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By Ray E. Harris

All of the major raw materials (silica, soda ash, limestone, and feldspar) needed to manufacture most grades of glass are found in Wyoming. Additional advantages for the manufacture of glass include the state's geographic location, a well-developed transportation network, a favorable tax structure (no corporate or personal-income tax), and low energy costs. Inadequate local markets and prohibitive transportation costs to other markets have been the major obstacles to developing a glass industry in Wyoming, the least- populated state in the nation. The Rocky Mountain region only recently became a major market for glass, especially for the Colorado Front Range and Utah's Wasatch Front. Currently, changing costs of the production of glass, an increased market for con- tainer glass in the Colorado Front Range, and innovative production and transportation ideas (e.g., production of selected types of glass and bulk shipments of specification-glass pellets) favor developing a glass plant in Wyoming. Thus, the Wyoming State Geological Survey (WSGS) and other state agencies have been conducting studies and contacting investors in an effort to attract a glass-manufacturing plant to the state. Between 1987 and 1993, three locations of silica-sand and -rock deposits were studied in Wyoming (Cassa, Plumbago Creek, and John Blue). Funding was provided by the WSGS operating budget and local and state Department of Commerce economic- development grants. The reports on these areas were released between 1988 and 1993. In 1988-89, a California-based company conducted additional drilling and feasibility studies and prepared to construct a glass plant in Cheyenne, using the Cassa silica source. However, due to losses incurred by some of their other investments, the company did not proceed. In 1997, the Wyoming Science, Technology, and Energy Administration (STEA) contracted a market study for glass manufactured in Wyoming, using information provided by the WSGS. The STEA contacted several major glass producers, and a major glass-producing company began feasibility studies in January 1998, for the construction of a glass plant. In June 1998, bids to supply brown beer bottles to the Budweiser brewery northeast of Fort Collins, Colorado, were submitted by at least two companies that were considering glass-plant sites in Wyoming.

Jan 1, 1999

By G. Kraemer, J. A. Le Gac, P. R. ZETTWOOG

I. INTRODUCTION During the course of our activities in assisting mining companies, we have had access to the monitoring results for personnel from a large number of uranium mines. The results differ greatly from one mine to another. One of our objectives has been to discover the origin of these differences. It is evident that they are largely due to variations in the geological context, to mining methods, and to the organization of the work ; but we also found that the rigor with which measures are implemented to prevent the personnel from being exposed to radiations is also a cause. In order to advise mining operators effectively, we have asked ourselves the following question Given the dosimetric results of a mining site, how can it be known - if occupational exposure has been reduced to the lowest possible level (dose optimization principle recommended by the ICRP) ; - if the exposures were justified, which would not necessarily be the case following a questionable choice of the mining method, for instance, or a lack of efficiency in the maintenance and repairs of ventilation apparatus or even an excess of radiation protection. It is necessary to establish some criteria, while taking into consideration the specific conditions for each mine, in order to determine whether a mining company is adequately implementing radiation protection procedures. This need led us to attempt a modelization of the occupational exposures of uranium miners ; the preliminary phase is presented here. Although voluntarily still very basic, this model makes it possible to demonstrate the role of certain dynamic or passive variables. Moreover, the model presents the concept of specific irradiation of a mining site equal to the collective dose received per ton of uranium metal supplied to the uranium mill. The specific irradiation can therefore be used to indicate the effectiveness of radiation protection procedures at a given mining site. This model can be used for - previsional exposure studies based on the use of data gathered at each site, making it possible to compare various work methods and to determine prevention means ; - qualification of "radiation protection" procedures at a mining site ; - detection of unjustified exposures ; - research of ways to reduce inevitable exposures. 2. DETRIMENT TO BE ASSOCIATED WITH A GIVEN EXPOSURE DISTRIBUTION Respecting exposure limits ensures that delayed stochastic effects are the only health risks to workers. If the hypothesis of linearity in the dose-effect relationship is applied, the detriment to a group of workers is proportional to the sum of exposure for all the workers, or the collective exposure usually expressed as man x rem. On this point the linearity of effects hypothesis makes it possible to consider that two different standard deviation distributions having the same mean value are equivalent. It would be possible, then, to reduce the standard deviation by changing the distribution of workers at the various working places without changing the mean exposure value. In other words, without taking into consideration the practical implications, individual limits can be respected by rotating the personnel or by reducing the individual working period which would be compensated by increasing the number of workers. The collective dose would remain the same, which would justify the use of the concept of collective exposure. 3. "RADIATION PROTECTION" QUALITY INDEX AT VARIOUS MINING SITES Each mining site is responsible for its own collective dose, but it is also responsible for producing a certain amount of uranium metal in the ore sent to the uranium mill. These two quantities must be brought together in order to establish the "radiation protection" quality index of a mining site. This quality index, called-specific irradiation (Ir) is expressed in rem.ton -1 for external irradiation, in mJoule.ton-1 for inhaled [a]-energy, and in Ci.ton -1 for inhaled radon *. The specific irradiation represents the health hazard which must be associated to the extraction of one ton of uranium metal. Figures la and lb present a system of coordinates for which the axis of the abscisses is graduated in tons of U metal and the axis of the ordinates is graduated in units of collective exposures. In the EEC, the regulation is based on the measurement of the amounts of radon 222 inhaled.

Jan 1, 1981

By S. A. Saki, J. F. Brune

"INTRODUCTION Longwall coal mining leaves large areas where the coal has been made removed and the roof rock strata collapse, forming a zone of broken rock rubble called the gob. Figure 1 shows a typical longwall gob area along with the gate roads. The ventilation pattern for progressively sealed longwall panels follows a simple “U” pattern where fresh air is coursed inby to the headgate, flows along the face and exhausts through the outby tailgate as shown in figure 1(a). An important variation of this pattern is the back return (BR) arrangement where the exhaust air from the face is drawn inby and around the nearest open cross cut before it turns in the outby direction towards the exhaust fan. Figure 1(b) illustrates the use of back return. This arrangement moves the point of low pressure from the tailgate corner up to 60 m inby and thus maintains fresh air in the tailgate region that could otherwise be contaminated with gob air.The gob area may contain remnants of unmined coal or parts of overlying coal beds that continue to release methane, eventually filling the gob area with methane in concentrations far above the explosive range of about 4.5 to 15%. Many gob areas must be equipped with gob ventilation boreholes (GVBs) to extract methane, and GVBs often exhaust methane at concentrations from 50% to 90% (Saki, 2016). Due to oxidation processes occurring in the gob, the oxygen content is reduced to a low level, with nitrogen and CO2 making up the major remaining components of the gob atmosphere. FORMATION OF EXPLOSIVE GAS ZONES IN GOBS Since the longwall face area is ventilated with fresh air below 1% methane and the face and gob areas are not separated, an explosive fringe will form where the methane content lies within the explosive range and oxygen content remains above 12%. Figure 2 shows a typical development of such an EGZ. This figure is based on a computational fluid dynamics (CFD) model developed by CSM researchers to analyze gas concentrations and flow patterns in longwall mining. Figure 2(a) shows the formation of EGZ in the gob with a U type ventilation scheme, where EGZ lies right behind the shields in the tailgate corner. Figure 2(b) shows the formation of EGZ in the gob combining U type ventilation scheme with BR, where EGZ is pushed away from the face deep into the gob. The CFD modeling parameters and boundary conditions have been verified with field data from two cooperating, active longwall mines (see Worrall 2012, Marts 2015, Gilmore 2015 and Saki 2016). Other mine geometries, methane inflow rates and gob permeability distributions can be modeled to establish representative gob atmospheric conditions. Two GVBs were operating in the model, extracting 0.165 m3/sec each. The methane in the working areas and returns was kept below 1%. Methane flowing into the model from a rider coal bed above the mined seam was at the rate of 0.55 m3/sec."

Jan 1, 2017

By William Paul Robinson

I would like to first summarize the relevant health information relating to the workers and general populations around uranium mining as a basis for understanding the hazards associated with these operations and their available remedies. This discussion will summarize the literature on Radon and its daughters, among the most toxic uranium decay products. Second, I will discuss waste handling in the uranium industry: past, present and future, discussing exploration, mining, and milling and the volumes of water and solid and gaseous wastes which are associated with these various phases of uranium operations. This paper will also include a discussion of the various past and present materials handling technologies and their responsiveness to the concern for uranium waste isolation. I will then conclude with a summary of recent modifications in the relevant standards as applied to uranium mining and milling. Joseph Wagoner, a research epidemiologist with the U.S. Public Health Service has summarized the literature on uranium mining and its health effects in his written testimony as a commissioned witness in British Columbia Royal Commission of Inquiry into Uranium Mining in January of 1980, entitled Uranium, The U.S. Experience: A Lesson in History.1 Briefly summarizinq his report, as early as 1546, miners of uranium bearing ores in Central Europe were reported to have unusually hiqh frequencies of fatal lung disease2. As early as 1879, the real nature of pulmonary disorders among these miners was first diagnosed to be malignant neoplasia or lung cancers. Of 655 miners dying between 1875 and 1912, 40% or 276 of these Central Europe miners died of lung cancer.4 By 1939, it was reported that lung cancer mortality rate for miners in these Central European mining districts was several times (9.7 per 1000) higher than that for similar populations in Vienna, Austria (0.34 per 1000). Thus, before uranium mining began in the U.S., there was a considerable body of information linking uranium mining to lung cancers. The U.S. experience can be summarized in Table 1 also from Wagoner's B.C. Testimony.1 This table shows that through 1978, 205 respiratory cancer deaths have been observed among white underground uranium miners in the

Jan 1, 1980

By William Gleason

"Mining roots run deep in Glenrock, WY, a town that was founded in part, because of the coal mining that began in the late 1800s. But that rich history also now threatens large parts of the town that were built over the top of the mines. Like many towns in the Western United States, mining is a proud part of the historical fabric and heritage of the town, but the legacy issues from past mining activities continue to present challenges to modern-day engineers.In the case of Glenrock, a small town about 40 km (25 miles) east of Casper, it is flooding from a century of water that has accumulated in the down geologic dip of the furthest northeastern extent of 87 ha (217 acres) of mine workings that has made the town susceptible to sinkholes and other issues (Fig. 1).Full commercial coal mining production began in Glenrock in 1887 during the development of the Fremont, Elkhorn and Missouri Valley railway. Due to poor overlying roof rock and continuous flooding within Glenrock, Mines No. 1 and 2 were fully closed in 1909. During its history, an estimated 87 ha (217 acres) were mined with 50 to 60 percent extraction ratio within the eastern town limits through room-and-pillar mining. It is estimated that the mines produced 22 kt/a (25,000 stpy) during their lifetime. A century later, the water pressure built up in the northeastern most portion of the mine has created serious concerns for residents.In 2016, the Wyoming Department of Environmental Quality’s Abandoned Mine Lands Divisions (AML) investigated a number of subsidence events in the town including sinkholes following heavy precipitation. The AML investigations confirmed that most events were related to the previous mining in the area.Mitigation efforts on the mines were done in the 1980s and 1990s, but the problems in the town and in a nearby subdivision persisted, leading the AML to search for alternative solutions."

Nov 1, 2019

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 H. F. King

In 1982, the result of a 3-year study was published as "A Guide to the Understanding of Ore Reserve Estimation". The principal conclusions were that computation formed only part, and perhaps not the most important part, of an estimate and that the estimate should recognize that geological, mining engineering and metallurgical judgements formed an essential part of the eventual result. Subsequent expectation/realization studies of several mines have produced case histories which form the principal basis of the paper. These imply that geology is even a larger factor than thought earlier.

Jan 1, 1985

By M. S. Duffy

To exploit the mineral resources of fine grained ore bodies the minerals processing industry is turning to fine grinding technology, of which tower milling has become an established part. However, compared to other mills relatively little is known about the operating mechanisms in tower mills. In all milling processes one of the keys to understanding how they work is in knowing how their grinding media move. To investigate the ball motion in tower mills a glass unit was therefore constructed and measurements taken of the movement of the grinding media. This paper describes the results from this study.

Jan 1, 1998

By H. Fayed

Two-phase (water and air) flow in a self-aspirated WEMCO flotation machine has been investigated using computational fluid dynamics (CFD). The geometric model is a replica of a 300 m3 cell. A 72-degree sector containing two blades of the ten-blade rotor has been modeled and periodic boundary conditions are applied in the circumferential direction. Simulation of a sector of the machine allows acceptable resolution of the mean flow field using 4x106 grid points. The flow is modeled by Euler-Euler approach, and transport equations are solved using a commercial software ANSYS-CFX5 [1]. Unsteady simulations have been performed. In a self-aspirated machine, airflow rate is not known a prior; it is an output from the CFD simulation. Uniform mean bubble diameter of 0.7 mm has been specified as an input for the simulation. Air flow rate and power consumption have been monitored with time, and results indicate a stable operation. Air volume fraction contours and velocity field in different regions of the machine are presented and discussed.

Feb 27, 2013

By Ronney Rodrigues Silva, Renata Mendonca, Gabi Knesel, Cathrine Monyake

Locus Mining is working side-by-side with a prestigious iron ore company to evaluate the addition of Locus ESG-friendly green flotation reagents with the primary goal of improving recovery and grade. In this paper, we will focus on the cationic reverse flotation application. The most “established industry” reagents for cationic reverse flotation are amine as the collector, starch as the depressant, and in some cases frothers are also used (among them MIBC, pine oil, others). Here, we evaluate the synergies of different classes of eco-friendly biosurfactants and industry-standard reagents during the cationic reverse flotation method. Exploratory research was done first with an analog sample under different pHs, eight different biosurfactants with starch and no-starch, and a customized DOE was used to perform 145 microflotation tests. The results show Separation Efficiency from 20% (baseline) to 50% (biosurfactant), and Selectivity from 3.27 (baseline) to 5.67 (biosurfactant). Optimized result conditions were then applied to the iron ore samples received from our client to perform flotation tests on a Denver Lab cell. Similar results were obtained by improving Separation Efficiency and Selectivity, which corroborate with the previous work.

Feb 1, 2025

By L. Alagha, L. Sanchez-Calderon, M. Silwamba, W. Kirk

Selenium-rich metallurgical waste, also known commercially as “crude selenium,” is a byproduct of the copper (Cu) refining process. This by-product, contains ~ 90% selenium (Se), precious metals, platinum group metals (PGMs), and other critical elements. This study investigated the leaching efficiency of Se from the sludge under alkaline conditions using different oxidizing agents to enrich PGMs and precious metals in the leach solid residue. The effectiveness of each oxidizing agent during leaching was assessed and compared. Additionally, Eh-pH diagram for Se was established under specific experimental conditions and utilized to inform process optimization. Key variables, including leaching time, temperature, and oxidant concentration, were evaluated for their impact on the efficiency and the selectivity of the oxidative alkaline leaching process.

Feb 1, 2025

By Fiona Woody

Lime and calcium products are essential building blocks to the modern world, used to purify drinking water, preserve foods, control pollution, improve crop yields, stabilize soil, pave roads and support the production of steel, cement, glass and many other industrial processes. While lime is essential to society, it also has a sizable carbon footprint. Approximately 30 percent of the scope 1 greenhouse-gas emissions generated during lime production are related to fuel combustion, while the remaining 70 percent are created by the unavoidable chemical reactions during calcination.

Feb 1, 2026

By RENE GOMEZ, RAUL CASTRO

Estimation tools and models are now available to estimate fragmentation, but some variables have yet to be studied to understand their effect on the fragmentation process. One such variable whose mechanisms have yet to be studied is the residence time, which in block caving directly depends on the distance that fragments travel from their original position in the broken ore to the drawpoint. In this study, granular material fragmentation was characterized during its flow to understand its characteristics and mechanisms. The results show that the breakage of fragment singularities occurred mainly within medium and smaller sizes, increasing fine material during flow. Thus, the main fragmentation mechanism in experiments was identified as abrasion between rock fragments where fine material continuously increases as distance increases in spite of the high rock strength and the piston flow movement used. The results presented here can be applied to incorporate fragmentation during flow of large travel distance of ore such as in block caving.

By J. A. Marts, R. C. Gilmore, Jr. Bogin, S. Saki, J. F. Brune, J. W. Grubb

"Researchers at the Colorado School of Mines have studied the influence of headgate side ventilation controls near the longwall start-up room on the formation of explosive gas zones (EGZs) in underground coal longwall bleeder ventilated gobs. In a project funded by the National Institute for Occupational Safety and Health (NIOSH) researchers developed a Computational Fluid Dynamics (CFD) model to study the formation of methane-air mixtures in the gob, start-up room, and bleeder entries. The relative change in size and location of EGZs are examined in response to ventilation controls in the headgate side bleeder entries near the start-up room. Modeling suggests that adjustments to the ventilation controls can be made to minimize the size of the EGZ. However the EGZ may form in or around active working areas regardless of the ventilation control settings. Research found regulators on the crosscuts into start-up room and first entry inby can force air into to crosscuts outby the start-up room causing more air to flow through the gob. INTRODUCTION Underground longwall mine ventilation systems may operate with either a bleeder ventilated gob or a progressively sealed gob. Bleeder ventilated gobs must meet the standards for safe operation of the bleeder system by examining bleeder system effectiveness. As defined in the United States Mine Safety and Health Administration (MSHA) Program Policy Letter (PPL) No. P13-V-12 (MSHA 2013), the pillared area or gob is “any area where a reduction in pillar size has occurred during retreat mining” and includes the “caved and broken material, the interstices within the caved material, and the open spaces surrounding the caved material.” The PPL further states that the intended purpose of ventilating the gob is “to protect active workings from the hazards of methane accumulations …” The requirements for operating a bleeder system as stated in The United States Code of Federal Regulations (CFR 2013) Title 30 §75.334(b) is to pass ventilation air though the gob “and to continuously dilute and move methane-air mixtures [from the gob] away from active workings and into a return air course …” where the concentration cannot exceed 2 percent methane (CFR 30 § 75.323). Further clarification of the bleeder system as described in the PPL states the following: “A bleeder system includes the area from which pillars are wholly or partially recovered, bleeder entries, bleeder connectors, and all associated ventilation control devices that control the air movement through the area. Bleeder entries are air courses designed and maintained as part of the bleeder system.”"

Jan 1, 2015

By Georgene Renner, William R. Yernberg, Steve Kral

Advanced Terra Testing (ATT)is a full-service geotechnical testing laboratory. It specializes in rock and soil mechanics and geosynthetic materials testing. ATT provides services to the global mining industry. The company has performed more than 1,000 projects for more than 300 commercial and government clients. Services include coal pillar design testing, leach pad material and performance testing, tailings pile consolidation testing and closure and remediation services. Rock and soil mechanics tests include unconfined and triaxial strength, shear and tensile strength, permeability, index testing, consolidation, liquifaction potential, elastic moduli determinations, heap height versus percolation rate, long-term batch testing and dynamic loading tests.

Jan 1, 2003

By Cherie M. Tilley

The Stillwater Mining Co. of Nye, MT, is operating a platinum-palladium mine that requires an extensive system of footwall laterals to facilitate mine production. The 10-year mine plan calls for more than 48,300 lineal m (160,000 lineal ft) of footwall lateral. A rapid tunneling and raising system is necessary to sustain mine production schedules and achieve production goals. This article describes the results of using a Robbins 4.1-m-diam (l3.5ft-diam) tunnel boring machine (TBM) to develop the footwall laterals and a Robbins RBM-6SP raise boring machine to develop raises at the mine. The Stillwater Mining Co is a partnership between Chevron Resources Co. and Manville Corp. Chevron Resources is the managing partner. When the mine began production in September 1986, the owners were primarily concerned with the actual production of platinum and palladium, the grade minable and the amount that could be mined. As mine development and mine production proved feasible, the owners considered higher production levels. The Stillwater Mine is developed by a system of adits (known as footwall laterals) that are driven parallel to the ore bearing zone. This led mine officials to consider using a mechanical boring machine in the primary mine development. Previously, tunnel boring machines have not been used successfully in mining applications. Therefore, the owners decided to purchase a used machine to reduce the potential risk.

Jan 1, 1991

By Khosrow Badiozamani

Operating mines in Wyoming and Montana, which are generally characterized by shallow overburden and thick coal seams, are faced with reclamation problems which are unique to this area. Unlike the eastern or midwestern mines, removal of thick coal seams and lack of sufficient overburden creates overburden deficiencies that require careful evaluation prior to mining to insure compliance with regulatory requirements. Computer models and computer graphics can assist in such evaluation where appropriate alternatives can be selected which satisfies both the regulatory requirements and minimizes cost. This paper presents one such model used in evaluation of backfill requirements for restoration of surface and ground water regimes, restoration of mined-out areas to the approximate original contour, and the blending of the mined-out areas to the surrounding topography.

Jan 1, 1981

By Błażej Doroszuk, Robert Król

Mill drums are essential equipment in various industries for the comminution of materials. To optimize their design and operation for efficient and cost-effective processing, it is necessary to understand the behavior of the mill drum under various operating conditions. This study investigates the behavior of a mill drum using a combination of experimental and numerical methods. The factors that can influence the behavior of the mill drum, such as the size and shape of the mill, grinding media, rotational speed, filling level, and material properties, are discussed. Experimental methods can be limited in obtaining measurements of internal processes, so numerical methods such as the Discrete Element Method (DEM) are also used to simulate the behavior of the mill drum. In this study, the experimental measurements of the motion of the grinding media are obtained using computer vision methods, and the numerical simulations are calibrated using the experimental results. A designed experiment approach is used to evaluate the performance of the mill drum under various operating conditions. The results of this study can be useful for the design and optimization of mill drums to achieve better performance and energy efficiency.

Jun 25, 2023

By R. J. Sweigard

Three case studies were undertaken to investigate the role of land use potential evaluation in reclamation planning and to determine the impact of regional differences on the evaluation process. The three surface mines studied were representative of operations in the Appalachian, Interior, and Northern Great Plains provinces. The scope of the investigations included a survey of regional characteristics, a detailed investigation of the mining operations and site conditions, and an assessment of local land use planning activities in the area of the mine. Special attention was given to key factors that presently determine the use of reclaimed land. Also, for each case study, the postmining land use potential was evaluated using site planning principles. Specifically, the environmental, economic, and social impacts of several potential postmining land use plans were considered.

Jan 1, 1983

An insufficient hydrologic data base exists for most large and small coal basins in Alaska owing to the lack of need in the past to collect data. The runoff process is insufficiently understood which is complicated by specifically northern phenomenon, and the lack of understanding of hydrologic relationships in permafrost environment. This paper presents an understanding of the hydrologic effects of frozen ground and presents methods by which the influence of surface mining upon the hydrologic balance can be analyzed.

Jan 1, 1988