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By Josef J. Schwegel

The first vertical shaft lime kiln operating according to the parallel-flow regenerative principle was developed and built in the nineteen-fifties by Schmid-Hofer in Austria. Upon proving this concept of calcining or "burning" limestone to be very energy efficient for the production of good quality lime, Maerz Ofenbau AG of Zurich, Switzerland was in 1965 licensed for the design detailing and construction of these kilns. The first regenerative shaft type lime kiln outside of Austria was built in 1966 and through close co-operation with customers and their operating personnel, the advanced technical developments of today's kiln designs were accomplished. At present approximately 190 kilns of this type in capacities ranging from 60 to 700 short tons per day have been built or are under construction throughout the world in highly industrialized as well as less developed countries.

Jan 1, 1981

By K. J. Stanaway

Environmental pressures on waste disposal are forcing pigment producers to use higher content TiO2 feedstocks with lower levels of trace elements. Despite this, 50% of the worlds TiO2 comes from ilmenite concentrates with only 37 -54 % TiO2 An industry growth rate of 25 % in the next ten years combined with trends to diminishing resources and lower grades for rutile (95 % TiO2) and leucoxenized ilmenite (55 to 90% TiO2) mean that unless new discoveries are made soon, the industry will become even more reliant on ilmenite. A hypothetical ideal feedstock is presented and strategies to obtain it are suggested. Reasons for some of the mineral specifications are given.

Jan 1, 1994

By Jon C. Jenkins

In order to plan the most efficient mine installation, a company should take advantage of all available information and tools. One of the first factors of a coal reserve that needs to be determined as accurately as possible is the quality of coal the mine will have access to during the life of the installation. With the aid of many types of well logs and computor analysis, we are investigating several methods of log correlation to determine such data as moisture, ash, sulphur, and BTU on an in place basis. It may be possible to determine this data more accurately in this manner than by using diamond drill cores for analysis and thus allow for a more profitable mine installation. The production of an underground mine is based on many factors, two of these being roof control and line water, where present either in the roof or coal seam. Using many of the same logs obtained from reserve and active mine areas, we have attempted to determine roof and floor characteristics such as strength, lithology, and moisture properties. Using data obtained from this program, we will make comments on possible length of bolt to be used, possible mining width, and pillar size as they would pertain to these reserves and active mine areas.

Jan 1, 1969

By R. W. Fedors, S. T. Green, F. T. Dodge, D. B. Walter

Spatial and temporal temperature variations in a high-level radioactive waste repository drift can give rise to moisture transport within the drift. Knowledge of this moisture transport may be important to assessing the potential for corrosion of all metallic components in the drift. The model presented here shows one approach to simulating evaporation, transport, and condensation of water in large underground openings using a framework based on computational fluid dynamics. Simulation results that explicitly model water and latent heat transport are presented.

Jan 1, 2004

By J. C. Agarwal

A significant portion of the, coal mined by U. S. Steel is beneficiated to upgrade the quality of the resultant coke to meet blast-furnace requirements. Primarily because of degradation from modern mechanized mining methods, a considerable quantity of the coal to be beneficiated is in the 1/4-inch by 100-mesh size range. In the cleaning plants, this coal is usually cleaned on concentrating tables and then mechanically dewatered in solid-bowl centrifuges to 9 to 14 percent water. At some plants, to further decrease the amount of water shipped with coal, and to improve the coking characteristics of the coal at its destination, mechanical dewatering is followed by thermal drying. At U. S. Steel's-Alpheus preparation plant at Gary, West Virginia, approximately 50 percent of the total coal produced is in this fine size range, and two fluidized-bed dryers are used for the thermal drying step. The two fluidized-bed dryers are 14 feet in diameter and were designed by the Dorr-Oliver Company. Although the original design called for a rate of drying equivalent to 37 tons, of moisture per hour, presently they are removing twice that amount. This paper describes, the major problems encountered' in operating these dryers at the present, high capacities and how they were overcome.

Jan 1, 1963

By H. V. S. Tingley

My topic today is future trends in compensation for the mining industry. I seldom get the chance to speak about a subject of such immediate interest to an audience, so I would like to make the most of this opportunity by telling you that everybody in this room will become rich beyond his wildest dreams in the next few years. I would like to open my talk that way, but in compensation, like everything else, there is a great gap between dreams and reality. Back to reality. When we talk about compensation, we?d better define our terms because the compensation is really an umbrella for five basic types of payment made to management personnel. Slide 1 identifies these elements of compensation.

Jan 1, 1980

By A. Cordonnier, Ch. Obry, R. Evrard

In spite of the large annual expenditures and the vast field of activity covered, it cannot be said that many new grinding machines have actually come to light and modified the existing market for more than half a century. Manufacturers have mainly made advances in increasing machine sizes, efficiency and reliability, and in machine automation. The relatively recent emergence of roller presses is the only exception to this homogenisation of machine ranges. The development of roller presses in pregrinding has shown the advantages of compression grinding over the ball mill from the power consumption point of view. But classical roller presses still have maintenance problems due to the high grinding pressure. The FCB Research Centre has carried out much work in this field and in particular has studied the advantages of this process in pregrinding and integral grinding. These researches lead to the development of two new compression grinding machines. The first one, HOROMILL®, presented for the first time on the 8th European symposium on comminution at Stockholm, finds its application in the field of fine to very fine grinding in dry process. The second one, RHODAX®, presented at INTERMAT in Paris, covers the field of secondary and tertiary crushing and the first stage of grinding for most of the minerals in dry or wet process. Its high reduction factor permits to do with only one machine the work realised today with two or three crushing/milling stages. These two complementary machines offer a wide range of combination summarised on [Figure 1].

Jan 1, 1995

By John B. Squyres

The purpose of this paper is to describe certain features of the uranium deposits of the South San Juan Basin, and to suggest a mode of origin for the deposits which is consistent with the data. A series of photographs is included at the end of the paper to illustrate the nature of the ore bodies. Since the general geology of the Grants Region is well described in the literature, it will be only briefly reviewed, and the time will be spent instead on the morphology, spatial relations, and geochemistry of the ore deposits. Part of this material is original, but data and ideas have been taken from a variety of sources, including the literature and the personnel of the USGS, the AEC, and many of the operating companies of the South San Juan Basin. I gratefully acknowledge these sources. The accuracy of the data and the conclusions presented here are my own responsibility, however.

Jan 1, 1974

By James S. Falcone

Soluble sodium silicate materials have well known applications in flotation for desliming, selective depression and corrosion control. Recent advances in the understanding of the complex polymeric nature of silicate solutions using NMR spectroscopy, combined with our studies of the effects of polymeric silicate anions on metal ion activities in solution, oxide mineral surface charges and surfactant adsorption on clays are related to beneficiation processes. The results of these studies indicate the sodium silicates can be used to cause a solution chemistry and particle surface charge characteristics favorable to enhanced effectiveness in typical ore beneficiation systems.

Jan 1, 1981

By R. Gunda

Due to the rapidly increasing production rates and deepening of mine working areas, there is a drastic rise in the number of thermal issues to be addressed for maintaining a safe mine environment. As high temperatures and humidity in underground mines could affect the health and performance of workers, and ultimately the production rate, it is necessary to provide a properly controlled safe environment. The backfilling of stopes in metal, non-metal mines results in different thermo-physical properties for the hanging, side and foot walls, modeling of which is not provided by any existing mine climate simulation software. This paper presents the modeling of such a single stope using the MULTIFLUX (MF) software, developed at the University of Nevada, Reno. A special case is presented in this paper, where a case study from the Homestake mine in the US with a drift and ramp connected to a stope with high Virgin Rock Temperature (VRT) and various spot heat sources is modeled in MULTIFLUX and CLIMSIM, and the results are compared against each other. Another case is presented in which the stope of the previous case is modeled with walls, each having a different set of thermo-physical properties. These results are compared with the former results to analyze the effect of anisotropic properties.

Jan 1, 2011

By Miguel N. Herrera, Abbas H. Mirza, Fiona M. Doyle

The standard test methods used to determine the pyrite content of coal and mineral wastes, and their propensity to release acidic drainage, are critically reviewed. In addition to analysis of total sulfur by combustion, test methods using selective oxidation of pyrite by HNO3 and H2O2 are available. The oxidation kinetics of pyrite vary appreciably from sample to sample, and it is difficult to ascertain whether complete dissolution has occurred in heterogeneous materials. The reliability, reproducibility and suitability of different standard test methods were studied, using well characterized ore and coal pyrite samples. The kinetics of pyrite dissolution were also investigated. The results are discussed in terms of the fundamental chemical and physical characteristics of each sample, and the implications for waste characterization are considered.

Jan 1, 1992

By E. A. Twichell

An entirely new concept in the effective utilization of magnetic, energy has resulted in a major break-through in the design of magnetic separation equipment. One of the first applications of this concept has resulted in the development of a Permanent Magnetic Wet Drum Separator with strength .and operating characteristics equal to Electro Wet Drum Separators. Prior to this development when strength and adjustability were required, electro wet drums were specified even with all their drawbacks. The electros, by nature, are subject to coil failure or burnout, over-heating and loss of strength, high power consumption and generally high maintenance. Now the high strength and the adjustability, formerly the exclusive property of electros, has been engineered into permanent wet drum separators. These units combine maximum field strength in the separation zone with strength adjustment to suit changing conditions. Adjustment can be effected while the drum is in operation without stopping either the feed or the drum.

Jan 1, 1967

By Weiguo Xie, MARK LAPUTKA

The pyrometallurgical industry plays a vital role in producing metals for our modern life. With growing demand for metals and declining grade of mineable ore, innovations become critical for many mining companies. This has given rise to the need for a review of recent improvements to the pyrometallurgical industry in terms of analytical measurement techniques, process and equipment improvements, and computer-based modeling/simulations. Because many of these innovations tend to be applied to a wider scope of metals, not restricted to a specific metal, we studied the broad applications of many improvements to a wide range of metals. We found that the challenge of a lack of robust measurement techniques under high-temperature conditions within a furnace hinders optimization of a pyrometallurgical process. Some future opportunities in the pyrometallurgical industry on analytical measurement techniques, computer modeling, and processes and equipment were also outlined and discussed.

By D. Bessinger, J. Nell

The electrical conductivity of rutile was optimised as a function of time, temperature and gas composition. These optimised conditions were used to treat rutile/zircon feed prep concentrate samples from a South African heavy minerals producer, prior to electrostatic separation. Enhanced separation between rutile and zircon was obtained when compared to untreated samples. Samples treated in a hydrogen atmosphere and cooled in nitrogen showed the best separation when passed through a high tension electrostatic separator using conditions of high sample temperature and high relative humidity.

Jan 1, 2005

By Gerhardt A. Bennewitz

The mechanism shown here (Fig. 1) may not be all that it appears to be. To many of you it may look like a hopper car, a thing of mobility, in which you would ship coal, ores, limestone, or other bulk materials. It is approximately 50 feet long, 12 feet high, and can be placed on tracks which are on approximate 14 foot centers. But far too often in the past, and all too often today, this mechanism has been made to serve as an immobile storage box, with its primary role -- the transportation of products, seemingly incidental to the storage function. Our engineering training teaches us to conserve resources, despite some of the popular and misconceived philosophies being advanced these days. Those of you who work for companies with traffic departments know that they are always striving to reduce the price which is paid to move your mine products. Today, let's consider and analyze the ways in which the cost of transporting your mine products might be reduced, based on particular reference to coal. Bear in mind that in this context, cost and price are not necessarily synonymous. Until a few years ago, most coal and other bulk materials handled by railroads moved under standard tariff rules. These rules, which still exist today, provided transportation vehicles (railroad cars) for extended periods at no added price to the shipper or receiver. "Normal" free time rules would permit a car to be held for a maximum of 48 hours without charge; however, in the case of coal, there is a rule which, subject to liberal rules as to the

Jan 1, 1972

By Dave D. Ferris

Today the coal industry is beginning to use some very fundamental economic evaluations to determine the most economical circuit to produce a specified saleable product. The fundamental economic methods used are standard return on investment and net present value calculations. By utilizing these economical evaluations, one can justify a larger capital expenditure and realize more return for an investment over the life of a coal property.

Jan 1, 1983

By Roger N. Miller

Talc mining in Vermont has in recent years undergone a progressive change in mining methods and in mining equipment. Underground mines have been phased out except in special circum- stances, and continuous mining machines (CMM?s) have replaced conventional drill/blast mining systems. Talc mining in Vermont began in the late 1800?s, and has continued without interruption to date. Beneficiation (flotation) has been applied since the early 1930?s, and has provided special products for toiletries and other markets. At the present time, there are two active companies that have evolved from the cumulative absorption of nearly ten smaller operations.

Jan 1, 1984

By C. J. Lewis

Considerable amounts of the world's known reserves of elemental sulfur are found near the surface in areas of volcanic activity both active and inactive. Because such deposits cannot in general-be mined by the well-known Frasch process, and because other methods of recovery have not proven to be economically competitive except in isolated instances, at present these reserves remain relatively undeveloped. However, projections of world sulfur demand indicate that new sources of marketable sulfur will be needed in future years 2/, 19/. For this reason, recovery of elemental sulfur from these near-surface deposits is of continuing interest. Solvent extraction as an approach to recovery of elemental sulfur from open pit-mined ores of these non-Frasch deposits has received considerable attention particularly at the research and development level 3 /, 7/, l l /, 16/, 21/,23/, 29/ This method has been and continues to be attractive because it presents the potential of high sulfur recovery and purity of product coupled with a relatively simple process flowsheet in which low energy requirements and reasonable operating costs are thought to be possible. However, the physical and chemical characteristics of the native-sulfur ores, of elemental sulfur, and of the known solvents, have presented difficulties in the development of solvent extraction processes. Up to the present time, viable processes have not been realized within the framework of sulfur marketing conditions.

Jan 1, 1970

By L. A. Puchkov

Problems of how to use artificial intelligence (AI) methods and expert systems (ES) to control complex industrial projects have lately become significant in practical terms. Mining ventilation systems undoubtedly belong to complex multi dimensional objects of control with stochastic nonstationary and nonlinear processes. Formal models based on automated ventilation control, do require awkward algorithmic solutions, moreover, a number of tasks become the operator's headache, and the quality of their solution depends on his experience and intuition. These tasks include: - identifying pre-accidental situations and determining their causes; - making well-grounded decisions with regard to changing ventilation regimes, forecast of mining operations taken account of; - controlling ventilation systems in emergency situations, e.g. when in accident, etc. It is in this context that we have for a number of years been investigating how to practically use AI methods for operative control in dynamic aero-and-gas mining processes, one of our research directions being devoted to working out a consulting programme for the ventilation system operator. Our researching and modeling problem was identification of aero-and-gas situation in different parts of ventilation network and its interpretation in order to determine possible causes for gas regime changing and unexpected consequences. We would single out the following stages in this task: I. Operative information procession coming to the data base from the sensors and analysis of hypothetical versions (using the associative rules base) with regard to factors which have caused significant parameter fluctuations (e.g. C%(t), H(t), Q(t) etc.)., 2. Selection of hypotheses in the knowledge base and forming conclusions in accordance with reliability scale. 3. Clarifying the obtained conclusions in dialogue with the operator. 4. Correcting the associative rules base.

Jan 1, 1992

By Charles A. Beasley, Vince Joyce, David E. Beasley, Orlando A. Gallegos, David A. Shuman, Mehmet H. Erten

COAL CHARACARISTICS AND PREPREPARATION REQUIREMENTS Preparation and Market Specifications The national ambient air quality standards (NAAQS) established by the Environmental Protection Agency in 1977 require that when coal is burned, the environmental degradation should be a minimum. For this reason, even coal containing low ash and sulfur must be used in compliance with the NAAQS. The most important pollutants resulting from the combustion of coal are ash, SO2, and NOx gases, and the particulate matter escaping with the combustion gases. The ash is the residue left after complete combustion of coal. It results from the inorganic mineral matter existing in the coal before it is burned. The SO2 results from the combustion of inorganic and organic sulfur associated with the coal. The inorganic sulfur may occur as pyrite, marcasite, or as sulfate sulfur of mostly iron and calcium. The authorities disagree in the definition of organic sulfur in the coal. However, according to ASTM Standard D2492-77,1 the organic sulfur is that sulfur occurring in the coal after subtracting the sum of pyrite and sulfatic sulfurs from the total sulfur in the coal. The NOx gases are produced from high temperature oxidation of nitrogen in the coal that is released into the atmosphere. The particulate matter may consist of fly ash and unburned coal. Selective Mining The cleaning of coal from included ash and sulfur-bearing materials should start at the working faces of surface or underground mines. This can be done by (1) mining only those seams which meet certain quality standards, (2) not mining sections of the seams which may cause deterioration in overall quality of the mined coal, and (3) using a mining method that allows selective mining of coal areas or horizons either underground or on the surface. Since these steps improve the coal quality before the coal reaches the preparation plant, they can be considered to constitute precleaning of coal. During the exploration and development stage of a mine, core and channel samples taken from the coal seam are used to determine (1) petrographic analysis and physical properties,2 (2) character of roof and floor of the seam, 3,4 (3) character and quality of impurities,5 (4) proximate and ultimate analysis, and (5) washability characteristics. However, all of these parameters are subject to considerable variation even within the same seam during the advance of the coal face. This creates a problem in meeting the market demand for coal quality if the coal is to be shipped directly from the mine. If the mining operation is large enough, special blending silos or mechanical blending systems may have to be used to provide uniform quality to the market. However, even if the coal is shipped from a coal preparation plant, prepreparation

Jan 1, 1991