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By Frank Doxley

"FIRST OF ALL I should like to express to the members my sincere thanks for having had the privilege of serving them as President during the year now ending, to the Council for their guidance, and to the Secretary-Treasurer for his untiring efforts on both the Society's and my behalf during my year of office.During the .past five years the Canadian •Coal picture has changed considerably. In the West, production has been almost halved and many mines have been closed, due to the development and expansion of oil and natural gas industries, which, with some imported residual oil -on the Pacific coast -have provided competition which has been impossible to meet. The two major railway companies have embarked on an oil-burning and dieselization .programme and with this has .been lost one of the largest available markets for coal. Natural gas pipe-line installations still further threaten the remaining outlets for Western coal.In the East, retention of markets has also been a •problem, due to the intense competition provided by imported American •coal and the importation of residual oil.Because of cost it is impossible for central industrial Canada to be supplied with .coal from the Maritimes and markets are, therefore, restricted to fringe areas in Ontario and Quebec, and the Maritime Provinces.The dieselization programme of the Canadian National Rail ways has meant the loss of a large market for Nova Scotian coal and it is fair to assume that within a comparatively short time the market will be completely lost."

Jan 1, 1955

By Junior Santos

Kinross Paracatu started the operation of the new gold processing plant in the end of 2008, being composed by one SAG mill and two ball mills. During the first year of operation the plant had several problems related to stability and throughput capacity, mainly due to low grinding efficiency of the ball mills. In this period many actions were taken to maximize the throughput rate. Among the actions are reducing the size of balls in the mills, increasing the ball charge in the SAG mill, changing cyclone configuration and return of circulating load to SAG mill. With better stability of the circuit, the second stage of improvements has begun with the objective of increasing throughput rate and also reducing operation costs. Among the actions are the optimization of ball charge in the mills and a better operational control of cyclone parts. After two years of operation was obtained a significant increase in plant capacity, but still requires the addition of a third ball mill in order to maximize the use of SAG mill, which has spare capacity.

Jan 1, 2012

By Ray Walton, Ron Colquhoun, Ken Thomas, Dwayne Fentie, Barney Burke

"The new Roasting Facility at Barrick’s Goldstrike Mine in Nevada, U.S.A. was developed to process 12,000 tons per day of refractory gold ore. The process consists of crushing, dry grinding, roasting, extensive gas purification, calcine quenching and leaching in the presence of activated carbon. The new plant is integrated into the existing Goldstrike facility, treating ore from both open pit and underground sources.The process design, procurement, construction and commissioning of the Roaster facility was performed successfully over a 3% year period with peaks of 400 engineering personnel and 950 construction personnel supporting the project. The US$330,000,000 project was completed ahead of schedule and under budget. The commissioning was well planned and proceeded smoothly through a rapid start-up to achieve all primary goals within three months of the start of processing of ore.BACKGROUNDAs early as 1992, Barrick’s Goldstrike Mine, located north of Carlin, Nevada had indications of the ore becoming ever increasingly carbonaceous in nature. As the open pit and underground exploration programs proceeded to step out over the years that followed, the accumulative amount of carbonaceous refractory ore and tons had become significant. By 1997, 29 million tons of double refractory carbonaceous ore containing an estimated 11.6 million ounces of gold had been identified. By 2000 the resource had increased to 14.3 million ounces."

Jan 1, 2001

By A. Ignatieff

"THE WORLD'S coal resources represent the largest component of non-renewable energy resources. Coal is now regaining Its position following a temporary decline, particularly in North America during a period of about a quarter of a century. This period provided the opportunity to improve both surface and underground mechanization, thereby increasing the productivity and improving conditions for humans in the mines. Similarly, in preparation, improved cleaning of coal from various impurities including sulphur was achieved, to meet the more demanding requirements for coking coal. Progress was also made in combustion, particularly related to the reduction of pollution. Canada participated in most of these developments, despite the country's strong commitment of the use of hydrocarbons during this period. _Bearing in mind the vastness of this land (3.85 million sq. miles) by comparison with countries like U.S.A., U.S.S.R., and China, Canada's coal resources estimated to date are not large and they are scattered. The original evaluation of 1913 estimated the ""reserves"" from seams over one foot in thickness and a limiting depth of 4,000 ft at 1.2 trillion metric tons. D:. ~.R. MacKay, in his evaluation for the 1946 Royal Commission on the coal industry, known as the Carroll Commission, reduced the ""reserves"" to 99 billion short tons. The increased knowledge now available would indicate that the 1913 estimated was too liberal and the 1946 estimate too conservative but both were closer to a resource than to a reserve designation. Some adjustments of Dr. MacKay's estimates were made in 1970 by B.A. Latour of the Geological Survey of Canada and L.P. Chrismas of Energy, Mines and Resources Canada (EMR). In the last decade the Alberta Energy Resources Conservation Board has developed its own methods of evaluating coal resources and reserves. A methodical approach of exploration and evaluation was carried out by Saskatchewan jointly with the federal government of the lignite resources of Southern Saskatchewan. A similar joint program is in progress in Nova Scotia. Meanwhile, the industry itself carried on an extensive exploration program on the outcrops of promising projects in the Inner Foothills belt of Alberta and British Columbia in preparation for surface mining on a very large scale, with some development of hydraulic mines. All these activities have been reflected in the increase of the country's resources and reserves, which now fortunately are separately defined. In 1979 EMR issued Report E.R. 79/9(1>; the data were developed in 1978 and provided to the World Energy Conference Organization<2>. In 1980 the World Coal Study (Wocol), an international group that included Canada carried out a study which updated the W.E.C. data, indicating some reduction of the 1978 figures; quantities were reported in million metric tons of coal equivalent (C.E.)*(Jl."

Jan 1, 1985

By Limao Zhang

This paper presents a novel model to assess the risk of adjacent buildings in tunnelling environments based on Extended Cloud Model (ECM). ECM is an organic integration of Extension Theory (ET) and Cloud Model (CM), where ET is appropriately employed to flexibly expand the variable range from [0, 1] to (-8, +8), and CM is used to overcome the randomness and fuzziness during the gradation of evaluation factors. The risk level of a specific adjacent building is assessed by the correlation with the cloud models. A confidence indicator ? is proposed to illustrate the rationality and reliability of evaluating results. Ten buildings adjacent to Wuhan Metro Line Two (WMLT) are randomly chosen among hundreds of adjacent buildings for a case study. Results have proved to be consistent with the actual situation. Compared with other traditional evaluation methods, ECM has been verified to be a more competitive solution with high calculation accuracy, wide adaptability, as well as simplified computer programming. There are no stringent requirements on the quantity of training data during the modelling process, and the original data can be directly entered into ECM without a normalization procedure, avoiding the potential information loss. ECM can be offered as a decision support tool for the risk assessment in urban tunnelling construction and worth popularizing in other similar complicated projects.

Aug 1, 2013

By Neri Roux, Chris Budgell, Allan Cramm, Leo Cheung

"Anaconda Mining Inc. is investigating potential improvements and expansions to their operating plant located on the Baie Verte Peninsula in Newfoundland. An extensive batch and continuous bench scale testing program was launched to investigate the efficiency of cyanide destruction under different conditions in order to improve tailings handling. The primary objective of the cyanide destruction study was to apply new technologies to develop a novel cyanide destruction system.Effluent and slurry from Anaconda Mining Inc.’s Point Rousse Project was received at RPC where test work was conducted. Various sodium metabisulfite (MBS) dosages were evaluated and the use of utilizing ozone and ultra violet (UV) light to oxidize cyanide was investigated. All the data was evaluated and mass balances were compiled to develop several flowsheets. Overall encouraging results were found using a combination of ozone and MBS.IntroductionAnaconda Mining Inc.’s Point Rousse project includes an operating gold processing plant located on the Baie Verte Peninsula in Newfoundland which is in the process of improving and expanding. This plant comprises of milling and flotation followed by cyanide leaching in order to extract the gold. The residue from cyanide leaching is filtered by drum filters prior to being clarified for the Merrill-Crowe process. Once the gold has been recovered by the Merrill-Crowe process the effluent is filtered by filter presses and the resulting filtrate as well as the solids from the drum filters are detoxified prior to being pumped to the tailings pond along with the flotation tailings.The entire process is very dependent upon the efficient destruction of cyanide in the effluents and successful tailings handling. Substantial amounts of effluent are delivered to tailings ponds after gold extraction which could create environmental problems if the regulations are not met. Environmental regulations stipulate that final effluents contain no more than 1 mg/L Total CN.The detoxified tailings of the Point Rousse project are produced by the INCO SO2-Air circuit depicted in Figure 1. These detox tailings contain 10 mg/L Total CN at that point of the circuit and this was selected as the target to be matched while reducing overall MBS consumption rates from 3.2 g/L per minute. Prior to detoxification, the filter press tailings contain 520 mg/L Total CN while the drum tailings contain 29 mg/L Total CN."

Jan 1, 2017

By C. Piribauer, E. Feichtenhofer, A. McEneaney

"As part of a major diversification project, RHI AG, through its plant in Drogheda Ireland, has developed a Caustic Calcined Magnesium Oxide (CCM) for use in the Cobalt (Co) & Nickel (Ni) hydrometallurgical extraction industry. In the course of the project, the company investigated the chemical and physical properties of a number of different Magnesia’s used in Co & Ni hydrometallurgy applications and has been able to determine the important parameters for a successful Magnesia for this application. A number of live plant trials have confirmed the results of this testwork and the company is now proceeding to produce this product in commercial quantities at Premier Periclase Ltd., the RHI AG plant in Drogheda, Ireland. This paper will outline the development work conducted by the company and highlight the important chemical and physical properties that make a successful CCM. Much of the research was conducted at the RHI Technology Centre in Leoben, Austria. In addition, a number of external laboratory studies were conducted on behalf of RHI AG. The result of this work has allowed the company to develop a Magnesia product with optimised properties for use in the Cobalt and Nickel hydrometallurgical extraction process.INTRODUCTION Premier Periclase is part of RHI AG, a globally operating supplier of refractory products, systems and services, headquartered in Vienna, Austria. The company produces Magnesia from seawater at its plant in Drogheda, Ireland. While the main focus is on production of refractory grade Dead Burned Magnesia for the steel industry, the plant also produces a number of different grades of Caustic Calcined Magnesia as well as Magnesium Hydroxide products. As part of a major project to diversify the company’s product base, the use of CCM in the Cobalt (Co) & Nickel (Ni) hydrometallurgical extraction industry was investigated. One of the company’s highly reactive grades of Caustic Calcined Magnesia was found to be particularly suitable for this application. In an effort to understand what makes a successful Magnesia for hydrometallurgy the chemical and physical properties of different Magnesia’s used in Co & Ni hydrometallurgy were investigated. This paper and conference presentation outlines the findings of this process."

Jan 1, 2017

By D. Pawelus, J. Butra, R. Debkowski, M. Szpak

Impact of horizontal stresses on stability of underground workings in mines is a very important issue in underground mining. Identification of the initial state of stress in the rock-mass should be one of the main actions taken into account while designing and carrying out the mining activity in underground mines. The paper presents the tests on three dimensional stress pattern in Polish copper mines, owned by KGHM Polska Miedz S.A. Group, carried out in 2012. The research program covered 7 measuring stands in two mines; their average depth was about 1000 m. The main aim was to identify the values and directions of horizontal stresses in order to optimize the extraction and to improve the safety. The overcoring method with the use of CSIRO HI type probe was applied. The paper also describes the measuring technique which was developed for the purpose of specific mining and geological conditions of KGHM mines, taking into consideration the natural hazards encountered there as well as technical and operational capabilities with regard to drilling equipment. The experience gained during the underground measurements and the issue of making such measurements in underground copper mines in Poland are presented in the paper. The stress patterns obtained during the underground measurements are of application importance for the process of designing the spacing of mine workings and improving their stability and mine support selection.

Jan 1, 2015

By Jérôme Girard, Shiu Kam, Sue Longo

"Historically, tailings management in a northern climate has involved the deposition of tailings into the Tailings Management Area (TMA) as conventional slurry. This type of system is obviously viable but presents challenges that are difficult to manage as circumstances change over the life of mine. These issues can include:? Increases in mill throughput, and? Life of the TMA for the life of mine.This case study will present how thickened, high-density, non-segregating tailings are used as an alternative to conventional slurry disposal to achieve greater storage capacity and enhanced environmental performance for a gold tailings facility in a northern climate. This paper will focus on how this change in deposition strategy accommodated the increased throughput of the mill and the increased life of mine. Specifically, the paper will discuss the addition and integration of new processes to the exiting mill system to accommodate the tailings management issues. It will highlight the challenges from laboratory testing to pre-feasibility to the engineered design of the thickened tailings system implemented at Musselwhite Mine.BACKGROUNDGoldcorp Canada’s Musselwhite Mine, in Northwestern Ontario (120 km north of Pickle Lake), is an underground gold mining operation that began production in 1997. The current mill throughput is about 4000 tpd (1.4 Mtpa). Gold extraction is based on a CIP process with cyanide destruction.The existing tailings management area (TMA) is located about 2 km southwest of the mill complex. The TMA is contained by high ground to the north and to the west and flanged by a moraine ridge along the south side. A number of dams have been constructed along this ridge. The dams were first built in 1996 and subsequently raised in 2000 and again in 2005. Excess tailings pond water is discharged to a polishing pond then released to the environment via a wetland.The TMA was originally designed to contain 13.7 Mt of tailings under a ponded surface for closure. The water cover was to inhibit adverse long-term environmental effects because the tailings contain pyrrhotite and other sulphide-bearing minerals that are potentially acid generating. The design was modified during Stage 3 Construction in 2005 to expand the storage capacity to 17.3 Mt (Golder, 2005). As of end of 2009, over 16 Mt of tailings had been deposited in the TMA. The slurried tailings were historically deposited at 50% solids."

Jan 1, 2011

By B. Kenney

For SOFCs, composite cathodes comprising an electronically conducting electro¬catalyst (e.g. LSM) and an conically conducting electrolyte material (e.g. YSZ) are considered to improve the electrochemical performance by extending the active reaction zone to regions beyond the electrolyte-electrode interface, as in the case of conventional cathodes. Interpretation of experimental data for composite cathodes, however, is complicated by the mixed conducting behaviour which results in local overpotential distributions throughout the composite cathode. These local overpotentials depend on many factors, such as the composition, particle size, porosity and thickness of the cathode. Reliable experimental data obtained from composite cathodes requires carefully crafted microstructural parameters in order to minimize the overpotential variations. A mathematical model of a composite cathode was developed using coupled differential equations describing transport and consumption of chemical species, oxygen ion and electrons. Simulations under various oxygen concentrations were used to obtain the reaction order of the oxygen reduction reaction. An apparent po2 dependency was then extracted from the predicted Rp vs P02 data. It was found that this p02 dependency can be significantly influenced by the micro-structural parameters of a composite cathode, primarily due to local overpotential distributions.

Jan 1, 2005

By H. O. Ghaffari

A complex network approach on a rough fracture is developed. In this manner, some hidden metric spaces (similarity measurements) between apertures profiles are set up and a general evolutionary network in two directions (in parallel and perpendicular to the shear direction) is constructed. Also, an algorithm (COmplex Networks on Apertures: CONA) is proposed in which evolving of a network is accomplished using preferential detachments and attachments of edges (based on a competition and game manner) while the number of nodes is fixed. Also, evolving of clustering coefficients and number of edges display similar patterns as well as are appeared in shear stress, hydraulic conductivity and dilation changes, which can be engaged to estimate shear strength distribution of asperities.

May 1, 2009

By C. Moreland

Fluidized low-temperature carbonization of coal, a recent development, offers a possibility of reducing fuel costs of coal-burning electric ?generating plants. The Research Council of Alberta have built a pilot plant and are conducting a programme to -develop a carbomzation plant for Alberta sub-bituminous coals which will produce char suitable for use as a .boiler fuel, and tar of a potentially high value as a ?chemical raw material. The economies of the process as a whole, and the value of the tar, have yet to be assessed.

Jan 1, 1958

By Milton Fies

Introduction The first experiment in underground gasification of coal in the United States was conducted at Gorgas, Walker county, Alabama, under a co-operative arrangement between the U.S. Bureau of Mines and the Alabama Power Company, at the suggestion of the Power Company. The test was conducted on property of the Alabama Power Company, that owns some 19,000 acres of coal-bearing lands on which there is developed a highly mechanized mine producing some 2,500 cons of good quality steam coal per day. At the same locality ?there is a 200,000 kilowatt steam plant one of the largest in the southern portion of the United States. The Alabama Power Company owes much of its beginning in 1912 to British vision and courage. The original plans for building hydroelectric plants in Alabama, and for the construction of necessary transmission lines, were submitted to Sperling & Company, bankers of London, who agreed to underwrite certain bond issues, the proceeds of which would be used in launching the new Company on its programme. The set-up by which these funds from England were received was through an intermediary Canadian company, which the English investors desired. The Canadian company - Alabama Traction, Light and Power Company, Ltd. became owner of the securities of the Alabama Power Company and marketed its own securities through the banking house of Sperling & Company. Without assistance at this time the Alabama Power Company could not have gone ahead with its programme of expansion and the bringing together of the properties necessary for laying the foundation for a strong Company, fortified with ample power resources essential for future requirements and for dependable service to the public.

Jan 1, 1948

By Gerald Blackmore

This paper discusses the present state and future trends within the coal industry, and then goes into the reasoning behind these planned trends. Such factors as marketing, costs, new mining techniques and machinery, and manpower and human resources are considered. Finally, the author refers to the effect that these trends will have on the coal industry of Cape Breton.

Jan 1, 1968

By O. P. Garg

Based on improved methods of collection and analysis of geotechnical data, slope angles have been steepened in some mines of the Iron Ore Company of Canada at Schefferville, Quebec. This paper describes the slope design case history for Fleming NO.3 mine and illustrates the application of modern techniques. The new design has resulted in significant financial savings due to a reduction in required waste stripping.

Jan 1, 1978

By Jack Zhang, Yunguo Tang, Baodong Zhao

"Rare earth elements (REEs) have numerous key applications in both traditional and advanced technologies. A shortage of some critical REEs is expected due to the discrepancy between the REE abundance in REE deposits and the REE demand from the market. For example, Neodymium, Europium, Terbium, Dysprosium, Erbium and Yttrium are expected to be in short supply. REE recovery and separation from secondary resources such as uranium wastes, heavy mineral sands, and recycled materials can balance the shortfall in a cost effective way.The Saskatchewan Research Council (SRC) is engaged in the development and commercialization of complete REE recovery and separation technologies in Canada. One of SRC’s newest developments is the design and commissioning of a heavy rare earth (HREE) separation pilot plant. The pilot plant uses hundreds of stages of solvent extraction (SX) to produce high purity individual HREEs from both primary and secondary resources.This paper presents the design of an HREE recovery process for the particular case of uranium processing wastes. The separation results of a group separation are reported and discussed, as well as the issues and the challenges of the development, commissioning and operation of the continuous SX pilot plant.IntroductionSignificant amounts of strategic specialty heavy rare earth elements (HREEs) are found in uranium wastes in Saskatchewan. It estimated that about 47 tonne/a of heavy rare earth element oxides (HREO) including 27 tonne/a of Y2O3, plus 6 tonne/a of Sc2O3 are in the raffinate of every uranium mill for potential recovery. Since the HREEs are already in the raffinate, cost effective HREE production is promising in Saskatchewan.Selective precipitation including nutraulization, oxalate and double-salts precipitation, as well as sulfide precipitation, ion exchange (IX) and SX are commonly used technologies for the recovery and purification of REE solution. REE oxalate precipitation is an effective technology to remove Fe, Al, Ca, Si and other impurities by taking the advantages of the solubility difference between oxalates of REEs and impurities in acidic solution (Xu, 2005)."

Jan 1, 2017

By Laura Mottola

Process Design and Change Management for Successful Deployment of Technology in Mining Over the last 30 years Canada has been successful in developing but not deploying hardrockmining automation. Our opinion is that the current lack of R&D investment and implementation capacity places Canada at risk as a future global mining leader A white elephant A burdensome possession; creating more trouble than it is worth. White (albino) elephants were regarded as holy in ancient times in Thailand and other Asian countries. Keeping a white elephant was a very expensive undertaking, since the owner had to provide the elephant with special food and provide access for people who wanted to worship it. If a Thai King became dissatisfied with a subordinate, he would give him a white elephant. The gift would, in most cases, ruin the recipient.

May 1, 2010

By Bennett McLaughlin

AGNICO-EAGLE started sinking the Penna Shaft in 1995 with a hoisting plant capable of hoisting 1,800 tonnes per day from a 2,240 metre deep shaft. Exploration success lead to the installation of a hoisting plant capable of extracting 4,500 tonnes of ore and 1,800 tonnes of waste per day from a depth of 2,210 metres. The introduction of a new rope selection factor, permitting a safety factor of 4.0, represented the breakthrough required for a cost-effective project. This paper describes the process taken to introduce the new rope selection factor and its impact on the original plant.

May 1, 2001

By A. Hutwalker, T. Plett

"Blast fumes are one of the major sources for NOx in underground mines. In 2016, the Occupational Exposure Limits for NOx in Germany were reduced by 90%. The task is to keep re-entry times after blasting at the present level and thereby ensure an economic operation of the mine. Measurements show that using ventilation solely is not sufficient. A new approach to reduce NOx from blast fumes is described. Laboratory experiments were performed and a reduction of NOx was observed. Measurements were conducted at an explosive factory’s testing facility and in an underground mine at blasting operations. INTRODUCTION Whether for production of ore or for drift development, the processes in an underground mine are always the same: 1) fracturing the rock, 2) loading the pile, 3) support the resulting cavity. The fracturing of the rock can be done mechanically, by cutting, for example by using continuous miners or tunnel boring machines, or by drilling and blasting. Drilling and blasting is more flexible than mechanical driving, as it can be used independently of the rock strength. Furthermore, this driving method allows a more flexible reaction to changes in geological and/or operational conditions. Thus, underground mining and blasting are almost inextricably linked with each other, and regardless of the size and level of technology of the mine, blasting is hardly avoidable. Depending on the mining method chosen and the existing framework conditions, such as the mechanical properties of the rock or the availability of machinery, blasting is an integral part of daily operations. Even in mines where blasting is not part of regular operations, it cannot be completely avoided. The blast fumes generated by the explosions are, in addition to diesel engine emissions, one of the two main sources of emissions of nitrous gases underground. Up to now, state of the art for dealing with blast fumes is ventilation. The fumes are diluted with fresh air and ventilated out of the mine. This treatment of blast fumes is more than sufficient with the former German Occupational Exposure Limits (OEL). The adaption of the OEL in Germany to the recommendations of the Committee on Occupational Exposure Limits (SCOEL), a committee of the European Commission, leads to big challenges for the mining industry in reducing the concentrations of these gases at the workplaces underground. On its meeting on May 2nd and 3rd 2016, the Committee on Hazardous Substances (Ausschuss für Gefahrstoffe, AGS), an advisory body of the German Federal Ministry of Labour and Social Affairs (BMAS), advised the BMAS to copy the OEL, as recommended by the SCOEL, to the Technical Rules for Hazardous Substances (TRGS 900). BMAS followed this advice, consequently the new OEL where published on November 4th 2016 and became part of the TRGS 900. Table 1 shows the former and new OEL for Germany. These new OEL became law after publishing, but two exceptions were made: For tunneling operations, they became law on October 31st 2017, for mining operations they will become law on October 31st 2021 (BAuA, 2004, 2016, 2017)."

Jan 1, 2019

By Benjamin A. Allou

La seule production de columbo-tantalite réalisée en Côte d?Ivoire est effectuée dans les éluvions et alluvions du gisement d?Issia, localisé au Centre- Ouest de la Côte d?Ivoire. Même si un lien direct avec les roches granitiques est suspecté, aucune attention particulière n?a été accordée à l?étude de la minéralisation primaire en relation avec l?évolution des granites et des pegmatites associées. Ces granites, qui sont en intrusion dans les roches sédimentaires du Protérozoïque inférieur, comprennent : le granite orienté à deux micas (Lobo), le granite orienté à muscovite dominante (Bitapia) et le granite porphyroïde non orienté à muscovite dominante (Issia). Les résultats de cette étude indiquent que les pegmatites à Nb-Ta-Be-Li sont liées au granite de type Issia. Les observations de terrain et les analyses sur roche totale des granites montrent que: (1) les trois principaux granites de la région sont de type- S et peralumineux dans leur composition, (2) ils ont été formés pendant la période tardi- à post-Éburnéenne, (3) le granite d?Issia fut le dernier à se mettre en place. Les pegmatites liées au granite d?Issia ont été classées en quatre types : Apegmatites stériles; B- pegmatites à Be; C- pegmatites zonées à Nb-Ta-Be; et Dpegmatites zonées à Be-Nb-Ta-Li. Les pegmatites zonées comprennent les zones suivantes: I- zone à aplite; II- zone graphique; III- zone à albite, microcline, béryl et columbo-tantalite; IV - zone à microcline massive; V- zone à quartz. Ces pegmatites présentent une zone d?altération métasomatique externe. La minéralisation de Ta, Nb et Be est liées à la zone III des pegmatites de types C et D, et celle de Li est associée aux greisens qui peuvent être observés n?importe où dans les pegmatites de type D. Les données de terrain et de laboratoire indiquent que le granite d?Issia est la roche parentale des pegmatites à éléments rares de la région. Les pegmatites minéralisées sont distribuées seulement autour du granite d?Issia et les patrons des terres rares des granites et ceux des pegmatites à éléments rares sont très similaires. Les analyses de la composition totale montrent un lien génétique entre le granite d?Issia et les pegmatites à éléments rares. Il est suggéré que les pegmatites ont été formées durant le transport et la cristallisation fractionnée du magma.

May 1, 2003