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By M. L. Jeremic

"Hydraulic mining consists of coal erosion by powerful jet s of water from hydraulic monitors operated by remote control. The broken coal is crushed and mixed with water and then transported from the face to the surface using gravity whenever possible. This is a simple, safe and productive method. It will easily satisfy North American productivity standards if the structural features and coal properties are favourable for water jet cutting technology (Kaiser Resources Ltd. , hydraulic mine). General ConsiderationIn open-pit mines, placer mining (Fig. I) and hydroelectric construction projects, hydraulic earth moving techniques have been successfully applied. The stripping and transporting of the overburden has been accomplished by means of large monitor jets augmented by slurry pumps and pipes. An extension of this technique has led to the underground extraction of coal and ores. To date, the method has been most successfully used in undergrond coal mining, because the coal can be easily cut and flushed away by water jets, and the rocks of the roof strata can be left behind. Due to this favourable situation, the hydraulic mining definition only relates to the underground coal mines.At present, there are four basic types of hydraulic mining, which can be defined according to the coal breaking technique used in each case. The methods are briefly discussed below:(1) Coal excavation may be carried out by conventional techniques, but the mine is designed and equipped for the hydraulic transport of the mineral from the working place to surface. Under these circumstances, the coal breaking may not be influenced by the water jet, however it may be indirectly involved. For example, pre-loosening of the coal may be done by water infusion-hydraulic fracturing. Water may also be used to flush the broken coal, which has been excavated either by drilling and blasting or by mechanical cutting, into the transport flumes. In other cases, a mechanical loader may load the coal directly into the hydraulic transport system, without using any water for the extraction process. This hydraulic mining concept is primarily used for hard and impermeable coal, such as anthracite."

Jan 1, 1980

By Nickvinder Bhath, Johnson Matthey Plc, Jamie Baker, Daniel Kim, Jeff Lucht, Shijie Wang

"Precious metals (PM) in copper anode slimes are traditionally recovered by pyrometallurgical processes. Due to the compliance with increasingly stringent environmental regulations, it has made hydrometallurgical processing an attractive method for recovery of precious metals, including relatively inert metals such as gold and platinum group metals (PGMs). In this paper, a new method to recover PGM from complex and difficult feed streams is described. Using a proprietary Advanced Ion Exchange (AIX) adsorbent which has a high selectivity for PGMs over other metals and can achieve high PGM mass loadings with a series of incredible pilot test data plus the business case generated from the study results are also presented in the paper.INTRODUCTIONPrecious metals in copper anode slimes are traditional recovered by pyrometallurgical processes. Due to the compliance with increasingly stringent environmental regulations, it has made hydrometallurgical processing an attractive method for recovery of many metals, including relatively inert metals such as gold and platinum group metals (PGMs). Fully hydrometallurgical processes for extraction and recovery of gold and silver from copper anode slimes were employed in major copper refineries since 1995, which was first developed at Rio Tinto Kennecott Utah Copper.In Rio Tinto KUC process, the wet chlorination and gold solvent extraction were utilized to enable recovery of gold and silver as well as other metal compounds. The availability of water and the interaction and amenability of gold processing in water-based solution makes it possible that gold and silver are produced in only five days, compared with a traditional pyrometallurgical process that took 45 days. Most copper refineries are still following the tradition, but the use of hydrometallurgical technologies is increasing as the world demand for metals increases, energy utilization, and environmental viability."

Jan 1, 2016

This paper examines the latest advances in mine hoist motor and drives systems. The technology employed for large hoists has migrated from the traditional DC technology to AC motors with cyclo convertor drives, and more recently, advances in pulse width modulation (PWM) drives have resulted in these being applied to large hoist drives. When combined with PWM drive technology, the induction motor presents the ideal solution for hoist applications This paper examines the factors in choosing a suitable PWM drive and motor for a hoist installation. Factors under consideration include: ? hoist duty cycle, ? drive rating restrictions, ? choice of power semiconductor device,, ? low speed operation, ? maintenance ? reliability The cage induction motor and synchronous motor are compared and it is shown that the induction motor is the motor of choice for large hoists.

May 1, 2010

By H. K. Fredrickson

"Midwest Joint Venture (MJV) owns a high-grade uranium deposit in northern Saskatchewan. The deposit is located too deep below surface to be mined economically by open pit methods, and as a consequence, present plans are that it will be mined by underground methods. High-grade uranium ore of the type at MJV, encased in weak, highly altered ground and with radon-rich water inflows, has not before been mined by underground methods.The test mining phase of the project, completed in 1989, had three objectives: 1. to evaluate radiation protection requirements associated with the handling of large quantities of radon-rich water and mining highgrade uranium ore in an underground environment; 2. to investigate the quantity and quality of water inflows into the mine; and 3. to investigate ground conditions in and around the ore zone as an aid in determining the production mining method to be used.With information gained from the test mining project, a mining method for the production mine has been devised. Level plans have been drawn up, ventilation system designed, pumping arrangements made and methods of ore handling considered. All this is to be done in a manner that will be safe for those doing the work underground. Some of the mining methods planned are felt to be unique in that they are designed to cope with mining problems not known to have been encountered before. New problems underground have required new methods to handle them. Remote drilling, blasting, mucking and backfilling form the basis of the planned mining method."

Jan 1, 1992

By P. Cielo

"Nondestructive inspection is an important quality control tool in the material processing industry. Being nondestructive, such a control may be applied to the whole production, as long as the available techniques are fast and easily automated. Ideally, nondestructive testing (NDT) methods should operate in a noncontact configuration in order to be deployable on-line with minimum perturbation of the production process.After a short introduction to the most common NDT techniques, with particular emphasis on ultrasonic, radiographic and electromagnetic methods, a few new approaches which are under development at the Industrial Materials Research Institute, (Boucherville, Quebec), are reviewed. Noncontact techniques such as laser ultrasound, thermoelastic and thermographic methodologies will be described, and their applications to materials of industrial interest will be discussed."

Jan 1, 1989

By J. Lu, D. B. Dreisinger, G. Houlachi

"Zinc metal is primarily produced by electrowinning from sulfate solution. Zinc electrowinning is very sensitive to impurities such as Co and Ni. These impurities have to be removed to produce high-quality zinc and maintain a high zinc current efficiency. Zinc dusts are used to remove these impurities by cementation. However cobalt cementation is extremely slow and it is typically activated by the addition of Cu and Sb. Even with the use of Cu-Sb activation, cobalt is still difficult to remove. The zinc dust used for cobalt cementation is negligible compared to that consumed for hydrogen evolution. In some plants up to 6-7% of electrolytic zinc is used for cementation. This is a great waste of energy. Cu-Sb activation is not well understood. The objective of this study was to further understand the Cu-Sb activation and then find a way to reduce hydrogen evolution and promote cobalt cementation. The investigation reveals how hydrogen evolution (or zinc dissolution) and cobalt cementation and re-dissolution change with temperature, zinc dust dosage, the concentrations of copper and antimony and time. In the Cu-Sb activation, copper is deposited on a zinc particle to produce a porous shell. The zinc particle as an anode dissolves while the shell as a cathode provides a place where cobalt cementation and hydrogen evolution occur and they are catalyzed by antimony. A certain level of antimony (around 0.1 mg/L) is a key to maintain the catalytic effect of the shell. At a higher antimony concentration, cobalt cementation is accelerated slightly while hydrogen evolution is increased greatly. When a zinc particle dissolves to a certain degree, cobalt loses its cathodic protection and starts to re-dissolve. The change in cobalt concentration is determined by the rates of cobalt cementation and re-dissolution. The operation conditions can be optimized to maximize the cobalt removal and minimize the zinc dust dosage.INTRODUCTIONMost of the world’s zinc metal is produced by electrowinning from sulfate media. Many impurities such as iron, copper, cobalt and nickel are co-extracted into solution with zinc. Iron, mercury, indium, lead and tin are removed by co-precipitation as hydroxides. Copper, nickel, cobalt, aluminum, arsenic and germanium are partially co-precipitated with iron while cadmium, magnesium and chloride remain in solution. Cobalt, copper, cadmium, nickel and etc. are subsequently removed by cementation with zinc dust to achieve an acceptable current efficiency and high purity metal product for the economical production of zinc. Zinc provides a strong thermodynamic driving force for the cobalt cementation:"

Jan 1, 2016

By R. B. Kaunda

One fundamental requirement for surface and underground rock engineering is the ability to characterise the rock mass. An accurate characterisation of the rock mass allows rock engineers to optimize designs safely and economically. A number of classification systems have been developed in the past 50 years to help characterise rock masses such as RMR, Q system, Rmi, and several others. The challenge in developing rock characterisation schemes is often practicality, i.e. creating systems with relatively simple inputs for the everyday practitioner. A second challenge is the degree of subjectivity often inherent in commonly used classification systems. These challenges are especially exacerbated in weak rock or densely jointed rock masses. This paper introduces a new approach to characterise densely jointed rock mass using artificial neural networks and principal component analysis, based on principles commonly used in the geotechnical engineering of rock fills and waste rock dumps. Thirteen input parameters are dimensionally compressed using principal component analysis. Using a global database with more than 100 case histories, an artificial neural network is developed to conduct the rock mass characterisation. The advantage of this approach is less subjectivity as commonly used engineering (quantitative) terms are put to use. A further advantage is that given that the method is site-data dependent, it allows for ‘fine tuning’ of the model for a specific site.

Jan 1, 2015

By Per-Lennart Nystedt

"The Boliden Lead Kaldo Plant for the treatment of lead bearing flue-dust from the Copper Smelter and the Slag Fuming Plant has been in operation at the Ronnskar Works of Boliden Metall since the middle of 1976. At the present stage, the plant can treat lead-bearing dust of different kinds and compositions. The process allows good separation of arsenic and halogens from lead.The flue dust from the Copper Smelter and the Slag Fuming Plant is very complex and, apart from lead, also contains zinc, copper, tin, bismuth, cadmium, antimony, arsenic, sulphur, silver, chlorine and fluorine. The metallurgical process has been developed by Boliden Metall and has been tested on a pilot scale at the Foundation for Metallurgical Research (MEFOS) in Lulea, Sweden.The pelletized dust is smelted in the converter, where the heat is generated by an oil oxygen burner. The second step consists of reduction with coke. A lead bullion and slag are obtained. The slag, transported in liquid form, is treated in the Slag Fuming Plant for the recovery of zinc. The third step is the elimination of arsenic from the bullion. This is achieved by treating the lead with iron (turnings or pellets). The result is a crude lead and speiss. The lead contains silver, tin, antimony and bismuth, and is suitable for the final refining stages in normal plant equipment for refined lead.For process control, we use the rapid analysis centre, which is pneumatically and electronically linked to 'all major plant sections and allows for a quick turn-around between delivery of the sample and feedback of results. All three steps in the process are performed in the same converter.Since the starting up of the plant, the original process has been subjected to some modifications. Initial problems related to equipment, maintenance and environment have been solved step by step. Examples are quoted. Recent operating particulars are presented."

Jan 1, 1980

By Xiaoqi Sun

"Rare earth elements (REEs) have a series of specific properties making them invaluable in products including lighting, electronics and magnetism. The elements have been used in many commercial products, for example, turbines, electric vehicles, batteries, lighting, computers, cell phones and lasers. Heavy REEs are attracting the interests of scientists from many countries, and these elements have become critical to develop high-tech materials. Ion-adsorbed rare earth deposits were first discovered in China. The minerals are also called weathered crust elution-deposited rare earths. The particular types of deposits are distributed throughout southern China. The ion-adsorbed deposits are rich in medium and heavy REEs, accounting for more than 80% of the world’s total medium and heavy REEs production. However, the separation of heavy REEs from ion-adsorbed deposit is difficult owing to their similar chemical properties. The conventional separating technologies have caused serious pollution. A novel extraction strategy has been developed in this laboratory and is presented herein.INTRODUCTIONThe unique properties of rare earth elements (REEs) render them important in high-strength magnets, lighting phosphors, polishing compounds, and ceramics. Especially for applications that take advantage of the f-orbital electrons, substitutions outside the REE family are often difficult to impossible (Nassar, Du, & Graedel, 2015). Extracting and separating individual elements from mined ore is not easy, requiring lengthy operations to separate them, and this results in high costs and adverse effects on the environment. The low concentration of REE in the earth’s crust makes economic exploitation difficult (de Boer & Lammertsma, 2013) and the sustainability of the REEs separation industry has aroused considerable attention (McLellan, Corder, Golev, & Ali, 2014). To eliminate protons and break the dimmers in organic phosphonic acids or carboxylic acids, the saponification of acidic extractants by acid-base neutralization reactions are widely used in industrial REEs separation (Sun, Luo, & Dai, 2012a). The saponification procedure contributes to increased extractability and selectivity of acidic extractants to a considerable extent. The common industrial saponification mechanisms and technological processes are shown in Figure 1 and include ammonium saponification (saponified by NH3·H2O), sodium saponification (saponified by NaOH), calcium saponification (saponified by Ca(OH)2), and magnesium saponification (saponified by MgO). These inevitably result in wastewaters containing NH4 +, Na+, Ca2+ or Mg2+ because of the cation-exchange extraction mechanisms (Xiao, Long, Huang, Feng, Cui, & Wang, 2013; Song, Fu, Wang, Liu, Zhou, & Li, 2014; Sun & Waters, 2014)."

Jan 1, 2016

By Richard Lavallée

La Mine Louvicourt est une mine hautement mécanisée exploitant un gisement polymétallique avec des chantiers transversaux minés et remblayés selon une séquence primaire-secondaire. Dans certaines parties du gisement, il n'y avait qu'un accès à la coupe inférieure, car il n'était pas rentable d'avoir aussi un accès par coupe supérieure. Le minerai situé au-dessus des chantiers avec trous ascendants était considéré comme ressource non rentable par minage mécanisé. L'option de miner ces ressources avec des sous-niveaux avec accès par monterie alimak et forage long-trous de petit diamètre fût donc étudiée et démontra une rentabilité intéressante, particulièrement en considérant les tonnes ainsi minées comme tonnage supplémentaire au tonnage planifié. Dans ces chantiers, les détonateurs électroniques ont été très utiles et de plus, les coûts d'explosifs ont étés réduits considérablement par l'utilisation d'émulsion pompée en vrac.

Oct 1, 2004

By J. E. Dutrizac

A pyritic Zn-Pb-Cu ore waspercolation leached with acidified ferric sulphate solutions; zinc and copper were leached, lead was oxidized, but not dissolved, and pyrtte was essentially unattacked. High zinc extractions were achieved after a few months leaching, and substantial zinc solution concentrations could be produced by recycle of the oxidized solution. The leaching rate was generally controlled by the transport of the ferric sulphate oxidant. Zinc extractions increased with increasingferric ion concentration or flow rate, but were essentially independent of the concentrations of sulphuric acid, ferrous sulphate, cupric sulphate or chloride ion. The leaching rates were insensitive to the height of the ore column once a minimum height had been exceeded (0.8-1.0 m). Elemental sulphur was the principal sulphidic reaction product, but variations in the ratio of sulphur to sulphate produced anomalous temperature effects.

Jan 1, 1979

By A. McIntyre, L. R. Plitt

Both the Bond and the Hardgrove grindability tests are widely used in the mineral industry to measure the ease of the comminution displayed by a material. The Hardgrove test is mainly used for coals, whereas the Bond grindabifity test is mainly applied to hardrock minerals. The Bond grindability has the advantage that it can be empirically related to the energy required for comminution (work index), whereas the Hardgrove grindabifity test has the advantage of being easier to perform. In an effort to establish a valid correlation between work index and Hardgrove grindability, a series of parallel grindability tests were carried out on a wide variety of rocks and minerals. The standard Hardgrove test was modified to allow for materials with a higher density than coal. A new, satisfactory relationship was established which permits rapid estimation of work index from Hardgrove test data.

Jan 1, 1980

By R. G. L. McCready, Marco Zentilli

"Brogan coal containing mean averages of 6,93% w/w total sulphur (1.1% sulphate sulphur, 1.6% organic sulphur and 4.24% pyritic sulphur) and 16.34% mineral ash was used as the test coal in these studies.Shake-culture leaching studies on seven size fractions of the coal, ranging in size from 0.045 mm to 1.7 mm, showed that the rate of pyrite leaching was inversely proportional to the particle size. As the use of continuous stirred tank reactors would be uneconomical for the reclamation of waste coal, column leaching studies were initiated on coal sieved to >6.35 mm to < 12.7 mm, The leachate was monitored for all metal ions and the release of iron was used to monitor the rate of pyrite oxidation . Measurable amounts of Zn, Co, Ni, Mn, and V, all of which can replace iron in the pyrite crystal structure, were released during the initial stages of leaching. Further, high concentrations of AI, Ca and Sr and trace amounts of Sn, As. Se, B, Ca, Cr, Si, and Ti were detected in the column effluents.These studies suggest that bacterial leaching will remove the pyrite and qualitative amounts of environmentally undesirable trace metals from the coal if such a process is developed for waste coal reclamation.IntroductionIn 1947, Colmer and Hinkle showed that acid mine drainage was the result of an oxidative attack of the iron-mineral sulphides by Thiobacillus ferrooxidans to produce sulphuric acid . Ashmead (1955) proposed the use of these organisms to desulphurize coal , but the subsequent research effort was concentrated on the metabolism and physiology of these extreme acidophiles.A limited number of studies have been reported on the bacterial leaching of pyrite from coal (Silverman et al., 1963; Dugan, 1977). However, the bacterial oxidation of pyrite is a self-limiting first-order reaction, probably due to the precipitation of Fe(OH)J and elemental sulphur , which progressively inhibits intimate contact between the bacterial cells and the sulphide-mineral surface. Consequently, the best pyrite oxidation experiments with coal reported to date required five days to remove 97070 of the pyrite (Dugan &Apel , 1978) using mixed cultures of T. ferrooxidans and T. thiooxidans."

Jan 1, 1985

By K. M. Sarkar

"In many plant trial s(1,2) it has been proven that very small amounts (10 to 20 ppm) of uranium dissolved in mine water can be effectively recovered by the use of ion exchange resins and this uranium recovery has many advantages. In this paper an economic analysis at different levels of uranium contamination and at different market prices of uranium are described.For this study an operating mine-mill complex with a sulphuric acid leach circuit, followed by solvent extraction (SX) process, is considered, where contaminated mine water is available in excess of process requirements. lt is further assumed that the sulphuric acid eluant containing uranium would be mixed with the mill pregnant liquor stream that proceeds to the SX plant for final uranium recovery.Recovery by Ion ExchangeMine water, in this study, is defined as the water coming from the underground mine, or mine pits, and the run-off water from stockpiles, mine shops, crushing plant , washdown areas, etc.In nature, uranium mainly occurs in two stages; reduced (tetravalent) and oxidized (hexavalent) . The oxidation of sulphides present in the orebody often causes the presence of S04- and acidity in mine water, and this acidic water readily dissolves U+6 part of the depo sit. The react ion between hexavalent uranium, which is dissolved in water as U02+ 2 cation and S04 producing uranyl sulph ate as,"

Jan 1, 1984

By H. W. Smith, D. Guerin

"This paper describes the development of a dynamic model for a full- scale (64 tonnes/hr) grinding circuit consisting of an open-circuit rod mill feeding a ball mill operating in closed circuit. The object of constructing such a model is to investigate the static and dynamic behaviour of potential control schemes. Model selection, data processing and parameter estimation are discussed, and static and dynamic results of simulations are presented. Conclusions are drawn with regard to the adequacy of the model for such studies, and likely limitations on control of such circuits.IntroductionThe model developed here is intended to represent the grinding behaviour of the grinding circuit at the Lake Dufault division of Falconbridge Copper Mines Ltd. This circuit has been fully described elsewhere. At the time of the work described, the ball mill discharge was fed to a four-cell flotation bank , the tailings of which are combined with the rod mill discharge in the cyclone feed pump sump. As the emphasis in this study is on grinding behaviour, and as only I per cent of cyclone feed material is removed in these cells, no attempt has been made to include flotation behaviour in the simulation. One effect of the presence of flotation cells in the grinding circuit is, however, to necessitate somewhat finer grinding than might otherwise be needed: this will have effects on mill parameters.The paper is organized as follows. First the selection of models is discussed, paying particular attention to the problem of selecting simple, yet adequate, flow models for the mills. Then data gathering is described. The method of deriving mill model parameters is explained, and the results presented. Mass balancing of cyclone data and the determination of cyclone model parameters are described. The linking of the models into a full simulation is outlined, and sta tic and dynamic results presented. Finally, the results are discussed and conclusions drawn ."

Jan 1, 1980

By Marc C. Bétoumay

Workplace safety, health, climatic conditions and rising oil prices are aspects that are important to the mining industry. The need for cleaner energy for underground mine vehicles is requiring serious consideration. A number of alternate energy systems offer clean solutions to diesel emissions while maintaining the current liberty of vehicle movement. This watershed article provides a broad comparison of cleaner diesel and alternative energies for underground production vehicles. Most alternate energies and clean diesel have already been tested in underground production vehicles. There are no technology gaps that would prevent the development of commercial alternative energy power plants, but in the case of alternate energies, second and third generation versions will be required to fully test for safety and operation viability. Full regulatory development is also required and could be done in parallel to power plant testing. Vehicle operation and maintenance manpower would be the same for alternate energy application as for clean diesel. Capital cost for alternate energy power plants will remain higher until the medium term. Owing to significant ventilation savings possible with alternate technologies, operating costs would be reduced.

May 1, 2011

By H. M. Giegerich

"INTRODUCTIONThe Red Dog Project in Alaska is being developed by Cominco Alaska, a subsidiary of Corninco Ltd. of Canada, and the Nana Regional Corporation, one of the 12 native corporations created by the Alaska Native Claims Settlement Act of1971.The State of Alaska is also a very key part of the project through its financing of the transportation system for Red Dog. Red Dog will be the third, and largest, of Cominco&apos;s Arctic mining developments in the past thirteen years, after the Black Angel Mine in Greenland, which started up in 1973, and the Polaris Mine in the Canadian Arctic, which began production six years ago in 1982.Red Dog is one of the world&apos;s great mineral deposits, with a unique combination of large size, high-grade, and a waste-to- ore ratio less than I: I, which will make it the world&apos;s largest, and one of the lowest cost zinc producers, when at full production. The present mineral reserve is estimated to be 85 million tons , at a grade of 17.1010 zinc, 5% lead, and 2.4 ounces per ton of silver. Based on the current production forecast, this will give a mine life of almost 50 years, and the deposit is still open in two directions, although the structure is becoming thinner at depth. As well, there is a satellite zone about one mile south of the main deposit which could contain up to another 8 million tons of mineral at Red Dog grades or better. This is not presently included in the reserve due to potential processing difficulties.In relation to other zinc deposits, Red Dog is the second largest ever discovered, smaller than the original Broken Hill deposit in Australia, but larger than Cominco&apos;s own Sullivan Mine in British Columbia, which is number three. It is quite possible that, when the area is adequately explored, Red Dog will be number one."

Jan 1, 1989

By J. E. Zajic, E. A. Sullivan, T. R. Jack

"The release of vanadium, iron, nickel and titanium from the cokes produced in the upgrading of Alberta oil sands bitumen has been assessed for simple chemical leaching processes. Flexicoker coke (Exxon Engineering and Research) has been found to be quite amenable to the recovery of vanadium as well as nickel, iron and some titanium by these techniques, whereas fluid coker coke (Syncrude) and delayed coker coke (Great Canadian Oil Sands) are relatively intractable under the mild conditions employed. The factors affecting the extent of vanadium release are discussed in terms of the surface area accessible, the wettability of the material, and the chemical and physical composition of the coke particles in each case.A novel biologically assisted heap leaching procedure for f1exicoker coke is also described, based on the growth of the chemolithotrophic bacteria, Thiobacillus thiooxidans A TCC 8085, on elemental sulphur added to the coke."

Jan 1, 1980

By Bong Sun You

AZ31 magnesium plate of 300mm in width and 40mm in thickness was produced by horizontal continuous casting machine, and its microstructures were analyzed on the surface and in the plate interior. The defect formation on the surface and subsurface, such as side cracks, buckling, pores and segregation, was very sensitive to the casting condition and processing parameters. Especially, casting speed and secondary cooling were the most dominant parameters to control the solidification behavior of magnesium melt, for example the position and shape of the solid/liquid interface in the mould. The cyclic marks on the surface were obvious because the plate were drawn by 4-step cycle and can not be removed. The average grain size of as cast plate measured as 50-65µm at the near surface and 300-400µm in the center of the plate was relatively small because secondary cooling water was applied to control the surface quality resulting in rapid solidification of the melt in the mould.

Jan 1, 2006

"The Society for Mining, Metallurgy, and Exploration (SME) Inc. developed a guide of minimum standards for reporting exploration results, mineral resources, and mineral reserves for the purpose of informing the general public. The SME Guide has been adopted by the Society.History1. In 1988, at the request of members of the Society for Mining, Metallurgy, and Exploration (SME), Inc., the President of SME formed Working Party #79, Ore Reserve Definition, with the mission to develop guidelines for the public reporting of exploration results, resources, and reserves. A Subcommittee was appointed by the Working Party to draft these guidelines and submit recommendations to SME. The Subcommittee's recommendations were published by SME in the April 1991 issue of ""Mining Engineering"", and as a document entitled ""A Guide for Reporting Exploration Information, Resources, and Reserves"" (the SME Guide) in January 1992. Work continued on an ad-hoc basis until 1996, when Working Party #79 was renamed the SME Resources and Reserves Committee and became a standing committee.In 1994, the Council of Mining and Metallurgical Institutions (CMMI) started a concerted international effort to create a set of international definitions for reporting mineral resources and mineral reserves. An ad-hoc International Definitions Group was formed, with representatives from mining and metallurgical institutions from the United States (SME), Australia (AusIMM), Canada (CIM), the United Kingdom (IMM) and South Africa (SAIMM). A major breakthrough came on October 18, 1997 when the CMMI International Definitions Group met in Denver, Colorado and reached a provisional agreement (the Denver Accord) on definitions of mineral resources and mineral reserves. Concurrently, and since 1992, the United Nations Economic Commission for Europe (UN-ECE) was developing an international framework classification for mineral resources and mineral reserves. Starting in October 1998, joint meetings were held in Geneva between the CMMI International Definitions Group and the UN-ECE Task Force, resulting in agreement to incorporate the CMMI definitions into the UN framework classification."

Jan 1, 2003