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By B. P. Simser, R. K. Brummer, A. Mortazavi, P. P. Andrieux

"A large-scale panel destress blast was fired at Brunswick mine in the fall of 1999 in order to reduce the ground stresses in a critically important neighbouring mining region. This work, sponsored by the Mining Division of CAMIRO and Brunswick mine, consisted in heavily choke-blasting — and subsequently leaving in place — a massive waste sulphide pillar in the southwest end of the 1000 m level. This paper describes the approach and design methodology used to try to maximize breakage in the rock mass in the area to destress, while minimizing damage to critical infrastructures in the vicinity. The loading operations, as well as the results of the blast — in terms of its field performances, as recorded by near-field blast vibration monitoring equipment, visual postblast assessments and measured impact on the regional stress field — are discussed as well. A brief comparison between the measured stress changes and inelastic numerical modelling of the test site is also presented.Un tir à grande échelle de relâchement des contraintes dans un pilier a été effectué à la mine Brunswick à la fin de l’automne 1999 dans le but de diminuer les contraintes de terrain dans une très importante zone de production adjascente. Ces travaux, financés par la division minière de CAMIRO et la mine Brunswick, consistaient à tirer violemment sans aucune face libre, et à laisser en place, un pilier de sulphures massifs au sud-ouest du niveau 1000 m. Cet article décrit l’approche et la démarche conceptuelle utilisées pour tenter de maximiser les fractures dans le pilier visé, tout en minimisant les dommages collatéraux à des infrastructures critiques se trouvant dans les environs immédiats. Les opérations de chargement des explosifs et les résultats du tir — en termes de ses performances, telles qu’évaluées par de l’équipement de monitoring rapproché des vibrations de tir, d’observations visuelles, et de son impact sur les contraintes de terrain locales — sont également discutés."

Jan 1, 2003

Recycling of Process Water in Sulfides Processing and Flotation Selectivity

Sep 13, 2010

By A. Himsley

"There is an ever-increasing demand these days for efficient methods of removing metals from solutions especially for selectively recovering a particular metal from a mixture of metals in solution.Up until the mid l 930's the only methods widely practiced for such separations involved precipitation techniques or electrolysis. Both these methods have limitations and indeed can only be used for certain metals.It is only within the last 40 years or so when synthetic ion exchange materials became available that chemists in industry and universities have been able to apply ion exchange techniques to a wide variety of separations that not only would be impossible by precipitation methods but which are now achieved with much greater efficiency.Ion Exchange TechniquesIon exchange is a unit process that can be applied using either liquid ion exchangers or solid resin particles. Liquid ion exchange - or solvent extraction as it is often referred to - is used in a number of special areas dictated mainly by the nature of the separation.On the other hand, ion exchange resins are much more widely used and consequently a great deal more is known about their application to a variety of metal separations.In both systems there is a loss of the ion exchange material which in the case of solvent extraction results in hydrocarbons going to waste. The ion exchange resin systems lose resin in the form of small particles, referred to as ""resin fines"", and these are insoluble.The loss of liquid ion exchanger is due to the fact that it is slightly soluble in water and consequently the loss is a function of the volume of liquid with which it comes into contact and is not related to the amount of metal processed."

Jan 1, 1975

A major problem in open pit mine planning is to determine the optimum pit limit of the mine. The optimum pit limit is the one with maximum discounted net profit and satisfies technical conditions. A number of optimisation techniques have been proposed for determination of pit limits. Among these techniques, those based on graph theory are suitable to solve the three-dimensional (3D) problem. In this paper, two maximum flow methods named, Dinic's algorithm and Push-Relabel algorithm have been used to find the optimum pit limit of an iron ore mine. This method has been implemented in Gol-e-Gohar iron mine in south east of Iran in order to find the final pit limit. Issues, like properties of the mine and orebody, are studied. These properties include wall slope, sulfur and phosphor grade restrictions. The result shows that these properties have significant effect on the determined pit limit.

Dec 6, 2010

By L. Li

The performance of microemulsified diesel and conventional diesel collectors in coal flotation was compared by flotation indicators, including combustible recovery, ash content of the clean coal, and the flotation index. An efficient separation with lower dosage was obtained using the microemulsified diesel collector. Under optimum separation conditions, the microemulsion consumption was 100 g/t less compared with diesel. The saving in diesel consumption using the microemulsion reached about 70%, disregarding the consumption of the surfactant and cosurfactant. Frothing tests showed that the frother dosage was decreased by using the microemulsion collector, because of the surfactant and cosurfactant added during preparation. The microemulsified diesel collector is superior to the conventional diesel collector in terms of diesel consumption and separation efficiency, but the selectivity requires further improvement. Keywords froth flotation, microemulsified collector, coal.

Nov 1, 2013

Flotation Performance Improvement by Air Recovery Optimisation on Roughers and Scavengers

Sep 13, 2010

By T. J. Nelson

Natural aggregates, primarily stone, sand and gravel, are recovered from widespread, naturally occurring mineral deposits and processed for use primarily in the construction industry. They are mined, crushed, sorted by size, and sold loose or in concrete products to build roads, houses, buildings and other structures. Smaller quantities are used in agriculture, cement manufacture, and chemical and metallurgical processes. The growth of cities, their buildings and the highways that connect them have created demand for enormous quantities of aggregates. Consumption has now reached 9 t (10 st) per person and continues to grow faster than population. The aggregates industry is the largest mining industry in the United States in terms of production by weight, by volume and by number of active operations. About 80 percent of the concrete pavement and more than 90 percent of the asphalt pavement is composed of aggregates.

Jan 1, 2006

Innovative and Resource-Preserving Washing Processes for Primary and Secondary Raw Materials

Sep 13, 2010

By Lloyd A. Morley

This Bureau of Mines publication presents a comprehensive review of mine electrical power-system theory and practice. It discusses fundamental theory and the vital aspects to be considered in planning and designing mine electrical power systems. The report is divided into three major sections. The first presents the history of electricity in mining and the fundamentals of electrical phenomena and components. The second focuses on power-system components: motors, grounding systems, cables, and protective equipment and devices. The final section includes mine power-center equipment, switchhouses and substations, batteries, and mine maintenance.

Jan 1, 2003

By Reginald Dias

Mining operations take a tremendous toll on equipment, operating in difficult conditions day after day. Owners and operators cannot make the job any easier, but they can give their equipment an advantage. Equipment life may be extended through preventive maintenance and the proper application of quality lubricants. This means lubricants that are made to last longer and stand up better to the punishment mining equipment must endure. There are several practices to consider as part of a successful preventive maintenance program. A good place to start is to review original equipment manufacturer recommendations about servicing and maintenance intervals for each part of the equipment, especially the engine. If these recommendations have not been followed, owners and operators must begin periodic service work on equipment to help minimize equipment down-time and extend engine life.

Jan 1, 2003

By R. E. Jones

"Crusher sizing and application in mining operations is the selection of a crusher or a series of crushers to reduce run of mine ore to a size suitable for either autogenous or conventional grinding. It is important that the crusher or crushers be sized to operate within the range to which they have been designed. By the range to which they have been designed, we mean that the reduction ration must be held between specified limits. Reduction ration is the relationship between feed size to product size.In todays plants reduction is usually accomplished in three stages by primary, secondary and tertiary crushers.Primary crushers are either jaw or gyratory and are designed to handle run of mine feed at an open side setting of 5-1/2” to 7”. Reduction ration should not exceed 7 to 1.Jaw CrushersThe model size of a jaw crusher signifies the feed opening. A model 60 x48 jaw has a feed opening 60” wide by 48” long. The 48” is the dimension between the top of the swing jaw and the top of the stationary jaw. The 60” is the width between the two side frames. The crusher open side setting is the discharge opening at the bottom of the crushing chamber with the jaws in an open position. When corrugated jaw plates are used, the open side setting is measured from tip of one jaw plate to the valley of the opposite jaw plate. If a jaw crusher has a 6” open side setting with a 1” jaw motion, you could also say it has a 5” closed side setting."

Jan 1, 1974

By M. P. Nesterov

The method of predicting the time-dependent surface subsidence for gently-inclined potash deposits where total extraction using various sizes of yielding bamier pillars was discussed.

Jan 1, 1998

By T. Skinner, M. Sahebkar

"In recent years, the mining industry has been inundated with new technologies and software systems to aid in productivity improvement. Accompanying this increased level of technology and computer systems has been the exponential growth in data sources and sinks for all aspects of a mining operation. This rapid growth in data and technology has evolved through vendor “push” approaches and user “pull” scenarios, the result of which has been that currently, no standards exist defining how data from new technology should be accessed and transferred from surface mining equipment and systems. Consequently, many incremental benefits of the systems have not been realized. This paper will present a discussion of this important issue and introduce a new committee formed to address standards to assist the industry in making effective use of current and future technology. Potential benefits accruing from the development of these standards will be illustrated through the use of a case study at Fording Coal Limited. IntroductionThe mining industry is currently faced with a rapid evolution in the computing-based systems capabilities of mobile production equipment. At the same time, there is a trend toward the introduction of even larger machines, with novel designs or incorporation of new technologies within existing designs. Computing and control technology will be required to operate and acquire knowledge about equipment operation, utilization, and performance. Such knowledge has the potential to lead to enhanced equipment design, more appropriate equipment selection, and optimized equipment performance. The equipment systems will be required to be integrated with mine production monitoring systems, maintenance management software, and a wealth of other information systems to provide a complete understanding of the effects of various factors such as maintenance, equipment design and production on economics (Roman and Daneshmend, 2001). This will lead to a better understanding and implementation of the opportunities to enhance the performance of the mine through interaction of the mine operations."

Jan 1, 2003

By Zvonimir Ester

The course of motorway tunnel under construction was set only 2 m away from the main motorway. The thickness of the tunnel overburden rock was 9 m. During the tunnel construction the traffic on the motorway was not supposed to be interrupted. The tunneling was carried out by NATM with classical drilling of blastholes and by blasting.

Jan 1, 1998

By W E. Short

Ausmelt top submerged lance technology is at the cutting edge of technological developments in non-ferrous metal smelting with commercial operations throughout the world. The Technology is being used for lead smelting, copper smelting and matte converting, fuming zinc from slags, recycling iron residue from zinc plants, processing the aluminium industry hazardous waste SPL , precious metal processing, nickel-copper residue smelting and converting, and tin smelting. The Technology is also being developed for projects involving iron-making and waste industry opportunities. There are 19 furnaces operable or under design at the time of writing. The benefits to operators using Ausmelt Technology vary depending on application, but typically result from environmental improvements, enhanced recovery of valuable products, lower capital and operating costs, more flexible operations capable of handling a wide range of feed materials, better removal of impurities, or improved product quality. Growing industry acceptance of the Technology is evidenced by the fact that more than 20 per cent of the worldÆs tin production will be extracted in systems using Ausmelt Technology when the Yunnan Tin Corporation plant starts up in 2001. Metallurgists, industrialists and investors have accepted the Technology for improved operations in both greenfield main smelters and add-on plants in Korea, China, Japan, Germany, Peru, Zimbabwe, India, Namibia and Australia. Ausmelt intends that this paper will update the industry by outlining recent achievements of the Technology in global metallurgical operations.

Jan 1, 2000

By T. Salman

Most authorities agree that the dissolution of gold from an ore takes place according to the Elsner equation first stated in 1846. The main requirements for the dissolution reaction to proceed are:(1) that the gold be clean.(2) that the gold be exposed to the solution.(3) that the cyanide solution be active, i.e., not over loaded with impurities which could retard or inhibit the reaction.(4) that an adequate supply of oxygen be available (from air).When the above conditions are met, cyanidation becomes basically a mechanical operation.Minerals such as quartz, calcium carbonate are relatively inert to cyanide though they may give rise to mechanical troubles. Most ores present an assortment of chemical problems, depending upon the constituent present, which react to the solution to varying degrees. It should be borne in mind that minerals which are disturbing to the operation, though present in small amounts, usually exceed the weight of the gold by several hundred times. In addition, the application of flotation and other forms of concentration to gold ores, previous to cyanidation, concentrates not only the gold, but also the other heavy minerals and these complicate the chemistry of the process.

Jan 1, 1975

By A. H. Larson, L. G. Twidwell

DURING the roasting of zinc sulfide concentrates and by-product recovery from flue dusts, the zinc sul-fate phase may occur in various stages of the processes. In addition to zinc sulfide, other sulfide phases are usually present such as CdS, PbS, CuzS, and FeS. Consequently, the effect of these sulfides on the thermal decomposition of ZnS04 was investigated. Merck high-purity, anhydrous zinc sulfate was used as the starting material. The sulfate was heated under an argon atmosphere, at a rate of 10°C per min. With the first slight indication of decomposition as determined by gas analysis, the sample was removed from the furnace and allowed to cool. X-ray patterns showed no other phase present. It is estimated that less than 0.05 pct of the ZnS04 decomposed. The metal sulfides were also heated under an argon atmosphere to drive off any adsorbed water. The materials were then sized (-200 to +270 mesh), mixed in predetermined mole ratios, and pressed into pellets. The experimental measurement of the reaction rate consisted of purifying the argon carrier gas, continuous flushing of the heated reacting mixture with argon, and collection and analysis of the SOn product gas. The reaction system was heated to 600°C and al-

Jan 1, 1967

By Steve Kral

In 2002, many in the mining industry — companies, academia and government — realized that the industry would soon be facing a serious shortfall in salaried and hourly employees. Depending on whose numbers are to be believed, 20 percent to 50 percent of current mining professionals are expected to retire within five to 10 years. And there are not enough students currently enrolled in mineral-related programs to the fill the need. Part of the impending shortage in professionals was brought on by the industry’s negative image, which discouraged students from enrolling in mining engineering programs. Another part was that the industry was in the doldrums and was seen by the public as a dying industry.

Jan 1, 2006

Existing processes for the recovery of platinum group metals (PGM) from UG-2 ores place stringent requirements with regard to chromite content upon feed material to the plant. An alternative hydrometallurgical process for which this is not an issue is proposed that involves reductive roasting of the ore followed by leaching with HCl/chlorine, ion exchange, and recovery of PGM from the ion exchange eluate by reduction. Problems associated with leaching of PGM are discussed and results of laboratory testwork for each of the process steps are given.

Jan 1, 2004

By Syed M. Tariq, Paul N. Worsey

Presplitting is a now a universally accepted perimeter control technique in rock excavation. The success of presplitting and the smoothness and integrity of the resulting perimeter is largely dependent on the nature of joints in any given formation. Many facets of jointing have been previously investigated. The results of the effects of joints frequency and spatial positioning were presented by the authors at the ISEE annual meeting last year. This paper includes the results of further research into the mechanism of presplit blasting being carried out at the Rock Mechanics and Explosives Research Center of the University of Missouri- Rolla.

Jan 1, 1996