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By R. Plassart, F. Laigle

"As a powerhouse, a transformer or a valve chamber, large underground caverns are a major element of hydropower plant. On the contrary to galleries and shafts which are linear and long underground structures, large caverns are designed with often complex geometries and large spans. Moreover, as these caverns are generally located on the foot of the hydraulic scheme, the high overburden is often responsible of a high stress state. Thanks to current experiences in France and around the world, the Hydro Engineering Centre (CIH) of EDF has defined great principles in the design of caverns leading to a more general methodology. The project of Tehri in India is an example of difficult ground, with in the same time a high overburden, a ductile material and an important schistosity. These physical realities are attempted to be approached in numerical modelling thanks to a constitutive law with softening behaviour and an oriented criterion integrated in the continuum model. As a result, a flexible support is advised, based on a high density bolt system and a thin lay of shotcrete. This methodology has been developed in the case of Gilboa in Israel, except the schistosity which has not been observed in situ. At last, the example of Gavet (France) illustrates a discontinuous case of numerical modelling for a good quality but fractured rock mass.PRINCIPES ET METHODES DE CONCEPTION DE GRANDES CAVERNESHYDROELECTRIQUES SOUTERRAINESRESUME Les grandes cavernes souterraines abritant les turbines, les transformateurs et certaines vannes sont des ouvrages majeurs dans les aménagements hydroélectriques. A la différence des galeries et des puits qui présentent de longs linéaires, les grandes cavernes sont des structures à la géométrie souvent complexe et avec des portées conséquentes. De plus, ces cavernes étant généralement situées en pied du circuit hydraulique, la grande couverture rocheuse peut se traduire par un état de contraintes important. Forte de ses expériences récentes en France et dans le monde, le Centre d’Ingénierie Hydraulique d’EDF a identifié de grands principes de conception des cavernes permettant l’élaboration d’une méthodologie plus générale. Le projet de Tehri en Inde est un exemple de terrain difficile, présentant à la fois une forte couverture, un matériau ductile et une schistosité marquée. Ces réalités physiques sont approchées au mieux grâce à la prise en compte dans les modélisations numériques d’une loi de comportement radoucissante avec un critère orienté intégré dans un modèle continu. Les résultats ont conduit à privilégier un soutènement souple basé sur un boulonnage systématique relativement dense associé à une fine couche de béton projeté. Cette méthodologie a ensuite été reprise pour le projet de Gilboa en Israël, exception faite de la schistosité puisque non observée sur site. L’exemple de Gavet (France) enfin permet d’illustrer un cas de modélisation numérique discontinue d’un massif rocheux de bonne qualité mais fracturé."

Jan 1, 2015

By Alastair J. Sinclair, Asger Bentzen

Abstract - A simple linear model for interpreting duplicate analytical data for a range of values is described. The conceptual model can be quantified using a reduced major axis model rather than the inappropriate traditional least squares approach. The reduced major axis parameters (slope, intercept) and associated errors provide a quantitative basis for: (1) defining bias, and (2) comparing results within laboratories, between laboratories and between sampling/analytical methods. Application of the linear model must be preceded by extraction of obvious outliers or small groups of values that have an inordinately large impact on values of the statistical parameters defining the model. In addition, consideration must be directed to the presence of more than one population of sampling error, as in the case of multiple styles of mineralization being sampled.

Jan 1, 1998

By Charles J. Zablocki, Robert J. Kamilli

"Buried, possibly mineralized granite cupolas at the Silsilah tin deposit in Saudi Arabia (lat. 26°06' N, long. 42°40' E) have been successfully located using a closely spaced electric-field-ratio profiling technique. In this study, electrical fields at 27 and 270 Hz across grounded electrodes spaced 50 m apart were measured along six traverses. This method is interpretable by inspection, unlike the dipole-dipole technique, which requires mathematical modeling for interpretation.In the study area, the technique allowed the authors to identify and distinguish among unroofed granite cupolas, cupolas with their aplite-pegmatite apical contact zones intact, strong (quartz-rich) and weak (relatively quartz-poor) greisens, dikes, faults, and pervasively argillized rocks.This method should be useful in the valuation of other shallow mineral prospects in similar settings in other parts of the world, especially deposits for which the location of vertical contrasts is important, such as veins or mineralized zones associated with the apexes of small igneous cupolas."

Jan 1, 1993

By Jochen Petersen, Alison Lewis, Cledwyn Mangunda

Run-off and waste water streams high in dissolved metal content are generated in all mining operations. The metals pose a threat to life due to their persistent bio-accumulative toxic (PBT) characteristics. Hence, there is a need to treat mine waste water effectively. Lime precipitation is the technology of choice through which Fe, as the major metal species, is removed as Fe (III) oxyhydroxides with other metals co-precipitated and/or adsorbed. Sulphates are removed as gypsum or incorporated into the Fe phases. The resulting sludge has poor dewatering characteristics and is deposited in landfills, with an inherent risk of returning the Fe back into the water cycle through leaching. This study seeks to understand the mechanisms behind the formation of this sludge in terms of product quality. The relationship between process conditions and product characteristics has been investigated through exploring the effect of Fe (III) concentration on the precipitate product characteristics (particle size distribution (PSD), size, morphology and structure) and quality (in terms of filterability, settling ability, etc.) in a simplified system. Neutralisation of acidic synthetic aqueous Fe (III) sulphate streams containing 50, 400 and 800 mg/L Fe(III), respectively, was effected by mixing it in a continuous stirred tank reactor (CSTR) with dissolved calcium hydroxide for pH control at a residence time of 15 minutes. Precipitate samples analysed for morphology and PSD, using nanoSEM and Zetasizer respectively, showed a general decrease in PSD and zeta potential with increases in feed Fe (III) concentration. These results were used to infer the particle size enlargement mechanisms of Fe (III) oxyhydroxide precipitates under a given set of operating conditions. Preliminary product quality results indicate that a high concentration (800 mg/L) leads to the rapid formation of metastable precursors with poor product quality, whilst a low concentration (50 mg/L) leads to formation of thermodynamically more stable precipitates with good product quality. The approach demonstrates a potential route forward in terms of linking operating conditions to the attainment of desirable characteristics rather than specific precipitate phases which are difficult to identify.

Jan 1, 2016

By A. C. Munro

The concrete work on the new Britannia mill was started in April, 1922. The erection of steel commenced on July 10th, following. The installation of wood work and machinery , began on November 4th of the same year and was pushed to completion in January, 1923. The new mill building is an all steel structure enclosed with galvanized corrugated steel. All main floors and foundations are of reinforced concrete, which makes the building practically fireproof throughout. The mill building rises on a steep hillside to a vertical elevation of 210 feet and has seven distinct floors, for the various opera-tions. Only one elevator, with 30-foot centres, is used in the entire mill. The building is exceptionally roomy and well lighted, both by day and night. The capacity of the mill, as originally designed, was to be 2000 tons daily, but this tonnage can be readily increased to over 3000 tons daily by making slight changes in the fine grinding equipment; in fact, an average of 2700 tons per 24 hours was maintained throughout the month of September.

Jan 1, 1923

By Patricia Dillon

EHS Management Standards Communication and Reporting (8) ! Establish processes for internal and external communications ! Designate responsibilities for communication with COI ! Report as defined by senior management ! Report annually to employees, shareholders, COI on EHS and social performance Community Rights and Public Consultation (9) !Identify COI?s and establish process to hear concerns !Acknowledge and respond to complaints !Support local communities !Plan for closure and conduct public consultation !New projects include identification of COI?s, concerns to be considered in design

May 1, 2004

By Donald F. MacDonald

METAL PRICES RISE WITHIN the past nine months, the mining industry of the world has been revivified by a spectacular price advance for the metals. ln fact, practically all geological raw materials have been marked up during this period. Reviving industry started the price rise, but the armaments race among the nations has intensified it. These factors, coupled with our decided building shortage, which must be made up, will probably maintain metal prices at decidedly favourable levels over the next two or three years, or longer. OUR MINERAL CIVILIZATION It is interesting to recall that in the past hundred years, while the white population of the world increased some three ta three and a half fold, the consumption of minerals increased seventy-five fold. In other words, ours is a mineral civilization. If we disregard short slumps, which we will occasionally experience, it seems certain that the bread upward trend in mineral consumption will be maintained for many decades into the future. Nations without reasonably abundant and diverse mineral deposits will eventually become nations without much power. Canada is blessed with a splendid store of minerals. Its mineral industry is now facing an exceptionally rosy future. What of the mineral industry of Nova Scotia? GEOLOGICAL RESEARCH ALLOWED TO LAG RN NOVA SCONA Many years ago, when geological science was in? its infancy, much geological study was carried on in Nova Scotia. In 1827, Francis Alger began work on the iron ores in the Bay of Fundy region. In 1886, E. R. Faribault began his series of remarkable papers on Nova Scotia geology. Between these dates, many others published papers on the geology of the Province. The most outstanding of this early group of geologists was Sir William Dawson, whose published works on Nova Scotian geology extended over the period from 1845 to 1891.

Jan 1, 1937

By J. S. Redpath

Eighty feet of overburden, thirty feet consisting of fine, water-bearing sands, was encountered during the construction of a shaft collar for Chimo Gold Mines Limited at its Louvicourt, Quebec, property. This paper describes the excavation and construction methods used on the project. Open-cut methods, a sheet pile cofferdam, chemical grouting and special blasting methods were used during excavation. Concrete placement was hampered in the lower portion by a heavy water flow, and aided in the upper portion by an unusual method of form bracing. Plant and • pum11ing facilities are also described.

Jan 1, 1966

By J-F. Magnan, M-A. Thibault, R. Boulianne, C. Gauthier, J-P. Gagné, G. Dufour

During the production of aluminium in smelters, the anodes used in electrolysis cells have to be replaced frequently. Anode butts are usually placed on anode trays for transportation and cooling, a practice during which Hydrogen Fluoride (HF) is emitted in large quantities. Covers developed in 2000 by Alcoa Deschambault to fit on the anodes trays were implemented, resulting in significant reductions of HF emissions. However, the covers are expensive to maintain and use short-life consumable parts. In January 2004, STAS and Alcoa decided to develop a more efficient design of cover, with lower maintenance costs and no need for consumable materials (like soft cushions). This paper presents a summary of the work performed to develop the new design as well as a summary of the test results.

Jan 1, 2006

By Robert D. Irvine

"Enhanced concern for protection of the environment and attendant actions by environ-mental regulatory authorities in support of this concern are influencing, to varying degrees, the demand and supply of a range of industrial minerals in a number of jurisdictions. These influences take a variety of forms.In this paper, the author seeks to delineate certain broad trends which are occurring relative to industrial minerals and the environment and then, through a series of examples, to outline opportunities, developments, and impacts respecting a number of industrial minerals produced and consumed in Canada and the United States."

Jan 1, 1996

By Y. O. Fortier

"ForewordTHE Arctic Archipelago and northern Greenland contain an orogenic region that is as much as 300 miles wide and over 1,400 miles long. It occupies much of what was formerly classified with the Arctic Plains and grouped with other plains and lowlands of Canada as one main geological division. It is proposed that this folded region be designated the Innuitian Region and be recognized as one of the main geological divisions of Canada.Canada's main geological divisions (see Geological Survey of Canada, 1947) have been considered as consisting of a central shield, largely surrounded by plains that separate it from eastern and western mountains. The plains include the Interior Plains, the St. Lawrence Lowlands, the Arctic Plains or Low-lands, and the Hudson Bay Lowland, which is in the central part of the Shield. Plains and mountains are, strictly speaking, physiographic terms, but because mountains are generally folded regions and plains are generally made of undisturbed strata, such terms are useful vehicles to express the fundamental make-up of the land. Nevertheless, it is preferable to use the terms Appalachian and Cordilleran 'Regions' rather than 'Mountains', as those geological divisions are not exclusively made of mountains.Because of the lack of more definite information, the 'Arctic Plains' have included, in the past, regions with plateaux two to four thousand feet above the nearby sea, mountain ranges reaching approximately 10,000 feet above sea level, and regions of folded strata."

Jan 1, 1955

By M. Silva, G. Olivares

In a leach pile, the drainage layer or commonly known as the cover layer has been a matter of discussion due to the multiple phenomena or events that occur within it which impacts negatively the leaching process. All these events are directly related to the loss of draining capacity and irregular flow net due to an excessive compaction and entrapment of fines reducing the flow velocity which in turn cause more fines to get trapped. Over time the problem will continue to worsen rapidly and accelerating continuously like a geometric progression. When the cover layer gets to a certain level of deterioration, the only alternative to continue operating safely is to replace the entire cover material, a huge cost for any mining operation. TESRA has developed a solution to counteract the accelerated advance of the deterioration of the drainage layer. The solution consists of using large agricultural tractors coupled to a proprietary design of a heavy- duty subsoiler-ripper for deep tillage for loosening and breaking up the ground at various depth and with different legs spacing from 0.4 m or above. Also, if the ground still requires additional breaking, TESRA proposes the use of a rototiller that breaks any lumps to homogenize the ground to a certain particle size. With the subsoiler-ripper/rototiller combination equipment a layer of 0.5 m deep is properly treated to match closely the original conditions of the ground thus regaining the flow net as close as to the original seepage condition. Once the ripping is completed the subsoiler-ripper tool is replaced with another that is similar to a plow and thus continue with the installation of drainage pipes. The tool digs a Y-type profile trench allowing the pipe to sit precisely at the bottom of the trench, contributing additional lateral and lower support. This tool controls the installation depth of the drainage pipe at different inclination grades and also eliminating any irregularities that may block the flow of the leaching solution. Sometimes the obstructions block completely the flow of the solution. The main result of this methodology is the reduction of groundwater levels and at least 2% less humidity in the leaching gravel due to an increase in the draining capacity of cover. The methodology developed by TESRA applied during a couple of cycles of a dynamic leach pile has proven to be a real alternative to remedy and recuperate the cover close to its original conditions. The methodology requires only one large tractor and two accessories operated in different stages while replacing the more traditional and less efficient machinery such as the Bulldozer, Motor-grader, and backhoes.

Jan 1, 2019

By STEPHEN V. FORGERON

The Loch Lamond celestite properties in central Cape Breton Island were mined by Kaiser Celestite Mining Limited from 1970 until 1976. Poor market conditions in J976forced operations to cease. Kaiser holdings included the Lake Enon, MacRae and A mac prospects. A total of about 272,000 tonnes of raw celestite have been mined. Celestite deposits are situated in the Loch Lamond Basin, specifically in Lower Windsor sedimentary rocks. Of the five formations in the Lower Windsor Group, celestite is found in the upper four. Celestite in the Enon Formation occasionally replaces shale that separates stromatolitic dolomite columns; elsewhere in the formation it occurs in association with siltstone and gypsum. Jn the B2 Limestone Formation celestite fills pores or grades between limestone and gypsum. It replaces both limestone and silty limestone conglomerate in the Loch Lamond Formation; this limestone is of unusually high grade (60 to 70% SrSO,J for the area. Evidence indicates that the Uist Formation may hold important celestite reserves. Original celestite mineralization probably resulted from evaporation of seawater on mudflats or 'sabkhas'. Secondary mineralization also may have occurred. Strontium ions could have been leached from pre-existing concentrations and overlying gypsum, moved downdip in groundwater and combined with sulphate rich waters to deposit as celestite in porous B2 limestones.

Jan 1, 1984

By Murray D. Fredlund

The consolidation of soil material is central to many types of engineering analysis. Problems such as the building of highway structures, landfills, or buildings over saturated soft clays require application of such theory. It has been found in industry that the application of consolidation theory has lagged significantly behind the theory which has been developed some time ago. The application of small-strain saturated consolidation theory was first proposed in a 1D form by Terzaghi. Although this theory has been available for some time it?s implementation into software packages in 2D and 3D forms has been slow due to inherent complexities in the coupling equations. The flow and stress equations are also inherently somewhat unstable and this further complicates software implementation. Of particular interest in the mining industry is the consolidation of uranium tailings. One such disposal method that has been utilized is the subaqueous deposition of uranium tailings in large pit structures. When performing such deposition the calculation of consolidation rates is central to determining final pit capacity and expected life. Consolidation software can be successfully used in such cases in order to determine pit filling rates. The primary complexity, however, is that tailings are typically deposited in slurry form and therefore the potential deformations are large. Large-strain consolidation theory is therefore required in order to properly solve the deformations over time. This paper presents the use of a large-strain consolidation analysis in order to predict long-term filling rates in a uranium tailings pit.

Aug 1, 2010

By J. R. del Castillo, J. Ruiz, N. Kuyucak, J. Chavez

Environmental Impact Assessment (EIA) and Feasibility Studies (FS) were carried out to evaluate the potential use of treated acid mine drainage (AMD) occurring at the Kingsmill Tunnel in the Central Andes of Peru. The 11-km long tunnel drains the underground works of the Morococha Mining District and discharges about 1.25 m3/sec of AMD directly into the Yauli River, which is located within the Amazon Basin. The communities living downstream cannot use the Yauli River water due to its low pH and elevated concentrations of metals (e.g., Cu, Zn, Fe, Mn, As, Cd) and sulfate. Studies carried out for this project included technical feasibility, EIA, economic viability and social impact assessment phases. During the "Technical Feasibility" phase, the treated AMD was produced by simulating a high density sludge (HDS) lime neutralization/precipitation process and was evaluated for various potential uses. Mining companies located in Morococha, in particular Centromin Peru S.A., and the Water Works Company of the City of Lima (Sedapal) collaborated with Golder Associates during the studies. The Canadian International Development Agency (CIDA) provided the financial assistance. The results of the physical, chemical, biological and toxicological analyses demonstrated that the treated AMD could be used for supplementing the drinking water supply of Lima and for agricultural (e.g., irrigation and livestock) and recreational purposes. Process design and scale-up parameters were also determined for the implementation of the full-scale treatment facility to the site. The use of the treated AMD as a drinking water supplement would be economically feasible.

Jan 1, 2004

By H. C. Rickaby

The Bannockburn gold area covers the four townships of Bannockburn, Argyle, Hincks, and Montrose, lying in the western part of the Matachewan district of Ontario (see Figure 1). The geology of these four town-ships was studied by H. C. Cooke of the Geological Survey, in 1917-18, and is shown in his map of the district. In the fall of 1930, a rich gold-bearing quartz vein was discovered in the northwest part of Bannockburn by B. S. Ashley. A prospecting rush followed the discovery; many claims were staked in the Bannockburn area, and, during the summer of 1931, a considerable amount of prospecting was done.

Jan 1, 1932

Mining companies around the globe have long struggled with the need to ensure that earth moving equipment is designed to be operated and maintained under all site conditions without causing harm to people. Incident and accident data from a range of sources clearly identify mining equipment related issues as major causal factors. One Australian source, the NSW Department of Primary Industries? International Mining Fatality Database Project Report (2008) noted that ?Approximately 77% of mining accidents resulting in a fatality have? involved equipment?. The largest number of fatalities were associated with trucks; the next with LHDs. Many of the technical advances in equipment design over the past few decades have not been matched by advances in the human factors design of mining equipment, resulting in a ?design vacuum? that must be filled prior to commissioning new equipment. This ?design vacuum? is generally filled by local dealers. They retrofit equipment according to customer requirements to mitigate risks that have not been designed out by the Original Equipment Manufacturer (OEM). Mining companies have been frustrated by lost time and additional costs associated with this need to retrofit ex-factory designs. Some companies have attempted to address the problem by negotiating company or site-wide ?solutions? to equipment designs, but this has not simplified or clarified the issue from the point of view of the equipment manufacturers. A number of mining companies operating in Australia first discussed the concept of a joint customer approach to improve the Human Factors design of earth moving equipment at the factory level in 2004. They agreed that a new approach to engaging with OEMs was needed; one that would define the ?Problem?, in other words, the basis of the risks, rather than dictate the ?Solution?. The Earth Moving Equipment Safety Round Table (EMESRT) was formally established in 2006 by six global mining companies to establish a process of engagement between Original Equipment Manufacturers (OEMs) and mining customers.

May 1, 2009

By Bryan Tisch

Goal of GMGE ??To advance mine reclamation through the beneficial use of organic residuals for the sustainable establishment of bioenergy crops and other productive land uses Objectives ??To advance the current ?standard? of mine reclamation by demonstrating that mining lands can safely become agriculturally ?productive? through the use of organic residuals. ??To generate and compile sound scientific data that can be utilized by stakeholders to better assess the environmental impacts of utilizing these materials. ??To complete a manual of best practices regarding the utilization of organic residuals on mine lands. *Considerable effort to be placed on operations/implementation side of utilizing residuals ?rather than just pure research

May 1, 2011

By Garry Biles, Ken Major, Raj Anand

"Prime Resources Group Inc. (Prime) commenced the Eskay Creek Mine operations in 1994 in northern British Columbia. The ore from the underground mine is crushed and shipped to smelters in Japan and Canada. The nominal production rate is 300 tonnes per day.Before commencing the above operations, preliminary evaluations for the high grade gold mine had indicated that an extremely complex metallurgical and chemical process flowsheet would be required to recover the economic metals. Subsequent to the metallurgical testing program, Prime identified markets for the untreated ore and initiated underground mining and ore transportation operations.Prime recently identified lower grade ore zones, which are less economic or uneconomic to mine and ship directly to the smelters. Test programs were initiated to evaluate processes for upgrading the ore to a marketable product. In 1997, Prime will complete the engineering and construction of a 150 tonne per day flotation plant to concentrate the gold and silver values for the NEX and 109 zones. The mine will then, in addition to the direct shipping of the shippable ore, ship concentrate from the millable ore. This paper discusses the development and design of the flotation plant.IntroductionThe Eskay Creek Mine is located in north-western British Columbia approximately 83 km north-west of Stewart, B.C. as shown in the location map Figure 1. Access to the site is provided by a restricted access gravel road from Bob Quinn Lake junction of highway 37, a distance of about 59 km. The work force at the mine is based on a two-week rotation schedule. Employees are flown from as far away as Vancouver to Smithers by commercial airlines and then from Smithers to the Bob Quinn airstrip by local charter. During poor weather conditions, transportation to site is by vans that take about six hours to travel the 450 km road distance."

Jan 1, 1998

By H. Y. Sun, Q. Y. Tan, X. P. Niu, L. Li, Y. Jia, R. M. Ruan

During bioleaching processes of sulfide minerals, the sulfide minerals act as the natural habitats for acidophiles, of which, most are autotrophic iron and sulfur oxidizing microbes. These microbes acquire energy by oxidation of sulfide minerals, and play crucial role in bioleaching processes. In the industrial bioleaching heaps, microbial community and their activity are highly related to engineering configurations, while the optimized industrial operation can help to fast dissolution of aim minerals and acid/iron balance under optimized microbial condition. Microbial community succession and activity formation, the function of microbes to mineral dissolution, the mechanisms to promotion and inhibition of sulfide minerals oxidation, and the industrial instances for microbial community regulation were reviewed. For these instances, promoted microbial activity helped to fast pyrite oxidation for sulfuric acid generation, which realized zero sulfur acid addition to the irrigation solution in the initiation of a bioleaching heaps. High microbial activity by optimized operation parameters improved Cu leaching efficiency during the heap bioleaching process. And also by inhibition of microbial activity, especially the iron oxidizing microbes, the excessive pyrite oxidation can be inhibited, which helped to the acid/iron balance during heap bioleaching. INTRODUCTION Around the world, high grade copper ore are exploited, while barely new high-grade deposits are succeeded, the copper grade of ore deposit is constantly decreasing. The increasing copper demands worldwide requests to process these low-grade ore deposits. Processing of low-grade ores are not economical by usual extraction processes. Heap leaching is a cheaper process for recovery of low-grade ores, and has been applied to extract valuable metals from sulfide minerals worldwide, such as copper, gold, uranium and nickel (Gericke et al., 2009). Heap leaching process has greatly decreased the economic grade and expanded the recoverable ore reserve worldwide (Brierley, 2008). It is usually carried out in the open environments, and could process huge amount of ore (usually in millions of tonnes in one reactor) in the heap reactor (Gericke et al., 2009). For copper sulfide, especially the secondary copper sulfides, heap (dump) bioleaching is successfully applied. Heap bioleaching process is cost saving, and sometimes can be achieved without adding chemical into heaps, by microbial fixing of the atmospheric N2 and CO2, and generating oxidant Fe3+ and sulfuric acid in heaps from oxidation of sulfide minerals. Also heap bioleaching is environment friendly by cycling use of the leaching solution, and without exhaust emission.

Jan 1, 2019