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By Robert W. Elayer

For the design of a coal mine and process plant, a comprehensive foundation of geologic information is essential. Historically, the development, collation, and use of this information for design have been costly and time consuming. With the application of a digital computer, however, the effort expended can be reduced and maximum effective use of the geologic information realized. The purpose of this paper is to demonstrate the feasibility and convenience of using a computer to Store and manipulate geologic data for use in mine and process plant design.

Jan 1, 1975

By L. Zhou, D. Bahrami

Mine ventilation is one of the most important aspects of mining operations in underground mines. It is critical to maintain and deliver required fresh air to the active areas to reduce the risk of overexposure to hazardous contaminants or explosive atmospheres. An unexpected or unknown event such as roof collapse, unexpected mine door closure/opening, a fire/explosion, or fan malfunction could adversely alter the airflow distribution within the mine ventilation network that could lead to a hazardous underground environment. Knowing the occurrence and location of such an incident is of critical importance. In this study, the authors developed a novel methodology to assist mine operators in quickly identifying the location of any abnormal airflow change within the network using the airflow changes at monitored airways. The concept is based on a direct derivative method developed by the authors. This paper provides the details of the developed method as well as numerical verification examples. The application of this method can benefit mine operators and safety personnel in making better decisions during a mine emergency response operation to mitigate hazardous conditions arising from an unexpected airflow disturbance

Mar 2, 2022

By Daniel Hodouin

Artificial neural networks (ANN) are of growing interest in a wide variety of applications. Pattern recognition, speech processing, financial analysis, signal processing and process control are at present the most successful ones. This paper is an attempt to illustrate the potentiality of ANN applied to mineral processing. An introduction to the technology of ANN is first proposed to describe the various components and to explain the various phases encountered in setting up a network. Then examples are given to illustrate the use of ANN dynamic modelling of mineral processing units or plants and in process control.

Jan 1, 1991

By H. Y. Yang, L. L. Tong

Semicontinuous-flow, multistage biooxidation experiments of a Chinese refractory, high-sulfur gold concentrate were conducted with different pulp densities for gold recovery. The maximum iron, sulfur and arsenic oxidation rates of 90.0, 88.8 and 96.4 percent, respectively, were obtained in the experiments with 5 percent pulp density. The highest gold and silver recoveries of 96.1 and 68.9 percent, respectively, were achieved by cyanidation. The negative effect of high pulp density on biooxidation was related to the decrease of free and adsorbed cell concentrations with increasing pulp density. The data of iron oxidation from the semicontinuous biooxidation experiments were best fitted by a shrinking core model in which the chemical reaction controlled the rate. The dissolution kinetics of sulfur and arsenic were therefore analyzed by a shrinking core model in which the internal diffusion controlled the bioleaching rates. For the quantitative description of biooxidation efficiency, two parameters — mass dissolution rate and volume dissolution rate — were proposed. In the first stage, the mass dissolution rates of minerals were negatively correlated while the volume dissolution rates were positively correlated with the actual pulp density. The iron and sulfur mass dissolution rates decreased with increasing actual pulp densities in the third and fourth stage, while linear increasing relationships between the volume dissolution rates of minerals and the actual pulp density were observed from the second to fourth stage. The highest mass dissolution rates of minerals were obtained in the first stage with 5 percent pulp density. The highest volume dissolution rates of minerals were obtained in the first stage with 15 percent pulp density. Compared to the volume dissolution rate, the mass dissolution rate was more intuitive to reflect the negative effect of high pulp density on biooxidation efficiency.

By E. H. Bentzen

The purpose of this paper is to explain the production of sand for glass manufacturing and the reasoning behind the sand specifications set by the glass industry. In order to discuss the production of glass sand, there is a need to understand what glass is and how it is made. Therefore this paper discusses glass, as well as sand beneficiation.

Jan 1, 1977

Introduction The art of ripping has been around since the Romans built the Appian Way, but only in the last decade has ripping emerged as a close competitor with drilling and blasting in breaking up heavy rock formations. That is not to say ripping is as effective in every case, or even applicable in all cases, but it does provide a cost efficient option in many situations-if the optimum ripping techniques are used. Originally designed only to loosen hard pan, the ripper has evolved into a powerful tool, its capability increasing as the weight and horsepower of tractors increased. The tractor-mounted ripper extended the range of ripping because of the additional weight it brought to bear on the ripper tooth. Tandem ripping added the weight and power of a second tractor, extending the rippability range even further. Of course, the use of ripping depends on the type of material to be ripped. Not all rock can be ripped. Determination of rippability-an art in itself-is often inconclusive but there are certain universal principles that can be considered in the first step toward optimizing ripping techniques. Each of the three basic rock types, igneous, sedimentary, and metamorphic, exhibits characteristics that bear on rippability. Igneous rocks are the most difficult to rip because they lack the stratification and cleavage planes essential to ripping hard rock. Sedimentary rocks are generally the most easily ripped since they are built of layers differing in material, texture, color, and thickness. Metamorphic rocks vary in rippability with degree of lamination or cleavage caused by transformation from pre-existing rock. The condition of rock also affects its rippability. Although sedimentary rocks offer the best opportunity to rip and igneous and metamorphic the least, decomposed granite and other weathered igneous and metamorphic rock often can be ripped economically. Little or no trouble is encountered with hardpan, clays, shales, or cemented gravel. Likewise, highly stratified or laminated rocks offer good possibilities for ripping. However, thicklybedded rock formations generally must be drilled and blasted. The physical characteristics that favor ripping may be summarized as follows: • Fractures, faults, and planes of weakness of any kind; • Weathering, resulting from temperature and moisture changes; • Brittleness and crystalline nature; • High degree of stratification or lamination; • Large grain size; • Moisture permeated clay, shale, and rock formations; and • Low compressive strength. Ripper Types A second fundamental to optimal ripping is choosing the right equipment for a particular job. There are three types of rippers-the hinge, the parallelogram, and the adjustable parallelogram. In the hinge ripper the linkage carrying the beam and shank pivots on a fixed point at the rear of the tractor. The resulting arc from up and down movement causes up to 30° differential in the tip-ground angle. Thus, the tooth angle changes as it enters and proceeds to ripping depth. The parallelogram ripper's linkage maintains the same tip-ground angle regardless of tooth depth. This type of ripper has advantages over the hinge-type when ripping above maximum depth, but does not provide the aggressive tooth angle necessary for hard-to-penetrate materials. The adjustable parallelogram combines the benefits of both the hinge and the parallelogram rippers. It has the additional benefit of being able to vary the tip angle to the optimum angle of penetration. It can also be adjusted while moving, for the optimum ripping angle in any material. Several other factors that are important in selecting the right ripping equipment are down pressure available at the tip of the ripper, tractor flywheel horsepower, and the tractor's gross weight. Down pressure at the tip determines whether ripper penetration can be obtained and maintained. Flywheel horsepower rating determines whether the tractor has the power to advance the tip. The tractor's gross weight determines whether the tractor will have sufficient- to use the horsepower. The best ripping procedure depends on the job's actual conditions. While conditions, vary, it is still possible to apply certain proven techniques to a typical ripping situation. Caterpillar Tractor Co.'s Handbook on Ripping says optimum ripping efficiency can be realized if-before actual ripping begins-these questions and answers are considered.

Jan 1, 1983

By H. Hinds

Plant testing of DuPont's Activator Technology in the vat leach circuit of the Homestake mine shows increased gold recoveries of 3-5%. Activators are catalysts of gold dissolution in cyanide solution. DuPont received the patent for this technology in January, 1996. The test was run in the west sand plant alternating control and activated vats to reduce the variability in head grade and cyanide consumption. Activated vats had gold in the preg solutions earlier, higher gold recovery, and lower gold residuals. Activator addition did not adversely affect mill operations or the environment. Optimization of the technology continues.

Jan 1, 1997

By William T. Ingram

Early in the 60's the author served as Chairman of the Engineering Foundation's Coordinating Committee on Air Pollution Research. One of our objectives was the development of a study on the measurement of stack emissions. Three publications of the Foundation resulted from these efforts to focus attention on the stack sampling problem.1,2,3 Two of these were annotated bibliographies covering 197 references. The third reported the results of a workshop meeting at which some 21 individuals from research institutes, industry and government discussed the possible and probable areas of research that would add to or increase the ease, precision and utility of sampling gaseous and particulate matter emitted from stacks. The American Society of Mechanical Engineers has had in its Power Test Codes a Standard Code for Determining the Dust Concentration in a Gas stream4 since 1941, The American Industrial Hygiene Association has published, in its Air Pollution Manual,5 a Section on Stack Sampling. Industry and regulatory agency requirements for stack sampling have utilized some modification of the alternatives in methodology. There has been ho single guide to stack sampling that met the needs of those who have the need to know.

Jan 1, 1970

By Jon Kellar, Samuel Kessinger, Prasoon Diwakar

Tantalum (Ta) and niobium (Nb) are extracted from many different ore types. The major economic orebody mined for tantalum and niobium consists of tantalite ((FeMn)Ta2O5) and columbite ((FeMnNb2O5)) in a solid-solution mineral commonly referred to as “coltan.” The largest supplying region, The Democratic Republic of the Congo (DRC), is unfortunately also the most ethically compromised source for this critical mineral. Officially, the U.S. government has deemed coltan ore from the DRC a “conflict mineral” [1]. The lack of pragmatic and effective local mining regulation in Central Africa, when coupled with high levels of violence and corruption, has spawned a widespread, illegal, unethical and, most importantly, unsafe economy. This illicit economy is centered around first, illegally mining these valuable conflict minerals and second, smuggling these minerals into the global supply chain. Handheld spectroscopy devices could provide further transparency to these opaque supply chains, giving miners, traders and refiners the ability to authenticate the provenance of the minerals they encounter, and allowing companies to prove compliance with the regulatory agencies attempting to curtail illicit mining.

Mar 1, 2025

By Charles E. Mauk

In 1970, recognizing the great need for an economical, high capacity chemical oxidation process for wastewater treatment, Houston Research began a fundamental study of the available technology, Included was waste characterization; oxidation chemistry for molecular oxygen, ozone and catalyst initiators; kinetics of reaction; gas-liquid contacting methods; and optimization of staged reactors for mixed wastes. Although ozone is the most powerful oxidizer available, the literature contains contradictory reports of its speed and effectiveness. It is now felt to be most likely that many of these early investigations were limited by the ineffectual transfer of ozone from the gas phase into the liquid, and so the investigators were really observing the effects of mass transfer and erroneously trying to interpret the results as if they were chemical reaction data. HR's work considered the cost and effectiveness of gas-liquid contacting in a packed tower, gas sparged contactor, ejector with hold-up tank, and a completely mixed, sparged contactor. The sparged, mixed contactor was found to be most effective and least expensive, and a later investigation settled on the reactor configuration shown in Figure 1 because of its effectiveness of mass transfer and because it lends itself to direct scale-up techniques using laboratory data to design larger reactors.

Jan 1, 1975

By Donald J. Reining

The California Surface Mining and Reclamation Act (SMARA) is the nation's first legislation establishing a statewide mineral resource policy governing mining activities that recognizes regional needs and retains local autonomy. The Southern California Rock Products Association supported this proposed legislation. It was through our efforts that SMARA was passed in 1975. The local planning and zoning processes, which are so critical to the mining industry, have been significantly improved with implementation of SMARA. Recognition of the importance of the mining industry is now being developed by the State Mining and Geology Board and the California Division of Mines and Geology (CDMG).

Jan 1, 1984

By Roshan B. Bhappu

Based on the classical definition of optimization, flotation plants of today are far from being perfect, effective, or functional as possible. Though considerable efforts have been expanded in the optimization endeavor during the last decade, much more needs to be done in the future to optimize our flotation plants and operations. The major problem in designing an optimum flotation circuit is that the flotation process depends on the interaction of several physical and chemical parameters. In the past, there has been a tendency to only consider the effects of chemical factors such as flotation reagents: collectors, frothers, conditioning reagents, pH, etc. On the physical side, the emphasis has been limited to the liberation characteristics, grinding time, percent, solids in the pulp and flotation time. Its only recently that we are employing particle size analyses, on-stream analysis, oxidation reduction potential and the like, as operating controls. The design, operation and control of a mineral processing plant depends on costs incurred at all stages, from inception (testing for flowsheet development) through plant closure and beyond. To ensure that micro- and macro- engineering technology is transferred to operational levels, the academia, testing engineers, designers, operators, consultants and management must all get involved in the transformation process. Historically, in the 1950’s engineering empiricism was strengthened through micro-engineering based on fundamental and mechanism. Unique scientific apparatus such as zeta meter and infrasizer were used to test new hypotheses. With the advent of computers in the 60s and 70s, complex differential equations were solved to study and understand unit processes and to assess mechanism assumptions. Such efforts contributed to improved understanding of the unit operations such as comminution, flotation, thickening, filtration and the like. In the 80s and 90s with the availability of more sophisticated computer technology involving modeling procedures, advanced numerical methods, image analysis, nonlinear-curve-fitting and data adjustments, it was possible to test newly developed models under the production environments. These innovations are now available to develop simulator and sensors (such as particle size analyses) for macro-engineering purposes including plant design, automatic controls and optimization. Accordingly, it behooves the mining companies and plant operators to take advantage of these new developments to control a large number of physical and chemical parameters involved in the plant operation and optimization. This is especially important in light of declining head grades and increasing operating costs in the U.S. minerals industry if it wishes to maintain a competitive edge in the international marketplace. In regard to the future R & D activities in the field, in order to arrive at useful correlations in micro- engineering research, it is essential to consider a plant operation as an interactive engineering system representing the combined effects of physics and chemistry, equipment and operation. The important issues that needs to be addressed in the future are

Jan 1, 1993

By Tyler Acorn, Brandon Wilson, Jeff Boisvert

Project-scale decisions in surface mining operations rely on the optimization and subsequent evaluation of pit limits. This process ignores the ability for mine plans to adapt as more information is gathered. Stochastic methods, which consider uncertainty in the pit optimization, generally act to refine the boundaries of the pit on a fine scale. This paper extends uncertainty-based methods to consider unique scenarios through a clustering of the realizations that are being optimized. This results in the generation of multiple sets of similar realizations. A separate pit is optimized on each set of realizations, resulting in the production of a series of planning scenarios. This accounts for the adaptability of mine planning as more information is gained. A decision-making framework is then applied to the resulting scenario plans to select the optimal choice. The improvements stem from the joint uncertainty considered when realizations are grouped that is not considered when the probability of a block being in any optimized pit is considered. Mining operations today can benefit from considering additional planning options as identified and evaluated in this workflow.

By J. G. Pippenger

The Coteau Properties Company's Freedom Mine is a surface lignite mining operation located near Beulah, North Dakota. Coteau, a wholly owned subsidiary of The North American Coal Corporation, produces more than 13.5 million tonnes per year, ranking it among the largest mines in North America. In 1993, Coteau ranked seventh in terms of annual coal sales, becoming the largest mine outside the Powder River Basin of northeastern Wyoming. However, for the Freedom Mine to stand among these Powder River heavyweights, Coteau over-came several obstacles, including a coal seam with three quarters the heating value and overburden to coal ratios three times higher than the Powder River mines. Coteau's ability to compete has been built around a program of continuous productivity improvement, cost efficiency, and innovation. This report highlights a few of the major improvements implemented in recent years.

Jan 1, 1995

By Craig M. Sams

Dry grinding circuits and factors influencing the selection of the most appropriate grinding system for a given ore selection are discussed. Comparisons of the drying, grindability, installed costs and operating costs are presented for several grinding systems.

Jan 1, 1994

By Charles H. Ricker

Simulation models have been widely used to analyze the operations and characteristics of a variety of systems. Such models mimmick a projected reality by analyzing the interaction of the events, transactions, and facilities which combine to make up the system. The models are structured as a computer representation of the system components and their logical, precedence and timing relationships. The operation of the system is then simulated over some finite time interval to gather analytical and staistical data. This paper presents a method whereby bulk handling systems, either actual or proposed, may be analyzed by means of simulation models to project the enconomic consequences which may be expected from the system over some future time interval. An example is given to illustrate the construction of bulk handling simulation models, the derivation of performance data, and the analysis of the information with an eye to effective decision making.

Jan 1, 1974

By G. W. Luxbacher

With the advent of acid rain legislation included within the Clean Air Act Amendments of 1990, a great deal of uncertainty with regard to price, source and production quantities has been cast into the coal market. Powder River Basin and other western coals continue a rapidly accelerating migration eastward, South American coals move into the northern markets, states propose legislation to assist utilities in complying with the new regulations in hopes of maintaining their own coal industries, while some utilities question the long term availability of eastern compliance coal. Any major coal producer must make decisions now to assure their continuing presence in the market place; several companies have adopted a strategy to acquire eastern compliance reserves while others have invested in technology to compete as a low cost producer. This paper discusses some of these options in light of the uncertainties of the market place, from an eastern coal producer?s viewpoint.

Jan 1, 1992

By Rebecca Boakye, Zohreh Kazemi Motlagh, Virginia T. McLemore

The most significant uranium (U) deposits in New Mexico are sandstone-hosted deposits in the Morrison Formation (Westwater Canyon Member), where >169,500 short tons of U3O8 were produced from 1950 to 2002. In addition, >9076 pounds of vanadium (V, a critical mineral) and some molybdenum (Mo) were produced from these deposits. These and other U deposits (limestone-hosted, U-veins) in New Mexico also contain critical minerals. Critical minerals are mineral resources that are essential to our economy and whose supply may be disrupted; many critical minerals are 100% imported into the U.S. Some sandstonehosted, limestone-hosted, and U-vein deposits are elevated in heavy rare earth elements. One sandstone-hosted sample contained 0.3 ppm Re (critical mineral), 659 ppm Se and 408 ppm Mo. The arsenide five-element vein deposits in the Black Hawk district are mineralogically and texturally complex, low- to moderate-temperature, hydrothermal, structurally-controlled, Ag-Co-Ni-Bi-As bearing carbonate vein systems with local minor elements. Mineralized samples from Black Hawk contain up to 9970 ppm Ag, 8540 ppm As, 5690 ppm Co, 72,400 ppm Ni, 57 ppm Bi, 165 ppm Sb, and 32,600 ppm U.

Feb 22, 2026

By William Gleason

"Once the primary fuel source for the United States and the economic backbone for communities from Appalachia to Wyoming, coal has been on a steady decline since the mid 1990s, and is now at the center of political debate in the United States.The political spectrum of the United States is divided on the future of coal and its place in the energy sector. The coal mining industry and the communities that rely on coal have increasingly been pitted against forces that wish to regulate coal to the history books.In 2008, President Obama launched what many have called his war on coal, and during his eight years in office, he pushed through numerous pieces of regulations and legislation and that he said were aimed at reducing carbon emissions, but that others viewed as direct assaults on the domestic coal industry. Obama led the United States delegation to Paris to sign the Paris Accord in 2016, a 196-country agreement pledging that the United States would do its part to reduce carbon emissions. His administration also instituted clean air, power and water regulations that added extra environmental burdens to many industries, but perhaps none more so than the coal industry.In this month’s lead feature, “A study of U.S. coal mine closures since 1994” (page 18), the impact of the war on coal, and other factors, can be seen in text and figures. Author Jacob Brinkman and coauthors Jay Schafler and Catherine Johnson scoured the data of the U.S. Energy Information Administration (EIA) and the U.S. Mine Safety and Health Administration (MSHA) to show how coal production and mines have been impacted since 1994 and how the years 1994 to 2000 and 2008 to 2016 were particularly hard on the industry.For example, in 1994 there were 2,354 coal mines in the United States. Currently, there are 1,035 mines in operation.In 2016, then candidate Donald Trump promised to end the war on coal and to put coal miners back to work. In 2017, President Trump has followed up on those promises. He announced plans to withdraw the United States from the Paris Accord, signed an executive order designed to undo the Clean Power Plan put in place by President Obama, halted the research on the health effects of mountaintop removal coal mining, directed the U.S. Environmental Protection Agency (EPA) to revise the guidelines of waste water from power plants and has touted that more than 1,000 coal miners have returned to work since he was elected."

Jan 9, 2017

By C. Mark, D. M. Pappas

From 1999 through 2008, groundfall events resulted in 75 fatalities, 5,941 injuries and 13,774 noninjury roof falls in U.S. underground coal mines, according to the U.S. Mine Safety and Health Administration (MSHA). A comprehensive analysis of these events was conducted to better understand where and why these incidents occurred. The first segment of the study used the MSHA database to evaluate groundfall injury rate trends related to mining method, year, locality, seam thickness, mine size, coalbeds and seasonal effects. In the past decade, roof fall injury rates have dropped 50%, but rib fall injury rates have remained constant. Room-and-pillar mines had a roof fall injury rate that was nearly 2.5 times the longwall rate. High groundfall rates occurred in the Illinois Basin, a finding that correlates with other studies that have shown that roof rock in the Illinois Basin is weaker than that in the central Appalachian coalfields. Finally, noninjury roof fall rates in the eastern and central United States were found to be 50% higher from July through September, possibly because of the changes in humidity levels that may cause shale mine roofs to deteriorate. The second segment of the study evaluated the root causes of failure by reviewing all MSHA groundfall fatality reports for 1999-2008. Pillar recovery was the leading cause of groundfall fatalities (19%), followed by rib falls, roof skin falls and traveling under unsupported roof (16% each). Defining prominent ground control incident trends and hazards will identify areas where additional study is needed and where innovative solutions need to be developed to reduce these severe occupational hazards.

Jan 1, 2011