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By J. Bowders

A case study describing the expansion of Marion County landfill is presented. The exapansion area is located on a deep mined area. Finite element analyses were used to predict the surface subsidence and associated tensile strains on the landfill liner of the expansion site. A synthetically reinforced liner system is recommended to minimize the impact of the subsurface movements on the integrity of the liner system.

Jan 1, 1986

By Qing-Wang Hao

In this paper, the authors attempt to develop engineering based approaches for estimating safety factors against pillar and floor failures and predicting likelihood of subsidence events over abandoned coal mines in Illinois. There are two critical problems involved in the analysis: determination of geotechnical properties, and consideration of time effect. The authors attempt to solve the problems by generating hypotheses, which are used to modify existing engineering models for estimating pillar and floor safety factors. The modified models are validated using data from two well established databases of subsidence events over active and abandoned mines in Illinois. The data analysis suggests that most of the trough type subsidence events in Illinois were caused by floor failures rather than pillar failures. The subsidence incubation period seems to be directly related to initial floor safety factors at the time of mining. This correlation can be used to predict the likelihood of subsidence and to assess subsidence risks within both spatial and temporal contexts where detailed mine maps are available.

Jan 1, 1986

By P. Somasundaran

Electrochemical properties of silicate minerals govern their behavior in processes such as flocculation and enhanced oil recovery that can occur at elevated temperatures. Knowledge of these properties as a function of temperature can be helpful in developing an under- standing of the role of these interfacial properties at non-ambient temperatures. Zeta potential of Sodium Kaolinite and quartz has been determined as a function of pH and temperature in this work. Both systems exhibited markedly different behavior at higher temperatures and also exhibited significant hysteresis. Results are examined in terms of possible dissolution of the minerals and surface reactions at different temperatures.

Jan 1, 1986

By R. B. Lantz

Low Froude Number (Fr) theory* predicts that stably-stratified fl& around a terrain obstacle will divide into a lower layer passing essentially horizontally around the obstacle and an upper layer passing essentially over the obstacle. The prediction was formulated by Sheppard (1956) and Drazin (1961) and confirmed experimentally in the towing tank model d experiments of Hunt et a1 (1978) and the atmospheric full scale experiments of the US EPA Complex Terrain Model Development Program (1982- 1985). The US EPA Complex Terrain Dispersion Model, currently under development, employs the layering principle with the flow in each layer calculated independently by potential flow (PF) theory after the layer thicknesses are established according to a simple function of Fr, i.e., Hc /H = 1 - Fr where Hc is the dividing streamline freight and E is the obstacle height. Use of PF theory in the CTDM is attractive because numerical solutions can be obtained simply and economically, as compared to lengthy Navier-Stokes (N-S) solutions, but realism is sacrificed in creating a surface of discontinuity between the tm layers and eliminating the effects of shear and gravity in each layer.

Jan 1, 1986

By E. D. Stephenson

As part of the British Steel Corporation?s development plan during the 1970?s, it was decided to concentrate its bulk steelmaking processes based on the BOS at 4 major Works with access to deepwater ore terminals, for the supply of high-grade imported ores. These 4 sites were at: - 1. Rarenscraig Works in Scotland where the ore terminal would be hilt at Hunterston on the west coast some 50 miles away. Bavenscraig was already an integrated Works but suffered from having to discharge ore 27 Glasgow tenxinus on the River Clyde, which could only accommodate vessels up to 25,000 tonnes. In the future, ore was to be unloaded at Runterston and shipped by a rail-link into Ravenscraig, The new ore terminal would have the potential to unload vessels up to 300,000 tonnes. - 2. Port Talbot Works in south Vales where the existing harbour was developed to discharge large ore carriers. This again was an existing Integrated Works and the benefits of the new harbour also applied to Llanwern Works which was another integrated Works some 50 dies to the east, which would now receive ore from Port Talbot.

Jan 1, 1980

By John Sasadi

The mining industry depends upon inexpensive water transportation. Today, large quantities of mined products are transported by ships over oceans, from continents to continents, over lakes and waterways to the ultimate users. Sometimes, the routes these Bulk Carriers travel cover only a few hundred miles, sometimes thousands of miles halfway around the world. Most of the products of the mining industries are relatively inexpensive. A significant portion of their cost to the ultimate users are in the cost of transportation and not in loading and unloading these commodities at the ports of origination or destination. So far, the industry has produced very efficient loading and un- loading installations, but has very little influence over marine transportation or the design of the vessels themselves. Very little was ever published dealing with integrated transportation systems properly correlating all phases of the operation; namely, loading, marine transportation and unloading bulk materials.

Jan 1, 1967

By Richard E. Gray

Virtually all structures show some signs of distress due to deterioration of the building components, to changed loads, or to changed support conditions. Changed support conditions result from ground movements. In mining regions many cases of structural distress are attributed to mining without considering alternative causes. This is particularly true of coal mining since it occurs under extensive areas. Coal mining is estimated to have already undermined more than eight million acres and may eventually undermine 40 million acres in the United States (HRB Singer, Inc., 1977). Other nonmetal and metal underground mines impact much smaller areas. Although it is sometimes difficult, even with careful study, to identify the actual cause of damage, persons responsible for underground coal mining should at least be aware of possible causes of building stress other than mine subsidence. This paper presents information on distress to structures and briefly reviews a number of causes of ground movements other than subsidence: Mass movements, dissolution, erosion, frost action, shrinking and swelling, yield into excavations and compressibility

Jan 1, 1986

By Byron C. Hardinge, Michael Sokaski, Paul F. Sands, W. Loring III Mc Morris, David J. Akers

INTRODUCTION In the early days of coarse-coal cleaning by the dense-medium process in Europe, loess was one of the materials used for medium solids. Newly developed cyclones were used to reclaim and thicken the loess suspension. On occasion, when the cyclone thickener at the Maurits mine in the Netherlands plugged, the overflow was found to be filled with clean coal free of impurity. From this observation stemmed the concept of the cyclone as a cleaning device. Development took place during World War II in the laboratory of the Dutch State Mines under the direction of M. G. Driessen. A 15-tph (13.6 t/h) pilot plant was in operation in the laboratory by 1945, when, in September, Driessen made the first public disclosure of the process in a paper presented to the Institute of Fuel in London.51 In April 1945, operation of this pilot plant was observed by H. F. Yancey, who was so impressed with the potential of the cyclone process that, on his return to the United States, a research program on the cyclone was immediately started by the US Bureau of Mines (USBM). This work led to an AIME paper in 1946 in which the first details of cyclone operation on American coals were made available.52 Commercial adoption of the cyclone proceeded in Europe, initially in the Netherlands, Germany, and France. In the United States, where coal is less costly and most of the coals are easy to clean and respond well to simpler cleaning processes, the first cyclone plant was not built until 1961.53 THEORY Before discussing the theory of a dense-medium cyclone, a brief description may be helpful to some readers who are not familiar with its basic operation. In a typical dense-medium cyclone, illustrated in Fig.7-51 a mixture of medium and raw coal enters tangentially near the top of the cylindrical section, thus forming a strong vortical flow. The refuse moves along the wall of the cyclone and is discharged through the underflow orifice. The washed coal moves toward the longitudinal axis of the cyclone and passes through the overflow orifice, or vortex finder, to the overflow chamber. Washed coal is discharged from this chamber, usually through a tangential outlet.

Jan 1, 1991

By Eberhard Werner

Existing reports on the effects of mine subsidence on water wells and springs appear to be inconsistent. Some report quick and complete recoveries to pre-mining conditions while others indicate long-term or permanent effects. It is clear that topographic and geological factors as well as precise position with regard to the mine are important in determining probable effects of subsidence on aquifers. Ridgetop aquifers which are well above regional base-level are much more susceptible to disturbance by mining activities than those located topographically lower. Effects seen are attributed largely to increased permeability, both horizontal and vertical. of the aquifer rocks. The deeper aquifers usually show short term losses or water-table declines. but the effects on the ridge-top aquifers persist for longer periods or may be permanent. Subsidence enhances permeability. so that infiltrating water moves much faster to lower levels. causing pond and stream losses and declining levels in wells as well as declining flows of springs of the higher aquifers, while increasing levels and flows of the lower aquifers. Additional effects are shifts of spring locations caused by minor tilts due to differential subsidence and redirection of shallow flows by changes of horizontal fracture permeability. These effects are seen as mining of a panel progresses beneath the site. and are often repeated when adjacent panel mining fronts pass the site. Analysis of water well level and spring flow records indicates that the effects are greatest at the edges of longwall panels in the tensional regime. These effects are amplified for locations close to topographically steep terrain and in close proximity to fracture traces mapped from medium-to small-scale aerial images.

Jan 1, 1986

By A. H. Baldo

Covers a very broad spectrum of problems and solutions. The problems are multitudinous and their solutions are sometimes simplistic, sometimes ingenious and sometimes within a very broad interpretation of the law. However, one thing is quite certain: the problems and their solutions will have a direct impact upon corporate and personal well being. First of all, why does one mine in a foreign land? Since the Bronze Age, when ancient man discovered the metallurgy of copper, tin and zinc, intrepid souls have been wandering afield searching for and exploiting those mineral deposits which would create wealth and security for his city-state or community.

Jan 1, 1981

By Klaus Grebe

Recent investigations by Mannesmann Research have shown that disintegration of sinter with widely varying quality levels is subject to a much more complex set of influences than was previously assumed. It was confirmed that disintegration at temperatures between 300 and 600 °C is triggered by the degradation of hematite. The specific tendency of hematite to disintegrate is, however, not constant: sinters containing the same amount of hematite can show widely differing disintegration tendencies depending upon structural homogeneity, porosity and gangue quantity. Especially sinters with heterogeneous structures transmit stress to the hematite phase and this favours disintegration. Another factor is the brittleness of the glassy silicate phase, which can be influenced even by small modifications of minor gangue constituents.

Jan 1, 1981

By William F. Jenks

The possibility that a hypothesis explains almost all observed facts may be satisfying. Yet the almost gives a distinct sense of uncertainty. Moreover, overlooking the almost, reliance on the favored hypothesis may close our eyes to the discovery of new information and, in the field of mineral exploration, to the possibilities of finding new and hidden ores. A case in point is that of mines such as the Elizabeth and Ely, along the copper belt in eastern Vermont, principally in Orange County. The geology of the Strafford Quadrangle, where the Elizabeth Mine is located, has been described by Doll (1944). Two informative papers (McKinstry and Mikkola, 1954, Howard, 1959) present much valuable information about the geology of the Elizabeth Mine. Both reach the conclusion that the ores were emplaced after the peak of metamorphism, through the agency of metal-bearing hydrothermal solutions. Both, therefore, conclude that the source of the ores was somewhere below the outcrop area, presumably in some hidden intrusive mass. Neither yields a satisfactory guide for further exploration. Howard (1959) cites geophysical observations which show that there is a mass with a density similar to that of granite under the Strafford dome, adjacent to the Elizabeth Mine on the West. Yet examination of gneissic granite in the Chester dome, 25 miles to the South gives no suggestion of a young, near-surface intrusive capable of carrying or mobilizing large quantities of sulfur and metals. The Acadian intrusives in New Hampshire and in the Barre district

Jan 1, 1968

By O. Tsuge, G. Hoffman

ITmk3®(Iron Technology Mark III) is an innovative new ironmaking technology whereby high quality iron nuggets are produced directly from iron ore fines and coal in a rotary hearthfurnace1). The reaction mechanism has been investigated in detail through fundamental laboratory research2)3), and the ITmk3 process has progressed from the laboratory to commercialization by the success of the pilot plant tests initiated at Midrex’ Technical Center and at the Kakogawa Bench Plant (KBP) located at Kobe Steel Ltd. Kakogawa Steel Works4)5). Pilot operations have demonstrated rapid production of the iron nuggets with complete metal/slag separation at a relatively low operating temperature. The Kakogawa Bench Plant (KBP) in Japan has logged 21 days continuous operation during which high quality iron nuggets were produced directly from fine ore and coal. The operation technology and the engineering data obtained from these pilot tests were instrumental for the scale-up of the ITmk3 process for the Mesabi Nugget Corp. pilot demonstration plant, which is located at Cleveland Cliffs Inc. Northshore Mining iron ore pellet plant in Silver Bay, MN. The ITmk3 process is an ideally suited technology for siting at the iron ore mine, as it allows the economical production of a value-added merchant iron product.

Jan 1, 2003

By E. J. Karges

The use of pulverized coal for generating power and performing industrial processes has made an important contribution to our industrial economy during the past half century. Actually, the burning of coal in powdered form is a subject that has held the attention of engineers for a century or longer. Its widespread use, however, is comparatively recent, As early as 1866 patents were granted to Messrs. Whelpley and Storer for a method of feeding pulverized coal into a furnace as an auxiliary to the grate fuel. In the many tests made during the subsequent years with various kinds of apparatus, the experimenters were handicapped in not getting the coal fine enough to obtain complete combustion and to prevent excessive formation of slag.

Jan 1, 1965

By James L. Coburn

Leaching is defined as a form of extraction in which a valuable constituent is removed from a solid body by mass transfer to a solution which, for the purpose of this discussion, is considered to be an aqueous medium. Historically, leaching has been applied to the recovery and purification of many elements. This paper, however, is directed toward the recovery of copper, uranium, vanadium, and precious metals included in the following systems: 1. The leaching of copper minerals, sulfides and oxides, by acid or by ammoniacal leach solutions with or without an oxidant. 2. The leaching of gold and silver, either native metals or as minerals by an oxygen-containing alkaline cyanide solution. 3. The solubilization of certain uranium and vanadium minerals by oxygen or oxidant-bearing lixiviants. Many other systems of this general type exist, but from a production standpoint, these three systems account for most of the major values recovered by leaching.

Jan 1, 1975

By C. D. Broadbent

Open pit blasting can be a low cost routine or a high cost bottleneck depending on geology, environment and the operator's ability to master site conditions. Because blasting is a repetitive operation, there should be ample opportunity to optimize the process; but ordinarily this optimization is rarely achieved and then only if conditions remain consistent and predictable. Often, however, and particularly with porphyry coppers, hidden differences in rock characteristics nullify the operator's best efforts. At a porphyry copper deposit being mined by Kennecott Copper Corporation, there are all of the following rock types: oxidized and fresh porphyry, altered and silicified limestone, explosion breccia, rhyolite, sandstone, shale and several others. The units can cover large areas or be limited to a few tens of feet in maximum dimension. They are rarely visible on the bench surface and often do not show up in the bench slope. Even though the blastability of these rocks varies substantially, a generally-uniform blasting pattern was formerly used with disappointing results. Secondary blasting was often required and high bottoms occurred frequently; overblasting wasted drilling time, and explosives caused excessive throw. Several possible methods for improving the blast design were considered and a geophysical method was chosen for testing. There had been reports in the journals that seismic methods were being used in Europe as aids for blasting design. A literature search turned up work by Haxby 1/ on use of a refraction seismograph for measuring pit bench rock strength. Using his work as a springboard, equipment was purchased and a program was planned and carried out for developing, evaluating and implementing the seismic method for routine mine use. Following are discussions of the development program and results.

Jan 1, 1974

By J. Paraszczak

Metal mining at great depths presents a number of serious challenges for mine operators. Among them is the high demand for fresh air required to cool down mine openings, evacuate noxious gases and contaminants and provide sufficient amounts of oxygen for miners. At the same time, modern mechanized mines extensively use diesel-powered load-haul-dump (LHD) machines, trucks and other mobile equipment. These vehicles not only emit exhaust gases and diesel particulate matter (DPM), but constitute an additional source of heat. As mine regulations get steadily more stringent with regard to air quality, the use of diesel engines has an additional adverse impact on ventilation costs. In this context, the present paper examines possible alternatives for diesel power trains, both those commercially available and those in development. They are reviewed with regard to their principles, required infrastructure, stage of technology development and progress. The questions of their flexibility, practicality and economic viability are also addressed. Finally, their possible benefits and potential for implementation in the conditions of deep metal mines are discussed. The paper concludes with short- to medium-term predictions concerning promising drive alternatives for vehicles destined to operate in deep metal mines.

Jan 1, 2009

By ERIK CHARRIER, ADITYA JUGANDA, Jürgen Brune, Patrick Maier, Gregory E. Bogin Jr

Confined explosions are a major risk in underground coal mine operations. Depending on confinement, ignition location and obstacles in the flame path, methane explosions can transition to detonations. As a result, the severity of mine explosions ranges from minor damage to loss of lives and permanent mine closure. Experimental results have shown that the inclusion of obstacles can significantly increase the flame propagation velocity by inducing turbulence. This research focuses on explosion experiments in a 71 cm diameter, 30.5 m long reactor that includes rock piles as obstacles along with developing the corresponding CFD model that captures the observed flame behavior and interaction with the obstacles. The rock rubble increases the flame front propagation velocity by 500% compared to the maximum velocity observed in the empty reactor experiments. The 2D and 3D CFD models predict the experimental flame front propagation velocity, whereas the 3D model shows a more explicit conformity than the 2D model. Although the computational time to complete the simulation is much less for the 2D model than for the 3D model, the 2D model is not sufficient to simulate cases with rock rubble since it cannot capture the propagation of the flame through the small voids between the rocks with the same effective blockage ratio as the 3D model. The validated CFD model can be scaled up to simulate methane explosions in full scale mine and industrial settings.

Nov 20, 2023

By A. W. Fletcher

A nickel-copper sulphide concentrate was treated in a pilot plant at Warren Spring Laboratory during 1961, by a hydrometallurgical roast-leach- solvent extraction process devised to cleanly separate the metal values, and produce acid sulphate liquors containing the metals. It is shown that 86 percent of the nickel and 95 percent of the copper could be leached from the calcine, after a sulphatizing roast on finely ground flotation concentrate. Iron was removed from the leach liquor by limestone neutralization with a small loss of values. Copper and nickel were separated by solvent extraction with naphthenic acid in kerosene after partial neutralization of the iron-free liquors with ammonium hydroxide. Hydrogen sulphide and chlorine were used to remove zinc (and residual copper) and cobalt impurities respectively. The recovery of pure copper and pure nickel, by electrowinning, from the acidic solvent extract strip liquors finally produced, appears technically feasible.

Jan 1, 1964

By Joseph M. Chelini

Today, the two major operating costs of rubber tired off-road equipment are diesel fuel and tires. Mine Management has minimal control over the ever accelerating diesel fuel costs. However, they can exercise control over abnormal tire costs. Fortunately, with available technology and cost analysis methods, experience shows us the outlook for controlling tire costs is encouraging. Most earthmoving operations using off-road, rubber tired haulage and support equipment have abnormally high total tire costs. These costs, utilizing Tire Information Management, have been reduced more than 30%; 20% can often be guaranteed. Management Apathy on the subject of tires in a complex mining operation perhaps can be understood, but management apathy applied to an abnormally high operating cost, of which tires are, begs for a solution.' Tires have been professionally neglected for many years in most mine operations. This is exemplified in the January, 1982 issue of Mining Engineering by Charlie Son in his article Reducing Earthmoving Tire Costs. He compared the efforts to improve diesel engine costs to the same efforts given to earthmover tires.

Jan 1, 1983