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By K. Louk, E. Gilliland, N. Ripepi, M. Karmis

"Carbon dioxide (CO2) injection in deep unmineable coal seams can enhance coalbed methane (CBM) recovery as well as effectively and permanently store the CO2. Enhanced coalbed methane (ECBM) recovery and CO2 storage capacity can be improved by altering injection parameters including the injection well locations, number of injection wells, and the time and rate of the injection. A sensitivity study was performed with sixteen different injection scenarios on a coalbed methane field in Buchanan County, Virginia to understand the influence of the injection parameters on methane production, CO2 storage and the extent of the CO2 plume. History matching was done for the gas and water production period prior to injection based on field data from an active US Department of Energy funded pilot project. INTRODUCTION The coal structure is a combination of the coal matrix and cleats. In a CBM reservoir, the methane (CH4) is stored in the matrix under adsorption properties, not as a free gas. During CH4 production, the reservoir pressure is reduced and gas is released from the surface of the coal, diffuses through the matrix and transmits to fractures (man-made or natural) via the cleat network. Fractures and cleats are the major parameters that influence gas flow capacity because deliverability of the CH4 to the production well is controlled by the cleat permeability. As gas production continues over time, CH4 desorbs from coal, and coal matrix volume starts to decrease. This volume decrease in the matrix opens up the cleats, matrix shrinkage, which leads to a permeability increase. Several emprical (Harpalani and Schraufnagel 1990a, 1990b; Harpalani and Chen 1995, 1997; Harpalani and Mitra 2010; Pan et al. 2010; Liu et al. 2012; Mitra et al. 2012) and analytical (Palmer 2009; Liu and Harpalani 2013) studies have reported this relationship between pressure and permeability. Those studies showed that permeability is an important parameter in CH4 production performance. Furthermore, during gas production, water is produced through the cleat system as well, therefore gas-water relative permeability must be also considered in evaluating production performance (Gash et al., 1991). In the CO2 injection scenario the opposite occurs because CO2 has a higher adsorption affinity than CH4. CO2 replaces CH4 in the matrix of the coal and increases the volume of the coal matrix, matrix swelling, and results in a permeability decrease. Harpalani and Mitra (2010) concluded in their experimental study that swelling of the coal matrix due to the CO2 injection is two to three times more than the sorption of CH4, resulting in large permeability changes during CO2 injection."

Jan 1, 2016

By L. K. Holder

The White King / Lucky Lass Superfund site consists of two former uranium mines in south-central Oregon. The remedy included consolidating two large mining overburden stockpiles that contained low levels of radioactivity and heavy metals by moving over 700,000 cubic yards of material and then capping the combined stockpile. An innovative armored cap design was used to minimize the stockpile footprint and thereby prevent disturbing existing wetlands. In addition, the stockpile was designed to merge into the surrounding topography. The remedy also included stream restoration and development of new wetlands. The stream was returned to its pre-mining channel, with the addition of hydraulic features to create new wetlands. The wetlands have greatly enhanced the ecological value of the remedy and the site.

Feb 23, 2014

By S. Dubnewych, S. Kieffer, M. T. McRae, R. R. Redd

The seismic vulnerability of the existing outlet tower at Lake Mathews reservoir, located in Riverside County, California, necessitated the design of a new outlet facility to assure serviceability of the facility following a major earthquake. The components of the proposed facility include: a new outlet tower; a shaft; a new outlet tunnel; an approach channel that will be excavated underwater; and two short tunnels that will connect the new outlet tunnel to the existing outlet tunnel via the shaft. As the new facilities will be constructed while the reservoir is in operation, a cofferdam will be constructed around the site of the new outlet tower. The design for the underground facilities used a combination of empirical methods; limit equilibrium analyses, including displacement-based pseudo-static analyses for dynamic loading conditions; and numerical analyses. This paper outlines the design methodology used to develop an innovative design for the facilities which can be constructed within the time frame required by the operational schedule of the reservoir and existing outlet facility.

Jan 1, 1999

By William E. Bruce

Percussive drill calibration experiments performed by the Bureau of Mines on two drills are described. The use of a linear velocity transducer to determine piston velocity, blow frequency, and piston stroke length is discussed. Data are presented on the relationships between maximum work rate and feed air pressure. Penetration rates in nine rock types were measured for the same two drills. Physical properties of the nine rock types are presented in tabular and graphical form to show relationships between penetration rates and physical properties. Finally, conclusions are drawn as to the potential use of these data to predict percussive drilling rates.

Jan 1, 1970

By Y. Lv, H. Ye, D. Du

Electrolytic manganese residue (EMR) is a kind of industrial solid waste with high silicon content that contains harmful metal elements such as chromium (Cr), copper (Cu), lead (Pb), cadmium (Cd), nickel (Ni) and cobalt (Co). Developing a highly effective and environmentally friendly process to treat EMR is important, both for the reutilization of metal resources and for environmental sustainability. In this study, the bioleaching of available silicon from EMR using silicate bacteria is investigated, with flask experiments conducted to optimize the parameters in the bioleaching system. For metal ions, the concentrations of manganese (Mn), Co, Ni and Pb in solution were measured to determine the environmental safety effects before and after bioleaching. The results show that the bioleaching rates of available silicon in the slag were mainly affected by the temperature, pH and pulp density. Under the optimal conditions of temperature of 30 °C, pH of 7.0, pulp density of 5 percent, shake flask rotational speed of approximately 210 rpm, particle size of approximately 0.150 mm and leaching time of 16 d, the concentrations of available silicon in the bioleaching system rose to approximately 110 to 140 mg/L. The metals remaining in the residues were mainly bonded in stable fractions, with concentrations lower in the leachate after bioleaching. This study demonstrates that silicate bacteria can be used to increase the contents of available silicon from EMR, and that bioleaching technology can realize the harmless resource utilization of EMR.

By P. G. Dempsey, J. R. Heberger, J. P. Pollard

During a mine disaster or emergency, underground air can quickly become contaminated. In these circumstances, all underground mine workers are taught to don breathable air supply units at the first sign of an emergency. However, no contemporary oxygen consumption data is available for the purposes of designing breathing air supply equipment specifically for mine escape. Further, it would be useful to quantify the oxygen requirements of breathing air supply users for various escape scenarios. To address this need, 14 participants crawled a distance of 305 m each while their breath-by-breath oxygen consumption measurements were taken. Using these data, linear regression models were developed to determine peak and average oxygen consumption rates as well as total oxygen consumption. These models can be used by manufacturers of breathing air supply equipment to aid in the design of devices that would be capable of producing sufficient on-demand oxygen to allow miners to perform self-escape.

Jan 1, 2015

By J. Marsden

Lift height, overall heap height and climate all play an important role in determining precious metals leaching rates, recoveries, operating costs and capital cost requirements for heap leaching operations. The effects of these factors are not easy to predict from testwork, and this can result in unexpected delays in metal production, lower recoveries than expected and higher capital and operating costs than necessary. This paper investigates the economic impact of lift height, overall heap height and climate on heap leaching and provides criteria to assist in the design and operation of leaching facilities. Descriptions of three heap leach operations in the western USA are provided to support the discussions and conclusions.

Jan 1, 1995

By Steven Keim, Steven Stansfield, Kevin Andrews

Geotechnical, geological, and hydrogeological fieldwork and data collection for the mining industry is often conducted by younger, less-experienced staff members. In many cases, fieldwork personnel are recent college graduates or are otherwise relatively new to the mining industry. Due to busy schedules, staffing shortages, project budgets, and in some cases, poor management, new fieldwork hires often do not receive thorough training. In the past and the present, many workers in the mining industry learn(ed) by “doing.” While this is still considered to be the most practical approach and the easiest way for a company to determine the skill set of an employee, there is always some risk involved in the “feet to the fire” method. The reality is that field personnel are often collecting data on which major operational decisions will be made or on which regulators will base enforcement decisions. Inadequately trained or inexperienced field personnel may collect inaccurate data or fail to recognize key conditions that may influence decisions made by regulators, design engineers, mine managers, and corporate leaders. Even the best engineers may come to incorrect conclusions if they are starting with poor input data. Decisions based on inaccurate data often result in delays, budget issues, unsafe conditions, or even worse consequences. This paper provides numerous mining industry examples of incidences where inaccurately collected field information did, or could have, resulted in major adverse consequences. The paper also offers some simple approaches to minimizing the potential for such problems.

Jul 1, 2023

By Richard D. Begley

This paper will present the results of an analysis of several abandoned coal mine projects and includes field data for over a dozen different reclamation projects recently completed in the state of West . Virginia. The analysis was performed with the objective of summarizing and or classification of the environmental consequences with reference to the characteristics of the mining facilities (surface, underground, etc.). The analysis also addressed the itemized cost of remediation with respect to procedures, environmental concerns and time. The results of the analysis are that each abandoned coal mine site in West Virginia have/had many unique features and in most cases include a combination of environmental concerns that complicate comparisons. The study also revealed that the abandoned mine land program for mines abandoned prior to 1977 that is being financed by a tax on the production of coal, has produced many benefits for the state of West Virginia. This grant program administered by the Office of Surface Mining, has resulted in a high quality methodology of remediation that has been successful for many years in greatly minimizing and/or eliminating environmental concerns from abandoned coal mines.

Jan 1, 1997

By David B. Brooks

I gratefully acknowledge the help of a number of American and Canadian geologists, in both federal surveys and in private firms, who took the time to discuss this problem with me. Hans Landsberg and Bruce Netschert also followed the study with interest and encouragement. In their 1961 monograph, THE FUTURE SUPPLY OF THE MAJOR METALS, Bruce Netschert and Hans Landsberg noted that identified potential resources (that is, known but submarginal resources) of lead and zinc were much lower relative to reserves (that is, known and supermarginal resources) than was the same ratio for other metals.1/ Put another way, it seemed that for such metals as iron, manganese, copper, and aluminum, slightly more favorable economic conditions or modest advances in technology would greatly increase reserves by permitting the exploitation of vest quantities of leaner or deeper or otherwise less valuable mineral deposits. But for lead and zinc, Netschert and Landsberg concluded that either: "(1) there is relatively little material below present cutoff grades; [or] (2) such material exists, but for some reason there are no data.? 2/ This situation, which they called "the lead-zinc anomaly" has been subsequently discussed by other authors. The purpose of this paper is to carry the discussion further by examining the evidence in favor of (1) and (2) and by advancing a third alternative.

Jan 1, 1967

By Georges Verly

The estimation of local recoveries is an important issue in a selective mining operation. Two techniques, probability kriging and multigaussian kriging, are applied to estimate local recoveries at Jerritt Canyon. The pros and cons of each method are discussed in light of the results. Both methods provide simple and satisfactory solutions to the problem of estimating local recoveries. Consequently, they can be useful tools to work with in a selective mining operation.

Jan 1, 1984

By G. T. Lineberry

There is a critical need for effective instructional materials at the university level and for an upgrading of mine safety and health in the mining engineering curriculum. A fundamental approach to mine safety and health is recast into the familiar 3 E's: engineering, education, and enforcement, in that order. Each is briefly reviewed and their interdependence emphasized. A unique philosophy for successfully integrating safety and health principles into the mining engineering curriculum is offered. The concept of textbook ?tailoring? is discussed and defended, permitting rapid assemblage and synthesis of existing educational materials. Final recommendations are made for a u, comprehensive approach to mine safety and health education in the undergraduate curriculum.

Jan 1, 1987

By AMIT SHARMA, BIBHUTI BHUSAN MANDAL

This paper describes the vibration transmissibility characteristics of mining vehicle seats under dynamic conditions in an opencast iron ore mine. Magnitude and frequency contents of vibration signals on the seat floor as well as on top of the seats were measured to record the change during transmission. The conventional rigid seats were found to resonate at about 4 Hz, which coincides with the resonance of the human spine. The pneumatic suspension seats also proved to be more efficient in attenuating the overall vibration energy transmitted from the vehicle chassis to the human body.

By E. A. Sondreal

Requirements of flue gas desulfurization (FGD) for Eastern and Western U.S. coals will not be the same because of differences in coal sulfur content, ash analysis, and beating value. The effects of these differences and of limited availability of water in the West are the subjects of this paper. Eastern and Central bituminous coals are generally high in sulfur and require removal efficiencies in the range of 70 to 90 percent to meet the Federal emission standard of 1.2 lb SO2/MMBtu. Ash in Eastern coals is low in alkali content and is relatively insoluble in scrubber solutions. High sulfur content and market availability make salable product methods more attractive in the fast and Central United States than in the West. Western subbituminous coals and lignites are generally low in sulfur content, however, only a few deposits could reliably meet the Federal emission standard without FGD, Required removal efficiencies generally fall in the range of 0 to 60 percent to meet the 1.2 lb SO2/MMBtu limit. If the standard were raised to 2 lb S02/MMBtu, approximately two-thirds of Western coals could be burned without FGD. Some Western coals contain ash high in alkali, some of which is soluble in scrubber solutions. This complicates scrubber chemistry, but it also provides the meant for displacing some or all of the limestone requirements when only moderate S02 removal is required. Dry areas in the West would benefit from full commercial developement of dry processes of FGD.

Jan 1, 1974

By Abb Raymond

Finely processed industrial minerals in "powdered" form have long been utilized by the plastics, paint, rubber, paper, ceramics, and adhesives industries as fillers, extenders, coatings and special additives. These minerals, primarily calcium carbonate, talc, kaolin, titanium dioxide, and the like, have provided economic, uniform and consistent base materials which have, in turn, been used by the referenced industries to manufacture quality products. The focus of this paper will be the development of equipment and systems at ABB Raymond for the dry processing of such non-metallic minerals in order to meet what have become increasingly stringent requirements of the producers of these minerals. Changes in these requirements seem to have been accelerating rapidly during the last ten years, and it is expected this process will continue into the 1990's.

Jan 1, 1990

By J. Y. Lee, J. Kang

"A selective chlorination process using cuprous chloride (CuCl) was investigated for producing high-grade chalcocite (Cu2S) from chalcopyrite (CuFeS2) feed. The chalcopyrite feed was reacted with CuCl in the presence or absence of sulfur (S) at temperatures between 900 and 1,100 K for five hours under an argon gas atmosphere. The experimental results indicate that iron (Fe) was selectively removed from the chalcopyrite feed as ferrous chloride (FeCl2) at 1,100K and the mass percentage of Fe thus decreased from 31.5 percent in the feed to less than 0.05 percent in the residue, under certain conditions. As a result, high-grade Cu2S was obtained from chalcopyrite in a single step. This new selective chlorination of chalcopyrite using CuCl as a chlorinating agent is therefore feasible for producing high-grade Cu2S.IntroductionCurrently, blister copper (Cu) is commercially produced from sulfide ores by pyrometallurgical methods. These methods entail matte smelting and converting, with the removal of iron (Fe) and sulfur (S) as slag — mainly Fe2SiO4 — and sulfur dioxide (SO2) gas, respectively.In the pyrometallurgical method, as shown in Fig. 1 (Schlesinger et al., 2011), Fe is removed through two steps at high temperatures of around 1,500 K to reduce the loss of Cu during slag formation. However, the slag still contains 1 to 8 percent Cu. Therefore, Cu in the slag is recovered by slag treatment processes, after which the concentration of Cu in the slag decreases to around 0.4 to 1.3 percent. Although Cu is recovered, the slag that had undergone the treatment processes is difficult to use as a feedstock for ironmaking owing to the small amount of Cu remaining in the slag (Schlesinger et al., 2011).In addition, large amounts of SO2 gas are generated by the oxidation of S in the current Cu production process. The SO2 gas generated is captured and used to produce sulfuric acid (H2SO4). However, despite the development of SO2 gas-capture technologies, the emission of SO2 gas is still a problem in terms of environmental considerations.Several studies had been carried out in the past to overcome the drawbacks of the current process. The extraction of Cu from sulfide ores using a chlorination process is one alternative that had been investigated by several researchers. Most chlorination processes used chlorine gas (Cl2) as a chlorinating agent at temperatures between 573 and 1,023 K under an inert atmosphere (Donaldson and Kershner, 1962; Olsen et al., 1973; Kumar, Li and Warren, 1985, 1987; Kanari et al., 1999; Kanari, Gaballah and Allain, 2001)."

Jan 1, 2017

By Manuel Gomez

This, report presents correlative data on ash and sulfur forms for Pittsburgh seam coal from Greene County, Pa. Prediction equations were developed for sulfur form distributions and washability characteristics. The equations developed were evaluated with an independent set of exploration core samples. It was demonstrated-that both sulfur distributions and washability characteristic's can be predicted from exploration core data ahead of mining. This information can improve the efficiency of selective mining techniques for the production of a uniform metallurgical coal product.

Jan 1, 1967

By Jaeheon Lee, Junmo Ahn, Jae-Yeon Kim, Yoo-Jin Kim, Jiajia Wu, Eun-Woo Kim, Jai-Won Byeon, Jun-Jae Lee

The surge in demand for battery materials, coupled with environmental challenges linked to battery disposal, underscores the need to recycle spent lithium-ion batteries (LIBs). Green recycling approaches, in particular, have garnered attention for battery recycling. In this study, a hydrometallurgical method using a synergetic organic lixiviant combining methanesulfonic acid (MSA) and citric acid (CA) as an alternative to inorganic mineral acids was introduced as a green approach to recycle cathode materials of LIBs. The conditions for leaching and recovery processes were optimized. Cathode materials were regenerated using the recovered materials. Moreover, the leaching performance and economic feasibility of this leaching system were compared with those of various other organic acids.

Feb 1, 2024

By August E. Vandale

I speak to you today on the subject assigned to me, "Subsidence - a Real or Imaginary Problem", as a representative of Consolidation Coal Company (a wholly owned subsidiary of Continental Oil Company). The information I relate to you is our experience in the Pittsburgh Coal Company Division of Consol and covers the Pennsylvania properties and mines with particular emphasis on the mines in the south- western portion of the State or in the immediate vicinity of Pittsburgh, Pa. Mining of Freeport and Pittsburgh seams of coal in the Pittsburgh vicinity dates back over one hundred years. Consol, or its predecessor, Pittsburgh Coal Company, has been actively engaged in mining in the area since Pittsburgh Coal Company was organized in 1900. Pittsburgh, Pennsylvania came into prominence as the Steel City largely because of the vast reserves of high grade metallurgical coal readily available in the immediate vicinity and also because of its favorable river transportation. Early in the 1900's we operated over 100 small coal mines, with operations located in the Counties of Allegheny, Fayette, Washington, Westmoreland. We have also operated mines in Somerset and Greene Counties. Titles in Pennsylvania can be in three estates: (1) title in fee, (2) title to the mineral, (3) mining rights permitting the removal and extraction of the mineral with or without waiver of surface damage. Consol has over the years acquired good legal title to the coal lands purchased from individual farm owners, with good broad mining rights, and in 98% or more of its title has a complete waiver of surface damage or the right to subside the surface land. In the early days of our Company, individual coal farms were purchased from land owners. Many of these titles severed the coal estate from the in fee title and good mining rights with waiver of surface were conveyed in the original severance deed. Thus, minable coal reserves were put together by the purchase of the coal under many individual farms in an area. In the early years, the mines practiced hand dug mining - later going to mechanical cutting with hand loading of the coal. Systems used were entry driving with room and rib panels. We have practiced full recovery mining as far as practical during the years of hand loading, as well as in the later years when the mines were mechanized. Mining system layouts, methods and procedures have changed from time to time to keep pace with improved mining machinery and new inovations, such as roof bolting and rubber tired haulage.

Jan 1, 1967

By C. H. Grant

The Dew Chemical Company has been engaged in explosives research since 1953. The incentive for this research was based on the desire to find additional markets and uses for magnesium metal of which Dow is a heavy producer. The thermodynamic calculations for explosives incorporating light metals indicate energies approximately twice that of non-metallized explosives currently being used. Early in 1960, we acquired additional patent rights from independent inventors and decided to set up a development station at Virginia, Minnesota, to conduct a commercial testing and market evaluation program with this new product. The actual manufacturing of the explosive was to take place in the bore holes. Due to the complexities involved in controlling the manufacture of the explosive in the bore hole, performance was sometimes in doubt. Furthermore, our experience indicated that the metallized explosive systems could not be evaluated by the standard laboratory methods then being used, and it was necessary for us to look for more suitable research methods. Tests were conducted on several known methods for explosive evaluation. The most promising were the Navy underwater method for energy evaluation, and a modified Livingston crater method intended to compare explosive performance in rock. After shooting over two thousand charges of eight to 60 pounds under water and in taconites and granites with many types of explosives, we have developed a metallized explosive which is now being manufactured at a pilot plant in Virginia, Minnesota, and is being evaluated commercially.

Jan 1, 1963