Search Documents

By Otis M. Clarke

The 34th Forum on the Geology of Industrial Minerals gave members a chance to see the geology of various stone and ore deposits displayed graphically in quarry walls and also provided an opportunity to hear and see first-rate papers and posters on the geology of industrial minerals. Also, some field trips passed through areas of spectacular scenery. As a bonus, participants saw scenic mines, some of which are "pretty as a picture." Watercolor paintings prove it. At the Oklahoma Forum, the writer displayed a number of paintings of mines and other landscapes seen during previous Forum trips. These paintings and this brief article are part of a crusade to prove that some mines and geologic vistas are scenic wonders and belong in our visual heritage. It is a plea to save some of our best geologic exposures for future geologists, tourists, and artists.

Jan 1, 1999

By Norman Miskelly

Substantial progress has been made over the last ten years in the development of uniform national and international standards covering the definition, estimation and public reporting of mineral resources and mineral reserves. Agreement between the major participating countries has been reached, which include the requirement that a Competent Person prepares and approves publication of mineral resources and reserves. Most national regulatory organizations have accepted the new standards and have included them in the rules that must be followed by mining companies operating under their jurisdiction. These developments are the result of a concerted effort on the part of professional societies, national regulatory agencies, international organizations, and many dedicated individuals. The historical development of these standards is summarized in this paper. Accepted definitions of mineral resources and mineral reserves are discussed, as well as the definition and role of the Competent Person. Additional effort is needed before the international standards are fully understood, accepted and followed by mining companies, regulatory agencies, the investment community and the general public. Steps being taken toward development of a Mineral Reserves International Reporting Code Template (International Template) that will be available for all countries to use in deriving their specific country reporting codes, are outlined

Jan 1, 2003

By W. M. Hart

Business Process Improvement (“BPI”) Change to Survive “It is not the strongest of species that survive, nor the most intelligent, but the one most responsive to change.” [Charles Darwin] “If you want to understand something, try to change it.” [Kurt Lewin, social scientist] Many companies have tried one or more process management initiatives. Each effort may help develop a culture that is more receptive to change. Executive Management needs to be unwavering in support of change with systems and structures, staffing, development of people, measures, with incentives and rewards. General Electric developed principles for quality change management that are necessary for effective, continuing Business Process Improvement (BPI). Change Acceleration Process (“CAP”) One of the tools General Electric developed has been used successfully by companies around the world in a wide variety of industries. This tool, named Change Acceleration Process (“CAP”), is designed to improve acceptance of change. Acceptance is the method by which the creative energies of the workforce can be fully tapped. Over time, every employee receives CAP training at least once, and in many instances three (3) or four (4) times, and will work on one or more High Performance Teams. Thus, BPI can achieve and maintain its goals. The CAP tool focuses on: • Leading Change • Creating a Shared Need • Shaping a Vision • Mobilizing Communication • Making Change Last • Monitoring Progress • Changing Systems and Structures

Jan 1, 2006

By Scott G. Britton

Until now, only the range of typical construction projects which are repeated over and over during the life of a coal mine have been discussed. This chapter looks at underground construction projects which occur only once or twice during the life of any given mine and are major construction projects in both time and cost. These projects usually require the services of an outside engineering and construction firm with hands- on experience in design installation. Because of this involvement with engineering and construction firms (EIC), the role of the construction engineer will change from one of actively de- signing and directing tasks to one of planning, inspection, and quality control. To reflect this role change in the discussions, the focus of this chapter will be changed to a broad overview of project participation. Of course, the projects under consideration in this chapter could easily fill more than one book on their design and installation. In addition, major construction projects are extremely site specific, requiring months of data collection about site geology, physical conditions, and potential excavation and construction requirements. Therefore, no attempt shall be made to discuss any detailed construction aspects as was done in earlier chapters. The purpose of this chapter is to present the fundamental concerns of a staff engineer or supervisor. This engineer does not make the decisions on choosing the EIC firm, but assists and interacts with their project team to accomplish the goals set forth by higher management. The construction topics to be reviewed fall into three main categories. The first category is highlighted by the installation of a main surge bin; the second is typified by the construction of an underground shop; and the third category encompasses special projects such as rotary dumps, crusher stations, and foremen's offices. These categories highlight the differences between degrees of mine responsibilities for project completion. The first topic is usually a turnkey project by an E/C firm for a given mine. The second topic represents the leading role of the mine in the project with a contractor as a support service or equipment supplier only. The third topic, special projects, is an example of a joint venture-between a contractor (leading partner) and mine management. These roles can change with any given project, but the changes in management responsibilities for the construction engineer can be nicely illustrated for the purposes of this text. The first step toward constructing major mine projects is to analyze the mine which influence their design. From the mine management standpoint, these parameters should reflect the role the mine will play in the project construction. In other words, what is the nature of the proposed mine environment and what are the material, labor, and time requirements needed to assist or direct the chosen engineering and construction firm? Answering these questions requires some basic project planning and cost estimation work. Here, only a general treatment is necessary, since detailed discussions of these topics will follow in Chapters 8 and 10. For those persons interested in the role of the EIC contractor, I suggest beginning by reviewing the article by Beall, "The Role of an Engineering and Construction Contractor," presented in the October 1980 issue of Mining Engineering magazine.

Jan 1, 1983

By J. E. Gebhardt, J. A. Herbst, K. Y. Lee

Benefits of proper control of reagent usage in flotation circuits are typically improved metallurgy and savings in reagent costs. Improved metallurgy can mean more consistent product quality, i.e., final concentrate grade, better recovery of product values from the feed, or higher plant throughput at existing target recovery, and grade values. Flotation performance is sensitive to a variety of process disturbances which occur in operating plants, such as changes in flow rate, percent solids, size distribution. flotability of mineral species, etc. A way to handle these variations is to fully understand the dynamic flotation responses to disturbances and to implement a suitable control strategy to compensate for these disturbances. Depending on the objectives of the control system, various types of control strategies are available which employ different levels of refinement to achieve the desired performance. Typically, variables such as collector and frother dosages and reagent addition points can be manipulated to affect the performance of the circuit. In the case of sulflde mineral flotation, manipulation of the process electrochemical potential, in flotation and in grinding, offers another degree of process control. Because of the complex and interactive nature of flotation process variables, optimized reagent control requires consideration of all, or at least the most important, interactive variables of the flotation circuit. Model- based optimizing control provides a framework to handle the complex and dynamic nature of flotation reagent process control.

Jan 1, 1994

By R. G. Darmody

Chemical problems associated with surface mining, such as acid generating materials, are important and well documented. However, reclamation research has shown that poor soil physical condition is the most limiting factor to successful row crop production on reclaimed mined land. Critical to success are selection of the best available soil materials used in soil construction and a material handling method that minimizes soil compaction. Excellent corn and soybean yields have been achieved on low strength soils both in high weather stress years as well as low stress years. Total crop failures have occurred on high strength soils in years of weather stress. Some deep tillage practices have been successful in improving compacted soils, but it is preferable to avoid compaction when the soil materials are handled. Soil strength measurements with a cone penetrometer have proven to be a useful tool in evaluating rooting media and reclamation practices. Research has shown that surface mining can be a short term land use that may be followed by productive farmland, if reclamation is done correctly.

Jan 1, 2002

By Gary B. Glass

Seventeen percent of US coal production now comes from the 19 surface coal mines in the Powder River Basin of northeastern Wyoming. The Powder River Coalfield, which coincides with this topographic and structural basin, is unique to the conterminous US, in that it contains an estimated 934.4 Gt (1.03 trillion st) of in-place coal resources. At least 13.2 Gt (14.6 billion st) is a compliant, strippable reserve base. In 1993, an estimated 162 Mt (179 million st), or 98% of the coal mined in this Wyoming coalfield, came from the thick - average 30.5 m (100 ft) - subbituminous, Wyodak coalbed, or from the Anderson and Canyon coals in the one mine where the Wyodak is split into two separate coalbeds. The other 2.7 Mt (3 million st) of coal mined in the Powder River Basin in 1993 came from the School, Badger, Monarch and Deitz No. 3 coalbeds. In this "world class" coalfield, there are at least 13 other persistent, 3 to 15 m (10 to 50 ft) thick, coalbeds as well as the Big George and Lake De Smet coalbeds, which are each 61 m (200 ft) or more thick in places. None of these latter 13 coals are mined at this time.

Jan 1, 1994

By J. R. Caylor

The Mine Safety and Health Administration (MSHA) advanced several initiatives last year to further protect miners' health. Regulatory efforts included the implementation of a Hazard Communication rule for all mines, work on the Single Sample rule for all coal mines, and the Plan Verification rule for underground coalmines. Development and application of new technologies are actively encouraged in preventing miners' hearing loss and respirable dust overexposures. MSHA's successful x-ray program for screening of black lung among coal miners completed its third year. Compliance Assistance efforts are focused on Best Practices, outreach, and technical support for operators' specific challenges.

Jan 1, 2003

By Patrick McElhinney, Jacob Carr, Bruce Whisner, Cory DeGennaro, Jingcheng Li

Since 2016, electromagnetic interference (EMI) of personal dust monitors (PDMs) with magnetic proximity detection systems (PDSs) has been observed in underground coal mines. The EMI causes the magnetic field measurements of a PDS to change, which, in turn, alters the calculated location of the miner relative to the machine. Any altered location calculation can potentially cause the PDS to fail to warn a worker who is at an unsafe distance from the machine, arousing a serious concern on safety hazard caused by EMI in underground mines. The search for EMI mitigation strategies led to the development and use of large shielding pouches and boxes to hold the entire PDM to reduce its magnetic emission. Research on these pouches and boxes found that although they were able to reduce the emitted radiation from the PDM, they also disturbed the magnetic field of the PDS, affecting its performance. Researchers from the National Institute for Occupational Safety and Health (NIOSH) have focused on shielding internal PDM components rather than shielding the entire PDM. The PDM air pump motor is one of the PDM components that has been identified as a major source of electromagnetic radiation and has been selected for further study and tests. The measurements show that a small copper or aluminum foil enclosure can effectively reduce the magnetic emission of the motor by between 50 and 85% at 73 kHz. This study compares the test results of the air pump motor with various cost-effective shielding materials. The data provided in this paper can serve as a reference for shielding enclosure design of the PDM air pump motor to reduce its electromagnetic emission as one form of EMI mitigation strategy.

By G. A. Kosick, L. Kuehn

The design of an information management system (IMS) for a mineral processing plant requires prior consideration of many factors, which can be broadly categorized into two domains, process plant considerations and IMS considerations. The process plant considerations include: plant characteristics, management and personnel issues, existing organizational standards and policies, and the level of existing hardware and software systems. The IMS considerations include: system functionality, system sizing and desired performance, hardware components, software components, and system support issues. All of these aspects must be addressed in order to achieve a functionally successful and cost effective system. The purpose of this paper is to lay out these design issues and, in doing so, to provide process engineers with a guideline with which to tailor a system that is best suited to their specific application. The paper is completed by presenting an approach that has been used in two Canadian concentrators. Both of these plants have incorporated MillEX, a software system designed specifically as the central component of a mineral processing IMS.

Jan 1, 1993

By William T. Jr. Renfroe, Donald C. Gipe

INTRODUCTION Historically, pollution control in the metal-ore mining industry has been very limited. Unless mine water contained large quantities of solids, it was generally discharged without any treatment. If treatment was used to control solids, it was principally the provision of a settling basin in the form of a tailings impoundment used in conjunction with an associated metal ore dressing facility. Recently, however, a growing awareness of the adverse environmental impacts of mine drainage, coupled with strict environmental laws, has prompted the mining industry to look at new technologies and to refine the existing methods to further treat the wastes generated. This industry is unique in that waste loadings are extremely variable, and a "typical facility with typical waste loads" does not exist. Consequently, one waste- water treatment system cannot be utilized on an industry wide basis; rather, each treatment system must be designed specifically for the pollutants in each individual discharge. Public Law 92-500, the Federal Water Pollution Control Act (FWPCA) Amendments of 1972, became effective on Oct. 18, 1972. This law completely restructured Federal laws and philosophies underlying the Federal approach to water pollution control. Prior to the 1972 amendments, the principal Federal regulatory tool had been water-quality standards based on a designated use for a particular body of water. The concept was that waste disposal into water bodies is a desirable and acceptable use of the water body if it does not interfere with other beneficial uses. This had the effect of requiring various degrees of treatment and, consequently, various economic hardships on industries de- pendent upon their location. In many waterways. it is very difficult to quantitatively relate discharges to water quality. The 1972 amendments changed the basic philosophy, as stated in the Senate Committee report on the bill, to ". . . no one has the right to pollute . . . that pollution continues because of technological limits, not because of any inherent right to use the nation's waterways for the purpose of disposing of wastes." Pursuant to Sections 301, 304(b), and 306 of the FWPCA Amendments of 1972, the US Environmental Protection Agency (EPA) was required to establish effluent standards applicable to all industrial discharges. These standards must be based upon the application of the "best practicable control technology currently avail- able" (BPT) and the application of the "best available technology economically achievable" (BAT). The BPT and BAT levels must be achieved industry-wide by July 1, 1977, and July 1, 1983, respectively. WASTE SOURCES The waste-water situation in the mining segment of the ore mining and dressing industry is unlike that encountered in most other industries. Most industries (e.g., the milling segment of this industry) utilize water in the specific processes they employ. This water frequently becomes contaminated during the process and must be treated prior to discharge. However, in the mining segment, process water normally is not utilized in the actual mining of ores (exceptions are hydraulic mining operations and dust control), but it is a natural occurrence that interferes with mining activities and must be removed before mining can commence. Water enters mines by ground-water infiltration and surface runoff, and it comes into contact with materials in the host rock, ore, and overburden. The underground mine must pump large quantities of ground water to prevent flooding of the mine. Water from surface mining operations generally occurs as a result of surface runoff of rainwater. Generally, mining operations control surface runoff through the use of diversion ditching and grading to prevent, as much as possible, excess water from entering the working area. Nevertheless, some surface runoff does come into contact with the working area and may become contaminated. The quantity of water from an .ore mine is unrelated, or only indirectly related, to production quantities. De- pending upon its quality, the mine water may require treatment before it can be discharged into the surface drainage network. The variability of water quality from mines can best be demonstrated by looking at Table 1. This table shows the range of pollutant concentrations in untreated discharges from three different categories of mines (as categorized by EPA in the development of BPT and BAT effluent standards for the metal-mining industry). Data for this table were obtained during EPA's preparation of effluent standards for this industry. The parameters shown on the table are the pollutant parameters of primary interest in this industry; blanks in the table indicate that data were not available, and the parameter is not expected to be present in significant quantities. Other pollutant parameters are present in mining waste water, but they are either incidentally removed in the treatment process or are found only in trace amounts. The three categories comprise more than 90% of the metal production value in the United States and approximately 95% of the total mine discharges. It is important to note that not all parameters are found in significant concentrations at all locations. IMPACT ON WATER QUALITY One of the most troublesome mine-drainage problems is acidity. Although generally associated with coal mining, acid mine drainage frequently occurs from other types of mines. Although the exact mechanism of acid mine drainage is not fully understood, it generally is believed that pyrite (iron sulfide, FeS,) is oxidized by oxygen (Eq. 1) or ferric iron (Eq. 2) to produce ferrous sulfate (FeSO4) and sulfuric acid (H2SO4) . The mining of ores associated with pyritic material exposes the pyrites to water and oxygen and grossly accelerates the natural oxidation processes, resulting in the significant production of acid mine drainage.

Jan 1, 1982

Membrane technology has been available for over 36 years, but has been used sparingly in the general mining industry. However, recent developments in polymer chemistry, spiral wound element construction, pretreatment equipment and techniques and an expanded understanding of membrane fouling and cleaning techniques have dramatically improved the reliability and robustness of membrane based systems in the mining industry. Harrison Western has expanded the use of this “new” technology to enhance the use of membrane technologies to separate metals from large volume heap leach mining solutions containing copper, zinc, and iron, gold or silver. Moreover, membrane technologies are ideally suited to fractionations that add value to processing fluids from refineries like separating metals from acids or concentrating acids and producing high quality process fluids. Finally, wastewater from Acid Mine Drainage (AMD) or, as in the case of the Newmont Yanacocha Mine in Peru, the treatment of excess barren leach solution created during the rainy season, can be cost effectively processed to meet World Bank Standards for surface discharge. Polymeric membranes, specifically thin-film composites, have been developed that will purify, fractionate or concentrate gold, silver, copper, zinc or nickel. Recent applications have been developed for spiral wound modules that operate across the pH spectrum from 0 to 14. Systems using membranes have been constructed that operate on feed streams from 140° C to 300 centipoise. Opportunities exist to apply membrane technology to concentrate gold, silver, copper, zinc or nickel using thin film composite membranes. Engineered membrane types can operate across the spectrum from low pH (<2) acid applications to high pH > 10 cyanide applications. Incorporating HW EMS™ membrane technologies into current mining operations could allow one to increase production because the membrane technology would be used to pre-concentrate heap leach solutions, and therefore, increase utilization of existing extraction and refinery capabilities.

Jan 1, 2007

By M. Leslar

Slope monitoring has been an important issue in static terrestrial lidar for some time. Several solutions for monitoring the progress of a slide have been devised over the years. All of these solutions have required users to be in the field operating the lidar equipment. This paper presents a new system developed using the Optech ILRIS-HD or ILRIS-LR lidar and the scripting language of PolyWorks to produce an autonomous slope monitoring system. This system has proven invaluable in detecting and alerting mine workers to potential danger within their mine sites. It has already been deployed in two mine sites and is scheduled to be installed at a third.

Feb 27, 2013

By R. Curtis

To achieve compliance with 2015 EPA Tier 4 Final regulations, which permit only around 10% of Tier 3 particulate matter (PM) and NOx emissions, a number of technologies are being implemented. Use of a fuel borne nanoparticle combustion catalyst reduces the level of PM and unburned hydrocarbons exiting the combustion chamber, alleviating the burden on downstream exhaust after-treatment systems. The impact of an iron-ceria combustion catalyst (GO2) on carbon oxidation kinetics and on diesel engine emissions is presented. The iron-ceria nanoparticles catalyze carbon oxidation at lower temperatures and increase the oxidation rate by a factor of 18 at 400 °C. Engine tests on a generator powered by a John Deere Model engine and field tests on a Cummins ISC 330 tractor truck and CAT 3508B propulsion engines are presented. Use of GO2 resulted in a reduction in PM10 (particulate matter under 10 um) emissions of up to 26% and a hydrocarbon emission reduction of up to 41%. NOx emissions did not increase in these trials and the amount of change depended on engine type. Application of this fuel borne technology for emissions reductions in mining equipment offers significant benefits.

Feb 27, 2013

By M. P. Fahey

A significant amount of silca is recovered in the rougher stage of anionic flotation of Florida apatite. This recovery, in the past, has been attributed to both entrainment and cation activated flotation. This study shows that by using a transport factor, it is possible to determine the contribution of each mechanism towards silica recovery. Further, it is shown that the concentration of cations in the conditioning water significantly affects both the amount of silica recovered due to entrainment and true flotation. Further confirmation of this phenomenon was obtained by Ca++ doping of the conditioning water and by using a sodium silicate depressant.

Jan 1, 1996

By S. Underwood

The tracer gas method of conducting ventilation surveys is a means of determining air quantity in underground mines with knowledge of the concentration of the tracer in the atmosphere and the flow rate at which the tracer is being released. The technique is useful in inaccessible areas of underground mines and areas where traditional point measurement of velocity is not practical. Sulfur hexafluoride (SF6) is the industry standard tracer(Kennedy 1987) used in underground mines because it is safe, stable, and not naturally occurring in the mine environment. The implementation of a second tracer will increase the versatility of the tracer gas technique allowing for simultaneous releases for the study of interrelated ventilation circuits, and for conducting multiple experiments in less time. This paper will detail the selection of perfluoromethylcyclohexane (PMCH) as a novel tracer with sensitivity, physical properties, and analysis characteristics similar to SF6. Methods for the release of liquid PMCH into underground mines will be recommended, and the vulnerabilities of sample loss due to condensation of vapor PMCH will be explored. Finally, the benefits and implications of using PMCH as a second tracer will be discussed.

Jan 1, 2012

By Milan Yekich, Emanuele Cauda, Justin Patts, Cody Wolfe

This study presents the application of low-cost dust monitors (LCDMs) for real-time monitoring of respirable dust in a mining environment. LCDMs significantly enhance data collection by providing continuous, granular and cost-effective dust concentration readings. This case study demonstrates that by deploying LCDMs, mining operators can respond quickly to changes in dust levels, improving occupational safety and air quality management. The results show how such monitoring technologies can be integrated into routine operations to reduce dust exposure and prevent health hazards such as silicosis, especially when coupled with appropriate mitigation strategies.

Nov 1, 2024

By Juan P. Camus

One of the most important decisions in mine development is the selection of the mining method. Open pit or underground methods are selected depending on the shape of the deposit, and its position with respect to the surface. When the decision is not clear or evident, then the common rule is to compare underground and open pit projects to choose the one which yields the maximum return. However, in some circumstances&apos; the best alternative is to start-up the operation with an open pit until a point where mine operating costs make more convenient to employ an underground method. In this case, the final pit limit is not directly related with commodity prices and its position is a funtion of capital and operating costs associated with both methods. The goal of this paper is a mans of establishing the proper ultimate pit considering a potential underground mine. The methodology is quite simple and can be implemented to work with a variety of available routines for pit optimization, such as Lerchs-Grossmann, floating cone, network flow and the Lemieux moving cone optimizing algorithm, which is the tool used by the author.

Jan 1, 1992

By A. Jahedsaravani, M. Massinaei, M. H. Marhaban, N. Mehrshad, M. I. Saripan

"It is well known that froth visual features reflect the operating conditions of the flotation process, so that being able to accurately obtain the froth properties is the most significant criteria to optimize and control this process. Froth segmentation is a useful procedure that can determine the bubble size distribution. Several algorithms have been proposed in this field, but marker-based watershed transform shows the best performance. In spite of this fact, the algorithm suffers from oversegmentation in cases when the flotation froth includes large bubbles along with small ones. In the paper, the marker-based watershed method is modified to prevent oversegmentation of large bubbles. The developed algorithm is validated using some froth images captured at different operating conditions, so the results indicate that the method can segment the mixture of big and small bubbles effectively.IntroductionFroth flotation is a widely used process for separating valuable from gangue minerals. Effective control of flotation circuits has a dramatic effect on overall performance of a mineral processing plant. In most flotation plants, process operators monitor the froth surface visually and make adjustments to process parameters based on their interpretation of the surface appearance and their idea of the appearance of an ideal froth. However, due to natural complexity of the flotation process, achieving optimal control is often not possible for human operators.In recent years, attempts have been made to control the flotation circuits using machine vision systems (Moolman et al., 1995; 1996a,b; Bartolacci et al., 2006; Kaartinen et al., 2006; Vanegas and Holtham, 2008; Aldrich et al., 2010). The froth bubble size distribution is the most significant control variable that reflects the operating conditions in a flotation machine. To date, a number of approaches have been proposed for bubble size measurement from froth images, including segmentation (Sadr-kazemi and Cilliers, 1997; Wang et al., 2003; Mehrshad and Massinaei, 2011), texture spectrum (Nguyen and Thornton, 1995), wavelet (Liu et al., 2005), an improved texture spectrum approach, a method based on binary images (Lin et al., 2008) and, finally, using interfacial morphological information (Yang et al., 2009)."

Jan 1, 2015

By Eugene F. Casey

As indicated on the official conference program, this presentation in not a formal one, but a synopsis of the activities of a newly created Sub-committee of the Research Council on Underground Construction, which involves itself with small diameter tunnels. Because there is a dire need to develop a system of excavating small horizontal openings at shallow depths without interrupting traffic, it was hoped that a more progress report could be reported at this time. Because of ecological and environmental considerations, laws are being passed which mandate that all utilities be placed underground. In urban areas the excavation of trenches in which these utilities are placed has been done by disrupting the normal flow of traffic, thereby creating complete chaos. In addition, it always seems that the Companies involved have no coordination, since one company completes its installation and another one begins. Certainly, utility tunnels can be driven at greater depths to house main feeder and trunk lines, but there still remains the problem of installing distribution lines for house services. The definition of a "mini" tunnel, is a tunnel whose excavated size is approximately 48 in. or less. The objectives of the Committee are to "stimulate the development of systems and equipment to build tunnels in these size ranges which will reduce costs, time and surface disruption from current systems."

Jan 1, 1974