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By J de Cuyper, N. R. Tipman, G. E. Agar, L. Laré, W. Freyberger

The flotation chemistry of the commercial INCO matte separation process was investigated. The slow cooling of Bessemer converter matte forms discrete phases of Cu2S and Ni3S2 and a Cu-Ni alloy. After magnetically removing the alloy, the Cu2S and Ni3S2 are separated by flotation at pH 12.4 (saturated lime) using diphenyl guanidine (DPG) as both collector and frother. DPG has been used exclusively in this flotation process because of its unusual selectivity for copper minerals. The surface product resulting from chemisorption of DPG onto the Cu2S was identified as the double salt Cu(DPG)2SO4,.CU(DPG)2(OH)2. The adsorption followed Langmuir behaviour up to a monolayer coverage. In the absence of DPG, the rapid adsorption of oxygen by Cu2S in flotation pulps was observed. The surface product was identified as the insoluble basic copper sulfate CuSO4.3Cu(OH)2 with the production of sulfate ion. In the presence of DPG, the oxidation reaction appears to be suppressed. The frothing properties of DPG and commercial frothers were compared. DPG is not a powerful frother. Batch flotation tests confirmed that DPG is a highly selective collector when compared to most sulfhydryl collectors.

Jan 1, 1976

By R. O. Y. Breese

Perlite is a hydrated acid volcanic glass that has been derived from the alteration of obsidians through incorporation of water into the silica structure. It is distinguished from other members of the water-bearing natural glass family by total water content, characteristic fracture and luster. The distribution of major occurrences worldwide is associated with silicic Tertiary through early-mid Quaternary volcanics related to plate movement. The No Agua dome and flow complex is one of the most highly studied perlite occurrences in the world. It clearly exhibits lithologic and textural zonations that reflect simple cooling history. Similar features are commonly observed within other perlitized, extrusive glass selvages. This paper briefly discusses current thought regarding geologic occurrence, the hydration process and the modes of origin with special emphasis on No Agua.

Jan 1, 1985

By George S. Austin

Perlite is rhyolitic glass with 2 to 5 percent by weight (wt.%) bound water held within the silicic-glass structure. It is often distinguished by vitreous, pearly luster and concentric perlitic fractures ("onionskin"). Occurrences worldwide are associated with Tertiary to middle Quaternary volcanic rocks. Perlite is in silicic domes, plugs, laccoliths, flows, vitric tephra, chill margins of dikes and sills, and welded ash-flow tuffs. It is a hydrated volcanic glass formed through secondary alteration of obsidian by the incorporation of water into the glass/silica structure. Post-emplacement hydration (weathering) of cooled glasses by meteoric water is the principal alteration process, but some hydration by magmatic or meteoric water during or shortly after emplacement, or hydration by water exsolved during cooling may occur. Commercial "perlite" is any volcanic glass that expands or "pops" when heated quickly to plasticity while evolving steam and thus forming a lightweight, frothy material. The expansion temperature typically ranges from 1,100 to 1,500°F. An expanded volume increase of 10 to 40 times the original volume yields expanded densities of 1.5 to 11 pounds per cubic foot (lbs/ft3). Perlite is mined by eight companies at 10 operations in six western states. New Mexico accounts for more than 80% of the total tonnage mined. The rest comes from Arizona, California, Colorado, Idaho, and Nevada. In 1992, domestic production was 571,000 short tons (st), domestic apparent consumption was 591,000 st, and the value of crude perlite was $15.3 million. In 1991, with about the same production and price of crude perlite, the gross value for expanded perlite was $101.7 million. Perlite exports in 1992, primarily to Canada, are estimated an 30,000 st; and imports, from Greece, are an estimated 50,000 st. In 1992, 70 plants in 33 states expanded crude perlite. Construction uses of expanded perlite accounted for 66% of total domestic sales. Expanded perlite used as filter aid accounted for 15%. All other markets, including use as a filler and in agriculture, accounted for 19%. Leading states for expanding perlite, ranked by order of sales, were Mississippi, Pennsylvania, California, Illinois, and Georgia. Domestic perlite encounters transportation disadvantages in some areas of the eastern United States compared to perlite imported from Greece. However, western U.S. perlite exports to Canada offset this in large part, and net import reliance for perlite is about 3% of domestic consumption. Perlite grab samples were tested at the New Mexico Bureau of Mines and Minerals Resources (NMBMMR) for their basic suitability in horticulture, construction, filter aids, and fillers/extenders using Perlite Institute techniques modified by the NMBMMR. Most commercial perlite ranged from 2.5 to 3.0 wt.% bound water for all major types (classical, granular, and pumiceous). Expanded density varied widely, but the lowest density of 1.9 lbs/ft3 was for granular. Average brightness of expanded perlite was 47.6 to 69.3%. Nonexpansibles, commonly obsidian or "dead" perlite, ranged from 18 wt.% to less than 1 wt.%, with granular perlte generally the lowest. Compacted density was not related to either perlite type or nonexpansibles present. Sieve analyses of the -50+100 mesh product showed that, in general, pumiceous perlite produces more fines and classical and granular perlite average 60 to 80% -30+100 mesh after expansion. Samples were tested for crystalline silica that ranged from below the detection limit of 0.5 wt.% to nearly 0.2 wt.%, but most tested below 0.5 wt.%. Although quartz content can be lowered in the expanded product by the expansion process, producers can further lower crystalline silica in the product by mixing low-quartz crude with high-quartz perlite before expansion. Chemical analysis by x-ray fluorescence confirms the rhyolitic composition of perlite, but indicates that surface weathering may increase the concentration of some elements, such as potassium and calcium, by infilling cracks or fissures developed during or after perlite emplacement.

Jan 1, 1995

By B. Denby, D. J. McMlarnon

During the ongoing research into the possible applications of Virtual Reality in underground operations, the AIMS Research Unit has developed a user-interface driven program which enables a user to input the geometry of underground mines, and add equipment and working processes in order to produce an accurate simulation of their operation. This paper describes the main features of this system (VR-MINE). Virtual Reality is a field which has grown out of three dimensional computer graphics techniques, and allows a user to move freely around a model held within the computer's memory. Movement around this model is carried out by the use of intuitive peripherals such as joysticks, with the user's view from their position within the model being produced in real time on a computer monitor or other device (such as a headset). This enables a user to interact with any three dimensional model and see the results of their actions immediately. VR-MINE is broken into two separate programs, both running under Microsoft Windows 3.1 or above. The first, the editor, allows the user to develop the mine layout and add equipment and personnel. The mine geometry is considered to be made up of various types of objects, for example a straight roadway segment which can be inclined, a junction roadway segment, and a turning segment. The geometry can then saved into a file to be loaded in by the second program of VR-MINE, the viewer. This generates a real- istic representation of the mine, with undulating floors and walls. It also has the ability to display multiple windows on the mine at the same time, which are arranged interactively. The simulation occurs within this program, with the user traversing the model in real time to examine possible areas of improvement in operations. This paper gives a number of examples of how the AIMS Re- search Unit has applied this technology to a range of underground mining scenarios to improve the safety of workers in the under- ground environment. The application discussed include computer graphics and Virtual Reality systems to training, risk analysis, visualisation, simulation, accident investigation and major hazard planning.

Jan 1, 1996

In late November 2010, a Laotian landmark was achieved for the country?s first tunnel boring machine - (TBM) driven tunnel. Italian contractor CMC di Ravenna celebrated the breakthrough of a 7.6-m- (25.1-ft-) diameter Robbins single shield TBM for a hydroelectric tunnel on the Nam Theun River. The Theun Hinboun expansion project and 5.5 km (3.4 miles) headrace tunnel will bring much needed power in-creases to Laos and Thailand. . ?Since this is the country?s first machine, it has awakened people?s curiosity and interest. We had experienced Italian and Chinese crew members, but we also trained many Lao workers during the course of the project, as this was something they had not seen before,? said Luca Barbàra, Far East Manager for CMC di Ravenna. The machine broke through on Nov. 21 into an exit shaft close to the intake structure on the river. The machine is now being disassembled and removed - CMC hopes to use it on upcoming projects in the region. Due to the current rainy season and relative low level of the tunnel, the last 100 m (330 ft) up to the intake structure will be completed using drill-and-blast after the waters recede below the tunnel invert.

Jan 1, 2011

By Gunnar Nord

Shifting ground conditions when tunnelling often call for different methods of attacking the tunnel face. In order to overcome problems with local unstable soft ground in a hard rock tunnelling project the Boodex method offers a cost effective alternative. Boodex and variants of it is a combination of two well-known techniques, drilling with Boomer rig using Odex gear. It will give a steel lined hole ready for grouting and the steel pipe has a load bearing capacity that means that a spiling effect is achieved. In this paper the method and some applications will be described with possibilities and limitations.

Jan 1, 2003

By R. V. Ramani

Control is a vital management function by which operations are brought into compliance with predetermined standards to achieve the goals of an enterprise. Events that are characterized by a low degree of expectation, avoidability, and intent necessarily have a low degree of control. Such events are difficult not only to predict but to control as well. Fortunately, very few industrial situations fall into that category of events. It is an axiom of control technology that in order to control, one must first measure; further to measure, one must know the characteristics of the subject (or environment) upon which the measurement must be made. Finally, if measurements are to be made reliably, the influences that affect the measurement must be known and, if possible, understood. The complete control cycle therefore consists of the following: (1) defining the objective, (2) planning to achieve the objective, (3) putting the plan into practice with appropriate instructions, (4) measuring variables or parameters of interest, (5) transmitting and transforming the measurements to analyze the system's status and to predict the future outcome, (6) comparing these with the defined objective, and (7) determining and taking corrective actions to bring the actual results closer to the objective. The management principle underlying the control cycle is the principle of management by exception. The application of the principle and the frequency with which corrective actions are taken vary according to the purposes of the review and control. For example, the control of a machine operation (e.g., truck on a haul road) may require adjustments and therefore data, analysis, and decisions, in intervals of seconds whereas the review for ore-grade control may take several hours. Reviews, on the other hand, for cost control may be done in intervals of weeks or months. In any case, three specific purposes of the control cycle are: (1) to correct the operation so that it follows the accepted plan closely, (2) to evaluate the operation and predict future outcomes in light of changes in the environment or of more experience, and (3) to review the objectives and modify these to be reasonable and realistic.

Jan 1, 1979

By C. P. Mangelsdorf, Richard A. Allwes

At the request of the U.S. Department of Labor, Mine Safety and Health Administration (MSHA), the U.S. Bureau of Mines evaluated the suitability of using tri-sets for protecting mine personnel in roof-fall prone areas. A steel-set arch provided by MSHA served as a basis for evaluating the performance of the tri- set. All tests and analyses were conducted according to the arch canopy test and design procedures developed by the Bureau. Theoretical resistance functions were established for the steel-set arch and tri-set and were representative of their experimental behavior. The resistance functions were used to determine the energy absorption capacity of the structures and to predict their dynamic response to impact loading. The dynamic tests demonstrated that the arch canopy design procedure is appropriate for tri -sets and yields conservative designs for both steel-set arches and tri-sets. As a result of this work, it is recommended that tri-sets may be considered for protection against roof falls, provided that the arch canopy design procedure is utilized for each application and that the principles underlying the design procedure are understood.

Jan 1, 1992

By Bern Klein, Richard W. Lawrence, Scott Frostad

Laboratory and field scale kinetic testing was conducted to evaluate scaling up of laboratory data. Two 20- tonne (field) cells were monitored for internal temperature, pH, conductivity, volume and rate of flow, and water quality. On a surface are. basis, results showed sulfide oxidation rates obtained using 50-kg cells are more sensitive to changes in aeration than those from 1-kg cells. Correcting the laboratory oxidation rates for field temperatures with a pH 7 activation energy, which is in the field drainage pH range, returned oxidation rates an order of magnitude lower than the field cell rates.

Jan 1, 2000

By C. S. Thompson, P. A. Ciullo

Pyrophyllite is a naturally occurring hydrous aluminum silicate with the molecular formula SiO,,AI,,(OH), or, as more commonly expressed, the oxide formula A120,~4Si02~H20. Pyrophyllite is rarely found in deposits as the pure mineral and is often intimately associated with quartz, sericite, kaolinite, and diaspore. These associated minerals, to a large degree, help determine the most appropriate commercial application for a given pyrophyllite ore. Structural similarities plus the generally soft platy nature of pyrophyllite has in the past caused it to be included with talc in applications and production data. The Minerals Yearbook, published annually by the US Bureau of Mines (USBM), still reports on talc and pyrophyllite together, although admitting that they do not share the same uses. Pyrophyllite has also at times been considered a clay mineral because of its structure and chemistry. The refractory properties of pyrophyllite have been known for nearly 200 years, but it has only been in the past 60 to 70 years that a variety of applications have been developed to exploit the unique characteristics of this mineral. Worldwide, pyrophyllite is a component of refractories, whiteware, foundry mold dressings, pesticides, paint, plastics, rubber, cement, fiberglass, and soap. Historical Overview The most salient refractory features of pyrophyllite are its low coefficient of thermal expansion, high thermal conductivity, low moisture expansion, and good resistance to corrosion by molten metals and basic slags. One of the first recorded uses of this mineral was as firebrick in Japan in the early 1800s. This followed its discovery in 1797 on Mount Omotoyama at the site of the present Mitsuishi mine. In addition to firebrick, sawn blocks of ore were used for carvings and in the manufacture of slate pencils and signature seals. The Mitsuishi mine is still one of Japan's largest. By the mid-1800s, refractories were being made in Japan from roseki (a pyrophyllite-bearing ore) for the construction of metal melting furnaces. The mineral did not get its name until 1829 when R. Herman, testing a sample of supposed talc from the gold-quartz veins at the Berezovo deposit in the Urals, showed that it was actually an aluminum silicate and designated it pyrophyllite. This name was derived from the Greek pur for fue and phullon for leaf, in allusion to the effect of heat in causing separation of the laminae in foliated varieties (Mellor, 1927). The exact date of the discovery of pyrophyllite in the United States is uncertain, but it is believed that the talc and soapstone deposits noted in an 1827 report on the geology of the slate belt of North Carolina were actually pyrophyllite occurrences (Olmstead, 1827). Pyrophyllite was first used in North Carolina on a local basis in the early 1800s. Blocks were sawn and cut for use as stove linings, mantels, chimneys, fireplaces, and gravestones. This was the material of choice because it did not shrink when heated, but cut easily and hardened as it weathered. Pyrophyllite crayons were sold commercially by local gold miners for steel marking and as tailor's chalk from about 1800 until 1922. It was during this period that pyrophyllite was discovered near the town of Hemp (later renamed Robbins), NC. The large quantity of scrap resulting from the sawing of crayons at this deposit prompted the construction in 1921 of a grinding plant. The ore scrap was ground to fine granules and sold to asphalt producers to prevent shingles from sticking together. By the mid-1930s, milled pyrophyllite from North Carolina was also being successfully utilized by the ceramics industry in whiteware for its low cost and ability to shorten firing time. Also during the 1930s, pyrophyllite was first used in kilncar furniture in the United States. Canada was another early entrant in the pyrophyllite business. Mining at the Foxtrap deposit on the Avalon Peninsula of Newfoundland began in 1904, with ore shipped to the United States. Production from this deposit was mostly sporadic in the ensuing years until 1956 when mining began for shipment and captive use in US tile manufacture. This production has remained continuous and still essentially captive to the present. The Foxtrap deposit is currently the sole commercial source of pyrophyllite in Canada.

Jan 1, 1994

By Dipl. -Ing. H. -J. Sager

The ‘Westerschelde Tunnel’ underpasses the estuary of the Schelde in the Netherlands. The tunnel will consist of two tubes which are driven by two hydroshields (slurry shields). The tunnels will each have a length of approx. 6.6km and a bore-diameter of 11.33 m. Demanding ground conditions had to be considered during the design of the shield machines. Loose sands, extensive clay formations and high ground water pressures of up to 6.5 bar will be encountered during the tunnel drive. The tunnelling activities will start in the middle of 1999 and are scheduled to end by the end of 2001.

Jan 1, 1999

By Phillip O. Tyree, R. A. Metz, Joseph W. Mussey

Bio-epigenetic sulphur deposits occur in Pecos, Reeves and Culberson counties of far West Texas. Sulfate reducing bacteria, utilizing hydrocarbons as energy, transformed gypsum into replacement limestone and hydrogen sulfide. Hydrogen sulfide, retained in the pores of the replacement limestone, was subsequently oxidized by highly oxygenated groundwaters, and native sulphur precipitated. West Texas sulphur was first recognized at surface exposures by William P. Blake, a geologist attached to the Captain Pope Military/ Scientific Expedition of 1854. Attempts were made in the early 1900's to mine these sulphur vent exposures by a retort method, but the ventures met with little success. In 1967, Duval discovered a large sulphur deposit near some of the old sulphur works in Culberson County. Duval also expanded reserves in a small sulphur deposit in Pecos County. The Frasch process, developed for producing sulphur from Gulf Coast salt domes, proved successful in West Texas type sulphur deposits also. However, modifications of the process were necessary to provide economical and efficient sulphur recovery from the varied ore occurrences. West Texas conditions and logistics require the ultimate in productivity to be competitive in the domestic and foreign sulphur markets. Several companies, in addition to Duval, are producing or have produced sulphur in West Texas. As of June 1, 1984, a total of 29.87 million mt (29.4 million long tons) of sulphur had been produced west of the Pecos River. Duval corporation has produced more than 88 percent of that total.

Jan 1, 1992

By Hans Smit

The face of mining as we know it is set to change in the very near future as mining companies all over the globe realize the implications of accessing the vast mineral wealth contained on, and under, our ocean floors. With some land based mineral deposits being fully exploited across the world, deep sea mining is set to revolutionize global approaches to the search for precious metals and other sought after minerals. [ ] Previously, the financial implications of deep sea mining outweighed the benefits of access to the mineral rich deposits identified all around the world. The process of marine diamond mining off the west coast of southern Africa started in the late 1950?s by a Texan, Sammy Collins, and subsequently continued by De Beers to the present day, has proven to be an excellent proving ground for the development of technology and mining systems that ensure a sustainable and financially viable business. [ ]

Jan 1, 2008

By H. M. Park

Risk is a major factor in all mining activities, arising from many internal and external variables. The authors? research has resulted in a systematic method for the quantification of risk in mining projects (Park, 2012). This research will be presented in a series of papers, this one and two more that will be published on Mining Engineering?s web site, www.me.smenet.com. This paper identifies the variables associated with risk in mining projects, and their effects. The second paper discusses methods of assessing the overall risk associated with those variables, and presents a statistical model based on a survey of 31 experts. The third paper presents an evaluation of the statistical model, using data from previous mining investment decisions in which the authors have been involved. There are several major competing entities, including BHP Billiton, Rio Tinto, Anglo American, Xstrata, Freeport-McMoRan, Chinese government- run companies and Japanese trading companies, that have large foreign holdings, controlling deposits in most of the world?s established and productive mining districts. In general, the mining industry considers the United States, Canada, Australia and the European countries to have good mining investment environments, but because the major companies have already achieved market dominance in those countries, large investments are required there. Newcomers seeking to enter the industry, either as producing companies or as investing partners, often have difficulty breaking into these established markets. Thus newcomers are increasingly turning to new areas like South America and Africa, which are relatively less developed. The competition among businesses to secure a share of the new market is intense, but there are still good investment opportunities. However, because most of the countries in these areas are not well developed, several additional risks are associated with participation in mining projects in those areas.

Oct 1, 2013

By R. E. Musgrove

At the present time Climax Uranium Company recovers vanadium oxide from carnotite type uranium ores in the mill at Grand Junction, Colorado, The flowsheet of this mill is shown in Figure I. Vanadium is solubilized by a salt roast of the slime fraction of the ore and dissolution is accomplished by a water leach. The metal is precipitated from the pregnant liquor as sodium polyvanadate by heating to boiling and adjusting the pH to 3 with sulfuric acid. The sodium polyvanadate, commonly called, "red caken, is filtered, melted, and cast into thin flakes. This fused flaked vanadium oxide is the material which is packaged for sale. Fused vanadium oxide, marketed by Climax, contains approximately 87% V205, 7% alkali oxide, 0.08% sulfur, 0.03% phosphorus, and less than 0.5% Insoluble. This material is of a lower grade and has a higher alkali oxide content than other vanadium products offered for sale at this time. A typical analysis of a high grade vanadium oxide currently offered for sale by another company is 98% V205, 1 - 2% alkali oxide, less than 0.05% sulfur and less than 0.2% Insoluble. The only reagent consumed in the precipitation of the sodium polyvanadate is sulphuric acid. The total reagent cost is 0.58 cents per pound of vanadium oxide produced.

Jan 1, 1958

By S. E. Phillipson, S. Romberger

The Late Miocene San Cristobal Ag-Zn-Pb deposit represents syngenetic and epigenetic mineralization with low- and high-sulfidation characteristics. The geology of the deposit is characterized by barren dacitic ring fracture domes, mineralized resurgent rhyodacite domes, strongly altered and mineralized tuffaceous lacustrine sedimentary rocks and an extensive crystal-lithic tuff debris apron. The orebody is hosted by intracauldron sedimentary rocks and breccias. Fluid inclusion data suggest that silver, lead and zinc were transported as chloride complexes and precipitated by cooling in veins from <5% (by weight) NaCl eq. fluids at 170° to 215°C. Silver spatially and perhaps temporally associated with resurgent rhyodacite was transported as a chloride complex and precipitated by increased H2S activity or increased fluid pH.

Jan 1, 2002

By Hans Svensson

INTRODUCTION The Alimak method of raising (Fig. 1) was intro¬duced in 1957. Because of its flexibility, economy, and speed, it soon became the most used system of raising in the world. With the same unit, raises of various areas, inclinations, and lengths can be driven. Air-motor¬-driven raise climbers normally are used in mines with short raises (Fig. 2). For longer raises electric or diesel-¬hydraulic drives are used. The Alimak raise climber is designed entirely in ac¬cordance with the instructions of the Swedish Board of Industrial Safety (Arbetarskyddsstyrelsen). There are good margins of safety concerning the breaking strength of the material and the raise climber comprises safety devices and features that practically eliminate the risks of accidents. The drive gear of air-driven climbers is equipped with an air-operated brake which is automatically activated when air for the motors is shut off. There is a safety device which activates automatically at overspeed and a speed-regulated brake for descent by gravity, by which the raise climber can be taken down to the bottom of the raise in case of cutoff of the air supply. The raise climber climbs along a pin rack welded to a guide rail which also comprises pipes for air and water. The guide. rail can be extended by using 1- or 2-m (3.2¬or 6.4-ft) sections as the driving progresses. Each guide rail section is bolted to the rock wall by special expan¬sion bolts of Alimak design. Men ride up to the face in the cage, traveling com¬fortably and easily while material is transported on the platform. There is no dangerous climbing up ladders. The men are well protected during ascent and arrive in good condition at the face. The greatest advantages of raise climber systems are flexibility and versatility. The equipment provides a comfortable working position in vertical as well as in¬clined raises of any area and length. The direction may

Jan 1, 1982

By A. E. Isaacson

Researchers at the Bureau of Mines, U.S. Department of the Interior, developed and tested equipment to measure corrosion rates on a commercial-scale mill. Bench-scale experiments were also designed for duplicating ore grinding conditions closely enough that realistic rate determinations can be made in laboratory tests. Rates measured in a laboratory system compared favorably with those measured in the field. Cast steel was found to have corrosion rates in a copper mill and laboratory test cell of 22 and 21 mpy, respectively. Corrosion was found to account for less than 5 pct of the total grinding media wear in the operations studied.

Jan 1, 1989

By Don Phelps, Christopher Tattersall, David McAllister

Located south of downtown Seattle, the Beacon Hill Station & Tunnels is the key section of the southern segment of Sound Transit’s proposed new LINK light rail system. This paper presents an overview of the design, which includes 4,300 ft of segmentally-lined bore twin tunnels and a deep mined station. With platforms located156 feet below grade, the station itself is only the second large-scale mined station in soil the US. Its complex geometry combined with variable soil conditions—sands, silt sand clays with slickensides—challenged the designer’s to come up with a SEM-based design that addresses the owner’s risk, cost and schedule concerns.

Jan 1, 2003

By Robert C. Cifelli

INTRODUCTION Background and Objectives Underground coal mining is a vital component of West Virginia&apos;s economy. However adverse environmental effects including ground subsidence and aquifer dewatering are often associated with such mining activities. Many families in northern West Virginia still rely on private water wells and springs for domestic water needs. In such areas where underground coal extraction and land subsidence have occurred, a disruption of the ground water flow system commonly exists with subsequent drainage of water to lower levels that may extent as deep as the mine workings; this causes loss of water supplies to landowners and represents a nuisance to mining companies 2 This report represents a summary of an M. S. thesis project in geology at West Virginia University by the senior author (3). The intent for this study was to document the effects of underground coal removal on ground water levels at selected mine sites in northern West Virginia, as observed from water wells, springs, and streams. This research should be useful to coal companies and regulatory agencies and aid in recommendations of future water well locations and specifications in areas of existing or proposed underground coal mines.

Jan 1, 1986