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By Ronald F. Balazik

This Bureau of Mines study identifies and examines the costs of Federal, State, and local environmental protection controls on domestic phosphate rock mining, The costs include the expenditures needed to comply with government regulations and the effects that these expenditures and regulations have on supply. The study analyzes costs of environmental impact assessments, air and water quality standards, reclamation laws, potential solid waste controls, and local government restrictions. In addition, an industry survey and the Bureau's Minerals Availability System (MAS) are used to evaluate land management policies that restrict access to phosphate resources, Conclusions drawn from these analyses confirm that (1) domestic phosphate mining has incurred substantial control costs and may be subject to significant new regulatory costs in the next several years, (2) certain environmental controls can discourage mining investment, (3) environmental policies governing land-use controls affect the disposition of sizable phosphate resources, and are key determinants in the development of those resources on the Federal do- main, and (4) environmental costs could diminish the competitiveness of domestic producers.

Jan 1, 1983

By William B. Hughes

The rubber-sleeve core barrel was developed to improve core recovery from unconsolidated sands, where it is most difficult to obtain cores with conventional barrels. The use of a rubber-sleeve core retainer, together with other departures from clsual design, has required a considerable amount of testing to prove its op-erability. Tests run in shallow experimental holes and in drilling wells in the U. S. and Vemzuela have, to a large extent, proved the operation of the barrel. Internal mechanism troubles, such as sandbinding of the sleeve, have been largely overcome. Cores have been recovered from completely unconsolidated sands where conventional coring has almost been abandoned because of poor recovery. In addition to retaining the core until brought to the surface, the barrel gives a "packaged-ar-cut" core, which is coilverzient for handling and transportatiorz. In the initial work, drag blade cutters, roller cutters, and tungsten carbide insert cutters were usrd for cutting unconsolidated sands. Further bit head development is presently being conducted using diamond heads in unconsolidated sands where shaler, hard sands, and limestones are encountered in adjacent formations. Thir work should render the barrel capable of cratting and recovering most types of formations, possibly including broken and frac- tured fornlations. This development is being carried on in cooperation with a diamond bit manufacturer. INTRODUCTIO N For many years the oil industry has needed greater recovery of cores from unconsolidated formations. Conventional equipment has been used to core unconsolidated sands with little success. Specifically, a core barrel was needed which would recover unconsolidated sands in a condition that would give useful reservoir information. DEVELOPMENT OF 'THE RUBBER-SLEEVE CORE BARREL Basic Requirements of Unconsolidated Sand Corino The basic need was defined as a core barrel that would obtain a continuous unconsolidated core with sand grains in place as deposited in the formation. A preliminary survey of coring equipment and search of the literature pointed out the weaknesses of conventional core barrels. Laboratory tests using unconsolidated sand in a metal tube simulated actual sand movement into the core barrel during conventional coring. In conventional barrels the core sometimes crumbles and bridges, or fails under compressive column action, becomes oversize, and wedges against the walls of the inner barrel. The core barrel requirements established by the surveys and preliminary tests are as follows. 1. The core should be held to- gether as it is cut so it cannot crumble and bridge against the walls of the coring tool, care being taken not to permit damage from fluid circulation. 2. The core should be continuously supported as it is cut so it will not have to support itself in compression. 3. The core should be packaged in the barrel to retain an undisturbed condition during the trip out of the well. The packaging should be such that the core can be removed from the barrel and shipped to the core analysis laboratory without physical disturbance or alteration of fluid content by exposure to the atmosphere. Operation of the Rubber-Sleeve Core Barrel The rubber-sleeve core barrel (Fig. 1) meets the basic requirements for the recovery of unconsolidated sands.

By A. Butler

This paper explains the politics of mine nationalization in contemporary South Africa. Nationalization and privatization typically occur in the oil, mineral resources, and state utilities sectors, and they tend to follow one another in a long-term cyclical pattern. The paper explains why the current international environment has encouraged demands for nationalization and other forms of ?resource nationalism? in the South African minerals sector. It goes on to describe how the resurgence of resource nationalism has been influenced by internal factional politics in the African National Congress. It concludes that nationalization is unlikely to be the outcome of current policy deliberations within the ANC.

Jan 1, 2013

By P. Kobylin, K. Haavanlammi, K. Valkama

"Base metals and precious metals can be recovered from a nickel matte or nickel concentrate using the Outotec nickel chloride leaching process. The raw material is leached with hydrochloric acid and the metals are recovered by solvent extraction, where ammonia is used to control the pH. Ammonium chloride is regenerated to ammonia and the side product of this step is calcium chloride solution. The regeneration utilizes either calcium oxide or calcium hydroxide. The calcium chloride solution is used to convert sulfuric acid into a hydrochloric acid solution while producing pure gypsum as a side product. The regeneration and reuse of ammonia and hydrochloric acid in this process will have a positive impact, from the point of view of both operating costs and environmental sustainability. This paper concentrates on the test work and technical concept development performed by Outotec to implement and develop chemical regeneration and recycling into a vital part of the nickel chloride leaching process.INTRODUCTION According to a nickel market analysis, the nickel market is expected to grow in the future. Main driver for this growth is the increase in stainless steel consumption as the living standards are equalizing globally. The expected increase in the amount of electrical cars and the need for nickel in the batteries of electrical cars also gives potential for the increased need for nickel in near future. At the moment the use of nickel in nickel-cobalt-manganese (NCM) and nickel-cobalt-aluminium (NCA) Li-ion batteries is in the range of 14 ktpa. It is estimated to increase to the level of 90 ktpa by 2025. In every era of the nickel industry, Outotec has been constantly developing new processes to create environmentally sustainable and economically viable processing routes. The Outotec® Nickel Matte Chloride Leaching process is a great example of a process that is flexible regarding raw material and could also treat nickel raw materials that are difficult for smelters. Outotec’s main options for pyrometallurgical nickel treatment include the Outotec® Direct Nickel Flash Smelting process (DON) and the Outotec® Ausmelt TSL process. The DON process is operated in Boliden Harjavalta Nickel Smelter in Finland. Ausmelt process is in use for example in Daye nonferrous plant in China. In the Outotec® Direct Nickel Flash Smelting Process, a sulphide nickel concentrate is processed in an Outotec Flash Smelting Furnace (FSF). Producing concentrates and processing them by Outotec Direct Nickel Flash Smelting to matte followed by hydrometallurgical refining offers a reliable route from concentrate to product. In the DON process, high-grade matte with low Fe content is produced in the FSF and the valuable metals in the slag are recovered in an electric furnace (EF). The Outotec® Ausmelt TSL process can use a large variety of raw materials (concentrates, secondary material and scrap metal) as feed. Fuel and oxygen are injected into the furnace through TSL (Top Submerged Lance) and this enables efficient smelting. Both Flash Smelting and TSL plants produce nickel mattes, which can be refined with Outotec hydrometallurgical processes."

Jan 1, 2017

By Richard Quirk

This report describes methods and techniques employed by The Glidden Co. of Cleveland, Ohio, in explorating an ilmenite-bearing sand deposit in Ocean County, New Jersey, during 1960 to determine ore reserve potential and the feasibility of mining and establishing a milling plant on the property for the production of ilmenite concentrate. The property covered approximately 1,250 acres. Comprehensive sampling by water-jet drilling indicated the deposit averaged 20 feet in thickness and contained 4.5 percent heavy minerals, of which 80 to 85 percent was ilmenite and leucoxene. Average depth of the water table as determined by auger boring was 16.8 feet. Pilot plant tests indicated that circular concentrators in combination with spiral concentrators would recover at least 80 percent of the heavy mineral content of the sands. It was estimated that sufficient ore reserve tonnage had been developed to supply the company's Baltimore chemicals division, pigments department, with a suitable grade ilmenite concentrate for a period of 20 years at the present rate of pigments production. The property was designated as Lakehurst mine and plans are in progress for mining development and plant construction.

Jan 1, 1963

By P. C. McWilliams

Researchers at the U.S. Bureau of Mines investigated the use of close-range photogrammetry and subsequent stereo digitizing to obtain data from rock fracture roughness profiles. The photogrammetric process yielded results that were acceptable but somewhat inferior to those obtained by a mechanical profilometer. On the basis of this study, further pursuit of photogrammetry as a data collection method in mining is proposed. Fractal geometry was investigated as a means of measuring the roughness of rock fracture profiles. Four fractal algorithms were used: divider method, modified divider method, box method, and spectral method. A comparison of the methods gave ambiguous results. Brown's modified divider method provided the best means of obtaining the fractal dimension. Shear strength estimates were obtained using the parameters of the modified divider method and Myers' Z2 measure. Because of differences in results when comparing the different ways of obtaining the fractal dimension, future users of fractals in studies of rock fractures are advised to cross-check their results carefully.

Jan 1, 2010

Regions with extensive reserves of brown coal but with inadequate deposits of hard coal provide a particularly suitable field for the application of brown coal petrology.In fact, this discipline is indispensable where brown coal is to form the basis for high-quality products of upgrading. Both chemical and physical analyses are required in addition to the techniques employed in coal petrology, but it is the macropetrographic and the microscopic investigations that are of decisive and specific importance.Foremost among the methods of upgrading brown coal is briquetting. From the raw materials aspect the biochemical rank of coal (i.e. the type of deposit) and the coal variety (i.e. the lithotype) exert a marked influence on briquette strength. These are also the significant factors in the suitability of a brown coal for high temperature carbonization; here the demands on coal quality are even more exacting if adequately sintered and therefore high-strength lump chars are to be obtained. The principle applies also to the char from low temperature carbonization. There are close relationships between the tar yield and the remission of the coal.The reflectivity measurement therefore provides a rapid method for evaluating the suitability of a brown coal for low temperature carbonization. Similar correlations have been established between the content of extraction bitumen (raw montan wax) and the remission. Petrological investigations show that the quality of the coal bitumen is a function of the type of deposit and of the lithotype.

Jan 1, 1968

By D. A. Dukelow, K. Li, G. C. Smith

Decarburization in the Fe-C system by oxygen top blowing has been studied in laboratory -scale experiments. It is shown that equilibrium models fail to explain or predict either the course of refining or endpoint conditions, giving results which either are incompatible with the chemistry of the system or do not satisfy material balance requirements. Also the path of decarburization was found to vary even for heats made under apparently identica1 conditions. A promising approach to analyzing the decarburization results is to relate oxygen efficiency fm carbon removal to bath carbon content. This relationship for Fe-C heats shows the same range of oxygen efficiencies as is obtained in pilot-plant and commercial heats using hot metal-scrap charges. This implies that oxygen transfer is primarily controlled by the decarburization reaction itself, independent of other refining reactions. Therefore, it should be possible to study separately decarburization and slag-metal reactions. DECARBURIZATION is probably the most important reaction in steelmaking. Not only is it a main reaction in the refining of iron to steel but it also provides the stirring action in the bath necessary for the diffusion processes to proceed at reasonable rates so as to make a steelmaking process practical. Kinetics of decarburization in the open-hearth process has been a subject of investigation for many years.&apos;-B It is generally accepted that at steelmaking temperatures the rate of homogeneous C-0 reaction is extremely high and cannot constitute a rate-controlling step. Diffusion of oxygen through a boundary film in the metal phase has been suggested by arken&apos; as rate-determining. Recently, Larsen and sordah16 concluded from experiments in a laboratory furnace that, with oxygen supplied from air or combustion gases, the rate of "steady-state" carbon boil is controlled essentially by a diffusion process of O2, Co2, or H2O through a film of nitrogen above the slag surface. Displacing this diffusion film by a stream of nearly pure oxygen produced a ten-fold increase in the rate of carbon boil with the rates of slag-metal oxygen transfer, bubble nucle-ation, and other steps all apparently able to keep pace. In the top-blown basic oxygen process, however, the transport of oxygen takes a more direct route. and the state of bath agitation is much more turbulent than in the open-hearth process. In addition, direct contact of the gas with the metal phase provides opportunity for direct oxidation of carbon. It is likely that the rate-limiting factor for the decarburization reaction will be different. However, only a few descriptive discussions of the subject have been reported in the literature.10-l2 Studies of the decarburization kinetics based on plant or pilot-plant data are necessarily complicated and are influenced by other refining reactions which occur simultaneously. In order to investigate the mechanism of decarburization, experiments have been conducted in which carbon-saturated iron melts were top-blown with pure oxygen over a range of conditions. It is hoped that this study will form a foundation on which a more basic understanding of this important reaction may be built. EXPERIMENTS One group of blowing experiments was made in a standard 200-lb induction furnace and another group in a 500-lb induction furnace. The furnaces were modified to the general shape of a basic oxygen furnace by adding a rammed refractory cone section to the regular crucible body. Crucible and cone were of high MgO (95 pct) material. A water-cooled lance, 1/2 in. in diam and threaded at one end to take a nozzle, was used for blowing oxygen. The lance with its water and oxygen lines was supported on a cantilever arrangement so that it could be moved up, down, or sideways. Oxygen of 99.5 pct purity was supplied from a cylinder and metered through a rotameter equipped with pressure and temperature gages. Another pressure gage was located at the top of the lance. A schematic diagram of the assembly is shown in Fig. 1. Before each experiment, a weighed amount of ingot iron, containing 0.02 pct C, < 0.01 pct Si, 0.10 pct Mn, 0.019 pct P, and 0.015 pct S, was charged in the furnace and melted down by induction heating. Graphite was then added to the molten charge until it became saturated. When the temperature of the charge reached the desired level, the lance was lowered to a predetermined height above the bath

Jan 1, 1964

By E. H. Jr. Dix

A LACK of experimental data illustrating the effect of composition, particularly in respect to impurities, on the mechanical properties and corrosion resistance of aluminum-alloy die castings induced the authors and their associates to undertake a limited study of these relations. A number of commercial alloys .and several experimental variations of a commercial alloy were used for the investigation. Mechanical property, growth, steam, paraffin, salt spray and atmospheric exposure tests were employed. This paper deals with the more accelerated tests and the results they have produced. It is concluded that a high-silicon alloy with all impurities except iron strictly limited to small amounts will develop an excellent resistance to corrosion and retain satisfactory mechanical properties and casting characteristics. As a direct result of this investiga-tion an alloy of this character with superior corrosion resistance is now available commercially. In general, copper increases the strength and decreases the elongation and corrosion resistance. Tin reduces the mechanical properties and the resistance to corrosion. Iron reduces the elongation and, if excessively high, may adversely affect the tensile strength. Even excessively high iron contents do not affect the corrosion resistance, which is fortunate for the die caster as it is this element that is the most difficult to control. Nickel and zinc in limited amounts do not seem to affect the properties or corrosion resistance of at least the high-silicon alloy. Growth tests have confirmed the previous common belief that dimensional changes under either dry or wet conditions at 100° C. are too small to be of practical importance.

Jan 1, 1935

By Owen Matthews

Introduction For the past year and a half, the mill of Cochenour Willans Gold Mines, Limited, McKenzie Island, Ontario has been roasting arsenopyrite-gold concentrates, prior to cyanidation, by means of a roaster employing techniques that are new and novel. The roaster is known as the Dorrco &apos;fluo-solids reactor&apos;, and the technique as &apos;fluidization&apos;. The reactor has demonstrated its ability to roast a flotation concentrate containing arsenopyrite, pyrite, stibnite, small quantities of other sulphides, and some lime silicates and carbonates, yielding a calcine consisting mainly of porous iron oxide, plus the gold values. This calcine is readily amenable to cyanidation. Bulk shipments of concentrates to a distant custom smelter, as practised prior to this installation, has thus been eliminated, with appreciable savings in smelting charges, freight costs, and interest losses during shipment and smelting. This is the pioneer installation of fluo-solids roasting at a Canadian mill and up to the present performance results have not been published. It is the purpose of this paper to present the information now available for the benefit of other millmen who may be confronted with identical or similar problems to those encountered and solved at Cochenour Willans.

Jan 1, 1949

By Warren Hastings

This paper describes the methods and costs, in units of labor end materials, of sinking a 7 compartment vertical shaft 1,261 feet through a fractured, water-saturated formation. The shaft, designed for hoisting 2,500 tons a day, is at Friedensville, Lehigh County, Pa., approximately 6 miles south of Allentown and Bethlehem. It was sunk by the E. J. Longyear Co. under contract to the New Jersey Zinc Co. Preparation for shaft sinking W8A begun July 1, 1947, and sinking was completed August 18, 1952. A total of 604,858 man hours was required to sink the shaft.

Jan 1, 1954

The general nature of the special constructional features that are required to provide safety from explosion hazards on machines approved as permissible by the Bureau of Mines is fairly well known to mining men who are at all interested in safety. These requirements are outlined in the schedules under the provisions of which the investigations of such machines are conducted. Also, the method of conducting inspections and tests of such machines has been described in Bureau of Mines Bulletin 305, Inspection and Testing of Mine Type Electrical Equipment for Permissibility, published in 1929. A more detailed knowledge of the special safety features of a particular machine is often useful and sometimes essential for inspectors, safety engineers, maintenance men, and engineers in selecting machines for a particular application. Three bulletins that give information of this nature have been-published by the bureau, viz., Bulletin 313, Permissible Storage-Battery Locomotives and Power Trucks. Bulletin 343, Permissible Coal-Handling Equipment. Bulletin 382, Permissible Coal-Cutting Equipment. Report of Investigations 3309, Permissible Electrically Operated Air Compressors, which contains similar information, was issued in August 1936, and a Report of Investigations 3326, Permissible Electrically Operated Room Hoists, was issued in January 1937. Thus, the present paper is the third to give detailed information concerning permissible machines of types not included in bulletins, and covers all the rock-dust distributors approved prior to October 1, 1936.

Jan 1, 1937

NEW MEMBERS The following list comprises the names of those persons who became members during the period July 10 to Aug. 10, 1915: Members ALBERTSON, MAURICE MERTON, Mine Surveyor, Mining Corporation of Canada, Cobalt, Ont., Canada. ARMSTRONG, GEORGE CHANDLER Mgr., Indian Refining Co., Lawrenceville, Ill. BARBER, MAX HAYDEN, Min. Engr Supt., Crosby Mine, Nashwauk, Minn. BARNESON, JOHN Merchant, 310 Sansome St., San Francisco, Cal. BENSEL, JOHN A., Cons. Engr 111 Broadway, New York, N. Y . BORGESON, ANSHELM CYRUS, fin. Engr Shenango Mule, Chisholm, Minn. BROOKS, CHARLES PETER, Min. Engr 228 Dooly Bldg., Salt, Lake City, Utah. BROWN, FRANK HAROLD, U&apos;011&apos;,. Min. Engr., Federal Co., Inc., 50 Broad St., New York, N. Y. CLARK, DOUGLAS Kellogg, Idaho.

Jan 9, 1915

By Jonathan Peck, Doug Pollitt, Malcolm Scoble

Over the past 5 years the Department of Mining and Metallurgical Engineering, McGill University, has been involved in the performance monitoring of both percussive and rotary drills. Studies conducted in open pit coal and iron ore mines using microprocessor-based research and commercially available instrumentation resulted in the monitoring of at least 6 performance parameters while drilling vertical production blastholes.

Jan 1, 1991

By Todd M. Ruff

The majority of fatalities that occur in road construction work zones in the United States involve a worker being struck by a piece of construction equipment or other vehicle. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health, in cooperation with the Washington State Department of Transportation, is evaluating methods to decrease these accidents. One such method uses devices that assist equipment operators in monitoring blind areas around the equipment to prevent collisions with workers on foot or other objects. Several cameras and sensor systems are available for this application, and a study was conducted to evaluate these systems on various trucks used in road construction and maintenance. Tests were conducted using sanding trucks during the winter months, which allowed researchers to investigate the effectiveness and limitations of various technologies under the most extreme conditions. Tests were also conducted using dump trucks during the warmer months to study the effectiveness of the systems in highway work zones. Results show that many difficulties arise when using camera and sensor systems in cold, snowy climates. And, while the operation of these systems is more reliable during the warmer months, challenges still exist in using them on equipment in crowded work areas.

Jan 1, 2004

By Dipak C. Talapatra

This report describes the development of guidelines for design, inspection and maintenance of automatic couplers. In order to devise the guidelines, performance requirements for automatic couplers were carefully established. This was done through a comprehensive survey of coupler manufacturers and extensive observation of automatic couplers in service in a broad spectrum of mines. The capability of the couplers to withstand the demands of the mining environment in terms of strength characteristics, gathering range, curve negotiability, and other factors were all carefully evaluated. An analysis of coupler related accidents for the years 1972-1976 was carried out to provide information on the safety and reliability of existing automatic couplers. This formed an important input to the development of the guidelines. It is expected that these guidelines will be useful to coupler manufacturers for establishing designs for improved automatic couplers, and to mine operators for maintaining their couplers in a safe and good operating condition throughout their expected lifetime. This report is in two volumes: Volume 1 Technical Report Volume 2 Design, Inspection, and Maintenance Manual

Jan 1, 1977

By G. W. Jones

In a previous report,6 results were given that showed the amount of natural ventilation in a manhole having a capacity of 74.l cubic feet when the number of ventilation openings in the cover was varied. from no openings to a maximum of 48. The results showed that the ventilation (air changes per day) in the manhole was proportional to the area of the openings in the cover, and also that the number or area of the openings was the factor that chiefly affected the ventilation.

Jan 1, 1937

By Hon-Yim Ko

The properties of coal from the Pittsburgh seam, procured from the Bruceton and Federal No. 2 Mines were found to be similar. Strength and stiffness properties of Beehive Mine coal were determined and the material found to be isotropic. Mechanical, index and geologic properties of roof and floor coal measure rocks from Beehive mines were measured and correlated. Analytic formulations are given for coal creep under uniaxial loading, while triaxial creep is being investigated. Results of testing of coal model structures are compared with predictions from using several material models.

Jan 1, 1976

By J. Xiao, Y. Jiang, Y. Tanabashi, Z. Song

Modelling the effect of blasting-caused damage, anisotropy of rock masses and excavation sequence on deformational behaviour and stability of large-scale underground caverns is important in the design and information-oriented construction of the pumped storage power plant. A powerful three-dimensional numerical method that can be applied for that purpose is presented in this paper. Damaged range caused by blasting and mechanical properties of rock masses near to the walls of caverns are determined by using the back analysis approach in which three lines of the measurement results during the arch part excavation process were used to verified the simulations. Finally, applying the improved model and properties of rocks, the cavern stability and reinforcement effect of the preliminarily designed support system are also estimated for the safety in the bench excavation process. La création de modèles des effets relatifs aux dommages résultant des explosions, à l’anisotropie des masses rocheuses et à la séquence d’excavation quant au comportement à la déformation et à la stabilité des cavernes souterraines de grandes dimensions est une étape importante dans l’étude et la construction sur ordinateur de centrales hydrauliques à accumulation par pompage. Cet article traite d’une méthode numérique tri-dimensionnelle puissante applicable à cet effet. La gravité des dommages résultant des explosions et les propriétés mécaniques des roches à proximité des parois de la caverne sont déterminées par une analyse du fond dans laquelle les simulations sont vérifiées à l’aide de trois lignes de résultats de mesures prises durant le processus d’excavation de la partie arche. Finalement, la stabilité de la caverne et les effets du renforcement du système de support préalablement conçu sont estimés par application du modèle amélioré et des propriétés de la roche, pour application à la sécurité durant le processus d’excavation en gradins. Nachahmung der Wirkungen von durch Explosionen hervorgerufenen Schäden, Anisotropie der Gesteinsmassen und der Ausschachtungssequenz auf das Verformungsverhalten und die Stabilität großräumiger Untergrundhöhlen ist für das Design und den informationsorientierten Bau von Pumpenkraftwerken wichtig. Entsprechend der Vorgaben in dieser Arbeit kann ein leistungsfähiges, dreidimensionales numerisches Verfahren für diesen Zweck eingesetzt werden. Der durch Explosionen und die mechanischen Eigenschaften des Gesteins bedingte Schadensumfang im Bereich der Höhlenwände kann mit Hilfe eines retroversen Analyseansatzes bestimmt werden, bei dem die drei bei der Ausschachtung resultierenden Messlinien dazu genutzt wurden, die Simulationen zu bestätigen. Abschließend wurde außerdem durch Einsatz verbesserter Modelle und Gesteinseigenschaften die Auswirkungen vorläufig entworfener Unterstützungssystem auf die Höhlenstabilität und Verstärkungswirkungen hinsichtlich der Sicherheit bei Böschungsausschachtung abgeschätzt.

Jan 1, 2003

By Varadarajan Seshadri

Geometallurgical characterization of iron ore which is a raw material for Iron making as in the case of charcoal blast furnaces operating in Brazil or for production of agglomerates such as iron ore sinter which serves as burden material for blast furnces of high productivity or pellets extensively used in the direct reduction processes all over the world in the iron and steel industry. Selection of proper raw material after due characterization should lead to an improvement of the productivity of the respective processes The usual classification of quality of iron ore is uniquely based on chemical analysis, granulometric and physical parameters. However not much emphasis has been given to the structural characteristics which also are important in the processes. Different typological categories of Brazilian iron ores have been used in the characterization . For instance, several kinds of hematite crystals like specularite, martite and microgranular hematite, etc with variable crystal sizes are found in the different ore types. They are also composed of different of fabrics and types of accessorial mineralogical constituents and have different porosities, pore diameters, etc which influence the cold and the hot agglomeration stages of the ore fines, and also chracteristics such as reducibility, decrepitation etc, important for assessment of quality of iron ores. . The first step for attaining a good characterization of ores is to know in detail about the structure of the deposit, shape of the body, types of iron ores and their distribution. This requires a geological-structural study and the mapping of the bodies using mineralogical criteria for typological classification of ores. followed by structural characterization of materials in stages of mining, comminution, screening and concentration processes. In this contribution a geometallurgical approach for quality control of Brazilian iron ores for sintering and pelletizing processes is highligted.

Jan 1, 2006