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By David J. Brown

Extensive deposits of bituminous, subbituminous, and lignite coals occur in the western United States (Figure 1). Over one trillion tons of identified resources have been located and inferred by geologists and more than 200 million tons of western coal are mined annually (1). In the future, production of western coals will increase significantly and approach national production levels of higher-rank eastern coals. Western coals will be utilized in new power plants as a replacement fuel for oil and gas and may be used in advanced technologies such as diesel engines or in direct-fired turbines. Since these applications require low-ash, low-sulfur coals, crushing to fine sizes and significant cleaning to remove minerals and sulfur will be required. Coal cleaning traditionally has been associated with reducing pyrite and other mineral matter from high-rank eastern coals. To date, insignificant quantities of western coals have been cleaned before utilization and limited data on their washability characteristics exist. Because of this lack of data, it is difficult to predict how these coals will react to standard washing techniques.

Jan 1, 1985

By Malcolm Ross

Fibrous minerals are common in nature but asbestiform minerals are rare. The unique mineralogical characteristic common to all the asbestos minerals is their morphologic form (or habit of crystallization) as polyfilamentous fiber bundles. The individual fibrils within the bundles have a tendency to be very long with a narrow range of diameters and grow with their long fiber axis in parallel orientation to the bundle length. The asbestiform habit imparts to the asbestos minerals sufficient flexibility and tensile strength so that most can be woven into cloth. In the past application has focused on their ability to insulate against the transfer of heat. However, these minerals possess other properties which make them useful in many industrial applications. © 2007 Elsevier Inc. All rights reserved. Keywords: Asbestos; Asbestiform; Fibrous

Jan 1, 2007

By A. Guzman

The design and construction of a new 140-ton-per-day R. O. M. phosphate rock scrubbing and washing plant was undertaken by Western Knapp Engineering Company, a Division of Arthur G. McKee and Company, for the J. R. Simplot Company, Minerals and Chemical Division, Pocatello, Idaho. The new plant replaces the owner's existing facilities at Conda, Idaho, seven miles northeast of Soda Springs in the southeast corner of Idaho. Replacement of the existing facilities became necessary because of loss in production and recovery. These losses were due in part to varying grades of raw ore from the mine and to the type of process equipment used in the old plant to upgrade the ore. Increase In production and grade was further necessary by demands created by expansion of facilities in Pocatello, Idaho, where all process ore from this plant is shipped. The new process scheme includes an ore-feeding system, scrubbing, screening, classification, wet cycloning, attritioning, filtering, drying, storage and shipping facilities. Space was also left for future increases of scrubbing and classification capacity and for heavy media separation. It is the purpose of this paper to take up some of the considerations necessary in the design of small mills in order to achieve the desired objectives of a successful plant, such as production, minimum operating cost and maintenance cost.

Jan 1, 1969

By T. D. Murphy

In the fall of 1988 it became evident that the accuracy of sulfur forecasts for Monterey Coal's No.1 Mine needed to be improved. In addition, it became necessary to predict if any individual train shipments during a month would exceed a contract sulfur limit. The challenge was to develop a forecasting process that would take into account the variability of the coal in the ground as well as the difference between laboratory and preparation plant sulfur reduction efficiency, and the effects of mining coal with multiple units. This paper describes how geostatistics and simulation techniques were used to meet this challenge.

Jan 1, 1992

By Sabina Brady

Nearly a decade and a half after the US and China established formal diplomatic relations, and two decades after the two countries signed the Shanghai Communique and established commercial ties, the world, and perhaps China itself, has discovered that a wealth of natural mineral and energy resources lie beneath China's soil and directly off its coast. The country's coal reserves and oil and gas potential are well known. Its ferrous and nonferrous metal reserves are respectable and in a number of instances pre-eminent. According to 1981 Minerals Yearbook estimates - more often than not below those now being claimed by China - the country's aluminous metal reserves are about 907 Mt (1 billion st); iron ore reserves are 40 Gt (44 billion st); and copper reserves are about 46 Mt (54.4 million st) of contained metal. In addition, the country has about 10.7 Gt (11.8 billion st) of phosphate reserves, the fourth largest in the world, and 3 Gt (3.3 billion st) of pyrite. China's national Sixth Five Year Plan promulgated in late 1982 ended a stringent three-year retrenchment or readjustment period in which a number of major development projects involving foreign participation initiated in the late 1970s were shelved. The new Five Year Plan is a signal both within and outside of China that things are now moving again, and that major industrial and service sectors are receiving the kind of funding and flexibility they need for expansion, construction and modernization. The new plan's strategy for growth is measured and much less grandiose and frenetic than it was five years ago when China flung open its doors to foreign companies and invited participation in large-scale development projects. Now, the country's reticence to spend foreign exchange to purchase key equipment, technology, and services -a reaction to these projects and the spending they entailed - is clearly on the wane. In China's effort to quadruple its GNP by the year 2000, there is a new willingness to use some of its substantial foreign reserves. In fact, it is projected that 1983 will witness a $1.9 billion deficit, with a $2-3 billion deficit in 1984 and 1985. The following article discusses implications the Sixth Five-Year Plan has for nonferrous metal development in China. It is the first in a series of three articles on Chinese mineral resource development to be published in Mining Engineering over the next few months. The second article will identify specific nonferrous projects underway, while the third in the series will focus on trade and development opportunities for phosphate and potash producers in China. China's Ambitious Plans In the last few months, the exploitation of China's nonferrous resources and development of its industrial processing capabilities have begun to receive increasing attention on both provincial and central levels. Unlike the earlier modernization drive of 1978 when China's ferrous sector - best typified in the Baoshan iron and steel project - got the lion's share of the Ministry of Metallurgical Industry's (MMI) energy and resources, it now appears that in some respects the nonferrous and industrial sectors are finally moving out from beneath the dominating shadow of ferrous and getting their own day in the sun. Separation of Nonferrous from Ferrous One clear demonstration of this is the establishment in April 1983 of the China Nonferrous Metals Industry Corporation (CNFMIC). The corporation is composed of 819 enterprises with over a million workers, and also includes 12 nonferrous metal construction companies, eight design institutes, and three prospecting companies. Of ministerial rank, CNFMIC is responsible for the development of both the country's nonferrous resources and its processing facilities. Although closely tied to the parent ministry from which it sprang (i.e. MMI), CNFMIC, at least theoretically, is separate and independent from it. One strong indication that this independence is, or soon will become a reality, can be seen from the fact that the new corporation is not headed by the former MMI officials, not even those who made up the ministry's now defunct nonferrous bureau. Instead, its president Qiu Chunfu is formerly of the State Economic Commission and the China International Trust and Investment Corp. Its general manager Fei Ziwen, an engineer in his early 50s, is from the Jiangxi Province Copper Corp. The new nonferrous corporation appears to be powerful

Jan 7, 1983

By Dirk Bleazard

Barrick Goldstrike Mines is improving the reliability of mining and processing equipment through the use of failure analysis and condition monitoring activities. Program results include an increase in equipment capacity and an overall reduction in operating costs. Identifying equipment failure modes and developing associated capital asset management practices can minimize failure consequences. Successful programs have included alterations to management practices, equipment modifications, and/or the implementation of condition monitoring programs. By controlling or minimizing the effects of incipient equipment failures, corrective actions can be taken earlier in the failure cycle. This results in an associated reduction to repair costs and equipment down time. Mining companies invest in their capital assets to provide the capacity necessary to meet operational needs. Over time, functional failures occur that reduce this productive capacity. Diagnostic technologies now exist that allow the condition of equipment to be monitored. Early response to this information minimizes the effects of functional failures and restores equipment re- liability. Reliability is a performance indicator of overall equipment condition. It is most often expressed in terms of mean time between failures. When the established objectives of a capital asset management program include the maximization of this failure interval, trailing indicators, such as availability and operating cost improve. The probability of equipment failure is influenced by engineering design and operating conditions. The performance level resulting from this operating environment is expressed as "inherent reliability." Without maintenance intervention, equipment will ultimately fail to perform its intended function and become less reliable. Therefore, maintenance must be managed as the supplier of reliable operational capacity. Maintenance can only supply equipment performance that approaches the level of inherent reliability. Actually achieving inherent reliability requires that all maintenance decisions are made at the economically optimal time. Enhancing performance levels beyond inherent reliability can only be achieved by altering operating conditions or practices or through physical equipment modifications. An evolution in maintenance management philosophy has been under way since the beginning of the industrial revolution. As equipment has become more sophisticated, so have maintenance practices. At the beginning of the industrial age, equipment tended to be over designed and slow moving. The first maintenance philosophy was one of reactive maintenance. Maintenance intervals were dictated by the operational status of the equipment. As a result, production interruptions were common and capacity needs were met through an investment in redundant capital assets.

Jan 1, 1998

By Karin Bäppler

Hydropower produces almost two-thirds of the world’s renewable electricity generation and delivers a major contribution on the ambition of the Paris Agreement and Sustainable Development Goals (SDG) with a range of benefits to society and environment. These include clean and flexible generation and storage in addition to reduced dependence on fossil fuels and avoidance of pollutants. The Limberg III PSP is one of the European projects that addresses the implementation of the UN SDGs. The challenge of the project is the construction of a 770 m long pressure shaft to be excavated with a TBM at an inclination of 42°.

Jun 13, 2023

By Neal Rackstraw, Mamo Meaza

Washington Metropolitan Transit Authority Section E8a consists principally of twin tunnels 1,713 meters (5,620 ft) long, excavated to a diameter of 6.35 meters (20.83 ft) using an open face shield, with a primary lining of four unbolted precast concrete segments expanded at the crown, and a full circle unreinforced concrete final lining with a finished tunnel diameter of 5.08 meters (16.67 ft). The tunnels, constructed in Cretaceous age sediments, are mostly in stiff to hard clay except for a few areas along the alignment that contain dense to very dense fine sand in the upper portion of the tunnel that created a mixed face condition. At two locations unexpected heavy water inflows produced very serious problems in both tunnels. Water flows in the interface area were generally more than 378.5 1pm (100 gpm) and reached as high as 2,649.5 1pm (700 gpm) in the mixed face ground. The nature of the tunnel inflows, the consequences, and the corrective measures adopted will be the subject of this paper.

Jan 1, 1991

By J. F. Colinet, W. R. Reed, J. D. Potts

Dust surveys were conducted at six underground coal mines to determine if deep-cutting practices expose face workers to higher levels of respirable dust. The surveyed mines were able to successfully mine deep cuts without significantly increasing the dust exposures of face workers. In general, all of the selected mines exercised good dust control practices by maintaining water sprays, scrubber airflows, proper curtain setback distances and providing sufficient airflow to the active faces. For exhausting face ventilation, field data indicate that scrubber airflow is the most important factor for controlling dust. Data collected for this study indicate that 20-mesh screens should be cleaned for every 12.2 m (40 ft) of advance, because 22% of the deep cuts surveyed for this study experienced a 20% to 35% decrease in scrubber airflow over the course of the cut. For blowing face ventilation, field data and past research indicate that dust control is aided by maintaining a proper curtain-to-scrubber airflow ratio of 1.0 (measured before scrubber activation), as well as a curtain setback distance that allows the miner operator to stand at the mouth of the curtain for the entire cut. Dust levels on the bolting faces did not appear to be affected by the longer cycles associated with deep-cut mining when good ventilation practices were used.

Jan 1, 2011

By A. F. Barsotti

Apart from jewelry, holistic apparel, and special collections of color and sometimes rare crystal specimens, the average layperson has little or no appreciation of the omnipresence of minerals or mineral derived products in the home. From concrete in the driveway to aspirins in the medicine cabinet, minerals, especially industrial minerals, play a major role in day to day living. For a better appreciation of this let's look into the a day of the life of a fellow named John, and see how much we depend on industrial minerals. The sounds of soft violins nudged John from his sleep. The melodic sounds of Beethoven's Pastoral coming from his radio alarm clock brought him out of his dreams. He reached for the reading light switch, then checked his watch--6:30 a.m., and another day of work. As he got up, the darkness outside reminding him of winter coincided with the soft voice of the all night disk jockey forecasting the fall of four inches of snow. Warm beads of water beating on his face removed all remnants of sleep and, like a stimulant, the morning shower brought thoughts of yesterday and plans for a new day. These carried over as he looked himself in the mirror while shaving and brushing his teeth.

Jan 1, 1993

By J. R. Blair, D. P. Lindroth, W. R. Berglund, R. J. Morrell

The objective of this US Bureau of Mines (Bureau) research was to determine the technical feasibility, principles and effectiveness of a combination energy method for drilling and cutting hard rocks. Experimental test results of microwave heating and drilling in basalt and granodiorite are given. The experiments were performed with pilot-scale, commercially available equipment employing microwave energy at a standard industrial frequency of 2.45 GHz. The data indicate that penetration rates, well in excess of the state of the art, are possible.

Jan 1, 1993

By F. Ikumapayi

Hydrogen peroxide production was measured during the grinding of a complex sulfide ore, and its oxidizing effect on solid surfaces was investigated using Fourier transform infrared spectroscopy (FTIR) with diffuse reflectance attachment measurement. In turn, an attempt was made to correlate the formation of hydrogen peroxide, surface oxidation and sphalerite flotation. Additionally, in order to predict and minimize detrimental production problems due to the recycling of process water in sulfide ore processing, the effects of major components of calcium and sulfate species present in recycled process water and the effect of temperature on sphalerite flotation were investigated through bench-scale flotation tests using complex sulfide ores. The significance of process water species in flotation was studied using tap water, process water and simulated water containing calcium and sulfate ions. Formation of hydrogen peroxide was revealed during the grinding of the complex sulfide ore, and its formation was counteracted by diethylenetriamine (DETA). The FTIR spectrum of the pulp solid fraction showed varying degrees of oxidized surface species, which are related to the concentration of H2O2 analyzed in pulp liquid. Bench-scale flotation using two different complex sulfide ores showed that sphalerite recovery is better in process water than in tap water. Flotation results also indicated a varied recovery of sphalerite at different temperatures in either tap water or process water.

By B. A. Ashley

In 2007, Rosebud Mining Company (RMC) opted to extend the reserve base of Tracy Lynne Mine by developing through a sandstone channel. The extension provided access to approximately 6 million additional recoverable tons (approximately 8 years of mining) which originally had been deemed inaccessible. An evaluation of the mine?s existing ventilation system, which was designed to meet the needs of the original limited reserve, concluded that two ventilation shafts would likely be required to adequately ventilate the projected workings in the expanded reserve. To assist in the evaluation, a ventilation model of the mine was developed using Ohio Automation?s ?ICAMPS MineVent? software based on field data from Tracy Lynne Mine, prior ventilation survey experience at similar RMC mines, and relevant published sources. Model results suggested that the most economical shafts would be an 8-ft diameter return and a 4-ft diameter intake. Unfortunately, issues related to property leasing and shaft site permitting caused construction delays. Therefore, the model was also used and proved to be effective in prioritizing interim ventilation upgrades which could be implemented in order to maintain coal production. Model results indicated that the best interim upgrades included rehabilitating restricted entries and damaged stoppings and replacing the main fan with a higher pressure fan. From late 2010 to mid-2012, all interim upgrades and shafts were implemented. Current models and mine experience indicate that ventilation will not be the limiting factor for mining the additional reserve.

Feb 23, 2014

By C. D. Litton

Laboratory experiments were conducted to determine the responses of a prototype smoke detector and a commercially available photoelectric smoke detector to smoke particles generated from various combustion sources. The prototype smoke detector combines optical scattering measurements with ionization chamber measurements in order to reduce/eliminate nuisance alarms due to the presence of airborne dusts or diesel exhaust particles. The commercially available smoke detector is designed for use in harsh environments where airborne dust represents a major problem due both to nuisance alarms and detector contamination. In the experiments, the responses of the two detectors were measured when exposed to smoke particles from the exhaust of a diesel engine and from a variety of fire sources, including wood, coal, styrene butadiene rubber, and No. 2 diesel fuel. For the solid fuels, data were obtained for both smoldering and flaming combustion. This report describes the experiments, their results, and the use of these results as they apply to early-warning fire sensors capable of the rapid and reliable detection of fires in atmospheres that may or may not be contaminated by either airborne dust or the products produced from diesel engines. Subsequent to these laboratory experiments, six smoke detectors were installed in an underground limestone mine for further testing and evaluation. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

On longwall coal faces in some Japanese coal mines more than half of the air coming from the intake gate road flows into the caved goaf and the air heated by the hot waste rocks in the goaf comes out through the latter half of the face. This still constitutes a major heat problem in spite of the introduction of gate and face air coolers. Therefore, in order to establish effective measures to improve the environ- mental conditions, it is essential to obtain information pertaining to the air flow pattern on the face as affected by the goaf conditions and the air flow regulating measures taken at the intake side of the face. Experiments for this purpose were carried out using a coal face model. The model was reduced to a scale of 1110th of the real face measuring 100 m long and 2.2 m high, equipped with self-advancing supports. The model design was also conceived to accomodate eventual modifications of the space of the caved goaf as imposed by the actual conditions.

Jan 1, 1980

By D. W. Gentry

Introduction Until recently, there were many jobs for mineral engineering graduates. Traditionally, minerals-related career paths available to university graduates stem from rather standard offerings in the disciplines of mining, metallurgy, petroleum, geology, geophysical engineering, and mineral economics. Within each discipline, there exists many career opportunities. In fact, until fairly recently, the most difficult decision for most graduates was choosing among all the available alternatives. Unfortunately, this relative state of euphoria changed quickly and dramatically within the minerals sector. Within two or three years, graduates from minerals-related engineering disciplines found it exceedingly difficult - and then almost impossible - to secure employment in the minerals sector upon graduation. At the same time, there were dramatic reductions in production requirements and, ultimately, mine closings. This resulted in massive layoffs and often termination of professional personnel possessing significant and valuable industrial experience. Obviously, this worsened an already bad employment picture for those hoping to begin a career in minerals. Certainly, there is no universal agreement on what the future offers for the US minerals industry or the career opportunities associated with it. However, there are a number of considerations that deserve study by students, faculty, administrators, and industrial personnel before minerals-related career paths are chosen. Where Will the Jobs Be and How Many? Everyone is aware that the minerals industry is very cyclic. It is not surprising then that job opportunities for new graduates also fluctuate. Typically, there is a two-to-four year lag between industry's engineering manpower needs and the academic community's ability to produce this talent. Due to the response lag, there will necessarily be years when supply and demand do not match. Employment Projections It is extremely difficult to anticipate what the key career paths might be within the next few years. Considerable speculation remains with respect to whether activity in the US minerals sector over the short-, intermediate-, and long-term will improve, remain status quo, or further deteriorate. However, some information pertaining to the prospects for career opportunities in mining engineering was offered by Tingley and Ghose (ME, Sept. 1983, p. 1274) from a study performed by Fenvessy and Schwab. Results from this industry-sponsored survey suggest that the US will experience 700 more mining engineers than needed in 1985, 1300 in 1990, and 1800 in the year 2000. These conclusions were based on the assumptions that future graduate levels remain flat and demand increases 3.6% annually. Educators quickly argued that depressed job markets, coupled with university student mobility, would negate the assumption of flat mining graduate levels in the immediate future. Student Mobility Student mobility from one engineering discipline to another is high. This is perhaps best demonstrated by the tremendous growth in programs such as computer engineering and computer science at the expense of enrollments in the more traditional engineering programs. The ability and willingness of students to quickly change engineering disciplines in response to existing and perceived job market demands have created significant student, faculty, and resource dislocations within universities nationwide. This has resulted in problems for university faculty and administrators responsible for effective use of

Jan 2, 1985

There are presently in use many grinding mill control schemes and concepts. This paper presents one operating method of controlling the particle size of the cyclone overflows for proper metallurgical results and controlling the level of the cyclone feed sump and new feed rate to obtain lowest unit cost of finished (ground) material which is usually at the maximum grinding mill throughput. This system stresses simplicity of field instrumentation and control strategy. Both of these factors lead to better operator understanding and acceptance. The low capital investment of this system also makes it more attractive at the Buick Concentrator when compared to other more complicated systems utilizing mass flow measurement and a computer to calculate circulating load and infer particle size. Furthermore, it has the advantage of utilizing an actual measurement for control, rather than a difficult-to-maintain inferred value. There are several reasons for maximizing mill throughput at Buick. The milling rate before automatic control was too low when compared to mill throughput increases planned for the future. Through this new operating system, it appears Buick will not have to make major changes of mill motors and speeds to meet the increased? production rate. Also, since power costs continue to escalate, it is desirable to maximize the throughput to the grinding circuit and reduce overgrinding to achieve a reduction in power cost per ton of ore milled. Presently, 45% of the concentrators' total power is consumed in this grinding circuit.

Jan 1, 1977

By S. S. M. Chan

The design of most underground support systems has largely been based upon empirical rules. This design method has proven to be satisfactory in most cases as witnessed by the number of successfully completed works. However, the adequacy of this approach to the developing technology of ground support systems associated with deep excavation has not been substantiated. In cases where the material has definite time-dependent behavior parameters, rules of past experience become extremely vague and conservative. The Spokane Mining Research Center is currently engaged in extensive research to develop rational design methods for underground structures which will account for the many interacting factors such as in-situ properties of the rock mass, excavation methods, proposed types of support system, construction sequence, and environmental variables. The information presented in this paper pertains to only a segment of the research program,

Jan 1, 1971

By Gordon P. Riddler

IMMM Reporting Code 2001 – Some Developments -General definition of a Competent Person -Rules of Conduct with Guidelines -Table of Generic Terms with Guidelines -More specific to non-metallic minerals -Word ‘ore’ is not used for reserve/resource categories -More definitive on Mineral Exploration Results

Jan 1, 2003

By Howard V. Sears

Prospecting in its modern context means simply the gathering of information on which, to base plans for the utilization of our mineral resources. One prospecting system familiar to T. V. viewers is the pan of the old gold prospector which, while he prospected, could produce the wealth which financed him in his search. Present day geophysical "prospecting" systems, which are based on the real or supposed responses of an ore specimen, to various stimuli finder controlled laboratory conditions, are promoted as means of reducing the cost of prospecting. The universal drawback to all geophysical systems is that they yield "soft" data which are only presumed to be analogous to ore mineralization until they can be calibrated, by conventional prospecting systems, to each actual mineral environment being tested. By this time the system usually is no longer cheap. Since the raw data are too esoteric to be used until interpreted by geophysicists, usually in the light of their own personal theories and experience, the certainty of multiple interpretation is introduced. The concept of prospecting, at St. Joe Minerals Corporation's Viburnum, Fletcher and Brushy Creek mines in the new Missouri Lead Belt, encompasses surface diamond drilling for preliminary exploration, the sub¬sequent development of ore body tonnages and grades and the establishment of mining parameters. The predominantly flat-lying mineralized formation is mined by room and pillar stoping. In an operating mine, jackhammer holer are drilled in backs and bottoms of stopes, and chip samples are taken for assay, concurrent with mining. Thus irregularities in ore bodies or nearby discontinuities are not overlooked which are above or below the general mine

Jan 1, 1971