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By Earl R. White

In 1950 Kaiser Steel Corporation acquired control of the Utah Fuel Company, a pioneer Utah coal concern owning large reserves of high volatile coking coal near Sunnyside, Utah. The mines at Sunnyside have been producing high quality coking coal since the late 1890's. Kaiser Steel acquired the coal deposits at Sunnyside in order to supply the necessary coke for its steel plant at Fontana, California. The Sunnyside coal deposits are made up of two mineable beds, the upper and lower Sunnyside seams. Both seams outcrop along the southward facing escarpment of the Book Cliffs. The coal seams dip under the massive sandstones of the Book Cliffs to the northeast at 5 to 22 pct., with the steepest-part being near the outcrop. Mining at Sunnyside up to 1961 had been carried on with room and pillar methods. The deep cover and rotten roof conditions, along with the need of increased tonnage, required a change of mining technique. Numerous ideas were presented, discussed, and economically analyzed. Several people involved in these discussions, with the aid of W.W. II, had been introduced to the European methods of coal mining, namely the longwall technique. The European mines had long been plagued with near similar conditions as those at Sunnyside, particularly the deep cover problem. The longwall method seemed to be working very well under these conditions, and with the extensive studies given longwalling by the Kaiser Steel mining officials, it was decided to give longwalling a try.

Jan 1, 1976

By Thomas P. Goslin

T e mechanization of industry to reduce labor costs and to improve product quality is affecting he scale industry as it has affected many other industries. With increased emphasis on higher production rates many operators are experiencing difficulty in overcoming production problems where weight is a factor. Unfortunately, the scale industry has not shown the development over the last twenty-five years that other instrument industries have. For centuries the balance scale has been the standard and the workhorse of most weighing operations. In recent years considerable effort has been applied to designs to make balance scales more acceptable to industries employing automatic or semi-automatic processes. For the most part the designers have not attempted to replace the basic scale but toautomate functions of material handling and human judgement. Modern dump scales, for example, will accept material from a conveyor until a preset amount of material is on the scale, At this time the scale turns off the conveyor, dumps the load of material and repeats the operation with any desired timing. These improvements have helped industry. Even the scale observer has been replaced with devices which observe the scale reading and operate on weighed objects according to their weights. In spite of' the application of automation to the material handling, the balance scale has not been completely satisfactory. One reason for this is fairly evident when one considers the construction of the scales. Inherently, they are slow devices because of the inertia of the beams. The beam scale, primarily a static measuring device, is at the best limited to slow dynamic measurements.

Jan 1, 1958

By Charles C. L. Smith

A review and comparison is made of the circuitry utilized for dc crane control systems. Anti-parallel three phase full wave thyristor bridges for dc motor reversing and speed control are compared with a single three phase full wave thyristor bridge for speed control and either contactor or static switching for reversing control to obtain complete four quadrant operation for crane material handling. In recent years the Harnischfeger Corporation has developed a solid state adjustable voltage control system to control the speed and direction of dc motors for crane applications and handling materia1.1 Shunt wound dc motors are utilized and speed is controlled in the motor base speed operating region at constant torque by a thyristor, silicon controlled rectifier (SCR), adjust- able armature voltage supply. The three phase thyristor bridge is the power controlling element of the dc adjustable voltage control. ELECTROTORQUE is the Harnischfeger Corporation registered trade name for this type of drive system. By controlling the gating signals or firing pulses to the thyristor bridge SCR's the dc output voltage can be varied over a wide range. This range is limited only by the magnitude of the ac applied voltage. To obtain operation of the motor in both directions two thristor bridges are connected in an anti-parallel arrangement. A typical schematic for two anti-parallel connected three phase SCR bridges is shown in Figure 1.

Jan 1, 1973

By J. Patrick Powers

In tunneling through water-bearing formations, the expense of controlling the water can have a major impact on overall project cost. The author has seen the cost of an eight-foot, finished sewer tunnel rise from under $500 per foot to over $1,000 when a water problem, anticipated as modest, became severe. There is need for greater professionalism in the approach to groundwater control. The days of the forked stick should be behind us. The basic technology exists. Its application is not yet widespread. This paper discusses predrainage; that is, the lowering of water in advance of tunnel excavation. Both free air and compressed air tunnels are considered. Examples from recent tunnel projects are described. SPECIAL NATURE OF TUNNEL DEWATERING Tunneling is unlike other excavations below the water table in a number of significant ways. The tunnel excavation is always on the critical path; if production slows or stops, there is no other work for the heading crews, no other work to carry the cost of service crews and job overhead. The dewatering commitment must be made well in advance. Construction of wells, and pumping down take time. After the heading reaches a trouble area, time is not available

Jan 1, 1997

By I. S. Parrish

This article offers one of the infrequent looks at Chinese mining. It includes a brief review by Parrish of a tungsten symposium held there and his comments on and impressions of the mines he visited. In early Oct. 1981, a Symposium on the Geology of Tungsten was held in the Peoples Republic of China. There were approximately 100 participants. Half of them were Chinese. The remainder included representatives of the United Nations, geologists from other nations in Southeast Asia, and 10 invited specialists from other countries. The invited guests included K.F.G. Hosking of the Camborne School of Mines, United Kingdom; C.S. Hutchinson of the University of Malaysia; K. Mattson of LKAB Int. AB, Sweden; T. Kwak of Latrobe University, Australia; K. Sato and S. Ishihara of the Geological Survey of Japan; M. Clarke of the Department of Mineral Resources, Indonesia; P. Bateman of the US Geological Survey; and the author. R. Horsnail of Amax was also invited but was unable to attend because of delayed visa clearance. The meeting was noteworthy because the Chinese were presenting more than half the papers. In addition, following the formal session, everyone was taken to the famed Jiangxi tungsten district and toured four mines there. Organization and Background The idea for a symposium on tungsten geology was brought up in late 1979 during a visit to China by the Economic and Social Commission for Asia and the Pacific (ESCAP) and, in particular, by members of the Regional Mineral Resources Development Centre (RMRDC) of the United Nations. Discussions continued and in the spring of 1981 invitations were sent to selected geologists throughout the world. China's Ministry of Geology handled arrangements, scheduling, and logistics. Travel to China and all correspondence before the symposium were coordinated by the Bandung, Indonesia Bureau of RMRDC. All costs in China were met by the Peoples Republic of China. Airfares and "per diem" enroute for participants were paid by respective governments, sponsors, or individuals. On Oct. 10, visiting participants entered China from Hong Kong. The author and a few others traveled by train to Guangzhou (Canton). Most of the group flew in the next day. The entire group was then taken to Nanchang, traveling by sleeper train and arriving on Oct. 11. The symposium group stayed at the Kiangsi Hotel, where the meetings were held. Meetings Oct. 11 was a day of orientation and rest. The group was taken to an art museum and treated to a Chinese opera movie. The formal meetings began on Monday, Oct. 12. Simultaneous translations aided presentations, though more than half the Chinese speakers delivered their talks in English. The acoustics and sound system were excellent, and the Chinese provided 35-mm and overhead projectors. There was no screen, however, and the yellow, painted wall that was used detracted from projection clarity. In general, the Chinese papers were detailed, thoughtful, and professional. Some, naturally, were stronger than others. Taking them as a unit, one derives the following sequence to the Chinese approach to tungsten exploration: (1) Geologic investigations with mapping at a scale of 1:200,000 accompanied by only minor geochemical or geophysical work. (2) Geophysical investigation with regional gravity and magnetic surveys directed toward identifying deep, tectonic systems and seeking granites in thick, crustal environments. (3) Geochemical sampling in-

Jan 6, 1982

By A. Anani, K. Awuah-Offei

"Accounting for changing duty cycles in equipment matching maximizes equipment utilization and productivity. The objective of this study is to investigate if the optimal number of shuttle cars for a particular panel width is optimal in different segments of the panel. In this study, discrete event simulation (DES) is used to determine the optimal number of cars that maximizes productivity in each segment. Data from a real-life mine is used to validate the model. The study shows that the optimal number of cars for the entire panel may not be optimal for some of the defined segments. INTRODUCTION Fleet optimization is important for efficient mine management. Deploying the optimal fleet minimizes the capital and operating expenditure for particular operating conditions and production targets. In an operating mine, with an already existing fleet, deploying the optimal fleet maximizes productivity or minimizes production cost with the available resources. Hence, a lot of research has focused on how to determine the optimal fleet size for a mining operation, given particular operating conditions. Mine managers and engineers have successfully used discrete event simulation (DES) to determine the optimal fleet size in mines (Michalakopoulos, Roumpos, Galetakis, & Panagiotou, 2015; Awuah-Offei, Osei, & Askari-Nasab, 2011; Ben-Awuah, Kalantari, Pourrahimian, & Askari-Nasab, 2010; Govinda Raj, Vardhan, & Rao, 2009; Yuriy & Vayenas, 2008; Kwame Awuah-Offei, Temeng, & Al-Hassan, 2003). In most cases, the published work on this topic involves determining the number of hauling units to be matched to a loading unit. Many of these examples involve truck-shovel optimization. There are, however, some underground mining examples. For instance, we recently concluded work that involves fleet optimization in underground room and pillar (R&P) coal mining (Awuah-Offei & Anani, 2015). Generally, when DES is used in fleet optimization it involves three steps: (1) Build a valid model of the mining system capable of predicting the required outputs with varying fleet composition; (2) Design and conduct experiments that vary the fleet composition across all feasible options; and (3) Determine the optimal fleet based on the results of the simulation experiments. A major decision in the first step is which outputs should be modeled. Some examples in the literature include productivity, unit cost, loader utilization, queue length, and hauler waiting times (Awuah-Offei et al., 2011; Govinda Raj et al., 2009; Kwame Awuah-Offei et al., 2003). Often, more than one of these outputs are simulated and considered as the objective function of the optimization."

Jan 1, 2016

By L. W. Saperstein

One of the most critical skills developed by underground coal miners is the ability to interpret natural warning signals in terms of impending roof failure. A miner receives a variety of signals which can be called warning and which can be classed broadly by sense: aural, visual, and tactile. This paper concentrates on those signals which are airborne and audible. These signals are creaks, cracks, pops, groans, snaps, booms, tears, rips, and other assorted pulses which emanate from the roof strata, coal pillars, and artificial support in response to the stresses induced by the mine opening. These pulses are sometimes referred to as "talk". Although it is clear that miners rely on roof talk to assess the roof's stability, it is not clear of what roof talk is composed. It has been described in a variety of figurative ways, but has not been scientifically characterized. As will be shown shortly, the purpose of this research is very specific. The ramifications, however, are very broad, and are, indeed, still being followed.

Jan 1, 1974

By George M. Anderson

The extraction of industrial minerals is usually confined to relatively small mining operations. The recent COSMAR (Committee on Surface Mining and Reclamation) report found that 93% of all mines in the United States were of the small unit variety. Also, of the total number of mines in the U.S. (15,279) 96% were in the industrial minerals (non-metals excluding coal) category. To break it down further, 86% were sand and gravel, and crushed stone operations. Therefore, we are talking about a very large number of small mining operations. If these small miners can afford to hire a college graduate, what kind of training should this person have beyond the normal mining engineering curriculum to best serve the problems that he or she will encounter?

Jan 1, 1981

By J. D. Cooper

Previous research developed guide- lines to restrict the placement of air velocity sensors to areas of Low turbulence in underground nines. Even though these guidelines are theoretically correct, and may be easy to follow in underground coal mines, their application in small underground metal mines is difficult. As a result, study was undertaken at the Colorado School of Mines Experimental Mine to determine if an air velocity sensor could be placed in other locations with acceptable results. It was found chat by applying a variable calibration function to correct for changes in amounts of turbulence, instead of the previously used calibration factor multiplication, the sensor could be used successfully in areas of moderate turbulence.

Jan 1, 1984

By R. A. Lowe

The low-shear viscosity of kaolin slurries is one of the principal characteristics that determines whether the clay can be utilized for paper and ceramic applications. In this work, causes of poor low-shear viscosity and methods of improving rheology have been investigated. The presence of fine-grained smectite impurities within the kaolin was shown to detrimentally affect the low-shear rheology of slurries produced from these clays. It was also shown that mechanically working (i.e., pugging) a crude kaolin followed by desliming to remove these impurities can reduce the low-shear viscosity.

Jan 1, 1998

By B. J. Scheiner

The Federal Bureau of Mines has developed a chlorine-oxygen leaching technique for the recovery of metal values from lead-zinc sulfide concentrates. Lead, zinc, copper, cadmium, and silver extractions are in the 95- to 99.9-percent range. During leaching, the zinc, copper, cadmium, and silver are solubilized as metal chlorides, and lead is converted to insoluble lead sulfate. The iron contained in the concentrate is converted to insoluble iron oxide, and a majority of the sulfide is converted to elemental sulfur Minor metals such as copper, cadmium, and silver are recovered by precipitation with zinc dust. Zinc is then recovered from the purified zinc chloride solution by evaporation to dryness; the lead is recovered from the leach residue by brine leaching and crystallization to produce lead chloride. Recovery of zinc and lead metals by fused-salt electrolysis of the chlorides is being studied separately.

Jan 1, 1975

By E. B. Thorn

The production of portland cement requires that four basic elements -- calcium, silica, alumina and iron -- be ground to a fine powder, homogenized, and fed to the pyroprocessing unit, where it is burned to a cement clinker. The raw material must either be ground wet in a slurry form or dried and ground to a dry powder, with a fineness of approximately 85% passing the 200 M screen. According to the Portland Association's Plant Information Summary, approximately 38% of the U.S. capacity is ground wet and 62% ground dry. The following data is taken from the Portland Cement Association's 1981 Energy Survey: [Million BTU/Ton kW h/Ton Wet Process Plants 5.86 138 Long Dry Process Plants 4.97 123 Dry Preheater Plants 4.03 157 ]

Jan 1, 1984

By D. Diggins

Experimental apparatus for the determination of powder wettability is described. The principle of the technique is based on the measurement of the equilibrium capillary pressure in a packed bed of particles. Both the macroscopic solid-solution-vapour contact angle, e, and the specific surface area, A(m2g-1), of the powder, can be obtained. Experiments on angular quartz particles have been performed. A wide range of situations have been covered: hydrophobic and hydrophobic particles wetted with water, a variety of organic liquids and solutions of surfactants. The results show that reliable and reproducible values for 0 and A for angular and relatively coarse powders can be obtained with the proposed equipment for advancing liquid fronts in the absence of soluble surfactants. In the latter case and for receding liquid fronts in general, only qualitative trends have been obtained.

Jan 1, 1992

By Charles E. Michener

This paper deals with the occurrence of basic and ultrabasic rocks and their relationship in space and time to major structures of the earth. In order to introduce the paper properly, I must go back a little and try to put the subject in perspective. In the brief time that geology has been a scientific occupation, ore deposits have been grouped and classified in various ways depending on the theories that happened to be popular at the time. Some of the early scientists said that ore came from fire, other schools argued that ore originated from water. Then came the lateral secretionists and in later years the hydrothermalists led by the Lindgren school and the latter has largely been accepted as the modern concept of ore deposits. It now seems apparent that the hydrothermal school is being seriously challenged by other schools of thought. It also seems that we have reached the point where we should be willing to admit that we do not really know in most cases how the ore got to its present position. However, for practical purposes, we can classify ore deposits as to the environment in which they do occur. This is not difficult and gives the field geologist and the mining engineer something to work with and to believe in, and it gives them a basis for carrying out their field work. On the screen, Figure 1, there is a classification of ore deposits based on the environment. Under each classification is listed the more prominent metals which are characteristic of that

Jan 1, 1971

By F. H. Deily

The petroleum industry has developed and utilized many aspects of rock mechanics, both in its search for petroleum and in its drilling and production operations. Geological exploration activities have been improved by knowledge of earth tectonic forces. Better understanding of seismic wave motion has contributed to a more accurate interpretation of geophysical data. Drilling activities have benefited from basic knowledge of rock strength behavior under in situ conditions. Production has been significantly increased through stimulation techniques, such as hydraulic fracturing. The ability of rock mechanics work to contribute to future petroleum activities will depend upon the development of knowledge of rock properties under greater depths and at higher pressures and temperatures.

Jan 1, 1969

This paper presents a method for evaluating the economic feasibility of solution mining a hypothetical uranium roll-front deposit. It is assumed the wellfield will be operated in a prudent manner and that leaching tests were performed in depth in both lab and field (push-pull) prior to startup. Leach test results are reduced to two important parameters and used as the basis for solution mining a wellfield. This case study assumes a 10 mil- lion-lb uranium deposit with 40 possible small wellfields; four are kept in operation simultaneously until the deposit is depleted. The wellfields have different ore reserves and grades, lixiviant circulation rates, leach rates, and peak concentrations, and thus the daily uranium production will vary. Daily production is used to assess the profitability of a particular lixiviant and the mode of well- field operation in light of realistic market price estimates. The mathematical procedure is simple and straightforward, based on reasonable in-situ leaching relationships as well as accepted accounting practices.

Jan 1, 1985

By Gerrit V. R. Goodman, Edward F. Divers, Charles D. Taylor

Future mining systems will possess the ability to cut from crosscut to crosscut where advances could exceed 30.5 m (100ft). However, limitations arise when ventilating such mining systems. In deep advance mining, there will be no workers at the face to manually advance ventilation tubing or curtain. Additionally, traditional methods provide no means for maintaining face ventilation after the miner backs out. Problems such as these have suggested the need for innovative ventilation methods compatible with deep advance mining systems. The Bureau of Mines is currently considering a number of innovative ventilation schemes. One such method is the use of a jet fan to ventilate a deep cut. A jet fan is simply a freestanding fan using little or no ducting to direct the ventilation flow. Previous testing in large metal-nonmetal mine entries showed that jet fans provided adequate face ventilation for deep advances in large headings. Current testing will determine the application of jet fans in ventilating smaller coal mine entries. Another approach considered compatible with deep advance mining will use either exhausting or blowing tubing that can be remotely extended from crosscut to crosscut. During the mining cycle, such a device would extend automatically as the miner sumps into the face. The Bureau of Mines is considering several different operating designs using this tubing.

Jan 1, 1991

By Daniel T. Hegyan

The employment of continuous rotary vacuum disc filters to filter refuse from the fine coal washing circuits has been increasing as it has become more important to close the water circuits and eliminate sludge holding ponds. This paper will discuss our past experience filtering refuse, effects of solids concentration in the filter feed, use of polymer flocculation aids, effect of flocculation devices, and effects of particle size and ash content on the filtration rate. Detailed tests were performed on existing installations utilizing coal refuse filters to determine optimum flocculant dosage, solids concentration, and disc rotation speed to form a dischargeable cake. Information was also obtained showing effect of flocculant addition on the moisture of the filter cake. Our test work has shown that the continuous filtration dry cake rates for fine coal refuse correlates very well with the data developed and presented by Silverblatt and Dahlstrom1 except that the curves have moved up the scale by use of polymer flocculant additions. These polymers were not available at that writing. Finally, our tests also confirmed the general premise stated by S. K. Mishra2 that controlled additions of polymer flocculants will reduce filter refuse cake moistures somewhat.

Jan 1, 1974

By T. Cantwell

Techniques useful in operations, analysis are applied to the problem of planning an exploration program. The model used treats mineral exploration as a Markov process, and maximization of gain is the criteria determining the optimum program. The mathematical description of the model and the optimization are first worked out. Application of the mathematics to several simple examples is given. Finally, comparison of the data necessary to use this operations analysis with the available data shows that the method can only be a guide to planning an exploration program.

Jan 1, 1962

By W. Irwin

Global warming hitherto viewed as a distant threat to the environment, is now the subject of fierce goo-political debate. The debate centres around the time frame required to achieve environmental compliance, and the cost implications of meeting that objective. Since coal is the fuel of choice for power generation, the priority objective of energy producers is the pursuit of environmental protection measures that allow coal to be burned without any attendant negative impact on the environment. From an environmental point of view, public attention is today firmly focused on the impact that all industrial activity has on the environment, and coal is singled out from other fossil fuels as being the product of an inefficient smokestack industry. Despite coal's poor public image it is unrealistic to suggest as some do, that use of this fossil fuel as a primary energy source should be drastically curtailed. Coal which already generates about 35% of the world's electricity is continuing to increase its share of this rapidly expanding market, and to argue against its use is flying in the face of reality. However, changes are required in the way coal is used in some of the new clean coal technologies, since many include advanced methods of combustion. Indeed changes in the way coal is used is a vital link to the future of coal as a primary source of energy, and increased coal utilization will be directly linked to changes in its use. Discussion of various issues that affect coal utilization are the focus of this paper.

Jan 1, 1998