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By G. France

The Blair Athol Coal Mine (BAC) is a large open cut operation in the Bowen Basin of Queensland, Australia. Current mine capacity is about 11 million tonnes per annum(Mtpa) of export coal. On-line analysis at BAC consists of two Coalscan 9500s installed directly on the output of the crusher plant and immediately before the product stockpiles, while a third Coalscan 9500 is installed on the transfer conveyor feeding the train loading bin. The two product Coalscans have a dual purpose. The first is to provide real time coal quality data directly back to the mining operations. The second is that of modeling the product stockpile with accurate on-line information. This modeling enables both production and coal quality personnel to accurately examine the coal quality of each stockpile with a degree of resolution which previously had never been achieved.

Jan 1, 1999

By D. F. Scott

Spokane Research Center personnel have been investigating the use of seismic tomography to monitor the behavior of a rock mass, detect hazardous ground conditions, and assess the mechanical integrity of a rock mass affected by mining. Seismic tomography can be a valuable tool for determining relative stress in deep (> 1220 m) underground pillars. If high-stress areas are detected, they can be destressed prior to development or avoided. High-stress areas can be monitored with successive seismic surveys to determine if stress decreases to a level where development can be initiated safely. There are several benefits to using seismic tomography to identify high stress in deep underground pillars. The technique is reliable, cost-effective, efficient, and non-invasive. Also, investigators can monitor large rock masses, as well as monitor pillars during the mining cycle. By identifying areas of high stress, engineers will be able to assure that miners are working in a safer environment.

Jan 1, 1997

By Louis P. Gignac

The Lac Shortt gold deposit is located in Northwestern Quebec, at some 115 km west of the Opemiska Division and 380 km northeast of the Lac Dufault Division, as shown on Figure 1. Falconbridge's exploration crews drilled the first six holes in the gold-bearing ore zone in 1979. After further diamond drilling from surface in 1980, the decision was taken to carry out an underground exploration program. A three-compartment shaft was sunk to a depth of 340 metres in 1981 and 1982; it was followed by an extensive exploration program, which included 1073 metres of cross-cutting and footwall drifting, 645 metres of ore drifting and 11 200 metres of diamond drilling. The underground work was completed by mid-winter 1983. It was followed by a complete feasibility study of the Lac Shortt Project. After some $Can 14.2 millions in exploration expenditures, the Board of Directors of Corp. Falconbridge Copper approved in July 1983 additional expenditures of $Can 45 millions to bring the Lac Shortt Mine in production at the capacity of 261 000 tonnes per year. Gold price was $US 425 per ounce at the time.

Jan 1, 1985

By Joseph W. Mullan

The today status of air pollution control legislation and regulations can best be described as an exaggerated state of environmental limbo. The '70's began but one and one-half months ago yet it already has been very appropriately named "the decade of the environment." This certainly will be the decade for new legislation - new regulations and hopefully "Clean Air." Already Washington is faced with legislators playing "pollution politics" to the crowds. Students have redirected their efforts from Vietnam to the cleansing of the environment and everyone including the man on the street has become an environ¬mental expert. This is the decade we all face, but where are we today? Pollution is not a new problem. It has been with us for centuries and while much is left to be done, much has already been accomplished. I will try to make some comparisons of what I believe to be the good and bad points in the national air pollution control picture and hopefully will generate within each of you sufficient concern as to which comparisons are sound.

Jan 1, 1970

By A. I. Johnson

This paper describes," the application, of a modular or building block approach to the analysis, design, and control of complex mineral treating processes. The main purpose of the paper is tutorial, to show the reader how such processes can be modeled using a modern digital computer" and, not to discuss in any detail the results that may be achieved in such studies. It is proposed that, the main techniques be illustrated by reference mainly to the Bayer process for alumina extraction and purification; in cooperation with the Aluminum Company of Canada Ltd. the author and his Colleagues at McMaster University and their students have studied this, process as a means of applying new computer techniques to extractive metallurgical processes. The plant described was studied by the author and his colleagues as a senior undergraduate project in cooperation with the Aluminum Company of Canada. It is one of several studies that have been carried out with Canadian industry. (1)

Jan 1, 1972

By Roger K. McLimans

Sphalerite in the ores is multi-banded. Based on color and textures, bands in samples separated by a few kilometers may be correlated. Darkness of color is directly related to iron content. Isotopic and fluid inclusion data indicate that temperatures of ore deposition were 225°C-50°C. The agreement between these two sets of data suggests that chemical and isotopic equilibrium were established. The salt content and hydrogen and oxygen isotopic compositions are similar to present-day values of oil field brines suggesting a similar mode of origin. Ore transport and deposition are not adequately explained by either chloride or bisulfide complexing. Necessarily, other mechanisms were involved.

Jan 1, 1979

By Howard G. Coopersmith

Kelsey Lake kimberlites are a cluster of eight diamondiferous pipes that occur in the northern State Line kimber lite district of the Colorado-Wyo¬ming diamond province (Coopersmith 1991, 1993) (Fig. 1). This is located at the southern margin of the Wyoming Archean province. Two relatively large pipes and a few smaller bodies define the cluster (Fig. 2). The Kelsey Lake kimberlite cluster has been developed as the first diamond mine in the United States. The cluster was discovered in 1987. Full-scale production began in the spring of 1996. Mining has produced gem-quality diamonds up to 28.3 carats in size. The 30 State Line kimberlites, intruded about 390 million years ago into Proterozoic crystalline rocks, were presumed to be underlain by Archean basement of the Wyoming Province. Nearly all the kimberlite pipes contain diamond but only the Kelsey Lake pipes are economic. The Kelsey Lake kimberlites contain predominately diatreme facies kimberlite, with minor hypabyssal and crater facies rocks locally occurring. Alteration and weathering of the kimberlites is extensive. Petrologic studies indicated an underlying lithosphere that has a largely Proterozoic signature and shows evidence of deep melt and metasomatic events. Current development has concentrated on the two largest pipes. These have been bulk-sampled after geological study (1987) identified the presence of small diamonds and mineral chemistry indicating favorable diamond conditions. A 10-t/hr (11-stph) rotary pan plant was established in 1992 to process thousands of tons of bulk-sample material. Grades and gem-quality diamonds to 14.2 carats in size were recovered. Early in 1995, it was decided to move from evaluation to commercial mining. Production began in early 1996. A 195-t/hr (215-stph) rotary pan plant was built. A water supply system and tailings disposal have also been incorporated. The project straddles the Colorado/Wyoming border. Existing mining permits were amended to incorporate the increased scale and new plant facility. The permits for this project included the following: Colorado mining permit, Wyoming dozing permit, Corps of Engineers Section 404, Colorado NPDES, Wyoming NPDES, Storm water Management Plan, Air Pollution Emission Notice, various Colorado and Wyoming State Engineer and well permits, Substitute Water Sup¬ply Plan, Larimer County Special Use Review, and US Forest Service road use permits. The temporary destruction of a wetlands area was a sensitive issue. It has been addressed through the Clean Water Act Section 404 permit administered by the US Corps of Engineers. This use will be mitigated by creating new, self-sustaining wetlands in the immediate drainage system. A comprehensive and bonded reclamation plan is incorporated in the permits. Diamond mining and ore processing is environmentally benign. No chemicals are used in processing the diamonds. The plant is a water wash facility. The kimberlite ore is inert, as is the granite wall rock. The exposure of the ore body and the subsequent ore processing and waste rock and tailings containments pose no threat of release, leaching or dispersion of any detrimental elements. There is no acid-forming waste. Even a prolonged acid rain environment will not produce a harmful leachate. Slimes containment and clarification ponds will prevent unacceptable levels of suspended solids in water discharge. The isolated, restricted access and nonvisible nature of the mine and processing has led to straightforward permitting. Geology The State Line district is located in the northern

Jan 1, 1997

By William H. Dresher

The crust of the earth, together with its seas and its atmosphere, is the source of all of mankind's primary wealth. Indeed, most people think of precious metals and stones when they think of wealth mined from the earth, but the value of the material and energy goods derived from the earth far exceed the value of the precious metals and gem stones. Thus, it is obvious that all minerals which we mine from the ground represent new wealth--the copper, clay, or petroleum we mine just as much as the gold or silver. More and more, wealth is defined in terms of utility-not in terms of an arbitrarily established monetary value. The recent action of the OPEC nations in controlling the flow of petroleum has clearly demonstrated this to the petroleum-importing nations! There is developing in the United States, as well as in many other nations of the world, a concern for the future availability of many mineral-derived raw materials and of mineral fuels. Ore grades are diminishing, concern for the environment has placed restraints on commercial development of some mineral deposits and the processing facilities necessary to exploit them, and countries upon which we have relied for major mineral materials have become increasingly nationalistic, causing uncertainties in future supply and causing an increasingly alarming deficit in our nation's balance in trade.

Jan 1, 1980

By F. T. Paleari

Radial gas holdup profiles have been measured in a 50x400 cm flotation column using a multi-cell conductivity probe. Three different bubble generation systems were examined: up to eight vertical filter cloth spargers, three horizontal filter cloth spargers, and three (horizontal) Cominco-type spargers. The variables tested were: number of spargers, symmetry of their arrangement, and height above spargers. Batch water with up to 20ppm frother concentration was used. The general observation is that the profiles tend to be uniform (i.e. flat) with some exhibiting a slight wavy shape. The vertical sparger arrangement proved the most difficult to achieve profile symmetry. The horizontal spargers gave uniform profiles at right angle to their length but a decreasing gas holdup along their length; the Cominco-type spargers gave slightly less scatter in the data. Switching off selected spargers (to simulate malfunction) did not produce strong asymmetry in the profiles.

Jan 1, 1993

By B. K. Parekh

The International Symposium on Comminution was organized at Camborne School of Mines, Cornwall England. Papers covered the fundamental and practical aspects of comminution in the mineral industry. Although comminution equipment design has not changed fundamentally during the last 50 years, methods of control and optimization have improved considerably. A simulation model for batch ball milling in the rotating mill was developed as a step toward continuous simulation of ball and autogenous milling. New concepts in jaw crusher technology design and the concept of a 1.6- x 2.1-m (66- x 84- in) jaw crusher with open feed throat has resulted in power savings. The use of cone crusher technology in comminution circuits with particular reference to machine design, plant flowsheet and control figuration has been reported by Boliden Allis, of Sweden. The Whiten steady state crusher model form has been used to develop a quantitative model of 2.1-m (7-ft) cone crushers. This was done by incorporating liner age (wear) and liner length as variables on the selection of particles for breakage and thus on the product size distribution. Another paper by Lira and Karetsky discussed the development of a model based on a multisegment ball mill developed by Whiten and Kavetsky. It is capable of simulating the performance of a coarse grinding ball mill of a given diameter, ball size and mill speed.

Jan 1, 1991

By D. Van Orden, Y. Kamiya, R. Lee, E. Ilgren

Crocidolite is a well-known causative agent for mesothelioma. However, studies have shown that the pathogenicity of the fiber from different mines varies considerably and it has been postulated the parameter that appears most likely to account for this variation is fiber width although this has never been formally confirmed. To date, crocidolite appears to be the only asbestos mineral for which an epidemiological study comparing the risk of mesothelioma in a population exposed to ‘thin’ fibers with another exposed to ‘thick’ fibers of the same species may be carried out. Finnish anthophyllite, South African amosite, and African Transvaal crocidolite can also be classified as thick fibers, and there is a paucity of mesotheliomas in populations exposed to them compared to those exposed to thin Cape crocidolite. No thin occurrences of these minerals are known. Our previous study looked at crocidolite from several sources. The present study considers the amphibole anthophyllite found in many places in the world. This mineral, regardless of source, does not show the same variation in fiber width found with crocidolite from different areas. All anthophyllite fibers that have been mined may be classified as thick and populations exposed show very low levels of mesothelioma. We suggest the most likely explanation is related to the fiber width distribution and a concomitant reduction in the ‘Stanton fiber size’ fraction.

Jan 1, 2012

By Karl A. Olsson

The Glenharold Mine is a surface mine operated by Consolidation Coal Company. The mine is located approximately 90 kilometers (55 miles) northwest of Bismarck, and 3 kilometers (2 miles) southeast of Stanton in west central North Dakota. Glenharold has a nominal design capacity of 3.0 million metric tons per year (3.3 million short tons per year). With the exception of local coal sales, this production supplies fuel for Basin Electric's Leland Olds generating station, a mine mouth power plant. The mine has 175 hourly and 50 salary employees. The Glenharold reserve extends over 210 square kilometers (80 square miles). The mining area is on a dissected plateau between the broad flat Missouri River flood plain to the north and the gently rolling uplands to the south. Erosion by intermittently flowing streams has produced many narrow, steep-walled, drainage ways. Mining begins at the 6 meter (20 foot) cover line and continues to the economic recovery line.

Jan 1, 1982

By Andy Davis

The evolution of pit lake water quality depends on the lithology and hydrologic characteristics of the ultimate pit surface, the availability of buffering capacity in the wall rock vs. oxidizable sulfide content, the alkalinity of recharging groundwater and the evapoconcentrative characteristics of the system. This paper assesses the geochemistry of 11 existing pit lakes, ranging from the acid Red Hill and Berkeley pit lakes (pH 2.6 to 2.8) to the alkaline Yerington pit lake (pH 8.45). Predicted pit lake chemistry is similar to that in existing pits, with long-term chemistry lying on a geochemical continuum between end members that consist of influent calcium bicarbonate groundwater and naturally occurring sulfate-rich evaporate playa lakes.

Jan 1, 1997

By C. R. Copeland

Water sprays are a common method used to reduce particulate matter (PM) emissions. Various factors such as wettability, surface area coverage, fine particle engulfment rates, interparticle adhesion forces, suppressant penetration and suppressant longevity have all been suggested as critical factors in achieving effective PM control. However, it has not been established which of these factors are the most important. Experimental work indicated that suppressant penetration is the most critical of these factors. The length of time after application that suppressants were effective was also improved by using hygroscopic reagents that retained moisture to prevent evaporation. Maximizing suppressant penetration and improving suppressant longevity led to an average 86% reduction in PM10 concentrations in laboratory dust tower tests.

Jan 1, 2008

Gangue-cemented paste backfill (GCPB), is a well-established green mining technology and significantly improves the recovery rate of mineral resources, prevents mine dynamic disasters, reduces surface subsidence, and consumes a considerable amount of solid waste. The addition of an early strength agent as an additive in cement-based materials provides several security, technical, and economic advantages. In this study, the early strength agent on the early age (3, 7 and 28 days) strength of GCPB is evaluated experimentally. The GCPB specimens have an initial sodium sulfate early strength agent concentration of 0%, 1%, 2%, 3%, and 4%, and the obtained samples were analyzed by testing for uniaxial compressive strength (UCS) and scanning electron microscopy (SEM). The test results show that the UCS of the GCPB specimens with sodium sulfate is much higher than that of the blank specimens. When cured for 3 days and 7 days, the strength of GCPB with 2% sodium sulfate increased the most, by 131% and 116% respectively. When cured for 28 days, the strength of GCPB with 1% sodium sulfate increased by 135%. Scanning electron microscopy (SEM) results showed that the GCPB with 1% and 2% sodium sulfate had better internal structure compactness, thicker acicular crystals, and more flocs. As a kind of early strength agent, sodium sulfate can react with calcium hydroxide to generate calcium dihydrate sulfate and then react with calcium aluminate; the hydration product (C3A) quickly generates calcium sulfoaluminate hydrate (AFt) needle-shaped crystals, forming an early skeleton and improving the early strength.

Jan 7, 2020

By T. G. Legare

It is now well documented that trace amounts of silver, gold, and platinum group metals occur in certain geothermal brine deposits. A significant body of literature has been generated over the last twenty years which describes attempts to quantify the frequency and levels of these precious metals in the brines. This literature is often confusing and contradictory. For example Barnea 1 states that the Salton Sea geothermal field carries 2 ppm gold, yet more recent data by workers at Lawrence Livermore National Laboratory2 (LLNL) concludes that the gold level in Salton Sea brine is <0.07 ppb. They report a platinum level in one well of 55 ppb. This apparent contradiction may be explained by sampling source and technique, but is most probably explained by difference in analytical technique. Analytical techniques and problems will be discussed in the next section.

Jan 1, 1985

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept. 11, 2010 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. The 23rd Annual National Mining Hall of Fame and Museum Banquet will begin with an open house and reception at 5:30 p.m., followed by the dinner and program at 7 p.m. The four inductees are: William Wheeler Coleman who served 46 years, from 1911 to 1957, as president and chairman of the company that is now Bucyrus International of South Milwaukee, WI, a world leader in the manufacture of surface and underground mining equipment. Dr. Allen Van Heyl, Jr., an economic geologist who served with the U.S. Geological Survey for nearly 50 years beginning in 1943. He studied more of the nation?s mineral deposits than most could begin to imagine. Arthur Lakes contributed enormously to the geological and mining sciences in the western United States as a geologist, teacher, writer and artist over a period of more than four decades beginning in 1869. The Arthur Lakes Library at the Colorado School of Mines, Golden, CO, is named for him. Samuel Calvin McLanahan, through his inventive genius, changed the direction of his family?s company from that of a foundry to a leading manufacturer of minerals processing equipment to become today?s McLanahan

Jul 1, 2010

By Yi Luo, Jian Yang, Hua Jiang

Surface subsidence induced by underground coal mining activities, especially longwall mining operations, can cause various problems to interstate highways ranging from structural integrity, drivability to safety. Accurate subsidence prediction, correct influence assessments, and effective mitigation measures are the keys to ensure the safety of highway traffic. The surface subsidence prediction program, called comprehensive and integrated subsidence prediction model (CISPM), was developed based on the principle of influence function method and has been validated with a large number of subsidence measurements. In this paper, the techniques to use the predicted final surface movements and deformations for assessing their influence on the integrity and functionality of highway structures (e.g., road surface pavements, concrete slabs, transverse joints, etc.), vehicle dynamics, comfort level, and drivability are presented. A number of mitigation measures to protect the highway structures and to ensure traffic safety are proposed along with an application case.

By L. Tondo, W. Lim

The high pressure grinding rolls (HPGR) is a relatively new technology which offers the potential benefits in energy savings, circuit simplicity and improved product characteristics in minerals processing applications. Over 300 machines are now operating world-wide, but most of these are used for grinding cement clinker, and relatively few are used in conventional mineral processing. One of the rea- sons for its current limited use in the minerals processing industry is that design, scale-up and flowsheet assessment procedures are seen to be relatively immature and untested. This has reduced confidence in the potential application of the technology. To help rectify this situation an industry funded research project was undertaken, one of whose aims was to develop and prove a mathematical model of the HPGR and a scale-up procedure. Data were collected from tests using laboratory, pilot and in one case a full scale unit (2.2m diameter). A range of feed types were tested including quartz, limestone, kimberlite, bauxite, iron ore and gold ore. These data were then used to develop models of the size reduction performance, power draw, throughput and operating gap for a wide range of pressures, feed sizes, and roll speeds. This paper describes the models that have been initially developed and illustrates their accuracy using some of these data.

Jan 1, 1998

By YU. F. Vasyuchkov, K. Vasioutchkov, B. M. Vorobjev

Introduction It is now believed that, even with the environmental protection measures now being taken, the further application of traditional coal-mining and electric power-generation technologies will inevitably cause further irreversible damage to the global ecosystem. Further improvements in conventional coal-mining technologies, both surface and underground, are expected to have only limited impacts on the economical, ecological and social aspects of coal mining. In countries with a developed coal industry, coal reserves with favorable conditions at shallow depths are rapidly being depleted. Therefore, in the future, more coal will be mined from deeper levels, resulting in higher operational costs and lower labor productivity. The solution to this problem is to be found in developing, promoting and implementing unconventional coal-mining and advanced clean-coal technologies. This paper presents an unconventional concept that has been suggested by the authors. The basic goal is to achieve coal-methane energy resource conservation and to remove barriers to energy efficiency through the adoption of integrated, ecologically clean, innovative technology. The following principles form the foundation of this concept: Energy resource conservation: This principle concerns the exploitation of actual and potential coal-methane reserves in the most effective way with the lowest possible losses and with the application of the most energy-efficient electric power-generation technology. Energy conversion: Energy conversion means the conversion of solid coal to synthetic fuel gas (in situ or in-cycle), the conversion of methane bounded within the coal matrix to free-flowing drained meth¬ane, the conversion of solid coal in situ to a coal/water mixture (slurry), and the conversion of these gas fuels into electric power. Technological and managerial integration: This prin¬ciple means an integration of coal-gas methane min¬ing operations and electric power generation into one commercial mine-to-product enterprise with electric power as the final product. Thus, coalbed methane drainage and coal gasification (both in situ and in-cycle) integrated with a combined cycle of electric power generation constitutes a highly integrated coal-gas methane energy-generation system. The system can be materialized in the form of a local integrated coal-gas electric power complex (LICGEPC). General features of the new concept The coal-gas-methane electricity concept is actually a synthesis of the following four technological components: Coalbed methane drainage. This technique and its utilization attained recognition after commercial operations were proven successful in the San Juan and Black Worriers coalfields in the United States. Worldwide, extensive field experiments and research-and-development activities are being carried out in the area of coalbed methane exploitation and utilization. Recently, coalbed methane drainage for power generation has been undergoing intensive research and development. At the Harworth Colliery in the United Kingdom, a combinedcycle power plant has been built that uses coalbed methane. The plant has an installed capacity of 15 MW Also, Germany, Australia, the CIS and China have conducted various experiments and industrial tests on the use of coalbed methane power generation. Underground coal gasification. Another unconventional technological approach is underground coal gasification (UCG). A number of semi-commercial, demonstration and pilot projects have been undertaken in Russia, the Ukraine, Uzbekistan, the United States, the United Kingdom, Italy and Belgium to demonstrate the technical and economical viability of coal gasification in situ. In Uzbekistan, the Angren coal-gasification station has been in full-scale commercial operation for two decades. The operation supplies a power plant with synthetic coal gas. Under sponsorship of the US Department of Energy&apos;s Morgantown Energy Technology Center, large-scale laboratory tests simulating coal gasification in situ were successfully completed by the

Jan 1, 1999