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By Ken Takahashi, Yuuich Umeki, Masahiko Arakawa, Dr. Tominaga. Yuusaku

Macroscopic characteristics of a complicated mine ventilation is remarked to build an expert system for mine safety in the Taiheiyo coal mine, Hokkaido, Japan. To gain the characteristics a large number of simulation were performed with varying aerodynamic resistance of the branches with regulator in mine ventilation network. The principal results of the study are as follows, (1) Pressure loss diagram for ventilation network with main and auxiliary fans enables capability of air circulation in the network. (2) H-Q (pressure-quantity) diagram gives capacity of air quantity In a network with main and auxiliary fans. (3) When airflow rate, [] through branch qi is changed by opening/closing regulator set in the branch, air flow rate, [], through branch p can be represented by the empirical formula. [ ] where Api and Qp,o are the constant coefficients. (4) Macroscopic characteristics mentioned above are available to make rules in an expert system for escaping route at emergency.

Jan 1, 1989

By R. W. Smith, M. C. Fuerstenau, G. X. Xang

Nonliving dried water hyacinth (Eichhornia crassipes (Mart.) Solms) roots were investigated for the biosorption of cadmium, lead and other heavy metal ions from aqueous solutions. Dried water hyacinth roots, when suspended in solution, strongly and rapidly sorb several different metal ions. Factorssuch as reaction time, pH, the initial concentration of metal ions, the presence of other metal ions and biomass concentration were investigated. The adsorption was shown to follow the generalized Langmuir adsorption equation. The relative affinity of the roots for lead is greater than that for cadmium. The batch sorption kinetics of the uptake of cadmium and lead can be described by an apparent first-order reversible reaction model. The roots could be regenerated after the metal ions were stripped. Successful desorption of Cd and Pb from the biomass by acidic CaCl2 solutions revealed that the metal uptake phenomenon is reversible, implying physical sorption of Cd and Pb.

Jan 1, 2000

By Peter N. Loncar

Most miners dream of finding a gold mine sometime during their mining careers, but not very often do such dreams come true. On the tenth day of September, 1962, our dream of finding gold came true when the results of the third drill hole were received. This was undoubtedly one of the most exciting days of our lives. Little did we realize then that this was the beginning of a major discovery destined to became one of the largest gold mines in the country. Discovering and mining gold is not entirely new, however, to Eureka. County a old Lynn Mining District in northeastern Nevada. Since 1900 there has been sporadic activity, mostly consisting of small lode mines and placers. These have produced totally about $300,000; and existence of our orebody would probably have remained unknown had it not been for the United States Geological Survey. The USGS extensively mapped the Roberts Mountain Thrust and published a paper indicating that mineral occurred along this fault and in some places was gold bearing. Utilizing this information, our Newmont Exploration geologists located an area in which: drills were brought in to test their theories. By keeping flexible in our thinning and working, we were able to bring a raw prospect to a producing mine with ore reserves of eleven million tons in a short three-year period.

Jan 1, 1965

By Jasper D. Ward

The Indiana Limestone Company has developed an insulated, thin and comparatively light-weight pane 1 suitable for use as a spandrel panel in a curtain wall. The panel is about four inches thick and is composed of limestone backed with insulation. The inner surface of the insulation is protected with asbestos-cement board or a metal pan, depending on the type of insulation, building-code requirements and appearance (if the surface is left exposed). The limestone is cut to the size of the spandrel openings and the insulation and backup is applied in the mill ready to be shipped and in- stalled in the wall grid, A mortarless and waterproof joint with the metal frame components is achieved through the use of neoprene, thiokol, and caulking, The limestone is "dirt-proofed" (waterproofed) in the mill to slow down discoloration. The panel weighs more than some presently used materials. However, ILCO's architects and engineers have found that curtain wall systems capable of withstanding imposed wind loads are made up of sections large enough to carry this extra load of stone with little or no modification to the size of the metal frame. Limestone, a traditionally sound material, can be used in this new way without losing any of its natural qualities of dimensional stability, resistance to fire, and permanence.

Jan 1, 1959

By J. D. Brown

The purpose of this paper is to inform members of the coal producing and consuming community about techniques used by The Carter Mining Company to control product quality at a large surface coal mining operation. During the early years of mining operations, coal quality received adequate attention but the Company's main emphasis was to build up its production rate and minimize mining costs. While these goals are still of prime importance, coal quality has received substantial attention in recent years. A Company guideline that no coal shipment shall exceed any contract or company-imposed coal quality specification has been successfully implemented. To implement this guideline, geology and coal quality modeling procedures were improved, in-pit drilling and blending programs were refined, and detailed shipment procedures were developed. Background Surface coal mining of subbituminous C rank coal in the Cillette. (Campbell County) Wyoming area has become increasingly competitive during recent years. Prior to 1974, one small surface mine produced coal for local consumption. During the last ten years, 13 new surface coal mines have been constructed. Coal production from Campbell County, Wyoming totalled 88 million short tons (79.8 million metric tons) in 1983, the majority being shipped to electric utilities in the central and southern United States via unit trains having a capacity of 10,000 short tons (9,072 metric tons).

Jan 1, 1984

By W. M. Ma, Daniel W. H. Su, K. Centofanti, Yi Luo, W. L. Zhong, Syd S. Peng

10.1 I~RODUC1'ION In order to understand the effects of surface subsidence due to underground mining on the ground water hydrology, a brief introduction to the rate, direction, and general pattern of ground water movement in aquifers is necessary. Ground water movement in an aquifer is controlled by aquifer lithology, structure, permeability, water levels, topographic set¬ting, and pumping patterns (Sgambat et al., 1980). Fig. 10.1 shows an idealized flow pattern of ground water in a hilly terrain (Coe and Stowe, 1984). The hill is made up of a series of interbedded permeable aquifers (mostly sandstone) and confining units (mostly shale). Since sandstone is porous and permeable, ground water moves through it downward and laterally until it reaches the interbeddings of the confining unit immediately below. The ground water then moves laterally along the interbeddings, be¬cause the confining unit is less permeable, and comes out as springs on the surface at the intersection of the aquifer and the confining unit. If there is a ground water table in each aquifer, it is a perched water table (e.g., right side of Fig 10.1). On the other hand, if the ground water recharge is larger than can be drained out, the interbedded permeable aquifers and confining units will be filled with water and a ground water table will exist only at the uppermost permeable aquifer. This is the semi-perched water table (e.g., left side of Fig. 10.1). There are three ground water flow systems: shallow, interme¬diate, and deep. Shallow flow systems occur near the land surface and the surface drainage system. The flow depth ranges from a few to several hundreds of feet with a resident time of a few weeks to a few years after entry, depending on the permeability of the rock strata. In a shallow flow system, the drainage coincides with sur¬face run-off water divides. Intermediate flow systems occur in minor hills some distance away from surface drainage. The travel distance ranges from several hundreds to several thousands of feet, the travel time from several months to tens of years. These systems are less dependent on seasonal recharge or discharge. In deep flow systems, the ground water travels from thousands of feet to miles, and transfers between surface basins. The travel time ranges from several tens to several hundreds of years. The systems generally receive recharge over a large area on major mountains and dis¬charge into major stream systems. 10.2 CASE STUDIES There are two ways of monitoring water wells for studying the effects of dewatering due to underground mining, i.e., water level and piezometric level. The water level is the water elevation in a water well that has penetrated two or more aquifers. Thus it indi¬cates the combined flow of all the aquifers that the water well intersects during the time of measurement. The piezometric level is the level to which water rises in a piezometer cased to a specific aquifer, and coincides with the pressure level of water in that aquifer. Therefore piezometric level reflects the water condition in that particular aquifer to which it is confined, while the water level represents the total yield of a water well without regard to the source of water. For instance, if a water well intersects two aqui¬fers, and if the lower aquifer is affected by undermining and goes dry while the upper aquifer does not, the water level in the well will drop, but may never go dry. Under this condition, the data obtained by monitoring the water level do not indicate the true behavior of the individual aquifers, especially if they are located at widely separated heights. 10.2.1 WATER LEVEL EFFECTS The effects of underground mining on ground water flow have been the subject of many investigations (Booth, 1984; Coe and Stowe, 1984; Owili-Eger, 1983; Rauch et al., 1984). However, the problems are very complicated, as have been exemplified by the conflicting conclusions reached by various investigators in var¬ious case studies. The most dramatic examples were described by Coe and Stowe (1984). In the first case (Fig. 10.2), the coal seam was 5 ft thick with cover from 400 to 800 ft deep. The majority of water supplies came from a sandstone aquifer in most ridge tops. When the face of the Panel No. 3 passed under it, dug well WW-1, which was approximately 670 ft above the coal, went dry, while the water level in Borehole B- 1, which was located at the center of Panel No. 4 with the bottom reaching the coal seam, also dropped about 160 ft. In Panel No. 5, the developed spring DS-2, which originated from the surface of the sandstone/shale contact and was approximately 750 ft above the coal seam, stopped when the face passed under it. The water level in the dug well W-2, which was dug into the shale about 700 ft above the coal seam dropped about 22 ft, but the well did not go dry. Therefore, nearly every spring or well located above or near the active panels was affected by longwall mining. In the second mine (Fig. 10.3), the seam was 5 ft thick with cover from 200 to 400 ft thick. Dug well DW-2, the bottom of which was 35 ft deep and approximately 330 ft above the coal seam in a perched sandstone aquifer, went dry right after the longwall passed under it. Drilled well W-3, in the sandstone aquifer, about 220 ft above the coal seam, experienced a 75-ft drop in water level when the face was under it, but showed some re¬covery after the face had passed under it. Ponds P- I and P-2 were developed in shale bedrock and were spring fed. They were not affected by longwall mining. Pond P-3 was developed in the sand¬stone aquifer, and its water table showed some decline when the face passed under it. Spring ST-1, which originated from Pond P-1 and was fed from several tributary valleys, was affected by longwall mining, probably because it passed across the panel edges where tension cracks drained off the water. Although the overbur¬den in case 2 was about half of that in case 1, the majority of water resources were not affected by longwall mining. Coe and Stowe (1984) attributed this discrepancy to: (1) a higher percentage of clays, shales, and claystones, resulting in a lesser degree of inter¬connected fracturing, and (2) a less rugged topography resulting in a less localized ground water flow system. Therefore, in order to assess the effects of underground mining, the premining ground water flow patterns, topographical, lithological, and meterological conditions must be known. Booth (1984) also monitored the ground water effects of a longwall mine (Fig. 10.4) in a seam 5 ft thick and 300 to 800 ft deep. There were three major aquifers: Morgantown sandstone approximately 30 ft thick and 630 ft above the coal; Saltsburg sandstone of up to 50 ft in thickness and 520 ft above the coal; and

Jan 1, 1992

By Jon J. Kellar

The adsorption of oleate at the surface of a fluorite single-crystal internal reflection element has been investigated using Fourier transform infra-red/internal reflection spectroscopy (FTIR/IRS). The application of this innovative experimental technique has added a new dimension to the investigation and understanding of collector adsorption phenomena. It is now possible, for the first time, to measure in-situ and in real time the adsorption density and bonding nature of collector species adsorbed at mineral surfaces. In this regard, oleate adsorption densities were calculated from spectral data, and the equilibrium adsorption isotherms were found to agree quite well with other adsorption isotherms reported in the literature. At low equilibrium oleate concentrations(<10-5 M), monolayer-type cover-age was observed in the chemisorbed region. It was found that in this region the adsorption density increases with an increase in temperature, which sup-ports experimental results from previous ex-situ FTIR studies and thermochemical studies in which it was shown that the chemisorption reaction was endothermic. At higher equilibrium oleate concentrations (>10-5 M), the adsorption density increases dramatically at the point of surface precipitation. The oleate adsorbed in the chemisorbed region has a distinctly different spectrum than the oleate adsorbed in the surface precipitation region of the adsorption isotherm. In the chemisorbed region, the oleate appears to be mono-coordinated at the fluorite surface.

Jan 1, 1989

By Kevin A. Foo, Joseph L. Young, William W. Reid

The title of this paper is "Designing Very Large Bio-oxidation Plants". To our knowledge, only one such plant has been designed and built to date, and that is U.S. Gold's Tonkin Springs plant in Nevada. This plant was commissioned in Spring of 1990 and operated for a short time successfully as a bio-leach plant but U.S. Gold did not have the financial strength to overcome the consequences of construction delays and increased capital cost. The plant has temporarily been 1 put on a standby basis. Recently, < > a potential joint venture between Tonkin Springs Gold Mining Company and Homestake Mining was announced. Homestake will operate the mine with the technology and subsequent improvements would be co-owned by both companies. This paper is not a "how to" type publication because we feel that such an approach could be dangerous if used improperly. Rather, we discuss some of the important aspects of process selection, testing and design that need attention, and some of the lessons learned to date. As with all developments, improvements and new knowledge will accrue as more companies use bio-oxidation technology. The Tonkin Springs plant is fair evidence that bio-oxidation has "arrived" as a technology, and that successful design and operation of plants treating greater than 1000 t/d of feed is possible.

Jan 1, 1990

By G. Potts, K. Raiber, T. BoBo

Effective control of balling line circuits is a problem taconite companies have been dealing with for over thirty years. The sensitivity of balling circuits to changes in moisture, bentonite, concentrate particle size, and other operating parameters are the main reasons for control problems. This paper presents test results and describes the integration of existing instrumentation with a digital image analysis system on a balling circuit. This work has the goal of developing control strategies to automatically adjust water spray and bentonite addition, to optimize the size distribution on the roll screen and reduce the variability in control between balling attendants, resulting in more consistent greenball product quality.

Jan 1, 2003

By Jean-François Bougard

It has already been said and written many times that the construction of tunnels in urban areas has proved more and more indispensable, if not vital. The subsequent development of tunnelling for 15 or 20 years has brought large and sometimes spectacular improvements in the fiel of execution methods. But, particularly in urban areas, the difficulties to be overcome have been and still remain very important. As a matter of fact, most of big cities, have been settled near rivers or lakes; therefore the geological nature of the subsoil is soft ground and the level of ground water is high. As a consequence, tunnelling is often faced with many well-known difficulties and dangers issued from decompression or loosening of the ground, sometimes accompanied by a lowering of the water table. This may compromise the safety of the excavation itself and of the workers, and also cause settlements which many severely damage nearby buildings or structures. This is the reason why it is always necessary to work out specially adapted methods and even to develop new ones. In most cases, each work is a particular one and has to be specifically studied since numerous data are to be taken into account, related not only to geology, cohesion and behaviour of the different layers concerned, ground water, the activity of it, but also to

Jan 1, 1979

By Patrick J. Doig

The Crosstown 7 Collector System, Contract C28G11, is part of the Milwaukee Metropolitan Sewerage District&apos;s Waste Pollution Abatement Program. The contract involves the construction of 1.6 km (1 mile) of 3 m (10 ft.) diameter tunnel in soft ground. The tunnel is 10 m (35 Ft.) below surface and passes through a variety of soils. The eastern leg of the tunnel along Bruce Street is mainly in till material, a stiff, relatively dry clay. The northern leg along 16th Street starts in till, and continues in estuarine deposits - moist sticky clay, with intrusions of alluvial sand and gravel. The contract specifications required that the tunnel be constructed either under compressed air or with an earth pressure balance tunnel boring machine. The S. A. Healy Co., the general contractor, chose the latter option. Additionally, a single pass, pre-cast concrete segmental liner was selected as the lining system. The mining machine was manufactured by Lovat Tunnel of Canada and the segments were made by the Sehulster Company of Milwaukee. The use of this combination of machine and lining is relatively new to the United States and this tunnel is the most extensive built to date with a gasketed, segmental single pass lining for transportation of fluids. This paper details the various aspects of the construction of the tunnel and associated shafts.

Jan 1, 1989

By Thomas C. Anderson, Terry Weiss

The Mount Gunnison No. 1 Mine of the West Elk Coal Company (wholly owned subsidiary of ARCO Coal) had secured contracts to provide low sulfur, high Btu steam coal to various utility companies. This called for the development of the B-Seam at the Mount Gunnison Mine located some 400 feet below the operating F-Seam workings being mined with conventional room and pillar techniques. The B-Seam, to meet production goals, will be mined by a new 600-foot longwall machine making a 13-foot high cut. American Mine Services was awarded a competitively bid contract to drive two 2000-foot, 13-foot by 16-foot slopes at -15 percent, sink a 16-foot diameter ventilation shaft 400 feet between the F- and B-Seams, install a 60-inch conveyor in one of the slopes, remove 7000 feet of existing conveyor and rehabilitate 7000 feet in two entries to accommodate the placement of the longwall machinery. The slope portals were located 7000 feet in by the surface portal. Unique to the project was the placement of work shops and other infrastructure 7000 feet underground with an entry height of 6 feet. The $7 million contract was completed in less than one year using a mix of permissible (Schedule 31) and standard (Schedule 24) LHD equipment, all pneumatic jumbos and shaft sinking gear.

Jan 1, 1993

By Carleton K. Smith

Due to special job or client requirements, there will always be some variation in the philosophy of organizing and controlling construction under a project management contract. In typical cases, however, some standard procedures apply. Controls on a construction project are best described only in general terms. They should apply to the total job and can be most effective only when all pieces of the job organization fit together to support a control system for the entire project. Controls are more than a system of reports, schedules, and tabulations-they are the result of an integrated organization dedicated to getting a job done on time and within budget. One of the most important aspects of project control is the construction organization. It must include the right people, facilities, and site equipment, as well as the authority to do what&apos;s necessary to accomplish the work. This should be set up to function with as little involvement from off-site or the home office as possible. However, the jobsite construction group must work within established policies and guidelines and is subject to continuous off-site or home office monitoring. In other words, the job-site leaders need to have a clear definition of their responsibility, their authority, and the necessary people and equipment to make things happen. With that philosophy in mind, this is how Bechtel sets up a new job to be

Jan 10, 1980

By Robert L. Runkel, D. Kirk Nordstrom, James W. Ball

Low-flow reactive-transport processes in Wightman Fork downstream of the Summitville Mine, south-central Colorado were simulated using the OTIS and OTEQ solute-transport models. The simulation was calibrated using data from a synoptic study conducted during October, 1998. Discharge over the 8-km reach from just below the mine site to the Alamosa River confluence ranged from 0.077 to 0.17 m3/s; travel time was 10.7 hours; pH ranged from 4.6 to 5.7. Simulations revealed that mass balance for SO4 was maintained, and that pH, Fe, and Al were non-conservative. Simulations allowing hydrous ferric and aluminum oxide or hydroxysulfate precipitation matched observed water quality conditions more closely than simulations without precipitation.

Jan 1, 2000

By E. Grygiel, J. Haynes, T. McNider

Jim Walter Resources Blue Creek No. 3 Mine was opened in one of the most gassy coal beds in the United States. Although face ventilation requirements exceeded 14,000 cfm (6 .6m3/s) air, continuous miner sections experienced an unacceptable frequency of frictional ignitions. Modifications offered primarily by the U. S. Bureau of Mines such as diffuser fans, water spray fans, and slow speed cutting motors were used with little success. However, laboratory tests conducted at the U. S. Bureau of Mines indicated that an increase in bit attack angle from 50° to 55°-57° significantly reduced the chances of the bit causing a frictional ignition. An experimental miner drum was built using this concept coupled with a new bit designed by the Bureau and manufactured by Hughes Tool Company that better protected the bit steel shank with a carbide cap. It was installed on a continuous miner and placed in an area of the mine prone to ignitions. 50,000 tons (45,500 metric tons) of coal were cut without a frictional ignition. When the miner was withdrawn for rebuild and a machine with an unmodified cutting drum placed in service, two ignitions occurred before 10,000 tons (9,100 metric tons) were mined. Other machines have been rebuilt and are in service, and to date none have been known to cause an ignition.

Jan 1, 1987

By Antonio Peralta

Mining activity in Mexico began in the 16th century when the Spanish realized the mining potential of the new territory. Since that time, mining has evolved into a strong and vital industry for the country. Good professionals in the mining-related fields are fundamental to the growth and improvement of this industry. Since the end of the 18th century, formal education in mining has been available at the University of Guanajuato, in Guanajuato, Mexico. This school created one of the first schools of mines on the North American continent in 1828. In recent times, some other programs have been created at other universities. Universities offering mining related programs Listed here are the seven universities in Mexico that offer mining related degrees. They are the University of Guanajuato, UNAM, the University of Zacatecas, the University of Chihuahua, the University of Sonora, the University of Coahuila and the University of San Luis Potosi. The University of Guanajuato is the only Mexican university that offers graduate studies at the master&apos;s level. No PhD programs in mining engineering are offered at any Mexican university. Programs at each university are of different duration. They are: • University of Guanajuato-Five-and-a-half years, divided into five years of classroom instruction and six months in the working place. • University of Zacatecas - Five years of classroom instruction.

Jan 1, 1994

By G. T. Lineberry, W. J. Wiehagen, L. L. Rethi

This paper discusses a practical method for enhancing the performance of mining work crews. The method, described as the Work Crew Performance Model (WCPM), seeks to define performance variability within similar tasks of an underground work crew. Key components of the WCPM include: •job definition through task analyses, •the ranking of job elements by perceived cost consequence, •observational techniques to establish performance baselines, and •cost linkages between adherence to task procedures and measures of consequence for noncompliance. The components of this model emphasize a reliance on learning from a veteran work force and using that information to reinvest in strategies to enhance safety and efficiency. These strategies are not limited to technological efforts but include consideration of the so-called "soft-skill technologies, " aimed at reducing variability in individual performance and at effecting a continuous improvement in overall system effectiveness.

Jan 1, 1996

By William J. McCloy, Robert L. Gamble

A coal-fired fluidized bed steam generator rated at 12.6 kg/s has demonstrated the industrial and institutional application of fluidized bed combustion by burning high sulfur coal in an environmentally acceptable manner within a populated area. Designed to provide steam for heating and cooling, the unit was placed into service at Georgetown University in Washington, DC, and has already logged 5275 hours.* The unit has consistently operated well within Washington&apos;s strict regulations governing emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), and particulates. The Georgetown program, cofunded by the university and the US Department of Energy, has shown that fluidized bed combustion is a promising way to realize the full potential of coal, the nation&apos;s most abundant energy resource. In a fluidized bed steam generator, a layer of granular limestone is placed on top of a grid designed to prevent particles from falling through. Air is passed upward through the bed with sufficient force to lift and float the particles. At this point the bed material resembles a boiling liquid. Crushed coal is then introduced into the bed and ignited. When high sulfur coal is burned, limestone absorbs the SO2 produced. The operating temperature of a fluidized bed steam generator is relatively low (approximately 871°C). As a result, NO, formation is minimal. Another potential problem encountered in burning coal is fly ash, a form of particulate. A feature of the fluidized bed design, developed by Foster Wheeler Energy Corp., is a fly ash reinjection system. Fly ash is reintroduced into the bed where it is burned again, thereby enhancing fuel efficiency. Nearly all remaining fly ash is captured by a baghouse dust collector. At Georgetown, the fluidized bed steam generator and all auxiliary equipment are enclosed in a structure aesthetically compatible with the surrounding university complex. The steam generator has two separate beds that can be fired independently, and operation to date has been with one and two beds in service, based on steam load demand. During several operating periods, when the fluidized bed unit was the only boiler in service, it supplied all the steam required by the 18.5 hm2 of buildings on campus. Initially fired with low sulfur coal, the unit was quickly switched over to higher sulfur fuel which will be used most of the time.

Jan 3, 1981

By Walter E. Heinrichs

This case history really started during the tail end of WWII when two Navy men, both Colorado School of Mines graduates, got together in Washington, DC, while they were assigned to the Office of Navy Petroleum Reserves doing some of the first aerial magnetometer work ever done on a practical oil exploration basis over the offshore area of the Gulf Coast. When separated from Naval Service active duty in 1946, the two men, Walter E. Heinrichs, Jr., and Robert E. Thurmond, tried, unsuccessfully, to form a commercial air magnetometer business. Later they got together again in Jerome, AZ, with Newmont Mining&apos;s early geophysical exploration endeavors from 1947 to 1949. Subsequent to the Newmont experience, they jointly proposed a specific mining geophysical exploration and development program to Herbert Hoover, Jr., then president of United Geophysical Co. of Pasadena, CA. Mr. Hoover, in consultation with his father Herbert Hoover and others of his staff at United, particularly Edwin G. Schempf, executive vice president, and Raymond A. Peterson, vice president of research, agreed to establish the proposed program under United&apos;s auspices, to be headquartered at Tucson, AZ. The primary objective would be to practically test and develop various mining geophysical methods and techniques while exploring particularly for base metals in the general area of southeast Arizona and southwest New Mexico.

Jan 1, 1991

By H. Köse, C. Tatar, C. Helvaci, F. Simsir

The Çayirhan coal basin is located 124 km (77 miles) west of Ankara,Turkey. With approximately 520 Mt (570 million st) of lignite reserves, the Neogene Çayirhan basin is one of the important coal districts of the central Anatolia region. The Çoraklar formation consists of crossbedded sandstone, channel fill conglomerates, mudstones, carbonaceous shales and volcanoclastic pebblestones, which are fluvial in origin. The lower and upper lignite seams occur, respectively, in the lower and the uppermost parts of the Çoraklar formation. The lignite deposits are in the Çayirhan and Koyunagili portions of the Beypazari Neogene basin. The Çayirhan coalfield consists of lower and upper lignite seams. The lower lignite seam does not outcrop at the surface. Its lateral discontinuity and relatively low sulfur content, plus sedimentologic and stratigraphic features of the associated sediments, indicate a fluvial origin. Thus, the lateral spreading and geometry of the lower lignite deposits were controlled by the channel, flood plain and well drained marshes of a fluvial system. The mining method employed at Çayirhan is the fullymechanized, retreat, working longwall with caving system. Due to ventilation, haulage and tectonic conditions, panel lengths from 0.6 to 1.7km (0.4 to 1.1 miles) are chosen, and 220-m (720ft) face lengths are used. The annual coal production is 2.2 Mt (2.4 million st).

Jan 1, 1994