Search Documents

By Pengfei Wang, Guorui Feng, Shufeng Zhang, Yuxia Guo, Tingye Qi, Dian Li

"Based on the geological conditions of the No. 10203 mining face of the Xinyang coal mine, a numerical model of the longwall backfilling face is built using the FLAC3D software to calculate the limit broken length of the key strata. Based on the deformation laws of the immediate roof, the backfilling parameters are determined. Furthermore, the movement laws of the overburden strata with different volume filling rates (0, 40, 60, 100, and 100%) and with different layout forms of the filling strip (under a volume filling rate of 60%) are analyzed. The results of the numerical modeling show that the stress of the two sides of the working face and the deformation of the overlying rock are gradually reduced with the increment of the volume filling ratio. In view of the deformation of the roof strata within the allowable range, a volume filling rate of 60% is selected to simulate and analyze the filling effect under different layout forms of the filling strip. The filling width, stress concentration area, and layout form of the filling strip are the key factors to control the movement of the overlying strata. In addition, the probability integral formula is used to calculate and predict the ground subsidence on the filling area, which confirmed that the backfilling mining method is fully applicable in the Xinyang coal mine. The results of this study provide a certain theoretical basis for the determination of the filling process in the field.INTRODUCTIONIn China and other coal producing countries, gob is managed using the caving, filling, supporting, and slowly sinking methods (Zhang, Zhou, and Zhang, 2009). With the continuing development of the concept of green coal mining (Guo, Deng, and Zou, 2004), the filling method, which is safe and environmentally friendly, has been widely used in the field. On one hand, this method could reduce waste rock and other waste discharge. On the other hand, it could effectively slow the surface subsidence. Recently, strip-filling mining mostly adapted the arrangement of the strip backfill with equal intervals and widths (Xie et al., 2004), but the reasonability of this arrangement should be discussed. To arrange the intervals and width of the strip-filling body reasonably, Feng et al. (2019) put forward the “constructional backfill mining (CBM)” concept. The CBM is a type of backfill mining with low backfill rate, strong structural stability, and good backfill effect. The targets of the CBM include the efficient usage of solid waste resources in mining areas to reduce the backfill cost, the improvement of backfill materials and backfill technologies to increase the backfill efficiency, and rational planning of backfill and mining scheme to reuse the underground mining space. The determination of proper width and intervals for the strip-filling body is the main content of the CBM. Strip-filling mining using cemented coal gangue backfilling is the main method to undertake overburden of the overlying strata and to slow down the surface deformation. It also plays an effective role in cost reduction (Xu et al., 2007). This study focuses on proper determination of the strip-filling body parameters according to actual geological conditions by a simulation. It provides an appropriate reference for backfill mining in the Xinyang coal mine."

Jan 1, 2019

By E. D. Seymour

Minera Yanacocha operates a complex heap leach gold facility in the Northern Andes of Peru. Four leach pads and thirteen solution storage process ponds form an extremely complex system. Distinctly different wet season and dry season rainfall accumulations present unique challenges to the process water balance. Minera Yanacocha operates four excess water treatment facilities which discharge water to the environment at specific quality standards in order to maintain a balanced system. Numerous government agencies and non-government organizations are involved with the permitting, monitoring and control of the discharged water. Minera Yanacocha maintains a relationship with 65 villages and communities, with a population of approximately 29,000 people and the city of Cajamarca with approximately 100,000 residents. This paper provides a high level review of the system complexity, the water balance, the excess water treatment facilities and social aspects of solution management.

Jan 1, 2004

By Rolando Gonzalez

Mexico’s role in the world economic community continues to grow. And it is important that the country makes use of its natural wealth, including its large underground deposits of minerals and metals. With that in mind, Industrias Peñoles S.A. de C.V.(Peñoles), a mining, smelting and refining company, began mining lead, zinc and other metals from the Francisco I. Madero Project (FIM). The mine is located about 600 km (370 miles) northwest of Mexico City in the state of Zacatecas. Peñoles plans to remove about 3 Mt/a (3.3 million stpy) of ore from FIM. To achieve this goal, the company needs to optimize its processing, to maximize the amount of metal it extracts through FIM’s large flotation lead-zinc concentrator. To ensure high productivity, Peñoles and its contract engineering firm, M3 Engineering and Technology, of Tucson, AZ, have implemented anore processing system.

Jan 1, 2003

By M. D. Dennis

Precious metal mineralization at Mt. Hamilton" Nevada is associated with a poly-metallic, garnet-pyroxene skarn system developed in middle to upper Cambrian calcareous shales, limestones and dolomites. The skarn is developed around the Cretaceous Seligman and Monte cristo calc-alkaline stocks. Gold is associated with intense retrograde alteration. Later epithermal quartz veins containing gold, silver, base-metal sulfides, and sulfosalts cross-cut skarn alteration. Westmont Mining Inc. is currently developing two mineralized zones containing a geologic resource of approximately 7.7 M.T., which averages 0.05 OPT gold and 0.5 OPT silver. The project will have an estimated mine life of seven years, with a planned annual production rate of 35,000 ounces of gold and 300,000 ounces of silver.

Jan 1, 1989

By Stavros H. Constantopoulos

Mediterranean regions such as Greece, Turkey, Cyprus, Corsica and New Caledonia have experienced epidemics of malignant mesothelioma as a result of non-occupational, ??domestic?? exposure to tremolite asbestos and fibrous erionite. This exposure to tremolite asbestos and fibrous erionite is typified ??domestic?? due to its prevalence in regions with natural deposits of tremolite asbestos (or fibrous erionite) where the material from tremolite asbestos or fibrous erionite is used for domestic applications such as whitewashing. However, these exposures may be useful in examining the potential consequences of even small amounts of amphibole asbestos fibers in the ambient air. It can also elucidate the effects of fibers that behave like amphibole asbestos. However, this type of exposure is not useful for studying the potential effects of small amounts of asbestos in the ambient air of big cities due to the differing nature of the fiber types and modes of exposure between the regions. © 2008 Published by Elsevier Inc. Keywords: Tremolite asbestos; Erionite; Domestic; Environmental; Exposure

Jan 1, 2007

By William M. Schafer

Mining projects which contain sulfide mineralization face increasing regulatory hurdles due to environmental concerns over acid rock drainage (ARD) and the ability of long-term reclamation to protect water quality. Among regulatory agencies, much of the perception about sulfide projects has been based on conditions at historic mining sites at which little or no effort was made to control ARD. With proper design measures, ARD production can be greatly reduced or eliminated. The science of ARD prediction and control must be expanded to enable mine planners to anticipate the effect of various facility design options on ARD potential. Some common-sense examples of geochemical prediction techniques and mitigation measures for waste rock dumps, spent ore heaps, and mine pits are described.

Jan 1, 1992

By III Cocanour

The line scan video photometer is a personal computer (PC) based, software-driven instrument which is used for the real time, on-line analysis of industrial process streams. The novelty of the instrument lies in the integration of its various components: (l) a true Red/Green/Blue (R/G/B) color video camera; (2) a unique, line-scan color sample and hold technique which provides a 4 to 20 mA analog signal to a commercial 12 bit analog to digital (A/D) converter; (3) software which converts data through a color absorbance algorithm to correlate elemental color to concentration; and (4) software-based control which utilizes color data, along with temperature and conductivity data to control process equipment. The photometer can be used for noninvasive analysis wherever color hues are representative of process variables such as chemical concentrations or mineralogy color reflectance. The line scan video photometer has been successfully demonstrated in solvent extraction/electrowinning (SX/EW) and ball mill circuits of copper producers.

Jan 1, 1996

By Gordon Cook

American Electric Power Company (AEP operates 31 coal mines in three states, and some 26 electric generating stations (19 coal-fired) located in the Ohio River Basin. Normally the system burns over 36,071,600 tonnes (40,000,000 tons) of coal and generates in excess of 3.6 X 1018 J (100 billion kwh) of electricity per year. In 1975, AEP, in response to the progressively more stringent air quality requirements of the clean air act, acquired large low-sulfur reserves in Carbon County, Utah (Figure 1. Location Map). Price River Coal Company (PRCC) is the operator OF this multi-seam complex, which is part of the Book Cliffs coalfield at an elevation exceeding 1,829 m (6,000 ft.). The topography is mountainous and divided by numerous canyons. Flat areas are at a premium (Figure 2. Castle Gate Area). Modern high production longwall mining takes in some top and bottom waste, and in this particular operation, it amounts to about 14% of the ROM tonnage.

Jan 1, 1983

By Antonio De Biase

In October 2006, a 7m Double Shield TBM, boring through very poor volcanic formations, was pushed back by fluid mud, which presence had not been detected during previous field investigations, due to the high covers characterizing the majority of the tunnel axis. The present work describes the investigations made to gain better knowledge of the conditions in front and all around the TBM, the special measures implemented, the exploratory and bypass tunnels excavated, the extraordinary occurrences came true during the execution of these tunnels, the drainage campaigns, the design of the chamber excavated to free the TBM, the dismounting and restarting of the TBM.

By James W. Mitchell

On December 2, 1942, a scientific team lead by Nobel Prize winner Enrico Fermi first initiated and controlled a self-sustaining nuclear chain reaction. This historic event occurring beneath the stands of the University of Chicago football stadium instantly created an entirely new and tremendously broad area of technology. Indeed, the event probably changed the course of world history and considering the curret energy shortage, it probably came none too soon. Following many technological breakthroughs in the ensuing years, this event led to the first full scale nuclear fueled electric generating plant. In December, 1957, the Shippingport Nuclear Power Plant became operational and the United States had entered the era of the nuclear fueled electric generating station. Today, only fifteen years later, there are some thirty-five operating nuclear power plants in the United States with another 56 under construction and 116 on order. Still, we are only scratching the surface of this tremendous energy source. In 1970, less than one-percent of the total electric generating capacity in the United States was nuclear fueled. By 1985, it is projected that 45% of our generating capacity will result from nuclear power plants. These projections are based upoa statistics of six months to a year ago and considering the current energy shortage and recent attempts by the United States Atomic Energy Commission (USAEC) to speed the licensing process and encourage standardized plants, the contribution of nuclear power to our total generating capacity may be even greater. In summary, it is obvious that nuclear power is now, and will continue, playing an important role in our future. Those factions of government, industry and the professional community charged with fully developing this tremendous energy source must deal with it rationally, logically and expediently. The various environmental considerations in nuclear plant siting play an important role in the overall plan.

Jan 1, 1974

By W. D. Hausel

The Wyoming Province is an Archean craton which underlies portions of Idaho, Montana, Nevada, Utah, and much of Wyoming. The cratonic block consists of Archean age granite-gneiss with interspersed greenstone belts and related supracrustal terranes exposed in the cores of several Laramide uplifts. Resources found in the Province and in the adjacent accreted Proterozoic terrane include banded iron formation, Au, Pt, Pd, W, Sn, Cr, Ni, Zn, Cu, and diamonds. The Province shows many similarities to the mineral-rich cratons of the Canadian shield, the Rhodesian and Transvaal cratons of southern Africa, and the Pilbara and Yilgarn blocks of Western Australia, where much of the world's precious and strategic metal and gemstone resources are located.

Jan 1, 1991

By Haydn H. Murray

Although alumina constitutes about ii percent of the earth's crust, it is expensive to separate and purify for the production of aluminum with the exception off the alumina in bauxite. The United states has a variety of non-bauxite resources that could substitute for bauxite, including high alumina clays, alunite, dawsonite in oil shale, anorthosite, and nepheline syenite. Each of these resources are discussed from the standpoint of geology, geography, processing, potential recovery, and environmental problems. Potential by-products include silica from clays, potash and sulfuric acid from alunite, soda ash from dawsonite, and soda ash and potash from anorthosite and nepheline syenite.

Jan 1, 1982

By L. D. Patts, S. J. Janisko, E. G. Cauda, A. D. Bugarski, G. H. Schnakenberg, J. A. Hummer

Filtration systems with disposable filter elements (DFEs) are used in the underground coal mining industry to control particulate matter emissions from diesel-powered permissible and nonpermissible coal mining equipment. This study was conducted in underground mine conditions to evaluate three types of high-temperature DFEs used in those filtration systems. The DFEs were evaluated for their effects on the concentrations and size distributions of diesel aerosols and concentrations of nitric oxide (NO) and nitrogen dioxide (NO2). Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. After an initial DFE degreening period, the filtration system with all three DFEs was found to be very effective at reducing total mass concentrations of aerosols in the mine air. The effectiveness of DFEs in filtering aerosol mass was found to be a function of the engine operating conditions. The efficiency of the new DFEs significantly increased with operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on the performance of the DFE elements. The effectiveness of DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for DFEs when the engine was operated at high-load modes rather than at low-load modes. Initial heating of certain DFEs resulted in visible white smoke and substantially elevated aerosol number concentrations. The effects of the DFEs on the total concentration of nitrogen oxides (NOX) were found to be minor. The NO2 fraction was found to be generally lower for the DFEs than for the muffler. The engine-out NO2 fraction of the total NOX was found to be substantially higher for low-load modes than for high-load modes..

Jan 1, 2011

By C. M. Walck

The Rosebud district is located in the Kamma Mountains, southeast of the townsite of Sulphur, Nevada. Since discovery in 1989, LAC Minerals, in joint venture with Equinox Resources, has delineated a resource containing approximately 570,000 ounces of gold and 5,500,000 ounces of silver. The deposit is of the volcanic-hosted epithermal quartz-sericite type. Mineralization occurs in tabular zones in and along the hanging wall of the South Ridge fault, and in cross-cutting high-angle structures. Multiple stages of discontinuous stockwork gold-and silver-bearing quartz-calcite-clay veins cut variably clay-altered, silicified, and sericitized rhyolitic Miocene volcanic rocks.

Jan 1, 1993

By Tim O’Neil

The search for precious metals opened up the American West. And Nevada was right in the heart of this development. In the mid-19th century, prospectors seeking gold roamed the hills of Nevada and discovered the ComstockLode. The development of this huge silver and gold deposit began in1859 and was responsible for Nevada’s early entry to statehood. Mining was Nevada’s first industry. In more recent years, the Nevada mining industry has led the nation in gold, silver and barite production. Nevada also produces many other minerals. These include aggregates, clays, copper, diatomite, dolomite, gypsum, lime and limestone, lithium and magnesium compounds, perlite, salt and silica. Even today, Nevada’s mining industry continues to be a major economic force in the state. The mining industry has made more than $10 billion in capital investments in Nevada since 1985. And the value of Nevada’s mineral production last year was about $2.7 billion.

Jan 1, 2000

By Gökhan Çevikbilen, Ümit Karadoğan, Sevde Korkut, Berrak Teymur

This study proposes a methodology for dewatering of mine waste using a multistage process, combining geotextile tubes and anionic polyacrylamide (PAM), which accelerates the recycling process of water for aggregate mine waste facilities. For this purpose, waste from a rock quarry located in Istanbul was investigated. Flocculation tests revealed that the use of anionic PAM at an optimum dosage reduced sedimentation time and decreased turbidity. The compatibility of geotextiles and mine waste conditioned with different dosages of the effective PAM was evaluated by rapid dewatering tests, considering the water content of the filter cake, amount of infiltrated solid content, and rate of filtration. Geotextile dewatering tests were also performed on PAM-free and conditioned suspensions. The dewatering process was optimized by the use of a geotextile tube in two stages: (i) on the unconditioned suspension and (ii) on recovered PAM-conditioned leachate. Directing PAM-free non-hazardous soil-based material obtained in stage i to alternative beneficial uses is suggested, to minimize the volume of waste. Furthermore, recycling of the effluent obtained at the second stage of the proposed method will ensure more efficient water reuse

Sep 29, 2022

By J. Stawovy, A. Fourie, J. D. Quaranta

Coal refuse impoundments are disposal facilities specifically designed for the coal mining industry. Re-purposing refuse impoundments for co-disposal with natural gas flowback water and waste rock overburden has been investigated. The aims of this study were to investigate properties of coal refuse classification under the influence of co-disposed wastes as geochemical material exposure pathways from hydraulically exposed sodium and calcium ( Na+, Ca2+) cation loading from disposal of flowback water produced during the development of horizontal drilled natural shale gas frack wells, and waste rock having limestone characteristics. The geotechnical index classification of saturated cohesionless refuse is required to evaluate the liquefaction potential for strain or strength loss contributing to ground movements. This study is relevant to identifying changes in the coal refuse geotechnical index classification as sand-like, clay-like, or a borderline transitional material from the effects of ion and waste exposure in the impoundment’s reservoir porewater. Laboratory geotechnical tests were performed on fine coal refuse blended with different cations to classify the altered plastic behavior and index classification. Following determination of the index classification, the specimen’s stress–strain responses were investigated through isotropically consolidated undrained (ICU) triaxial compression tests. This experimental study culminated with two salient findings: the first is that introduction of ions alone into the refuse tailings or impoundment porewater resulted in significant material changes in property index classification, and the second finding was that the difference in refuse index classification did not correlate into noticeable effects of the monotonic undrained triaxial strength parameters.

Jul 5, 2022

By Hal McVey

"Philosophy" addresses the definition and assigning of importance to the marketing of by-products. Two examples, one in metals and the other in industrial minerals, explore prime product to by-product relationships. Relative revenues from all products illustrate the importance of by-products to economic feasibility. "Mechanics" takes a broad view of the types of marketing organizations that are applicable to individual circumstances in the marketplace. In-house marketing as well as agents, merchants and trading companies are outlined and discussed. Philosophy Definition Of Terms Philosophy Definition Of Terms The definition of terns for a paper such as this is generally a necessary but not-very-interesting exercise. However, in simply trying to clearly define the term "by-product" some interesting relationships between products arise and the line of demarcation between "product" and "by-product" often becomes obscure. The search for that distinction represents the philosophy portion of the title. A couple of definitions of philosophy can even help to set the tone for what follows. According to Webster, philosophy is : 1 Pursuit of wisdom. 2. A search for a general understanding of values and reality.

Jan 1, 1983

By W. C. Meyer

The concept of using powdered coal-in-oil-mixtures (COM) as a composite fuel to conserve oil resources and relieve import supply problems is being vigorously promoted by the Department of Energy via the sponsoring of various demonstration units (1). The idea of COM as a useful alternative fuel has been explored on and off for over 100 years (2). The approach must be capable of grinding, mixing, storing, and combusting COM with presumably only minor equipment changes on oil-fired boilers. DOE estimates that 56 000 m3 of oil (350 000 barrels) could be spared daily if a 50-50 COM was used to generate electricity. Of course, the ability of COM suppliers to prepare and deliver a stable suspension of COM at reasonable economic costs must be achieved if the concept is to be successful. This report reviews the various methods used to attain stable coal-oil mixtures. Various physical-chemical principles associated with each method of stabilization are also discussed.

Jan 1, 1981

By Robert D. Thomson

Land use is the single most important element affecting the quality of our physical environment. .The minerals industry is a user of land and by its very nature, directly affects the landscape. Mining is a very visible activity. Producers of sand and gravel, crushed stone, clay, cement and lime operate right at the interface of the public. These production sites must be located near population centers. People are more travel oriented than years ago and through use of the expanded interstate highway system visit remote and little-visited areas. They visit communities on their vacations, places they enjoy on weekends and places they drive past on business trips. Although not residents of these localities, they have a strong interest in changes that occur in the landscape. As a result, the public has a greater concern today about mining and its use of land. From 1930 through 1971, the minerals industry used 3.65 million acres, or 0.16 percent of the land mass in the United States (4)2/. Of the total 3.65 million acres utilized, about 59 percent was accounted for by the area of excavation, 20 percent by disposal of overburden and other mine wastes from surface mining, 13 percent by disposal of mill or processing wastes, and 5 percent by disposal of underground mine wastes; the remaining 3 percent was subsided or disturbed as a result of underground workings. Nonmetallic minerals and fossil fuels each accounted for 43 percent of surface land used during 1930-71; the metal mining industry utilized the remaining 14 percent.

Jan 1, 1976