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By W. G. Miller

A series of computer programs for the analysis and mapping of coal-related data has been developed at the Illinois State Geological Survey; these programs, known collectively as the Coal Data System, represent the latest achievements in computer processing of geologic data at the Survey. Building upon programs previously developed in the Survey's Computer Services Unit, they expand the scope of the computerized data base that the Survey has been using for analyzing coal-related data. The System was partially developed during a joint study by the Illinois State Water Survey and the Geological Survey entitled, ?Coal and Water Resources for Coal Conversion in Illinois.? 2 In that study the available coal reserves more than 42 inches thick in the two principal coal seams throughout the state were mapped. The System was used to calculate the coal reserves and to report the average number of tons of coal in place per square mile in each township (Figures 1 and 2). It also produced maps of the coal features of sufficient quality to be printed on material that was scribed as master copy for the printing of full-color 1:500,000 scale maps (see Figures 3 and 4).

Jan 1, 1975

By D. Bahrami, G. Danko

Spatial and temporal temperature and humidity variations for 5000 years are simulated in an emplacement airway within the conceptual, high-level nuclear waste repository proposed to be built at Yucca Mountain, Nevada. A multi-scale model is configured using MULTIFLUX, a thermohydrologic-ventilation code. The predicted surface temperature of most waste packages during post-closure exceed 140oC, the threshold limit known for likely localized corrosion for Alloy 22 waste package material. Small amounts of infiltration airflow through the mountain in Panel 5 are found to transport liquid water condensate to some of the waste packages emplaced along the peripheral section of the drift due to edge cooling.

Jan 1, 2004

By S. M. Hsiung

This paper presents the results of an extensive study concerning a series of roof falls in a room-and-pillar coal mine located in West Virginia. Three dimensional finite element modeling was employed to identify the possible causes for the roof falls. The effectiveness of possible roof control measures for alleviating or eliminating the adverse roof conditions is analyzed, discussed, and compared. The best mining alternatives are recommended. It has been found that large overburden depth and typical roof geology are the major reasons for the roof falls. Angle bolting may not solve the problem encountered in the mine studied. Changing the mine layout currently used in the mine appears to be the best alternative. The recommended pillar size and entry width which will eliminate the problem completely are 90 ft. x 90 ft. and 14 it., respectively.

Jan 1, 1985

By R. J. Sweigard

The effects of postmining land use planning are addressed in this paper. These effects may include savings in reclamation costs and increased value of reclaimed land. However, this may result in greater planning costs and possible delays in production. Therefore, an economic analysis was undertaken in an effort to determine the importance of each potential result and to quantify the overall economic impact of postmining land use planning. A discounted cash flow analysis was performed using a surface mine cost model to analyze the sensitivity of selling price to changes in various postmining land use planning parameters. As a result of this analysis it was determined that the profitability of a project is most sensitive to delays in production, particularly, if the delay occurs after major investments have been made. Many methods have been proposed for evaluating postmining land use alternatives (Sweigard and Ramani, 1981). Both quantitative methods, such as benefit-cost analysis (Brock and Brooks, 1968), and nonquantitative methods have been proposed. The application of one specific analytical method is pursued in this paper.

Jan 1, 1985

By Anthony G. Fonseca

The acid leach-solvent extraction processing of oxide copper ores can be improved when selected cation additives are utilized. Bench scale testing showed improvements in both sulfuric acid leaching and solvent extraction processing. Treatment with the method to be described shows improvement in copper recovery in the acid leaching section as well as reduced acid consumption and reduced iron and aluminum dissolution. Processing the copper bearing leach solution with LIX-64N shows increased loading of the LIX reagent which relates to reduced aqueous and organic flow rates, reduced organic loss and inventory as well as a reduction in the size of mixer-settlers. The use of selected monovalent cations controls fluctuations within the pro- cessing system to accomplish the above named improvements. Additionally, these cations are totally compatible throughout the processing system and are quite inexpensive. Bench scale recycle data will be presented both for the leaching section and the continuous solvent extraction processing section up to (but not including) processing the loaded electrolyte. Material balances as well as major solution component monitoring will also be presented.

Jan 1, 1975

Conventional logging tools such as density, neutron, and acoustic have ranges of investigation of tens of centimeters. The borehole gravimeter, however, has a range up to hundreds of meters. For example, from the center of a cylindrical orebody 0.22 g/cm3 denser than its surroundings, one can detect the boundary of the orebody at a radius as large as five times its height. More complex structures can be investigated with computer programs. We can predict the usefulness of proposed gravity surveys, or decide which suggested structure is most likely to have caused the results of existing surveys.

Jan 1, 1985

By C. B. Daellenbach

The influence of reduction roasting and thermal shock on the grindability of a refractory low-grade Michigan iron ore was examined in bench scale tests. The quantitative effects of the various treatments were evaluated at three sieve levels: 48, 100, and 400 mesh, using ball mill grindability and work index parameters as response indicators. Data from the testing program were analyzed statistically as a means of isolating the effects of cooling rate, roasting temperature, and ore chemical condition. All three variables were found to have an important influence on the grindability of the treated ore; ore chemical condition and roasting temperature had the most pronounced effects.

Jan 1, 1970

By Joseph W. Siefke

The Kramer borate deposit is located in the western Mojave Desert at Boron, California, about 100 miles northeast of Los Angeles (Figure 1). The deposit derives its name from the district in which it lies. Borax (Na2 B407.10H2O) is being mined from the Boron open pit to serve a major portion of the United States and world borate markets. This paper deals primarily with those geologic factors which affect slope stability in the overburden at the Boron open pit. Discussion includes slope failure history, slope monitoring techniques and the results of a dipmeter survey of overburden structure. Open pit mining was begun at Boron in 1957. The initial pit was successfully excavated at the recommended 1.5:1 (horizontal to vertical) slope in the overburden. During pit expansion in 1962, excavation of the overburden exposed beds dipping into the pit at +15 degrees and numerous high angle fractures associated with two intersecting fracture systems, the West Jenifer and Portal fault zones. Ensuing south and east wall failures indicated the need for more structural information in the arkose to establish better wall design criteria. Barnard and Kistler (1963) recognized that the many facies changes, faults and other variables in the Boron overburden make it extremely difficult to reduce prediction of slides to a simple arithmetical formula. Despite the difficulties and uncertain¬ties, special programs such as surface resistivity, refraction seismic and core drilling were conducted in an attempt to predict slope stability conditions and to gather geologic information. These early efforts while helpful, did not provide the necessary details of bedding orientations and fault locations which are of paramount importance in our slope stability program. A dipmeter survey in 1974 successfully measured these variables and data from that survey are instrumental in the design of slopes currently being excavated.

Jan 1, 1976

By G. V. Borquez

For many years drilling and blasting has been considered more of an art than a science. This is still true in some respects, but today scientific approaches to drilling and blasting design must be used to plan an efficient operation which achieves desired fragmentation within constraints. These constraints involve minimizing damage to the wall or nearby permanent structures and avoiding undesirable fragmentation and mine dilution which can adversely affect operation costs. The degree of fragmentation by blasting is the most important single factor in any attempt to optimize the overall cost of the mining operations. The mining cycle begins with the drilling and blasting operations, which result in a given blasted rock size distribution. While this operation represents only about 20% of total mining costs, the efficiency and costs of the subsequent operations are strongly dependent on the fragment distribution obtained.

Jan 1, 1986

By Alvin W. Schillinger

Drilling was not entirely satisfactory in the search for native copper in the Osceola amygdaloid footwall as mining showed oreshoots to be more continuous than drilling indicated. The Geophysics Department of Michigan Technological University developed a portable induced polarization drill hole probe with a 3 electrode configuration and a sampling radius of 5'± A 20 ma current of alternately reversed polarity is pulsed at 3.5 sec. intervals and readings are taken every two feet. Potential is read during the "on" cycle for resistivity determinations. During the "off" cycle, after 10 ms delay, the I.P. potential is sampled for 10 ms and recorded. Resistivity (ohm-feet) and "S" values (mv/v) are plotted on semi-log paper. A lithologic log is plotted based on resistivity and anomalous "S" values noted. The low resistivity amygdaloid contains sills of high resistivity basaltic trap. Verified by core logs, amygdaloid-trap contacts could be picked to ±.5' from resistivity alone. Lithologic logs of long steel holes, based' on resistivity, now replaced sludge logging. An "S" value of 30 mv/v was established as the lower limit of diagnostic I.P. effects in mineralized amygdaloid and 50 mv/v as a threshold value for ore. Of 914 footwall zones drilled, 315 were probed yielding 203 anomalies. Success increased from 34% for drilling to 72% for drilling and probing. As checked by mining, 46 probe results were 78% correct. Failures were due to the instrument not detecting copper or to the misinterpretation of an anomaly. No false anomalies were found.

Jan 1, 1964

By Eugene C. Robertson

The exchange of heat from wall rock to ventilating air was studied in a cross-cut driven through fresh rock on the 4600 level of the Kelley Mine, Six- teen thermocouple probes, 10 inches long, twenty-three probes, 7 feet long, and five probes, 50 feet long, were emplaced in the walls soon after blasting and wall -rock temperatures were monitored intermittently over a two-year period to determine heat loss from the wall rock. Temperatures, humidity, and velocity measurements were made of the air at the same times to determine heat gain. An important but less well-defined variable was the heat transfer by water entering the crosscut from fractures and leaving in the ditch. The balance of heat in and heat out at each probe station is within an acceptable range. Theoretical and empirical models for heat flux into a cylindrical opening fit the data reasonably well, also.

Jan 1, 1970

By Young C. Kim

In the past, underground coal mine planning has traditionally focused on the mine design n aspects concerning safety and efficiency in the quest to produce low cost coal. Very little attention has been given to coal quality control aspects of mine planning at most of the underground coal mines within the U.S. With the enactment of the clean air act of 1970, the generally high sulfur content of coal has become a major concern for the coal-fired power plants in the east. Similarly, the ash and the BTU contents of coal are of equal importance from boiler efficiency standpoint. Thus, the time has come when the coal mine planning must incorporate the coal quality control aspects as well as the traditional safety and efficiency aspects.

Jan 1, 1983

By James A. Clum

The shift to lower grade iron ores, e.g., magnetic taconites, resulted in a shift towards agglomeration practices which could effectively deal with the fine particle sizes generated in the liberation and concentration processes. If the iron bearing particles are not extremely fine, e.g., -1/2 in + 100 mesh, sintering is an adequate means of agglomeration.(1) For the more dispersed ores which result in fine concentrates (more than 80%,-325 mesh), the fine particles must be agglomerated by mechanical means before final hardening, e.g., pelletizing.(1) In the pelletizing process, the essentially mechanical step of balling is extremely critical since the strength of the pre-fired pellet determines the firing conditions. The ability of the proper amount of moisture to hold together a ball of the very fine ore concentrate particles has long been recognized. It is a charac¬teristic of the reaction at the interface between the ionic solid of the ore concentrate and the polar water phase which overlays the solids. The strength in such moisture laden balls, the green strength, is a strong function of the water content (Figure 1) and thus deteriorates rapidly for either a small excess or a small deficiency of moisture. For purposes of commercial practice, the control of green ball handling properties by accurate control of ball moisture is too demanding. Moreover, as the ball is heated towards its hardening tempera¬ture, e.g., 1300'C, there is a substantial drying reaction which would lead to such a low dry strength of the ball that it would not support its own weight much less the weight of other balls in a firing furnace.

Jan 1, 1976

By C. R. Peterson

A cutter vibration monitoring system is described which would map seam strata non-uniformities to permit guidance within the seam. An extremely simple and rugged transducer is used which is compatible with conventional cutters and cutter replacement practices, and believed to be suited to the mining environment. Laboratory tests show that the system can detect bedding planes in otherwise homogeneous material. A data display system which would employ the human operator's natural pattern recognition skill and judgement will be developed, Intended for remote control applications in general, the system is of direct interest for today's continuous excavators in coal or in any other machine excavated bedded deposit.

Jan 1, 1985

By J. LeRoy Peterson

This paper presents some of the theoretical aspects as well as some results of actual plant operation of the Ty-Hukki Classifier. Dual classification steps within a unit vessel are achieved by controlled separation of the sand product under turbulant flow conditions, followed by further classification under strictly laminar flow conditions. Plant operation has shown some of the benefits of the superior sharpness of classification to be reduction of circulating load in grinding circuits, prevention of overgrinding, increase in mill feed rate and consequent reduction in cost per ton of ore.

Jan 1, 1966

By Russ Darr

New methods and techniques in the field of hydrogeology are being developed constantly. One of these advances has been brought about through the use of inexpensive microcomputers. The formulas used in this paper and developed by Theis, Jacob, Glover, Keck, and Dupuit are not new. The methods by which these formulas can be solved are now available to all who wish to get faster, less expensive, and more reliable answers. These methods involve the solution of standard groundwater formulas using microcomputers. Examples and case histories of these methods are presented

Jan 1, 1980

By Ernest B. Snyder

The word "line" has been used loosely for many forms of the common steel plant flux. For example, many people use the word "lime" for nigh calcium and dolomitic limestone, for high calcium and dolomitic quicklime (also called caustic lime, calcined lime; burnt lime, pulverized and pebble lime) and ;van for clinkered dolomite. Calcium hydroxide, also called slaked lime and hydrated lime, is called "lime" but is seldom used as a flux except when the quicklime air slakes in open boxes or bins. All of the above forms of "lime" are used in the steel plant. Calcium hydroxide is used for water treatment, acid neutralizing, and as a lubricant for wire drawing. All the other limes are used as fluxes in the sintering plant, blast furnace or steel producing furnaces. In the production of self-flux or super-flux sinter, high calcium and dolomitic limestone fines are used. Where quicklime fines are available, they may be added to the sinter mix also. The blast furnace uses both high calcium and/or dolomitic limestone. A few trials have been made using iron oxide stabilized dolomitic lime in an attempt to reduce coke consumption and to increase the production rate. The trials were very successful but would' not be economical, except in periods of coke shortages, with resulting extremely high coke cost and exceptionally high hot metal demand.

Jan 1, 1979

By Daniel H. White

Block caving, unlike most other conventional forms of mining relies principally on the natural forces within the rock mass to fragment and transport the ore. Obviously, not every orebody can be satisfactorily mined by block caving. In the early stages of mine planning an attempt should be made to assess the benefits of the block caving system relative to others, and develop a reasonable mining concept that may be used to provide preliminary information to mine planners and financial specialists. It is the intention of this paper to outline some basic geotechnical parameters that are essential to: 1) Assessing the feasibility of block caving an orebody and 2) Providing semidetailed information relative to mine design based on drill hole and other data.

Jan 1, 1979

By Michael R. Birkos

A new electrotelluric prospecting technique allows the mapping of ore body distribution, lithologic contacts, and voids with accurracy comparable to core drilling. Data is available almost immediately and presented in a format similar to a downhole log. This is done with a passive surface receiver that transduces electrotelluric radiation into an audible signal. Changes in the character of the audible signal lends insight into lithology, porosity, fluid type and medium. Three case histories are presented. The first delineated a paleochannel within a coal seam. The second traced old mine workings and backfill areas. The third identified a high-pressure karst void.

Jan 1, 1986

The deformation, failure, and filling characteristics of a caving roof in the initial and normal mining stages of a pitching oblique longwall mining area are analyzed using large-scale threedimensional physical-similitude experiments and numerical calculations to study the characteristics of roof fracture and migration in a steeply dipping seam. The results show that the roof fracture development has evident sequential and spatial characteristics. Among them, immediate roof breaking in different parts of the mining area shows difference in time and space. The failure sequence of the immediate roof in different areas changes with the mining; unique regional stability evolution characteristics are observed in the suspended immediate roof simultaneously, resulting in its significant regional stability on the goaf filling.

Jan 7, 2020