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By José Carlos Abreu

This work presents a kinetics study covering the effects of temperature over the reduction rates of a carbon composite briquette, aiming its use as burden in some of the new alternate ironmaking technologies, such as the Tecnored process. It is reported that increases in the temperature increases the reaction rate. Additionally, the morphology of the iron phase generated during the reduction of these briquettes is presented. It was possible to verify that three types of iron morphology occurred during the process: an external, dense and continuous iron layer, the presence of iron globules at the center of the briquettes and whiskers at the briquette's core. The measurement of the carbon content on the globules and the external iron layer is also presented

Jan 1, 2003

"In 2000 the CIM Council approved the CIM Standards on Mineral Resources and Reserves – Definitions and Guidelines, developed by the CIM Standing Committee on Reserve Definitions. The Definition Standards established definitions and guidelines for the reporting of exploration information, mineral resources and mineral reserves in Canada. The Mineral Resource and Mineral Reserve definitions are incorporated, by reference, in National Instrument 43-101, Standards of Disclosure for Mineral Projects, which came into force in Canada in February 2001 and was amended in December 2005.CIM DEFINITION STANDARDS- For Mineral Resources and Mineral ReservesPrepared by the CIM Standing Committee on Reserve DefinitionsAdopted by CIM Council on December 11, 2005FOREWORDCIM Council, on August 20, 2000, approved the ""CIM Standards on Mineral Resources andReserves - Definitions and Guidelines,"" developed by the CIM Standing Committee on ReserveDefinitions. The CIM Definition Standards on Mineral Resources and Reserves (CIM DefinitionStandards) establish definitions and guidelines for the reporting of exploration information,mineral resources and mineral reserves in Canada. The Mineral Resource and Mineral Reservedefinitions were incorporated, by reference, in National Instrument 43-101 - Standards ofDisclosure for Mineral Projects (NI 43-101), which became effective February 1, 2001.At the August 20, 2000 Council meeting a new CIM Standing Committee on ReserveDefinitions was established consisting of the following: John Postle, Bernie Haystead, LarryCochrane, Normand Champigny, Mike Hoffman, Colin McKenny, Jack Mullins, Phil Olson,Fred Payne, Jody Todd and Joe Ringwald.Subsequent to the publishing of the August 20, 2000 CIM Standards on Mineral Resourcesand Reserves, various CIM committees have compiled and published more extensivedocumentation on mining industry standard practices for estimating Mineral Resources andMineral Reserves. These standard practices provide more detailed guidance than that containedin the August 20, 2000 CIM Standards on Mineral Resources and Reserves. On November 14,2004 CIM Council adopted an update to the CIM Definition Standards to reflect the moredetailed guidance available and effect certain editorial changes required to maintain consistencywith current regulations. This version of the CIM Definition Standards includes further editorialchanges required to maintain compatibility with the new version of National Instrument 43-101which is expected to become law at the end of 2005. The CIM Definition Standards can beviewed on the CIM website at www.cim.org."

Jan 1, 2003

By E. B. Kroeger

One of the problems encountered when constructing a roadway is the planned route often needs to cross soils that are soft and highly compressible. An approach to dealing with soft and compressible soils is to construct the fill from lightweight materials, thereby reducing the stresses on underlying soils. Most lightweight fills have approximately the same cost, so the most important consideration when choosing a lightweight fill is that the material properties of the lightweight fill match the conditions existing at the site. Expanded polystyrene (EPS) has been used as a lightweight fill material for more than 30 years. The EPS used for road fills is typically in the range of 0.5 to 2 lb/ft3, and has a compressive strength of in the range of 10 to 30 lb/in2. If a higher strength material is needed, then the material density is increased, which also adds to the cost of the material. Another type of lightweight fill material that is commonly being used is lightweight aggregate (LWA). LWA can be created by passing slate or shale through a rotary kiln or reheating coal fly ash with other materials to form pellets or aggregate. Several companies throughout the U.S market these materials under a variety of names. LWA can have a unit weight from 45-80 lb/ft3. For sites where trucking granular fill does not pose a problem, this material may be an alternative to EPS. One of the drawbacks to using LWA is the availability of the material. Only a few companies are manufacturing LWA, so it may not be available or may be cost prohibitive in certain areas of the country. Lightweight flyash blocks have been produced which may fill the gap in unit weight between the EPS and LWA. Blocks have been produced with a unit weight as low as 30 lb/ft3. They are relatively inexpensive, easy to handle, and have a moderate compressive strength. Although the unit weight is dramatically higher than EPS, the strength is also higher. If lateral stabilization of the fill is a problem, then geofabrics or grids can be incorporated into the design to add lateral strength.

Jan 1, 2003

By Freddy Pøhner

The paper describes recent advances in the technology for mapping of the seabed with acoustic instrumentation. These instruments are typically single beam echo sounders, multibeam echo sounders and high resolution sub bottom profiler. For the single beam echo sounders, new features for deep water mapping are described, as well as the possibility for combining investigation of shallow areas with side scan sonar and vertical echo sounding in the same instrument. Multibeam echo sounding technology for deep and shallow water is reviewed, and some new high resolution instruments using dynamic beam focusing is presented. The sediment profiling technology deals with a novel design for high resolution sub bottom profiling, based upon a Mills Cross transducer with resolution as good as 3 degree in its largest configuration and a frequency range of 2,5 ? 7 kHz. Remarkable features of the system are a very high ping rate even for deep water, and the capability to map buried objects or structures by several simultaneous beams. Some results obtained with the first installation on the French research vessel ?Beatemps Beaupré? are presented.

Jan 1, 2003

By M Ujihira, M Komazaki, K Higuchi, D F

A diesel engine with a misfiring cylinder is likely to break down in a short time when the engine is used without maintenance. The authors have developed a method of detecting the occurrence of cylinder misfiring and specifying the misfiring cylinder by using wavelet analysis and statistical analysis on the root mean square (r.m.s.) values of two kinds of acceleration waveforms. This detection method is considered superior to traditional methods, which require several accelerometers, especially in terms of simplicity. Since the development of the method, research has been conducted on semi-automatic processing of measured signals and signal transmission from the worksite to a remote office. Field tests confirmed that 1 + 105 points of dynamic data could be transmitted through the mobile multimedia network within 15 minutes, and the time for signal processing was within 15 minutes. Final determination on the condition of a diesel engine in heavy machinery could be achieved within 30 minutes. Shortened processing time is expected by improvement of the processing software.

Jan 1, 2003

By Alim Gül, Güven Önal

"Recently, there have been some attemps on the treatment of low grade ores and old plant tailings due to the decrease in high grade ores and the increase in the metal consumption with increasing world population. Cost of mining and beneficiation of low grade ores become prohibitive since the costs of grinding before flotation make the process unfeasable. Therefore, preconcentration of these ores prior to flotation becomes more important. The concentration of ores preconcentrated in coarse sizes provides a decrease in investment costs as well as grinding and flotation costs. Additionally, the requirements of less space for tailing disposal and less reagent consumption are also important from the viewpoint of environmental considerations.In this study, ore sample containing 0.6 % Cu and taken from Küre-Asiköy ore body was used. Ores contained chalcopyrite and pyrite as main minerals and diabaz, quartz, chlorite and sericite as gang minerals.Samples were all crushed under 9 mm by considering the preliminary studies and float and sink experiments were carried out with the sample in the size range of –9+1 mm using different densities of heavy liquids. As a result of these tests, it was shown that 60 % of the material should be discarded as tailings with 0.1 % Cu content. By considering float and sink test results, the following experiments were performed by using heavy medium cyclone and jigs.As a result of heavy medium cyclone tests, which are conducted on the sample in size range of –9+1 mm, 57 % of the feed material was discarded as tailing with 0.08 % Cu content and 7 % Cu loss, while a concentrate containing 1.43 % Cu was produced with 93 % efficiency (Table 1). Jig tests were done with the samples in the size range. As a result of jig tests with –9+1 mm size group sample, approximately 46 % of feed material was discarded as tailings with 0.13 % Cu content and 10.6 % Cu loss, while a concentrate with 0.94 % Cu content was obtained (Table 2)."

Jan 1, 2003

By Michel Claisse, R. P. Goel, André J. Rancourt, Kent Murphy

The Malana Hydroelectric Project is a private development located in HimachalPradesh State, India that was commissioned in June 2001. The plant was built and is owned by the Malana Power Company, a subsidiary of the Bhilwara Group of New Delhi. With a total head of 400 m and nominal capacity of 86 MW, the plant is capable of generating 360 GWh annually. The 3,1 km long, 4,0 m diameter power tunnel was designed to be excavated by conventional drill and blast methods. Contrary to traditional practice in India for pressure tunnels of providing a concrete lining, the Malana tunnel was finished mainly with shotcrete. In this way, the tunnel was completed in a period of18 months, a record for recent projects in the Himalayas, and at a cost substantially below that of conventionally lined tunnels. An interesting aspect of the project was the design of the steel tunnel liner linking the power tunnel to the penstock. The length of the liner was fixed finally on the basis of in-situ testing using both hydraulic jacking and doorstopper tests to evaluate the ability of the rock to withstand the internal pressure of4,0 MPa that exist near the downstream end of the tunnel.

Jan 1, 2003

By E Werner, J J. Donovan, A J. Morris

Coal mining in the Pittsburgh coal seam, in the eastern United States, began in the late-1700s. Since that time numerous mining technologies have been used throughout the basin. Environmental concerns, particularly mine discharge quality, have only been considered since the early-1970s. During the last 20 years, many of the larger underground mines have closed and are now either flooding or already flooded. In order to understand the consequences and potential future effects of this flooding, mine mapping of the basin has been compiled utilising a geographic information system (GIS) with an emphasis on locating barrier pillars between mines. Mine flooding has been monitored at numerous sites utilising pressure transducers and data loggers. These data have been combined with historical data from mining companies and structure contour maps to yield chronological flooding maps of the basin from 1980 to present. Utilising these maps and the indicated flooding rates, future discharge locations have been identified along with estimates of when these discharges are likely to occur. Related work has identified barrier pillar hydraulic conductivities and vertical infiltration rates as a function of overburden thickness. All of this information has been integrated into a groundwater flow model that simulates mine flooding. This model is useful in defining mine to mine interactions as the various mines fill with water, and the testing of various flooding scenarios. The model will be used in evaluating mine discharge rates and evaluating the options for regional mine drainage treatment.

Jan 1, 2003

By Sri Sawmliana, P. Pal Roy

Blasting Gallery (BG) method was introduced in India for higher production and low cost of excavation to substitute conventional hand section and stowing methods for thick coal seam. The Singareni Collieries Company Ltd. (SCCL) adopted this method in the year 1989 and since then successfully operating at GDK-10, GDK-8 & VK-7 Incline mines in Andra Pradesh, a southern state of India. It is also successful at Chora 10 Pit Colliery of Eastern Coalfields Ltd. (ECL) in West Bengal whereas at East Katras Colliery of Bharat Coking Coal Ltd. (BCCL) in Jharkhand State, the method has been partially successful due to some geological constraints of the area.

Jan 1, 2003

By Robert T. McKnight

"Traditional techniques for valuing resource projects companies have been primarily based on discounted cashflow methods (DCF) or by comparison to similar projects with an apparent market capitalization. Many resource projects are really forms of options to invest rather than a future cashflow stream. Employing the DCF method to value a resource project which is really an option to invest, can dramatically underestimate the real value of the project. The analytical tools required to evaluate options, while more complicated than the usual spreadsheets used for DCF, are becoming more easily available and usable by managers. This paper will discuss the background of options valuation and some of the tools which will make it easier for managers to estimate the value of projects and companies which have significant real option values.ResumeBob McKnight is a graduate of the University of British Columbia in Geological Engineering, supplemented by an MBA from Simon Fraser University. Following several years in the oil patch with Cities Service and Brascan, Bob returned to Vancouver in 1979 to work for Wright Engineers. He subsequently went on to work for Cassiar Mining, Getty Resources and Endeavour Financial before joining Pincock Allen & Holt Ltd. in 1998. His experience ranges from exploration to feasibility studies, financial evaluations of mining and oil & gas projects, due diligence, project finance, valuations and mergers and acquisitions. He has extensive international mining experience pertaining to such countries as Chile, Mexico, Uruguay, Thailand, Indonesia, Angola, Papua New Guinea, Kazakhstan.What are Options?Options have been around for centuries. They were familiar to Roman and Phoenician traders who were shipping cargoes from Mediterranean seaports. In the financial world, options are types of contracts that generally include the right, but not the obligation, to buy or sell a share, currency or commodity. The underlying commodity price or share price changes are assumed to be lognormally distributed. In this context, options are of two general types, ""call"" options and ""put"" options. Call options have the characteristic of having the right to buy a tradable commodity or currency at a predetermined price for a specified period of time. For the owner of call options, they become more valuable as the price of the underlying commodity increases. For the seller of call options, these options become an increasing liability as commodity prices rise, since there is the obligation to sell the commodity at a predetermined (perhaps lower-than-market) price. This characteristic of call options recently became high profile with the sharp rise in gold prices last year. The value of gold call options sold by certain producers increased their associated liabilities to the point where margin calls were made."

Jan 1, 2003

By Tapani Järvinen

Non-ferrous metals and metals in general are considered as being non-renewable natural resources. Metals are needed because of their excellent and irreplaceable properties. The consumption of metals, with the exception of carbon steel, is steadily growing by 1-3 % annually, and that of stainless steel as much as 3-6 %. This is a general trend, which is periodically disturbed by cyclical variations. In recent years so-called "New Economy" has become prominent in the public media and the market value of the traditional industry has been well below its real value and importance. Nevertheless, the modem society requires metals today and also in the future, and the companies using the most modern technology in a responsible way and innovative solutions not only in technology, but also in everything they do will survive. This paper describes the role of Europe as a producer of primary base metals and as a supplier of technologies in the base metals industry. It concentrates on the development and commercialization of technologies and project implementation in the metallurgical industry. As one example ofa European approach to these matters the paper presents Outokumpu's response to the future challenges in the base metals industry. Outokumpu Oyj is one of the leading metals and technology companies in the world of stainless steel, copper, zinc, and sales of technology in metals and minerals businesses. Outokumpu applies its knowledge of metals and processing to generate value for its customers and shareholder. Everything we do, we do in an economically, environmentally and socially responsible way.

Jan 1, 2003

"NI 43-101 is a rule that governs how issuers disclose scientific and technical information about mineral projects to the public in Canada. The disclosure standards apply to oral statements as well as written documents and websites. NI 43-101 does not apply to disclosure concerning petroleum, natural gas, bituminous sands or shales, groundwater, or coal be methane. NI 43-101 first came into force on Feb. 1, 2001 and was revised in December 30, 2005. As a “National Instrument”, the law has been passed in each provincial and territorial legislature across Canada.“PART 1 DEFINITIONS AND INTERPRETATION 1.1 Definitions - In this Instrument “adjacent property” means a property(a) in which the issuer does not have an interest;(b) that has a boundary reasonablyproximate to the propertybeing reported on; and (c) that has geological characteristics similar to those of the property being reported on; “data verification” means the process of confirming that data has been generated withproper procedures, has been accurately transcribed from the original source and is suitable to be used; “development property” means a property that is being prepared for mineral production and for which economic viability has been demonstrated by a feasibility study; “disclosure” means any oralstatement orwritten disclosure made by oron behalf of an issuer and intended to be, orreasonablylikely to be, made available to the public in a jurisdiction of Canada, whether or not filed under securitieslegislation, but does not include written disclosure that is made available to the public only by reason of having been filed with a government or agencyof government pursuant to a requirement of lawother than securities legislation; “early stage exploration property” means a property that has(a) no current mineral resources or mineral reserves defined; and (b) no drilling or trenching proposed; in a technical report being filed in a local jurisdiction; “exploration information” means geological, geophysical, geochemical, sampling, drilling, trenching, analytical testing,assaying, mineralogical, metallurgical and other similar information concerning a particular property that is derived fromactivities undertaken to locate, investigate, define or delineate a mineral prospect or mineral deposit; “feasibility study” means a comprehensive studyof a mineral deposit in which all geological, engineering, legal,operating, economic, social, environmental and other relevant factors are considered in sufficient detail that it could reasonably serve as the basis for a final decision by a financial institution to finance the development of the deposit for mineral production; “historical estimate” means an estimate of mineral resources or mineral reserves prepared prior to February 1, 2001;“IMMM Reporting Code” means the classification system and definitions of mineral resources and mineral reservesapproved by The Institution of Materials, Minerals, and Mining in the United Kingdom, as amended; “JORC Code”means the Australasian Code for Reporting of Mineral Resources and Ore Reserves prepared by the Joint Ore Reserves Committee of the Australasian Institute of Mining and Metallurgy, Australian Institute ofGeoscientists and Mineral Council of Australia, as amended; “mineral project” means any exploration, development or production activity, including a royalty interest or similarinterest in these activities, in respect of diamonds, natural solid inorganic material, or natural solid fossilized organic material including base and precious metals, coal, and industrial minerals;"

Jan 1, 2003

By Fumito Tanaka

The Mitsubishi process is the sole pyrometallurgical process for the continuous production of blister copper from Copper concentrates and has been successfully operated around the world. The development of calcium ferrite slag (CaO-FeOx-Cu10), the so-called "C-slag", has enabled continuous converting from matte to blister copper in the commercial scale operations. Commercial interests in the slag led to many papers over the CaO-FeOx slag. However, Cu2O bearing slag has not been studied well due to experimental difficulties. The authors have quantified the thermodynamic properties of the CaO-FeOX-Cu2O system. The results have been utilized to analyze various issues related to the converting furnace, such as the magnetite precipitation from the slag or from blister copper and to develop better controlling criteria for the continuous converting operation. -

Jan 1, 2003

Mining has traditionally been seen as a relatively risky business. Exploration is expensive and the failure rate is high, while start-up costs commonly run to many hundreds of million dollars. To justify the risk and expense, the returns from successful projects must also be high. Accurate estimation of mineral resources and reserves is fundamental to the processes of optimising returns and managing risk in mining developments. Systematic development from initial exploration through a series of development stages enables expenditure and risk to be balanced. As a consequence, large scale modern mine are more akin to manufacturing businesses. This paper examines the life history of a mineral reserve estimate from the perspective of a large mining company against a background of modern estimation and reporting requirements. It will also touch on what constitutes, in the author's opinion, `best' practice in reserve estimation, and how this concept can be spread more widely. [Abstract to be re-written and reduced to 100 words]

Jan 1, 2003

Limnological processes are often overlooked when trying to assess the long-term water quality of pit lakes. It is essential to deal with these aspects, since they determine the geochemical and redox conditions around the submerged reactive rocks. Underground mining at East Sullivan (northwestern Quebec, Canada) stopped in 1966. Two adjacent stopes, 91 and 106 m deep, were left open to the surface, with roughly circular apertures of about 7700 and 18 000 m2. Water filling of the two glory holes went on over three decades and overflow began in 1999. Surface water pHs values were near neutrality as late as 1994 (6.3 - 7.0) but had become acidic by 1999 (2.6 - 3.5). Limnological processes were investigated in late-1999 and early-2000, with temperature measurements at 1 m intervals and sampling of the water columns before and after the late fall density inversions. A strong chemocline-thermocline was observed at 15 m. Above the chemocline, the water had low pH (3.2), no alkalinity, and low Na, Ca and sulfate. Below the chemocline, the concentrations of these parameters and the pH increased, with pH at 5.5 - 6. Consistent with the low pH values present in the upper 15 m, the concentrations of Al, Cd, Cu, and Zn were high near surface, and decreased below the chemocline. Dissolved oxygen concentrations as well as Eh decreased with increasing depth. Alkalinity integrated over the entire water column below the chemocline was at least six times larger than the acidity inferred from Fe2+ and Fe3+ concentrations. The temperature survey showed that seasonal density inversions do occur in the water column. The inversions do not involve the entire water body, since the surface to depth ratio is too small for a complete overturn. Oxygen from surface waters is carried to the bottom where it oxidises sulfides, until its depletion. Residual Fe2+, stable under anoxic conditions, is displaced upward by the next dense water incursion. It eventually reaches the thermocline, but only after many successive incursions. There, its oxidation to Fe3+ allows hydrolysis, which consumes dissolved and wall-rock alkalinity. It is only in 1999 that alkalinity was finally exhausted and that the pH shifts to acid values. The low pHs in the surface waters allow a build up of Fe3+ and Al3+, and desorption of metals from colloids. Buffering is assumed to be controlled by wall-rock oxyhydroxides in surface waters, and by carbonate minerals in the bottom waters. Because the seasonal overturns are far from being complete, the large amounts of alkalinity acquired from the wall-rock in the bottom waters cannot balance the acidity of near surface waters. Hence the surface water is acidic.

Jan 1, 2003

By Huang Kai

Uniform needle-like and spherical nickel oxalate particles were prepared by the chelating precipitation process, which was based on the reaction of oxalate acid and the solution of ammonia nickel chloride. The molar ratio of ammonia to nickel ion in the mixed solution is essential to determine whether the spherical or needle-like particles are formed, which means actually the concentration of ammonia is the key to determine the growth mechanism. When oxalate acid is added in the form of solid, it may act as the nucleation interface for the eariy-precipitated substance and so induce the formation of spherical particles. The PVP agent can improve the dispersing degree of the needle-like particles and higher reacting temperature leads to larger particles. The composition of the needle-like particle consists of ammonium and nickel oxalate instead of the pure nickel oxalate.

Jan 1, 2003

By D. R. Tesarik, F. M. Jones, J. B. Seymour

As part of safety and stability studies at three underground mines in the United States, researchers installed earth pressure cells and embedment strain gauges in cemented rockfill to measure stress and strain changes as mining progressed and the rockfill was loaded. Data from these instruments were used to calculate the in situ modulus of the rockfill for two of the mines. A three-dimensional numerical model of a cemented rockfill cap was validated with data from extensometers anchored in the mine roof and sill; this model was then used to estimate deformation modulus at the third mine because the earth pressure cells and embedment strain gauges recorded negligible changes. Rockfill binder used at these mines ranged from 4 to 8 per cent of the dry components by weight, the water-to-cement ratio was from 0.42 to1.0, and the largest aggregate size in the three mixes ranged from 5 to12 cm (2 to 4.7 in). The range of the calculated in situ deformation modulus values was large, but as expected, it was bracketed by modulus values for cemented tailings and roller-compacted concrete with similar cement contents and water-to-cement ratios. Dans le cadre d’études sur la sécurité et la stabilité de trois mines souterraines situées aux États-Unis, les chercheurs ont installé des palpeurs de pression des terres et des extensomètres d’encastrement dans les remblais cimentés afin de mesurer les variations relatives à l’effort et à la déformation des terrains durant l’exploitation minière et le chargement du remblai. Les données recueillies à l’aide de ces instruments ont servi au calcul du module in situ du remblai dans deux de ces mines. Le modèle numérique tridimensionnel de la semelle d’un remblai cimenté a été validé à partir des données recueillies par les extensomètres ancrés dans la voûte et dans la semelle de ces mines; ce modèle a ensuite été utilisé pour estimer le module de déformation à la troisième mine, étant donné que les palpeurs de pression des terres et les tensiomètres enfouis avaient relevés des variations négligeables. La matière d’agrégation de l’enrochement utilisée dans ces mines comportait entre 4 % et 8 % des composantes sèches par poids; le rapport eau-ciment se situait entre 0,42 et 1,0; et la taille des agrégats les plus gros dans ces trois mélanges était de 5 cm à 12 cm (2 po à 4,7 po). L’écart entre les valeurs calculées des modules de déformation in situ était grand, mais comme on s’y attendait, cet écart a été compensé par les valeurs modulaires des résidus cimentés et du béton tassé au rouleau avec des teneurs en ciment et des rapports eau-ciment semblables. Als Teil der Sicherheits- und Stabilitätsstudien an drei Bergwerken in den Vereinigten Staaten von Amerika installierten Forscher Erddruckgeber und Einbindungsdehnungsmesser in zementierter Steinschüttung, um Spannungs- und Dehnungsveränderungen während der fortlaufenden Bergarbeiten und der Belastung der Steinschüttung zu messen. Daten von diesen Instrumenten wurden dazu verwendet, das In-Situ-Modul der Steinschüt-ung für zwei Gruben zu berechnen. Ein dreidimensionales numerisches Modell einer zementierten Steinschüttungsschwelle wurde mit den Daten von den im Grubendach und in der Schwelle verankerten Extensometern validiert; dieses Modell wurde dann dazu eingesetzt, um das Deformationsmodul in der dritten Grube zu schätzen, da die Erddruckgeber und Einbindungsdehnungsmesser nur geringfügige Messabweichungen feststellten. Das in diesen Gruben verwendete Steinschüttungsbindemittel variierte zwischen vier und acht Prozent an Trockenkomponenten nach Gewicht, der Wasser-Zementfaktor betrug zwischen 0,42 und 1,0 und die größte Zuschlagstoff-größe in den drei Mischungen schwankte zwischen fünf und zwölf Zentimetern. Die Reichweite der berechneten Werte des In-Situ-Deformationsmoduls fiel etwas breit aus, aber es fand erwartungsgemäß eine Klammerung der Modulwerte zwischen den Zemen-trückständen und dem durch Walzen verdichteten Beton mit ähnlichem Zementanteil und Wasser-Zementfaktor statt.

Jan 1, 2003

By P. K. Naik, S. C. Das

Leaching studies of low-grade manganese ore containing 31.77% Mn and 23.71 % Fe from Nishikhal, India, were carried out using pyritiferous lignite as a reductant in sulfuric acid medium. The variables studied were quantity of lignite, sulfuric acid concentration and temperature. Regression equations for the extraction of manganese and potassium were determined from 23 full factorial design data. The experimental conditions for the extraction of manganese were optimized using the steepest-ascent method. It was found that 99.03% of the manganese could be extracted in three hours with an ore to lignite ratio of 1:1.8, a sulfuric acid concentration of 1.9 M and a temperature of 99°C. Key words: Leaching, Manganese ore, Lignite, Statistical design

Jan 1, 2003

By A. T. Sutaone

"In the Dongri Buzurg Manganese Mine of M/s Manganese Ore (India) Ltd., high grade lumpy manganese ore required for iron and steel industries is produced through multi-stage crushing and screening. This has resulted in accumulation of 50,000 tonnes of low grade fines over the years. This production of such fines is still going on. The fines create environmental problems, like air and water pollution and siltation in adjoining fields. Besides containing lot of manganese values, they occupy large space which is very scare in mining area.The Indian Bureau of Mines under one of its statutory functions has suggested the company to explore the possibility of recovery of additional values under conservation and environmental aspects. Hence the company has sponsored a bulk sample for beneficiation studies in the Modern Mineral Processing Laboratory and Pilot Plant of Indian Bureau of Mines at Nagpur, India. The main manganese minerals present in these mine rejects have been identified as pyrolusite and psilomelane. The purpose of this study was to explore the possibility of evolving a suitable beneficiation flowsheet to obtain manganese concentrates assaying over 72% MnO2 to be used as raw material for the manufacture of dry cell batteries.The sample/material was subjected to characterisation studies in terms of chemical analysis, granulometry and mineralogical compositions. Based on these characterisation studies, the beneficiation process developed comprised of desliming, jigging and low intensity magnetic separation mainly to reject quartz, silicates and jacobsite. The manganese concentrate thus produced assayed 70.2% MnO2 with MnO2 recovery of 78% and weight per cent yield of 63.5. This natural concentrate could be mixed with the electrolytic manganese dioxide produced by the company and this blend can thus be used as a raw material for the manufacture of dry cell batteries by the end users. The paper deals with the details of test work carried out in evolving the process flowsheet."

Jan 1, 2003

By S. Jeon, J. Kim, H. Lee

Though the importance of the engineering rock mass properties such as deformation modulus, cohesion and friction angle is emphasized, the researches on the reliability of these values are rarely performed. By using modified Takagi-Sugeno (TS) fuzzy inference system, a fuzzy model was developed based on the data obtained from domestic tunnel construction sites, and the ability of prediction was compared with the empirical equations conveniently used for estimating these values, which finds that fuzzy model is better than empirical equation. Sufficiently large database, however, is required for training the fuzzy model for more accurate prediction. Obwohl die Wichtigkeit der technischen Eigentümer der Felsenmassen wie zum Beispiel Verformungsmodulus, Bindekraft und Reibungswinkel betont werden, wird die Forschung auf der Zuverläßigkeit dieser Werte selten durchgeführt. Mit modifiziertem Takagi Sugenos (TS) Flaumigenschlußsystem wird die Flaumigenmodelle von den Daten, die von inländischen Tunnelbaustellen erhalten werden, entwickelt. Zum Schätzen dieser Werte ist es viel günstig, Flaumigenmodell zu benutzen, als zu adoptieren die empirische Gleichung für die Fähigkeit der Voraussage. Genügende große Datenbank wird aber zum Ausbilden flaumigen Modells für genauere Voraussage erfordert. Quoique l'importance sur la caractéristique d'ingénierie de la masse de roche comme le module de déformation, la cohésion et l'angle de friction, soit soulignée, la recherche sur la confiance de ces valeurs est rarement effectuée. Avec le système modifié de Takagi-Sugeno(TS) fuzzy inférence, le nouveau modèle fuzzy s'est développé. Après avoir estimé sa valeur, nous pouvons savoir que ce modèle fuzzy, basé sur les données venant du chantier de construction de tunnel national, est mieux que l'équaton empirique. Pourtant plus de données de base sont indispensables pour produire le modèle fuzzy plus précis.

Jan 1, 2003