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By A. K. Ghose

The increasing application of roadheading machines in the coal industry has prompted the development of an appropriate selection methodology for such machine applications in specific locales. Accurate geological sections and comprehensive rock testing are required for all machine tunneling. Using suitable geotechnical parameters and index tests, sensitive both to excavability and standability of the strata, a classification scheme has evolved to help evaluate the rock mass vis-a-vis application of a given weight-class of roadheading machine. The classification parameters include point load index, brittleness, abrasiveness, average crack density, and ground water, which with assigned numerical ratings, lead to a quantitative global rating of the rock mass. For each rock mass class, the selection of an appropriate roadheading machine is recommended. The paper illustrates the application of the rock mass rating system and also describes simple index tests for evaluating the classification parameters for brittleness and abrasiveness. Manuscript not received in time for publication.

Jan 1, 1983

By Robert E. Jones

The barite industry shares with its associates in the minerals industry the impediments of excessive federal and state regulations. We have learned to exist with the Organic Act of 1976, the Mine Safety and Health Act of 1966, and the Multiple Use Act of 1955. I do not mean to imply by the above that all aspects of mining legislation have been detrimental, however, each of you has been subjected to interpretative restrictions by federal or state bureaucrats. As frustrating and costly as this is to the barite industry, it is not the primary problem facing our segment of the industry at the present time. Our major difficulty today deals not with too much government regulation, but with the lack of a cohesive and consistent government energy program. This administration and those that have preceded it have dealt with intermittent energy crises on an emergency basis. If we remove the political rhetoric which has surrounded each of the more recent major crises, we can liken the action of our federal government to that of a rural volunteer fire department which devotes its entire efforts toward extinguishing existing fires rather than the developing of programs designed to prevent future fires. The lack of a comprehensive energy program has created an environment in which long range planning is extremely difficult, if not impossible.

Jan 1, 1983

By Wayne Hilgedick

Peabody Coal Company is the nation's largest producer of coal and is headquartered in St. Louis, Missouri. In 1978 Peabody divisionalized its operations to establish more responsive and effective mine management. Peabody Coal Company's Arizona Division operates two large surface mines, the Black Mesa and Kayenta Mines. Both are located in northeastern Arizona, approximately 30 miles from Kayenta, Arizona, on the Navajo and Hopi Indian Reservations. The Black Mesa Mine produces 4 to 5 million tons of coal per year and the Kayenta Mine produces 7 to 8 million tons per year. Coal from the Black Mesa Mine is transported 274 miles by coal slurry pipeline to the Mohave Generating Plant located on the Nevada/Arizona border at Bullhead City, Arizona. This plant is jointly owned by Southern California Edison, the Los Angeles Department of Water and Power, Nevada Power Company and Salt River Project Agriculture Improvement and Power District.

Jan 1, 1983

By D. G., Bosse&apos

Equipment choices for ultrafine grinding encompass several different types of dry and wet size-reduction devices. These need to be put into functional perspective for systematic analysis of capabilities and limitations versus processing requirements of the materials to be satisfactorily ground. Particle strengths plus maximum and average sizes are the primary variables controlling grinding action requirements and equipment options for efficient processing. These are fairly well understood and provide the starting point for decisions. Particle space requirements under dynamic processing conditions vary with particle shapes and size-distributions by as much as 30X. This additional major variable is not widely appreciated and does need adequate description to provide a firm basis for selecting processing compositions and procedures.

Jan 1, 1983

By D. J. Barratt

What is meant by "Minimizing Risk"? This paper explores some of the factors encountered in plant design which can affect the success of a mineral processing plant in terms of its planned output, quality of product and recovery. Any deficiency in either one of these objectives means lost revenue at the start of a project and reduced present value for the mine life. Time is money. Related factors such as project conception, feasibility studies, capital cost and operating cost estimation and mining studies have been covered in a recent paper (1) from which material for this paper has been drawn. What follows is a discussion of the principal factors which can influence the success of a project with particular emphasis placed on processing concepts.

Jan 1, 1983

By D. G. Bosse

Equipment choices for ultrafine grinding encompass several different types of dry and wet size-reduction devices These need to be put into functional perspective for systematic analysis of capabilities and limitations versus processing requirements of the materials to be satisfactorily ground Particle strengths plus maximum and average sizes are the primary variables controlling grinding action requirements and equipment options for efficient processing These are fairly well understood and provide the starting point for decisions Particle space requirements under dynamic processing conditions vary with particle shapes and size-distributions by as much as 30X This additional major variable IS not widely appreciated and does need adequate description to provide a firm basis for selecting processing compositions and procedures

Jan 1, 1983

By Robert Moore Lewis

A unit for separating minerals Into two prescribed size fractions, designated as a Lewis Hydrosizer, was developed at the North Carolina State University Minerals Research Laboratory Ore samples with different mineral compositions, including coal, were separated effectively with the laboratory continuous unit Commercial size units are in operation in North Carolina and Mexico, and under construction In Norway Additional units are being built or are in the planning stage at several companies.

Jan 1, 1983

By Thomas C. Wilder, Firoze E. Katrak

As part of a survey on the long range supply of gallium, a comprehensive review of the chemistry of commercial gallium extraction was undertaken Owing to its very small concentration in all commercial minerals, gallium can be produced economically only as a by-product of major extraction processes for other materials. A summary is presented for the chemistry of gallium extraction from many of these process streams included are several procedures for gallium recovery from bauxite, currently the most prevalent source Other processes described are from waste streams from the production of zinc, phosphorus from phosphates, aluminum from kaolin clays, and from coal ash, the largest potential resource A brief review of development of solvent extraction as a unit process for gallium recovery is also presented

Jan 1, 1983

By P. Somasundaran

The use of chemical additives in ultrafine grinding will be reviewed in this paper for the case of grinding of quartz in solutions of surfactants and inorganic electrolytes including some dispersants under different conditions of pH and ionic strength. Mechanisms are examined by correlating the grinding effects with those obtained for the influence of these chemicals on zeta potential, pulp fluidity and flocculation/dispersion characteristics. The analysis suggests grinding depends mainly on the state of aggregation of the ground products in- side the mill and the pulp fluidity. Implications of the observed effects on ultrafine grinding in general are discussed.

Jan 1, 1983

By Charles C. Mosher

An in-mine seismic technique for detecting faults has been tested in a Western U.S. coal mine. This technique has been used extensively in the U. K. to help guide longwall mining operations. Explosives detonated on the face of a seam generate sound waves which propagate into the seam. Reflections from faults are picked up by sensors on the same face. Computer processing is then used to determine the fault locations. A known fault was successfully located in this test. Modifications to the U. K. procedures were required for the relatively thicker roan and pillar mines common in the Western U. S.

Jan 1, 1983

By Lee W. Abramson, Kenneth P. Akins

The authors have accumulated published data on residual soil and rock tunnels in the United States and have compared it to transit tunneling experience in Atlanta, Georgia, and tunnels in other soil and rock conditions. Two 6.1 meter (20 foot) diameter shield driven, compressed air tunnels were constructed for the Metropolitan Atlanta Rapid Transit Authority (MARTA) connecting the Five Points Station (central hub) with the Peachtree Center Station (first station on the north line). Because of the historic multi-story structures above the tunnels and the variety of subsurface conditions, a comprehensive ground monitoring and observation program was conducted. Conclusions are drawn regarding residual soil and rock ground response due to tunneling. Comparisons are made to ground response due to tunneling in other soil and rock conditions.

Jan 1, 1983

By C. S. Simons

The aphorism that provided the title of this paper is probably a couple of hundred years old, but it still expresses a fundamental truth in the metals industry. This truth will be illustrated through a brief review of the major developments in the extractive metallurgy of the oxidized ores of nickel - the "laterite" ores. While the details to be discussed are for the most part specific to nickel, a close parallel with other commodities - particularly in recent years - will be apparent even to those whose interest in nickel itself is slight. Thus it is hoped that this paper will be stimulating, at the least, to anyone who is concerned with the implementation of process improvement, "Invention" in the present context means any change from "conventional" process technology that shows a reasonable chance of reducing costs, increasing revenues, or both, in the production of a commodity. This can be anything from a simple rearrangement of flowsheet steps to a completely different basis for processing. And the result may reduce costs by more efficient use of energy or labor or reagents; may increase revenues by better recovery of the primary product or by introducing the recovery of previously ignored by-products; may insure sales volume (and thereby cash flow) through higher product purity or an improved product form. "Necessity" is the perceived need to attain at least one of these classes of results. This perception of necessity, however, varies widely from management to management and from project to project.

Jan 1, 1983

By Floyd C. Bossard

In underground mining operations, the over- riding issue has to be protection of worker health and safety. The employees underground, making a living in a dangerous occupation, know these are major issues. These men bargain their lives and health on the presumption that the operating management knows its business, and they, the underground employees, can pursue their occupation with the assurance that management has provided a safe and healthy ambient underground environment. When management assumes the mantle of protection of underground workers, it has to be positive that qualified engineers have designed the project, and that capable operating personnel are in charge and always available. Those persons with these responsibilities must be knowledgeable in the engineering and occupational health aspects of sine ventilation. The ultimate function of a mine ventilation system is to provide a comfortable, healthy and safe ambient environment for the underground workers. The attainment of these objectives has been complicated with the increased application of electrical equipment and diesel-powered mechanized mining equipment underground (discharging toxic diesel emissions); increased production rates with the attendant increased production of airborne dust; and mine development in increasingly hostile mineral formations containing combustible strata gases, radon gas emissions, along with high heat and humidity. In general, the modern mechanization of present mining operations has resulted in a sore complex set of problems for the engineer planning the underground ambient environment.

Jan 1, 1983

By J. S. Hall

The performance of a full-scale balling drum circuit is well known to fluctuate, and is difficult to control. The fluctuations stem from causes that are not readily quantifiable. Results from plant tests show that surging of the recycle tonnage is dependent, inter alia, on the method of bentonite addition, small variations in drum or cutter bar speed and the method of drum water addition. This paper presents detailed observations from experiments on full-scale drum circuits, including preliminary results of a computer measurement and control scheme. Size distributions measured at points along an industrial drum are presented, together with the results of a mathematical model fitted to one plant data set. Model predictions are also included emphasizing the importance of screen performance on circuit stability.

Jan 1, 1983

By R. L. Miller

The potential for recovery of enriched uranium from spent nuclear fuel which has been consolidated into a nuclear waste form was explored in the studies reported here. The waste form of interest is iron-enriched basalt (IEB)--a silicate-based, fused-cast ceramic. IEB samples were prepared containing fuel assembly materials that simulate the core debris of Three Mile Island Unit II;1,2 the nominal composition of the consolidated waste form is given in Table 1. Ore Types The IEB samples, or man-made uranium ores (MMUO), are in two different mineralogical forms. Each MU0 was made by melting the constituent materials and holding at about 1500°C for 1 h. The MMUOs were then heat treated to control crystallization and crystal growth and then cooled to room temperature.

Jan 1, 1983

By Robert W. Roscoe

For over a century, St. Joe Minerals Corporation in Southeast Missouri has been sinking shafts for their lead mining operations. Upon discovery of the Viburnum Trend, or "New Lead Belt", St. Joe brought its experience and expertise in shaft sinking to the area. Eleven shafts were then sunk in an 18 year period, ending in 1972. In 1981, St. Joe began sinking a new shaft in the Trend with hand-picked employees from the four operating lead mines and service facilities. The paper describes the general history of St. Joe shaft sinking methods and equipment, focusing on the current development of the Viburnum No. 35 Shaft.

Jan 1, 1983

By Ralph W. Barbaro

In the mineral industry, the objective of a mining venture is to extract, process, and market a mineral commodity in such a manner that the profit of the venture is maximized. In a mining venture, a company normally has control over mine production scheduling, the selection and location of processing facilities (mineral beneficiation plants, smelting plants, refineries, or blending facilities), processed ore blending, and the selection of markets. The flexibility of the above factors provides many alternatives to satisfy the needs of each market with regard to quantity and quality of ore. The purpose of this paper is to present a mathematical model for determining the alternative that yields the maximum profit. Production planning is generally concerned with the best utilization of fixed resources, more specifically, with the determination of production and inventory levels to meet fluctuating demand requirements. A mine can be any source of ore such as an entire mine, a production unit within a mine, or an independent supplier. The objective of production scheduling is to determine the times at which each mine will be used and to allocate a required level of production. Production planning and scheduling problems are intimately associated with the location of new and existing mines and processing facilities. Although the location of the mines is usually fixed, there can be considerable flexibility in locating new processing facilities, in the selection of the processing plant, and in blending the ore before and after processing.

Jan 1, 1983

By Robert J. Greaves

High-resolution seismic reflection profiling can be used to evaluate detailed struc¬tural and stratigraphic features of coal pros¬pects. Since most coal prospects are relatively shallow (less than six hundred meters deep), the vertical and lateral resolution of seismic data can be significantly improved by high sampling rates in space and time. The case study present¬ed shows the effective use of seismic data in evaluation of the Wyodak coal at a prospective coal gasification site. The data were used to map the detailed structure and thickness of the coal and to search for lateral discontinuities, such as pinchouts and. faults. An important find was a paleochannel cutting across the base of the coal seam, which was later confirmed by drilling.

Jan 1, 1983

By William H. McLemore

Geologists searching for carbonate rocks suitable for chemical uses traditionally have relied on extensive laboratory testing in order to locate strata or zones that might be suitable for mining. However, when considering the significant time and costs involved in sampling and performing chemical analyses, any exploration technique whereby fewer samples and analyses are needed would be of great value. In other words, if the exploration geologist could "zero-in" on select areas, considerable time and money could be saved. In general, the major-element chemistry of carbonate rocks is determined by the abundance of the minerals present. CaO occurs with CO2 as the mineral calcite, which is the primary mineral comprising allochems, matrix and sparry cement; MgO is found in high-magnesium calcite (many calcite fossil species contain appreciable amounts of MgO in solid solution), dolomite, and chlorite; iron occurs in pyrite and in limonitic stylolites, as well as in chloritic and glauconitic clay minerals; materials containing abundant Si02 are microcrystalline quartz (chest) silt-sized quartz, and clay minerals; and Al203 is found primarily in illitic, kaolinitic, and chloritic clay minerals. The presence or absence of these minerals determines the chemical composition of the carbonate rooks.

Jan 1, 1983

By Gary G. Grim

The reliable performance of the coal reclaim system is essential to the continued availability of a coal-fired electric generating unit. The control of fugitive coal dust within the areas housing the reclaiming equipment is necessary not only to minimize maintenance and clean-up costs, but is also a safety and health consideration. This paper describes the reclaim system control and dust suppression systems as initially installed, the shortcomings of these systems and the steps eventually taken to correct these shortcomings.

Jan 1, 1983