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By Keith K. Griffiths

Computers are a valuable tool to the aggregate industry and should not be overlooked. The selection of proper mechanical components is necessary. Merely the addition of a computer to operate a mechanical system will not guarantee that the system will work. Material delivery by rail or truck for stock-piling and intra-plant material transfer can be accurately supervised by automation with simplified controls for the layman to use. There are mechanical problems that occur in material blending and load-out systems when such a system is automated. Such things as material flow, bridging, stockpiling methods, overloading of equipment and safety must be considered. How these problems can be overcome by proper selection of compatible mechanical and computer equipment will be discussed. Also, there are many individual material circuits in a plant that can be computerized at a nominal cost. This type of computer installation will not necessarily result in increased production, but it will produce greater efficiency in manpower. These small computers, binary counters, memory circuits and other devices and their application to the aggregate industry will also be presented. A careful evaluation of the mechanical and computer inter-relationship by someone understanding both "Rocks and Electronics" is essential to proper handling of material by computers. Computers for the mining industry may be either digital or analog computers. Unless the computer is to control some type of chemical process, such as a cement plant, the, analog computer is not required and the digital computer' will be quite adequate and less expensive.

Jan 1, 1967

By Ray A. Rothrock

The in situ mining of uranium is the process whereby chemical lixiviant is injected by means of wells into, and flowed through, an ore body. The lixiviant reacts with uranium which has been previously oxidized making the uranium soluble. The solution is then brought to the surface by means of producing wells. In situ mining disturbs the ground-water quality in the immediate area. Since ground water is a natural resource used by man, care must be taken not to allow the lixiviant to escape the local mining area. Also, when the ore body is mined out, the area should be restored to as near its original state as is reasonably achievable. The return of ground-water quality to its original state can occur naturally over a long period of time or be enhanced using appropriate technological means.

Jan 1, 1981

By C. J. Konya, A. Konya

"Presplitting is a form of blasting that when executed properly will create a smooth wall that will minimize secondary conditioning. In recent years, presplitting has become a popular technique to be used in both the mining and construction industry, however, presplitting fails on many occasions because of ‘geologic conditions’. This is typically because of improper explosive loads consisting of overloading and underloading blastholes. In this paper the authors introduce new factors such as a presplit factor which varies for different rock types, selection criteria for the spacing of presplits, the optimization of explosive load, as well as prediction methods for the environmental affects for the technique of Precision Presplitting. BACKGROUND Methods of controlled blasting in which a smooth, stable wall could be blasted have been an important consideration since blasting in mining and construction has begun. How can one use an explosive, with its massive energy and power, to break a non-homogenous rock without causing backbreak, poor walls, or deviations in the wall over large distances? The blasting industry has known for a long time that blasting ‘high benches’ would result in better walls and less backbreak. However, this was not a sufficiently controlled technique for critical projects, such as the Niagara Power Plant. This was one of the main challenges Hercules Powder faced when they began the project. In order to achieve this, they used a new tool in the explosive engineer’s toolkit, presplitting. The presplitting done on the Niagara Power Project utilized 1 ½” x 8” (38mm x 203mm) 40% gelatin dynamite in 2 ½” (63.5) diameter boreholes. This was done on multiple levels with benches between 12 feet to 52 feet (3.6m to 15.8m) with a total powder factor of 0.75 pounds/cubic yard (0.45 kg/m3). The spacing on these holes ranged between 18 inches to 24 inches (0.46m to 0.61m), center to center (Langfors & Kihlstrom, 1973). The strange aspect of this project was that this “lightly loaded” closely spaced row was fired before the production blast, yet this project produced some of the best walls seen at that time directly from blasting. In today’s blasting industry, presplitting is a more common way to produce smooth, stable high-walls for both the construction and the mining industry. Today, explosive loads for traditional presplitting is generally measured in pounds per foot (kilograms per meter) and typically ranges from 0.30 lb. /ft. to 0.5 lb. /ft. (0.45 kg/m to 0.75 kg/m). MECHANICS OF PRESPLITTING When analyzing a blasting process like the Niagara Project, many wonder how did that work when normally confining a charge would cause cratering and increased backbreak. Since then, presplitting mechanics have been studied extensively. It has been shown in many models that presplitting is not achieve through the collision of shockwave, but by gas pressure in the boreholes. In addition to models and finite element simulations, this has been proven full scale using Pyrodex, a propellant, to create a presplit plane with no shock wave present (Konya, Dean Barrett, & Smith Jr, Presplitting Granite Using Pyrodex, A Propellant, 1986)."

Jan 1, 2017

By John A. Wolfe

The concepts of sea floor spreading and plate tectonics provide more logical explanations of some geologic processes than were possible a few years ago. I plan to premise my discussion of the regional features of Philippine porphyry copper deposits on this tectonic basis, recognizing that parts of the picture can be explained in other ways, but in the belief that this is the best explanation of the whole. The sequence of events which results in the formation of Porphyry deposits (Figure 1) can be summarized as the result of collision of crustal plates, subduction of the oceanic plate, emplacement of a serpentine ultrabasic diapir, formation of a dioritic magma at depths of 300 to 500 km, rise of the magma to a sub crustal or intra-crustal chamber, eruption of andesitic volcanoes, emplacement of diorite or differentiation of the magma into more acidic products, multiple intrusion of hypabyssal rocks and hydro-

Jan 1, 1973

By John P. Anderle

A tectonically disturbed sequence of Mississippian age evaporites expressing a 5 milligal negative gravity anomaly near Sussex in southeastern New Brunswick, Canada, was investigated by a program of drilling, geologic and geophysical work over the past 27 months. Seventeen of twenty-one drill holes have penetrated 10 to 140 feet of potash mineralization in a salt sequence underlying 2 000 to 3 000 feet of arenaceous, conformable red beds, also of Mississippian age. Bromine and borate studies, lithological characteristics and geophysics, have facilitated improved understanding of the salt structure. The salt sequence has been affected by f1owage which has resulted in both major and minor folding. In the more disturbed areas, the potash interval was extensively subterraneally eroded at the upper anhydrite-salt contact.

Jan 1, 1978

General. Data for the operating information given in the 15 tables in this chapter was obtained from voluminous questionnaires sent to over 100 operating companies in 1972. There has been a considera¬ble change since then in supply and power costs and many companies have had expansions or revisions since that time, so it must be realized that information is valid for the year 1972. This is true except for the three new properties of Sacaton, Metcalf, and Pinto Valley. These three operations started up since 1972 and all information for them was obtained in 1975. The questionnaires were sent to all major copper properties throughout the world as well as to many smaller units and to some mines that had complex or unusual conditions. Properties for which no information is given did not submit completed questionnaires. Several operations were unable to supply information requested be¬cause of company policy prohibiting it. However, data is presented for 75 different operating properties. The reference number of the left-hand column is the same for all 15 tables of data. If the company had several operating properties as of 1972, then subsequent properties use the same number but a different letter. For example, Anaconda's property at Butte, Mont., is IA, whereas Anaconda's (now Anamax) Twin Buttes property in Arizona is IB. Table I gives general data for the properties including exact loca¬tion, milling rate, pertinent assay values and recoveries, and a brief listing of ore and gangue minerals. It was not possible to obtain any more information from the properties in Chile except that given in Table I. Crushing. Crushing plant operating data is given in Table 2. This table gives data on the crushers, feeders, and screens used at each property. The data obtained on feeders was confusing, but, rather than completely eliminate this information, it was decided to report it as given. The confusion lies only in the description of where the feeder is located. Where a primary feeder is listed it was not possible to determine if this feeder was on primary feed or primary discharge. For secondary feeders it is known that the feeder listed usually is feeding the secondary crushers, but at some properties it is handling the secondary crusher discharge. The same reasoning holds true for tertiary feeders-they handle either tertiary feed or discharge. This table contains a voluminous amount of data. A column giving tons per day per square foot of screen area would have been very informative, but some properties included circulating load in the feed rate and others listed new feed only, so calculations were meaningless. Autogenous Mills. The use of autogenous or semiautogenous mills for any property must be given serious consideration in the future. Table 3 lists data for four properties that are fully autogenous and four more semiautogenous mills that use balls to supplement the chunks of ore. This method of grinding is especially applicable when the ore is of such a nature that crushing problems would be severe, such as when ore is wet or sticky or contains a lot of fines. Paradoxically, it should also be considered when ore is tough and hard and blocky because then the competency of the ore means it can serve well as the grinding media. Where the ore varies greatly in hardness, as at Cyprus Pima and Lornex, semiautogenous grinding has been especially beneficial with capital costs and operating costs both 10-20% lower than could be obtained with conventional crushing and grinding. Rod Mills. For a great many years the standard milling operation used two- or three-stage crushing followed by open circuit rod mills and then ball mills in closed circuit with classifiers of some kind. A surprising number of properties crush to the fine size of about 3/8 in. and then use ball mills only, in closed circuit, with no rod mills. It is difficult to say whether rod mill-ball mill circuits or ball mill only is the best. One can be certain of two things: (1) the argument will go on for a long time and (2) for some mills one method obviously was superior over the other. As ball mills of 14, 15 ft, and larger came into use, more properties like Duval Sierrita (16b ft diam by 19 ft long) and Bougainville (18 x 21 ft) were built with single-stage ball mill grinding. Although there are larger rod mills used, especially in the iron ore industry, the largest rod mills on copper ore are at Twin Buttes (14 x 18.5 ft) and at Gibraltar (13'A x 20 ft). Table 4 lists operating data for rod mills. If a company is listed in Table I

Jan 1, 1985

By P. R. Hervey

Quartz is the second most widely used electronic material, with approximately 3,000 tons of single crystals used each year. Virtually all of this material is synthetic; grown with a technique called hydrothermal growth. We will review the basics of hydrothermal growth, the feedstocks for these crystals, and the challenges to improving the growth process. We will also review the processing of these crystals, the markets and applications where they are used, and the global outlook for these markets.

Jan 1, 1999

By R. L. Grayson

Productivity achievements in underground coal mining over the past ten years highlight the improvement of management practices as well as the adoption of new technology. Research findings and results from operational studies characterize the aspects of good management that translate into high productivity. In concert with these findings, the Mine Management Support System (MMSS) is being developed, under co-sponsorship of the U.S. Bureau of Mines and the West Virginia University Energy and Water Research Center, as a knowledge-based system to enhance more efficient management of underground coal mines. Concentrating on capturing the intricate knowledge needed to manage a mine effectively, MMSS will encompass information and rules on work scheduling, desired work practices, regulations impinging on operations and planning, responses to operating problems, and the labor-management work agreement.

Jan 1, 1990

By J. T. Clancey

The potential inadequacy of natural gas reserves to supply projected requirements in the 1980's has been pointed out.(1,2) As a result, interest has arisen in the development of new, potentially low-cost processes for the conversion of coal into high BTU gas. In June, 1964, the office of Coal Research (U. S. Department of interior) and Consolidation Coal Company (now a subsidiary of Continental Oil Company) entered into a contract to continue work on coal gasification utilizing the Consol CO2 Acceptor Process. Work under this contract has been specifically directed toward the use of lignite as the carbonaceous feed, although the process is also applicable to non-caking subbituminous coals. The primary objective of this work was to establish the technical feasibility in continuous bench-scale equipment, of the novel features of the C02 Acceptor Process. Secondary objectives were the testing of commercially obtainable acceptors and the design and economic evaluation of a commercial facility. The bench-scale process development has been completed successfully and the construction of a large pilot plant at Rapid City, South Dakota, has been authorized. It is the purpose of this paper to review the technology of this new gasification process and to present the current projected economics of a plant producing 250 MM SCFD of pipeline quality gas.

Jan 1, 1969

By Peter G. Zambas

In planning an underground room and pillar mine, the selection of the shaft or portal location and the orientation of the main haulage arteries is of paramount importance, particularly in view of the high dependence of the cost of truck haulage on the proper definition of these parameters. In an effort to facilitate this selection a computer program was written which, by relating the truck characteristics to the areal configuration of the property or ore-body, derives the volume-weighted total fuel and time requirements for hauling ore from every panel within the property to a specified portal or shaft location through a predetermined gridwork of haulage drifts. By varying the size and orientation of the gridwork and the location of the portal or shaft access, an infinite number of configurations can be investigated. The results of this analysis can be plotted to indicate the optimum conditions.

Jan 1, 1971

By G. W. Johnston

INTRODUCTION For many years mining at the Stobie mine of the Inco Metals Co. consisted mainly of fill-type mining for higher grade ores and block caving or blasthole open stope mining for lower grade ores. Open stope mining, although quite favorable in the initial stoping phase, has always presented problems in the pillar recovery phase, especially at depth. In 1966, sublevel caving was introduced. This method is ideally suited for low-grade ore and can be applied very successfully to intermediate or higher grade ores providing proper controls are enforced. Sublevel caving has three distinct advantages: it is highly adaptable to mechanization; it recovers the ore in one operation; and it provides adequate ground sup¬port and safety regardless of mining depth. This method does, however, make extra demands, particularly for new types of supporting services. The constant presence of rock makes quality control of the grade of the ore being extracted essential. Increased de¬velopment, different types of ventilation, roadways, and maintenance are only a few of the many changes re¬quired. The care and maintenance of the fleets of diesel equipment and the modification of equipment is a con¬stant challenge. CHOICE OF SUBLEVEL CAVING The question arises, why mine by sublevel caving? Fig. 1 shows a typical problem encountered by the open stope or blasthole mining method. Near the surface there is little or no ground support problem. As mining progresses to an intermediate depth, however, ground failure starts to occur in the supporting pillars. If open mining is carried beyond this point, the critical depth is soon reached, accompanied by hanging wall caving, ex¬tensive pillar failure, and the danger of losing control of the mining cycle. The rock caved from the hanging wall mixes with and dilutes the ore being extracted from the blasthole stopes. Ore losses occur when pillar failure pre¬vents drilling and development of part of the ore. The interruption to the mining cycle causes serious curtail¬ment in production until ground failure is controlled and the mining method changed to adapt to the new conditions. Having recognized the limitations of open stope min¬ing, alternatives were sought. The first alternative (Fig. 2) was to fill the open stopes with sand fill be¬fore extensive pillar deterioration occurred, recover the pillar ore by fill mining, and then convert to total fill mining below. If the ore grade is high enough it can support the costly fill method. Recovery will be at a much slower rate and will therefore extend over a longer period of time. On the other hand, sublevel caving gives complete primary mining recovery in a short time and is very adaptable to mechanization, which is now a necessity to combat spiralling labor costs and give greater produc¬tivity per man. Sublevel caving is ideally suited as a mining method for low-grade ore bodies which eventually reach a criti¬cal depth for open stope mining. DEVELOPMENT The development phase comes first and of course its main purpose is to gain access to the ore and provide a route for ore removal from the mine. Initially a 20% inclined service ramp is driven in the footwall rock (Figs. 3, 4, and 5). It is preferable to start at the top of a mining block and drive the ramp down¬ grade so gravity can assist in mucking the blasted de¬velopment round, and also access can be gained more quickly to the initial production area. The ramp nor¬mally turns at 3.1 rad (180°) about every 152.4 m (500 ft) to keep it reasonably close to the rock disposal

Jan 1, 1982

By F. S. Knoll

GENERAL INTRODUCTION Electrostatic separation has found a number of applications since its initial installation as a processing method. Three broad types of electrostatic installations are discussed in order to provide a practical guide for three widely divergent uses of electrostatic separation. Only operating and installation data are covered in detail. A detailed technical treatment on the various types of electrostatic separation described in this paper can be found in the literature by F. S. Knoll, J. B. Taylor and J. E. Lawer.8, 9 ELECTROSTATIC SEPARATION OF IRON ORE: WABDSH MINES, CANADA Introduction Electrostatic roll-type separator technology which had been in use in various forms since the 1920's evolved in the late 1940's when this separation process was developed and applied to the extraction of titanium bearing minerals from beach sands by J. H. Carpenter. Equipment design and industrial flowsheets developed for the recovery of rutile and ilmenite found new application in iron ore by chance in the year, 1956. From the time of the first beach sands plant, Carpco had developed other technology, gravity and magnetic separation to better serve the beach sands industry. It was in the fall of 1956 that an iron ore producer from the upper Michigan Peninsula sent a sample of jaspilite (fine-grained specular hematite in a jasper matrix) to Carpco's laboratory for the purpose of determining if a new high-intensity magnetic separator would be beneficial. Process Development W. P. Dyrenforth, while presenting a paper on the subject in the fall of 1957, recounts the laboratory tests. "High-intensity magnetic separators have been employed (for the beneficiation of iron ore) with some success and are still being investigated. Magnetic separation is a natural field of investigation, since iron and magnetism have been almost synonymous since ancient times. As a matter of fact, when Carpco first began investigating the possibilities of upgrading specular hematite, the first thought was in terms of magnetic separation; and the second thought was in terms of gravimetric separation. It was found

Jan 1, 1986

By W. H. Jang

Recent research has demonstrated the utility of the FTIRIIRS adsorption density equation for in-situ study of surfactant adsorption phenomena at the surfaces of reactive internal reflection elements (IREs). The FTIR/IRS adsorption density equation is given by (formula) where r is the adsorption density, A/N is the absorbance per reflection, e is the integrated molar absorptivity, 4 is the bulk concentration of the surfactant, d. is the effective thickness, and dP is the depth of penetration. Previously, the validity of the adsorption density equation had been confirmed only from solution depletion measurements with high surface area powders. Now, FTIR/IRS studies of Langmuir-Blodgett (LB) monolayer films of fatty acid transferred to the surface of a calcium fluorite IRE .clearly validate the reliability of the FTIR/IRS adsorption density equation for quantitative analysis of surfactant adsorption. In addition, it was confirmed from the observed absorption band at 1550 cm-1 that the first monolayer of the transferred fatty acid chemisorbs at the surface of fluorite.

Jan 1, 1994

By Thomas L. Craig

The Wellman-Lord SO2 Recovery Process is operating commercially at one location in this country and at two locations in Japan. Tail gases from a sulfuric acid plant, from an oil fired steam generator and from a sulfur recovery unit are the respective applications. 1) At the Olin Corporation's Paulsboro, New Jersey, stack gas from a spent acid regenerative sulfuric acid plant-45000 SCFM - is treated in the W-L unit to reduce sulfur dioxide concentrations from 4500 ppm to less than 500 ppm. 2) At the Japan Synthetic Rubber plant in Chiba Prefecture, stack gas from an oil-fired steam generating plant - 120,000 SUM - is reduced from 2100 ppm S02 to less than 200 ppm. 3) At the Toa Nenryo Kogyo refinery in Kanagawa Prefecture, tail gas from a sulfur recovery (Claus) unit - 41,000 SUM - with, an inlet SO2 concentration of up to 13000 ppm is reduced to less than 200 ppm. The three installations are operating successfully and are capable of reducing S02 emissions to levels significantly below the concentration guaranteed. With the one exception of a higher than guaranteed chemical make up requirement at Paulsboro, utility and chemical requirements will be less than design.

Jan 1, 1971

By Dipl. -Ing. Mertens

Gentlemen: I am pleased and regard it as a priviledge to give you a report on rapid roadheading with heading machines in the coal mining industry of Western Germany. Importance of Heading Operations in the West German Coal Mining Industry Every year about 770 km of headings are driven In the seams of the West German coal mines, most of them gate roads, the rest rise headings, to open new faces. In thick seams the heading operations are carried out entirely in the coal, in thin seams the country rock has to be ripped. The total length of 770 km corresponds to a rock volume of roughly 9.5 million m3; this figure underlines the importance of the heading operations in the coal mining industry of our country.

Jan 1, 1970

By H. B. Charmbury

In Pennsylvania there are two distinct coal regions, bituminous and anthracite, in which the mining conditions and production trends are different. Bituminous mining is more mechanized, and production is increasing. This report is concerned specifically with the bituminous area. The bituminous coal industry apparently is facing a shortage of miners and mine officials which may become acute by 1970. Since 1949, when Pennsylvania had more than 100,000 bituminous coal miners, the number has steadily decreased. There are two principal reasons for the decrease of certified miners and mine officials. These reasons are the fact that apprentices are almost a thing of the past and the fact that the image of the coal miner is a poor one to people in general and to parents in particular. This has contributed greatly to the high average age of our miners today. The average age of all those employed in the mines is 50. Yet it is known that the progress in mine mechanization requires younger and more alert men to operate the newer type equipment.

Jan 1, 1966

By John E. Good

A new coal boom is under way in western Canada. As recently as the mid-1960's, the coal industry in western Canada was considered stagnant and, by some people, dying. But Japan's growing need for coking coal, which became more pronounced in 1966, sparked great interest in western Canadian reserves.' As a result of a rapidly expanding export market and growth in domestic demand, Canadian coal production spurted to 16.6 million tons in 1970. Production in 1965 was 11.5 million tons. Today, about 60 percent of Canada's output comes from western Canada, but by 1975, 87 percent (23.1 million tons) is expected to come from this area, and 96 percent (68.3 million tons) by 1990. Opening, developing and operating new coal mines to meet the needs of a rapidly expanding market for western Canadian metallurgical coals pose some unique and difficult problems. Covering nearly every aspect of opening properties in remote areas, the problems are met in exploration, transportation, construction, mine operations, coal preparation, manpower and ecology. Paul Weir Company has been involved as coal consultants on various projects in western Canada for some years. In presenting this paper, we make no attempt to present an in-depth or detailed analysis of any one specific situation. Each has, or would have, its own peculiarities or characteristics, both physical and economic. Instead, the objective is to provide for those not intimately

Jan 1, 1972

By Z. Man, X. Zhu, Y. Xian, Y. Tao

"Fine coal separation has been always concerned. The froth flotation is not efficient in desulfurization because of the low rate of sulfide liberation from raw coal, the natural hydrophobicity caused by sulfur concentration on the surface of sulfide, and the presence of large amounts of middling feed. An efficient centrifugal gravity separator was employed to separate for Shandong –0.5mm high sulphur coal, the partition curve of centrifugal separator was obtained with conclusion that the Ecart probable error value of the separator is 0.095, the imperfection I value is 0.128. Finally, comparing with the coal flotation using progressive release method, the result shows that the effect of the desulfurization with centrifugal gravity force field based on density difference between coal and minerals are much better than that of the floatation which operates based on the difference in surface properties. It provides a efficient technical way for fine coal separation. INTRODUCTION Coal plays the most important role in the energy consumption in China. Although natural gas, wind energy, nuclear power has made great progress in recent years, but the share of coal in the final energy consumption accounts for 70-80%, which is determined by energy storage of China. Under the requirement of environmental protection, the clean utilization of coal resources becomes more and more important, and the need has already been identified. Coal washing and processing plays an important role in the process of high-efficiency and clean utilization of coal. For the separation of fine coal, flotation is a traditional method for effective separation and has been used in large scale industrial applications in coal preparation plant. However, for the separation of difficult-to float coal, especially fine oxidized coal and low–rank coal with hydrophilic surface, flotation is usually inefficient [1-3]. Although many pretreatment methods have been adopted, including grinding, microwave pretreatment, new flotation reagents, the problem of efficient separation has not been completely resolved [4-6]. Thus, an enhanced gravity separation method using particle density difference rather than hydrophobic difference was proposed for the separation of fine coal. Many research results have proved that this is a practical and effective method of sorting. R.Q. Honaker used Falcon C10 concentrator, Knelson centrifugal separator and spiral separator to clean the fine coal with size of 600*210 µm and 210*37µm, the effects of different operating parameters on the separation index was discussed. The results show that the separation density of Falcon can reach 1.6, and the Ep value can reach 0.1-0.15. This paper revealed that for the separation of fine coal with high sulfur content or fine grained content. Falcon has high separation efficiency with low cost. Separation results present in another paper showed that the desulfurization efficiency of inorganic sulfur was better than that of flotation [7-8]."

Jan 1, 2017

By Harry Leslie Bullock

With silica making up more than 27% of the earth's crust, its oxides amounting to more than 59% of the igneous rocks and quartz the most prevalent of the main free oxides, it follows that the mining engineer' is in constant contact with quartz, mainly as a gangue material to be removed as completely and economically as possible and sometimes as a valuable mineral to be purified' for the chemical,, ceramic or glass industries. Water scarcity under desert or semi-arid conditions, dwindling water supplies and difficulties of wet waste disposal in many locations and trouble from freezing in arctic locations make dry benefication more and more desirable. Advances made during the last few years in apparatus and methods and a steadily increasing knowledge of solid state physics are widening the field open to the economical application of electrostatic separation.

Jan 1, 1967

By J. L. Carr, A. K. Smith, C. C. Jobes, G. T. Homce

"Underground continuous mining machines pose a difficult safety challenge since their operators generally work in close proximity to these machines in very restricted spaces. Intelligent software for use with magnetic proximity detection systems has been shown to accurately locate workers around mining machinery in real time. Calibrating these systems requires the manipulation of a lot of data to determine the calibration constants. Researchers have developed software to analyze, convert, and visualize data acquired during this calibration process to more accurately model magnetic fields and their interaction with the environment. This paper details the background, development, and operation of the resulting application software focusing on the utility of the graphical user interface to visualize the magnetic field calibration data. The refined data developed by this process can then be utilized by the proximity detection system to more accurately identify the location of miners working in an underground mining environment. INTRODUCTION Roughly half of the electricity consumed in the United States is produced with coal, and roughly one-third of all US coal production comes from underground mines [1]. Over the last century underground mining health and safety has seen a continuous and dramatic improvement. However, machine-related injuries and fatalities continue to be a major safety concern [2]. Every year, hundreds of miners are severely injured while operating underground mining equipment, and 39 miners have been killed in striking/pinning accidents involving continuous mining machines (CMMs) since 1984. CMMs, such as the one shown in Figure 1, are large mobile machines that are used to mechanically cut coal in an underground mine. These machines weigh approximately 40 to 50 tons, have hydraulically articulated appendages, and are capable of moving at speeds up to six feet per second [3]. Modern CMMs are remote-controlled, yet the operator and other miners are often in close proximity to the machine. Recent research by the National Institute for Occupational Safety and Health (NIOSH) reveals that the locations workers take relative to the CMM are usually influenced by visibility requirements and safety concerns [4]. The Mine Safety and Health Administration (MSHA) estimates that at least 28 fatalities involving CMMs since October of 1984 may have been prevented with proximity detection technology [5]. MSHA further estimates that proximity detection could prevent 20% of all deaths throughout the industry [6]."

Jan 1, 2016