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By P. Pal Roy, R. B. Singh

"This paper focuses on a number of interesting results to establish the theory and principle of air-deck blasting. It also gives the mechanism of breakage that takes place in air-deck blasting under varying charge load conditions. With these aspects in mind, the mine management can implement this up-coming technology to enhance safety and higher productivity. IntroductionThe method of air-decking has become an increasingly popular technique in production and presplit blasting. In the blasthole, an explosive column is combined with an airchamber. The main aim of the technique is to control breakage through effective distribution of explosive energy and thereby enhance uniform rock fragmentation. An air column lowers the initial pressure of the explosive products and simultaneously increases the time of interaction for the detonation front with the surrounding rock, which enhances rock breakage.To study air-deck blasting, CMRI initially conducted experiments using indigenously developed, low-cost wooden spacers of different sizes and strengths. Air-deck blasting was first tried using these spacers in 1993 at Jambad OCP, ECL and Chasnalla OCP, IISCO. The experiments were extended in 1994 at Bermo Mine, DVC. The results were subsequently published by Pal Roy et al., in 1995. It is worth mentioning that the performance of air-deck blasting during this period was only compared with conventional blasting practices without going into detail of the theory behind the process."

Jan 1, 2001

By Anton Gronningsater

MR. J. R. GORDON: The authors are to be congratulated for their excellent papers on Copper-Nickel Matte Converting. Mr. Drummond's paper contains the results of a thorough and exhaustive study of a series of converter charges. Mr. Gronningsater has presented convincing arguments in favour of his claim that the converter has been neglected as a smelting machine for ore. Some of us may not be inclined to agree with his conclusions. Converting, like most metallurgical operations, is a compromise between an ideal and a practical operation. If it were possible for one to neglect entirely the matter of converter linings, I believe we would all agree that the proper flux for matte in a converter would be pure quartz. Under such ideal conditions, one would, if proper temperature were maintained, make the smallest quantity of slag containing a minimum of magnetite. Converter slags are notorious for their high metal content and must always be subjected to a further cleaning treatment before being discarded. For that reason, the tonnage of converter slag produced should be minimized. If norite is used as a converter flux, then the tonnage of converter slag would be greatly increased if the silica content is maintained at 27 per cent or higher. I cannot agree with Mr. Gronningsater's suggestion that, in con¬sidering a converter flux, the sum of the silica, alumina, alkaline-earths, and alkalis should be considered as being of value. The alkalis and alkaline-earth contents of the flux will replace iron in the silicates formed and tend to increase the viscosity of the slags. However, if the converter is to be used as a smelting machine, it will be necessary to drop the silica content of the converter slag in order to avoid production of excessive slag tonnages.

Jan 1, 1942

By Simon B. Blancher, Malo Rousseau, Renato Contessotto, Thomas Wallmach

The Manganese division of the ERAMET group extracts manganese ore in Gabon and produces manganese alloys for the steel industry. ERAMET has an economic interest to maximize the ore throughput without reducing the lifetime of its manganese mines. This can be achieved by means of research and development leading to innovative ore beneficiation processes. For this purpose, the ERAMET research center has designed and constructed a new pilot plant for ore beneficiation by physical separation processes. This pilot facility was erected within an infrastructural and synergetic framework, including competencies in hydrometallurgy, pyrometallurgy, numerical modelling, analyses and mineral characterization that provide ideal research conditions. After laboratory scale tests, a pilot operation of beneficiation of low grade Mn ore (around 35% Mn) was carried out by jigging of the 1-10 mm fraction. This gravity separation process exploits density differences between the various Mn-bearing minerals such as pyrolusite and lithiophorite as well as gangue minerals such as silicates and iron-hydroxides. Enrichment leads to the production of a marketable product associated with a high mass recovery (53% for the jigging step). However, 20% of pyrolusite and 30% of lithiophorite are lost in the waste. Mineral characterization has shown microtextural complexities, but grinding the ore to approach the liberation mesh was not an option due to commercially defined constraints given by the ferro-alloy industry. Recovery of the Mn-bearing minerals or adjustments of the feed grain size (6.3-10 mm) are two potential areas of process improvements identified by means of Qemscan® mineral characterization. This paper details the process tested on a pilot scale (0.5 t/h), which has led to a significant increase in the beneficiation of a low grade Mn ore.

Jan 1, 2016

By W. K. A. Congreve

Introduction Less than a hundred years ago the engineer was able to do his job without concern for the science that underlay his practices or for the men who operated his machines. But toward the end of the last century science began to be applied to industry, and its success was such that the plant which clung to empiricism was unable to compete with the plant that followed science. Even more recently, the engineer has been forced to consider the men who operate his machines, for modern large-scale industry has given these men education, social security, and power. Hence the engineer can get good, steady labour to operate his machines only if he can offer inducements. Wages are in general outside the control of the engineer, but he is able to control working conditions. This essay is concerned with one factor of good working conditions: safety. The writer became interested in this problem during three months' summer employment as a student at the Sullivan concentrator of the Consolidated Mining and Smelting Company and was surprised at the distance his investigations led him from the field of pure engineering into the fields of psychology, education, and publicity. Nevertheless, because safety has to do with machines and with men who operate machines, and because it profoundly affects plant efficiency, it is the job of an engineer, not of a psychologist or teacher, nor of the salesman publicity expert who is often so unfortunately employed in personnel relations. The size and complexity of the subject has limited the scope of this essay to the consideration of only a few aspects of industrial safety. Considerable attention has been given to the underlying principles, but the mechanical side of accident prevention, the design of equipment, erection of guards, etc., and the very important problems of organization and administration, have not been given attention proportionate to their importance.

Jan 1, 1948

By Robert B. Parsons

"Starting January 1, 1987 employers, employees, and other taxpayers are confronted with a new set of rules dealing with the taxation of travel and housing benefits relating to isolated posts in Canada, and tax deductions relating thereto. The new rules may not be the simplest in the world, but they are reasonably fair and at least offer a hitherto unknown degree of certainty as to how such allowances are to be treated. IntroductionThe first shoe fell on February 26, 1986 when Finance Minister Michael Wilson' s first budget presented the framework for the future tax treatment of travel and housing benefits (so-called ""northern allowances"") provided to residents in remote regions of Canada. The second shoe fell some ten months later on December 22, 1986 when the Minister of Finance filled in the earlier announced framework with detailed rules. We now have a complete picture of the tax treatment of northern allowances. Here is what the picture looks like with effect from January 1, 1987.According to Revenue Canada, the net housing benefit to employees will be equal to the value of the accommodation provided, less any rent they have paid. In major centres such as Yellowknife and Whitehorse, having a developed rental housing market, the benefit amount will be based on the fair market value of the rental accommodation in that location. In other areas, employers will be required to value the housing benefits and, to assist employers, Revenue Canada has provided the following guidelines: Common shelter- $100 per month including the value of subsidized utilities Apartment! duplex-$270 per month excluding the value of subsidized utilities, or $400 per month including the value of subsidized utilities House-$450 per month excluding the value of subsidized utilities, or $650 per month in- c1uding the value of subsidized utilities.The amounts established as the values of accommodation will be adjusted annually after 1987 based on the housing component of the Consumer Price Index."

Jan 1, 1987

By S. Luidold, A. Poscher, H. Antrekowitsch

"The rare earth elements (REE) are nowadays mainly used for permanent magnets, catalysts, hydrogen storage alloys in rechargeable batteries, for glasses, ceramics, and polishing agents. Other important areas of application are phosphors in different types of lamps (fluorescent tubes, energy-saving lamps, etc.). These lamps are often collected and treated at their end of life by disintegration and sorting. However, the obtained fine fractions comprise not only REE-containing phosphors but also small amounts of mercury and are therefore disposed till today in special landfills. Due to the enormous price increase of the rare earths during the last two years, a lot of activities started for extracting these elements from secondary resources such as for example phosphors. All recycling concepts for this task mainly work with hydrometallurgical methods. The large number of different compounds in phosphors with sometimes very different behaviors with respect to their solubility in aqueous phases forms a major challenge to achieve good yields as well as acceptable purities of the produced rare earth concentrates by a process with a reasonable number of operation steps. Therefore, this paper gives at first a brief overview about the compounds, used as phosphors and about existing concepts or investigations. It further describes our own process design and the results, obtained on laboratory scale. INTRODUCTIONThe rare earth elements (REE) have a central position in the industrialised world despite their marginal production volume in comparison to common metals such as aluminium, copper, zinc etc., because they are essential for many applications. They often cannot be substituted without a considerable loss on functionality and quality. This group of metals comprise the lanthanoids (f–block elements, lanthanum–lutetium) as well as scandium and yttrium.The estimated world mine production of REE amounted to 133,000 t rare earth oxide equivalent in 2010, whereat China accounted for 130,000 t or 98 % (Cordier, 2012). The European Union (EU-27) imported 23,013 t in 2008 to cover its demand. The figure 1 shows the fraction of the European member states in terms of the total imports of rare earth compounds from outside the EU-27 (Schüler, Buchert, Liu, Dittrich, & Merz, 2011)."

Jan 1, 2012

By V. Itkin

"Three methods were tested for the beneficiation of aluminum scrap, generated by heavy medium separation of non-ferrous automobile scrap residue. These were: crushing in a shredder followed by screening; grinding in a ball miff followed by screening; and eddy current separation. The best results were obtained with the grinding-screening method. IntroductionThe usual method of aluminum alloy reclamation from non-ferrous automobile scrap residue consists of a two-step heavy medium separation to remove materials lighter than and heavier than aluminum. The resulting aluminum scrap still contains over 15% impurities such as stones and glass, heavy rubber, insulated copper wire , plastics and heavy metals entrapped by macerated aluminum piece s, composite fragments, etc.(2). Upon melting, these impurities create difficulties and yield a low ingot recovery-65% to 70%, hence small foundries avoid this material.There are a number of ways to improve the quality of aluminum scrap such as:(1 ) crushing of the scrap, which powders the brittle content , a major impurity component, followed by screening out of the dust(2) eddy current separation , which removes metals from the material flow, and(3) implement better methods for density separation.The eddy current separation and two variants of the comminution-screening technique were studied by Intermetco Ltd., Hamilton , Ontario."

Jan 1, 1986

By Kevin B. Doyle

"Canada now supplies 23 per cent of the world demand for potash. Although potash is produced by many countries, Russia and Canada have the greatest reserves and capability to supply the future substantial demand over the next decade. It is estimated that demand will grow from 38,000,000 mt KCl in 1975-76 to 60,000,000 mt KCl in 1985-86. Current firm expansion plans and development underway in the world will move Russia to the forefront in supplying this demand growth. Russia will move from supplying 40 per cent of world demand in 1975 to supplying as much as 52 per cent in 1981. Canadian deposits suffer from natural disadvantages, such as high costs and risks of mine development and operation, and high-cost transportation to international markets, but experience has shown that these natural barriers can be surmounted to effectively compete in these international markets. However, Canadian potash is losing out in the race to supply the growth in the world potash demand over the next ten years because of artificial barriers raised through the unhealthy environment created by the current battle between different levels of government and the industry over resource taxation and legislation."

Jan 1, 1976

By J. J. Gillman

"The coal deposits from Cape Perce on Cape Breton Island have been known to supply the coal requirements of the people living in or visiting the area for close to 300 years.A major block of coal has been identified off Cape Perce, which has several seams from which coal can be taken. The initial development by the Cape Breton Development Corporation will be in the Harbour Seam and constitutes the Donkin-Morien Development Project.The CBDC's confidence in this indicated resource is based on its knowledge of the Sydney Coal Field and from boreholes driven into the block during the summers of1977, 78 and 79. In 1980, further geological data were gathered from surface drilling and an intermediate-depth high-resolution seismic survey. The surface facilities for the Donkin-Morien Development Project will be located on the northern half of the cape, with access declines extending 3.9 km in a north-northeasterly direction to the Donkin block of coal reserves. The development has the potential of supplying all the coal needed f or the future electrical power generation requirements of Nova Scotia for many years to come.The planned mine, for which a project definition study has recently been completed, will have a production rate in excess of 3 million tonnes per year.IntroductionAt the Second CIM District 1 Meeting held in Halifax in October 1980, a background paper on Phase II of the Donkin-Morien Development Project was presented. The project involves a 3.2-million-tonne, saleable, underground coal mine. At that time, the chronological sequence of events had unfolded, starting with the initial boreholes through to the feasibility study, and on through site clearing and site preparation. This led to engineering design contracts for the portals and the two tunnels to be driven to intersect with the Harbour Seam close to 4 km from their entry point."

Jan 1, 1982

By T. A. Wheat

"The presently increasing world-wide interest in advanced ceramic materials is generally focussed on their exploitation in both structural and functional applications. With the opportunity to engineer microstructures and thereby closely control and tailor the final properties, there are many new applications being made for these materials in both areas.The scope and some of the applications for functional ceramics are reviewed and examples of the present Canadian activity in this field are discussed.BackgroundThere has been progressively increasing international interest in the development and exploitation of ceramic materials in the last five years. The stimulus for this interest arises from several quarters, each of which are independent of the other.• There is a growing awareness of the strategic nature and vulnerability of supply of the raw materials used to produce high performance metal alloys.• The metal alloys are reaching the upper temperature limit for their performance as structural components in engines.• The dramatic increase in oil prices during the late 1970s focussed attention on the need for reduced consumption in many sectors, i.e., there is a need for more efficient engines that operate at higher temperatures - above those tolerated by the present superalloys.• A number of ceramics, especially the structural materials such as SiC, A120 3, AI20rSi02, Si3N4 and the Sialons are produced using non-strategic raw materials and they can exhibit startling performance-auto turbo-rotors are in production mad e of Si3N4 that operate up to 190000 rpm at 600°C, 150000 rpm at 900°C.• Ceramic s are generally of lower density - significant in the weight-reduction of automobiles such as the replacement of a 20-kg five-segment steel leaf spring with a single segment carbon-fibre reinforced unit of 3 kg. • Ceramics also offer major ad vantages in generating, monitoring or controlling the electromagnetic spectrum whether in bulk or thin-film devices that exploit optical, magnetic, pyroelectric, piezoelectric, electronic and I or ionic conductivity characteristics.The opportunity to combine several of these char acteristics in a single material by composition, processing and microstructural design has resulted in an advanced ceramics industry that had world-wide sales in 1980of $4.2 billion (U.S.)(I) and is predicted to grow to sales in the range $7 to $10 billion by 1990 and $16 to $24 billion by the year 2000(2). However, at present, advanced ceramics account for less than 20010 of the total ceramic market."

Jan 1, 1987

By G. M. Ritcey, S. H. Lucas

"On the north shore of the St. Lawrence River, in Quebec, are located orebodies of low-grade titaniferous magnetite. The Quebec Mining Exploration Company (SOQUEM), who have an interest in the deposits, believed that beneficiation of the could generate sufficient revenue to defray the mining costs and the costs of transporting the ore to a steel production facility. A joint research project of SOQUEM and CANMET investigated alkaline roasting of a magnetic concentrate, followed by leaching of the calcine and separation and recovery of Cr and V by solvent extraction. Aluminum was recovered by precipitation.The present paper describes the roast-leach bench-scale and pilot-plant work leading to the development of the optimum conditions f or the integrated process.A plant flowsheet was developed for the treatment of 5 x 106 tons of magnetic concentrate per annum. Estimates of capital and operating costs were made.Based on a recovery of approximately 90% V, 85% Cr and 75% AI, the total hydrometallurgical plant fixed capital costs, including mining, concentration and shipping, are estimated at $1.021 x 109; the operating costs are estimated at $131.92/ton concentrate. Annual revenue from the Na2CrO4.H2O, V2O5 and A12O3 produced is calculated to be $421 x 106.IntroductionThe Quebec Mining Exploration Company (SOQUEM) acquired in 1968 an interest in four titaniferous magnetite orebodies located in Eastern Quebec. 85 miles north of Mingan on the north shore of the St. Lawrence River. The Mingan deposit, with an estimated tonnage of one billion tons, has a reported average grade of 43% Fe, 6.3% Ti , 1.60% Cr, 0.19% V and 6.1% Al with minor amounts of nickel. SOQUEM, on the basis of previous bench-scale data, believed that the recovery of chromium, vanadium and alumina by alkaline roasting would generate sufficient revenue to defray the mining costs and the costs of transporting the ore to a steel production facility on the coast. One of the approaches selected by SOQUEM for beneficiation of the ore consisted of a combination of magnetic concentration followed by alkaline roasting of the calcine."

Jan 1, 1980

By Robert B. Parsons

"While it might seem like heresy to suggest that ""taxation"" can be a source of financing, never the less some generous tax rules can considerably enhance the tax savings pertaining to a particular expenditure or project. A basic tax knowledge, and careful tax planning, can optimize government participation in a project. INTRODUCTIONIn trying to identify sources of financing for a project, ""government"" as a source of funding is normally thought of in terms of government grants, loan guarantees, interest rate buy downs, property tax waivers, hydro subsidies, and so on. Generally, such concessions are somewhat difficult to obtain, especially in the current period of apparent fiscal restraint. One source of government funding which should not be overlooked is the income tax regime, and, at the provincial level, the various provincial mining tax regimes.While the taxpayer would not normally view a tax system as a potential source of government financing, nevertheless various federal and provincial rules applicable to the mining industry can offer attractive tax deductions - and tax savings - with respect to particular expenditures. In fact, it is not unusual for a civil servant to refer to a tax deduction as a tax ""subsidy"". For example, in the right circumstances, the cost of a smelter expansion in New Brunswick would cost the operator only 31 cents on the dollar, with the federal and provincial governments paying for the other 69 cents by foregoing tax revenues (Table I). In a sense, such tax savings could be compared to a government grant equal to 69% of project costs. Of course, not every project expenditure will generate that degree of government funding. The fact of the matter is that the percentages of tax savings attached to different expenditures cover a wide range, depending on a complex mix of factors. The point to understand is that the tax rules can offer some valuable savings, even after tax reform, and that a basic knowledge of the tax rules can yield some fruitful rewards."

Jan 1, 1989

By J. M. Skeaff

"The main solution, ore and residue pulp streams in the Rio Algom Quirke I uranium mill at Elliot Lake have been sampled and analyzed for radium-226. Analysis of the ore and leached residues indicates that Ra-226 dissolves and precipitates within the first pachuca tank. A maximum of approximately 0.2% of the Ra-226 in the ore remains in solution during leaching.IntroductionConcern over the acid drainage and radionuclide dissolution problems associated with uranium tailings disposal sites in Canada has prompted investigation into methods for improving current uranium processing practice.Present commercial practice usually involves leaching of the uranium ore with sulphuric acid, ion-exchange separation of the uranyl sulphate complex from the leach liquor and"" precipitation of the uranium as yellowcake. Daughter products of U-238, such as Th-230, Pb-21O and Ra-226 remain with the tailings and undergo long-term dissolution.Table I summarizes the probable behaviour of the radionuclides during milling. The concern here is with Ra-226, because it will deposit in the bones if ingested and is ""thus considered a serious health hazard(1), Similarly, Po-218 and Bi-214, which are daughter products of Rn-222, can be retained in the lungs and are considered to be the principal sources of radiation dosage(2) arising from the inhalation of Rn-222. Previous investigations(3-9l indicate or imply that Ra-226 undergoes redistribution during milling. However, detailed published information on the behaviour of Ra-226 in the uranium milling process appears to be lacking. A knowledge of the behaviour of Ra-226 in uranium mills, particularly during leaching, could lead to improved methods for its control.This paper reports the occurrence of Ra-226 in the Rio Algom mill. The main objectives of the study were to determine (1) the distribution of Ra-226 within the solids, (2) at what point, and how rapidly, redistribution occurs and (3) whether there are high concentrations of Ra-226 in solution."

Jan 1, 1981

By Y. Héroux, A. Chagnon, M. M. Savard

"Résumé- Le gîte de Pb-Zn de Gays River s'accompagne d'anomalies des propriétés de la matière organique (MO) et des assemblages de minéraux d'argile (AMA). L'association entre la minéralisation, la distribution de la réflectance de la MO et des AMA suggère que ces traceurs peuvent servir à l'exploration des sulfures de métaux de base dans cette région.A l'emplacement du gîte, la réflectance varie considérablement (0,80% à 1,88%), pouvant même afficher une baisse avec l'enfouissement, ce qui est interprété comme une altération chimique de la MO. Les valeurs les plus élevées s'accompagnent localement de quelques textures en mosaïque et délimitent une anomalie thermique au centre sud de la région. Parmi les minéraux des argiles identifiés, l'illite et la chlorite sont terrigènes alors que la smectite, la kaolinite et la corrensite sont authigènes et, à l'instar de l'altération de la MO, résultent des nouveaux équilibres chimiques créés suite à la précipitation des sulfures.Abstract- The Gays River Pb-Zn ore deposit is associated with anomalies defined from the characters of the organic matter (OM) and from the clay minerals assemblages. The relationships be­ tween these anomalies and the mineralization at the mine suggest that these parameters can be used as new guides for the exploration for base-metal sulfides in this area.The vitrinite reflectance (RJ shows a wide range of values (0.8% to 1.88%) and exhibits an anomalous suppressive effect with depth of burial at the mine site, suggesting a chemical alteration of the OM. The highest R, values are associated with mosaic textures and outline a thermal anomaly at the south-center of the studied area. Among the identified clay minerals, illite and chlorite are terrigenous, whereas smectite, kaolinite and corrensite are authigenous and, like the alteration of the OM, are due to the new chemical equilibria resulting from the precipitation of the sulfides."

Jan 1, 1994

By Peter Clevenstine

Minnesota Iron Ore Trifecta 1. World Demand 2. Industry Consolidation 3. Competitive Advantages

May 1, 2011

By Xue Yang

Even though many approaches have been proposed for automated fault detection and diagnosis of Heating Ventilation and Air Conditioning (HVAC) systems, and advanced maintenance programs, such as preventive and predictive maintenance have been applied for the systems, issuing work orders for corrective maintenance is still a reality. Currently corrective maintenance still accounts for more than 55% of all maintenance programs in average facilities in the US (DoE, 2010). Indoor air related problems are especially important among corrective maintenance work orders. This paper provides details of a case study conducted to capture the workflow that HVAC mechanics follow, their rationale in diagnosis process and the information they typically refer to while responding to indoor air related corrective maintenance work orders. The general workflow for HVAC mechanics to complete such types of work orders was summarized into 5 stages, and generic information requirements recorded from the case study were synthesized. Initial findings show two main challenges in the industry for HVAC mechanics to get access to required information, which highlights the need for a systematic approach that would enable identification of such information applicable to a given context under which a work order has been generated and provide values of required information for HVAC mechanics to do sound diagnosis through integrated data repositories.

Aug 1, 2013

By Normand Champigny

The Forces of Change ? The current business environment ? What can we expect for the future on management of physical assets ? The impact of maintenance on production costs ? What is RCM is doing is improving business performance ? The beginnings of RCM The RCM II Process ? RCM II is a structured process that involves employees in determining the best failure management tactics for systems and equipment in their operating context ? The method is an effective approach to risk and cost reduction as well as failure management

May 1, 2002

By William E. Stanley

The paper examines the problems that arise in undertaking socio-economic impact studies to meet the requirements of environmental-impact legislation governing new mine development or expansion. An approach to undertaking socioeconomic impact studies is outlined, responses to specific problems are discussed and ways in which the mining company can use these studies to meet its general objectives are explored. The paper concludes by examining how a socio-economic study, as required by legislation, can be used to assist the mining company in achieving some general objectives it will have in developing a mine.

Jan 1, 1979

By R. J. Mitchell

"Centrifuge modelling of earth structures is a well-proven technique for evaluating the performance of prototype structures using physical models. The applications of this technique have increased dramatically during the last decade such that even the modelling of dynamic responses in structures has been accomplished.This paper presents the first model test results used to design a mine backfill. The models were tested using a 3 m radius 30 g-tonne geotechnical centrifuge which was constructed at Queen's University specifically for model studies on mine backfill stability and subsidence. The models represent the first production blast-hole stope to be mined at Westmin Resources Ltd. 's H. ~ Mine on Vancouver Island. This paper includes photographs of:model failures in the centrifuge and correlations of model test results with analyses based on unconfined and triaxial test data.IntroductionDuring the feasibility study and development stages for the H.W. Mine, Westmin Resources Ltd. conducted a comprehensive rock mechanics and backfill engineering program. The results of these studies indicated the need for assurance of backfill stability during pillar recovery on the initial blast-hole mining block. The cemented tailings backfill had to be free standing for heights up to 25 m and the potential for surcharge loading from a weak hanging wall zone, the potential for fill block sliding down-dip and the potential for seismic loading had to be considered in the design of the fill strength. The basic questions to be answered were: what cement content is required and will the resulting backfill costs be economic relative to the proposed mining method and sequence? Figure I shows a typical cross-section through the first mining block . The up-dip stope is to be mined first and backfilled with cemented tailings . The down-dip stope would then be mined and filled. Depending on ground conditions encountered, the complete intervening pillar could be recovered and the void backfilled with uncemented tailings or it could be recovered in small sections by exposing limited back and wall areas, backfilling with waste rock and I or cemented tailings . This latter method is commonly referred to as the Avoca method"

Jan 1, 1987

By James R. Kuipers

Center for Science in Public Participation CSP2 ? Organized in 1997 to provide technical assistance to public interest groups on mining and water quality issues ? 80%of effort devoted to direct support of grassroots groups and tribal governments ? 20% of effort devoted to public-oriented education for public, tribal, state and federal regulators, and for industry ? Board represented by public interest groups, at large citizens, and academia ? Professional staff with experience from mining industry, academia and government ? website: www.csp2.org CSP2 Mission Statement The CENTER for SCIENCE in PUBLIC PARTICIPATION provides training and technical advice to grassroots groups on water pollution and natural resource development issues, especially those related to mining. CSP2 seeks to focus the debate on factual issues, as brought to light by its technical analyses, and whenever possible to seek consensus and win-win solutions. CSP2 also performs policy related work with federal and state regulatory agencies on the implementation of water quality, waste disposal, and mining reclamation regulations.

May 1, 2002