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By Yukika Miyashita, Takahiro Inoue, Kenji Namikawa, Masashi Matsumoto, Junichi Koseki, Yoshihiro Terashima

"In order to construct an underground two-layer expressway branch junction structure with a height of 14.7 m and a width of 22.3 m, two shield tunnels in each layer were combined by using a non-cut-and-cover enlargement method in sedimentary soft rock. Before and during the construction work, preliminary analysis, in-situ investigations and laboratory tests were conducted to ensure the construction safety and to evaluate the deformation characteristics of sedimentary soft rock. The construction project was safely executed without any water leakage or collapse of tunnel working face. The predicted results from preliminary analysis were almost similar to the measured values. From the detailed investigation of measured results, it was confirmed that the deformation characteristic of the sedimentary soft rock was observed to a small extent as the ground deformation derived from construction work. INTRODUCTION In recent years, some newly constructed urban expressways in Japan are being planned as underground structures due to the consideration of roadside environment. The construction of such underground expressways is frequently conducted using a shield tunneling, a typical one of non-cut-and-cover methods, to prevent any adverse effect to traffic in arterial roads, operation of nearby commercial establishments, and daily lives of local residents during construction work. For underground urban expressway, the connections with existing road network on ground surface or on elevated sections are indispensable, which require the construction of an underground branch junction with large cross-section. This raises a technical difficulty regardless of the open-cut or non-open-cut construction method."

Jan 1, 2016

By D. M. Fritz

Environmental experts face large and rapidly-increasing volumes of raw data obtained from environmental monitoring stations. These professionals must compile and analyze the data in a systematic manner to cost-effectively understand and minimize the impacts of mining. The shift toward desktop computing, combined with the downsizing of company staffs, has now more than ever created a demand for a modern, PC-based application for the storage, retrieval, analysis and presentation of environmental data. This paper discusses the general requirements of such a system, and points out specific ways in which such industry-specific software can provide convenient and useful access to the data. The software used to illustrate these features is the HydroDat program, developed by Western Water Consultants, Inc.

Jan 1, 1996

By M. Ramachandran, R. G. Reddy

"A direct route for the reduction of magnesium oxide to magnesium using thermal plasma processing, with methane as the reducing gas, has been systematically evaluated. A feasibility study of the reduction reaction has been performed on the MgO-CH4 system at different methane concentrations and temperatures. The effects of changes in the key process parameters, such as the oxide-to-methane ratio and plasma power, on the yield of magnesium have been systematically evaluated. A maximum yield of about 61 mol% Mg was obtained using power of 20.0 kW and a molar ratio of MgO:CH4=1:1. Phase, morphological, elemental and binding energy analyses were performed on the product powders to understand the reduction reaction. Surface oxidation was observed in smaller magnesium particles in all the experiments, while the in-situ sintering of magnesium rods was observed at a molar ratio of MgO:CH4=1:1.5. Magnesium carbide (Mg2C3) was observed in the product, and its mechanism of formation is proposed using phase equilibrium data and a predominance diagram.IntroductionMagnesium has an excellent combination of low density and high strength. These properties have increased worldwide demand for and use of magnesium. Two major processes are used in the commercial synthesis of magnesium metal. The first method is electrolytic reduction and the second is thermal reduction using Pidgeon process. These processes can be classified as traditional techniques, but there are numerous emerging technologies that aim at reducing the production cost of Mg, its environmental impact and energy consumption. Thermal plasma processing is one emerging technique that has great potential in all the abovementioned key areas of magnesium production.Traditional reduction techniques. Two major reduction techniques, namely electrolytic and thermal reduction, have been used in the commercial production of magnesium. Electrolytic reduction is typically carried out in electrolytic cells from magnesium chloride (obtained from seawater or well and lake brines) (Tripp, 2009). The following simplified reaction shows the reduction of magnesium chloride to liquid magnesium and chlorine gas:"

Jan 1, 2015

By Henry Chajet

Good morning, it is truly an honor to have been invited to speak before you today Before I begin my update on MSHA's activities, I?d Like t o quickly say a few words about the American mining congress and its mission in Washington, AMC is a national trade association representing most of the producers of the nation's metals, nonmetals and coal, we also represent the manufacturers of mining equipment and supplies and the financial and consulting institutions which service the mining industry. It is the diversity of our representation which gives us our greatest strength in our petitioning efforts, the administration and the members of congress know that an AMC position is the result of the careful consideration of a vastly diverse group of mining concerns. Our president, Al Overton, perhaps has the best description of AMC when he speaks of us as "the mining industry's eyes and ears and its collective voice in Washington."

Jan 1, 1981

By Richard C. Corson

Modern microprocessor systems make it possible to use several variables to anticipate changes in the process and to react with responses before upsets can be magnified by the process or by control action. Through tighter control, "insurance" can be eliminated from process set points without affecting product quality. In actual operation with a traveling grate furnace this control philosophy has produced savings of up to 20% in fuel consumption and 8% in fan power usage while producing a more consistent quality product.

Jan 1, 1982

By D. C. Moore

The decision to proceed on a "fast track" construction project is not" without risks as well as rewards. An understanding of some of the risks prior to start of the project will maximize the rewards. This paper describes the research, development, procurement, engineering and construction of the Asamera Minerals cannon Mine concentrator. This fast track project was accomplished in 20 months. Special attention is paid to the risks encountered and the steps taken to ameliorate them.

Jan 1, 1988

By William A. Griffith

The recent recession has severely impacted the performance and results of virtually all of our natural resource companies. The depressing climate continues to linger and recovery maybe sometime away. Problems remain for resource companies in the steel and petroleum industries as well as the mining business. In February, at the AIME Annual Meeting in New York, an All-Institute session presented a variety of views on the situation. A. T. Yu, chairman of ORBA Corp., Mountain Lakes, NJ, organized presentations by top management personnel of four natural resource companies. This well attended session heard management strategems for the present and views for the future. A compilation and synthesis of these presentations, gathered by Dr. Yu, are presented here for ME readers. Leading off will be William A. Griffith, president and chief executive officer of Hecla Mining Co., Wallace, ID. Other speakers presented here include Wilfred P. Schmoe, executive vice president of Du Pont Co., Wilmington, DE; Frank W. Luerssen, chairman and chief executive officer of Inland Steel Co., Chicago, IL; and Adam H. Zimmerman, president and chief operating officer of Noranda Mines Ltd., Toronto, Ontario. First, then Griffith's remarks. Introduction The key to successfully managing a natural resource company in austere times is good management in good times. In other words, position the company during prosperous times to survive the times when the well dries up. Although we know how to manage properly, for various reasons we sometimes do not do it. We forget the lessons of history. We allow ourselves to be carried away by our egos. We fail to position our companies properly in good times. As a result, in bad times we find ourselves in deep trouble. We need constant reeducation in the things we already know. In the natural resource industries, proper positioning in good times involves becoming a low-cost producer, retaining the flexibility to pull in our horns, developing a lean and effective organization, and maintaining a healthy balance sheet. Nothing improves the chance of survival during austere times as much as being able to produce at a lower cost than your competitors. In our business, that means having low-cost mines - low cost because the ore bodies are high grade or favorably located, and because they are efficiently operated. It also means recognizing the competition. The key numbers are the cost to produce an ounce of silver or gold. Nothing else really counts. And our competition is every other precious metal mine in the world. Flexibility is important when one gets stuck with a high-cost operation, often because things do not work out as we expect. It is important to be able to shut down an operation quickly and easily, without high holding costs, and without disrupting the corporate organization. A lean and mean, effective organization of competent people is vital during bad times. A company will not have that if it is not developed and maintained during good times. Finally, a natural resource company has to develop a healthy balance sheet during good times if it is to survive the bad. Money in the

Jan 6, 1985

By W. G. Lacy

Anticipation of problems and the adoption of corrective measures in the design of engineering structures, establishment of pertinent building codes, and urban planning and zoning to obtain optimum land usage and conservation of natural resources demands a thorough understanding of geological conditions of a developing urban area. In the and to semi-arid southwestern United States erosional and depositional processes result in special situations that require special precautions in building practices. A series of studies currently underway in the Tucson area prompted by foundation failures and breaking, of buried service lines serve to illustrate some of these relationships between the geological environment and history, and engineering problems.

Jan 1, 1963

"Outotec’s TankCell® e500 flotation cell was commissioned during 2014 at the Kevitsa Mine in northern Finland. The TankCell® e500 is the first cell in this size class (500m3) to be run in an operational duty and it has been working as the first rougher in the copper flotation circuit. Treating around 850tph with an average grade of 0.3% Cu the TankCell® e500 has run with an average copper recovery of 71% and an average enrichment ratio of 50. In addition the cell has proved to be very energy efficient, operating with a specific energy of around 0.4kW/m3 under production conditions. This presentation will provide a review of the installation and operation of the TankCell® e500 at Kevitsa and will summarize the results found in the published literature from the various testing campaigns conducted around the cell. INTRODUCTION The TankCell e500 was installed and commissioned at the Kevitsa mine in northern Finland in 2014. Post startup the cell was initially run for testing and optimization with various test campaigns undertaken. but was subsequently taken into a production duty (Mattson et al., 2015a). At Kevitsa the cell is run as the first copper rougher replacing the previous two copper roughers (both 160m3) in this duty. The unit is running at between 38-40% solids at a feed rate of approximately 850tph. Since operational the average copper recovery from this single cell has been around 71% copper. This is typically with an enrichment ratio of around 50 being fed with an average head grade of 0.3% copper. More details on the circuit configuration and production performance of the e500 at Kevitsa can be found in Mattson et al., (2015a) and Murphy et al., (2016). In addition through the optimization program with the use of a variable speed drive controlling rotor speed it was found the the e500 was very energy efficient under production conditions. During this work the cell was found to run at a specific energy of around 0.4kW/m3 which exceeded design expectations (Xia et al., 2015)."

Jan 1, 2016

By Larry Sevenker

On the basis of favorable salt characteristics, primarily compressive strength and impermeability, solution-mined cavities can provide structurally stable isolation chambers for waste. Solution mining techniques are established for storage of hydrocarbons. The proposition of waste isolation in engineered salt cavities is similar to this practice relative to characterization, certification and safeguards. What materials are isolated and how operations are conducted are principle differences. Compatibility of wastes with other wastes must be considered, but hazards can be precluded by avoiding certain mixtures. Waste material characteristics and cavity considerations are discussed.

Jan 1, 1981

By James R. Walsh

While flue gas scrubbing with alkaline solutions is one of the oldest methods of removing SO2 from flue gas, a satisfactory scrubbing system for this application, which is both technically and economically viable, has yet to be developed. Interest in alkaline scrubbing has continued because of its basic simplicity and comparatively low capital cost. Drawbacks of alkaline scrubbing are the tendency for accumulation of solids to plug the system, scaling, corrosion and erosion problems and the need to dispose of large quantities of waste. Discussed are instrumentation loop applications to a 90,000 cfm alkali scrubbing test facility, the process problems the instrumentation engineer faces in. selection of equipment, the performance of the instruments selected and the problems encountered during start-up. The Test Facility incorporates centralized electronic process control with a digital data acquisition system provided to log process variables and print off normal (alarm) conditions. Flue gas SO2 content is measured by ultra-violet analyzers and analysis of the total gas stream is by gas chromatographs.

Jan 1, 1973

By G. C. Van Bever, J. J. Zaluski

Introduction The Surface Mining Control and Reclamation Act (Public Law 9587) (hereinafter the "Act" or "SMCRA") passed by Congress in August 1977 represents a comprehensive federal scheme for controlling surface coal mining and the surface effects of underground mining through permitting requirements, performance guidelines and reclamation planning. While the provisions of the Act have been the subject of numerous legal challenges and court battles over the years, it is difficult to identify a more controversial program within the Act than the provisions for designating lands as unsuitable for surface coal mining operations. The lands unsuitable designation process provides for the acceptance and review of petitions submitted by citizens or organizations seeking to have specified land areas designated unsuitable for all or certain types of surface coal mining activities. In filing these petitions, the interested parties or petitioners are required to make allegations about potential adverse impacts on people or the environment and submit evidence supporting their allegations. In 30 U.S.C. § 1272, Congress provided that "[a]ny person having an interest which is or may be adversely affected shall have the right to petition ... to have an area designated as unsuitable for surface coal mining operations." Under the Act, an area can be designated as unsuitable where the mining operation will (1) be incompatible with existing state or local land use plans, (2) affect fragile or historic lands, (3) affect renewable resource lands where mining operations could result in substantial loss or reduction of long-range productivity, or (4) affect natural hazard lands where such operations could substantially endanger life and property. In enacting SMCRA, Congress mandated that each state establish a process to determine which, if any, lands within the state are unsuitable for all or certain types of surface mining operations. In response to this federal legislation, the Kentucky General Assembly adopted a state regulatory program for surface mining that included provisions direct¬ing the Secretary of the Natural Resources and Environmental Protection Cabinet to establish a program for designating lands as unsuitable for surface mining as required by the Act. In recent litigation in Kentucky, several environmental groups filed a lands unsuitable petition, later joined by the University of Kentucky, challenging a proposal by Arch Mineral Corporation to surface mine over 3 million tons of recoverable coal. The petition sought to designate over 10,000 acres of land adjacent to Arch's proposed operations as unsuitable for surface mining operations, basically alleging that the mining would disturb an outdoor laboratory. The filing of the petition activated Kentucky's regulatory scheme for reviewing lands unsuitable petitions that can result in an absolute prohibition against surface mining on the petitioned land for historical, environmental and other related reasons. The designation process involves vague petition requirements creating a situation that Arch argued is devoid of constitutional due process and subject to abuse by the petitioner on many fronts. Arch maintained that the lands unsuitable regulations do not grant adequate protection to Arch's legitimate property rights under the due process clauses of the United States and Kentucky Constitutions and are thus void and unenforceable. The entire process resulting in a decision on the petition took just under 12 months in the Arch case, and although Arch was ultimately successful in preserving its right to mine, Arch's surface mining permit was held up for this period of time. This delay led to the cessation of mining operations by Arch and the idling of over 250 workers. This paper will review the lands unsuitable designation process and the significant implications the process has for existing surface mining operations, currently proposed operations and even those long-range operations not yet contemplated. Special emphasis will be given to Kentucky's lands unsuitable program. Finally, the recent litigation involving Arch Mineral Corporation and its effort to surface mine 81.5 acres of Arch controlled property will be utilized to illustrate this very unusual regulatory scheme. Regulatory background Chapter 30, Subchapter F of the Code of Federal Regulations (C.F.R.) promulgated to implement the provisions of SMCRA, requires that each state establish procedures under the state's surface mining program for designating non-federal and non-Indian state lands as unsuitable for all or certain types of surface coal mining operations. 30 C.F.R. § 764.1. The C.F.R. establishes minimum standards for state lands unsuitable programs and sets out requirements for filing a Lands Unsuitable Petition (hereinafter "LUP"), processing LUPs, decision-making guidelines and hearing requirements. Kentucky has adopted regulations providing for the implementation of the lands unsuitable process as part of the state's regulatory program under SMCRA. The following discussion summarizes the principle components of the Kentucky lands unsuitable program.

Jan 1, 1993

By Mehmet Guney

[The Atlantis-II-Deep is a hydrothermal mineralization located along the median valley of the Red Sea at a water depth of about 2200 m. Extensive exploration of the metal-rich brine deep revealed a potentially mineable deposit on economic interest consisting of oxides, silicates and sulphides with considerable concentrations of zinc, copper, cadmium and silver. Geostatistics was applied to assess the most likely in-situ vague of the metal potential for economical exploitation. Semi-variograms were constructed to characterize the structure of the regionalized distribution of the geological parameters. Volume grades and thicknesses were determined by the kriging technique, avoiding systematically biased high or low grades, and then block .tonnages were computed. The estimation variances, distribution of errors and histograms of observed and kriged values in each grid Mock were also produced.]

Jan 1, 1983

By Ralph S. Mattson, Frederick T. Hancock

GENERAL DESCRIPTION The Granduc mine is situated on the west side of Granduc Mountain in the Leduc River area of north¬west British Columbia about 51 km (32 miles) north¬east of the town of Stewart. Entry is by means of a 16.6-km (10.3-mile) long haulage adit from the concentrator site at Tide Lake. The principal ore mineral is chalcopyrite. Ore mineralization varies from dis¬seminated to irregular semimassive stringers generally associated with highly folded and sheared biotite-rich sections of metasediments. The ore bodies vary in width from 3.6 m (12 ft) to over 18 m (60 ft) in a zone some 800 m (2600 ft) in length dipping at an average of 75° to the west and plunging steeply to the south. Capping varies in thickness from 0 to over 300 m (1000 ft). SELECTION OF MINING METHOD In the early stages of planning the primary require¬ments to be met by the mining method were: (1) suit¬ability to high output and productivity, (2) adaptability to mechanization in order to minimize operating costs, and (3) minimization of the costs and the development period for preproduction. Considering these, the selection of a mining method was narrowed to a choice be¬tween sublevel long-hole stoping or sublevel caving. A method utilizing backfill was ruled out as uneconomical, especially since mill tailings would not be readily available. At the time, the following facts about the ore body were recognized: (1) the average width of the ore body was 12 m (40 ft), (2) 30% of the stoping blocks were in areas of 6 m (20 ft) or less in width; (3) in many cases, ore zones were located in parallel lenses or were irregular in shape; (4) major faults were present in the hanging wall close to the ore, with minor faults within the different ore zones; and (5) the ore itself was lami¬nated with fractures and jointing crossing such bedding planes. Considering these factors, the two stoping meth¬ods were compared. Sublevel Open Stoping The characteristics of sublevel open stoping are: 1) It is generally not used for widths below 6 m (20 ft) since the ratio of waste development increases as level intervals are reduced to insure good control of long-hole drilling. 2) This method is used where ground is relatively competent. Otherwise more pillar support is required, increasing ore losses or mining costs with pillar recovery. 3) The method is not easily adaptable to parallel ore zones separated by relatively narrow waste bands. 4) Close control of pillar and stope design will per¬mit some degree of dilution control. Sublevel Caving Sublevel caving is characterized by the following: 1) The method can be used for a variety of ore widths, recognizing that 3 m (10 ft) in width may be an economical minimum. 2) It is particularly favorable where wall rock is weak. 3) The method has flexibility so that irregular ore bodies or parallel lenses can be mined. 4) The need to leave pillars for support is eliminated 5) Dilution and tonnage recovery are interrelated. With concern about the stability of the hanging wall and the geometry of the ore bodies, there was a growing favor to choose the sublevel caving method. However, this method was relatively new to Canadian mining practice. Teams were sent to Sweden to tour mines using sublevel caving and to study their methods and any extraction and dilution problems. The objective was to develop cost and performance data and ore recovery grades and tonnages for feasibility comparisons. Next, detailed mine plans were developed covering a three-year period using sublevel caving and sublevel open stoping. Extensive analyses of the development and production costs for each method were made. With sublevel caving, ore losses of 10% with a 20% dilution rate were used. The same ore loss was estimated for sublevel open stoping with dilution varying from 11 to 15%. As a result of these studies, the decision was made to use sublevel caving partly because slightly lower op¬erating costs, together with higher productivity, offset the adverse effects of higher dilution; and partly be¬cause, at the start, there would be less risk in being able to handle the ground, and the method offered more flexi¬bility. Open stoping was not ruled out for testing at a later date. It was recognized that some other method of mining would be required for mining the ore extensions below the glacier, where surface subsidence must be avoided. During the operating life of the mine, open stoping was tested in narrow width ore zones and found un¬satisfactory due to wall failure. A cut-and-fill stope, utilizing run-of-mine waste from development, was also operated on a trial basis. A sequence was finally estab¬lished that permitted ground control; however, produc¬tivity needed considerable improvement in order for open stoping to be considered as a sole alternative for mining below the main haulage level. At the termination of operations in June 1978 over 13 000 000 t (14,500,000 st) had been extracted from above the main haulage level at production rates varying from 3270 to 7250 t/d (4000 to 8000 stpd). Sublevel Caving Methods Two basic methods were used, transverse and longi¬tudinal. The transverse method was used mainly in the upper C ore body in widths greater than 18 m (60 ft), and occasionally as an alternative to the longitudinal method in localized areas where strike faulting inter¬fered with normal development. The longitudinal method was used in ore bodies varying in width from 3.6 to 18 m (12 to 60 ft), with a multilongitudinal varia

Jan 1, 1982

By Lawrence P. Bonicatto

The steel industry's increased demand for higher grade pellets has caused the pellet producers to investigate methods of upgrading their product. The Hanna Mining Company's Groveland plant is no exception. The Groveland Mine is located in Dickinson County on the Upper Peninsula of Michigan. The low grade iron deposit is a complex mixture of magnetite and hematite with chert, quartz, jasper, and various iron silicates. (1) Beneficiation is by Humphrey spirals and anionic flotation of the iron minerals. (2) A general flowsheet is shown in Figure 1. Flotation of the spiral tailings makes up about 75% of the concentrate. A minor amount of concentrate, less than 3%, is produced in magnetic circuits. The concentrate is pelletized at the rate of 1.6 million tons per year.

Jan 1, 1968

By Cleophus Short

[Of the many occupations in and about the coal mines, those of the haulage crews are among the most hazardous. Statistics ship that the second greatest number of fatalities about the coal mines occur during haulage ion and through the use or misuse of haulage equipment. During the five year period between January 1, 1957 and January 1, 1962, the m stone mine had a. Sack haulage frequency of 4098 and mined 3, 541,939 toads per haulage fatality. Coal mire haulage is similar in respects to railroading. We gee very serious consideration to the instillation of tack and to the selection of the haulage crews. In doing this, we are attempting to have our coal mine haulage as. Safe as that of the railroads.]

Jan 1, 1963

By David S. Smith

Almost nine years after the assertion of enormous and pervasive federal control over coal mines by means of the Federal Coal Mine Safety and Health Act of 1969, 30 USC Section 801 et seq, as amended by the Federal Mine Safety and Health Act of 1977 (which basically increases the punitive powers of government) a brief assessment of some of the underlying causes, present status, and possible alternatives to governmental control is appropriate. In a governmental system based upon the principles of democracy and the protection of individual freedoms and constitutional rights the ultimate mechanism for abrogation of these rights is the creation and exploitation of fear. Machiavelli in rendering advice concerning the power over men provided by fear stated, "... it is much safer to be feared than loved .. fear preserves (the government) by a dread of punishment which never fails." The Prince. Within the context of the assumption of control by the government over industries or segments of our population - popular fear provides a convenient and almost necessary mechanism for the avoidance by law or regulation of democratic principles. The popular fear of coal mines has been successfully exploited by various goal oriented groups in the past and most recently by a Congressional constituency with a vested interest in controlling the mines through regulation.

Jan 1, 1979

By Guy Reed, Russell Frith

In situ or pre-mining horizontal stresses are arguably the least well understood of the principal inputs into underground coal mining geotechnical engineering design, whether analytical, empirical, or numerical. This is a direct result of both the cost and difficulty of obtaining meaningful stress measurements, the various limitations of the measurement method in terms of sourcing strata types that approximate the assumed conditions of the post-measurement mathematics to convert measured strains into stresses, and a common practice by some geotechnical professionals to preferentially utilise generic values rather than interrogate the available measurement data for cause and effect relationships between horizontal stress magnitudes, directions and a range of associated controls. That numerical modelling simulations attempt to mimic reality but often rely on simplified generic horizontal stress input assumptions is a particular cause for further consideratio The paper attempts to further explore the nature of in situ horizontal stresses using a range of stress measurement results from the Australian coal sector supplemented by several international studies addressing the same basic issue, the result being a number of credible and highly relevant “cause and effect" inter-relationships between the three principal in situ stresses in addition to the influence of rock properties (e. Young's Modulus and Poisson's Ratio), cover depth and the larger-scale structural geological environment. In particular, the paper demonstrates that despite being commonly overlooked as a primary rock/coal material property, Poisson's Ratio and the associated K Effect are intrinsic to understanding 3D in situ stress measurement results and therefore, predicting in situ stress magni- tudes more generally for geotechnical analyses purposes. As a fundamental question, the paper addresses whether it is necessary and of engineering value to characterise in situ horizontal stresses: according to distinct "domains," in the same way that more easily identifiable geotechnical properties such as rock mass ratings, coal seam thickness, ply splits, and cover depth are often treated.

Jun 25, 2024

By D. A. Fenton

The reliability of large diameter, high horsepower ball mill is paramount when large production and minimum downtime is required. The 17 ft. x 56 ft. double compartment ball mill at St. Lawrence Cement Company has the first gearless drive built in North America and has the world's largest hydrodynamic bearings currently built and running. The machine has seen three years operation and has met its specifications. The mill was designed by Aerofall Mills Limited and the gearless drive built and designed by the Canadian General Electric Company. This paper discusses the operation of the first North American installation of a gearless drive ball mill from the mechanical, electrical and process aspects.

Jan 1, 1977

By C. C. Stewart

Jim Walter Resources, Inc. operates four underground coal mines in Alabama. In 1986, during longwall recovery operations, sparks from a torch ignited methane that migrated onto the face after a roof fall. The fire quickly spread to the gob at the tailgate end of the longwall. The fire was successfully "area" sealed and mining operations resumed after five weeks. However, several problems were encountered during this process. This paper describes the events following the fire, methods used to control the situation, problems encountered, and steps taken to ensure preparedness for any future occurrences of this type.

Jan 1, 1993