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By Earl M. Frizzell, Ronald W. Utley

Introduction For the past several years the Bureau of Mines has undertaken research to develop alternative mine material haulage systems that will improve mine productivity, reduce haulage costs, increase mineral availability, and conserve energy. One basic concept being pursued is a means for crushing primary blasted rock to a size that can be reliably and economically moved on conveyors. During 1980, mine requirements for this equipment and the capability of existing technology to satisfy these requirements were assessed. The study continued into 1981 on the basis that satisfactory equipment for this purpose needed to be developed. The objective of the 1981 program was to perform an engineering design of such a system. A mine survey and equipment development study was conducted in cooperation with the open-pit mining industry by GATX through its subsidiaries, Fuller Co. (a crusher manufacturer) and GARD Inc. (GATX's research and development center), under contract to the USBM. Results of a mine survey in the copper, iron, and molybdenum industries indicated that a universal crusher system could be developed even though details might vary from mine to mine. The crushing characteristics, including tonnages desired, were similar in all surveyed mines. Most mines had similar views about the desirability and frequency of crusher movement. The perceived need for in-nit crushing varied between copper and iron mining. The copper mines felt a greater sense of urgency for introduction of such a system, probably because typically greater vertical haulage is found in copper mines than in the iron mines. All mine personnel surveyed were interested in portable crushers and almost universally preferred gyratory-type primary crushers. They preferred large crushers, citing inherent reliability and durability, and the machine's relative freedom from clogging. Large size minimizes the number of crushers and conveyors needed. Analysis of desired crusher system characteristics (Table 1) fixed the crusher size at 1.5 x 2.3 m (60 x 89 in.). The 1.5-m (60-in.) feed-opening dimension could accept the largest material normally fed to the crusher, and the 2.3-m (894n.) head diameter could fulfill the 3.63 kt/h (4,000 stph) capacity requirement. Selected System Description The comments and analyses discussed in the contract report led to the design and refinement of a movable crusher system. This system represents the consensus of more than 100 mine workers and almost 50 construction and engineering company personnel. It is supported by more than 50 years of experience in crusher manufacturing. Although many alternatives are available for any given system, and selections are likely to be dictated by varying site conditions, the selected system is believed to be appropriate for most projected requirements. Final design would be dictated by mine operators during evaluation for approved projects. Detail design of the feed and discharge systems were not included in the study because they are mine specific. The basic system (Fig. 1) consists of a 1.5 x 2.3-m (60 x 89-in.) gyratory crusher on a structural steel frame. The frame is used as an operating platform for the crusher and as a carriage to move the crusher. The control tower includes a crusher lubrication room, a hydraulic equipment room, a switch gear room, a room for the motor control center, and a control room for operating the crusher and maintaining the equipment. The auxiliary system consists of a hydraulic rock hammer and pedestal crane with 74-t (80-st) and 14-t (15-st) hooks. Figure 1 also shows stairs, railings, and a work platform. Feed and discharge arrangements are shown on Fig. 2. The system shown is for mildclimate applications. Additional enclosure and heating would be needed for extremely cold weather conditions. Crusher A 1.5 x 2.3-m (60 x 89-in.) gyra¬tory crusher was selected for this application. This size can handle the typical throughput of 3-3.63 kt/h (3,500-4,000 stph) desired by the mines and the 1.3-m (50-in.) material to be crushed without difficulty. The crusher is the heaviest

Jan 4, 1983

By T. W. Conrad, B. Kerr

During the last decade grassroots minerals education programs have blossomed throughout the United States and in other countries. At the same time an environmental education movement has been gaining momentum. While this offers a unique opportunity to share the mining industry’s story, it also has some potential pitfalls. In this paper the authors will discuss some of the benefits of participating in environmental education and provide some practical tips for success, based on New Mexico experiences. It will conclude with a presentation on a successful environmental education program at Heights Middle School in Farmington New Mexico.

Jan 1, 2001

By Ralph J. Anctil, James E. Palmer

According to relatively recent estimates by the US Geological Survey and the US Bureau of Mines, there are more than 0.9 Tt (one trillion tons) of remaining identified coal resources in the seven major western US coal-producing states and about 200 Gt (220 billion tons) in the demonstrated reserve base. Considering coal's current national production level of 0.7 Gt/a (0.8 billion tpy), these US reserve and resource figures are reassuring. Given here is a preliminary analysis of geologic constraints and an estimate of their effects on mining and recoverability of western coal. Mining Constraints USGS and USBM coal figures incorporate only thickness and depth, and are "blind" to many other major geologic constraints on mining and recoverability. The most important of these geologic constraints include: • coal seams too thin or too thick for conventional mining methods; • coal seams that cannot be mined due to insufficient separation from underlying or overlying previously-mined beds; • unstable or otherwise unfavorable roof strata; • soft or heaving floor strata; • coal seams that are too lenticular or discontinuous for conventional mining methods; • coal seams in intensely faulted areas; • coal seams having high angles of dip precluding the use of conventional coal mining methods; • coal seams that cannot be mined due to proximity of water-bearing strata; and • coal quality problems such as excessive ash, sulfur, chlorine, or sodium. Coal Thickness Present USGS-USBM classification for reserve base includes bituminous coal beds more than 0.7 m (28 in.) thick and subbituminous beds more than 5 m (60 in.) thick to depths of 305 m (1,000 ft). Both of these thicknesses are less than the thicknesses now considered mineable in the western US. The lower limit for bituminous steam coal in deep mines is about 1.5 m (5 ft). For subbituminous coal, a thickness of at least 2.4 m (8 ft) is generally required. Accordingly, the Bureau of Mines reserve base includes many thinner coal seams that will not be mined in the foreseeable future. Within the Powder River Basin of Wyoming and Montana many seams-Wall, Upper Pawnee, Lower Pawnee, Cache, Manning-range in thickness from 7.6 m (25 ft) to more than 30 m (100 ft) and occur at depths to 305 m (1,000 ft). These have been included in the Bureau of Mines reserve base. However, the mining technology required to mine these thick seams does not now exist. It will require many years for development. The ultimate recoverability from these thick seams is unknown, but could be as low as 25%.

Jan 8, 1982

By A. W. Laughlin, C. R. Mansfield, M. J. Ferris, D. A. Cremers

Analytical costs are a major part of exploration programs in developing nations which may lack adequate laboratories. Laser-Induced Breakdown Spectroscopy (LIBS), a variant of atomic emission spectroscopy, can reduce exploration analytical costs and can provide the analytical results in <1minute. CPI is now marketing battery-powered, backpack mounted analyzers, using LIBS to analyze for many elements of interest to the explorationist. LIBS is well suited to the analysis of elements in industrial minerals. Limits of detection in ppm for some of these are: Li-1, Be-2, Na-100,B-33, Sr-10, Ba-300, Cs-1, K-500, Fe-500, Mg-500, andTi-500.

Jan 1, 1999

By Syd S. Peng

Introduction Modern longwall mining, introduced to the US coal industry in the mid-1960s, is the latest coal mining technique. Today, longwall mining produces more than 15% of all underground coal production. The growth of longwall mining in the US is slow. However, nearly two decades of longwall mining have demonstrated that its benefits outweigh the disadvantages. Longwall Advantages Production and Economics - A typical longwall production ranges mostly from 0.9 to 1.8 kt (1000 to 2000 st) of clean coal per shift. This is about three to six times the production of comparable continuous mining units. Furthermore, there are much less rejects in longwall mining, typically 15% to 25%. It must be noted, however, that a new longwall with an inexperienced crew may produce less, depending on mining conditions. But as experience gains, production increases rapidly. Due to its high production, the cost per ton of coal mined over the mine&apos;s lifetime is cheaper with longwall mining than with continuous mining. A study on a conceptual mine of 25 year life using actual operational data (Dangerfield, 1981) concluded that the cost per ton of coal mined is 32% cheaper by longwall than by continuous mining. Another benefit from its high production potential is that it enables the production to be concentrated in a few longwall faces versus many units of continuous mining required to achieve a similar production. As a result, mine organization and management simplify considerably. Safety and Savings - Most US longwalls use shield supports that cover the roof with solid canopy and isolate a gob completely from the face area. Thus, if the supports are properly selected and operated, the potential for roof fall accident is almost zero. Furthermore, it is not unusual that a well-run longwall face is much more orderly and cleaner that most well-run machine shops. The ventilation system for longwall mining is the most ideal type. It is simple and unique. No auxiliary fans are required. The fresh air sweeps through the whole face. Its volume and velocity can be adjusted as demanded. Recovery - In spite of multiple entries layout for US longwall panels, the longwall method recovers up to 40% more coal than the continuous mining method (Dangerfield, 1981). The typical recovery for longwall mining is 70% to 85% versus 45% to 80% for continuous mining. Versatility - Longwall mining has been employed successfully in seam heights ranging from 0.8 to 3.7 m (2.7 to 12 ft); in seam inclinations from horizontal to 35°; in overburden depths from 46 to 914 m (150 to 3000 ft); in single or multiple seam mining; and in uniform or irregular seam characteristics. For seam height less than 1.2 m (4 ft), the plow is used instead of a shearer. However, in spite of recent developments, the plow still is unsuitable for hard coal seams. Slow Acceptance How come longwall mining, with so many advantages, has not spread more rapidly? Undoubtedly, the major reason is the large capital investment required. Under normal market conditions, the capital required for a longwall panel ranges from $7 to $11 million. Another factor is the uncertainty of its applicability to any specific coal seam of interest where longwall has not been used or operated successfully. Although longwall mining elsewhere has proven its applicability to wide-ranging seam conditions, there have been several failures in the past two decades. Analyses of those cases show that most failures can be attributed to inexperience, both operational and technical, including equipment selection. Therefore, personnel training on the longwall mining technique is absolutely necessary before its initial operation. Some earlier statements about adverse surface subsidence associated with longwall mining were misleading. Research has proven that surface subsidence under longwall mining is controllable and predictable. And, if longwall mining was mandatory since the onset of coal mining in the US, there would be no surface subsidence problems over abandoned mined land today. It is a blessing that surface subsidence occurs

Jan 3, 1985

By T. G. Bobick

Task analyses were conducted by the Bureau of Mines at four underground low-seam coal mines to evaluate their supply-handling systems and for use in subsequent design of laboratory simulation experiments. Items were tracked (by videotaping) from delivery to the surface storage areas to their final destinations underground. Of particular interest were those tasks that required manual handling of supplies or equipment. Analysis of the videotapes revealed that the miners handled materials while stooped over a total of 37.8 pct of the time, 31.5 pct while on both knees and 9.5 pct while kneeling on one knee. These working postures impose considerable stress on the lumbar spine and may be implicated in the high number of back injuries in this work population. This paper also discusses various mechanical-assist devices developed by the Bureau and successfully evaluated in the underground workplace. These devices can be used to minimize the manual effort and the corresponding risk of injury associated with handling supplies and equipment components in low-seam coal mines.

Jan 1, 1988

By R. Matikainen

Since the Brundtland Commission in 1987, the use of natural resources has been an issue of global concern. Minerals are among the most important Earth resources and will definitely be essential for the development of societies also in future. Increasing scientific effort is needed not only to discover new deposits, but also to promote resource management in ecologically and socially sound way. Sustainable resource management is essentially a multidisciplinary challenge of developing life-cycle analysis and recycling of non-renewable resources from local to global scale. It offers great opportunities for geological surveys not only in EU, but all over the world to contribute positively to the welfare and sustainability of societies.

Jan 1, 2003

By Julia R. Budden, Peter A. Spencer

Bacterial oxidation processes have often been repo1ted as releasing large amounts of energy so that a large scale operation would require cooling to maintain the required operating temperature for the bacterial culture. These reports are based on the chemical heat release which in some eases has been adjusted for the energy required to fonn the mass of bacterial cell matter per unit volume of solution. There are two flaws in this approach for calculating energy release in the fonn of heat. The first flaw is that it only considers the bacteria in solution. The second assumption is that the only bacterial reaction is the fonnation of cell material and others such as energy for respiration and locomotion are not considered.

Jan 1, 1992

By N. S. Margaris

The vegetation of Mediterranean ecosystems is distinguished by its resistance to adverse environmental conditions, and that is the reason for examining the possibility of growing species of this flora in waste disposal sites (WDSs). The survival and growth of vegetation established at a waste disposal site is dependent to a large extent on the qualitative and quantitative characteristics of the material used in the final soil cover. In the Ano Liossia WDS, where extensive remediation work is under way, three areas were examined, which met certain criteria in relation to the age of the underlying waste and the existence of impermeable material in the final soil cover. Laboratory analyses have determined soil parameters and nutrient and heavy metal content. Alongside this, at all three sites a network has been installed to monitor the qualitative characteristics of the gaseous phase of the soil cover material. The results showed the existence of a soil material containing few nutrients and the prevalence of oxygen-poor conditions, accompanied by large concentrations of CH4, CO2 and H2S, at depths of up to about one meter.

Jan 1, 2002

By Alf Thidemann, Per Marius Nilsen

Tunnelling with hydraulic drills has been a success in Norway. In the fall of 1976 excavation of tunnels for the development of the Aabjoera scheme was started. Two and a half years later a total of 25 kilometers of tunnels are completed. During the most busy period 5 rigs with hydraulic drills were in operation. GENERAL INFORMATION. Aabjoera Hydro Electric Plant is located in the central part of Norway (Fig. 1). The scheme covers a mountaineous area between the Tosen Fiord and the valley of Namdalen. Water from the area of precipitation is transferred through 5 tunnels to the main reservoir. From here the water is conducted via a 10 km long, unlined supply tunnel down to the Kolsvik power station. The power station is situated underground with a short tailrace tunnel out in the fiord. Average head of water is 507 m. The Aabjoera plant is jointly owned by Helgeland Kraftlag A/S, 8650 Mosjøen and Nord-Trøndelag Elektrisitetsverk, 7700 Steinkjer. The Civil Engineering Division of the latter company has acted as Consulting Engineers for the scheme. General contractors for the whole scheme has been Ing. F. Selmer A/S, Box 6035, Etterstad, Oslo 6.

Jan 1, 1979

By J. R. Stoltz, E. Thompson, S. Pattee

On May 15 and 16, 1999, a mine ventilation survey was performed in the 705-m- (2,312-ft-) deep Cayuga Mine, Cargill Salt Division, Lansing, NY. The purpose of the survey was to develop a numerical model of the existing ventilation system and to perform a computer simulation study for long-term environmental and ventilation planning. Because the natural ventilation pressure (NVP) has significant effects on the ventilation system at the Cayuga Mine, there was a need to assess the NVP acting in the mine. Due to the ventilation arrangements in the Cayuga Mine, the authors decided to use the direct-measuring method to determine the NVP by measuring differential pressure across the automatic fan door. This difference in pressure was measured immediately after the fan was stopped and the automatic door was closed to stop the flow throughout the entire mine. To show seasonal changes in NVP, two additional measurement for NVP were performed, one on Aug. 22, 1999, during the hot (summer) season, and another on Feb. 6, 2000, during the cold (winter) season. The mutual interaction between the natural ventilation pressure and the main fan at the Cayuga Mine is also discussed

Jan 1, 2003

By F. Schreiter

"One method to increase the exploitation rate of a mine is the use of backfill with residual materials in exploited areas. The backfilled material is meant to support both, the walls of galleries and pillars as well as the roof of mining openings. With increasing depth, the exploitation rate diminishes fast, thus the application of backfill in order to change the layout of the mine is crucial for economic success. In result of using backfill, it is possible to change the layout of the working area with a higher ratio to excavated areas and less area occupied by pillars. Thus it is possible to boost the output of a mine by using backfill. Setting the criteria for the selection of the best possible materials and whose improvement, it is useful to know about their qualities and handicaps. The Mining Department at TU Bergakademie Freiberg is analyzing the parameters of residues from different processing methods, accrued in plants of different potash mines and blending different residues for optimization of material attributes. These were significantly characterized by basically parameters like the size and the distribution of different diameters of the grain material. INTRODUCTION The chair for underground mining methods at TU Bergakademie Freiberg is tasked with the sufficient and sustainable supply of economics with raw materials. The steady high demand, the rising prices and the finiteness of the deposits are reasons for the need of an optimized economic utilization of natural deposits, a continuous improvement of mining technics and technology. From an ecological and economical position the best possible utilization of the resources has to be achieved. Many mining operations are by reasons of the deposit not able to haul valuable minerals only, they have to haul a mixture of valuable minerals and waste rock. This hauled combination is given into the processing plant for separation and enrichment of the valuable mineral. The residuals of the processing are commonly dumped to a waste rock pile. For minimizing the size of such a waste rock pile and also minimizing the ecological footprint of a mining operation the only way is minimizing the quantity of accruing waste rock material. Both, optimization of economic utilization and also minimization of waste rock dumps can be realized in one by backfill with processing waste rock material in mined out areas. Especially in mines, mined by room and pillar method, smaller dimension of the pillars are sufficient for safety and stability. By the way less valuable minerals have to be leaved back in the mine and the mine outcome is increasing."

Jan 1, 2015

By Mehmet Maral

Various types of Tertiary (Miocene) lignite occurrences had been formed and alternated with volcano-sedimentary Bigadiç Formation in the field of study, which resides in the middle and eastern parts of Biga Peninsula. The focus of the study is to identify the geochemical and petrologic properties of coal occurrences and the formation mechanism of the deposits. A comparative study of the deposits will also be studied. Biga Peninsula is a very rich zone in terms of both metallic ores and industrial minerals. Most of the metallic deposits and industrial occurrences in the region have been known and mined throughout the history. This richness of the region is related to the volcanic and tectonic activities that have developed during different geological periods. These activities are the main reasons of weathering and alteration phenomenon.

Jan 1, 2005

By M. Ghoreychi, M. Fauueau, P. Lebitou, P. Berest

A brief study of the history of gas caverns in salt formations enables us to consider creep mechanism in a cavity as a phenomenon of dissymmetrical deformation. Among different parameters affecting such a phenomenon, gravity forces, especially in large caverns, seem to be responsible for important bottom heaves as compared to roof releases. This fact is demonstrated here by means of certain theoretical considerations concerning elasto-viscoplastic constitutive laws relevant to rocksalt rheological behavior.

Jan 1, 1986

By James R. Miller

Recent experience over extensive areas of the Basin and Range Province has demonstrated the importance of the basin&apos;s (valley&apos;s) geology and geomorphology in locating large quantities of good-quality aggregate. First, a geologic map depicting basic geomorphic-geologic units in a valley is made in the office from aerial photography. Next, derivative maps are made from geologic maps and field-derived information such as parent rock type, source area and depositional environment, relationship to adjacent deposits, and Quaternary geologic history. Studying the derivative maps leads to selection of test sites for potential deposits of high-quality aggregates. Subsequent field studies provide more detailed information about geologic processes and samples for laboratory testing. Combining all information allows the characterization of aggregate potential of very large areas. Favorable areas can be further tested. This phased approach has proven to be cost effective. The methodology used in mapping and characterizing basinfill deposits is applicable over much of the western United States. Map units were developed by focusing on the predominate geomorphic process, grain size, cementation, and relative age. The resulting functional map units are of use to engineers and planners. This study led to many conclusions, including the fact that the best quality basinfill aggregates are found in selected alluvial fan deposits and Pleistocene lakeshore deposits. The best quality aggregates are derived from Paleozoic carbonate and quartzitic parent materials that can also provide high-quality crushed-rock aggregates.

Jan 1, 1987

By Takahide Wakamatsu, Junji Shibata

Complex polymetallic sulfide ore deposits occur in Tohoku district, northern part of Honshu island, Japan. The ore is locally called "Kuroko” ( black ore ) and is compactly composed of fine grained sulfide minerals of such principal metals as copper, lead, zinc and iron. Currently one of Kuroko mill plants is producing such concentrates as copper, lead, zinc, pyrite, barite, and clay minerals, mainly employing differential flotation techniques. This paper describes briefly the progress of techniques in Kuroko processing over the past thirty years and also the present state of Kuroko processing and its challenges to be studied and overcome in the future.

Jan 1, 1989

By Hayward B. Oblad, Anthony G. Fonseca

Coal flotation has been practiced since about 1920 in Europe and since about 1926 in the U.S. Over 200 U.S. coal preparation plants now use the process to recover coal. Over the 60 year period, the fundamental principles upon which flotation is based have been enumerated, but the interaction between the parameters that affect flotation has not been quantified and a useful model which accounts for these parameters has not yet been developed. A comprehensive and user friendly kinetic model coupled with better process monitoring and control instrumentation would allow plant operating personnel to better predict flotation performance and better control the flotation process in coal preparation plants.

Jan 1, 1989

By Malcolm J. McPherson

Within the world of mining health and safety, increasing attention is again being given to underground fires and explosions. This paper reviews the effects of open fires in mine entries on the ventilation system, and outlines current methodologies of attempting to control such a fire. The particular hazards of a fuel-rich fire are discussed. There appear to have been no really significant advances made in methods of extinguishing mine entry fires in the last several decades. The final section of the paper introduces research that is investigating the simultaneous production of an inerting, cooling and quenching atmosphere by means of a dense water fog.

Jan 1, 1993

By Rolf Hindstroom

Outokumpu Mintec started development of the pressure filter in 1991, and the first unit was delivered to Tara Mines Ltd. Ireland in 1992. The filter replaced a conventional disc filter and a thermal dryer. The replacement of the thermal dryer has improved both environmental and working conditions. The filter is currently dewatering 80,000 tons per year of lead concentrate, producing a cake with less than 6 wt % residual moisture.

Jan 1, 1995

By Henry E. Bakkila

Introduction United States Steel Corporation&apos;s, Texas Uranium Operations operates in-situ mines located approximately 70 miles north of Corpus Christi near the town of George West in Live Oak County, Texas. In 1977, Texas Uranium Operations became the operating entity for the Burns Ranch mines 100% United States Steel ownership and also operates the Clay West mines a 50150 joint venture of United States Steel Corporation and N M Uranium, Inc. Until mid-1982, Texas Uranium operated eight (8) satellites where uranium was captured on resin and two central plants where the loaded resin was eluted, acidized, precipitated and dried to yellowcake. At present, the Clay West Central Plant is operating, as are four (4) satellite plants in a mode designed to optimize results while depleting remaining reserves. United States Steel&apos;s Texas Uranium Operations, as have some other uranium producers, managed to continue successful production during the plunge to the recent floor price of $17. Despite the fact that United States Steel does not intend to continue as--a uranium producer beyond the life of its present reserves, we naturally hope the recent trend to the pre- sent price of $24 will continue to increase.

Jan 1, 1984