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By R. H. Mullennex

Application of depositional analysis concepts is becoming an ever-increasingly more important and more useable tool in exploration and development of coals in the Appalachian basin. Over the past decade, a rather large number of studies, papers, and publications have addressed various aspects of depositional environments of coals and, to some extent, applications to development. As would be expected as regards a subject so complex as Pennsylvanian sedimentation in the Appalachian basin, certain academic studies have produced conclusions at variance in some aspects to those of other studies. Overall, however, there has been a building- block progression and general refinement with time of understanding of the depositional settings and other factors controlling Appalachian coal distribution, quality, and other minability parameters. Most attempts to explain coal seam characteristics have revolved around a basic deltaic model. Some have attributed certain seam attributes to upper delta plain deposition, other attributes to transitional-lower delta plain settings, and yet others to lower delta plain environments, and so on. While these approaches have provided valuable insight into some general coal characteristics, they are somewhat incomplete and are, in a sense, too broad for specific mine-scale applications. Further, it is apparent that in order for widespread peat accumulation to occur, there must be a drastic decrease in the energy of the depositional system and amount of sediment being brought in, compared to the active deltaic and coastal processes responsible for deposition of the large volume of clastic sediments that dominate the Pennsylvanian system of the Appalachians. Consideration of this fact implies that peats (coals) may not necessarily reflect depositional settings that are directly coincident with those associated with adjacent rocks. Cecil and Englund (1985) address this point, and quite correctly state that "the primary controls on major stages of peat formation are allocyclic processes involving paleoclimate, eustatic changes in sea level, and tectonics." While this statement is inarguable, it does not negate the importance and usefulness of depositional analysis in predicting reserve characteristics that may impact mining and marketability.

Jan 1, 1986

By J. S. Whatley

The properties, origin and industrial uses of kaolin clay are briefly reviewed. The general waterwashed beneficiation process is described. Yost aspects of filtration and solids-liquid separation as practiced in the kaolin industry are mentioned along with devices that are currently in the developmental stage. The paper focuses heavily on the well known art of rotary vacuum filtration, including general construction and operating details. Devices under investigation that might be used to mechanically or electrically dewater clay slurries to higher cake solids levels than can be achieved with rotary vacuum filters are described briefly.

Jan 1, 1986

By P. J. Bethell

In the froth flotation process the detrimental effect of slimes on the froth flotability of valuable minerals has long been known.1 Work by Aplan2 on the froth flotation of coal has shown that the presence of clay slimes causes loss in flotation selectivity, and recovery of combustibles. Obviously then the presence of clay slimes to any great extent in the froth cell feed in a coal preparation plant is undesirable. This problem is exacerbated in plants treating raw 600 um (28#) by zero material due to the variation in flotation with size. The net effect of this phenomenon in a bank of cells treating raw minus 600 µm (28#) material s that by the time adequate flotation of the coarsest size fractions has occurred the finer sizes are already producing undesirable high ash material, which often leads to unacceptable overall quality. Reduction in aeration rate and/or chemical addition to combat this, further decreases the flotation rate of the coarsest fraction leading to heavy losses of coarse low ash coal to the tailings. The above mentioned characteristics formed a key aspect of the fine coal circuitry design at Elk Run Coal Company in Sylvester, WV. The plant was designed to produce compliance steam coal (less than 1.20 lbs. S02/million b.t.u.) Desliming ahead of the froth flotation was included, as the slimes in the plant feed were clay rich, had very high ash levels, and low potential recovery. Lab testwork had also shown that poor selectivity would be expected if raw minus 600 um (28#) material was froth floated.

Jan 1, 1986

By M. A. Greenwood

The total value of coal, FOB mine, consumed in the United States was $21 billion in 1985. Roughly $6 billion was spent to transport coal from the mine to the consumer by rail. This indicates the impact railroad transportation has on the competitiveness of U.S. coal as an energy resource. Actually, this is just the tip of the iceberg. When you consider the largest U.S. reserve of coal, the Powder River Basin, which is possibly the lowest cost coal in the U.S., or maybe even the world, the transportation cost is the overriding factor in developing competitive pricing. Rail transportation costs from Powder River can be multiples of 2, 3, or even 4 times the cost of coal FOB mine. About sixty percent of all U.S. coal is shipped by rail. In the case of Powder River Basin coal and many other reserves there are no current alternatives to rail. Are there feasible alternatives to rail transport?

Jan 1, 1986

By Edwin H. Bentzen, Immo H. Redeker

Important industrial minerals are separated and concentrated by froth flotation by industry today. The following descriptions are presented as an overview of the methods employed to separate and recover a few of these industrial minerals. The minerals described in this section of the book are not, by any means, the only important minerals treated by froth flotation. Other minerals, such as calcite, kaolin, wollastonite, rare earths and vermiculite were not included, primarily due to the confidential nature of the information held by the Minerals Research Laboratory and the Colorado School of Mines Research Institute. Flotation of nonmetallic minerals is sometimes viewed as alchemy. However, the art is, in reality, based on sound chemistry, experience and a little luck in the treatment of new ores. In the flotation of nonmetallic minerals, as opposed to base metal sulfides, highly specific treatment conditions are required to accomplish separations. The presentation of the treatment of each of the minerals described was outlined as follows: DEPOSITS PROCESSING SPECIFICATIONS FLOWSHEETS (in some cases) A presentation of the factors, often critical, which must be carefully investigated to accomplish successful flotation of nonmetallic minerals is presented in the section on Sulfonate Collectors, elsewhere in this volume.

Jan 1, 1986

By Dennis Z. Mraz

Subsidence profiles over Saskatchewan potash mines exhibit forms which cannot be explained by existing subsidence models. The subsidence is affected by bridging of competent rocks. A modification of the theory can explain the observed displacement of subsidence profiles due to bridging. An unusual shallow secondary subsidence trough has been observed extending two to three kilometers outside the primary subsidence. The secondary subsidence is explained as an elastic compression inresponse to a drop in pore water pressure in the vicinity of the caving zone. The concept of pore water pressure may lead to a safe extraction limit for Saskatchewan mines.

Jan 1, 1986

The main goal of this paper is to present readers with recommendations for choosing coaxial cables appropriate for mining applications of Time Domain Ref 1 ectometry (TDR) to monitor rock mass movements. Prior to discussing the recommendations, mining applications are illustrated with examples and the operating principle of TDR is discussed briefly. Items that affect the result of the monitoring system performance include the coaxial cable selected, the grouting material used, and the installation procedure.

Jan 1, 1986

By T. Cyrul

The Polish underground mining has its long lasting tradition. High production of coal, that has recently been approaching 200 milion tons per year, put this small country among the bigest world producers of coal. To achieve such a high production, which mainly originate from very unfavourable mining and geological conditions, Polish scientists and engineers have to introduce new and original solutions to the mining practice. Many of the solutions on mining methods, ventilation, stability, subsidence etc., have had the world wide reputation, however, insufficient translations from Polish cause , that many of the recent Polish mining achievements are not known to foreign specialists.

Jan 1, 1986

By P. D. Chamberlin

Agglomeration for the heap leaching of gold and silver ores can be defined as the process of attaching fine ore particles (less than 100 mesh) to coarser particles so the fines are immobilized and uniformly distributed throughout the heap, thus making the heap more porous and uniformly permeable to the flow of a leaching solution. Agglomeration techniques and equipment to be described include drum and disc agglomerators, stockpile and belt agglomeration, and the use of vibrating deck and reverse running conveyors.

Jan 1, 1986

By W. Z. “Ben” Wu

The investigation provides a method of efficiency evaluation among several kinds of tools employed to cut different types of rocks. A ballistic test stand incorporated with a modified Hopkinson bar was used to simulate a percussive drilling tool. An Apple IIe microcomputer was employed for high speed data acquisition and numerical analysis. A newly developed method for remote monitoring the rock-tool interaction, including contact force, bit penetration and energy transmission,is presented in the paper. Theoretical predictions and experimental results appear in faily good agreement

Jan 1, 1986

By W. D. Hausel

Archean supracrustal rocks of the South Pass greenstone belt of western Wyoming have been the State's most prolific source of gold and iron ore. Actual gold production statistics are incomplete, but as much as 400 to 500 thousand ounces may have been mined with some silver and tungsten as a by-product. Iron ore was also mined from the greenstone belt for 22 years, and production totaled more than 90 million tons. Immediately south of the exposed greenstone belt in the Oregon Buttes area, Tertiary boulder conglomerate, which has been eroded from the granite-greenstone terrain, may contain a gold resource of 28.5 million ounces (Love and others, 1978). The amount of gold placered from stream alluvium derived from these Tertiary conglomerates is unknown.

Jan 1, 1986

By Finn Ouchterlony

INTRODUCTION Much of present fracture toughness testing con¬cerns chevron notched specimens (Newman Jr., 1984) since these, in principle, require neither fatigue precracking nor more registration than failure load to determine fracture toughness. Two such specimens which can be made from diamond drilled rock cores with minimal machining are the Short Rod (Barker, 1977) and the Chevron Edge Notch Round Bar in Bend¬ing or CENRBB Specimen (Ouchterlony, 1980). Even if the precracking property is especially valuable for a material like rock, practice has made the relative advantages of these chevron notched specimens much less apparent (Ouchterlony, 1982; Ouchterlony and Sun, 1983). Enough remains, however, to have the Commission on Testing Methods of the International Society for Rock Mechanics (ISRM) focus on them as standard configurations in a "Suggested Method for Determining Fracture Tough¬ness of Rock Material", which is in preparation. This paper presents material which supports the ISRM effort: 1. An experimental compliance calibration of the Chevron Bend (CENRBB or CB for short) and re¬sulting formulas. 2. Specimen tolerances, evaluation formulas, and loading rate requirements relating to both Short Rod and Chevron Bend Specimens of suggest¬ed standard proportions. 3. Some fracture toughness values obtained with the Chevron Bend Specimen. This material is mainly based on two reports (Ouchterlony, 1984 and 1985). CALIBRATION OF THE CHEVRON BEND SPECIMEN Preliminaries The specimen and basic notation is shown in Figure 1 together with a straight notched variety (SECRBB). Subscripts c and s are sometimes used below to distinguish between them. Assuming linearly elastic conditions the load point compliance [ ]

Jan 1, 1986

By ev, Ze&apos Reches

The growth of networks of shear fractures is explored in a series of experiments with samples of wet clay. The samples are subjected to plane strain deformation in a rigid apparatus. The individual fractures observed on the upper surface of the clay samples grow longer by three mechanisms: in-plane propagation, off-plane propagation and coalescence. New, active fractures cut and displace older, less active ones. The lengths of individual fractures display lognormal distribution in most cases and power distribution in fewer. The calculated length parameters in the experiments, as well as in three field cases discussed here, suggest that the fundamental parameters in fracture analysis are the normalized cumulative length and the length of the shortest fracture measured.

Jan 1, 1986

By A. M. Elmherig, M. R. Sunu, R. N. Singh

The presence and orientations of fractures and discontinuities in rock masses exposed in a surface mining excavation are likely to have a great influence on both slope stability and blasting efficiencies. The classification of rock materials requires detailed investigations which are of interest to the design engineer. In designing a safe mining excavation, an engineer must take a number of decisions regarding face support and orientation based on the evalu¬ation of local strength and structural conditions encountered. The description of rock masses requires information additional to the properties of the rock material, discontinuities and other characteristics of engineering importance. Such information involves the acquisition of the following data: The description of the rock mass with reference to major geological structures. The orientation, nature, spacing and persistence of discontinuities. Degree of weathering. A critical review of rock mass classification systems and their application to surface mine excavation design and stability analysis is presented. The field investigation techniques for collecting rock mass data are described together with the techniques of analysis and presentation of data. Laboratory tests are carried out to determine intact rock strengths and deformation parameters of rock. The paper presents two case studies from the British hard rock surface mining industry to illustrate the application of the rock mass classification systems to stability analysis and excavation design.

Jan 1, 1986

By Francis F. Pitard

North America had an Important role in the early development of sampling theories. Unfortunately many progressive ideas were soon frozen into a series of guidelines based on the philosophy that "honest sampling only requires good judgment and practical experience". Such a philosophy appeared to be good enough In the early age of the mining Industry; however, it became quickly necessary to find new approaches. During the last thirty years, Pierre Gy's sampling theory provided tremendous breakthrough in the comprehension of this new science, nevertheless went unnoticed in North America. Sampling always generates complex problems and as the philosopher and mathematician Descartes suggested: "A complex problem can often be dissociated Into a series of several simpler problems, only then you try to solve those one by one". The only way to solve sampling problems is to consider each component of the overall sampling error: components of a continuous model such as long-range quality fluctuations, periodic quality fluctuations, weighting fluctuations; components of a discrete model such as materialization errors, delimitations errors, extraction errors, fundamental errors, grouping errors, and segregation errors. PAST AND CURRENT PRACTICES Many sampling methodologies have been developed, improved, and standardized during the first half of this century. Accordingly, sampling equipment has been proposed, selected, and used by standards committees. Today, there is a tremendous variety of sampling methodologies and corresponding tools offered to anyone with limited experience in sampling and it is very easy for a chemist, metallurgist, geologist or miner to spend considerable money in equipment transgressing the most basic rules of sampling correctness. Sampling stations that never worked properly in modern plants often cause engineers to abandon them and return to a primitive form of grab sampling.

Jan 1, 1986

By J. S. Spivey

We in the coal industry, especially in the State of Illinois, put tremendous emphasis, including time, money and effort, into on-the-job training. The results of such training and safety have been tremendous. For example, in 1981 Illinois was the first major coal producing state in the history of coal mining to have zero mine-related fatalities. And in 1985, I am very proud to say, we had the second best record in the history of coal mining, with only two fatalities. Obviously, one fatality is one too many. Our goal is, has been and will continue to be to strive for excellence. It is sad, however, that in 1981 while were were celebrating zero fatalities in the workplace, there were 21 fatalities that occurred off the job. Thus, it has become a classic American story. Success with safety has been found in the workplace, but training and preparation to prevent accidents away from the job site have almost been ignored. Accidents are the leading causes of death in the United States for all persons age 1 thru 38, and are the fourth leading cause of death for people of all ages. Every single day, on the average, more than 290 Americans are killed in accidents - a rate of one every five minutes. The leading cause of fatal accidents in the U.S. is motor vehicles. And the number two cause is home accidents. A staggering statistic is that people are being killed off the job at a rate of about 9 to 1 over those on the job.

Jan 1, 1986

By H. L. Ford

Flocculant testing should be initiated for economic or performance reasons. When the decision has been made to test, the laboratory can provide valuable information concerning the various products under consideration. Properly conducted laboratory tests can determine: 1. If two flocculants are needed to achieve clarity or density. 2. Ease of mixing. 3. How quickly the material goes into solution. 4. Stability of prepared f locculant solution. 5. Stability of the floc formed. 6. Amount of mixing required for proper floe formation. 7. Optimum flocculant concentration. 8. Optimum pulp density. 9. Approximate location of the point of addition. 10. Single or multiple addition points. When a flocculant shows promise in the laboratory, a plant test should be scheduled. During the plant trial, arrange for normal conditions and start testing with a crew that is most familiar with the unit operation where the flocculant will be applied.

Jan 1, 1986

By Luis Yacher

CONTAC Engineers is a Chilean based company which works on process control and automation, principally for the minning industry. Jointly with other local and international engineering firms, CONTAC has participated in most of the last expansion and modernization plans being carried out at the Chilean pinning industry. At presente, CONTAC is involved on a research and development plan for the design and implementation of new instrument and process control procedures for mineral process automation. One of these efforts is the design of an ore size analyzer for coarse ore being transported over a conveyor belt. A feasibility and prototype study was made at a SAG Mill Plant and currently a high resolution, high speed analyzer is being developed. It will became available on early 1986.

Jan 1, 1986

By R. Addison

Boom, boom, boom, boom. The staccato beat rings out across the bush; the stamps are at work - slowly pulverizing gold-bearing ore for a patient, grizzled prospector. This is the State Battery near Marvel Loch - a tiny (capacity: 25 ton/day) gold plant operated by the Western Australian government. It is one of many such plants located in remote corners of Western Australia and the Northern Territory - miniature custom mills operated for the benefit of prospectors and small mine operators. These State Batteries, so called because they are operated by state governments and because the principal item of machinery in the plants are stamp batteries, are fascinating anachronisms: throwbacks to times long past, to a century ago, to the hard and heady existence of gold rush days.

Jan 1, 1986

By S. Kesler

Rössing Uranium Limited has operated since 1976 a large open pit uranium mine and extraction plant at a remote site in the Namib desert, South West Africa/Namibia. The geology (Berning, I., et al. Economy Geology) and the technical aspects concerning mining, grade control and metallurgy have previously been described (Rössing Uranium, Mining Magazin and Whyllie, R.J.M. "Rössing Uranium reaches rated production", World Mining). The improvement of leach 'extraction has been reported in 1984 (Kesler, S.B. et. al. "Uranium extraction at Rössing") and the installation of a central process control system has been described (Kesler, S.B. et al. "The introduction of a central process system at Rössing"). At the beginning of 1983 a decision was made to develop a computer system for metallurgical plant optimisation which included mass and volumetric balances, analytical assays for up to 5 chemical elements and the costs for the major consumables. Within 10 months this computer system was developed and implemented. A large number of test runs were made and computer studies were undertaken. The metallurgical division now has a scientific tool for production; planning for actual comparison with plant results and for strategic investigations and decision making.

Jan 1, 1986