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By E. Bane Kroeger

Plane failure in rock and soil slopes is usually caused by the intersection of a discontinuity plane with a slope face. Normally, these discontinuities are weaker than the surrounding intact rock and provide a surface along which movement can occur. The discontinuities are typically analyzed to determine the stability of a particular slope. One problem that arises when evaluating the stability of a planar feature is that the method for planar analysis is two-dimensional and has difficulty dealing with planes that are oblique to the slope face. Several researchers have stated in the past that planar failures are a special case of wedge failure. Wedge failures occur when two planar discontinuities intersect in an unfavorable manner. Sliding can occur along the intersection of the planes. Wedge failures are very common in rock slopes and can often be problematic. Wedge stability analysis methods are typically three-dimensional and can analyze planar features that are very oblique to the slope face. Wedge failure analysis can also be used to determine the stability of planar features with good success. One advantage to using wedge analysis over plane analysis is that a tension crack can be both non-vertical and oblique to the slope face in the wedge analysis. This allows the engineer to more closely match field conditions. It also negates the need for the engineer to have two separate software packages to analyze a single slope, saving both time and money.

Jan 1, 2002

By E. (Walt) van Walsum

The MPTM was first applied in the U.S.A. in 1950 as described by Lewis, W.E., 1951. The method was then abandoned in the USA and rediscovered some 20 years later in France where it was greatly improved and widened in its scope of application. It was subsequently successfully introduced to Italy and Spain. The technique, at its present stage of development, provides solutions to tunneling in soil and in the softer rock types, which often were troublesome geological environments for tunneling. When used in conjunction with drilling-and-blasting, over break, excessive vibration, noise and fissuring of the rock can all be avoided. When used as an alternative to the New Austrian Tunneling Method (NATM), the MPTM provides safe, full face tunneling in stead of multiple headings, excavated sequentially; in addition, surface settlement can be virtually eliminated. When used as an alternative to a TBM, the method's flexibility and low capital cost make it attractive. This attractiveness is enhanced when ground conditions are erratic or when the length of tunnel to be excavated is limited. The method holds promise for tunnels of large cross section, to be excavated in soft ground or rock with unconfined compressive strengths of less than 80 MPa (11 600 psi). While in itself not new, recognition and development of the method's potential are. Further development work, aimed at increasing the range over which the MPTM can be applied, is in progress.

Jan 1, 1993

By Leonid P. Ni, Askar M. Kunayev

It is well known that processing of the high-silicon bauxites for obtaining alumina by the hydrochemical Bayer process is irrational due to the significant losses of alumina and alkali with red mud. The main source of losses of the mentioned compounds under the conditions of leaching by the Bayer process is the formation of difficultly soluble sodium alumosilicate of the composition Na20 .Al203, 2Si02 . n H20. A conventional method of an extra recovery of alumina as well as of regeneration of alkali out of red mud is the high-temperature sintering of the latter with soda and limestone with the subsequent leaching of sodium aluminate from the sinter by water or soda solution. A sequential version of the Bayer-sintering flow chart recommended for the prosessing of bauxites with an increased content of silica is based on this method. However, the sintering method is not the only alkaline method allowing to make an extra recovery of alumina likewise of alkali from red mud. Our investigations showed/I/, that the components mentioned can be recovered by a pure hydrochemical method of treating red mud with concentrated alkaline solutions, with lime (Ca0) being present, that was earlier succesfully used in the development of the hydrochemical method of processing nepheline rocks/2/. The possibility of extracting alumina and alkali from red mud is based on the reactions which can be schematically represented in the following way:

Jan 1, 1984

By R. W. Mossman, George E. Heim

Seismic exploration techniques offer the engineer and geologist a way of obtaining detailed information on the physical parameters and geometry of the rocks where extensive underground excavation or tunneling is proposed. Use of the seismic method can provide a greater amount of detailed information at relatively less cost than can be obtained by any other known subsurface exploration method. Boreholes are still required for calibration of the seismic data but at a much wider geographic spacing than otherwise would be needed for subsurface mapping. The seismic data can define with precision the actual location of zones of flexure or fracture of the rocks and reveal the configuration of the surface of the rock layers. ENGINEERING PROBLEMS One of the major requirements in the planning of subsurface installations is that of locating tunnels and other underground openings in favorable rock units. Such rock units should exhibit uniformity of composition, both vertically and horizontally, to minimize variation in excavation techniques. The depth and thickness of the unit must be known: a 30-foot diameter tunnel cannot be contained in a 25-foot thick limestone. The rock unit needs to be as free as possible from structural defects and should be suited to efficient excavation procedures. If liquid conduits are planned, the slope of the rock unit needs to be known so that maximum advantage can be taken of gravity flow with the tunnels wholly contained within the unit.

Jan 1, 1997

By Ryota Kasahara

In 1981, a gas outburst accident occurred in the Yubari Shintanko coal mine, the only expectant mine in Japan, it caused 93 deaths. As a result, Yubari Shintanko closed in 1982. This major disaster was a turning point for sustainability of Yubari City, the largest coalfield in Japan. Finally, Yubari City was bankrupted in 2007. This paper aims to explore how miner’s children experienced this disaster and felt about region, family, and themselves, and to explain the relation between region declining and children’s lives. The data of this paper are the archived 600 essays, written by the junior high school students at the time of the disaster. There are three findings. First, the children who lost their father were the most shocked. They faced profound sadness. But they expressed that they had decided to overcome their sadness with surviving family. Second, the children who didn’t lose their father were also influenced. They were anxious about the future of Yubari, their family, and themselves. Furthermore, they decided to strive for their future. Third, they understood the disaster as a turning point of Yubari declining and looked ahead their future outside of Yubari. In conclusion, this disaster created their hopelessness to Yubari region and, as a result, promoted the decline of the city through their migration to other city. Furthermore, it is important to clarify that Yubari City has to continue the struggle to the regeneration.

Jan 1, 2017

By H. C. Verakis, T. E. Lobb

During the past decade, approximately 5 billion pounds of explosives were used annually in the United States. Most of this quantity of explosives was used by the mining industry, with coalmining being the dominant application for explosives. Considering the large amount of explosives used, the accident safety record for the mining industry has improved significantly over the past several decades. Although blasting accidents usually represent a small percentage of the total number of mining accidents, they continue to occur and the severity of these accidents is disproportionately high compared to the other mining accidents. This paper is an analysis and summary of mine blasting accidents over the past several decades as they relate to surface coal mine operations. A compilation and review of surface mine blasting accidents from1978 through 2001 was made. The accident data was examined to identify the trends and primary causes, which continue to be blast area security, fly rock, premature blast, and misfires. Approximately 46percent of the causes of surface coal mine blasting accidents are attributed to blast area security, while fly rock, premature blast, and misfires represented an additional 50 percent of the causes. Accident categories were established based on the cause of the accident or the activity that was taking place when the accident happened. A discussion of the accident data is presented to increase hazard awareness and to emphasize safe blasting practices and MSHA requirements concerning mine blasting operations.

Jan 1, 2003

By Alan E. Isaacson

Extensive gravel deposits exist within a six-county area in the mountains surrounding the Salt Lake Valley, and in the mountain ranges to the west. The six-county area includes Davis, Salt Lake, Summit, Tooele, Utah, and Wasatch Counties. The majority of these are beach deposits from prehistoric Lake Bonneville. However, real estate development associated with a projected population increase of 54 percent over the next 20 years is expected to remove most gravel deposits in Salt Lake County from consideration for mining, forcing gravel operations to relocate from eastern Salt Lake Valley to the Oquirrh and Stansbury Mountains farther west. The gravels in these ranges are of lower quality and require additional processing to manufacture asphalt and concrete. Replacing gravel resources along the Wasatch Front with resources in the Oquirrh and Stansbury Mountains over the next 20 years has the potential to increase construction costs by nearly $1 billion. The majority of this cost (82 percent) is the result of increased transportation costs due to longer distances to market. The remainder of the cost is attributable to lower quality gravels that will require additional processing in the manufacture of asphalt and concrete. The following analysis and discussion does not take into consideration the amount of crushed stone that is currently being used in the construction industry in northern Utah, its use as a substitute for lower quality gravels, or as a factor in the base case projection.

Jan 1, 2001

By L. Watkins, M. O’Kane, A. Weir, D. Portefield

BHP Iron Ore initiated a program in January, 1995 at their Mt. Whaleback operation in Newman, Western Australia to develop a decommissioning plan for the waste rock material. The primary research program includes the development of technology for the long term performance of the waste rock dumps with respect to vegetation, slope stability, surface runoff, erosion, and water infiltration. This paper evaluates field performance of cover systems constructed on a horizontal and a sloped waste rock surface. The cover system is constructed using suitable run-of-mine waste material to minimize closure costs. The moisture is subsequently released to the atmosphere as evapotranspiration. Rainfall entering the waste material is buffered due to the presence of the cover material thereby significantly reducing net percolation to the underlying waste rock. The objective is to control acid rock drainage by preventing moisture movement into and through the waste rock material. Two years of field data are presented to illustrate low percolation rates to the underlying waste rock and key performance characteristics of the moisture store and release cover system design. Field data collected to date demonstrates that a moisture store and release cover system constructed with suitable run-of-mine waste material has good potential as a final acid rock drainage control cover system at the Mt. Whaleback site. The performance of the cover system on a sloped surface was significantly altered as compared to placing the cover system on a horizontal surface.

Jan 1, 2000

By Andrzej Wala

Constantly increasing demand for energy materials and metal ores brought about tremendous progress in mining techniques which are characterised by a high degree of mechanization and concentration of works. One of the recent trends in underground mining mechanization is connected with an application of heavy machines with diesel engines [l],[2]. The introduction of diesel engines in mining all over world caused not only improvement in economic conditions but also the necessity to prevent contamination of air in the mine by toxic agents in diesel exhaust emissions. A generally used way of eliminating exhaust gases is proper ventilation of the cross cut by means of providing permanent exchange of air that would guarantee in every point of the cross cut and in every moment the decay in concentration of exhaust gases beyond threshold limit [3][4][5][6][7][8][9][10]. The present paper is an attempt to define a mathematical model describing the changes of concentration in cross cut face to which fresh air is distributed by ventilators and tubes in a forcing way. Obtained model should offer its practical adaptability to engineering calculation of the amount of fresh air needed for diluting and eliminating exhaust gases beyond threshold limit. Justness of these models has been confirmed by investigation of the growth of nitrogen dioxide concentration in air environment in some cross cut faces of Kiirunavaara iron ore mine in Kiruna (Sweden).

Jan 1, 1980

By K. Norrena, E. Magri

An important problem in mine operations is the classification of material as waste, low-grade stockpile and ore. This classification must often be made with blasthole data that are widely spaced and that have sampling errors. Geostatistical-simulation techniques combined with basic economic principles allow a procedure for classification that maximizes the expected profit. Geostatistical-simulation methods (Gaussian, indicator or annealing-based) allow the integration of hard and soft data in the creation of alternative, equally probable realizations of the mineral grades. At each location, for each realization one calculates the "profit" if the block were to be classified as ore or waste. The optimal classification is the one that maximizes expected profit (a maximum profit selec¬tion or MPS procedure). In this paper, the authors discuss the theoretical justification of the method and implementation details. The use of blasthole data from different types of mineral deposits, that is, different levels of continuity, are considered. The authors also show the efficacy of the procedure with different levels of sampling error. The increased revenue due to the MPS procedure and improved sampling is shown. The paper shows the geostatistical-simulation procedure and the uncertainty in block grades that result from incomplete and imperfect sampling. The optimal classification is presented. Optimal block classifications are transferred to realizable dig limits by hand-drawing polygonal boundaries. The results of the proposed method are compared to classification based on kriging. Limitations and areas of future work are identified.

Jan 1, 2000

By Pieter Barendsen

INTRODUCTION One of the main problems in tunneling without the use of explosives lies in the development of tools which, at an economically acceptable level, are capable of continuous breakage of the rock, resulting in a fragmentation suitable for a smooth, uninterrupted transportation of the muck away from the tunnel face. Tools employed on tunneling machines have, so far, always been of the mechanical kind which break up the rock by a crushing and shearing action. Other methods of rock breaking are possible but, even if some of them have reached the laboratory testing stage, nearly all of them are still too "exotic" to be of any practical use in the immediate future. One must admit, however, that some highly interesting results are beginning to be reported from the USA on the use of high pressure water jets for the destruction of rock through erosion, a field pioneered in Europe(USSR and Great Britain). Mechanical breakage of the rock is effected by inducing stresses exceeding its compressive/shear strength, by loading it with a wedge of cone shaped tool, until cracks are formed and chips loosened. In order to allow the tools to act upon the rock face continuously, they are commonly shaped as rotating bodies, "roller bits" or "disc cutters", spinning freely and mounted on a revolving boring head of tunnel diameter. The thrust of the tools against the face is generally exerted in a direction which is parallel to the tunnel axis.

Jan 1, 1997

By Kenneth J. Miller

Froth flotation is one of the most actively pursued research and development areas in the coal preparation industry today. Many new types of flotation machines and processes are being developed and compared in an effort to handle the increased quantity of coal fines produced by finer grinding for greater liberation of ash- forming and sulfur-bearing mineral matter. Of the many new machines and processes under development for deep cleaning ultrafine coals, it is quite likely that many will not reach industrial use in the near future; in fact, it is quite likely that some never will. Therefore, it is the objective of this paper to select and describe a few of the new flotation machines and processes that appear to have reached a level of development that would suggest their eventual use on an industrial scale. It is probable, and doubtless will be argued, that some of the selections given in this paper should not have been included, while others should have, but the reader must understand that the author is restricted by the information available. And because most of the information available comes from those who are developing the equipment and/ or processes, it is often confusing and conflicting. Thus with a somewhat moderated plan, the author proposes to point out some in- congruities in the literature in the hope that such information might promote more independent study and perhaps explain the abundant promise versus the scant use of the new equipment and processes described.

Jan 1, 1988

By G. Meiers, M. O’Kane

Dry cover systems as a closure option for management and decommissioning of waste rock and tailings is a common prevention and control technique used at numerous sites around the world. Numerous site-specific factors control the long-term performance of dry cover systems. Site-specific climate conditions are one of the key factors to consider when determining the objectives of a dry cover system because these conditions will significantly influence long-term performance. There are advantages and disadvantages of characterizing the site on an annual basis as generally a “dry” site (annual potential evaporation greatly exceeds annual precipitation), or generally a “wet” site (annual precipitation meets or exceeds annual potential evaporation). The field performance monitoring data and discussion presented herein illustrates the caution that is required when using these “annual” criteria for characterizing site climate conditions. Numerous sites exist where precipitation exceeds potential evaporation on an annual basis; however, the site typically experiences hot, dry summer months where evaporation greatly exceeds rainfall. These dry summer conditions have a strong influence on long-term performance. In contrast, sites where potential evaporation exceeds precipitation on annual basis, typically experience periods of the year when a moisture surplus occurs, which also impacts on long-term performance. This paper uses soil-atmosphere cover design modelling and field performance monitoring from sites in Canada, Australia, and the United States to demonstrate the importance of considering site-specific climate conditions when predicting long-term cover system performance.

Jan 1, 2003

By Osvaldo A. Bascur, J. Pat Kennedy

Large metallurgical complexes have more data than a small city and much of it is "real time," changing rapidly as internal and external conditions evolve. As corporations buy and sell assets and reengineer their staff, the structures and tools that were used to understand these data are lost. The lack of an integrated approach makes the profitability of metallurgical plants lag behind that of other industries despite technical advances that have occurred in recent years. This results in significant deterioration in the ability to maintain a "smart” operation. The solution is to use the sophisticated new tools built for the Internet so as to leverage information in a familiar browser format that people can use and understand. Combining real-time infrastructure with portal technology is becoming an accepted methodology. This paper introduces real-time portals and team sites to support decision making by work- groups which require both real-time and documentary information from manufacturing assets, vendors, head office and the Internet. Workers get insight from the overall process effectiveness index based on key variables such as losses due to plant availability, performance efficiency and rate of quality. Real-time portals and smart clients are part of any real-time performance management (RtPM) solution. Three case studies in large metallurgical complexes are presented. PLANTS ARE YOUR STRATEGIC HANDICAP Information technology is arguably one of the fastest moving technologies used by the mining/metallurgical industry. However, the business model for managing that

Jan 1, 2004

By Xingtian Hui

Due to variation in the geological natures of underground coal mines, especially when the entry?s roof/floor are soft and weak, it is vital to select an appropriate roof bolting system to ensure entry stability, coal production, and miner?s safety. No single type of roof bolting system perfectly fits for various types of openings, even within a mine. From the results of continuous research on roof bolting in the past 10 years, the authors used a novel concept of ?Self-screwed? mechanism to develop five types of roof bolting under a patented Self-screwed Tube Bolting System (STBS)©. This roof tube bolting system can be applied to meet different timing-strength requirements under varying mining conditions to increases the stability of mine workings. This paper outlines the structures and mechanisms of the five types of self-screwed roof bolting systems along with their unique characteristics, advantages and disadvantages, and limitations. Two case studies using a Self-screwed Tube Drilling Bolting (STDB)©, one of the five types of roof tube bolting systems, show the principles of mechanics, suitability and parameters for a mine entry and a subway?s construction/ supports in the surrounding soil layers and soft sands, respectively are presented. The results confirmed the time dependent anchorage capacity between predictions and on-site measurements. Currently, other types of the self-screwed tube bolting systems are also being applied to different coal mines in China to increase entry stability and meet safety requirements.

Jan 1, 2009

By Peter Zhang, Daniel Su, Bo Kim, Berk Tulu

This paper summarizes significant findings from the ongoing NIOSH Gas Well Stability research over the past decade; in particular, the important ground control engineering considerations. Longwall-induced surface and subsurface deformations may induce gas well casing deformations and stresses, depending on a few parameters such as overburden depth, overburden geology, topographic relief, strata dip, gas well setback distance, and a gas well casing cementing alternative. Overburden depth to the mining seam is one of the most influential factors; shallow overburden depth induces large horizontal displacement and resulting casing deformation and stress, while deep overburden depth induces large longwall-induced vertical pressure. Overburden geology is another important factor affecting the longwall- induced casing deformations and stresses; the large contrast of bending stiffness at the soft-to-hard rock interfaces tends to induce large casing deformations and stresses. Large surface topographic relief and the presence of soft-to-hard rock interfaces below the stream valley bottoms may shift longwall-induced subsurface gas well casing deformations closer to the surface, thus having less impact on underground. mining operations. Strata dip magnifies longwall-induced deformations by 20% per degree of strata dip for down dip longwall excavations. The gas well setback distance is also a critical geometric parameter; the effect of longwall-induced deformation decreases exponentially as the setback distance increases. Longwall-induced casing deformation and stress will be mitigated or totally uncoupled for uncemented production casing.

Jun 25, 2024

By K. Kavouridis

Coal is broadly recognized as sure, competitive, diversified, not vulnerable and predictable in price energy resource. In power generation coal is playing a dominant role in the EU-27 with 25% of installed capacity and almost one third of the power generation. The role played by the domestic resources and especially by coal are increasingly becoming the focus of the EU energy strategy. There is a strong pressure for the decarbonization of the energy mix. The Emission Trading system (ETs) can have an impact on the shift to lower carbon-intensity fuels. The impact of ETs on coal can be important, because it is very short sighted and only defines the period up to 2008-2012. The ETs CO2 regime must ensure that investment in coal-fired plants in the long term are supported. EU Research Institutes and Coal Industry identified an important CO2 reduction potential by improving the efficiency of the conversion of solid fuels into electricity. Highly efficient clean coal technologies can contribute to reasonable costs and challenge the issue of climate change. It must be pointed out that the EU Energy policy should now concentrate on the necessity to effectively support demonstration projects and to create the legal framework for the integrated approach of efficiency enhancement and CCS. It is not a right approach to implement CCS before the technology is demonstrated and before it is clear that it will be commercially viable.

Jan 1, 2007

By I. Papadopoulos

Nowadays, geophysical prospecting is implemented in order to resolve a diversity of geological, hydrogeological and geotechnical problems. Though plenty of applications and a lot of research have been conducted in the country-side, only a few have been reported in the literature concerning urban areas, mainly due to high levels of noise present that aggravate most of the geophysical methods (e.g. electromagnetic, seismic, gravity etc.) or due to spatial limitations that hinder normal method implementation (e.g. electrical). Among all geophysical methods, electrical tomography proves to be the most rapid and urban noise insusceptible technique. This work presents a case study in the urban area of Hania (Crete I., Greece), where Electrical Resistivity Tomographies (ERTs) have been carried out for the detection and identification of possible buried ancient ruins or other manmade structures, prior the foundation of a building. Nineteen profiles were surveyed in a 20x40m grid using dipole-dipole configuration. The results indicate two areas of interest, that are interpreted as probable old wells, in the context of the existence, in former times and in the same area, of an olive oil plant. In the vicinity, near surface ancient ruins have been disclosed, but no such evidence provided this survey, for the particular area under study and the prospected depth. The collected ERT-data were processed by applying advanced algorithms in order to obtain a 3D-model of the study area that depicts more clearly and accurately the interesting subsurface structures.

Jan 1, 2005

By Alice S. Allen, James Paone

SURFACE SUBSIDENCE IN MINING The consequences of subsidence are becoming progressively more serious as the consumption of an ever- increasing quantity of minerals conflicts with the needs of an expanding population for surface land area. The inevitable result will be an increase in the amount of land area on which undermining is restricted because surface subsidence must be prevented. Designation of land areas that may be undermined, provided that subsidence is controlled and kept within specified limits, also will increase. The decisions as to which land is to be used for urban, agricultural, or other purposes clearly involve considerations that go far beyond the scope of mining technology. Under the authority assigned to the US Bureau of Mines (USBM) by the Organic Act (May 16, 1910) and its succeeding amendments and pursuant regulations (30 U.S.C. 1-1 1 ), the Bureau conducts scientific and technologic investigations concerning mining and its related problems. Subsidence-control demonstrations that have been conducted under this authority include projects in Wyoming, West Virginia, Illinois, and the Pennsylvania anthracite region. The problenls for technology arc to devise methods for extracting minerals with controlled subsidence in varying geologic settings and for calculating or predicting the amount, extent, and characteristics of the subsidence that accompanies the extraction of our principal minerals mined by high-tonnage methods so that logical choices can be made from the possible alternative approaches. Where underground minerals and fuels are mined and removed, the voids that are created underground generate strong imbalanced stresses in the surrounding and overlying rock strata. The resulting readjustments in the rock masses may cause subsidence of the ground surface. Subsidence implies vertical collapse, because the most conspicuous component of movement is downward. However, the downward component is accompanied by differential horizontal strains that may be more damaging to man-made surface structure.; than the more apparent vertical displacements. SUBSIDENCE CONTROL The most widespread method of alleviating potential subsidence problems in undermined areas has been to backfill mine voids with mine refuse or some other in- expensive material that provides lateral support to the remaining mine pillars and vertical support to the mine roof and overburden. Most USBM backfilling work has been conducted jointly with the Pennsylvania Department of Environmental Resources in the anthracite region of northeastern Pennsylvania. These joint projects were conducted under the authority of the Anthracite Mine Drainage Control Act of July 15, 1955 (Public Law 84-162, as amended), and the Appalachian Regional Development Act of 1965 (Public Law 89-4. as amended). In addition to the Appalachian and mine-drainage projects, the Bureau has either conducted or participated in demonstration projects to develop the "pumped- slurry" method of backfilling mine voids. Three of these projects were conducted in Rock Springs, WY. The first was a field test of the pumped-slurry technique, conducted in 1970 under the combined participation of the City of Rock Springs, the US Department of Housing and Urban Development, the Dowell Div. of the Dow Chemical Co., and USBM (Candeub, Fleissig, 1971). The objective was to demonstrate that a large quantity of sand could be hydraulically injected under pressure through a single borehole, and that filling of the mine voids would be essentially complete. In the earlier "blind-flushing" methods, involving sluicing material through boreholes by gravity, quantities per injection hole ranged from 15 to 765 m3 (20 to 1000 cu yd), and the mine voids were only partially filled. In the first test of the pumped-slurry method, approximately 14 900 m (19,500 cu yd) of sand were injected success- fully through a single borehole. Subsequent information obtained through 43 monitoring boreholes indicated that mine voids below 11 330 m2 (2.8 acres) had been filled. As a result of the successful initial test of the pumped-slurry process, USBM conducted additional backfilling demonstration projects using the new technique. The first full-scale demonstration was carried out in the Green Ridge section of Scranton, PA, between 1972 and 1974. This project proved the feasibility of using the new hydraulic-injection technique to back- fill dry mine voids, as well as flooded voids, and it demonstrated that crushed anthracite refuse could be used as easily as sand in the process. Stabilization was pro- vided for about 202 300 m2 (50 acres) of Scranton, having a population of approximately 1000. Additional demonstration projects at Rock Springs, WY, between 1973 and 1975, resulted in the stabilization of about 364 200 m2 (90 acres). The work was necessary to preserve the physical and economic well- being of the city, because there have been numerous occurrences of subsidence during recent years. A demonstration project completed in 1976 in Rock Springs brought the total stabilized area in that city to 647 500 m2 (160 acres). At a cost of about $3,000,000, a population estimated at 7000 persons and property values exceeding $18,000,000 were protected. Presently. USBM is participating in subsidence- control projects involving backfilling in Pennsylvania, Illinois, and West Virginia. Eleven demonstration projects were in progress by USBM in 1977-eight in the Pennsylvania anthracite region and three in bituminous areas of West Virginia (one) and Illinois (two). The estimated total property value is over $100,500,000, and the total cost of the projects is expected to be nearly $20,000,000. The demonstration projects are designed to adapt the pumped-slurry technique to a variety of subsurface conditions, to increase efficiency, and to reduce costs.

Jan 1, 1982

Water conservation and compliance strategy can be cause for success or failure of a new or existing mining operation. Water accounting at outset, and pit and waste dump planning, may not fully consider total inflows, or sediment loads encountered during mine life. Environmental impact assessments, and permitting often dictates the rules, and these may change, to be more stringent, during course of mine development. This paper will identify techniques to control unprojected fresh water, or increased surface water flows in surface mine operations.

Feb 23, 2014