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By Éric Létoumeau, Julie Fournier, Sylvain Caron, Yves Breau, Martin Plante, Dominique Girard, Luc Tardif, François Robichaud

"Since 1999, COREM (formerly the Centre de Recherche Minérale) has conducted and coordinated research and development activities for a consortium of mining companies that uses the benefits and advantages of collaborative pre-competitive research. In particular, COREM’s “In Situ Optimization Group” is involved in the development and implementation of modem information technologies related to process optimization and control.The POP Project was launched in order to increase and consolidate the use of such technologies applied to mineralurgical and metallurgical processes. To ensure a successful transfer to the industry, there are a number of essential activities that have to be undertaken. These activities have been identified by COREM’s members and are grouped into three main modules:- R&D Module: research and development in universities and research centres;-Technology Transfer Module: integration of new tools into the POP Software, industrial applications and technical support;- Training Module: education of new engineers in universities and continuing education of plant personnel through on-site workshops.This paper outlines the opportunities that led to the definition of the POP Project, presents its main objectives and describes its main modules. The main features of the POP Software are outlined, the first applications at COREM’s member plants are presented and, finally, future developments are discussed."

Jan 1, 2002

By Zhang Baoshan

In this paper, the forced features and dynamic behaviors of stone-column composite foundation are concisely related. The characteristics of Rayleigh wave method is summarised. This method is proposed in which, the stress ratio of the stone-column to the surrounding soil and the bear­ing capacity of the composite foundation are determined. Through the engineering cases, it is shown that, checking and evaluating the composite foundation in this method, is feasible, with high speed and low cost.

Jan 1, 1991

By M. Dobbins

The advent of the more efficient and effective rare-earth roll (RER) separator in the early 1980s began a new era of dry magnetic separation. The RER units quickly became the separator of choice within the materials processing industry. Though RER separators are now commonplace throughout the world, only modest advancements have been made to the original design. This paper details recent, more significant, rare-earth magnetic separation developments. These developments maintain the best features of existing technology while minimizing shortcomings. The discussion includes discerning features that aid in better metallurgical performance. Also discussed are improved mechanical aspects that allow for both easier operation and maintenance. Performance details from various test programs are included.

Jan 1, 2010

By M. A. Trevits

The National Institute for Occupational Safety and Health (NIOSH), in partnership with the Mine Safety and Health Administration (MSHA), is conducting research to test, evaluate, improve or modify coal mine fire-fighting strategies and methodologies through large-scale tests. Since wood is the second most abundant fuel available during a coal mine fire, it was decided that series of large-scale wood crib fire tests were needed to measure the products of combustion and to observe the capability of commonly available direct application fire suppression equipment, namely, fire extinguishers, water and gas-enhanced foam. This paper discusses the wood crib fire tests, provides insight into the products of combustion and describes observations made during the application of the fire suppression agents.

Jan 1, 2009

By Laurance L. Oden

The Bureau of Mines is developing melting data for binary combinations of the alkaline earth fluorides and yttria to facilitate the formulation of slag compositions. The present report deals with the CaF2-Y203 system for which solidus and liquidus temperatures and solid solubilities were determined. The information is presented as the phase diagram. All specimen compositions were blended from high-purity materials and encapsulated in Mo or Pt20Rh prior toheat treatment. Liquidus temperatures were determined by ceramographic examination of heat-treated and quenched specimens. Solidus temperatures were determined by differential thermal analysis and by electron microprobe analysis of quenched specimens. Terminal solid solubilities were derived by parametric methods. The peritectic system was found to be pseudobinary due to the formation of yttrium oxyfluoride at temperatures near the liquidus. The peritectic point occurs at 7 mole pct Y203 and 1,438° ± 5°C. The terminal solid solubility of Y203 in CaF2 decreases from 7 mole pct at 1,438° C to 1 mole pct at 1,100° C, and the solubility of CaF2 in Y203 decreases from 9.5 to 7 mole pct over the same temperature interval.

Jan 1, 1970

By J. C. van Dyk

The objectives of this study were firstly to characterize and quantify the inorganic material in the Secunda gasification feedstock. Secondly, the effect of washing on coal properties and sulphur content was investigated. Coal from a single source and a coal blend from 6 different mines were tested. Composite samples were visually sorted by a geologist in the groups containing roof, floor, C-shale, pyrite, carbonates and siltstone material. Inorganic mineral types from the single source and coal blends were characterized separately. Characterization results indicate that the average mineral matter distribution (mass %) of the coal tested was as follows: carbonates (6%), carbon-shale (19%), pyrite (12%), roof (18%), floor (46%) and siltstone (22%). The roof, floor, pyrite, carbon-shale, carbonates and siltstone in the single source and coal blend have similar chemical properties and characteristics, except for the ash melting temperatures of pyrite and kaolinite in the siltstone. By implementing selective mining and increasing mining management practices, the percentage discard in the run of mine coal can be significantly reduced, by up to 45%, if the mining of roof and floor material can be avoided. No significant impact of mining practices on sulphur content is expected in this case due to the low concentrations of sulphur in the roof and floor material. In summary, selective mining practices will probably result in almost45% decrease in the discard content in the run of mine to gasification, an increase in the carbon content from 55.0% to 58% (air dry basis) and a decrease in sulphur content from 1.1% to 0.9% (air dry basis). It is clear from this study that the main source of sulphur is not in the high ash-content mineral types (e.g. floor and roof), but in situ in the coal structure. Keywords: inorganic material, effect of washing, roof, floor, pyrite, C-shale, carbonates and siltstone

Jan 1, 2005

By M. C. Mound, E. Gallestey, C. Colbert

Continuous operating performance and high profit is one of the major concerns in the mining industry. Information systems are expected to reinforce and enable conformance to these requirements. The companion efforts of business management and production information systems press for tighter integration to avoid over-laps, multiple instances of similar data, and expensive maintenance of databases. Implementation of advanced intelligent systems throughout a mine operation can reduce costs, optimize investment and create a shorter payback via conversion of the data accumulated by field and process devices into information, and subsequently, into decisions. However, in order to harness the potential power inherent in these intelligent devices, adequate and flexible modular knowledge-based solutions are required. Fortunately, there has been at least one such practical response to this challenge, namely the ABB IndustrialIT portfolio. With these tools in place, production efficiency is reached via integration of process, production, and quality information. Moreover, they permit immediate detection and remedial action to changes to process and boundary condition variables. Finally, using advanced optimization techniques supported by dedicated mathematical models, they allow for economic process optimization (process set points and coordination thereof, energy management, production planning, energy supply contract optimization, etc) of the plant as a whole.

Jan 1, 2004

By Gordon E. Agar, Brian Lyons, Gregory H. Styles, William B. Kipkie

"Rock rejection during the flotation of a copper-nickel ore was improved by adding carboxymethyl cellulose to both a rougher and cleaner flotation stage. The selection of the rock depressant was based on laboratory rates studies. Plant operating results are presented which confirm the laboratory selection of two particular brands of carboxymethyl cellulose.The rock assay of the concentrate was reduced from more than 40% to less than 15%.IntroductionThe traditional method of selecting flotation reagents relied upon batch bench scale tests, conducted under arbitrary conditions, to identify the effect of the reagent under examination. Too often these were ""one-off"" tests with little or no regard paid to the reproducibility of the results. Sophisticated researchers used statistical methods to design and evaluate the experiments but they were still obliged to rely on the arbitrary and often unreliable batch tests to generate the numbers that were analyzed statistically. An interesting side-effect of the enhanced sophistication of the statistical analysis was often that no significant effects would be uncovered in a series of experiments that would have generated many positive conclusions and much further experimentation if the same results had been evaluated by the traditional method.In the recent past, at least two groups of researchers a have directed their attention to the reliability of the batch experiments with a view toward improving the reproducibility of the test data. In this work the best of the improvements advocated by both of these groups have been adopted in order to generate kinetic data from batch tests that are as reproducible as possible.The objective of the work was to reduce the rock content of a bulk sulphide concentrate produced at Inco's Shebandowan mill. During 1982 the Shebandowan concentrate analyzed 3.5% Cu, 7.4010 Ni, 25% pyrrhotite and more than 40% rock, which resulted in an MgO content of 10.4%. Besides the expense of shipping all of this rock to Sudbury, the rock also contributed to the poor filterability of the concentrate. On favourable occasions the moisture content of the filter cake was slightly over 20% by weight. The magnesia content of the concentrate was deleterious to the reverberatory furnaces used by Inco for smelting nickel concentrate because the slag viscosity increased as the magnesia content increased, and the nickel lost in the slag went up."

Jan 1, 1987

By S. E. Cook

This article uses the case of the Royal Bafokeng Nation to argue that royalties and dividends from mineral resources, if managed well, can provide direct benefits to the surrounding community even while the state collects its share of mining revenues through taxation. The key to this model is the effective management of the resource income flowing into community coffers. Where some of this income may fund urgent interventions in the community, a portion of the income can also be used to establish an intergenerational wealth fund to meet the needs of future generations. As a depleting resource, minerals like gold and platinum are not a sustainable source of income, and must be replaced over time by more regenerative income streams. These strategies and dynamics are manifest in the Royal Bafokeng Nation?s status as both community and quasi-municipality, a labour hosting and a labour sending community, a mine operator and a mine owner. The Royal Bafokeng Nation also owns one of South Africa?s largest community-based investment companies, which channels revenue derived from platinum deposits into a broad investment portfolio that in turn funds an aggressive social development program for 150,000 people living in twenty-nine rural villages.

Jan 1, 2013

South Africa remains the largest global producer of gold, accounting for 11.3 per cent of total world mine production, which amounted to 2520.2 t in 2005. The benefits and disadvantages associated with hedging practices in general, and among South African gold producers is examined. The wide variety and unique nature of risks faced by the mining industries provide a strong case for hedging. Only the principles of hedging, such as selling ounces of gold in the ground at a pre-agreed price for delivery at a future date as a cost-effective mechanism for price risk management, is discussed. Progressive and cumulative increases in the volume of forward sales in the major producing countries are considered by many to be the cause of the declining gold price over the past decade. In spite of negative publicity, forward selling continued as an industry-wide practice until recently (2002) when the global hedge book contracted by 352 t; contraction amounted to 158.6 t in first quarter of 2006. The objectives and benefits of hedging include continuity and stability of cash flows, stability in price achieved, reduction of frictional costs, and creating an effective management tool. The importance of a defined hedging strategy in reducing uncertainty about the hedging objectives is essential to a successful hedging policy. Historical patterns in hedging revenues at an industry level indicate five distinct periods during which the fortunes of hedgers have fluctuated. Finally, since 2001 the rising gold price and reduced price volatility through the consolidation in the global price means that the need to stabilize revenue flows is less urgent. This has meant that hedging is becoming progressively less important for the mining industry at large.

Jan 1, 2007

By M. Al Mukhtar, D. Hoxha, X. Brunetaud, D. P. Do, C. Auvray, L. Michel

"Mechanical behavior of rock joints is often the key factor governing the response of complex structures constructed in fractured rock masses such as underground openings or of objects assembling various stones blocks such as historical building walls or damaged marble statues. This paper aims at developing a theoretical model to describe the behavior of fresh joints based on the description of their morphology. The main idea of the model is to establish a link between the effective contact surface of joints and the frictional coefficient. Beginning from a chosen level of joint surface description where a joint is considered as “smooth”, the model describes the added friction with respect to the increase of the contact surface of the joints and the distribution of stress in these contacts. The model developed initially for asperities with regular geometry is firstly compared with existing models and then applied on fresh artificial joints. For that, healthy artificial joints have been characterised using in one hand classical CNL shearing tests and in another hand the morphology of joints. The joints surfaces are digitized before testing using a high resolution laser scanner (Konica Minelota Vivid 910) allowing to obtain a precision up to 10µm. From these scanned surfaces the morphology of joints is characterised on the profiles running in the direction of shearing and a mean value of friction is calculated using the developed model. This calculated value is then compared with that obtained from CNL shearing test and a good approximation is notedINTRODUCTIONThe role of the mechanical behavior of rock joints on the overall response of fractured rock masses is well established in many fields of engineering activity going from the stability of underground constructions (Souley M, Hoxha D, Homand F 1999), rock slope stability (Einstein H.H. Veneziano D., Baecher GB., O’Reilly K.J, 1983, Jaeger 1971), various rehabilitation of masonry construction, damaged stone artworks restoration (Michel L., Do D.P, Coignard B, Hoxha, 2014) and so on. In the same time the characterisation of the behavior of joints and their modeling is nowadays a dynamic field of research or/and investigations and many alternative approaches have been proposed (Barton, N.R. and Choubey, V. 1977, Tatone, S.A. Bryan, Grasselli Giovanni 2010, William C E. 2007). While empirical relations of shear strength with various parameters of the joint morphology are the most used in practice because of their simplicity (Barton. and Choubey, 1977, Barton 1973, Bandis S., Lumsden A. C. and Barton N. R. 1983) many other models of joint strength are developed based on mechanistic considerations (Haberfield CM, Johnston IW. 1994), multiscale approaches (Yang Z.Y., Di C.C., Yen K.C. 2001, Fardin N., O. Stephansson, Lanru Jing 2001) or micromechanical ones (A. Serrano, C. Olalla, R.A. Galindo 2014) to mention just a few of research trends on rock joints modeling."

Jan 1, 2015

By M. J. McLeod, S. Watters, G. G. Lutes, S. Castonguay

"Gold-bearing mineralization at Anomaly A occurs in polydeformed Ordovician turbidites of the Kendall Mountain Formation of the St. Croix belt in southwestern New Brunswick, and is hosted by WSWtrending, shallow-dipping, brittle-ductile high-strain zones associated with the latest stage of the second of four regional deformation events. Gold-bearing syn-deformational stockwork, massive, and multiply brecciated quartz-sulfide veined zones form irregular pods and sheets up to several meters thick, which contain arsenopyrite, pyrrhotite, pyrite, stibnite, and a variety of rare minerals that are gold-bearing. Mineralized zones are enveloped by locally auriferous, weakly to intensely altered wall rock. Vein paragenesis includes: (1) early (pre- to syn-D2) quartz-chlorite veins that are largely the product of migration of quartz by pressure solution; (2) crosscutting, multiphase, vuggy quartz-sulfide veins that contain most of the gold and are interpreted to be structurally controlled; (3) late, crosscutting, nondeformed, non-gold-bearing veins containing laumontite, chlorite, muscovite, quartz, fluorite, and base metal sulfides. Carbonate-poor alteration associated with zones of gold mineralization is lithology-specific, and appears to reflect overprinting of multiple events. Major elements removed during alteration include Si, Na, Mn, and Mg. The minor and trace elements removed include Co, Li, Sc, and possibly Sr, Ni, and Zn. Minor and trace elements added include Au, Ag, As, Sb, S, and possibly F, Cu, Pb, and Zr. On the basis of proximity, time constraints, and a similar ore mineral assemblage, gold mineralization at Anomaly A is interpreted to be a distal equivalent of the intrusion-related gold mineralization at the nearby Clarence Stream Main zone deposit. La minéralisation aurifère de l’Anomalie A se trouve dans des turbidites Ordoviciennes polydéformées de la Formation de Kendall Mountain, dans la ceinture de Ste-Croix du sud-ouest du Nouveau Brunswick, où elle est contenue dans des zones de déformation fragile-ductile à faible pendage de direction OSO associées au dernier stade du second de quatre épisodes de déformation régionale. Les zones aurifères syn-déformationelles se présentent en forme massive, de stockwork, ou de veines de quartz-sulfure bréchifiées à répétition formant des lentilles irrégulières et des couches de plusieurs mètres d’épaisseur contenant de l’arsénopyrite, de la pyrrhotite, de la pyrite, de la stibine, ainsi que divers minéraux aurifères rares. Les zones minéralisées sont entourées d’une enveloppe de roches faiblement à intensément altérées, localement aurifères. La paragénèse des veines comprend : (1) des veines précoces de quartz-chlorite (pré- à syn-D2) qui sont principalement le produit de la migration du quartz par solution-pression; (2) des veines polyphasées de quartz drusique et de sulfures contenant la plus grande partie de l’or, celles-ci sont considérées comme étant sujettes à un contrôle structural; (3) des veines tardives stériles, sécantes et non déformées contenant de la laumontite, de la chlorite, de la muscovite, du quartz, de la fluorite et des sulfures de métaux usuels. Les zones de minéralisation aurifère sont associées à une faible altération en carbonate contrôlée par la lithologie et semble résulter de la superposition d’événements multiples. Les éléments majeurs perdus durant l’altération sont le Si, le Na, le Mn et le Mg. Les éléments mineurs et traces perdus durant l’altération sont le Co, le Li, le Sc et possiblement le Sr, le Ni et le Zn. Les éléments mineurs et traces enrichis comprennent l’Au, l’Ag, l’As, le Sb, le S et possiblement le F, le Cu, le Pb et le Zr. Étant donné sa proximité géographique, les contraintes temporelles et les similitudes de leurs assemblages minéraux, la minéralisation aurifère de l’Anomalie A est interprétée comme un équivalent distal de la minéralisation aurifère associée aux intrusions du gisement avoisinant de la zone principale (Main"

Jan 1, 2008

By Willard L. Hunter

The research described in this Bureau of Minus report was conducted to improve the chromium-iron ratio of offgrade chromite. Two methods were used: (1) Iron was selectively reduced from chromite by carbothermic reduction in an electric-arc furnace, and (2) a mixture of carbon, chromite, and sometimes fluorspar was chlorinated to remove a substantial part of the iron. Chromite concentrate from the Mouat deposit in Montana and from northern California was used in the test work. Chromium-bearing slag and chromite that had been beneficiated by a roast-leach process were each smelted to produce high-carbon ferrochromium. Iron was selectively reduced in a laboratory-scale., electric-arc furnace. Carbon additions to the smelting charges varied from 40 to 100 percent of the stoichiometric requirement, and slag basicities were varied from 0.4 to 1.0 chromium-iron ratios of more than 4:1 were obtained with 89 percent recovery of chromium in a chromium-bearing slag.

Jan 1, 1962

By Keith Bowers, Frank Mimnagh, Eddie Woods

The CTRL London Tunnels The Channel Tunnel Rail Link (CTRL) London Tunnels comprise 36km of internal diameter bores that were driven by Earth Pressure Balance (EPB) Tunnel Boring Machines (TBMs). The tunnels were constructed between the autumn of 2002 and the spring of 2004. The permanent works also included the 1.1 km long station box at Stratford, five ventilation shafts of depths between 30 and 54 m, 29 cross passages and various large diameter sprayed concrete lined connecting tunnels. The tunnels were driven under densely populated areas of north and east London, as depicted in Figures 1 to 4. Under the parliamentary CTRL Act the project had obligations to make

Jan 1, 2005

By Mehdi Razavi

Scope of the Study The possibility and risk associated with mining two stopes at the same time The influence of Creighton Fault on the stability and dilution The effect of irregular shape of stope walls on overall stope stability and ore dilution The support requirements for proposed mining plan

Oct 1, 2010

By Thomas J. Albin

U.S. Bureau of Mines research has found that maintenance of surface mining equipment is involved in slightly more than one-third (34.1 pct) of all surface mining accidents. Two groups of machines, haulage trucks and power shovels, accounted for over one-half of all surface mining mobile equipment maintenance accidents in 1978-84. Maintenance work-time histories for these machines were compared with accident records to identify the most hazardous-to-maintain systems within the machines. Recommendations to reduce the accident risk associated with maintenance of these hazardous systems are presented.

Jan 1, 1990

By Ernest A. Curth

The Bureau of Mines and Old Ben Coal Co. concluded a cost-sharing contract in 1975, the objective of which was to demonstrate the Herrin No. 6 coalbed in southern Illinois can be mined safely by longwall methods. Under the agreement, three longwall panels are to be mined at Old Ben No. 24 mine. A premining investigation laid the groundwork for specifying a roof-support system designed to control hazardous ground. Old Ben Coal Co. and Bureau engineers selected lemiscate-type roof shields. A rock mechanics program and geological mapping provide early warning capability and criteria for future equipment design. The effect of mining on the surface was monitored by a surface survey to develop subsidence-prediction criteria for the Illinois coal basin. The first of the three longwall panels started up in September 1976 and was completed in May 1977. The major adverse condition was the occurrence of limestone concretions, called coal balls, in massive pods. The shields provided adequate roof control even in faulty ground. Operation of the second panel started on August 1, 1977, following panel-to-panel transfer of the equipment. The accident rate was low.

Jan 1, 1978

By L. D. van Dyk

The extraction of iron and lead from their oxides with a volatile organic ligand such as acetylacetone in the gas phase offers potential advantages of lower energy consumption, recycling of the extractant, recovery of pure metals, and a reduced environmental impact compared with conventional extraction processes. The influence of reaction temperature, ligand flow rate, and metal oxide levels on the extraction and rates of reaction of iron and lead from single metal oxide (synthetic haematite (Fe2O3) and synthetic massicot (PbO)) systems in a fluidized bed was studied. It was found that at the investigated acetylacetone flow rates, the influence of mass transfer was limited, but that the reaction suffered from reactant starvation. When the metal load increased the effect of starvation on the rate of reaction also increased. The reaction kinetics increased with an increase in temperature for both systems. At low metal oxide concentrations more that 80 per cent of the iron and lead could be extracted from their respective metal oxides after only four hours.

Jan 1, 2012

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

By Wilbert J. Huff

The organization of the Explosives Division has been outlined in two preceding publications., The activities of the various units for the fiscal year 1939 are described hereafter: I. INFLAMMABILITY OF GASES AND VAPORS DETERMINATION OF EXPLOSION HAZARDS OF COMBUSTIBLE GASES AND VAPORS IN MINES AND INDUSTRIES (a) Determination of Limits of Inflammability of Gases and Vapors The following hitherto unpublished limits of inflammability were determined during the past fiscal year.

Jan 1, 1939