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By F. H. Deist, M. P. Roberts

"The Collieries Research Laboratory of the Chamber of Mines of South Africa is developing a coherent system of programs to aid in the full spectrum of activities arising in the planning of new as well as operating mining enterprises. It is the purpose of this paper to describe the design and application of two subsystems in the complex.One of these subsystems is an initial version of a production simulator. This program draws upon a model of a mining enterprise and simulates the operational and financial aspects of a set of alternative mine production plans.These plans are specified in terms of proposed sequences of operations. Details such as reserves, production rates, resource requirements and so on, are taken from the model.Physically, the model takes the form of a cross-referenced data base, maintained by means of a general file maintenance system which is another subsystem described.The paper concludes with a description and analysis of the first practical application of the two programs."

Jan 1, 2014

By Russell Griffin

The current state of the art of fire and smoke detection technology is reviewed from the standpoint of suitability for use in under- ground metal and nonmetal mines. Detection modes, fire signatures, and environmental considerations are included. Preliminary results of long- term, in-mine tests are presented.

By Carl Bertrand, Patrice Nadeau, Claude Bazin

"Rio Tinto Fer et Titane processes the ore extracted from the Lac Tio orebody to concentrate the hemo-ilmenite (FeO.TiO2-Fe2O3) mineral that is subsequently smelted to produce pig iron and titanium oxide slag. The ore is crushed, heat treated (roasted) and concentrated using dry magnetic separators. This paper describes a model to predict the magnetic susceptibility of the roasted ore and its behaviour in the magnetic separation plant. The model uses a classification of the ore as a function of the size and magnetic susceptibility of the particles. A subsequent division into mineral species allows the simulation of the magnetic separation process. The model is used to assess various operating options when process disturbances occur.INTRODUCTIONOre processing operations consist of ore size reduction followed by the recovery of valuable species in a concentrate that is subsequently sold for its minerals or metal content. The concentration processes are based on the physical and/or chemical properties of the minerals contained in the ore. Flotation is typically used to recover minerals of base metals such as copper, zinc, lead or nickel. Iron ore and other dense minerals are typically concentrated by gravity separation processes. Magnetic separation uses the magnetic properties of the minerals to concentrate magnetite and other minerals, to clean coal concentrate and to recycle ferrosilicon for dense separation processes (Brophy, 1985).Magnetic separators can be divided into low and high intensity separators and high gradient magnetic separators (Gillet, 2008). Most of the low gradient magnetic separators are built as rotary drums that are operated in wet or dry conditions. Dry magnetic drum separators are used by Rio Tinto Fer et Titane in Sorel-Tracy, Canada to concentrate hemo-ilmenite from the ore extracted at the Lac Tio Lake mine near Havre St-Pierre, Canada. The analysis of production data suggests that process improvement could be achieved by identifying key variables for the control of the magnetic separation circuit and/or by modification to the circuit flowsheet. The use of a process model was considered to be an effective approach to conduct a preliminary analysis of the circuit with a view toward process optimization. However, the literature contains few detailed studies dealing with the modelling of magnetic separation processes."

Jan 1, 2011

By P. A. Kennedy

An environmental assessment or impact statement for onshore waste disposal under the Notional Environmental Policy Act is expected to occur with the development of commercial deep seabed mining. An environmental assessment was conducted in order that testing and refinement of nodule waste disposal techniques can he completed prior to 1988, when commercial seabed mining can begin under U.S. legislation. Within this study three classes of process and four classes of waste disposal technique were identified, and five sites were selected as representative of first-generation nodule operations. Each realistic site/process/disposal technique combination was compared against potential effects to determine important characteristics of the rejects and the sites. Regulatory requirements were also considered at each site to identify important issues and their effect on the permitting process. Principal conclusions in the report are the following: (1) uncertainties exist in the regulatory regimes for hydrometallurgical process tailings, primarily regarding classification as hazardous waste; (2) slogs from nodule processing are expected to be inert and relatively easy to dispose of at all sites; and (3) additional physical and chemical information on properties of rejects from all processes is necessary to predict environmental effects.

Jan 1, 1982

By C. R. Kuzell

This paper, describing the concentrator practice of the United Verde Copper Co., is one of a series being prepared by the Bureau of HISTORY The United Verde concentrator was constructed in accordance with recommendations based on certain novel reasons which were quite different from those usually justifying the expenditure of such an amount. Concentrator operations started in March, 1927, although the metallurgical staff had considered for several years the eventual addition of a concentrator department.

Jan 1, 1930

By Grafton Thrasher

For the proper discussion of this subject it is necessary to incorporate in this paper the substance of part of an article published by rite in Metallurgical and Chemical Engineering for January, 1915. CAST-IRON TEST PLUG, SHOWING LOW MOTTLED AND MOTTLED FRACTURES. Several years ago, while I was thief chemist for a malleable-iron company, it occurred to me that the mere regulation of silicon was not sufficient to produce the desired degree of chill. But only after repeatedly encountering this fact in befit open-hearth and air-furnace, as well as cupola metal, was I led to regard variation in the total carbon as the principal cause of disturbance; and I resolved to determine the total carbon as well as the sill on ill every heat, and by a carefully prepared test piece to gauge the approximate degree of chill. The test piece selected was a round plug, 2 in. in diameter and 12 in. long, cast on end

Jan 10, 1915

By M. T. Styles, E. Condliffe, R. C. Leake, R. J. Chapman, D. J. Bland

Paper presented at Mineralisation in the Caledonides, the Mike Gallagher memorial meeting held in Edinburgh, 27-28 June 1996. Quantitative point analysis and microchemical mapping identified 52 different types of mineral in inclusions, usually ranging in size from 5 to less than 1 micrometre, inherited from source bedrock. A combination of grain chemistry, heterogeneity and inclusions provides a grain signature reflecting the type and history of source mineralisation. Several grains from an alluvial site are needed, to allow for bedrock variation and the presence of inclusions in only 10-20% of grains. A total of 1 530 grains obtained from 30 localities in Scotland were of ten types, two of them minor variants. Two types in the Highlands may be related to centres of Caledonian igneous activity, but the most widespread is likely to have been of deep-seated origin and structurally controlled. Gold in the Ochil Hills is probably from a source associated with Devonian andesitic activity. In the Southern Uplands, grain types reflect two separate episodes of mesothermal lode gold mineralisation and relationships with Permian red beds/mafic volcanics and with Tertiary dykes

Jun 19, 1905

By A Giblett, K Afewu

This paper uses a case study to demonstrate best practices techniques for predicting the contribution of gravity concentration in a gold recovery process flowsheet. The case study was selected as an example of an ore with a marginal gravity gold content, which makes the value of a gravity circuit difficult to quantify. In this instance the value of leveraging a significant knowledgebase of operating gravity circuit performance to support the decision making process was demonstrated. This case study analysis serves as a useful demonstration of best practice methodologies supporting decisions to include or exclude gravity recovery in a gold recovery process flowsheet.CITATION:Giblett, A and Afewu, K, 2015. Do we need a gravity circuit or not? A case study in applying best practice, in Proceedings MetPlant 2015, pp 288–295 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Paul C. McWilliams

The U.S. Bureau of Mines has, primarily through its contract program, used large-scale centrifuges to determine design criteria for tailing embankments. The centrifuge runs were made at two installations, the University of Cambridge, Cambridge, England and Sandia National Laboratories, Albuquerque, NM. The major problems considered were as follows: slope stability of embankments, modeling erosion and seepage, use of the phreatic surface level to ascertain the validity of centrifuge modeling, and the effects of compaction and weathering on a tailings embankment. This report summarizes the results of the four test series conducted at University of Cambridge and Sandia National Laboratories. A review of prior centrifuge applications to mining problems is included. Consideration is given to future centrifuge application to mining problems in both soil and rock mechanics.

Jan 1, 1989

By K. Hanna

This U.S. Bureau of Mines report describes a rock mechanics instrumentation program conducted in a shallow underground coal mine in central Illinois. This research program was designed to provide a basic understanding of the structural behavior of entry intersections. A wide variety of instruments and measurement techniques including hydraulic borehole pressure cells, multiple-point borehole extensometers, roof bolt compression pads, and overcoring were employed to monitor roof stresses, pillar loading, strata movement, floor heave, and bolt loading before, during, and after intersection development. A summary of intersection design theories, failure modes, and support techniques is included and instrumentation installation procedures and analysis methods are presented. The study identified two critical parameters that affect intersection stability: in situ horizontal stresses and geological discontinuities. Important design parameters for improving intersection stability are roof span and intersection geometry.

Jan 1, 1991

By Tapio Leskinen

"In the 1960’s, when large flotation machines appeared on the market, this was a part of a world-wide trend towards the use of ever larger machine units.One factor that has played a decisive part in this development is the increased of the amounts of ore that have to be handled as the exploitation of successively poorer ores becomes necessary. The advancing application of instrumentation and automation has worked in the same direction.In 1970, a working group was set up within Outokumpu Oy, for the purpose of flotation machine development. The principal task of this group was to be the design and development of- a new type of rotor of increased efficiency, especially for the dispersion of large amounts of air- a mechanical-pneumatic flotation machine of substantially larger size that existing plant.This development project required an extensive program of theoretical investigation and experimental studies at several concentration plants of the company.The commonest flotation machine presently used in the concentration plants of Outokumpu Oy is the VK-3. It is of the mechanical-pneumatic type, and the volume of its cell tanks is 2.5 m3 per shaft. This machine was developed within the company, and its first development phase i s represented by the OKKO 3, built for the Kotalahti concentrator in 1959. It was, in its time, comparable in volume to the largest machines that were then in use anywhere in the world."

Jan 1, 1976

By Segnit E. R

Results are reported of a study of the reactions occurringin the combustion of chaIcopyrite particles underconditions simulating those in the shaft of a flashsmelter.The reactions were studied using kinetic and mineralogicaltechniques. Reactions. rates above 500°C wererapid, most of the reaction taking place in less than 50ms. Final products were copper-iron ferrites with spineltype structures. Probable reaction mechanisms are discussed.

Jan 1, 1977

By Laszlo Toth

A feeder is used to control the gravity flow of bulk solids from storage areas, like a bin or a stockpile. For this type of application, it is important to select a proper drive that can fulfill all of the demands put on it. High starting torque capacity, variable speed and the ability to handle frequent starts and stops are some of the demands that the drive must be able to meet. The following is a comparison of the most common type of drives used today for feeder applications. When a feeder is started, the breakaway torque may reach as high as200% of the running torque. The accelerating torque usually is set to protect the carrying element of the feeder, like the belt for the belt feeder and the carrying chain of the apron feeder (Fig. 1).

Jan 1, 2003

A systematic study of groundwater conditions at eight underground mine sites exhibiting a wide range of groundwater qualities throughout Australia has been completed at the WA School of Mines. This has resulted in a new corrosivity classification for groundwater driven corrosion processes for cement grouted cable strand used in the Australian underground mining industry. The new corrosivity classification is simple to use and corrosion rates may be predicted from readily obtained in situ measurements of groundwater dissolved oxygen.

Jan 1, 2008

By M. Djivre, T. Eger, A. Godwin, I. Bhattacherya

Load-haul-dump vehicles (LHDs) are extensively used in underground mining, however, equipment design and operating conditions contribute to restricted operator sight lines. The inability to clearly see people, objects, or hazards around the machine has contributed to a number of accidents including fatal injuries. In order to identify vehicle design characteristics resulting in restricted and blocked sightlines, line-of-sight assessments are traditionally completed in the field. However, field methods are unable to evaluate lineof- sight under dynamic operating conditions, and are limited in their ability to provide feedback on the impact of various operator characteristics such as sitting height. Results of this research show computer simulation and virtual reality can be successfully used to evaluate line-of-sight during the operation of LHD vehicles. In order to benefit from virtual reality applications, the work environment, LHD vehicle, and human posture need to be represented as accurately as possible. A computer simulation program with ergonomic analysis features, Classic JACK 3.1, was successfully used. Threedimensional CAD models of LHDs were developed from manufacturer specifications and pictures taken from LHDs currently in use. The LHD models were imported into the JACK environment, a digital human was positioned in the cab of the LHD vehicle, and the vehicle and human were driven over a typical mine route. Real-time feedback in the JACK program was used to identify what the operator could see under different operating conditions. Machine characteristics and operating scenarios resulting in impaired line-of-sight were successfully identified with this method. The JACK program could also provide real-time feedback on the human’s joint forces and torques, strength requirements, postural comfort, and metabolic energy expenditure. As a result, this method could be used to successfully evaluate musculoskeletal injury risk factors along with system design recommendations to improve workplace safety and productivity in any setting. The LHDs evaluated in the JACK software package can also be combined with mine models and imported into other VR software packages (e.g. Blender) in order to enable viewing in Laurentian University’s Virtual Reality Laboratory. The VR models using these packages can be viewed in stereo to provide better appreciation of spatial vision issues.

Jan 1, 2005

By C. W. Davie

"This paper is the second of a series of progress reports4 on a study of the hydrometallurgy of manganese which is being conducted in an endeavor to make possible utilization of the large deposits of low-grade domestic manganese ores that occur in several States.There are at least four processes in which a knowledge of the action of SO2 gas on manganese oxides at elevated temperatures may prove of value.One of these involves dissolution of manganese from ores. The Bureau of Mines has investigated the hydrometallurgy of manganese by a process in which SO2 gas, a waste product at many smelters, is passed into water to form a solvent for manganese. Although several manganese minerals were readily dissolved, rhodochrosite (MnCO3) was attacked but superficially.5 Recent experiments have shown that a roast at 650 to 9000 C. converts the manganese of rhodochrosite to a form that is quickly dissolved by a weak SO2 solution.6 Introduction of smelter gases containing much as 5 per cent SO2 during such a roast would not add much to the cost of the operation, and might result in the formation of considerable water-soluble manganese sulpate.Another case involves a subsequent step in the hydrometallurgical process, namely, the formation of oxides of manganese with simultaneous evolution of SO2 by the heating of the MnSO4 produced by evaporating its solution.A third has to do with the roasting of zinc sulphide ores containing manganese as a preliminary to leaching. During purification of the solutions to be used for the electrolytic deposition of zinc the iron must be oxidized to make possible its removal. Manganese dioxide has been used for this purpose,7 and since manganese compounds are present in some zinc concentrates,8 it is of interest to learn what happens to the manganese in a zinc sulphide or on roasting, and what portion of the manganese in the roasted product might be available for oxidation."

Oct 1, 1930

The principle activities of the Explosives Research Laboratory from July 1, 1961 to June 30, 1962, are described briefly in part 1. Part 2 gives short abstracts of publications that appeared during fiscal year 1962; in general, the research reported in these publications antedates the report period. Part 3 gives the results of an investigation which, although too limited to warrant separate publication, merits presentation in some detail because of current interest in ammonium nitrate-fuel oil compositions.

Jan 1, 1964

By Wesley T. Holmes

This report describes the second phase of an investigation aimed at obtaining a wider knowledge of the problems involved in smelting titaniferous magnetites. Liquidus temperature measurements were made on selected synthetic slag compositions in the Ti02 -A1203 -FeO-Si02 -CaO-MgO system. Both the hot-stage microscope and the strip furnace (melting-holding-quenching technique) were used during test procedure to determine the effects of CaO, MgO, and SiO2 on the liquidus temperature of slags. The liquidus temperatures of slags studied ranged from 1,241° to 1,900° C. The lowest liquidus temperature for each Ti02 plus A1203 plus FeO weight-percent generally occurred when the difference between CaO plus MgO and Si02 was less than 12 weight-percent. In this investigation substitution of either CaO or MgO for SiO2 and MgO for CaO raised the liquidus temperature of more than 50 percent of the reported base slags when Ti02, A1203, and FeO contents were held constant. The results of this investigation may serve as guidelines for determining flux requirements in smelting a wide variety of titaniferous magnetite concentrates or ores.

Jan 1, 1968

By L. H. Chen, Y. C. Chen, Leo Benyamin, W. C. Chen

"To investigate the evolution of fluid-driven fracture of rock-like material subjected to borehole fluid pressure and its consequential damage with regard to post-peak stabilization, micro-seismic activities have been monitored using nondestructive technique of acoustic emission (AE) corresponding to the macro-scale complete history of loading curve by setting the hollow cylindrical external circumferential strain to be a closed-loop feedback signal during servo-fluid-driven tests. Development of a novel fluidinduced loading system injected from internal borehole as well as monitoring system were equipped such that the initiation and propagation of micro-cracks enable to analyze experimentally. By programming/controlling either injection rate or fluid pressure, synthetic sandstones with low-permeability made by cement mortar were conducted in this study. It found that both the growth of macro-crack initialized intensively as reaching the breakdown pressure and the micro-seismic activities represented by AE locations show nice agreement. The experimental results in this paper provide better understandings of fluid-driven fracture mechanism.INTRODUCTIONFluid-driven fracture is a process of generating cracks by injecting viscous fluid into solid material. Conventionally, fluid-driven fracture tests have been performed by mining industry to measure the in situ stress (Haimson & Fairhurst, 1969) and fluid-driven fracture has been employed by the petroleum industry to recover oil and gas. Additionally, the mechanism of crack growth or the extension of existing cracks is important to the evolution of volcanic dikes over distances of a few kilometers (Lister & Kerr, 1991; Rubin, 1995), crack propagation in dams (Bolzon & Cocchetti, 2003) and the disposal of radioactive waste (Sun, 1969)."

Jan 1, 2015

By D. J. Boron, R. Kollrack

Introduction The US has the largest total (364 Gt, or 401 billion st) and recoverable (182 Gt, or 201 billion st) coal reserves in the world (Steam/Its Generation and Use, 1978). However, progressive coal use in this country has been hampered by environmental constraints, such as restrictions on sulfur dioxide, nitrogen oxides, and particulate emissions. Since the promulgation of the Environmental Protection Agency (EPA) New Source Performance Standards (NSPS), it has become apparent that all US coals will require sulfur removal to comply with the new sulfur dioxide emission levels. If more stringent emission standards are imposed, through pending acid rain legislation or amendments to the Clean Air Act, it is likely that the coal industry, and the industrial and utility sectors will look increasingly toward the development of new and advanced coal cleaning technologies to continue and promote the use of coal. Table 1 summarizes the EPA NSPS for sulfur dioxide emissions. Fortunately, the basis for determining sulfur dioxide removal is the Btu and total sulfur content of the run-of-mine coal. Thus, credit is given for any sulfur removed before combustion, e.g., through physical coal cleaning. Unfortunately, physical coal cleaning alone may be unable to produce a compliance coal with respect to the EPA NSPS. Therefore, all industrial and utility coal-fired boilers will require post combustion gas cleanup, e.g., flue gas desulfurization (FGD), to comply with the new regulations. Table 1 - EPA NSPS for SO2 Emission Category SO2 Content of ROM Coal SO2 Reduction Required 1 0-2 Ib/M Btu 70 2 2-6 Ib/M Btu To 0.6 Ib/M Btu (70% to 90%) 3 6-12 Ib/M Btu 90% 4 12 Ib/M Btu To 1.2 Ib/M Btu Alternatives to post combustion gas cleanup, such as staged combustion, lime and coal injection, fluidized-bed combustion, and chemical coal cleaning, are currently under development. Of these, chemical coal cleaning offers the advantages of providing (1) high quality fuel for combustion (low sulfur and ash, high Btu, and attenuated product variability); (2) a solid fuel product for use in retrofitted gas and oil boilers; and (3) a solid fuel product with multiple end uses, e.g., internal combustion engines, carbon electrodes, coke, or chemical feedstock. Gravimelt process In the Gravimelt process, 1.4 mm x 0 (14 mesh x 0), physically beneficiated coal of about 5% moisture is fed into a 3401 to 3901 C (644 ° to 734 ° F) molten bath of sodium hydroxide and potassium hydroxide. Organic and pyritic sulfur and most of the mineral matter in coal react with and are dissolved in a molten mixture of potassium hydroxide and sodium hydroxide. The reacted coal sulfur is converted to alkali sulfides and polysulfides, whereas the mineral matter is apparently converted to alkali-aluminum silicates and other byproducts that are water and acid soluble. Coal residence time is 60 to 240 minutes. The sodium hydroxide to potassium hydroxide ratio is about 9:1. The total hydroxide-to-coal ratio is no less than 10:1. The specific gravity of the caustic melt is about 1.8 g/cm3 . Thus, coal is buoyant in the bath, and insoluble mineral matter with density greater than 1.8 g/cm3 would sink. Reacted coal is first water-washed with an equal weight volume of water in a countercurrent mode of operation. The coal is filtered and the filtrate sent for regeneration. The coal is then acid-washed in 10% sulfuric acid. The acid-water/coal mixture is filtered to recover the final coal product, and the filtrate treated with lime to precipitate dissolved mineral matter. The precipitate is filtered from the mixture and discarded. The water is recycled to the plant. Filtrate from water-washing is treated to remove sodium sulfide. The sodium sulfide is chemically treated to produce hydrogen sulfide, calcium car¬bonate, sodium hydroxide, and other products. The hydrogen sulfide is treated to produce sulfuric acid for the acid-washing step. The calcium carbonate is treated further or discarded, and the sodium hydroxide is concentrated by evaporation and recycled to the reactor. The Gravimelt process is currently at the bench-scale stage of development. A 0.9-kg (2-lb) continuous reactor is in operation with a continuous water- and acid-washing section adjacent. The regeneration section is not developed to a meaningful extent, although key reactions have been tested in the laboratory. Process conditions, product recovery efficiencies, etc., however, have not been determined adequately and continuous regeneration operation has not been attempted. Work is now in progress to develop each section to a continuous bench-scale operation in processing coal at 9.1 kg/h (20 lb per hr). Microwave process The carbon and hydrogen in coal are relatively transparent to microwave radiation. However, water, caustic, pyrite, and other mineral matter components are strong conductors of microwave radiation energy at the proper frequency. As a result, selective heating of the noncarbonaceous materials occurs that enables the chemical reaction of sulfur and ash with caustic. Although very high temperatures may result from

Jan 1, 1987