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By Angelus S. C. Owili-Eger

The past decade has witnessed an unprecendented proliferation of groundwater computer models. Some of these numerical models were developed for the purpose of simulating groundwater movement in mining environments and predicting inflow rates into active mines. However, a general acceptance of these models as routine planning tools by the mining industry has been slow. Until recently, the major use of these models in the industry is by consultants. There are several reasons that have contributed to this situation. Some of these factors - include scarcity or non-existence of an appropriate data base information required for executing these models, the difficulty and costs involved in acquiring data, and the fact that the instructions for using these models are often too involved and time consuming. Today, however, the state-of-the-art technology has been advanced to a level where numerical models can be routinely used to simulate and predict inflow rates into active mining environments. Such environments include highly fractured (longwall) and deforming flow media. Features integrated into these comprehensive and yet easy to use models are double-porosity-pressure, multiphase, and non-darcian flow conditions. This paper reviews the role that computer modeling has played in mining-related operations by presenting several case studies and the state-of-the-art tools currently in use. Included will be some of the practical field applications that have been compiled during the past decade.

Jan 1, 1986

By John A. Ames

Limestone for portland cement must be beneficiated to produce uniform raw material for the kiln. Careful quarrying and selective recovery are factors in this process, but the chief aspects of beneficiation are "in plant" processes, such as crushing and screening, washing, grinding, flotation, and heavy-media separation. Numerous technical and economic problems exist. Detailed studies of the limestone deposit and the stone itself are required for intelligent beneficiation. As used in this paper, beneficiation is defined as the improving of limestone composition so as to produce an economically usable raw material A limestone deposit is defined as a mass of limestone which can be recovered, by quarrying or mining, for sale or for use in a commercially profitable operation. The stone may require elaborate processing, or it may qualify with little or none. Obviously, the "commercially profitable" qualification may change as the economy changes. Potentially commercial deposits may be of much better quality than actually developed deposits, and yet may be denied development for various economic reasons.

Jan 1, 1966

By Lauren W. Choate

Wollastonite, a calcium metasilicate, derives its name from the man who discovered the mineral, Doctor William H. Wollaston, an English scientist. OCCURENCE Occurences of the mineral have been noted in Finland, Switzerland, Russia, Japan, Mexico and in the United States in Texas, California, Arizona, and New York. The only commercial deposit now being exploited is at Willsboro, New York. It is mined and processed by the Cabot Corporation whose home offices are in Boston, Massachusetts.

Jan 1, 1964

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 Frank Littlewood

Research over a period of ten years resulted in the development of an efficient automatic ore feed regulator for mill grinding circuits. The facilities that a large mining company gave the inventor made it possible to develop the control apparatus under actual mill operating conditions. The Littlewood Regulator automatically determines the optimum power input at which a mill should operate, and controls the rate of ore feed to maintain this optimum power for any predetermined operating conditions. It is to be noted that the optimum power varies with many factors such as ball, rod, and mill liner wear, therefore the regulator is designed to automaticall keep itself properly calibrated. To efficiently control the rate of ore feed of a mill grinding circuit the regulator analyzes and interprets all power changes of the mill motor. The critical electrical measurements for this type of control are made possible by a patented device that has the ability to detect and integrate minute changes in power. In ball mill operation the small but significant changes in power serve to select the rate of ore feed in accordance with the rate at which ore accumulation takes place within the mill, and in rod mill operation they serve to select the rate of ore feed in accordance with the degree of rod spread.

Jan 1, 1970

By Eugene L. Foster, Gilbert L. Butler

The successful demonstration of a precast segmented concrete liner in the Lexington Market Section of the Baltimore Regional Rapid Transit System (BRRTS) is an important step forward in our continuing efforts to control tunneling costs in the USA. In addition to its contribution to specific savings in future tunnels, this demonstration project has taught other lessons about the U.S. tunneling industry and about the process of "mainlining" new and improved technology into that industry. This paper will present an overview of the Lexington Market Demonstration Project from its beginnings to the present time. In addition, it will discuss other implications which have an important bearing on the extent to which tunnels will be used in future transportation systems in the USA. THE HISTORY Precast segmented concrete tunnel liners are not new. An unbolted version was reportedly used in New York City in the 1930's. The modern bolted configuration has been in use in foreign countries for more than 15 years. Indeed, consideration of the use of precast bolted segments below the water table in the USA dates back to the BART system in San Francisco in the 1960's. At that time, they were evaluated and it was concluded that the state of the art would not allow segments to be precast to the required tolerances. A secondary grinding operation would be required if water-tightness was to be assured, making them economically non-competitive with steel. Based

Jan 1, 1981

By Jay Hilary Kelley

A ventilation system is described using dual aircourses: one zone occupied by working personnel, the other at the active working face. The two zones are separated by a partition or Shroud. The occupied zone to the rear of the face zone is ventilated adequately but with considerably less air because little gas, dust, or fumes are present. The face excavating zone is sealed and maintained at slightly more negative pressure preventing dust and gas generating from within to escape. Explosive mixtures within the face zone is rendered non-explosive by the introduction of inert gas therein. Each zone is vented separately to the outside of the mine. Because less total quantity of air is required for human breathing, etc, the total ventilation system can be drastically reduced in tan capacity, development entries, and air shafts, -- a great savings in costs.

Jan 1, 1991

By L. B. Phelps

Industrial mineral production is basic to life in these United States. Production techniques of these minerals are part and parcel of the training that mining engineering educators must, and do, impart to their students. This paper deals with the basic mining engineering program required by all accredited engineering schools and the specific way the Pennsylvania Scare University presents and builds upon them. The manner in which these concepts provide the student with the necessary tools to function as a mining engineer in me realm of industrial minerals extraction is discussed.

Jan 1, 1981

By N. Magdalinovic

This paper analyzes the basic elements important for sustainable development in the sphere of metal mineral raw materials and offers one of the possible ways of defining the index of sustainable development.

Jan 1, 2007

By Mark R. Stanton

Geochemical and mineralogical analyses of 46 samples from six drill cores in the Mayday mine pile near Silverton, Colorado, demonstrate wide variability in trace metal contents with spatial location. This variability results from the original geochemical composition of mined rocks, mixing of ore and non- ore rocks during emplacement of the pile, and weathering since rocks were placed in the pile. Weathering reactions are controlled by factors such as pile thickness (depth), water availability, microbial activity, and mineral dissolution and formation kinetics. These factors result in variable redistributions of trace metals from primary (ore) to secondary (weathering products) minerals within each core.

Jan 1, 2000

By Kalman N. Isaacs

Aerial photography is a recognized and integral part of the search for petroleum and for the metallic ores, but its application lags seriously; in the search for the industrial minerals This is, in all probability, a result of the relatively stringent economics of the various industrial mineral industries. The oil and mining companies (particularly the oil companies) can afford generous exploration budgets and thus can experiment with unorthodox approaches such as photogeology. The industrial mineral industry is more restricted, and up to now has relied on less sophisticated methods of exploration. The industrial minerals have been generally defined as those materials extracted from the earth that are neither metals, metallic ores, fuels, nor ground water. Any group chat must be defined in such a negative manner, by citing the things that they do not include, must in themselves be extremely diverse in character. This is truly the case for the industrial minerals; the full list of industrial minerals is incredibly long and tends to increase year by year.

Jan 1, 1964

By J. P. Fitzgerald

This paper is an accumulation of information on the geology, mineralogy and mining of the Hectorite clay deposit owned by NL Chemicals (U.S.A.), Inc. The mine is located in San Bernardino County, California approximately 35 miles east of Barstow and 1-1/2 miles south of U.S. Highway 40. The region is known as the Mojave Block which is a region bound by the San Andreas fault zone to the southeast and the Garlock fault zone to the North. The faults of both zones are active, vertical faults along which movements are mainly horizontal. Most of the faults within the Mojave Block are high angle faults which trend northwest. They are considered part of the San Andreas fault system and are a result of the right- lateral movement characteristic of this system. The east-trending faults are also high angle faults, along which movement has displaced rock units vertically. Manix fault is the only mapped fault that shows evidence of left slip which is characteristic of the Garlock sys tem to the North.

Jan 1, 1986

By T. Yun

The process automation of coal production is one of the important component parts for achieving the modernization of coal industry. To realize the coal mining process automation serves the significant, function of increasing productivity, improving the quality control of raw coal, making efficient use of mineral resources, saving energy and is of great importance in enhancing the safe operation and improving the labour conditions as well.

Jan 1, 1989

By C. E. Jordan, B. J. Scheiner

The Bureau of Mines has developed a continuous ultrasonic flotation cell for the recovery of Florida phosphate ore. Within a small mixing chamber near the bottom of the flotation cell, an ultrasonic probe agitates an injected mixture of air, water, and phosphate ore and breaks the air into fine bubbles. Phosphate particles are preferentially attached to these fine bubbles and floated in the main chamber of the flotation cell. Over 94 pct of the phosphate was recovered, resulting in a 30 pct P205 concentrate. The ultrasonic energy consumption was less than 7 kW.h/mt of phosphate ore.

Jan 1, 1989

By R. L. Grayson, N. P. Reddy, D. A. Kinzler, S. Yuan, W. R. Myers, R. A. Wells

An examination was conducted on the impact of roof conditions and the mining cycle in determining a representative respirable mass concentration at the mid-shearer location on a longwall panel. Multiple personal gravimetric dust samplers, operated at a flow rate of 2.0 lpm, were used at different locations along the face to isolate the concentrations and variances associated with good and bad roof conditions under both the cutting and cleaning mode of operation. The number of samples needed to estimate the population variance at a given confidence level was analyzed. In addition, the statistical analysis showed that the coefficient of variation of dust concentrations at different locations and under different conditions ranged from 0.185 to 0.475, with an average value of 0.283. The estimates of the average dust concentration for a shift and the variance of the dust concentrations were calculated. A total of 48 data points were available for an [a x b] factorial ANOVA (analysis of variance). The estimates of the variance components were determined. The results from F-tests indicated that both the roof conditions and mining operations had a significant effect on the respirable dust concentration. There was no significant interaction effect between mining operations and roof conditions. In conclusion, this study shows that not only should sampling and analytical errors be considered in determining the required number of samples for a good estimate of the long-range exposures of miners, but also fluctuations of concentrations due to mining operations and geological conditions should be taken into account.

Jan 1, 1991

By Julian S. Edwards, C. Frederick C. Pearson, Sevket Durucan

Information gained at the site investigation stage of the Carsington aqueduct project led the designers to suspect that methane might be encountered during tunnelling and therefore gas detection techniques, including emergency shutdown systems, were introduced. After construction, on completion of the excavation and lining of the tunnels, a survey showed that methane was entering the aqueduct dissolved in infiltrating groundwater. General body air concentrations were very low but on closure methane concentrations rose rapidly within the aqueduct. A research project has now been initiated to investigate the mechanism of methane generation and entry rate into the system, the results of which are being taken into account in the preparation of future operating procedures.

Jan 1, 1989

By Robert C. Sutter

In 1958, it became obvious to some of us in the solution mining business that there were certain problems in connection with our sodium chloride brining operations which were industry- wide. These were the types of problems which, while they were important to the safe and economical operation of our salt brining operations, were not such that their solutions would give an individual company a great competitive advantage over his competitor; and since they involve the safe and efficient mining of a natural resource, it was obvious that the answers would, in any event, be shared industry-wide. Since we were dealing with underground solution mining and, consequently, unseen and remotely controlled operations, the problems are formidable and the solutions difficult. While all of us were doing work to improve our operations, none of us could justify the expenditures necessary for basic research in these areas. Consequently, the idea was conceived of research sponsored by many companies with the same problems. In 1960, 11 companies entered into a' formal agreement to jointly support research on a specific problem of sodium chloride solution mining. The project to be undertaken was the development of a method for measuring the size and extent of underground solution cavities in sedimentary salt beds. It was agreed that all research was to be performed by independent research organizations. A part-time consultant or administrator was retained to administer the research contracts and to provide technical advice.

Jan 1, 1966

By Carl L. Morris

This short dissertation concerning "what the client expects from the engineer" is directed mainly at the design and construction of metallic ore concentration or beneficiation plants. However, practically the same conditions apply to the design and construction of cement and lime manufacturing facilities, with the exception that the latter facilities reflect the client's and engineer's concepts of customer service and in some cases reflect promotional considerations for the product manufactured and distributed. The client expects his engineering contractor to contribute in an efficient, cooperative, and economical manner current industry-wide know-how and experience to the specific project under consideration through the client's organization

Jan 1, 1969

By Julián Ortiz C., Clayton V. Deutsch

Indicator simulation allows specification of different continuity of high and low values through the use of grade thresholds. The sequential implementation of indicator simulation has been widely used, but the problem of order relation deviations remains a significant drawback. A new procedure for "Hierarchical Indicator Simulation" is introduced that avoids order relations and offers greater flexibility than the conventional sequential approach. The new implementation simulates all locations at the largest threshold and then considers decreasing thresholds in turn. All nodes with grades that are above the previous threshold are excluded from the domain of the current threshold and therefore, they are not used as conditioning data. The probability of being above or below the threshold is calculated using simple indicator kriging using all conditioning data in the domain, thus the covariance structure is preserved. The theoretical framework of this new approach is fully developed. Practical implementation details are discussed. Application to a copper deposit shows the advantages and drawbacks of the method. Finally, the possibility of incorporating multiple-point statistics is discussed.

Jan 1, 2002

By Legett Garrett

Texas Utilities Generating Company (TUGCo) surface mines lignite for use as a boiler fuel at mine mouth generation stations. Currently, the annual lignite production requirement of approximately 28 million tons necessitates mining across approximately 1,600 surface acres each year. The mining operations, located in Freestone, Panola, Titus, and Hopkins counties, Texas, have drastically disturbed some 13,000 surface acres to depths of up to 110 feet since initial startup in 1971. The TUGCo mining philosophy, a commitment made prior to initiation of mining operations and prior to any mining regulations, includes a return of mined-out land to private ownership in the most useful state possible. In the areas of TUGCo operations, the local economies are based upon agricultural production. Historic land use surveys have typically shown a trend from row crop production to pastureland for cattle production. During the 1960?s, the percentage of acreage devoted to row crop production approached zero with respect to the total acreage devoted to agriculture. TUGCo reclamation operations have therefore emphasized restoration of land to a state that is favorable to cattle production

Jan 1, 1982