producing a result which can be used to add value to mines around the world.

Feb 23, 2014

By C. R. McClung

"Molybdenum, in the form of molybdenite, is a common byproduct of many copper mining and concentrating operations. Contrary to most copper sulfide minerals where recovery is principally liberation controlled, the recovery of molybdenite is much more complex with fully liberated particles commonly lost to tailings. It is this complexity that facilitated the necessity for a geometallurgical investigation of molybdenite from the Bingham Canyon deposit. The aim of this investigation was to determine the effect mineralogy and/or mineralogical attributes (i.e. morphology, angularity, liberation, size) have on the recovery of molybdenite in the processing circuit. A set of samples was collected from the ores and products produced by Rio Tinto Kennecott’s Copperton Concentrator. All samples were analyzed using normal polarized reflective light, Mineral Liberation Analyzer (MLA) and X-ray diffractometery (XRD) techniques. The results of this investigation revealed the presence of two distinctly different types of molybdenite, which have been identified as the two polytypes of molybdenite, i.e. hexagonal (2H) and rhombohedral (3R). The 2H polytype occurs as textbook-shaped particles in quartz-molybdenite veins that are located in the core of the Bingham Canyon deposit. The 3R polytype occurs as disseminated, “ball”-shaped particles with a dull or frosted appearance along the margins of the mineralized intrusive body or central core. Concerning their metallurgical behavior each type exhibits unique metallurgical properties that are consistent with those reported in the published literature. For instance, the 2H polytype is easily ground and kinetically “faster” floating with surface attributes that are amenable to higher rates of recovery. This commonly results in the production of a high quality molybdenum concentrate under normal operating conditions common to most copper concentration operations. In contrast, the 3R polytype is difficult to grind and kinetically “slower” floating with surface attributes that less amenable to recovery under normal operating conditions. Therefore, in deposits with higher concentrations of the 3R polytype, modifications to the normal operating parameters may be necessary to improve the recovery of molybdenum. Finally, a preliminary investigation into the metal budget of porphyry Cu and Mo deposits indicates that a positive correlation may exist between the total economic metal budget and the polytype content. For example, higher concentrations of the 3R polytype appear to be more prevalent in Au-enriched porphyries versus Mo-enriched porphyries. This observation may also serve to help explain why it is easier to obtain high rates of recovery in Mo ± W-rich deposits, which contain little to none of the 3R-polytype. Consequently, the potential for the metal budget of a porphyry deposit to be used as an indication of the molybdenite polytype present, as well as its impact on the economics (exploration) and/or on the processing circuit (plant design) could exist. In conclusion, this investigation highlights the necessity of understanding the mineralogical properties or characteristics of molybdenite and/or other economic mineral(s), as these can and will have a direct impact upon the performance and plant optimization."

Jan 1, 2016

By Brian Zelenko, William H. Hansmire

"By the time the latest expansion of the Washington Metropolitan Area Transit Authority (WMATA) system, known locally as Metro and which opened in 1976, is completed in 2020, the system will serve 97 stations and operate on 188 km (117 miles) of track on six interconnecting lines. Metro provides a critical transportation link to a population of approximately six million people within a 3,900-km2 (1,500-sq-mile) Washington Metropolitan area and has allowed job growth to expand to all corners of the region. In the 1950s and 1960s, when the system was first conceived and construction began, most jobs were centered in downtown Washington, and most of the workforce commuted by bus or car. Today, transit-oriented development has increased residential, commercial and government facilities near most of the existing 91 stations increasing the importance of the Metro system as a critical transportation link for the region. According to recent American Public Transportation Association (APTA) data, Metro is the second busiest transit system in the United States (after New York City’s transit system).During the nearly 50 years of construction on the Washington Metro system, technology improvements and lessons learned from the global tunneling industry were implemented. Portions of this background and history have been adapted from other work by the authors Roach et al. (2017) and expanded for use herein. For soil tunnels, these improvements included the change from a “two-pass” tunnel lining with a typical initial lining of steel ribs with wood lagging or segmental precast lining erected within the tunnel shield followed by a final lining of cast-in-place concrete to a one-pass lining system of pre-cast concrete gasketed segmental lining. Soil tunnels were originally excavated using open-face tunnel shields, but changed over time. By the late 1980s, tunneling using closed, pressurizedface tunnel boring machines (TBMs) using a one-pass tunnel lining consisting of segmental precast concrete permitted tunneling in a wider range of soil conditions with much less risk of damaging overlying utilities or structures, greater safety for tunnel construction personnel and without the need to dewater the soils. However, due to concerns about conditioning clays with earth pressure balance (EPB) TBMs, open face machines were still favored by contractors for their better advance rates, lower cost and ability to deal with boulders that were occasionally encountered in the Coastal Plain Terrace Deposits."

Jan 6, 2018

By Cal D. Iles

Decreasing ore grades and increasing labor and material costs have seriously eroded the economic vitality of many mining operations. Coupled with global economic stagnation and recession in the early 1980's, these conditions have forced reevaluation of operating strategies and methodologies with the objective of remaining competitive in a world marketplace. A concept offering large potential benefits is hardrock portable crushing and conveying. Implementation of this system at Duval Corporation's Sierrita open pit copper-molybdenum mine (Figure 1) has significantly reduced mining costs, becoming a major part of Sierrita's cost reduction strategy. Located 48 km south of Tucson, Arizona, the 209 000 t/d property has one portable 60x89 gyratory ore-crusher in operation with tentative plans for two additional units.

Jan 1, 1985

By L. S. Gertsch, M. Z. Abu Bakar

Linear cutting tests of a porous sandstone with a radial drag pick show that saturation of rock with water can increase the specific energy of fragmentation. This appears to be due, in this case, to a saturation-induced increase in the forces acting on the cutting tool without a concomitant increase of the fragmented volume. The mechanisms of this reaction are explored by examining various responses of the parameters controlled and induced during the linear cutting tests, such as cut spacing, cutter penetration, three-dimensional forces and muck production. A program of load-indentation testing is underway to evaluate the permeability threshold of this behavior. These findings are opposite from those made when the same rock is cut with a constant cross-section disc cutter reported elsewhere (Abu Bakar and Gertsch, 2011). Such results highlight the effects of different cutting tool designs, and indicate the need for a well-coordinated program of research to support effective excavator design and selection.

Jan 1, 2012

By Russell L. Wood

The title of this session seems to have been picked especially for this paper. It is 1984, it is the morning after, and there is one monumental hangover among many if not most of the oil companies that have invested in mining in the past decade or so. How an oil company looks at mining depends on what time period you are talking about. A few years back around the time of investment this is what they were probably looking at: 1. A balance sheet of their own that was beginning to go wild, with many of their commodity prices having already seen increases of two, three, or four fold, and with no end in sight. 2. A need to invest their earnings someplace fast before the stockholders or the government got too interested. And that someplace should be in an industry where their own management skills could be applied. (Only a true cynic would suggest that this is a form of job security) 3. In mining there was an industry amazingly similiar to their own, one working with non-renewable natural resources, dealing with the same types of government agencies, and having the same type of critics and pressures from the general population. 4. An industry that was somewhat backward as compared with their own, and one where a generous ration of the capital and management skills so handsomely bestowed upon the oil industry could be used to great advantage.

Jan 1, 1984

By Bo R. Arvidson

The strongest magnetic roll separator available on the market enhances certain industrial minerals purity to levels not reached previously. Exceptionally strong forces can also be utilized for processing relatively fine particles at feed rates several times greater than for prior art electromagnetic induced roll separators. Since the unique machine does not work with an air-gap, coarser particles than what has been considered practical can be separated at rates up to 20 tph per single machine unit and 40 tph for a double machine unit. Examples for all these three application areas will be given. While the roll separator can be used only for dry processing presently, the other new separator can be used for both wet and dry applications. It is a medium-intensity, high- gradient magnetic separator employing a filamentary matrix. It was primarily developed for recovery of weakly magnetic iron ore fines, but it is finding applications for cleaning of industrial minerals such as wollastonite, calcite, clay and talc. Its main advantage is a simple design resulting in a very lm cost machine both with regards to total capital investment and operation. A significant technical advantage exists also. The metallurgical performance is similar to conventional electromagnetic separators, while the cost per ton is about half of such separators.

Jan 1, 1985

By John J. Dran

In recent years, market rates of interest have risen well above their historical long-term average. Also during this period, the short-term variability of interest rates has been greater than in prior years. Interest rates have a significant effect on the operation of our economy. They influence the extractive industries in a number of ways. Their major long- range impact is on investment decisions - specifically the valuation of mineral deposits. An understanding of the factors that influence interest rates is important to the engineer or businessman who makes the investment decisions for the mining company. The effect of changes in the market rate of interest on the value of mineral reserves is critical to the future financial success of the mining enterprise. The most common simplification of the factors determining the level of interest rates is that they are a function of the demand for and the supply of money. While this is an oversimplification, most businessmen would be hard- pressed to provide a better explanation. The purpose of this paper is to explore certain fundamental economic aspects of interest rates and to examine their effect on the analysis of investment in mineral deposits.

Jan 1, 1975

By C. H. Stephenson, Z. White

This paper presents the design approach case study for incorporating a Technogrid® conveyance End-of-wind arresting system within the new South32 Hermosa headframe. Focus is placed on energy absorption requirements, structural integration, and mounting details tailored to the geometry and operational constraints of the headframe. Key considerations include arresting forces, load path continuity, and connection design to ensure reliability and maintainability. The paper also discusses coordination with other headframe systems and the iterative design process used to meet safety standards and client objectives.

Feb 22, 2026

By Joseph O. Cook

I know this is, at best, a frustrating period for the coal mining industry. About 20,000 miners have been laid off, mostly in the Appalachian and mid-western areas, and several mines are working less than 5 days a week; however, the industry is experiencing modern growth and, at least, there is the potential for future growth. The coal industry is probably only operating at about 80 percent of its present capacity, and it is certainly capable of helping this country solve its energy problems. Growth, as a rule, does not come easy, and growth in the coal industry is no exception to this rule. Many formidable challenges have to be overcome. As we all know, mining relies very heavily on the earth sciences, which have advanced significantly in the past few years, but we are always working in a changing environment which in most cases is a hostile environment. Large quantities of material are quickly extracted and rapidly moved in, generally speaking, a very confined area. The very nature of the mining business directly and constantly impacts our environment during this period in which the Nation and the world has become increasingly smaller and more concerned about protecting our environment. In addition, growth brings about an expanding work force which is increasingly younger and less experienced.

Jan 1, 1980

By G. Robert Guillet

Nepheline syenite is a light-colored feldspathic rock that is used primarily as an addition to the glass batch. It is also used in ceramics and as an industrial filler. Composed essentially of the soda and potash feldspars and nepheline, nepheline syenite contributes needed alkalis and alumina to the glass composition. And because it contains a higher proportion of these oxides per unit weight, it is a formidable competitor for feldspar in northeastern North America and parts of western Europe. Nepheline-bearing rocks are not uncommon on a world scale, but few are able to be beneficiated to a composition sufficiently low in iron to be used in the making of glass. Nepheline can only form in an environment deficient in silica. Hence free silica, as quartz, is always absent in the primary mineral assemblage. Biotite, hornblende and magnetite are usually present as minor accessory minerals, and zircon, garnet, muscovite, and apatite may be present as trace minerals. Nepheline syenite is produced for glass, ceramics, and filler markets by Unimin Canada Limited at Blue Mountain, in south- eastern Ontario. Unimin acquired the former Indusmin and IMC properties from Falconbridge Ltd. in 1990. Elkem Nefelin AIS commenced production of similar products from Stjernoy Island in northern Norway in 1961. Unimin acquired this company in 1992. Nepheline has also been a byproduct of apatite mining on the Kola Peninsula for many years, and in 1951 the production of alumina from nepheline was commenced in a plant near St. Petersburg (Leningrad). There are now four plants in the Russian Republic, two smaller ones based on nepheline tailings from apatite mining and two larger and more recent plants in central Siberia using other nepheline resources. All four of these plants are integrated complexes that produce alumina for the subsequent production of aluminum metal, sodium and potassium carbonates, and portland cement. Roofing granules are produced by the 3M Company from a nepheline rock in Arkansas. In 1980 and 1989, trial shipments of nepheline syenite were recorded from new sources in Brazil and western Turkey respectively. Recent interest is also recorded for deposits in China, Saudi Arabia, and British Columbia.

Jan 1, 1994

By Bryson D. Trexler

Man's activity in developing, operating, and abandoning a mine often affects the quality of the ground water and surface water. Acid water drainage from mines is an example of an impact from mining that results in degradation of ground and surface water. New flow systems are created by the mining activity. The mining made possible complex chemical reactions that, with water movement, create a discharge of low pH, poor quality water. Remedies for these problems fall into two general solutions: 1) treatment of the end product and 2) reversal of some aspect of man's disturbance of the natural system. The relative reversibility of various aspects of man's impact from mining activities ranges from relatively easy to very difficult, from economically feasible to economically infeasible, and from technically possible to essentially impossible with present knowledge. The relative reversibility of a mine-related problem cannot be assessed without first understanding the detailed physical interactions that combine to form the problem. Acid water drainage is a combination of the availability of several chemical factors with the availability of water for a transport mechanism.

Jan 1, 1982

By Robert L. Grayson

An application of goal programming (GP) in evaluation of proposed purchases of major mining machinery is presented. It incorporates historical operating data compiled on mechanical delays to production time. The goal programming technique, which is an extension of integer programming, is used to maximize an objective function. The objective function combines the capital budgeting evaluation methods of net present value, payback period, profitability index, and total net earnings as goals weighted according to a management preference. The GP method gives an optimal solution to a multiple-goal problem. A sensitivity analysis is performed to determine the effect of an increased production forecast or a tightened budget on proposal selection.

Jan 1, 1982

By Allan R. Ide

It is a great pleasure for me to speak-before such a prestigious group as the American Institute of Mining, Metallurgical and Petroleum Engineers. The substance of my talk today is the handling of coal and petroleum coke: their characteristics and environmental problems, and how we were able to correct the problems, prescribe the cure and enjoy the benefits. When coke first became a by-product derived from the oil refineries everyone would have been very happy if someone had offered to take this pro- duct off their hands. Unfortunately, there was no market at that time, and no one seemed interested. Soon thereafter, it became a sellable product and began to be shipped to many countries in the world. This was when all of the pollution problems began. I will be talking briefly about some of these problems and showing a short film on this subject afterwards.

Jan 1, 1984

By Yi Luo, Jianwei Cheng, Mingming Li, Lei Xiao

Concealed thermal events in longwall gobs present safety hazards for underground coal miners and can significantly interrupt mining production. The probable causes for such thermal events range from coal oxidation at slightly above ambient temperature to smoldering fires due to spontaneous combustion of the broken coal left in the gobs. Locating such “hot spots” is the key step for planning and implementing mitigation measures to bring such thermal events under control. If a mine section, or even an entire mine, has to be sealed, understanding the status of the sealed mine atmosphere is important for the decisions guiding subsequent actions. The gas composition data obtained through the tube bundle mine atmospheric monitoring system is firsthand information of great value. Fire ratios proposed by various researchers and derived from gas composition data are useful in determining the fire status and even approximating the source locations (Timko and Derick, 2006). However, the applicability of each of these ratios under particular conditions should be carefully evaluated. The use of properly combined fire ratios can enhance the certainty of analysis. The explosibility of a sealed mine atmosphere deserves primary concern for safety reasons during seal construction, idle time and reopening of the sealed area.Mine atmospheric monitoring data from a longwall mine with flame fire have been analyzed. Efforts have been made to identify the possible causes, locations and statuses of these events using the obtained gas data, as well as other ventilation, geological and mining parameters. The effect of injected inert gas to control the events has also been quantified. The explosibility of the sealed atmosphere has been determined using two methods.

Jan 1, 2012

By M. E. Ryan, C. L. Hoebbel, E. J. Haas

DISCLAIMER The findings and conclusions in this paper are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of any company or product does not imply endorsement does not constitute endorsement by NIOSH. ABSTRACT It has been suggested that effective disaster prevention and response in mining requires that elements of emergency management be incorporated into everyday operations, planning, and decision-making, much in the same way that the industry approaches routine risk management. Since Congress passed the MINER Act in 2006, the newly mandated structural and technological advancements in mine emergency response preparation have been made and are apparent, but measureable improvement in mineworker emergency preparedness is difficult to ascertain. To begin exploring whether measurable indicators of mine workforce preparedness can or should be addressed within a risk management framework, NIOSH researchers examined the datasets from two separate research efforts—one which measured the organizational safety climate and self-reported safety performance, and the other which measured individuals’ perceptions of their own self-escape competency. INTRODUCTION In response to the mine disasters in 2006, the United States Congress passed the Mine Improvement and New Emergency Response Act (MINER Act), which strengthened existing regulations [30 CFR, Part 48] and introduced new provisions to improve mine emergency response. Since that time, new technological and structural features, such as mandated redundant communication systems, personnel tracking systems, and lifelines in primary and secondary escapeways, have been installed in underground coal mines across the country. Additionally, mine operators are required to develop emergency response plans, provide adequate supplies of breathable air throughout the mine, provide more frequent and realistic expectations training, and are required to immediately notify the Mine Safety and Health Administration (MSHA) in the event of an accident. While the structural and technological advancements in emergency preparedness are readily observable and easily measured, levels of individual mineworker preparedness remain difficult to assess. There is a general consensus that deficiencies in competence in the non-routine tasks required for individual miners to effectively respond to a mine emergency likely remain (e.g., National Research Council [NRC], 2013), and NIOSH research continues address this concern (Haas, et al., 2015; Hoebbel et al., 2018). To maximize an operation’s capacity to effectively prevent disasters and/or respond to emergency events, it has been suggested that individual and emergency management efforts be incorporated into everyday operations, planning, and decision-making in much the same way organizations manage routine risks to health and safety (Haddow et al., 2017). To the authors’ knowledge, the mindful intersection of routine risk management policies and practices and emergency prevention and response readiness have yet to be empirically studied within the mining industry.

Jan 1, 2019

By Robert Moore Lewis

Extensive exploration is being undertaken throughout the world in search for heavy minerals, particularly rutile and other titanium minerals. The federal government is sponsoring research involving rutile ores and recovery of stockpile-grade concentrates from domestic sources. Producers are being forced to turn to deposits with a heavy mineral content as low as 0.50% (essentially rutile and zircon). The North Carolina State University Minerals Research Laboratory investigated the possibilities of recovering heavy minerals from the amine tailings of the Texasgulf Inc.'s phosphate plant at Aurora, North Carolina. One laboratory beneficiation procedure using gravity, electrostatic and magnetic processes, resulted in the recovery of 78.7% of the heavy minerals in the amine tailings. Based on this percentage recovery and the present rate of phosphate mining, approximately 13,000 tons per year of heavy minerals (principally ilmenite and zircon) with a potential value of approximately $1,045,000 (1977) could be recovered. The economic potential for recovery of these heavy minerals appears to be favorable. A flotation procedure for up-grading the heavy minerals content in the amine tailings has been developed at the Laboratory, which could allow for concentration of heavy minerals and storing them in tailings area other than main tailings for future processing.

Jan 1, 1978

By Efstratios Karampinos, John Hadjigeorgiou, Philippe Morissette

"Ground support is a critical element in maintaining the stability of mining drives in deep and high stress mines. In challenging ground conditions, it is necessary to continuously explore ground support strategies that can control the resulting large deformations. It is an objective of mining operations to optimize the ground support by selecting appropriate systems at the time of installation of each reinforcement element. A successful ground support strategy will result in the use of a system that ensures both the structural and operational integrity of the excavations and mitigates the need for rehabilitation.Preliminary ground support design is often based on empirical observations and methods. Once a design is implemented, field trials, observations and in situ pull tests are used to fine tune or improve the design. Although not often employed during this process, numerical modelling can provide helpful insights into the impact of different ground support strategies. In this respect, it is possible to explore the use of multiple options before selecting the most promising ground support system for implementation in field trials. The challenges associated with the numerical modelling of rock support for mines have been described by Lorig and Varona (2013) and Potvin (2017). The employed numerical models should capture all potential failure modes of reinforcement throughout the mining sequence of the excavation. In particular, it is important to emulate the observed in situ ground support performance, as well as the influence of the installation sequence of the support. However, the time and expertise required for this type of modelling of ground support is often not available at mine sites. Even when the expertise is available, it requires a major time commitment and commitment of resources to set up, run and calibrate the sophisticated models capable of explicitly capturing the behavior of ground support.Rock reinforcement is an integral part of all ground support systems used in underground mines. Long, flexible tendons can reinforce the rock mass deeper into the walls and create a thicker reinforced shell around the underground excavation. This article focuses on the optimization of the cable-bolting strategy in squeezing conditions at the LaRonde Mine in Quebec, Canada by integrating the 3D distinct element method (DEM) in the design process. A calibrated numerical model is used to investigate a series of cable bolt configurations and provide recommendations for the ground support design."

Jan 4, 2018

By Calvin L. Stevenson

The probability of a particle passing through a maze is predictable and consistent. This principle may be utilized to effect a particle size separation of materials by presenting a physical maze to a stream of material that will allow the fine particles to pass, while deflecting the coarse particles. A maze is effective even though all apertures encountered are many times larger than the particles being separated. By designing a machine that allows the probability parameters to be controlled and varied without changing physical dimensions, probability sizing becomes a useful tool for the separation of granular materials.

Jan 1, 1967