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By Yi Yang, CHENGLONG XU, HAORAN LI, YALI FENG, JINRONG JU

Steel slag is an industrial byproduct of steelmaking that is mainly composed of calcium, iron, silicon and magnesium. In addition, depending on the different raw materials entering the furnace, steel slag contains a certain amount of vanadium that is the main source of vanadium production, accounting for 69 percent of the species of the total vanadium raw material [1]. From experience, the production of one ton of steel will generate 1.0 to 1.5 tons of steel slag [2]. However, the utilization efficiency of steel slag is less than 30 percent, and a large amount of steel slag is identified as waste and stacked in tailings. The random stacking of steel slag not only wastes large amounts of limited steel and land resources but also exerts pressure on the environment [3], making it imperative to research the effective utilization of steel slag and recycling of metal resources.

By K. H. Lee

The rate of beryllium dissolution from a low-grade ore was studied in sulfuric acid solutions. The effect of stirring speed, sulfuric acid concentration, particle size and temperature on the rate of dissolution of beryllium was established. The results of the study showed that the dissolution rate is independent of stirring speed within the range of 250-1000 rpm but depends on 1/2 power of the sulfuric acid concentration. The dissolution rate increases exponentially with decrease in particle size and the maximum attainable rate of extraction with respect to particle size is 6.6 x 10 mol dm min. The apparent activation energy (^E) for the dissolution reaction is 54.4 kJ/mol (13.0 kcal/mol). Based on this magnitude of the activation energy, it is concluded that a surface chemical reaction is the rate limiting step for the temperature range (70° -100°C) investigated.

Jan 1, 1988

By B. J. Scheiner

The Federal Bureau of Mines has developed a chlorine-oxygen leaching technique for the recovery of metal values from lead-zinc sulfide concentrates. Lead, zinc, copper, cadmium, and silver extractions are in the 95- to 99.9-percent range. During leaching, the zinc, copper, cadmium, and silver are solubilized as metal chlorides, and lead is converted to insoluble lead sulfate. The iron contained in the concentrate is converted to insoluble iron oxide, and a majority of the sulfide is converted to elemental sulfur Minor metals such as copper, cadmium, and silver are recovered by precipitation with zinc dust. Zinc is then recovered from the purified zinc chloride solution by evaporation to dryness; the lead is recovered from the leach residue by brine leaching and crystallization to produce lead chloride. Recovery of zinc and lead metals by fused-salt electrolysis of the chlorides is being studied separately.

Jan 1, 1975

By Aarne Visnapuu

Unmodified pneumatic rock drills may have noise levels of 115 to 130 dB at the operator's position. Experimental modifications have been made to a standard drill to suppress the noise from the three main sources: the air exhaust noise, the noise radiated from the drill, and the resonance noise of the steel drill rods. A prototype model developed at the Bureau of Mines, Rolla Metallurgy Research Center, operates at a noise level below 100 dB. A close-fitting case and muffler unit, consisting of a metallic skeleton filled with viscoelastic absorber and having a durable cover, provided both muffling and noise absorption. Damping alloys were used at strategic points in the drill. Drill steel resonance noise was reduced by a constrained-layer treatment on the outside of the drill rod. The singular and combined effects of the treatments are presented in detail.

Jan 1, 1973

By Katherine Hynard, Colin Eustace

Suboptimal decisions introduced during the mine planning process are generally a consequence of both a myopic view of planning objectives as well as time and resources available to convert longer-term plans into execution plans. Erosion of strategic mine plan value in conversion to execution plans is likely to amount to billions of dollars each year. When integrated with operations data feeds, simulation and optimization tools can be used to preserve the value in the strategic mine plan. Optimization models are capable of both automating production of execution plans and improving performance. This reduces the manual burden of revising plans while improving alignment with long-term production objectives. Simulation models can also support the process of developing effective execution plans by providing forward visibility of mine operations performance. They can also be used to test the robustness of optimized execution plans and response to operational variability and disturbances.

May 1, 2025

By Lloyd M. English

Accurate knowledge of the gas content of coal seams has always been important, according to the work of W. P. Diamond and J. R. Levine, 1981, but is becoming increasingly important for several reasons: Excessive gas emissions in the mine can create explosion hazards. Depletion of shallower coal reserves is forcing underground operations to greater depths where coal gas content is often greater. Natural gas prices and the need for new energy sources make naturally occurring coal gas a potential resource of economic interest. Information on coal gas content will impact mine designs, mine ventilation system specifications, and the effectiveness of methane control procedures used. Accurate resource assessment is needed for projecting and designing potential gas utilization enterprises. The emphasis upon methane hazards in mining operations, and upon potential methane utilization, has led us to improve upon the procedures used to determine coalbed methane levels.

Jan 1, 1984

By Vas Choudhry

The eighties are likely to witness the first commercial-size coal-to-gasoline plant(s) in the U.S., although uncertainty regarding crude prices and cautious involvement of the Federal Government in the synfuels development are evident. The formation of The U.S. Synthetic Fuels Corporation with passage of the Energy Security Act is projected to pave the way for some of the projects on a moderate scale. The corporate objectives (1) are to provide funds for supporting a number of feasibility studies and loan guarantees for the construction of at least some commercial-size plants and the possibility of product price supports or purchase commitments. There are a number of coal conversion processes (2) currently under evaluation for producing either gaseous or liquid plus gaseous fuels, the other processes such as SRC I are for producing desulfurized deashed clean solid fuel for commercial use.

Jan 1, 1982

By James E. Lawver

During 1981 the Florida phosphate industry produced more than 43 million metric tons of phosphate rock - about one-third of the entire world production and also generated nearly an equal amount of waste clay and waste clay-sized product that requires dewatering and disposal. The material balance of solids and water for a typical Florida phosphate mining operation is shown in Figure 1. Historically, the industry has impounded clay waste (about 60% below ground and 40% above ground) in earthen dams, often as large as 800 acres and occasionally greater than 60 ft. high. The dams have served the triple purpose of: 1. Dewatering initial 3% solid waste clay for process water re-use. 2. A reservoir system to minimize water discharge from the mining area and to capture and store rainwater thus minimizing deep well pumping requirements. 3. The ultimate densification and storage of waste clay.

Jan 1, 1983

By d&apos, J. A. Oliveira, A. K. L. Resende, L. F. G. Assumpção, J. D. Neto

Kaolin samples from Rio Capim Resources were treated in conventional and superconducting magnetic separators to study the main variables that influence the impurity removal process. Two coating clays and a delaminated clay were tested. The variables studied were retention time (cross-sectional velocity), magnetic-field intensity and matrix type. The feed brightness ranged, from 84.7% to 87.6% ISO, for the coating clays and ranged from 80.7% to 85.4% ISO for the delaminated clay. Using a conventional magnetic separator with an applied, field of 1.5 to 2.0 T (tesla), the brightness values were higher than 88% ISO for the unleached coating claw products and were higher than 87% ISO for the unleached delaminated product. With a maximum field intensity in the superconducting machine of 5.0T unleached brightness values higher than 88.5 % ISO were attained for both coating and delaminated clays.

Jan 1, 1997

By Richardo Montoya

Radomiro Tomic, the new CODELCO division, is a copper deposit located at 3000 m a.s.l. and 40 Km from Calama in northern Chile. It has total oxide reserves of 802,000,000 tonnes with an average grade of 0.59% total Cu (using a cut-off grade of 0.4% total Cu). The copper oxide ore is mainly atacamite and chrysocolla. Startup is expected to commence in December 1997 of 150,000 t/y of Cu cathodes. Future expansion to 250,000 t/a of Cu cathodes is currently being planned. The process consists of an open-pit mine, a two-stage crushing system, agglomeration with sulphuric acid and emplacement on a heap leach pad for a 45-day leaching cycle. Solvent extraction and electrowinning will produce LME "A grade cathode. A number of significant technology innovations have been incorporated into the project.

Jan 1, 1998

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 MSHA

Not quite a year ago, during a speech to a group of mining professionals in Washington, DC, the subject centered around the long-range importance of conducting research projects and how much that research needs to specifically apply to health and safety matters in our industry. The point was made about the critical need to work together with government, private industry, labor organizations and academia speaking with a unified voice as we all march into the future together. The fundamental benefits of competitive research were mentioned -- to improve our quality of life, to develop our energy resources, to achieve a safe and healthy environment and to ensure long-term economic growth. Very importantly, emphasis was given to the natural link that makes my agency, the Mine Safety and Health Administration, and the National Institute for Occupational Safety and Health -- NIOSH -- the beneficiaries of each other's findings.

Jan 1, 1999

By Mark L. Mott, Michael P. Synder

The Mine Safety and Health Administration has developed a program to improve the decision making process of personnel involved in mine emergency situations. The Mine Emergency Responsiveness Development Program (MERD) has been designed specifically for fires and explosions in underground mines. This program addresses the responsibilities and organizational requirements that are necessary during rescue and recovery operations of a mine emergency . Specific skills and knowledge are required to manage an organization of personnel under conditions of intense stress, such as a mine fire or explosion. As a result, the MERD program develops these skills by providing role playing emergency simulations. This role playing provides the participants with the opportunity to experience problems, explore solutions and interact with other personalities which may exist during mine emergency situations. This paper presents the standard procedures for the MERD program developed by the Ventilation Division of the Pittsburgh Health Technology Center.

Jan 1, 1991

By Rod Knopp

Each year approximately 5,000 tons of a sulfide concentrate grading 1 ounce gold per ton are produced at this operation. The material is refractory and as shipping costs and custom smelter charges increase, options to process it on site are becoming more attractive. Three methods of treating the ore have been investigated in detail. The first option of ultra fine grinding the concentrate produces a 35% gold recovery with relatively low capital and operating costs. A second option of pressure oxidation is very capital intensive and has high operating costs but recoveries in the order of 95% are achievable. The final option, biological leaching offers both capital and operating costs which are less than pressure oxidation, while still achieving 90% gold recoveries. Bioleaching of gold concentrates has been gaining acceptance but there is a risk factor associated with this or any emerging technology.

Jan 1, 1990

By Matthew J. Hrebar

A comparison of hydraulic shovels (HS) versus front-end loaders (FEL) is commonly made when an excavator with some degree of mobility and medium reach is required. These applications are often found in hard rock open pit and surface coal mining applications, among others. The purpose of this paper is to present a comparative economic study of the two excavators. Production data was collected from both HS and FEL manufacturers as well as operating mines. Availability, operating costs, and estimated operating life were gathered from operating mines, while capital costs were obtained from manufacturers. The data was limited to studies and operations which included both types of mid-size excavators. The economic study is followed by a discussion of other factors considered by mine operators in excavator selection. The study was originally made for a presentation at the 23rd Intermountain Minerals Conference at Vail, CO.

Jan 1, 1992

By John Pekrul

Coeur Rochester Inc. located in north central Nevada, operates an open pit mine moving a total of 16 - 18 million short tons of material per year. A three stage crusher produces approximately 8 million tons of a minus half inch product that utilizes truck stacking to construct a heap leach with a zinc precipitation recov­ery plant. Coeur Rochester recovers approximately 6.0 - 7.0 MM ounces of silver and 60 - 80 K ounces of gold annually. Current metal prices and good operating practices require contin­ued review of operating systems that support the operation, thus the development of a Strategic Mine Plan. This Strategic Mine Plan provides managers, engineers and supervisors a means to improve their operations through three main objectives: 1. Reduce operating costs, 2 .. Increase production, 3. Increase mine life (reserves). These three main objectives will be reviewed in context to their current status and past performance.

Jan 1, 1999

By Q. Yuan, B. Yarar

Steric stabilization is a phenomenon observed when relatively high doses of flocculants are added to fine particle suspensions. Experiments were conducted to establish conditions under which medium viscosity and the sedimentation properties of black sand components in a slurry could be controlled so as to enhance the selective sedimentation of gold grains. It was shown that black sand concentrates containing as low as 2.65 g/mt gold could be upgraded by selectively hindering the sedimentation of non-gold components in an aqueous slurry. This paper presents data describing the theory and practical implementation of this cyanide or mercury-free novel approach where gold could be concentrated by as much as 15 times with relatively high recoveries. The relationships of solids content of slurries, type and dose of polymers with the recovery process are documented. Key words: Gold, black sand, selective flocculation, steric stabilization.

Jan 1, 1993

By V. Angelatou

In the present study, the possibilities of use of natural zeolitic tuffs from the Skaloma area, Rhodope prefecture, Greece, for the removal of Pb and Zn ions from aqueous solutions has been studied. The equilibrium data were examined for different grain sizes, pH?s and initial concentrations. An apparent kinetic study was also carried out for different time intervals at constant temperature and pulp density. For the chemical equilibrium study the Freundlich isotherm was used. The experimental results verified the favored behavior of zeolite on lead ions and the quick kinetic of the process whilst the efficiency of the ion exchange on zinc is rather limited. The grain size of the material did not greatly affect the performance of the process. The removal of metal ions worked better at lower pH. The Freundlich isotherms are in good agreement with the experimental data.

Jan 1, 2006

By Betty L. Gibbs

The ultimate objective of mine design is to determine the development and untilization of mining resources. Computer Aided Design (CAD) and automated mapping are becoming very popular in engineering and in mining. Any computer program which produces a design or model with the interaction of an engineer can be considered computer-aided design (CAD), but' the term CAD is often associated with interactive graphic design and mapping capabilities. Graphics can be effectively used to describe and model two-or-three dimensional mine workings, orebodies, and geologic structures. Interactive computer graphics is applied to mine design with a combination of deposit modeling techniques and the use of AutoCAD for interactive graphics and mapping. The combined system can perform a large part of the calculations and drafting work for geologic and mining design. Using computer calculation and graphics techniques, comparisons of alternatives, can be made quickly.

Jan 1, 1989

By G. Capello

Carboniferous mining basins are today a non-negligible source of energy. So important in fact that returns now justify high investments and costs even for those deposits that were un-economical in the past. Nowadays, if properly explored and exploited, basins previously considered non-minable due to complex structural and stratigraphical situations may be economically interesting. It is while studying a faulted basin with such features that the Authors developed the described computer-aided methodology capable of constructing a model of the physical structure of coal deposits on the basis of stratigraphical data from drillings. The aim of the procedure is to define coal reserves, the exploitation of a deposit being conditioned by the possibility of identifying zones that are technically minable. This objective is pursued by making as detailed a reconstruction as possible of the geometrical, stratigraphical and tectonic features of the coal-bearing seams of a deposit.

Jan 1, 1982