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By Gregory M. Rumbaugh, Christopher Mark

"The proliferation of unconventional gas well development in the Northern Appalachian coalfields has raised a number of mine safety concerns. Unconventional wells, which extract gas from deep shale formations, are characterized by gas volumes and pressures that are significantly higher than those observed at many conventional wells. The gas is composed largely of methane as well as other hydrocarbons. Hundreds of planned and actively producing wells penetrate protective coal pillars or barriers within active mine boundaries, including chain pillars located between longwall panels. Gas released from a well damaged by mining-induced ground movements could pose a risk to miners by flowing into the mine atmosphere. The mining-induced ground movements that may cause well damage include conventional subsidence, non-conventional subsidence (e.g., bedding plane slip), pillar failure, and floor instability. This paper describes the known risk factors for each of the four failure mechanisms. It includes a framework that can guide the risk assessment process when mining takes place near gas or oil wells.INTRODUCTIONSouthwestern Pennsylvania has served for centuries as a producer of coal, oil, and natural gas. Coal mines were first developed in the Pittsburgh Coal Seam in the 1760s, with the first recorded mine in 1761 being the Fort Pitt Mine (Edmunds, 2002). Natural gas was introduced to the region when the Haymaker Well in Murrysville, Pennsylvania experienced a blowout on November 3, 1878. Although it was originally drilled prospecting for oil, it produced an estimated 30 million cubic feet per day of natural gas. Without well controls or pipeline infrastructure in place, it burst into flames and lit the night sky for over a year. Soon after, the Penn Fuel Company continued development of the Murrysville gas field and is credited with making Pittsburgh, Pennsylvania the first major city in the U.S. to have natural gas supplied for home and industrial uses. “Natural gas is king in Pittsburgh,” proclaimed an October 18, 1885, article in the New York Times headlined “Value of Natural Gas, Its Use Clarifies the Atmosphere at Pittsburgh” (AOGHS, 2018). By the early 1900s, coal, oil, and natural gas production had reached the southern extents of Pennsylvania in Greene County. The county had first produced oil in 1886, and shortly after began producing natural gas in 1890. By 1906, over 1,300 wells had been drilled (Stone and Clapp, 1906)."

Jan 1, 2019

By Don Reining

The sand and gravel industry in Southern California has made a sizeable contribution to the construction development of the 15 County area in this part of the State. Facing this mineral extraction industry, in the next decade, is a problem of meeting the market demand. The question is, "how can sand, gravel and rock operations be made compatible with goals for sound and attractive community development?" Three basic principal characteristics of the land needed for this-mining industry are: 1. The land must have workable sand, gravel or stone deposits. 2. The land must be properly located for transportation purposes close to the market in order to sell the aggregate at a minimum cost. 3. The land must be zoned so that it will be permissible to mine.

Jan 1, 1967

By L. Adler

A fairly complex analysis is required to select, or evaluate a piece of excavating and bulk handling equipment and obtain its performance. At present there is little agreement as to what specific points should be considered, and even less on what procedure to follow. This paper provides both of these in a consistent and direct form. The analysis applies to all types and sizes of equipment from the bulldozer and the continuous miner, to the B.W.E. The importance of the equipment characteristics, job activities, and work conditions are stressed and separate analytical stems are established in a flow chart for these. They are combined using suitability tests in the following steps: 1) problem statement, 2) natural conditions, 3) suitability guidelines, 4) appropriate equipment types, 5) operational activities, 6) encumbered space, 7) geometric design, 8) equipment sizing, 9) failure and limits, 10) performance and consumption, 11) public policy checks, and 12) costs and profitability. Public policy and economics while considered throughout receive emphasis towards the end. The procedure is iterative, containing distinct feedback loops. Specifying the steps and sequence provides a necessary structure which has long been overdue.

Jan 1, 1983

By Donald P. Richards

Is a shaft the same as a tunnel and can it be approached in the same manner for design and construction? The most obvious difference between a shaft and a tunnel is that of orientation; whereas a tunnel is commonly near horizontal or slightly dipping, a shaft is commonly vertical or steeply inclined. As a result, design and construction methods employed for tunneling, in general, cannot be directly applied to shafts, although some of the basic concepts of behavior are quite similar. Many of the shafts that have been sunk in various parts of the world are owned by private mining companies. Each company has generally accumulated years of experience in shaft sinking and mining techniques pertinent to its particular geographic location. When a new shaft is to be sunk or an existing shaft deepened, the tendency often seems to be to continue to use the methods that have been used successfully in the past.

Jan 1, 1979

By JURGEN KRETSCHMANN

The European climate and energy framework for 2030 is highlighting the reduction of man-made CO2 by increasing the use of renewable energy. In this spirit, Germany has decided to erase coal use as an energy source by 2038 completely. This strategy premises a feasible, responsible and sustainable post-mining management. The Research Institute for Post-Mining (FZN) at the TH Georg Agricola University in Bochum, Germany, has developed a holistic approach to meet post-mining challenges. In all efforts, the FZN aims to achieve the fundamental goals of the United Nations to deal with the resources of our planet responsibly and sustainably.

By Dale S. Hursh, William A. Brooks

Introduction US dependence on external energy sources is dangerous because of unstable political situations existing in key energy exporting countries. So, recent national energy policies call for increased reliance on domestic energy sources. Coal ranks as the most feasible domestic energy source due to its abundant reserves and continental distribution. But to efficiently extract these coal reserves, huge sums of capital funds are needed. Due to the depressed economy, lenders of capital funds are forced to be more stringent with loan applications. This results in fewer loans granted. In many cases, it is uncertain if funding can be obtained. Furthermore, the greatest level of domestic mine financing is expected to be in the coal sector. Demand for capital in the domestic coal industry is anticipated to increase 80% by 1990. The Chase Manhattan Bank in New York warns that these future needs cannot be met by the present capital markets. This article analyzes the current and expected situations of the capital markets available to the domestic coal industry, including: • current and expected future types of financing used in the domestic coal industry; • problems the domestic coal industry may encounter as it seeks capital; and • the future availability of capital funds as concluded from analysis of the first two items. Background Information Regardless of industry, all projects or ventures can be divided into four basic stages: generation; evaluation; selection; and execution. Within the mining industry, one can break down these stages to draw a clear picture of mine development, as shown in Fig. 1. Each successive stage has a corresponding risk level. This risk level defines the type of financing available to the mine operator. Mining Venture Risks A coal mining venture can be characterized by its unique blend of technical and financial risk. As the mine moves through different development stages, varying proportions of each of these risks are encountered. It is these risks that the lender evaluates to determine project suitability. For a coal mining venture, the major complexities generally occur with the technical risk. These include: • quantifying the coal reserves: • assessing the feasibility of the mining method; and • evaluating the design of the wash plant. The reserve risk is gauged by the amount of measured, mineable, and saleable reserves. The greater the latter amounts, the lower the risk. Secure title to the reserves plus title for any surface areas required are also of concern to the banker. Feasibility of the mining method and evaluation of the wash plant design should verify that the project can be completed according to the engineered spec-

Jan 9, 1982

By K. L. Kayler

Ball clay production in 1991 amounted to about 800 kt (880,000 st), about the same as in 1990. 1992 estimates show a 5% decrease to 750 kt (827,000 st). This decrease continued a trend of reduced production that began after the peak of 900 kt (1 million st) that occurred in 1988. Use of ball clay in sanitary ware was about 2% less in 1992, although levels of use in floors and wall tile, dinner ware and pottery remained constant. Filler, extender and binder applications continued to be important end uses, accounting for about 17% of total market. Refractory uses maintained their market share of about 17 kt (18,700 st). Use of clay liners in toxic and waste dumps is an application widely found in Germany. However, its use has not been fully exploited in the United States. This could represent an opportunity for domestic clay producers. Tennessee remained the leading source of ball clays. Other producers were Indiana, Kentucky, Mississippi and Texas. Tennessee's production, however, decreased about 3% in tonnage produced and its value dropped from 68% to 65% of total production. The ceramics division of Southern Clay Products, Inc., was bought from LaPorte plc by United Clays of Texas, Inc., a US subsidiary of Watts Blake Bearne & Co. The purchase included ball clay reserves at Troup, TX. The acquisition makes United Clays the second largest ball clay producer in the United Sates. United is also the only company mining clay in Texas. Fire clay production decreased 5%

Jan 1, 1993

?Classification System Efficiency (CSE)? is a simple, powerful concept which can be used to measure and improve ball mill circuit efficiency. This paper describes six plant case studies which demonstrate the use of CSE to diagnose and/or improve grinding circuit performance, with related improvements in circuit efficiency ranging from 3 to 30 percent. The increased effective mill grinding energy is recaptured from energy that was going into over grinding, which can greatly benefit downstream mineral separation. The achievable CSE for given circuit design/operating variables is described, providing every plant metallurgist with the means to determine the potential for increasing their particular grinding circuit?s efficiency through increased CSE.

Jan 1, 2012

By A. Benchekroun

The phosphate mining industry is confronted everywhere in the world with financial difficulties and low prices which prohibit further investments and development of new mines even in regions with a comparative cost advantage (North America/ North Africa/ and Middle East). But old mines are being progressively exhausted/ and if no replacement mines come on stream in the near future/ we may soon find ourselves (around the year 2000) with a global annual production capacity of 160 million tonnes of marketable phosphate rock instead of the capacity of 200 million tonnes existing today. Unless prices improve/ phosphate rock/ a non-renewable resource and a vital commodity to world agriculture/ may turn to be in short supply to world fertilizer industry. Whatever the extent of recovery of fertilizer demand/ the expected decline of the production capacity during the 1990 I s is bound to cause the disappearance by the year 2000 of the important surplus characterizing today the supply/demand balance.

Jan 1, 1995

By V. A. Evans, D. L. Hellier

Introduction Preparing a report on fluorspar economics in the US could have been somewhat complicated at one time. This was because the number of producers, both large and small, derived production from different locations through-out the western US and the southern Illinois and western Kentucky fluorspar districts. Companies, such as Allied Chemical and Williamson Mining, operated in the Jamestown district of Colorado. In Walden and Salida, CO, the Colorado Fluorspar Co. operated mines and mills. In New Mexico, both Du Pont and Allied had mines and mills. In the Illinois-Kentucky district, US Steel, Rosiclare Lead and Fluorspar, Minerva Oil Co., and Marathon Oil all produced spar for the US market. Now all of the companies are out of the fluorspar business and, with the closing of the Seaforth Mineral Co.'s Inverness Mining Co., only Ozark-Mahoning Co. survives as a domestic producer. History Ozark-Mahoning Co., as it now exists, was formed in 1946 by the merger of Ozark Chemical Co. and Mahoning Mining Co. Ozark Chemical Co. was started in the 1920s to produce sulfuric acid for two refineries located in Tulsa, OK. Mahoning Mining was originally formed by the founders of Ozark Chemical Co. and the Youngstown Sheet and Tube Co. to produce fluorspar and associated minerals from properties in the southern Illinois and western Kentucky fluorspar district. In 1937, Mahoning Mining started an exploration program, employing contractor-operated churn drills to look for reserves in Hardin and Pope Counties in southern Illinois. Based on known reserves in the area and the results of the exploration program, work was started in the fall of 1938 to build a selective flotation plant at Rosiclare, IL. The mill was completed and put into operation in August of 1939. The company's first mining efforts were in the Cave-In-Rock district just north of Cave-In-Rock, IL. The deposits in this area were of the Manto or bedded type. They have been the mainstay of the company's operations in the Illinois-Kentucky fluorspar district. In 1950-51, the company expanded its operations by purchasing fluorspar properties from Colorado Fluorspar Co. at Walden, CO. This location was operated from 1952 through 1958 and from 1968 through 1973 when it was closed permanently. In 1974, Ozark-Mahoning Co. was purchased by Pennwalt Corp. Presently, it is a wholly-owned subsidiary of that corporation. As the only major domestic producer of fluorspar in the US today, the company's ability to survive under the flood of imported material is directly related to the four major segments of its operations. These are: exploration, mining productivity, maintenance, and marketing. All are done in-house. Exploration The Southern Illinois fluorspar district is located in the most complexly faulted area of the central US. The formations are sedimentary in nature and range in age from Devonian through Pennsylvanian. The deposits are small, they range in size from a few thousand tons up to 900 kt (1 million st), with the average minable deposit being around 544 kt (600,000 st). The ore occurs in both nearly vertical vein deposits and in Manto or flat lying bedded deposits. Due to the relatively small size of the deposits and the depth at which they occur, a good low-cost exploration program is essential to ensure that new finds of ore are equal to the mining extraction rate. Ozark maintains a leased land position in Pope and Hardin Counties that will fluctuate somewhere between a low of 40 km2 (10,000 acres) up to a high of 129 km2 (32,000 acres), depending on total size of tracts leased. Most all lands are obtained through a standard lease purchase option, with a small minimum royalty per acre during the normal 10-year option period. All leases are standard and without deviation to control land cost. All land leasing is done through Ozark's geological staff, who also

Jan 11, 1986

By James T. Baxter

Underground mining of limestone is becoming increasingly attractive in Illinois. Most quarries are near rivers on the western and southern borders where competition for land use is intensive. Increasing demands for stone can be met by expanded mining with access by edits in existing quarries and by inclines and shafts at downdip sites. Geologic, hydrologic, and engineering conditions indicate that deep mines in the Ste. Genevieve, St. Louis, Salem, Ullin, and basal Burlington Limestones of Mississippian age and in the Moredock Limestone Member of the Dunleith Formation of Ordovician age are possible, but development will require prudent exploration and planning to ensure that the product will be of good quality.

Jan 1, 1978

By David Kress

Mill crushing drive systems are essential to cement producers. With the increased emphasis on operating efficiency, it is vital that these systems be dependable and reliable. No one needs the costs or headaches associated with unscheduled downtime or inefficient machinery operation. A reliable drive system starts with the proper selection of the ring, or girth, gear and continues through proper maintenance. Ideally, selecting the right girth gear brings together the gear manufacturer, the system designer and the end user. The gear manufacturer must know the details of the application, the demands that will be placed on the gear and the nature of the equipment to be driven. Similarly, the user and the system designer must be familiar with the variables that affect gear drive performance and service. For example, an application that places a torque load on the drive in excess of its rated capacity will result in gear tooth distress and, in severe cases, breakage.

Jan 1, 2000

By Leo Wagner

In relation with the construction of the Sölk power station in Steiermark, Austria, tenders were called in October, 1976, for the construction of the 12-km "Donnersbach collector tunnel" by "Steirische Wasserkraftund Elektrizitäts AG". The specified showed both conventional blast tunneling as well as mechanical excavation with a tunneling machine, diameter 3.55 m. Total construction time from the date of the invitation to tender was given as 4 years. Part of the project was the construction of a concrete circular tunnel lining 20 cm thick. In 1977 the contract was awarded to "Arbeitsgemeinschaft Donnersbach", a joint venture formed by two companies, G. Hinteregger & Söhne, Salzburg, and G. Hinteregger, Bregenz. It provided for the project to be carried out with a tunnel boring machine. GEOLOGICAL DATA The entire tunnel was to be bored through a complex of the garnet mica schist group of the Wölz schists formations. These range from highly quartz-bearing to quartzitic mica schists, with thick, discordantly interstratified beds of marble and dolomite. In the western sector the axis of the collector tunnel intersects the bedding at an angle of 30° to 40°, in the eastern sector the bedding is about

Jan 1, 1979

By Leonel Lopez

Throughout Mexican history, mining has been an important, traditional activity. Before the "Discovery of America," native miners worked a variety of deposits throughout the country, including Mixtec gold and gem mines in Oaxaca State and Aztec gold, silver and copper from mines in Michoacán. The 500th anniversary of Mining in Mexico after the "Discovery of America" was initiated by the Mexican mining sector on April 15, 1991. As early as 1548, when the Guanajuato mining district was discovered, Mexico had become a leading world producer of precious metals. Since then, Mexican mineral production has developed in cycles, responding to changing technological, economic and political conditions. During the 20th century, Mexican mine output reached its peak in the decades of the 1930s and 1940s, when it was producing about 40% of the world's silver, 15% of its lead, 10% of its zinc, 4% of its copper and 3.5% of its gold. In 1990, by way of contrast, these percentages of world output stood at 13.5% for silver, 4.7% for lead, 4.1% for zinc, 3.2% for copper, and 0.43% for gold. The lowest production levels were recorded during the 1960s and 1970s, when Mexicanization of the industry and increasing state controls weakened mineral economics to a point that mineral exploration budgets were sharply reduced or eliminated, along with the industry's future. Only the noble old mining districts continued to supply production, with occasional eruptions of "bonanzas" and new extensions in established mining districts.

Jan 1, 1994

By Avula Rajashekar Yadav, Sreenivasa Rao Islavath

Barrier pillars and gateroads play a vital role for the safe exploitation of coal from the panel in the longwall workings. The barrier pillars and gateroads are subjected to the front abutment and side abutment loads during the retreat of the panel. These structures may fail if the developed load on them is higher than their strength. The stability of the longwall structures such as barrier, gateroads and face is paramount in extracting the coal from the panel safely. For this, a deep longwall mine in India is chosen for the study using a 3D numerical modelling technique. In this paper, three critical conditions such as scenario 1 (no side goaved-out panel), scenario 2 (with side goaved-out panel) and scenario 3 (with two side goaved-out panels) are taken. For each scenario, five retreat distances such as 100, 125, 150, 175 and 200 m are considered for detailed investigation. The development of vertical displacement in gateroads, vertical stresses on barriers, vertical stress concentration factor, abutment zone and yield zone for longwall face are extracted and analyzed. Also, the safety factor of the barrier and longwall face is estimated considering the Hoek–Brown rock mass failure criterion. From the study, it is observed that the maximum vertical displacement of 121 mm in TG3 at scenario 3 for a retreat distance of 200 m and a minimum vertical displacement of 33 mm in TG2 for a retreat distance of 100 m at scenario 2. The development of vertical stress on the barrier is found to be between 8.78 and 13.40 MPa, and the safety factor of the barrier lies in between 1.56 and 1.80. The study also revealed that the yield zone at the longwall face lies within 2 to 3 m.

Dec 29, 2023

By J. Wickens

Haile Gold Mine is located near Kershaw, South Carolina, approximately 50 miles south of Charlotte, North Carolina. Gold was first discovered at the site in 1827, and the property has been through several operating periods since. The relatively low grade and refractory nature of the deposit has been a challenge for efficient processing since the start of mining on the property. Early processing techniques included gravity separation and barrel chlorination. The last operation employed heap leaching in 1985 through 1992. After being closed and reclaimed for over 20 years, the property is poised to re-open and produce once again. In this chapter of the Mine?s legacy, flotation and ultra-fine grinding will be employed to achieve economic extraction of gold and silver from the pyrite. This paper briefly reviews some of the mine?s history, the metallurgical testing, the flowsheet and discusses design considerations. KEY WORDS: process plant, flash flotation, leaching, SMD, stirred media detritor

Feb 27, 2013

By Dave Southworth

After Abe Lee discovered gold (in April 1860) near the site of present-day Leadville, Colorado, he and is group staked nearly all of California Gulch with "speculative claims." They did so in an effort to grab any property that might be potentially profitable. But the plan did not work. New prospectors demanded a miners' meeting, from which arose the official "Bylaws of California Mining District, California Gulch, Arkansas River." These bylaws, adopted on May 12, 1860, established provisions as to the number, size and type of claims that could be filed. Fair laws invited more newcomers. By mid-summer, 5,000 people with tents and wagons were scattered from one end of the gulch to the other.Among the earliest arrivals to the region that spring were Horace Austin Warner Tabor and his wife, Augusta. H.A.W. Tabor, who was to become a pillar in the development of Leadville, arrived at California Gulch during a food shortage. He sacrificed his oxen so that hungry miners could eat. By doing so, he immediately became the friend of many. Augusta established a little store where she sold her baked goods and provided meals. Like most of the men, Horace prospected the surrounding hills. He only did so, however, for a short time. California Gulch yielded more than $5 million in gold during the next five years. By 1866, however, the placer gold was gone and most of the miners had packed up and left. Charles J. Mullen and Cooper Smith, who were grubstaked by a Philadelphian named J. Marshall Paul, found a new, rich lode at the Printer Boy Mine in 1868. It was the first underground gold mine in the Leadville area and marked the transition from surface mining to underground hard rock mining. Its discovery created a new but modest flurry of activity. Heavy black sand covered the region and made gold mining difficult. In 1875 William Stevens and Alvinus Wood decided to have the sand assayed. They discovered that it contained 15 ounces per ton of silver and was rich in carbonate. Stevens and Wood kept their find a secret for nearly two years. When the word spread in late 1877, the silver boom was on. In 1878 prospectors, merchants and others trickled into town from all directions. Dr. David H. Dougan closed his office. in Alma, crossed Mosquito Pass and set up shop in Leadville. Nobody seemed to need a doctor, however, and Dougan sat in his office for 28 days without a customer. On the 29th day he received word that there had been a mining accident and he was needed immediately. -That was the begin¬ning of his illustrious career in Leadville. Dougan was a successful physician, became mayor in 1881 and was later president of the Carbonate National Bank. Leadville was a simple community of log structures in 1878. By June of the following year, however, it had blossomed considerably. According to Cass Carpenter, as of May 1,1879, Leadville had "...19 hotels, 41 lodging houses, 82 drinking saloons, 38 restaurants, 13 wholesale liquor houses, 10 lumber yards, 7 smelting and reduction works, 2 sampling works for testing ores, 12 blacksmith shops, 6 livery stables, 6 jewelry stores, 3 undertakers and 21 gambling houses where all sorts of games are played as openly as the Sunday School sermon is conducted." Additionally, there were 36 brothels. When George E. King and other architects arrived, Leadville took on an air of elegance and sophistication. In sharp contrast to some of the Victorian-style, gingerbread-laced homes in Leadville, its suburbs were comprised of many tenement shacks and plain cabins mixed with a few commercial buildings, many mines and smelters. Mines sprinkled the area east of Leadville like pepper from a pepper shaker. Wherever there was a cluster of mines, a camp usually sprang up. Most were very close together. South of Leadville the giant Arkansas Valley lead smelter sprawled out between Stringtown and Bucktown in an area known as Smelter Valley. Founded in 1879 as the Billing and Eilers Smelter, the Arkansas Valley plant was operated by the American Smelting and Refining Company. Several other smelters operated in the vicin¬ity. In April 1878, Horace Tabor grubstaked prospectors August Rische and George Hook. For $64 worth of supplies and tools, he was guaranteed a one-third interest in their findings. Rische and Hook discovered the Little Pittsburg (often spelled Pittsburgh) Mine and made Tabor an instant millionaire. Tabor once purchased a "salted" mine, the Chrysolite; but instead of considering it a bad deal, he further developed the property and struck rich silver ore. Later, Tabor purchased the Matchless Mine for $117,000, possibly the only investment he made without partners. During its peak years, the Matchless yielded $1 million worth

Jan 1, 1998

By Donald R. Williamson

The Cyprus Pima Mining Company's open pit operation was started in 1957 with the normal assumption that the ore reserve estimate was accurate within an acceptable range of values. At that tine reserves were law - volume (+10 million tons) and high grade (+1.5% Cu). Several periods of growth have brought the operation to its present production level of 55,000 tons per day of ore and +125,000 tons of waste. Over the years, a number of attempts to refine and polish the ore reserve figures have been made using a variety of established standard procedures. None of these attempts have produced results which are totally satisfactory, particularly when comparisons are made between ore reserve estimates and short to medium range production figures. Other refinements were tried using adaptations of established methods combined with computer modeling techniques. The resulting mine-model ore blocks were an improvement but they still tended to show too match tonnage of mill feed, often at too low a grade. One attempt at Kriging had only limited success. Statistical studies of operations data revealed relationships which could be used to subdivide ore blocks in much the same way as they are actually mined. Comparisons thus far between these newly developed ore blocks and production data show that the new method of evaluation yields excellent results. A new, better procedure for estimation of ore reserves apparently has been developed for the Cyprus Pima deposits. The specific procedures seem likely to have direct application to other, similar operations. The methods used to develop the procedures could be of value to still other operations.

Jan 1, 1976

By Mike Wongkaew, Brandon Kluzniak, Per Vilhelmsson

Rail access to Ontario International Airport (ONT) has long been a goal of San Bernardino County Transportation Authority (SBCTA) to increase public transit options to ONT and provide incoming ONT passengers improved access to San Bernardino County and the greater Southern California region. This paper describes the planning for the Design-Build-Operate-Maintain (DBOM) delivery of an emerging technology tunnel connection between the Rancho Cucamonga Metrolink station and ONT. The paper discusses key technical considerations, challenges, and opportunities; conceptual configuration development; and construction planning and establishment of the footprint for the underground connection.

Dec 1, 2022

By J. Kern, T. F. Torries

Identifying high value areas of unmined coal when large quantities of coal are available relative to annual markets is difficult because of the uncertainty of when the coal is to be mined. A GIS based methodology developed to value reserve coal in a producing coal region for the purpose of ad valorem taxation also identifies high value areas for mining investment. The methodology is unique in that it accounts for most mining, environmental, and market factors to determine when specific properties are to be mined. The methodology and data base are useful for directing regional exploration and acquisition activities toward most favorable areas.

Jan 1, 1999