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By K. T. Brashear, N. Ripepi

"Over recent years, specifically following the MINER Act of 2006, an increasing number of manufacturers of underground mine seals in the United States have begun using a form of pumpable cement or shotcrete to create barriers separating the working and abandoned sections of underground coal mines. This seal material, while generally considered to be homogenous and solid, contains a network of microcracks, voids, and delaminations. Generally, it has been assumed that methane (CF4) leakage around these seals is a result of movement around the boundary interface between the seal and surrounding strata. Using a perfluorinated tracer compound, perfluoromethyl-cyclohexane (PMCH), the movement of gases can be monitored through seal material to observe how gases move though the material, both intact and with faulting in the material. This paper documents two large experiments where the movement of PMCH was monitored in the field, along with modeling confirmation using 3D visualization software. INTRODUCTION According to a report in 2007, there were over 14,000 active mine seals in underground U.S. coal mines alone (Zipf, Sapko, & Brune, 2007). These seals are used for both ventilation and safety purposes, to direct the flow of air away from the abandoned area of the mine and to help eliminate the propagation of explosions that can occur on the outby side of the mine seal. The atmosphere on the outby side of these seals typical consists of low levels of methane that have the potential of producing leakage along the face of the seal on the inby side. Methane leakage around mine seals has historically been attributed to the permeability between the seal and mine interface (McPherson, 1993). According to the United States Bureau of Labor Statistics (BLS) between 2003 and 2012 an average of 17 deaths occurred annually in underground bituminous coals mines. The only time during the ten-year period where the fatalities were higher than the average was in 2006 and 2010, years which had three major explosions occurring in underground coal mines in West Virginia and Kentucky. Two of the explosions were propagated through the mine by seal failure or methane leakage around newly poured seals (Light, et al., 2007) (Gates, et al., 2006). These recent events, and new regulations regarding seal strength (MINER Act), have created a need to monitor the condition of underground mine seals. BACKGROUND Measuring the permeability of solid materials, such as concrete or seal materials, can be a valuable tool in the field of non-destructible testing (NDT). By using an inert gas, such as nitrogen, injecting the gas into a solid structure, and measuring the resultant flow rate and pressure differential, this can provide valuable information about the structure. Studies have shown permeability can be affected by the stresses applied to the structure, as well as temperature and moisture (Choinska, Khelidj, Chatzigeorgious, & Pijaudier-Cabot, 2007) (Abbas, Carcasses, & Olliver, 1999)."

Jan 1, 2015

By W. E. Bardelmeier

The high speed conveyor type self unloading bulk carrier concept has been around for about 70 years. Although the design was developed, refined and steadily improved in the Great Lakes, to date limited numbers of such vessels have emerged in the bulk ocean trades, and these have tended to concentrate within specific mineral trades. For example, North American gypsum companies have embraced conveyor self unloaders to the point where such vessels almost exclusively carry the gypsum requirements of this part of the world. One major aluminum company has developed an impressive fleet capability in self unloaders. Application of other ships tends to be fragmented through several mineral trades. A few years ago a new phenomonen began to appear on the Great Lakes. Whereas it had historically been accepted in that region that self unloaders were effective vessels for the minor bulk trades including limestone, coal, salt, gravel and sand; they had seldom been employed heavily in the big volume iron ore trades. Suddenly, however, the new generation of 60,000 ton Lakers which emerged were all designed as high speed self unloaders. The new vessels intended to trade especially in ore, or alternatively especially in coal, have somewhat different internal features, but the important point is that all are self unloaders.

Jan 1, 1979

By D. R. Zuchelli

The purpose of wrapping ball mills with thermal/acoustic blankets is twofold: 1) to maintain the desired temperature inside the mill, and 2) to reduce the sound emanating from the mill. This field case study focuses solely on the latter, evaluating and documenting the sound level reduction attributed to the installation of the blankets on ball mills and its potential to reduce the noise dose experienced by the process attendant. One of the three ball mills had already been treated (baseline) before the evaluation started. However, treating the remaining two mills still proved to be very effective, further reducing ball mill noise in the near field by as much as 10.0 dBA and producing far field noise reductions of 3.0 dBA or greater, extending as far as 35 feet from the mills and to the floor above. The model developed from the survey data shows that a process attendant spending a substantial portion of a shift in the mill building will experience a significant reduction in overall noise dose.

Jan 1, 2010

By C. McAllister, D. Preece, J. Berendzen

"The Multiple Blasthole Fragmentation (MBF) model models multiple explosive charge contributions and the effect on fragmentation of delay timing with its associated scatter for each blasthole. The model uses near-field blast vibration attenuation parameters and the ground p-wave velocity as inputs for part of the in situ rock property to model rock fragmentation. It models most blast design parameters explicitly and simulates the effect of wave reinforcement due to the interaction of simultaneously arriving waves or diminishing cooperative contribution from long delay intervals between charges within a blasthole or among blastholes. The fragmentation size is calculated at three-dimensional grid points within a blast, and the fines and oversized blocks are treated explicitly. The model takes a surveyed irregular geometry of the free face of a blast as the calculation boundary.This paper presents a case study on applying the MBF model at an openpit mine. Near-field vibration measurements from signature hole blasts were conducted to obtain the stress-wave magnitude and attenuation parameters as well as ground sonic velocity. A production blast was then monitored with the corresponding fragmentation measured, serving as site-specific inputs to the MBF model. Various blast design scenarios were then simulated to develop ones that provide better fragmentation to improve mill throughput for the mine. IntroductionThe semiempirical fragmentation models currently found in the literature (Cunningham, 1987; Lownds, 1995) cannot explicitly model contributions from multiple blastholes with varying delay intervals. Most of these models are not three-dimensional. Furthermore, these models predict an average fragmentation size within a volume surrounding a blasthole and use the average size to generate a size distribution over the volume. The percentage of fines and oversize blocks is included in the distribution. Typically, such models are inadequate for predicting fines and oversize blocks (Cunningham, 1987)."

Oct 1, 2016

By John E. Litz

Since the 1974 introduction of catalytic converters to automobiles in the United States, more than 150,000 kg (5,000,000 oz) of platinum, palladium, and rhodium have been used in the converters. An estimated 8 to 10 million converters are being used annually in the United States, each containing from $5 to $15 of PGM metals. In addition, use of converters is beginning in Europe which will significantly increase the quantity of PGM used. Two basic types of catalysts for converters are being used: pellet and monolithic. The pellets are small, discrete spheres or cylinders of gamma-alumina coated with platinum group metals, Figure 1. The monolithic are honeycombs of a cordierite, A13(Mg,Fe)2Si5AlO18, base coated with gamma-alumina and subsequently with platinum group metals, Figure 2. Pellet catalysts are being used by General Motors and American Motors; whereas Ford and Chrysler are using monolithic catalysts. The table below compares the PGM content and value of the catalysts.

Jan 1, 1986

The extraction and recovery of gold from copper electrorefining slimes by leaching and solvent extraction using dibutyl carbitol (DBC) has been practiced for several decades. Yet, the deportment of some common elements in this process has not been reported. The focus of this paper is to report the behavior of copper, bismuth, silver and selenium during the processing of industrial solutions by batch and continuous extraction on the laboratory scale. It was found that DBC, while an excellent extractor of gold from a highly oxidative chloride leach solution, also loads significant quantities of Cu, Bi, and Se. Silver was not present in significant quantities in the leach solution nor did it load appreciably. The deportment of gold and impurities are reported for batch and continuous operations of a two-stage extraction process using distribution ratios and separation factors.

Jan 1, 2010

By Richard B. Jacob

The High Gradient Magnetic Separator (HGMS), also known as the High Gradient Magnetic Filter (HGMF), is an effective device utilized in magnetic separation. This method of separation is gaining popularity in the separation of sub-micron material containing feebly magnetics. The most common use of this type of separator is in the removal of iron stained particles to improve the brightness of kaolin clay. Potential areas for use of this magnet include: (1) desulfurization of coal (2) the clean-up of mill effluent (3) removal of fine particulate matter from municipal and industrial waste (4) desulfurization of oil

Jan 1, 1983

By M. R. Shahan, W. R. Reed

A laboratory apparatus (shield dust simulator) was designed and constructed to simulate the dust generated during the advance of longwall hydraulic roof supports, or shields. The objective of the study was to develop a tool that could be used to test the hypothesis that foam applied to a mine roof prior to a shield advance could be used to reduce the respirable dust generated during shield advances. This paper will outline the design parameters for the development of the system, as well as describe baseline testing of coal and limestone dust. Results show the average instantaneous respirable dust concentrations that occurred during simulated shield advance. Confidence intervals were calculated from the instantaneous respirable dust data to determine the repeatability of the data produced by the device. INTRODUCTION During longwall mining, miners can be exposed to respirable dust that is generated during the advance of hydraulic roof supports or shields. National Institute for Occupational Safety and Health (NIOSH) researchers have conducted numerous surveys of longwall mining operations, benchmarking the operating practices and dust control measures in use. It has been determined that the shields are responsible for 27% of the respirable dust that is generated on the longwall face [1]. The dust generated by the shield advances ranks second, next to the longwall shearer which is accountable for 43% of the respirable dust generated on the longwall face. The respirable dust generated during the advance of the shields can be a significant contributor to the respirable dust exposure of the mining personnel operating at the longwall face, especially since some of this dust is generated in the walkway. Control systems designed to reduce the dust levels generated during the shield advance have the potential to greatly reduce the respirable dust exposures of the personnel downwind of these activities. One control technology to decrease the dust generated by the shield advances would be to apply a layer of foam to the forward shield-roof interface prior to the shield advance [2]. The blanketed layer of foam would interact with the material located on the top of the shield during the advance, preventing a portion of that dust from becoming entrained in the mine air. This layer of foam would be applied using a foaming nozzle located on the longwall shearer body that would spray foam on the roof surface as the shearer passed. Substantial laboratory work has been completed to determine the feasibility of this type of foam application. NIOSH engineers have classified the various characteristics of foaming agents, using foam expansion ratio and drainage as important properties, as well as developed the mechanical systems required to apply the foam safely to the mine roof [2, 3]. The construction of an apparatus that could simulate the mechanical interaction between the dust-laden shield top and mine roof was necessary to adequately test the hypothesis that foam could be an appropriate control. A team of engineers designed and constructed a shield dust simulator system allowing for in-house testing prior to a full-scale field investigation.

Jan 1, 2019

By Wallace W. Key

Problems of marketing industrial minerals to chemical manufacturers are manifold. In addition to the difficulty of establishing demarcation lines between "crude" and "processed" industrial (nonmetallic) minerals, and "industrial mineral compounds" further uncertainty exists because some chemical manufacturers do not talk the same language as the industrial mineral producer. For example, paint technologists use "rutile" and "anatase" to describe highly refined chemical compounds. The earth scientists use these terms to describe naturally occurring minerals. Further, marketing research problems are intensified because of the overlapping data of the Standard Industrial Classifications (SIC) groups, and the inexactness of "Chemical Industry," "Chemical and Allied Products Industries," and "Chemical Process Industries," which are widely variable in meaning but are often used interchangeably. Bureau of Mines information Circular 8244, "Minerals for Chemical Manufacturing," was the out¬growth of an attempt to unravel some of the problems caused by overlap of statistical data compared with actual industry practices. Using this study as a base, specific industrial mineral applications of some important sub-industry groups were analyzed for the; California chemical industry. Differences between local and national practices were compared. Practices usually differed, depending on cost and availability of alternate minerals, climate, idiosyncrasies, local regulations, and other conditions. Bureau of Mines Information Circular 8260, "Mineral Fillers for the California Pesticides Industry," is the first such analysis of, a sub-industry group. Other such studies are underway. Obtaining national data is easy, but to be able to compile meaningful information which can be revealed on a regional and State basis generally is difficult and often impossible. This paper will briefly emphasize some of the industrial mineral problems encountered, and bring out the needs and benefits being derived through the continued cooperation of authoritative officials concerned with supply and consumption of industrial minerals in government and industry.

Jan 1, 1965

By J. A. Bowersmith

The environment in which the surface mining industry operates today is considerably different than that of a few years ago. Increased pressure from the public, government, labor and internal industry factors calling for the fulfillment of rapidly changing expectations is especially intense in the surface coal mining industry. Such things as requirements for increased production, the Mine Health and Safety Act, environmental concerns and land reclamation, shortages of qualified and enthusiastic employees and market cycles coupled with price competition are but some of the specific items that are requiring the surface mining industry to better utilize equipment, materials, and labor resources available, There is one technical tool available which will assist management to increase productivity, improve cost control and assist in planning, organizing and operating surface mines. Industrial Engineering is that tool. Before a discussion of specific applications of Industrial Engineering to surface mining is conducted, it is worthwhile to review a definition of Industrial Engineering and the history of its development. The following definition has been adopted by the American Institute of Industrial Engineers: "Industrial Engineering is concerned with the design, improvement and installation of integrated systems of men, materials and equipment. It draws upon specialized know- ledge and skill in the mathematical, physical and social sciences, together with the principles and methods of engineering analysis and design, to specify, predict and evaluate the results to be obtained from such systems."

Jan 1, 1976

By Yi Luo

Subsurface strata movements and deformations caused by longwall mining operations in underground coal mines could affect many important coal mining activities, such as gob well degasification, ground water protection and multiple seam mining. The stratifications in the overburden have significant influence on the subsurface and surface movements and deformations in the ground subsidence process. An enhanced subsurface subsidence prediction model considering overburden stratifications has been introduced in this paper. In this method, the entire overburden strata are equally divided into a finite number of layers and the percent of the hard rocks in each layer is an additional input. The proven influence function method is applied to predict the subsidence on each of the predefined layers progressively upward using the predicted subsidence on the previous layer as the subsidence cause for the current layer. A computer program is developed to facilitate the calculations. A case demonstration is used to show the applicability of the proposed subsurface subsidence prediction model.

Jan 1, 2012

By Cary Hirner, Dan Lopez, Ross Webb, Stephen O’Connell

"Construction of the largest desalinization plant in the Americas has commenced in northern Chile. It is part of a several billion dollar expansion at a copper mine whose operations nearly stopped due to the challenge of securing a reliable source of water from the Pacific Ocean in a safe and environmentally sound manner. This paper discusses the risk management, design and construction of a quadruple chamber intake and outfall shaft, high capacity pump station, three 7m diameter vertically drilled marine shafts and three subsea tunnels constructed through challenging Andean hard-rock geology. The three 2.5m diameter subsea microtunnels are being mined with vertical curves through variable quality rock 30 meters beneath the ocean and retrieved in the wet from the 7m diameter marine shafts. INTRODUCTION AND BACKGROUND The battle for securing the rights to a constant water supply is a worldwide issue and nowhere is that more evident than the Atacama Desert of Chile, the world’s driest place with areas of the desert that have not seen rainfall in recorded history. The Atacama Desert also happens to be home to some of the world’s largest ore deposits which require huge amounts of water to extract and process. What available water there is comes from three main sources: deep seated wells, glacial water from the Andes Mountains, and desalinated water. Vying for water from wells and glacial streams and lakes are numerous agricultural and domestic facilities in the valleys surrounding the Atacama Desert. Environmental regulations and legal rulings have limited the amount of “natural” source water which can be used for mining purposes. Desalination plants are a known solution for combating water scarcity, albeit a costly one. The total estimated cost of constructing this desalination plant is over $3B USD, which will include a 2500lps capacity and an approximately 118km pipeline from the coast up to the mine located in the Andes. The overall scope of the project includes design, procurement, and construction packages for the 2500lps desalination plant including the seawater reverse osmosis plant, water conveyance to the mine, power transmission, the reservoir and the marine works package which forms the basis of this paper. Key components of the underground construction portion of the Marine Works are:"

Jan 1, 2016

By Russell L. Cook

Stringent environmental regulations, which have limited the use of sludge ponds, coupled with the economic incentive to clean more 'coal or to add fine coal cleaning additions to existing preparation plants have increased the use of static thickeners in preparation plants. The Lamella Gravity Settler, sometimes de signated Lamella Thickener, is a shallow depth sedimentation device which has been applied in a variety of industrial process and wastewater control projects in place of the conventional raked thickeners. This paper presents the theory and design of the La-mella Thickener, as well as describing the operating results from several full scale installations in a variety of Appalachian preparation plants.

Jan 1, 1977

By Jr. Smith

Silver-gold ratios were studied at the Tayoltita epithermal vein deposit using channel sample, channel sample line, stope, ore body and vein sample populations. The ratios are highly variable among individual channel samples (25:1 to greater than 500:1) with both high and low values randomly distributed within ore bodies and veins. Whole vein ratios for the fourteen most important ore producing structures range from 44:1 to 105:1, and show zonal distribution relative to two small granitic stocks, low values closest to the intrusives. The zoned nature of the deposit suggests that the stocks, apophyses of an underlying batholith of Late Eocene age, were the heat engines which powered the hydrothermal system responsible for ore deposition.

Jan 1, 1978

By Mark H. Johns

Leaching of waste material at Kennecott's Chino Mines Division at Santa Rita, New Mexico, has been accompanied by increasing difficulty in circulating leach solutions through the dumps. As a means of recognizing existing problems and considering alternative applications of the leaching concept, a leaching research program was proposed which could be applied to a specific, typical waste dump. Conclusions derived from the area could then be applied to other leaching areas at Chino. Associated with the program was an evaluation of the physical characteristics of the area using Chino's drilling and radiation logging techniques.

Jan 1, 1970

By Harlan N. Barton

A commercially available portable X-ray spectrograph, lightweight and of rugged construction for vehicle or field camp use, was used for the determination of Ba, Cu, Fe, Mn, Pb, Rb, Sr, and Zn in stream sediment geo- chemical samples. Investigations showed a relative standard deviation of 1-3 percent, detection limits of approximately 100 ppm; and significant matrix effects. Coefficients of correlation greater than 0.9 were obtained between portable X-ray and emission and atomic- absorption spectroscopy analyses. A geochemical map of a known mineralized area showed good agreement with maps prepared by other methods of analysis and sample media.

Jan 1, 1980

By Ronald H. Mullennex

The growing need for development of thinner, more erratic, or less easily- mined coals in the Appalachian region requires more detailed analysis of conditions and factors controlling or influencing deposition of these seams. The value of depositional modelling in evaluation of such coals has been demonstrated in many recent studies and publications. Such modelling may be applied to allow prediction of factors varying from regional coal occurrence trends to very local areas of seam discontinuities, but requires thorough utilization of all available types of data. Mapping of general depositional energies, as derived from basic geophysical and driller's logs, can be applied to specific prediction of coal occurrence, and projection of particular facies as representative of unique depositional features or conditions often proves more applicable to coal character delineation than does mapping of the coal itself. Depositional modelling and trend projection may also serve as a guideline in reserve classification and confidence-levels in reserve estimations.

Jan 1, 1981

By R. H. Lambeth

Disposal of mine tailings in "waters of the United States" is presently prohibited even though case studies indicate that the practice may be environmentally viable. To simulate disposal in the natural environment, nine containers of tailings and sediment were instrumented and placed on the ocean floor near Juneau, AK as were ninety-six biosample containers. Pore water concentrations of five metals were determined, and biota populations were characterized for both materials. After 500 days of exposure there were no statistical macro scale differences between tailings and sediment biota populations or Cu, Pb, and Zn pore water concentrations. Tailings released slightly more Fe than sediment, but sediment released significantly more Mn than tailings. Disposal of mine tailings in marine waters may be environmentally safe.

Jan 1, 1998

By Roy A. Grancher

CYCLING WITH CEMENT "THE WHEEL IS COME FULL CIRCLE" Shakespeare's King Lear Act V, Scene 3, Line 176 The time clock of the cement industry has been turned back to the early 1950s. After the trials and tribulations of the decade of the Sixties, the hands now stand where they did just over twenty years ago. Cement shipments have steadily increased, with a record 419 million barrel level (78.8 million tons) being reached last year. Plants are operating at average utilization rates in excess of 85 percent of rated capacity. The spread between supply and demand has narrowed to where a definite shortage of cement now exists within the industry. The notable and unfortunate difference between the two periods however is that, back then, cement's returns were a respectable 14 to 18 percent, whereas today they stand at less than half those levels. Insufficient return forms the present foundation of the U.S. cement industry. This lack is destined to have a cumulative effect. Just as the industry's balance between supply and demand is returning to favorable proportions, promising a period that has historically and now should generate those profit levels required to modernize and provide for capacity addition, cement instead finds itself frozen by federal price controls into the semi-depressed condition that has existed for over a decade and from which it was just starting to emerge. Capital is not attracted to continued low returns, and increasingly restrictive pollution control measures are necessitating great non-productive expenditures be made as definite costs to stay in business. Even a clouded crystal ball would reveal that additional cement plant closings can be expected.

Jan 1, 1972

By C. W. Armbrust

At FHC Gold Company's Paradise Peak Mine gold and silver are produced. Precious metals recovery rates are very satisfactory along with the recovery and production of a relative high volume of mercury. At Paradise Peak precious metals are recovered via the Merrill-Crowe process and delivered to the refinery area as a mercury-bearing precipitate cake. The recovery of mercury is then obtained through a vacuum retort system. The balance of the material is mixed with fluxes and then melted and cast into dore' bars for shipping. Issues of retort capacity and concerns over efficiency led to research into the retort process itself.

Jan 1, 1990