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By Peter T. Luckie

Up until the past couple of years, thermal coal dryers were only used to dry midwest and eastern United States bituminous coals. These dryers were primarily installed at coal preparation plants to freeze proof the coal and lower the transportation costs per BTU. Today thermal coal dryers are being specified to dry western sub-bituminous and lignite coals for these and other reasons brought about by the intense interest in coal gasification and liquefaction. One reason for drying western coals ahead of a coal gasification plant is the elimination of surface moisture which would prevent efficient sizing of the coal, since feed material size consist is very important in most commercial coal gasification processes. Thermal dryers are being proposed for liquefaction processes because of the need for a feed material containing approximately 4% or less total moisture Future coal gasification processes may also need to reduce feed material moisture content.

Jan 1, 1975

By Robert J. Neubauer

I was asked here today to discuss the first long-term freight rate contract ever signed by a U.S. railroad and shipper. That was ICG's contract with the hoosier energy company to haul coal from southern Illinois to an Indiana power plant. I?ll also talk about why you can expect to see more such contracts in the future But first, let me tell you a little bit about the Illinois central gulf railroad and why coal contracts are so important to us. ICG is a principal mid-American freight carrier. We are one of the ten largest railroads in the united states and one of the ten largest coal-hauling railroads. ICG links the industrial great lakes region with the warm weather ports of the gulf coast. Some of the major points on our route map are Chicago; Indianapolis; Omaha; Kansas City; Memphis; St. Louis; and, of course, baton rouge and new Orleans.

Jan 1, 1981

By Dean E. Albon

In the late 1940's and early 50's in southern Illinois, the usual open pit blasting in the coal field consisted of one or two rows of churn drilled vertical holes being shot with instant electric blasting caps. The entire shot detonated at one rime. In southern Indiana and Ohio most mines were drilling horizontal holes and they too were primed with instant EB caps. During the ten years from 1355 through 1965 many changes occurred in drilling and blasting methods. The churn drill in southern Illinois and the horizontal drill in Indiana and Ohio were replaced by the rotary vertical drill. The ammonia dynamites and liquid oxygen explosives were replaced by ANFO. The elctric blasting cap in the hole was replaced by a detonating cord down line and detonating cord trunk lines made the connections between holes and rows of holes. Host open pit mining was in areas far enough from town that the noise and vibration from blasting was, if not ignored, at least tolerated. During the 1960's open pit mining expanded to account for nearly 50% of the coal produced. Mines came closer to town and towns expanded along the highways with suburban homes and mobile homes. The mines began receiving complaints about the noise and vibrations from blasting operations.

Jan 1, 1976

By G. T. Adel

During the past decade, researchers at Virginia Polytechnic Institute and State University have worked to develop a novel flotation process for treating very fine particles. This process, which is now commonly known as [microbubble column flotation] (MCF), has been shown to be very effective in a number of applications related to fine coal processing. These applications include the retrofit of existing preparation plant circuits and the recovery of additional coal fines from refuse streams. In addition, work conducted under the sponsorship of the United States Department of Energy indicates that the MCF process is capable of producing superclean and ultraclean coals from many eastern U.S. coals. This paper describes some of the basic problems associated with fine particle flotation and the design and operational features of the MCF process used to minimize these problems. Also presented are the results of ongoing pilot- and field-testing programs.

Jan 1, 1989

By David J. Kruse

Although it may be perfectly acceptable to neglect the belt's elastic behavior for many conveyor designs, this can lead to disastrous consequences for others. So how can a designer know in advance if a dynamic analysis is required? Unfortunately, in many cases it is impossible to foresee or predict dynamic problems prior to performing the actual analysis. However, a basic understanding of the principles of conveyor dynamics, as well as knowledge regarding common problem areas, can significantly help the designer make more educated decisions during the initial design stage. This paper will demonstrate how static calculations alone can incorrectly represent the true behavior of the conveyor system. It will also discuss the importance of correctly sizing and locating the take-up system to provide the most economical conveyor design. The use of capstans will also be discussed followed by two examples demonstrating their proper operation.

Jan 1, 2002

By E. M. Frizzell

Decisions affecting ground control design require detailed knowledge of roof rock geology. This is especially true when weak roof materials and anomalies create hazardous conditions and. if not properly supported, result in roof falls. The U.S. Bureau of Mines has developed a system to evaluate geological conditions by using a roof drill that will provide an estimate of the compressive strength of the roof rock in real time. Through the use of sensors and a microcomputer on the roof drill critical drilling parameters can be interpreted and analyzed almost instantaneously, making it possible to inform an operator of hazardous roof conditions such as voids and changes in strata during the drilling process. Geotechnical data can be downloaded to a portable semiconductor memory device, which is brought to the surface so that data can be directly accessed with a personal computer for further analysis. Results from field tests are presented.

Jan 1, 1992

By S. A. Bortz

IIT Research Institute has initiated several multi-sponsored research programs. In this paper the methods for developing four of these programs are discussed. In general, a broad area of investigation must be proposed to interest a spectrum of different industries. The work must not touch upon proprietary data and will probably involve a number of scientific disciplines. Thus, the problem to be solved will attract sponsors who need to know more about the area under study but do not wish, as a single company, to commit the resources required to obtain the necessary know-how for their needs. The paper draws on the background of four IITRI multi-sponsored projects: Size Reduction, a study of grinding of material to reduce their particle size; Melt-Formed Ceramics Research, a method of producing dense, polycrystalline ceramics using glass forming methods; Binders in Ceramic Processing, which addresses the problems associated with the use of organic aids for ceramic processing; and a Study in Air Pollution Technology, a program to review and assess pollution control equipment for current and future applications.

Jan 1, 1984

By James F. Lemons

The potential production of cobalt from nickel sulfide deposits in Canada, from nickel laterite deposits in the Pacific Islands, and from the copper deposits of Zaire and Zambia will be a function of the cost of recovery of the primary nickel and copper products. This cost of production varies significantly for these deposits and is related to the differences in the cost of labor, energy, and supplies, to production technology, and to the grade and recovery of nickel, copper, and cobalt. This Bureau of Mines paper investigates these cost and technology differences as they relate to the cost competitiveness of the deposits in Canada, Zambia, Zaire, and the Pacific Islands.

Jan 1, 1984

By M. E. Lewellyn

A lower moisture content for a clean coal product means increased Btu content, or increased yields at the same Btu content, and lower operating costs. The conventional surfactant-based dewatering aids effeciently lower the moisture content but often the presence of residual surfactant in the filtrate and recycle water causes problems downstream. ACCOAL-DRI 1000, a surfactant-based dewatering aid, was developed to solve this problem by minimizing the downstream effects while efficiently lowering the moisture content. The theory of the use of surfactants in filtration will be discussed as well as the development and field evaluation of this new product.

Jan 1, 1988

By Paul Eimon

In the world of minerals exploration, computer-oriented data storage and retrieval methods are being talked about, studied and researched. The goal is to facilitate the recording, collating, indexing, recovery, and analysis of mineral deposit-prospect data. A survey has been made of the various report forms, suggested outlines, and computer coding forms that are currently used in mineral exploration to index and/or describe mineral deposits and prospects. These forms have a number of common characteristics: location, commodities, type of deposit, host rock, etc. Such basic mineral deposit-prospect "data units" are part of most exploration programs. "Data units" may be comprehensive bound published descriptions of mines or mining districts or 3x5 file cards or elaborate computer coding forms being developed in Canada. Initial attempts to develop computer-oriented information systems have run into the same roadblock: the lack of a body of organized, processible data describing the basic qualities of mineral deposits and prospects. To solve this problem, international committees are considering coding forms, world-wide semantics, and rules or standards for data collection and description. It appears that mistrust and lack of understanding of the computer; fear of loss of proprietary information; and disagreements over terminology are distorting the picture of what has to be done if the mining industry is to grow into more meaningful information systems for mineral exploration.

Jan 1, 1969

By Gregg J. Hodges

The Stillwater Mining Co. is a partnership of The Pittsburg & Midway Coal Mining Co. and Manville Corp. The Stillwater Mine, located near Nye, MT, is the Western Hemisphere’s only primary platinum-palladium deposit. The mine began production of flotation concentrates in March 1987. In the fall of 1987, an integrated pilot plant testing campaign of electric furnace smelting and oxygen-blown converting confirmed the feasibility of further upgrading to semi-refined matte, or “white metal.” In the summer of 1990, the production smelter was brought on line. The record of the discovery and development of the Stillwater deposit, mine and concentrator has been summarized in several articles (White, 1987; Kennedy, 1987; and Hodges and Clifford, 1988). Similarly, the pilot campaign to test the feasibility of treating the flotation concentrates in an integrated smelting plant has been described (Hodges and Clifford, 1988; Matousek, et al., 1989; and Matousek and Whellock, 1990).

Jan 1, 1991

By S. Möllerherm

"Since the adoption of the Rio-Declaration in 1992 the concept of sustainable development is raising more and more awareness in public perception. The World Commission on Economic Development WCED has defined sustainable development as the concept that "meets the needs of the present without compromising the ability of the future generations to meet their own needs". The concept requires the integration of economic, environmental and social considerations into all decision making, fostering intra-generational equity through the alleviation of poverty by concentrating the benefits of development in lesser developed areas; and considering the needs of future generations to ensure that inter-generation equity exists. This paper is devoted to give a review of the current status quo of the discussion. It describes the achievements of the mineral industries on their progress towards sustainable development since the Milos Conference (SDIMI 2003), but also discusses future challenges and obstacles."

Jan 1, 2005

By Dave Willis

Two hundred and thirty million tons of coal! That is what the Burlington Northern (BN) railroad anticipates that it and the Chicago North Western railroad (CNW) will haul out of the southern Powder River Basin l (see map on page 966) in 1994. Put that 209 Mt (230 million st) into railroad perspective. Current average train size is 113 cars. With each car transporting 94 t (103.5 st) of coal, each train averages 10.6 kt (11,700 st) of coal. Simple division shows that 209 Mt (230 million st) of coal equals 19,658 trains a year. So BN and the CNW must move 54 loads a day out of the Basin. Every load, of course, has an empty side of its cycle. This means that 54 loads a day translates into 108 total trains a day, or 39,420 trains a year through the southern PRB.

Jan 1, 1994

By D. Marinakis

Gas hydrates (GH) are crystalline compounds consisting of a water molecule lattice, in the cages of which suitably sized molecules, such as methane or other light hydrocarbons, are confined. Although this solid phase looks similar to common ice, it contains substantial amounts of natural gas. The necessary conditions for natural gas hydrate formation exist in some deep-sea marine environments and in permafrost regions. Despite the extensive research, which has been conducted in the fields of exploration and exploitation of natural gas hydrate deposits over the last decades, there is still great uncertainty over the estimated amount of hydrates that these reserves bear. The present work examines some key features of sediments which affect their capacity to host gas hydrates. The hydrate content of a natural hydrate formation is correlated qualitatively with factors such as temperature, effective porosity, mineralogical composition, bio-surfactants, pore pressure and compaction pressure.

Jan 1, 2006

By M. H. Foroughi

This paper discusses the effects of seam inclination and lateral stresses on the stress distribution in pillars in inclined coal seams. The average pillar stress is a function of the overburden weight, the mine depth, the effective extraction ratio and the angle of seam inclination. Normal and shear stresses in the pillar are computed by numerical modeling. In medium dipping seams, leaving a pillar with its axis normal to the stratification causes a shearing stress concentration in the top and bottom corners of the pillar. This results in the pillar possibly becoming less stable in comparison to pillars in horizontal coal seams. Therefore, to reduce the stresses, it may be necessary to leave the pillar at an angle of b deviated from the normal axis to stratification. A mathematically approximate formula for determining b is proposed, and the results are confirmed by numerical modeling.

Jan 1, 1998

By William Mayrsohn

IMTRODUCTION The marketing aspects of a new precious metals property is often not considered until the mine actually begins production. At this point in time it is often too late or too expensive to change the mine's final product and not enough time to do an effective marketing program. MINE PRODUCT The rule for determining the mine's final product: The higher the gold and silver content, the greater return of metal at the lowest post-mining cost. . Dore Bullion: Most advantageous Advantages: - Highest return of metal. - Lowest refining cost per ounce of gold and silver. - Very compact and easy to ship in small quantities. - Easy to assay. - Assays between mine and refiner are comparable. - Melt losses are very small at the refiner. - Outturn of gold and silver 20-30 days for quick cash flow. - Gold/silver refiners can return or purchase metal soon after arrival at a nominal financing cost.

Jan 1, 1987

By Robert C. White, Kurt W. Keskimaki

The Henderson Mine is a large underground panel cave molybdenum mine located near Empire, Colorado. Diesel equipment is employed for all development work, as well as production ore handling. Due to fluctuating demand for molybdenum, production rates have varied from 16,000 to 32,000 metric tons per day (18,000 to 36,000 short tons per day) over the last four years. In order to obtain the maximum air flow for minimum power cost the Henderson mine has completed the following modifications to the ventilation system: removal of large intake fans, elimination of underground booster fans, shutdown of tunnel exhaust fans, completion of the number 5 exhaust ventilation shaft, and use of partially debladed main exhaust fans. These changes have reduced the annual cost of mine ventilation at the Henderson Mine by over 80 per cent, a very critical cost savings in today's competitive molybdenum marketplace.

Jan 1, 1989

By David M. Miller, Pramod C. Thakur, Larry D. Taylor

The most common technique used to suppress respirable coal dust in air is that of spraying with fine water particles. The water droplets are typically much larger than respirable dust particles and they collect dust particles mainly by interception. Dust collection efficiencies can be improved by reducing the droplet size and in- creasing the droplet velocity. This is typically done by reducing the surface tension of water and increasing the water pressure. Dust collection efficiency can be further improved by in- creasing the electrical attraction between the water and dust particles through electrostatic charging. A technique developed by Conoco accomplishes both surface tension reduction and electrostatic charging by discharging weak solutions of surfactants in water at high pressures, 13.8 to 27.6 MPa (2000 to 4000 psi) in an intrinsically safe manner. The paper de- scribes the process and presents related dust suppression data.

Jan 1, 1986

By D. G. Millette, A. J. S. (Sam) Spearing

The design of a cost effective backfill system involves many aspects and various inputs from different engineering disciplines. Backfilling is a very significant mining cost and efforts need to be made in the design stage to maximise efficiency and flexibility whilst minimising costs. The aspects that need to be considered include the following: Required fill performance underground Peak and average fill tonnage requirements Backfill scheduling in the mining cycle Material selection, testing and preliminary costing Plant design and storage needs Infrastructure requirements Implications on surface waste/tailings disposal and costs Total backfill costs In order to produce a cost effective and efficient backfill operation, a multi-disciplinary project team is required that should include the following skills and functions: Mine Planning Rock Engineering Metallurgy Mechanical Engineering Environmental Health and Safety Tailings Disposal/Waste Management This paper discusses the above and indicates important aspects that should be considered.

Jan 1, 2001

By A. Pratt, G. Deschênes

This paper quantifies the detrimental effects of pyrite and stibnite on gold leaching kinetics. Means to reduce the effect of these minerals by addition of lead nitrate and oxygen are presented. A significant retarding effect was observed when the pyrite concentration was 20%. A pretreatment with lead nitrate reduced the extent of gold surface coating by Ag, Fe and S. Stibnite, at a concentration as low as 20 ppm, significantly affected the gold leaching kinetics through forming a passivating film of Sb(V) oxide possibly Sb2O5. The most practical way to alleviate the effect of stibnite is to leach the materials at a moderate pH with addition of lead nitrate. A low temperature reduced the efficiency of lead nitrate to counteract the effect of stibnite. The increase of dissolved oxygen is not favourable to alleviate the coating of stibnite on gold.

Jan 1, 2004