Search Documents

By M. J. Zdunczyk

Located approximately 50 miles northeast of Knoxville, Tennessee, Short Mountain Silica mines the Clinch Formation, an orthoquarzite, for silica sand. In 1980, a Knoxville resident and area contractor visualized mining Short Mountain for silica sand. Because APG Industries, the main market for the glass sand product, was only 48 kilometers from the site, many silica sand companies became interested in the property. In 1986, J.D. Nicewonder began to develop the site, and in May of 1988, APG Industries received the first sand shipment.

Jan 1, 1992

By M. E. Buzon, M. E. Gunter, B. D. McNamee

A Google search on talc asbestos yields more than 500,000 hits due to the growing number of civil lawsuits in this area. Historically, the litigation was centered on amphibole-containing industrial talc. There was no debate these talcs contained amphiboles, but the issue was the definition of asbestos and whether the amphiboles had an asbestiform habit. Ultramafic-hosted talcs, however, are formed in such a way as to not favor the formation of amphiboles in the talc, but they can occur in the surrounding black-wall. In these deposits, the serpentinite host rock is in direct contact with the talc, therefore, allegations can be made that non-asbestiform amphiboles or non-regulated serpentine group minerals can occur in the final products. We analyzed talcs from both metamorphosed carbonate- and ultramafic-hosted talc deposits using polarized light microscopy (PLM), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), electron microprobe (EPMA) with wavelengthdispersive spectroscopy (WDS), transmission electron microscopy (TEM) with EDS, and powder X-ray diffraction (XRD). Compositions of minerals determined by EDS alone are not sufficient to confidently identify asbestos, despite common practices by some researchers. We emphasize, using both historical samples, and analyses of currently contested minerals, the importance of determining both the structure and composition of a mineral, as well as defining its morphology, before concluding whether it is asbestos.

Jan 1, 2018

By Eddie Woods, Jon Hurt, Roger May, Paul Watson

The Channel Tunnel Rail Link (CTRL) will be Britain’s first major new railway for over a century—a high-speed line running for 109km (68 miles) between St. Pancras station in London and the Channel Tunnel. The new line has been under construction since October 1998 and the first phase will open in October 2003. The project includes22km of twin 7.15m ID TBM bored tunnels under London and the River Thames, and the 3km North Downs Tunnel, the first major NATM tunnel to be constructed in the United Kingdom since the collapse of the Heathrow Express Tunnels in 1994. This paper will discuss the design of these tunnels and describe the construction progress to date. The discussion will include details of segmental lining design, TBM specification, and sprayed concrete lining design.

Jan 1, 2003

By P. G. Kovalchik

Recent research conducted by NIOSH, Pittsburgh Research Laboratory showed that electrical current levels permitted under present regulations may not limit cable temperatures to less than 90°C in reeled trailing cables. Reeled cables, tightly wrapped with many turns, all carrying current in an enclosed space, can become overheated due to poor heat transfer. This overheating can cause the cable insulation to soften and become easily damaged. The damaged insulation reduces the life of the cable and can lead to shock, electrocution, and mine fires. This paper describes a method of measuring the conductor temperature of mine trailing cables during normal operation. The temperature is measured using a 50/125 micrometer Graded Index Multimode Optical Fiber located in the center of the metallic conductors. Distributed temperature measurements are made using an Optical Time Domain Reflectometer (OTDR). This system is capable of measuring temperature with an accuracy of plus or minus one degree centigrade over a length of 4 km at 1-m intervals. With this unique way of measuring temperature, tests can be conducted simulating actual mine conditions and provide important data to allow MSHA's Approval and Certification Center to develop approval criteria for cyclically rated reeled machines.

Jan 1, 1998

By R. D. Beard

Puerto Rico lies within the remnants of a deformed Cretaceous island arc system in the northeastern Caribbean. The Island can be divided into three broad geologic provinces: the Central Volcanic-Plutonic Province (Lower Cretaceous to middle Eocene), and the Northern and Southern Limestone Provinces (early Oligocene to middle Miocene). Known precious metal deposits are generally small and occur in veins and shear zones within Lower and Upper Cretaceous volcanic and plutonic rocks. Some Tertiary igneous rocks are also mineralized. Selected indications of disseminated lithology-controlled mineralization could represent larger deposits. Associated metals in some deposits include copper, zinc, and lead. At present, tax policies, population density, political outlook, and lack of proven significant precious metal deposits discourage the establishment of a metal mining industry.

Jan 1, 1993

By W. Joseph Schlitt

Aqueous SO2 (sulfurous acid) is an interesting chemical compound. It functions as a reagent in various hydrometallurgical systems, but also represents an undesirable constituent in pyro- and hydrometallurgical effluent solutions. When present in such streams, SO2 can be oxidized to the more stable sulfate form to avoid exsolution of SO2 as a source of fugitive emissions and to simplify standard water treatment plant operation. This study provides information on the stoichiometry, kinetics and mechanism of SO2 oxidation using oxygen and an iron salt catalyst with solutions containing 0.05 to 20.0 g/l S02. Other test variables include iron salt concentration, oxygen pressure, temperature, degree of agitation and pH.

Jan 1, 1982

By Donald S. Skufca

This chapter focuses attention on major factors pertaining to plant design and general arrangement of equipment. Considered are efficiency of operations, coordination of maintenance and repairs, plant testing of reagents and possible future plant expansions. The design and general arrangement of equipment considers accessibility for maintenance and isolation for repairs, minimum personnel for operations and cleanup, safe working conditions with minimum interruptions to operations. The constant introduction of new reagents requires eventual plant testing and the manner of isolating a “line” or part of the facilities to allow comparisons in the testing of new reagents is discussed. As technology improves and process changes occur, additional equipment or plant expansions are inevitable. Space for these eventualities must be considered while the general arrangement drawings are in the development stages.

Jan 1, 1986

By A. R. Laplante

A test to determine the amount of gravity recoverable gold (GRG) in an ore is described. Typical GRG results are given; an error analysis is detailed; possible uses are discussed. Of the 38 samples tested, the lowest GRG content was found to be 25% (most below 25 11m, or 600 mesh), and the highest 94% (most above 300 11m, or 50 mesh). The average GRG content was 63%, with a standard deviation of 19%. Error analysis shows the test to be reproducible within 5 to 10%, depending on the size distribution and grade of GRG, and the sample extraction protocol. When using the same primary sample, reproducibility improves, 2 to 5%, depending on the amount of gold coarser than 850 11m (20 mesh) and sample weight. The test has been applied to greenfield project and retrofit applications, to determine the suitability of gravity recovery. For existing circuits, it has been coupled with a model of gravity recovery for optimization studies.

Jan 1, 1996

By W. G. Pariseau

"BACKGROUND The Crandall Canyon Mine (CCM) is located in the Wasatch coal field in central Utah. Extensive longwall mining at CCM preceded a decision to recover coal left in barrier pillars on each side of a set of main entries extending far into the mine. During mining in March, 2007, a major bump occurred that led to cessation of mining in the barrier pillar on the north side of the mains and to begin mining in the south barrier pillar. Subsequent loss of ground control in August, 2007, through coal pillar bursts had tragic consequences with loss of six miners and shortly afterwards three rescue team members. An MSHA report describes the events in detail (MSHA, 2008). An important lesson to be learned from CCM is the need to select a computer program suitable for pillar design. Computer programs are engineering tools; selecting the right tool for the job is essential. In this regard, a minimum program requirement is capability for computing stress distribution within a pillar and adjacent roof and floor strata. The reason is simple: strength of rock is stress dependent; both vary from point to point in pillars and adjacent strata. Preferably, one should follow the evolution of stress as the mining plan is executed from start to finish to assure safety or to warn of a potentially hazardous situation developing as mining progresses. The approach to the problem posed by barrier pillar mining at CCM is conventional in the sense of applying well known finite element modeling techniques to analysis of a proposed mining plan. The engineering purpose is to evaluate the mining plan with respect to ground control questions including roof, floor and pillar safety. Results of previous two dimensional finite element analysis indicated pillar safety was by no means assured (1, 2, 3). Geometry of barrier pillar mining is limited in two-dimensions, for example, crosscuts are not seen in vertical cross sections. While three dimensional analyses are preferred, even moderately sized regions often lead to very large problem sizes that exceed computer capabilities. However, a recent development in finite element modeling of tabular deposits allows for whole mine analysis in three-dimensions. This technique involves a dual node – dual mesh concept. Both have been used separately in much earlier work, but are only now are used in combination. Estimation of subsidence at a kilometer scale and details of stress, strain and displacement about barrier pillars, main entries and pillars, and so on at a meter scale are possible (4). No compromise involving empirical formulas or similar guess work is required. Indeed, all calculations are based on first principles: physical laws, kinematics, and material laws. Effects of joints and in situ variability or uncertainty in strata properties, elastic moduli and strengths, may be included for greater realism. An important objective of the present study is to assess the role of three-dimensional pillar geometry in arriving at conclusions regarding barrier pillar mining versus two-dimensional results."

Jan 1, 2015

By D. S. Bird

Kennecott Utah Copper began a modernization program in 1986 that was aimed at expanding and updating mining and ore process facilities at the company’s Bingham Canyon copper mine and concentrator near Salt Lake City, UT. Major components of the project included installation of an in-pit crusher, a transfer conveying system and a new ore concentrator with a design capacity of 70 kt/d (77,000 stpd). The Copperton concentrator was commissioned in February 1988. The grinding circuit is one of its principal features. It consists of three identical lines, each with a 10.4-m- (34-ft-) diam x 4.6-m- (15-ft-) long semiautogenous grinding (SAG) mill and two 5.5-m- (18-ft-) diam x 8.6- (28-ft-) long ball mills. The SAG mills are driven by two 4.5-MW (each) (6000-hp) variable- speed dc motors through a clutch-pinion gear-ring gear assembly. The ball mills are driven by 4.1-MW (5500-hp) synchronous motors coupled through a typical clutch-pinion gear-ring gear system.

Jan 1, 1995

By Edward F. Nagle

Instrumentation engineers have recently devised practical methods of metering the net solids flowing in a hydraulic mixture. The solids flow rate is determined by measuring the specific gravity and the flow rate of the mixture. T e specific gravity is measured by a variation of the bubbler system. The flow measurement is made by a somewhat unorthodox orifice requiring field calibrations. The linear mixture flow signal is then multiplied by the specific gravity signal, which is directly proportional to the percentage of solids in the mixture, to produce a linear solids Slow rate signal. The computations in this system are performed by Sorteberg pneumatic relays. Having obtained this measurement, integration and automatic control of hydraulic solids flow are available. This system is useful in mining, drilling and dredging industries. It provides maintenance of the net solids flow rate and reduces power consumption. Automatic control will provide rapid stabilization of net solids flow rate and release operators from making menual adjustments. The advantages of this application are economy of operation and increased pump efficiency, This paper describes a hydraulic solids flowmeter system installed aboard a dredge. Its purpose is twofolds:- 1. 20 provide a summation of the net solids flowing 2. To make available a practical guide for the drag tender operator. (Dwg. GSD-2219)

Jan 1, 1958

By Stanislaw Wasilewski, Zdzislaw Krzystanek

The CMC-3 new generation system for continuous methane monitoring enables on-line measurement of methane concentration within the range of 0-100% CH4 with a great autonomy of operation. In principle the system has been worked out in the asspect of hazard detection in mines endangered with rock and gas outbursts. But after last crash in the Halemba colliery, according to the recommendation of the after-accident committee, the system was directed to this colliery for operational tests. The paper describes construction and functions of this system and gives some results of tests conducted at the Halemba colliery. The results point out the necessity of using monitoring equipment of continuous operation in mines of high dynamics of methane emission. INTRODUCTION Commonly used in Polish coal mining the methane monitoring systems of CTT/63/46 Up or CMM-20 and CMC-1 type are based on cyclic measurements with 4-minute repetition of measurements. This period has been stated sufficient from viewpoint of methane emission dynamics under normal exploatation. In these systems, automatic switching-off electrical power is performed by the surface station, i.e in case of detecting exceeded concentration value the station generates control pulse signal which actuates the switchng-off devices CRA and IZZO. Such a way of disconnection causes a considerable time delay, up to several minutes, in electric power break at hazardous areas. In the methane monitoring system with the new CMC-3 station, the different phylosophy of operation has been applied. Measurement of methane concentration is performed in a continnous way. In case of exceeding the alarm value, immediate control of the IZZO unit directly by methane monitor follows and consequently energy break without necessity of communicating with the surface station. Alarm values are set directly in methane monitor. The system ensures central powering of underground equipment from the surface, and in case of power failure the methane monitor equipped with battery operates autonomously for about 12 hours. Such an extention of the methane monitor funtionality has been achieved thanks to the use of internal microprocessor controller. The system with the CMC-3 station has been worked out in the aspect of methane hazard detection in mines exposed to gas outbursts. But after last gas explosion, according the desicion of the After-accident Commitee, the system was installed in the Halemba coliery where it underwent operational tests. Besides

Jan 1, 1993

By K. D. Luxbacher, J. T. Davis

"A wind tunnel was designed to examine air flow, heat transfer and layering near an active fire at a working face. This tunnel simulates an active entry in an underground coal mine including an attached cross-cut of similar dimensions. A steel rectangular duct 1 ft. (0.305 m) tall, 3 ft. (0.914 m) wide and 10 ft. (3.05 m) long composes the main body of the tunnel and represents a mine entry. Air flow is generated by an exhausting centrifugal fan attached to one end of the crosscut. This fan was sized to supply air velocities based on Froude scaling. A 6 in. (15.25 cm) propane burner is used to simulate fires of various heat release rates at the working face. Thermocouples are used to map heat layering in the tunnel. Ports are installed for the introduction of tracer gases into and from sampling the system. Barometric, differential pressure, and temperature sensors are also included to monitor environmental conditions. Details about the design and testing of the system are presented including an overview of how the tunnel was scaled to accurately represent fire and flow phenomena. Finally, the proposed use of the tunnel for better understanding of mine fire phenomena and prevention is given. INTRODUCTION Fires in underground mines have been a concern since the dawn of mining. While technological advancements, regulations and best practices have improved both fire detection and firefighting techniques, mine fires continue to represent high risk events. From 2006 through 2015, fires accounted for 1.06% of fatalities in underground coal mines and 0.85 percent of fatalities in all underground mines in the United States (U.S. Department of Labor, 2006 to 2015). In addition to the risk of loss of life, mine fires can cause millions of dollars in equipment damages and lost production revenue. Extensive research has been conducted on how fires occur and spread in underground mines. In addition to testing conducted by government agencies such as the Mine Safety and Health Administration (MSHA) and the National Institute for Safety and Health (NIOSH) (e.g.(Liming, 2006), researchers like Verakis and Dalzell (Verakis, 1988) and Lowndes, et. al. (Lowndes, 2004) have furthered this field by studying ignitions and propagation of conveyor belt fires. While the studies of belt fires in mines are extensive, studies focused on fires at the working face are few in number. The particularly confined space and limited access to a working face, coupled with less robust, temporary ventilation controls create a unique environment that warrants special attention. Separate from studies on mine fires, the use of tracer gases to characterize flow patterns in normal mining ventilation is well established. In 1982, Timko and Thimons (Timko, 1982) outlined current and future applications of sulfur hexafluoride (SF6). However, little experimentation has been conducted to study specifically how tracer gases might be used to evaluate active mine fires and the fires’ effect on the surrounding mine environment (e.g.(Lindsay, 2014). In order to better understand the dynamics of smoke layering from a fire in an enclosed space, a small-scale apparatus was designed to map smoke layering and to examine other aspects of fire behavior at a working face. In addition to studying smoke flow around an active fire, experiments will be conducted using tracer gases in order to determine how they might be used to evaluate an underground fire."

Jan 1, 2017

By Eric K. Albert

Computer oriented simulation techniques can be effective in the design and analysis of complex mining systems. In fact, a number of computer software products are available for mine systems simulation. However, previous models have tended toward being either data-intensive and deterministic, or data-limited and highly stochastic. The need for a fully integrated package with a simplified user interface has never been more apparent. In this paper, the design of a surface mining simulation model documented in Albert (1986) is described. The basic features of the surface mining system and their counterparts in the simulation model are discussed. The methods and algorithms used to implement these subsystems are presented. Considerations of information management and software design are illustrated, especially as they apply to the application of the package by a mining engineer. An example is provided to demonstrate the concepts embodied in the model and to show how a surface mine is simulated from mine parameters.

Jan 1, 1989

By R. Duckett, D. Salisbury, R. Dorey

The Kennecott Ridgeway Mine in South Carolina is scheduled to complete mining and ore processing in the last quarter of 1999. Tailings are disposed in a 300 acre, lined tailings impoundment. To facilitate closure and reclamation, modification of the tailings impoundment operation has been adopted. Mining involved the sequenced development of two open pits. In 1996 mining of the South Pit was completed and backfilling of the pit with waste rock from the North Pit was initiated and will continue until mining ceases. Both pits will be reclaimed as fresh water lakes. This paper presents the physical, geochemical and hydrogeochemical evaluation of the operational and post operational management of the project. Comparison of the operational monitoring data against predicted performance are reviewed.

Jan 1, 1999

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 Clyde N. Garman

The Homestake-New Mexico Partners consist of Homestake Mining Company of Lead, South Dakota; Rio de Ore Uranium Mines, Inc; United Western Minerals Company; White, Weld and Company; J.H. Whitney; San Jacinto Petroleum Corporation; and Clyde Osborn, Homestake Mining Company is the general partner, the others are limited partners. The Rio de Ore Uranium Mines, Inc. has. a mine in the Ambrosia Lake area; this was the first mine to go into production in this area. The United Western Minerals Company also has a mine in the Ambrosia Lake which is operated as a "farm out" from the San Jacinto Petroleum Corporation. These mines are the principal sources of ore for the mill. This group was the first to obtain a contract with AEC to make uranium concentrate from Ambrosia Lake ores and the first to have a mill in operation specifically for these ores. With Clyde Osborn as the sparkplug and co-ordinator holding the ore suppliers of, this group together, a contract with AEC was agreed on as to its essential points by mid-summer, 1956, At that time, there was no general partner and no financing, so me formal contract could be signed. By December, 1956 when the contract was signed and the present partnership officially formed, much of the basic engineering was done and purchasing of main elements of the mill waited on the formalizing of agreements, at the specifications and sizes agreed on previously. Ground for the mill was broken in April, 1957. The sampling plant went into operation in October and ore was first fed to the ball mills on February 5, 1958, ten months after construction actually started. Filling of the circuit with sodium carbonate bicarbonate solution had begun a week before that.

Jan 1, 1959

By James G. Tilton

Throughout the world, sedimentary basins are exploited for many different minerals. Frequently, the extractive methods conflict with one another. A case in point is the proximity of oil and gas operations and the mining of coal. Generally, the interference between the two industries lies in the fact that the reserves over- lie or underlie one another. Mining of coal generally is developed on a rectangular pattern in a horizontal mode while oil and gas drilling is developed on a radial pattern in a vertical mode. Coal mining has exhausted vast acreages in various basins with many of those basins being drilled for oil and gas. Those existing wells create problems by requiring the unrecoverable coal pillars to support the well bore, or to make special provisions in order to mine through an existing well. The system works ... more or less; but there are little or no provisions made for additional drilling unless the vast majority of those new wells are drilled through mined-out sections (gob) of those mines. Many states have rules and regulations governing the drilling of oil and gas wells through gob; but, some companies and some regulatory agencies or personnel have deemed such drilling as a hazard to the mining operations. This paper explores the history, technical standards, and safety aspects of drilling oil and gas wells though the gob of worked-out and active mines. It is the opinion of the author that such drilling can be conducted safely while eliminating the re- quired changes in mine projections and the loss of recoverable coal in the form of well pillars.

Jan 1, 1997

By Thomas F. Stinson

Energy-producing states see severance taxes as attractive sources of increased revenues for otherwise tight budgets. Consumers in energy-poor states, however, protest that current rates are excessive and have moved to obtain a reduction. The US Supreme Court heard two cases questioning such taxes during its 1981 term, and Congress, in each of its last two sessions, has seriously considered measures placing a ceiling on severance tax rates. Although discussions usually focus on coal severance taxes levied by Montana and Wyoming, ramifications of changes in national policy are much larger, potentially affecting mineral taxes in all states. Severance taxes yield substantial revenues in some states, as illustrated in the accompanying table. In fiscal 1980, Texas collected more than $1.5 billion from such taxes, while Louisiana, Alaska, and Oklahoma collected $525 million, $507 million, and $436 million, respectively. Oil and natural gas production were the major items taxed. While the table shows only the 10 states with the largest severance tax collections, a total of 17 states had severance tax receipts exceeding $10 million in 1980. The enormous increases in severance tax revenue between 1970 and 1980 can be seen from the table by comparing columns A and B. For the 10 states shown, revenues increased from $650 million to $3.8 billion during that period, due to a combination of higher prices, increased production, and new or increased taxes. In most states, increases in prices and production were more evident than higher tax rates. Although the revenue increase is impressive, it understates the extent of changes occurring during the past decade. Since tax collections are shown for fiscal 1980, the full impact of the decontrol of domestic oil prices is not evident. Also, taxes on natural gas reflect controlled prices. When full de-control of natural gas occurs, significantly higher revenues can be expected in gas-producing states, even if tax rates, production, and world prices remain constant. These increases in severance tax revenues, coupled with further increases expected to accompany natural gas decontrol, have produced fears that a substantial transfer of income is taking place from residents of energy-poor states to those living in energy-rich areas. Others worry that increased severance tax revenues will be used to substitute for a substantial portion of state taxes that would have otherwise been collected from firms and individuals. The resulting improvements in tax climate, it is thought, may encourage firms and workers to migrate to energy-producing states. While these issues are often portrayed as pitting energy have-nots against the haves, such is not entirely the case. Much of the original impetus for limits on coal taxes came from Texas residents, the state collecting the most severance tax revenue. One way of gaining perspective on these concerns is by examining severance taxes per capita and as a percent of state tax collections (see columns C and D in the table). When this is done, Alaska, where 1980 taxes on oil and gas production totaled more than $1300 per capita (and 35% of all state tax collections), stands out as a special case. There, the state was able to eliminate some individual taxes, place revenues in a permanent trust fund, and consider offering a rebate of some previous income

Jan 4, 1982

By J. M. Barker

New Mexico is the leading domestic producer of perlite, a hydrated volcanic glass that can be expanded thermally to form a white, very porous, lightweight material. The United States is the leading consumer and producer of perlite in the world (Pettifer 1981). New Mexico produced, at five mines (Fig. 1), about 86% of all domestic crude ore mined in 1984 (Meisinger, 1985). Perlite is mined in 6 other western states, ore is expanded in 33 states, and the expanded ore is consumed in all states (Meisinger, 1985). Gross value of domestic ore mined in 1984 was about $16,500,000 (FOB mine; Meisinger, 1985) with much value added by expansion and processing prior to sale to end users. In contrast to the ubiquitous nature of perlite products in the U.S. economy, facilities for testing perlite ore, expanded perlite, and perlite products are notably lacking on a commercial, cost-effective, or readily accessible basis. The New Mexico Bureau of Mines and Min¬eral Resources (NMBM&MR) established a perlite¬testing facility in 1984 to mitigate this lack and to further the mining of perlite in the state.

Jan 1, 1985