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By B. K. Parekh, W. M. Goldberger

Sludge obtained during the production of magnesium (Mg) from molten MgCl2 by electrolysis contains entrapped magnesium particles. The sludge containing the magnesium particles is a friable, continuous matrix of frozen salts that may also contain some oxides and impurities. Due to the high reactivity of magnesium metal with water, a dry process was developed to recover magnesium metal from the sludge. The process utilizes mineral-processing unit operations. The steps include selective comminution, screening, attritioning and tabling. Recovery of the high-grade (>90%) metal was in the 70% range. The novel process was also successfully applied to a magnesium-alloy for the recovery of metal from the sludges.

Jan 1, 1997

By W. K. O’Connor, J. C. White, P. C. Turner

The US Bureau of Mines is investigating the cobalt and manganese resource of the West-Central Arkansas district through field investigations, mineralogical characterization, beneficiation and hydrometallurgical tests. Located within the Ouachita Mountains, these structurally-controlled deposits occur along the axes of anticlines that form the mountain ridges. Brecciated novaculite is cemented with a mixture of manganese oxides, primarily cryptomelane and psilomelane. Cobalt is concentrated within lithiophorite, a particular Mnoxide phase. Chemical analyses of head samples reported up to 25% Mn and 0.17% Co. Magnetic separation yielded products containing up to 41 % Mn and 0.22% Co at recoveries of 95% and 93%, respectively.

Jan 1, 1993

By D. G. Foot, J. D. McKay, R. A. Ynchausti

The increasing popularity of column flotation as an efficient and profitable mineral beneficiation technique has resulted in the need to perform a study of basic column operating parameters in order to understand mineral behavior in a column. Variation of column rougher flotation parameters on the Nevada Fish Creek fluorite and Utah Collins manganese ores enabled characterization of four beneficiation zones within a column flotation cell. Although specific mineral behavior in each zone was peculiar to the mineral system involved, particle retention time predominantly affected both manganese and fluorite recoveries in the collection zones of the column while enhancing mineral grades in the cleaning zones. Column parameters such as column length, feed injection location, and tailings recirculation velocity were inherently linked to particle retention time and retention time distribution, both of which affected mineral recovery. Froth depth had a discernible effect on fluorite concentrate grades; as froth depth increased, fluorite grades increased. Wash water additions affected both fluorite and manganese recoveries and fluorite grade. Axial mixing drastically reduced fluorite and manganese recoveries due to short circuiting of some of the feed slurry in the column.

Jan 1, 1988

By C. R. Fahnestock

One of the major problems for us in the earthmoving industry is the analysis of materials under the ground surface. Countless engineering and construction jobs would be simplified if there were an inexpensive and fast way to obtain information on problems such as: Depth and solidith of bedrock? Nature of the materials between bedrock and the surface? Adequate foundation for bridges and drainage structures? Location of supplies of materials to be used in construction? Investigation of tunnel sites? Characteristics of swampy areas and investigation of existing and potential slide areas? These questions are of paramount interest to highway contractors as they bid jobs and plan, equipment spreads to handle them at optimum efficiency. Such information also is invaluable to engineers in the design and construction of bridges, buildings, railroads, canals, and tunnels.

Jan 1, 1961

By Joseph T. Duncan, Syd Peng, Larry G. Stolarczyk

The mining business has numerous risks: equipment availability, labor disruptions, foreign exchange rate, etc., but one of the more important risks is assessing the geology. Improving the “intelligence” of geology can and will have significant positive effect on reducing mining risk and thus enhancing operational and financial performance. The use of the advanced Radio Imaging Method (RIM-IV) on coal seams and ore bodies can create useful two-dimensional (2-D) and three-dimensional (3-D) high-resolution images that provide mining engineers with additional intelligence to better plan and improve operations. Improved operational performance will reduce costs and enable mining companies to meet market and financial commitments. For the past decade the underground coal mining industry has been moving toward “super panels” in long-wall mining, and “super sections” for room-and-pillar mining. These mining conventions employ wider faces, longer gate roads, greater room-and-pillar density, and an increased scale in the amount and complexity of mining equipment. An obvious economy of scale exists: amortization of setup investments over greater volume of coal enables mine management to reduce fixed cost per ton. Restricted by equipment considerations, face widths have currently reached about 1,100 ft. Wider longwall panels are planned, with 1,400-ft widths, but this requires an incremental step in hardware that the original equipment manufacturers will soon bring to market. However, longwall panel length has not yet reached its limits, with some panels planned up to 25,000 ft. While longwall panel length is generally dictated by reserve size and extent, practical restrictions in mine planning also include seam thickness, ventilation requirements, or restrictions involving methane drainage. Super panels have certainly enabled the industry to keep pushing the limits of productivity improvement. However, important considerations in mine planning, now and especially in the future, will be driven in large part by geological factors. While larger developments improve productivity and capture economies of scale, the fact that super panels can contain at least four times the area or coal volume means that the probability of encountering serious anomalies is at least four times greater than with the “conventional” panels. Given the increased probability of encountering anomalies, improved assessment of geology is important for super panels and super sections. Proper due diligence requires a thorough and competent evaluation of a mining property and its ore reserve. Using improved geostatistical techniques is most important, and improving the base data for the analysis is equally important. The old cliché “garbage in, garbage out” certainly applies. Also, the quality of coal reserves is (or has been) declining, so, in the future, mining will be in deeper and most likely thinner seams—and these seams appear to contain greater anomalies that threaten efficient operations. To counter the impact of reserve deterioration, the industry is moving toward greater use of geophysical tools and services. Fortunately, tools such as the Radio Imaging Method™ (RIM-IV) system have been improved and can provide the industry with enhanced 2-D and 3-D images of coal seams and ore bodies. To identify and profile the best areas of a coal reserve, geologists, engineers, and mine managers need greater intelligence in the form of RIM-IV tomographic maps of longwall panels and room-and-pillar sections. These images have enhanced the understanding of in-seam features, which in turn has improved operational plans and performance.

Jan 1, 2005

By E. William Rossi, Audrey F. Glowacki, Richard L. Unger

The U.S. Bureau of Mines has developed a graphics-based computer model to assess operator visibility for continuous miners, shuttle cars, and scoops. Using digitized drawings of the machine, the program can analyze visibility for both 5th percentile female and 95th percentile male operators. This model was used to predict 95th percentile male operator visibility for two shuttle car designs. These results were then compared to those obtained from a manual assessment of visibility using the actual shuttle cars. The methods showed good correlation except for several cases which were attributed to imprecise digitization of the machines.

Jan 1, 1992

By Tsuneyoshi Funazaki, Takayoshi Nakamura, Keizo Miki, Takashi Imaishi

The underground portion (about 10 km) of Tokyo Wan Aqua-Line consists of eight shield tunnels connected with Kawasaki Man-Made Island in between, at four underground locations. The connection work had to fulfill strict precision and safety requirements in the ground about 60 m below soft seabed, but was completed successfully in May 1997. This report describes the connection work in detail, featuring the method of investigating shield machines’ relative positions, ground freezing method and connection mechanism and procedures. It also mentions the present state of Tokyo Wan Aqua-Line that was put in service on December 18, 1997.

Jan 1, 1999

By D. C. Wilder

Deformations during heating and cooling of three drifts in granitic rock were influenced by the presence of faults and shear zones. Thermal deformations were significantly larger in sheared and faulted zones than where the rock was jointed. but neither sheared nor faulted. Furthermore. thermal deformations in faulted or sheared rock were not significantly recovered during subsequent cooling thus a permament deformation remained. This inelastic response is in contrast with elastic behavior identified in unfaulted and unsheared rock segments. A companion paper (Butkovich and Patrick, 1986a) indicates that deformations in un- sheared or unfaulted rock were effectively modeled as an elastic response. We conclude that permanent deformations occurred in fractures with crushed minerals and fracture filling or gouge materials. Potential mechanisms for this permanent deformation are asperity re-adjustments during thermal deformations. micro-shearing, asperity crushing and crushing of the secondary fracture filling minerals. Additionally, modulus differences in sheared or faulted rock as compared to more intact rock would result in greater deformations in response to the same thermal loads.

Jan 1, 1986

By Adrian Smith, Debra W. Struhsacker

There is now overwhelming evidence that, despite concerns to the contrary, natural degradation of cyanide and cyanide attenuation by hydrogeochemical processes are capable of minimizing or eliminating potential water qua1ity impacts from heap leach systems. A1 though there was some recognition of these data by the regulatory authorities, for example the initial USEPA modification of cyanide standards to an advisory level, many states have codified standards inappropriate to the clearly site specific nature of heap leach operations. As an overview to this problem, this paper will integrate the theoretical chemical data on cyanide with the observed geochemical behavior of cyanide in the decommissioned heap leach environment. The cyanide species that are likely to exist within an abandoned heap leach system will be identified, and the relative toxicity and potential environment effect of these cyanide species will be discussed. These data will then be used to evaluate cyanide detoxification regulations for decommissioned heap leach projects in 14 states.

Jan 1, 1987

By George J. Allen, Laura A. Allen

Introduction This section of the text presents a general review of the different types of concentrate marketing contracts. Too often the marketing strategy is ignored in the design phase of the project and the producer is left to the mercy of the buyer. Many items such as concentrate grade, impurity levels and moisture content of the concentrate my enhance, or severely restrict the producers ability to make a profit it. Close attention should be paid to the design of the concentrator which can improve the quality of the concentrates, thus the ability to increase the rider of potential buyers can be enhanced. Difficult at best, is the position of the miner who only has one outlet available for its production. Obviously, the trade offs must be evaluated. For example, concentrate grade vs recovery and grind/filtering capacity vs moisture of the concentrate all must be weighted against freight cost to a potential buyer. In addition, the above considerations must be weighed against the capital cost to the miner. This chapter is intended to highlight important articles that are included in short and long term agreements and to give a new miner/producer some insight into hat my or my not add value to the product. Unless the miner sells the product directly to a consumer such as a gold, or silver producer, or to a large enough operation that has a totally intergrated system to make a finished product, most miners are forced to sell to buyers who ultimately will refine and market the product. Types of Contract Agreements There are many types of contract agreements just as there are colors in the rainbow, however, most contracts fall into three basic categories. (1) Smelter Schedules: Designed for the small producer, the odd lot of concentrate, smelter flux and precious metal ore. Albeit custom smelters are becoming fever by the day, because of pollution control requirements and financial difficulties, most remaining custom smelters have a smelter schedule. A smelter schedule is a posted list of charges and conditions that the smelter will buy material from a seller. Smelter schedules exist for copper, lead, zinc, silver and gold (Handbook for Small Mining Enterprises, Montana Bureau of Mines). (2) Short Term Custom Contracts: Large mine producers frequently use Short Term Contracts where the seller has the buyer frame a contract that is tailored to the sellers’ production. The short term contract my be as long as one year. A spot sale qualifes as a

Jan 1, 1986

By R. Hogg, E. Kaya

The presence of agglomerated particles in airborne dust in coal mines has been confirmed by SEM examination of static samples collected on substrates. In addition, the effect of agglomerated particles on the performance of cascade impactors and cyclone- type personal samplers has been studied. Simple procedures have been developed for evaluating the extent of agglomeration in air-borne dust by comparing the observed size- selectivity of the sampling devices with that expected under idealized conditions. Applications of these techniques in the laboratory and in underground mines are discussed.

Jan 1, 1992

By G. Fehr, B. B. Panda, R. Bansberg, K. Arnold, T. Freiman

To evaluate the potential for process solutions to contaminate groundwater outside of the area of the Oxide Pit, it is necessary to predict the ultimate maximum pit lake elevation once pit-related mining activities have ceased. A water balance model was developed based on the existing pit geometry, the groundwater flow equation, and assumed hydrologic input parameters. The model assumed that at any point in time, total inflow into the system (i.e., direct precipitation, surface water and groundwater) minus outflow from the system (evaporation from the lake surface) was equal to the change in the pit water volume. The pit lake depth over time was predicted by assuming a succession of steady- state water balance conditions over short time increments. An analytical method using a spreadsheet and computer model was employed in this study to model the filling of the lake in the Oxide Pit. A sensitivity analysis was performed to evaluate uncertainty associated with the input parameters in the model. The sensitivity analysis indicated that the model was most sensitive to values of precipitation and evaporation and to the static water table.

Jan 1, 2003

By A. Haghighat, B. Lattimer

"Mine face ignition due to a high levels of methane is one of the most common fire incidents in underground coal mines. This work exams ignition scenarios in continuous miner headings. Depending on the magnitude of the ignition or resulting fire, the ventilation curtain in the continuous miner (CM) heading may be damaged or dislodged, affecting the ventilation into the area. A computational study was conducted to investigate the effects of different levels of damage to the ventilation curtain on the ventilation flow into the CM area. The computational fluid dynamics software Fire Dynamics Simulator (FDS), Version 6.0 was used to predict the conditions that develop due to a 200 kW fire in the coal mine face following a methane ignition with different levels of curtain damage. Smoke layer depth, temperatures and mass flow into the CM area were used to evaluate the impact of no damage to the curtain, partially dislodged curtain, and fully removed of the curtain. Partial removal of the curtain allowed more smoke to accumulate in the CM area and a reduction in ventilation into the CM area. With full removal of the curtain, the smoke accumulated through the entire depth of the CM area and flowed out the entrance to the CM area and the ventilation completely bypassed the region. INTRODUCTION Active working faces in underground coal mines are one the most hazardous locations in terms of fire events. According to Mine Safety and Health Administration (MSHA) data analysis, the highest number of non-fatal fire incidents was reported at mining faces, intersections and crosscut areas in comparison with other locations from 2000 to 2012. About 464 fires happened at active working faces from 2000 to 2012, most consisting of a methane ignition, in some cases followed by localized fire. These are high risk incidents due to the potential to raise float dust and damage ventilation systems, particularly auxiliary systems such as curtain or tubing. Depending on the magnitude of the ignition or fire, the ventilation curtain in the continuous miner (CM) area may be damaged or dislodged, affecting the ventilation into the area. Five computational fluid dynamics (CFD) scenarios were considered to investigate the smoke layer depth, temperature, visibility, mass flow rate, and the behavior of airflow in an entry with a continuous miner (CM) located in it. The state of the auxiliary ventilation was varied based on the assumption that as an ignition increases it magnitude it will affect ventilation curtain proportionally. Visibility and temperature along the height of the entry at different sections were investigated and the interface height at each section was determined. Also, the fresh air height was studied for tenability analysis in future. FDS, Version 6.0 was used to predict the conditions that develop due to a 200 kW fire on the coal mine face following a methane ignition with different levels of curtain damage. Smoke view software was used as the post processor to visualize and analyze methane fire behavior at the face. Most entry fires are reported as fuel-controlled fires as they are rarely restricted to air access (Ingason et al, 2014). The working face fire in the following models was assumed to be a fuel-controlled fire."

Jan 1, 2016

By Osvaldo Bascur

Large metallurgical complexes have more data than a small city and much of it is "real time," changing rapidly as internal and external conditions evolve. As corporations buy and sell assets and reengineer their staff, the structures and tools that were used to understand these data are lost. This results in significant deterioration in the ability to maintain a "smart" operation. The solution is to use the sophisticated new tools built for the Internet so as to leverage information in a familiar browser format that people can use and understand. This paper describes the use of Internet technologies with plant data. Examples are drawn from existing industrial sites. Users must project where this technology will lead - standing still is the most dangerous philosophy and the only one guaranteed to be obsolete. These examples show the way to leverage existing workers with information technology.

Jan 1, 2000

By P. J. Bethell

This paper reviews current fine coal cleaning circuitry, including water washing cyclones, tabling and froth flotation. It goes on to examine possible future beneficiation based on emerging technologies. Circuits considered include those incorporating spirals, fine heavy medium cycloning, hydrosizers and column flotation.

Jan 1, 1988

By Shosei Serata

In the past, salt cavities for storage of liquid and gaseous fuels have been developed and operated using practical experience as a guide rather than rock mechanics principles and practices. Although many salt cavities are still operating satisfactorily. some of them are beginning to show various problems associated with long-term deterioration of the cavities. This paper describes a major breakthrough in the rock mechanics design of solution cavities which is the development and application of the REM computer simulation system. From the computer simulation analysis, the long-term deterioration process of cavities can be related to the basic parameters of rock mechanics design and the storage operations. The computer simulation system is also used for optimizing cavity design and operational specifications. This optimization technique is explained by its application to the three basic storage systems: 1) open dry storage system for liquids and solids 2) open wet storage system for liquids 3) pressurized storage system for gases, liquids and solids The effectiveness of the optimization technique is illustrated with some field examples by showing the direct interaction between the computer simulation system and field data of a test well including tectonic stress conditions, material property coefficients and geological anomalies.

Jan 1, 1974

By P. Riveros, A. Pratt, G. Deschênes

The effect of pyrite, pyrrhotite, chalcopyrite, realgar and arsenopyrite on gold dissolution in cyanide media was investigated. The cyanidation of synthetic gold ores in the presence of various concentrations of sulfides was studied under constant experimental conditions. A mineralogical analysis of the minerals was performed. The leaching kinetics were determined. The negative effect of sulfides on the gold dissolution rate varies with the sulfide mineral and decreases according to the following order: realgar > pyrrhotite > chalcopyrite > pyrite > arsenopyrite. The chemical characterization of gold and sulfide minerals surfaces using X-ray photoelectron spectroscopy (XPS) was undertaken to identify the mechanisms involved. XPS analysis showed that a passivation layer of sulfides, arsenic or iron compounds might form on the gold surface as a result of the dissolution of the sulfide minerals. Key words: Gold dissolution, Cyanidation, Effect of sulfides, Leaching kinetics

Jan 1, 2003

By James Wm. White

Mine management now recognizes the value of computer-based truck-shovel dispatching in open pit mines. The key tangible benefits are substantial productivity increases with a given fleet of equipment or, alternately, significant reductions in equipment required to meet production quotas. In this work, we review the literature, report on efficient, optimal algorithms for haul truck dispatching in real-time, and briefly discuss methods used by various mines to evaluate productivity improvements over manual methods. We also present actual results obtained at thirteen mining operations around the world.

Jan 1, 1992

By M. L. Sharrah

Communication about the energy problem has come at us in great profusion during the last couple of years--reports, speeches, editorials, advertisements--and events. Events such as the Arab embargo on oil exports which vividly demonstrated the world's dependence on oil, a finite and nonrenewable resource. And the three-fold increase in the price of oil which provides a constant reminder of the political and economic implications of dependence on foreign oil. A distinction among countries exists today which was almost inconsequential two years ago--the oil exporting nations and the oil consuming nations. The only rational way for the consuming countries to lessen the political and economic clout of the OPEC group is to reduce their dependence on oil. The United States is capable of playing a significant part in such a move for several reasons.

Jan 1, 1975

By R. D. Schmidt, M. J. Friedel

Unsaturated permeability and flow capacity exist where copper mineralization is disseminated in segmented, very-low-permeability ore blocks. The US Bureau of Mines (USBM) investigated this condition for application to in situ, copper-leach mining at the Cyprus Casa Grande mine site. Moisture retention properties are derived and combined with scanning-electron-microprobe data to characterize the host rock's mineralogy, texture, pore size, distribution and permeability. Finite element modeling is used to estimate saturated permeability and the ambient degree of saturation and to gain insight into appropriate in situ leach design. Recommended design modifications for optimized solution distribution and maximum recovery from the Casa Grande ore require: • well pressure injection exceeding 1500 psi and recovery wells operating in a suction mode, or • secondary, permeability enhancement by explosive rubblization. In the former, the lack of conditioning and the use of lesser pressures will result in leach solutions confined to the macrofractures. With the latter requirement, pressures can be reduced to 500 psi, with improved recovery and solutions containment.

Jan 1, 1993