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By G. Kris Kapoor

Each new period of public concern, whether rooted in things political, social, economical, or technological, brings with it new words or phrases which highlight that new interest. With people's awareness of our rapid depletion of readily available energy sources and the enormous increase in energy .costs came the new, and now often heard, terms "energy intensive", "energy sensitive", and "energy conservation". Since its birth in 1926, Fuller Company had been directly associated and involved with energy intensive products and processes. We are located in the heart of the Cement Industry. Many of our products and processes are geared to the needs of the portland cement manufacturer, and a look at the inferno within an operating cement or lime kiln will certainly convince anyone that here is an energy intensive process. Fuller Company, then, has always been energy sensitive. Process kilns, hard rock crushers, tube and roller mills, fluid bed thermal reactors, pneumatic compressors and conveyors, material coolers - all are Fuller Company products utilizing or transferring large amounts of energy. Consequently, much of our success in the marketplace depends on how wisely we design and plan for efficient use of power and for conservation of each unit of heat available.

Jan 1, 1975

By R. C. Kellner

Duval Sierrita Corporation, a wholly-owned subsidiary of Duval Corporation, operates an 86,000 STPD copper-molybdenum concentrator near Tucson, Arizona. Shortly after production commenced in February, 1970, it became apparent that the reduction crushing system represented a limitation to reaching the design capacity of 72,000 STPD. The development work performed on the reduction crushers in order to first meet design capacity, and to subsequently increase production to 86,000 STPD is described in this paper. The Sierrita plant is a conventional three stage crushing sys- tem. All crushers were supplied by the Allis-Chalmers Corporation and consist of two 58 x 89 Superior gyratories, four 138b EHD hydrocones, and ten 384 hydrocones. Screening is performed prior to and subsequent to secondary crushing and in closed circuit with the tertiary crushers. Typical throughput rates and equipment sizes are presented in Figure No. 1.

Jan 1, 1975

By B. J. Huls

The commissioning of a Distributed Digital Control. System for the grinding circuit at Cuajone, was completed by mid August, 1985. Development of a successful strategy, excellent operator acceptability and the visual aspects offered by the display of the central console, improved mill throughput significantly. The inherent features of a digital system enhanced the flexibility in grinding control and allowed the mills and classifiers to be operated at maximum capacity. This paper discusses in detail the strategy development, the production restrictions encountered, and evaluates the overall performance of the digital control system. 1.0 Introduction In November 1976, the Cuajone Concentrator, located on the western slope of the Andes in Southern Peru, was commissioned to treat a nominal 41,000 TPD of ore. A systematic elimination of production restrictions has resulted in a continual increase of concentrator throughput to 48,700 TPD before the grinding control was in- stalled.

Jan 1, 1986

By C. Villa Diniz

It is proposed that battery grade Mn02 can be produced directly from a manganese ore from Azul Mine in Brazil, by leaching with HCI to remove heavy metals selectively. We are working to find a way of selectively separating Cu, Ni, Co, Pb and Fe from the resulting acidic manganese chloride solution, to detoxify it and produce marketable chloride solution. Chelating ion exchange resins are proving more promising for this separation than solvent extraction with commercially available reagents. Results from batch and column ion exchange tests that characterize the behavior of copper, nickel, cobalt, lead and iron are reported.

Jan 1, 1999

By S. Tan

In this paper, several commonly used computer truck dispatching criteria are evaluated. A computer-oriented truck dispatching and production simulator was developed to provide data for comprehensive cross comparison among the dispatching criteria. The definitions, primary considerations, characteristics, and performances of these dispatching criteria were investigated. From the simulation results, it was concluded that, in general, no one criterion can dominate all others. All basic dispatching criteria including minimizing truck waiting time, minimizing shovel waiting time, minimizing truck saturation, maximizing truck momentary productivity, or truck routes optimization provide a local optimal solution. To obtain a direct global optimization solution for this complex stochastic process does not appear to be likely. Therefore, the search for an optimal dispatching criterion that will fit all conditions may not be realistic. However, based on the simulation results of the mine operation, several dispatching criteria which have good potential to increase performance can be selected. It may be necessary to search for the best combination of these truck dispatching criteria for a given situation. For example, a truck flow measurement such as the truck clustering factor at shovels can be used as a switch parameter to change from one criterion to another. The values for the switch parameter at which actions should be taken to change the criterion can be established through simulation programs.

Jan 1, 1992

By Laszlo Valentyik

The wide scale acceptance of the heavy media separation is due to its simplicity and efficiency. The two most important variables of the process are specific gravity and consistency of the medium. The latter is a function of the settling rate of the media solids. The almost always present clay in the feed and conse¬quently in the medium acts as a stabilizing agent, and its optimum concentration varied between 3-4%.(1,2) Since polymers essentially perform the same function in oil well drilling muds - i.e. to suspend cuttings during drilling - as the fine clay in heavy media separation, this led to the investigation of whether polymers could be used in heavy media separation as supporting agents. During the first phase of the work, it was found that by the controlled addition of polymers, the stability of the heavy media increased without unduly increasing viscosity of the suspensions, thus yielding conditions for more effective and efficient separation. The results of the experiments were reported in a paper at the AIME Centennial Annual Meeting, March 1971.(3) This paper presents the results of the experiment carried out during the second phase of the work.

Jan 1, 1975

By James Donald Forrester

JAMES DONALD FORRESTER 32.1-EXAMINATIONS The field examination of a mineral deposit or mining enterprise requires a comprehensive effort to determine all natural and man-made factors bearing upon the problem to be resolved by the investigation. Therefore, the purpose to be served by an examination must be fully understood before the engineer assumes responsibility, and before actual field work starts. A clear understanding facilitates planning the approach to the project for maximum efficiency and thorough acquisition of information. It follows, of course, that the engineer has the necessary knowledge and experience to discharge satisfactorily the professional obligations attending the project. Some studies are in herently more complex than others, and the requirements of the problem are not always the same. Some examinations require the detailed investigation of large operating or nonoperating mines or, possibly, of mining districts; others involve more or less reconnaissance studies; and still others rela¬tively small undeveloped mineral occurrences. Likewise, the primary objective of some analyses may be the evaluation of a mineral deposit or a mining property, whereas in other projects the major objective may be guiding mining or drilling work in the discovery of new or hidden ore bodies and mineral-bearing structures. Thus, the possible range of any given examination may extend in varying degree through one, or more, of the following types of procedures: 32.1.1--GEOGRAPHIC ENVIRONMENT Studies of geographic environment should be made to ascertain the general physical situation in the area under consideration and to identify those correlative factors hearing on the, findings resulting from the field examination. This commonly will include determinations of: A. Location of the field area with respect to the state and county in which it occurs and, if feasible, a record of the township, range and section with reference to the principal meridian, and base line (or lines) that apply. For examinations in foreign countries, or in regions outside the continental United States, it is desirable that the field locality, in each instance, be identified with reference to the boundaries of some form of political entity essentially comparable in character to the divisions used in the United States. B. Distances from existing communities and related service centers, via: 1. Roads, both improved and unimproved. 2. Railroads. 3. Navigable waterways. 4. Airports. C. Topographic relief as it will influence the selection of 1. Pit site or positions of underground mine portals or shaft sites, including dump areas. 2. Mill site, including tailings disposal area.

Jan 1, 1973

By D. C. Sisti

A paper was presented during the 1970 SME Fall Meeting on the Stinson Preparation Facilities by representatives of Beaver Creek Consolidated Cool Company and Heyl & Patterson, Inc. This paper summarized a combined approach to development of a flow diagram and selection of cleaning equipment required to produce a uniform metallurgical coal at maximum recovery with special emphasis on sulphur reduction. These facilities were located in the Elkhorn. Coal Fields of eastern Kentucky and, in particular, the area of Wayland, Knott County, Kentucky, where approximately forty-five- million tons of Elkhorn No. 3 coal could he recovered. The facilities incorporated a Bradford Breaker for reduction of the ROM coal to minus 1-1/2 x 0, 6000 ton-raw coal storage, preparation plant, water clarification and thermal drying facilities, clean coal storage and a 4000 TPH unit train loading facility.

Jan 1, 1973

By Stuart R. Cotterill

Open cast surface mining requires blast hole drilling with many interesting facets in order to achieve mine planning forecasts. Interestingly, no single method or combination of theoretical hypothesis of mining economics is right for all conditions. On occasion mine planners introduce a project with little or no regard to drilling and blasting. Generally, drilling and blasting costs are a significant percentage of total mine overhead. One such drilling and blasting method which can be utilized to reduce overall mine expenditure is inclined or angle hole drilling. One must bear in mind, that angle hole drilling per-se mill not reduce costs, unless a set of required circumstances is met. An attempt will be made to detail when conditions of the mine design criteria dictate the use of angle drilling.

Jan 1, 1984

By J. J. Harrington

The pH control system at Kennecott Copper Corporation's Nevada Mines Division concentrator consists of two independent systems, lime dilution and lime addition. Lime dilution is accomplished in a mixing tank where slaked lime and water are introduced proportionately. The desired dilution of the milk of lime is determined by the electrical inputs provided by eight pH probes, one per grinding section. The inputs are averaged and applied to a time base generator. The summation output of the time base generator determines the proportion of lime and water that are to be mixed and applies this input to a voltage sensitive switching device. The switching device provides a signal to one of two relays which will add either slaked lime or water, dependent upon the summation output. The entire cycle is based on a two-minute repetition rate to allow for sufficient mix time. Responsivity is controlled by maintaining a limited maxi- mum solution level in the mix tank. Lime addition is controlled independently within each grinding section. The electrical input from the pH probe in a given section controls the solenoid valves which provide lime to each of the ball mills. The valves remain open within a time range capable of maintaining the pH of flotation feed at a given set point.

Jan 1, 1975

By R. R. Klimpel

In this first report, we present a preliminary model based on the simple binary sys¬tem of component B occluded in a matrix of compo¬nent A, for the case where fracture planes can pass with equal ease through A or B. By assuming that the volume fraction of B in AB in the overall matrix is small, which is realistic for many prac¬tical systems, the problem is reduced to a one-¬dimensional treatment which is conceptually easy to understand. The model was programmed for Monte Carlo simulation, and an analytical solution also developed based on the assumption of zero or one mineral fragment per particle. Preliminary ex¬perimental confirmation using a synthetic "mineral¬-host matrix" of known amount and size of B in AB is presented.

Jan 1, 1983

By L. Valentik

Many attempts have been made during the last forty years to evaluate the performance of gravity separation equipment, that is, the effectiveness with which light and heavy particles are separated. The most comprehensive treatment of the subject was made at the 1st International Conference on Coal Preparation held in Paris (1950) by Cerchar. The methods suggested by the Conference were accepted and very widely used in the last 25 years. This paper discusses an improved method of evaluation in the light of the now accepted standard presentation. The float and sink analysis of the product is presented on a Gaussian distribution curve, resulting in an easier visualization of the inherent difficulties of separation. The ogives of the distribution curve are then plotted, giving a quantitative measure of the deviation from perfect separation as an error distance instead of an error area. Illustrations of the new method are given both for gravel and for coal preparation, but the concept is valid and applicable to other types of minerals which are separated by gravity methods.

Jan 1, 1968

By Harold L. Lovell

The current interest in sulfur recovery from coal measures is indicated by a recent report prepared for the Public Health Service (1) It was noted that the concentration of pyrites to a product containing 42-48 percent sulfur should be relatively easy with present equipment. It was also pointed out that a utility potential exists for the high-grade iron concentrate which results as a by-product of the consumption of pyrites in the acid-making process. However, economics, marketing characteristics, location, transportation, pyrite levels and coal characteristics all strongly influence the feasibility of fostering industrial development of such processes. The extent of pyrite recovery and product quality is intimately related to pyrite particle size and its degree of liberation, a consideration usually given greater emphasis in metal ore preparation than in processing coals. Consequently, fine crushing to nearly 20 mesh probably will be essential for maximum practical processing. It appears that any process separating pyrites from a coal must involve a reprocessing of the normal preparation plant refuse, although some yields can be attained from certain existing operations as products from, a shaking table or a jig. Further, the existence of millions of tons of coal refuse cannot be ignored as a mined source of raw materials. The recovery of saleable products from such wastes, although untried on a large scale under current conditions, not only offers a realistic source of sulfur but also would achieve a secondary refuse with the minimal contents of substances which incite and propagate the burning of organic and inorganic combustibles. These silicate materials, thus beneficiated, also offer some potential for economic utilization. Some significant tonnages of pyrites have been produced from coal measures in the past, but the experience was, in general, not consistent with current coal preparation practice. The processes involved did not include cyclones and heavy media; nor were they carries out under the sociological environment concerned with pollution as exists today.

Jan 1, 1967

By William E. Foreman

Editor's Note: For purposes of uniformity throughout this book, Coal Preparation, 5th Edition, the editors have advocated the use of the U.S.A. Sieve Series of testing sieves (see Table 6-2) as the testing sieves of modem choice. The adoption and use of the U.S.A. Sieve Series and its forerunner, the Tyler Standard Screen Scale, has for over seventy-five years introduced uniformity into reports; has simplified the comparison of results; and has provided control for operation of modem coal preparation circuits. While a full explanation of the differences, and more importantly the similarities of these two measuring systems cannot be stated here, it is felt that a brief clarification of terms is in order. The difference between the U.S.A. Sieve Series and the Tyler Standard Screen Scale Sieve Series is the identification method. Tyler Screen Scale sieves are identified by mesh designation with the width of opening varying by the square root of two, or 1.414 times the width of opening in the previous sieve. The U.S.A. Sieves are identified by openings in millimeters or microns and also arbitrary numbers which do not necessarily mean the mesh count; this series uses width of opening variations in the order of approximately the ratio of the fourth root of two, or 1.189. Tyler Standard Screen Scale and U.S.A. Sieves can be used interchangeably, and to avoid confusion the nameplate of all Tyler Screen Scale sieves show the U.S.A. Number, while all U.S.A. Sieves show Tyler Screen Scale mesh equivalent numbers on the nameplate. INTRODUCTION Sizing is the process of separating mixed mineral particles into groups of particles all of the same size, or into groups in which all particles range between definite maximum and minimum sizes. This chapter applies the modem mechanical screen and the liquid-solid cyclone (hydrocyclone) to the process of sizing solid particles as applied to coal preparation. Screening is a mechanical process that separates particles by size. Modem coal preparation is made possible by efficient sizing. Sizing of coal is defined in terms of the opening through which an individual particle will or will not pass, or as two openings, the larger of which passes the particle and the smaller of which retains the particle. Screening accomplishes sizing by passing coal of a wide range of sizes through a series of screens, each of a decreasing size. The individual screen discharges are then directed into different screen products for subsequent sale or processing. Screening in modem preparation plants is done for the following reasons: 1. Removal of fine coal before a size reduction step. 2. Size separation of the coal into a coarse and fine fraction for sized products or for processing in coarse and fine coal circuits. 3. Recovery of heavy media from heavy media coal cleaning circuits.

Jan 1, 1991

By Christopher D. Henry

Environmental geologic maps of the Wilcox and Jackson-Yegua lignite belts of the Texas Coastal Plain delineate land areas on the basis of their natural characteristics. Criteria used to define map units include substrate, soil, topography, geologic process, vegetation, and land use. The maps are useful in planning and reclamation of lignite mines and in meeting the requirements of State and Federal surface mining laws. Specific applications include identification of land capability, recharge areas and geometry of aquifers, flood-prone areas, areas that may qualify for prime farmland status, and other areas sensitive to lignite mining.

Jan 1, 1982

By N. S. Tanious

The need to provide better mine roof support and control in longwall tailgate entries prompted the Bureau of mines to search for a replacement product for wood cribs. Their search isolated steel-fiber-reinforced concrete (SFC) as the most effective replacement. Through successful laboratory and underground mine tests, handmade SFC cribs proved to be a viable and more effective roof support system. However, to ensure wider usage, U. S. Steel Mining Co. initiated a joint development and evaluation program with Burrell Construction Company in order to mass produce SFC blocks of reasonable dimension, weight, and cost. Small specimens and full-size cribs were evaluated during this program to determine their compressive strength and post failure characteristics. After considerable testing and adjusting of various concrete mixtures, a final formulation for the SFC crib blocks was selected. That formulation permitted the construction of SFC cribs possessing a nominal crib strength of 3200 psi (22.1 x 106 Pa) and a nominal modulus of elasticity of 1.0 x 106 psi (6894.76 x 106 Pa). These SFC cribs can support from 3.5 to 14.5 times as much load as a wood crib, depending on the size of the wood crib being replaced. Both laboratory and limited mine tests, conducted by U. S. Steel Mining Co. have shown the SFC crib to be an economical and effective means of roof control.

Jan 1, 1984

By D. W. H. Su

"This paper presents the results of a comprehensive study conducted by CONSOL Energy, Marcellus Shale Coalition, and Pennsylvania Coal Association to evaluate the effects of longwall-induced subsurface deformations on the mechanical integrity of shale gas wells drilled over a longwall abutment pillar. The primary objective is to demonstrate that a properly constructed gas well in a standard longwall abutment pillar can maintain mechanical integrity during and after mining operations. A study site was selected over a southwestern Pennsylvania coal mine, which extracts 1,500-ft-wide longwall faces under about 600 feet of cover. Four test wells and four monitoring wells were drilled and installed over a 125-ft by 275-ft centers abutment pillar. In addition to the test wells and monitoring wells, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the 1,500-ft-wide longwall panels on the south and north sides of the abutment pillar were mined by. To evaluate the resulting coal protection casing profile and lateral displacement, three separate 60-arm caliper surveys were conducted. Prior to the longwall panels being mined by, a number of 3D finite element simulations were conducted to estimate subsidence at the surface, coal pillar pressure increases, the resulting coal protection casing profile and displacement, and the vertical and horizontal displacements in the four monitoring wells. Comparisons of the pre-mining 3D finite element simulation results and the surface/subsurface/underground instrumentation results show that the measured test well and IPI casing deformations and profiles are in reasonable agreement with those predicted by the 3D finite element models, and that the measured surface subsidence and pillar pressure are in excellent agreement with those predicted by the 3D models, which serves to validate the 3D finite element models. Parametric studies employing the validated 3D finite element models demonstrate that larger coal protection casing thickness is expected to have little effect on the lateral deformation, although it may reduce the magnitude of casing plastic deformation, and under deeper cover (~1,100 feet), lateral casing deformation is expected to be smaller, although larger plastic casing deformation may be present near the seam level. Also, evaluation of various casing and cementing designs using the validated 3D models clearly indicates that, when all casings are grouted to the surface except the intermediate and production casings, the intermediate and production casings show little deformation and no plastic strain. This research represents a very important step and initiative to utilize the knowledge and science obtained from mining research to improve miner and public safety as well as the safety and health of the oil and gas industries"

Jan 1, 2017

By Charles A. Beasley

Coal conversion to electricity or to substitute natural gas requires a significant quantity of natural and human resources including, in addition to the coal resource base, land, water and the construction and operating labor force. Each method of coal conversion has its advantages and disadvantages relative to conversion efficiency, preferred method of resultant energy transportation, resources consumed, and impact on the environment. Regulations which have been passed in recent years to maintain or restore the pre-project environment can add significantly to the capital and operating costs of both a conversion facility and its associated mine.

Jan 1, 1983

By Francois E. Heuze

The mined geologic burial of high-level nuclear waste is how the favored option for disposal. The underground repositories must keep the waste away from the biosphere for very long times - several thousands to tens of thousands of years. Also, access must be maintained to the vaults for several tens of years, so that the waste can be retrieved, if necessary. Both the excavation of the underground chambers, and the radiogenic heating will disturb the rock mass. The overall rock mechanics problem is to understand and predict the processes associated with these perturbations, and their impact oh the isolation and containment of the waste (3)**. The specific rock. mechanics issues which have been identified for the three candidate hard rocks (basalt, granite, and tuff), are summarized in Table 1. The table also indicates the level of adequacy of our knowledge in the areas of the various issues. Such an evaluation is consistent with the general consensus of the rock mechanics profession, as explained in several key reports and publications (1 to 11). The main shortcomings of today's rock mechanics for waste repositories can be summarized as: ? lack of resolution for remote mapping of fractures in rock masses ? great difficulty in testing large volumes of rocks to determine their mechanical properties.

Jan 1, 1981

By Sidney V. Gold

Should Gold Producers Hedge Their Positions Through : Sales on Forward Markets? Purchases of Put Options? Sales on Spot Market? Forward Markets Assumptions 1. Producer has a known amount of Gold to sell in year ahead. 2. Effect on price is the same whether sold Forward or Spot Market. 3. None of us have knowledge of Future Price Trend. 4. Contange Market prevails in which Forward price premium is approximately equal to rate of interest.

Jan 1, 1983