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By David Akers, Clifford Raleigh, Glenn Shirey

Under a Cooperative Agreement with the U.S. Department of Energy’s National Energy Technology Laboratory (NETL) and the Mining Industry of the Future Program, CQ Inc. is demonstrating the GranuFlow™ process for improving the recovery of fine-sized coal in commercial coal preparation facilities. The State of Pennsylvania’s Energy Harvest Grant Program is also providing funding for this project. The GranuFlow technology involves the addition of an asphalt emulsion to a slurry of fine-sized coal (<100 mesh or 0.15 mm, typically froth flotation concentrate) before mechanical dewatering in screen-bowl centrifuges. The emulsion selectively agglomerates the carbon-rich particles, resulting in increased particle size and improved recovery of the coal fines during the dewatering process. This paper summarizes the test conditions and current results for both bench-scale investigations and full-scale commercial plant demonstrations.

Jan 1, 2005

By E. S. Peterson, M. K. Harrup, K. A. Dolbeare, J. E. Wey

Efficient methods for the removal of copper from heap-leach solutions without mobile organic phases are a current mining industry need. To satisfy this need, a selective, high-capacity, durable solid material is required. The Idaho National Engineering and Environmental Laboratory (INEEL) developed a set of materials based on current solvent-extraction chelates that provide selective copper concentration in the presence of high concentrations of iron. In contrast to conventional solvent extractions, the author&apos;s strategy anchors the chelators to a nonpolymeric solid substrate through the use of a custom-designed linker molecule. The fundamental synthetic routes to these materials have already been established, and attachment to the solid surfaces have been achieved in an efficient manner. The author&apos;s continuing research is focused on the optimization of the synthetic pathways to these solid materials and the evaluation of their copper-capturing capabilities.

Jan 1, 2003

By Wojciech Suwala

The transition from centrally planned to market economy affects methods of economic analysis. The models which were used in the past are riot valid presently, however they we&apos;re the seed which initialized the development of methods and applications. There is more than twenty years of experience in modeling of coal mining development. The first attempts were devoted to select the moment of mine construction commencement in order to meet planned output. In Poland significant development of such models began in 1986. Within the Central Research and Development Program there has been a continuous development of models. These models from econometric to optimization ones, were a certain sequence which, in accordance with changing economy system, led to the last version of the model. It is the most suitable one for contemporary problems of coal mining in present Polish circumstances.

Jan 1, 1992

By A. D. Davis, C. J. Webb, F. W. Beaver

The proposed National Underground Science Laboratory will be housed in the former Homestake Gold Mine at Lead, South Dakota. Uses will include underground neutrino experiments that must be shielded by several thousand feet of rock, as well as ground-water research in fracture-flow environments, and investigation of the microbiology of extreme environments. The Homestake Mine has about 300 miles of underground workings. Seepage of ground water into the mine openings is approximately 500 gallons per minute. Average annual precipitation in the northern Black Hills is approximately 28 inches per year. The majority of this becomes surface-water runoff or evapotranspiration, with little ground-water recharge because of the low permeability of the Precambrian rocks in the area. Dewatering of the workings over the 125 years of operation of the mine has influenced the subsurface hydrology of the 8,000-footdeep mine.

Jan 1, 2003

By Kadri Dagdelen, M. Waqar Asad

Cement production involves the processing of raw materials that contain - Si02, A1203, Fe203, CaO, MgO, LOI (loss of ignition), S03, K20, Na2O, Ti02, P2055 and Cl- to produce the synthetic mineral mixture called "clinker". The use of other additives - sandstone, flyash, iron ore, and clay - is also mandatory in order to achieve the optimum blending requirements of cement. However, the use of these additives needs to be minimized due to their significantly higher costs ($/Ton). This paper presents a mixed integer programming (MIP)-based optimum quarry scheduling algorithm, which is used to generate quarry plans, satisfying geometric and production capacity constraints while providing minimum cost/optimum blend of raw materials mix to a cement plant. The benefits of this new methodology are demonstrated on a case study.

Jan 1, 2002

By J. B. Hiskey, V. M. Sanchez

Electrochemical oxidation of arsenopyrite (FeAsS) has been investigated as an attempt to gain a better understanding of its dissolution chemistry. Rest potential measurements, cyclic voltammetry and constant potential experiments were conducted in the pH range from 8 to 12 in the absence and the in the presence of cyanide. A two-step reaction sequence is suggested by the electrochemical measurements. The initial step is described by: [FeAsS+6H20=Fe(OH)3+H2AsO3- +S°+7H++6e] The second step involves the oxidation of the arsenite and sulfur according to the following reactions: [H2As03-+H20=HAsO24-+3H++2e and S° +4 H2O=SO4-+3H++6e] Stoichiometric determinations confirm that 14 electrons are involved in the overall reaction.

Jan 1, 1992

By G. F. Friel, J. C. Edwards, C. C. Hwang

In the implementation of a mine fire alarm and location strategy, the Interpretation of the fire signature Is Important. Smoke and CO are the two dominant fire signatures, and many mine fire detection systems utilize sensors which respond to smoke or CO through a diffusion mode or a mechanical pump mode. The fire signature may be modified during its transport along airways and at crosscuts. The modification occurs through dilution of the contaminants. In this Investigation, computer codes were employed to compute the effects of contaminant dilution on the contaminant signature when a straight flow passage has one dead-end crosscut. The model predicted the airflow within always and the entrainment of contaminants into the crosscut from the airway. One application of the model is to determine the most suitable location for CO detectors for early mine fire detection.

Jan 1, 1995

By Rudolf E. Greuer, Xintan Chang

Mine fires have always been of great concern to mining engineers and their behavior has been studied for a long time. Although an abundance of observations exist, no satisfactory mathematical model for their interpretation and extrapolation has become known. The paper presented here tries to close this gap, making use of the laws of chemical kinetics, energy and momentum conservation. To overcome the mathematical difficulties, the fire zone is axially divided into segments and radially into sections, each one with an extension of only a few inches. Conditions in segments and sections are updated in time intervals of one second or less. To solve the large number of resulting equations, a numerical solution is performed. The model has so far been tried on timber fires. It confirms experimental observations on the ignition phases and equilibria of these fires.

Jan 1, 1987

By Malcolm J. Lake, P. Brad Marchant, Linda M. Broughton

Thiourea is recognized as a technically competitive alternative to cyanide for gold and silver extraction for a variety of ores and concentrates. This paper describes the results of a recent mini-pilot locked cycle test comparing cyanidation with acidothioureation treatment of gold bearing sulphide concentrate. The gold extractability of both methods was similar. The comparative metallurgical operating conditions and test results are summarized. Detailed byproduct solution analyses and environmental toxicity test results are presented and suggest that thioureation might result in acutely toxic byproducts even after treatment. Comparative process economics are summarized based on preliminary commercial operating flowsheets derived for the locked cycle case study. Capital and operating cost estimates are shown. The results indicate that cyanidation is more economically favorable within the constraints of the case study. Considerations for process selection between thioureation and cyanidation, for conceptual case studies, are discussed.

Jan 1, 1998

By L. W. Laage

Throughout recorded history, underground fires have plagued mining operations. Compared with other hazardous situations in underground mining, a fire can become a global problem by swiftly spreading deadly carbon monoxide and other products of combustion (POC&apos;s) throughout the whole mine, often without warning. Experience has shown that when fires are detected and located in their early stages, they are much easier to control and proper escape routes can be more intelligently selected. Recent advances in sensor and data communication technology have made reliable mine fire .detection system installations possible. Unlike building construction. in a mine, it is impractical to install detectors at every desired location. Abandoned workings and unsafe locations preclude sensor installations from both safety and economic standpoints. The net effect is that some fires are detected and located early while the location of others, even if detected early, remains unknown too long for effective evacuation and fire fighting.

Jan 1, 1989

By E. Sarris

Tailings dams are large-scale earth-fill embankments that are designed to contain mining wastes from ore dressing plants. Most commonly tailings dams are constructed in stages in order to keep up with the increasing volume of mine tailings. Staged construction using various methods (like up-stream, down-stream, and centerline) is generally considered as a very effective way to construct this kind of embankments. The present study is devoted to the investigation of the behavior and the stability of these geostructures under static conditions. In order to accomplish this task, elaborate two-dimensional numerical models are examined, utilizing the geotechnical finite-element code PLAXIS. Numerical analyses are conducted for all three types of tailings dams in order to obtain the potential modes of failure, while the corresponding factors of safety are determined by the shear strength reduction technique.

Jan 1, 2005

By Robert L. Bonomi

One of the major operating costs for any labor-intensive operation is that of its employees&apos; wage and benefits package. Today&apos;s packages are extremely complex, with multiple pay rates for different grades and shifts, intricate bonus criteria, and expansive benefit packages that include all sorts of medical, dental, pension and other costs that can be "hidden" from direct examination and consideration. The problems of estimating the total cost of such a package to a company becomes even more acute at negotiation time, when pressure from both sides to settle intensify and changes to package offers come rapidly. A comprehensive system is needed that can evaluate these costs and perform sensitivity analyses, on the various components of an agreement so as to aid in the solving of major labor deadlocks, productivity problems, and cost impacts created by those agreements.

Jan 1, 1982

By T. E. Garnar

Heavy mineral mining has been a small, but important Florida industry over the past sixty years. Early geologic history of each deposit is similar up to point of deposition in alluvium, deltaic sediments, or along shorelines. Later geological development through reworking and concentration is different for each deposit. The Trail Ridge deposit was formed by reworking Citronelle sediments of the Lake Wales ridge. Post depositional leaching of iron from ilmenite makes Trail Ridge an important source of titanium minerals for TiO2 pigment manufacture. Research leading to the separation and sale of by-product heavy minerals from Florida deposits has been important in maximizing profitability. Advances in mineral dressing technology will lead to future mining of lower grade reserves. Future needs for heavy minerals seem certain to expand, with increased activity in exploration and development of mining operations.

Jan 1, 1972

By Steve Kral

Competition in the gold mining industry throughout the world has become fierce in recent years. The challenge facing operations personnel is to produce more gold for less money. Likewise, the explorationist&apos;s charge is to find more gold in a more cost-efficient manner. That means using new technology to find new gold deposits and expand present ones. More accurate mapping instruments are available to geologists in the search for new deposits. Advanced geophysical and geochemical methods enable explo¬ration teams to review previously mined districts in their search for minable reserves. Four technical sessions on the geology, exploration, and development of gold deposits were part of the program at `world Gold &apos;89,&apos; a Gold Forum on Technology and Practices," held by SME and The Australasian Institute of Mining and Metallurgy in Reno, NV, Nov. 5-8, 1989.

Jan 1, 1990

By Zhen-lu Zhao

The manipulators possibly used in underground mining must deal with unpredictable obstacle while keeping certain positions and orientations of end effector, and in some cases, are required to possess redundant joints in order to be more flexible. This kind of manipulators might be fitted with jumbo drill or platform as auxiliary to potentially deal with some utility works in versatile way, such as installing rock bolts, guniting, blasting, charging, surveys and measuring work, etc.. This paper describes numerical procedures of performing inverse kinematic problems for redundant manipulators .The procedures, based on the generalized pseudoinverse of Jacobian matrix, are developed to lead to kinematic solution at both singularity and ill conditioning, and to guarantee continuous sequence of positions of the end effect or. Furthermore, the solution to optimization and obstacle avoidance is investigated. A numerical example is shown to illustrate the approach.

Jan 1, 1989

By J. L. Hendrix, M. Ahmadiantehrani, G. Ramadorai

The concept of hypochlorite treatment prior to cyanidation in the heap leaching of low grade carbonaceous gold ores is discussed. Laboratory column leach tests using a low grade carbonaceous ore were performed to investigate the effects of pH, hypochlorite consumption and concentration, and bed height on total gold extraction. At high pH, hypochlorite stability increases and thus, hypochlorite consumption decreases. At room temperature, total gold extraction is proportional to hypochlorite consumption. However, at some point additional hypochlorite consumption does not increase gold extraction. Gold recoveries of 10% and 80% are achieved at 12 and 167 lb/ton hypochlorite consumption, respectively. Increasing hypochlorite concentration increases the rate of extraction. For a given hypochlorite consumption, gold extraction increased with decreasing ore bed height. Finally, using calcium hypochlorite results in higher gold extraction than using sodium hypochlorite at a fixed hypochlorite consumption.

Jan 1, 1992

By Henrique Garcia Pereira

In a large scale mining project, the global feasibility study must take into account the interdependence of three sub systems: the geological subsystem, represented by the orebody model; the technological subsystem, consisting .of mining and ore dressing models; and the economic subsystem, including the selling price of final product, production costs and investments. In cases where the ore is heterogeneous, the interdependence between geological and technological subsystems may be assessed by a Data Analysis technique such as Correspondence Analysis (CA). This technique was applied by David and Dagbert (1975) on examples of data from geochemistry and geology. In the approach used in this paper, CA is used to create the basic framework for defining different types of ore. The final definitions of ore types take into account the mi¬ning method and the results of applying beneficiation processes to the ore.

Jan 1, 1982

By Bart Hogeweg

The development of deep sea mineral deposits creates a new horizon for the mining industry. In a field where mining technology meets deep-water offshore engineering, new challenges are faced to come to the successful exploitation of these deposits. With the absence of proven technology for the mining of these minerals, a ?technological green field? is entered. IHC Merwede (IHC), a global market leader in the dredging and wet mining industry, is on the frontline of these developments. MTI Holland, IHC Merwede?s research and development company, has undertaken a number research efforts focused on the successful development of technology for the mining of deep sea minerals. This paper highlights a number of these efforts and illustrates IHC?s continued dedication for the research and development of technology to enable the commercial mining of deep sea minerals.

Jan 1, 2008

By B. K. Parekh

Silicon carbide (SiC) can be produced by heating rice hulls to elevated temperature, The product is a mixture of beta crystalline silicon carbide whiskers, particles and unreacted carbon. The silicon carbide whiskers are 0.5 micron in diameter and 50 to 100 micron in length and have been found useful for reinforcing metal and other composite materials. The carbon can be removed by combustion, but this makes separation of the silicon carbide whiskers from particles difficult and a high grade whisker product cannot be made. However, a clean high grade Sic whiskers product can be obtained from the pre-burned converted rice hulls using physical separation processes that are based on differential wetting. Recovery of Sic whiskers from the pre-burned material was found to exceed 90 percent. A modification of the froth flotation process developed during this study is now being used commercially to separate silicon carbide whiskers and particles and to recover a high grade whisker product.

Jan 1, 1985

By D. Marsh

The feasibility study for the Grasberg Block Cave mine, finalized in May 2008, indicated a production capacity of 160,000 tonnes per day. A rail haulage system was an integral part of the mine design. This paper describes the simulation process used in optimizing the design and discusses the key factors and variables that impact the capacity of the system. The final recommendations for the haulage level layout and associated equipment are also included.

Jan 1, 2010