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By X Hu, C-C Yang, J Pan

In this work, preheating and roasting tests of pellets made from blends of Western Australia ultra-fine (WAU) magnetite concentrate and Chinese domestic magnetite concentrate or Brazilian hematite concentrate were carried out. The results showed that pellets made from 100 per cent WAU magnetite concentrate possesses inferior preheating and roasting performance when preheating at 1050°C for 20 minutes and roasting at 1300°C for 40 minutes, the compressive strength of preheated and fired pellets is 502 N/pellet and 2313 N/pellet, respectively. When 40 per cent Chinese domestic magnetite concentrate or 20 per cent Brazilian hematite concentrate was blended with 60 per cent or 80 per cent WAU magnetite concentrate, the appropriate preheating temperature of the pellets are reduced from 1050°C to 950°C and 975°C, and also the firing temperature of two types pellets are decreased from 1300°C to 1250°C and 1280°C respectively. Moreover, the compressive strength of fired pellets is obviously improved up to 2746 N/pellet and 2630 N/pellet respectively. Microstructure analysis of the fired pellets made from 100 per cent WAU shows its poor growth of Fe2O3 grains, low interlinkage degree of hematite grains, small size of crystallised grains and high porosity of pellet; however, the fired pellets that blended with domestic magnetite concentrate or with Brazilian hematite concentrate have fully growth of Fe2O3 grains, closer interlinkage of hematite grains, lower porosity and stronger consolidation. The preheating and roasting performance of WAU magnetite concentrate pellets can be improved by optimising ore matching.CITATION:Pan, J, Hu, X, Zhu, D-Q and Yang, C-C, 2017. Pelletising performance of Western Australian ultra-fine magnetite concentrate and strengthening technique by optimising ore matching, in Proceedings Iron Ore 2017, pp 97–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Ana E. Bohé, Georgina De Micco, Juan P. Gaviría, FEDERICO J. POMIRO, Gastón G. Fouga

Chlorination and carbochlorination processes have industrial applications in metallurgical activity for extraction and purification of uncommon metals such as rare earth elements (REE). This study reviews the chlorination and carbochlorination reactions of light REE (LREE) oxides with chlorine considering the thermodynamic, stoichiometric, and kinetic aspects of the reactions. Lanthanides between lanthanum to gadolinium were considered as LREE, in agreement with previous literature, and the results were detailed in this review. LREE were analyzed taking into account their oxidation states and were divided into three groups accordingly. The results presented show that, although the LREE are chemically similar, their behaviors during the reactions with Cl2 and Cl2–C, and the different LREE-O–Cl compounds formed, have particularities. It was observed that gadolinium, in both thermodynamic calculations and experimental results, presents some differences, and it can be considered intermediate between light and heavy REE; i.e., reactions between LREE2O3 and Cl2(g) begin at approximately 250 °C, except for Gd2O3 that begins at 327 °C. The present work will contribute to a better understanding of the chemistry of LREE oxides and Cl2 under different conditions and the products obtained in the LREE–O––Cl2(g) and LREE–O–C–Cl2(g) systems.

Oct 15, 2021

By K. E. Harrison

The acid rain legislation has passed into law. This new law has caused the power generation community to investigate alternative methods to obtain compliance with the new legislation. One thing all of the power companies have concluded is the answer is not easy. Do we switch fuels to burn all low sulfur compliance coal? Maybe possibly only partial desulfurization by means of a dry sorbent system? Or, finally, maybe a wet scrubber system? Whatever the choice, the power community needs to investigate all of the alternatives. In 1988, ICF Kaiser Engineers, Inc. (ICF KE) responded to a request by the U.S. Department of Energy for the engineering development of advanced physical fine coal cleaning. ICF KE responded and was awarded a contract to conduct a multi-task program to develop an advanced flotation system to eliminate pyritic sulfur and retain as much energy as possible. ICF KE assembled a team that included members of industry, academia, and industry research organizations to conduct this multi-task program. The program includes sixteen (16) tasks. This team had personnel to help solve some of the anticipated problems and to provide industry prospective on the viability and commercial potential for any concepts proposed. The primary team consists of a major coal producer, Babcock and Wilcox, Eimco Process Equipment Company, and Virginia Polytechnic Institute and State University.

Jan 1, 1992

By Eder Salazar

Como parte del desarrollo de sus operaciones de mina de cobre subterránea, la Sociedad Minera El Brocal S.A., desarrolló el método de minado tajeo por subniveles con pilares recorridas con el fin de incrementar su producción actual. En ese sentido, el presente texto señala la implementación de un método de minado conforme a las características geomecánicas del macizo rocoso del yacimiento.

Sep 12, 2011

By H. H. Dreissen, F. J. Fontein

The operating principle of the classifying cyclone has been described often but some special aspects of the cyclone receive further clarification here. In addition, several uses of the classifiers are summarized and made clear by means of practical examples. In coal and ore washeries, the washing cyclone is widely used for the separation by specific gravity of sizes up to about 12 mm. This application has lately been extended to the separation by specific gravity of particles up to about 50 mm. This use makes special demands on the construction and wear resistance of the cyclone. The sieve bend, a development of the Dutch State Mines which is less well known than the hydrocy-clone, is dealt with at some length. The sieve bend is an apparatus designed for wet screening. Attention is given to the variables influencing the performance of the sieve bend. Hydrocyclones are now so widely applied that it would be difficult to find an industry not, directly or indirectly, using them or knowing how to use them since publications on this subject abound.1-3,5,9-11,13-15 However, because of the large number of variables influencing the operation of classifying cyclones, it is not entirely possible to calculate the results of this type of cyclone. Therefore, a number of lesser known variables will be discussed here along with some special applications of the classifying cyclone. FACTORS INFLUENCING CYCLONE CLASSIFICATION Shape of Particles: The shape of particles may cause a much coarser classification than the one expected, considering the sieve analysis and the cyclone dimensions chosen. This was clearly shown by feeding a mixture of spheres and disks in water into a cyclone. The spheres were 0.36 mm diam and the disks, 3 mm diam and 0.03 mm thick. These dimensions were chosen in order that the disks and spheres might have the same rates of fall under gravity. Both spheres and disks had a specific gravity of 1.05. The results obtained with these particles in a cyclone are summarized in Table I. Test No. 2 shows that the catch of spheres was

Jan 1, 1963

It has been fairly firmly established (Fisher, N. H., 1945) that the fineness of the gold in any ore deposit varies with the depth from the surface at which the deposit was formed, and, as a corollary to this, that it is dependent upon the temperature and pressure at the time of deposition. This relationship is such that, under certain conditions, the gold fineness, taken into consideration with other recognised criteria, furnishes a very sensitive and reliable guide to the relative temperature of ore formation, at least within the epithermal and the upper part of the mesothermal range.Definition of Fineness.The fineness of gold is calculated in parts per thousand and refers to the proportion of gold present in the naturally occurring metal in the lode, which is actually a gold-silver alloy, containing usually about 10 parts per thousand of base metal and up to 500 parts perthousand of silver. A clear distinction should be made between fineness and gold-silver ratio. The latter refers to the total gold and silver in the lode as determined by assay and is usually expressed as the ratio Au:Ag. Only in deposits where other silver-bearingminerals are entirely absent, which occurs comparatively rarely, can the gold-silver ratio be used as a measure of gold fineness and, in many cases, the two have no relationship. For instance, in the Edie Creek area in New Guinea, the lodes formed under shallow epithermal conditions all carry gold 500 to 550 fine, although the gold-silver ratio ranges from 1:100 to 1:1, in places in adjacent lodes.Determination of Gold Fineness.The fineness of lode gold can be determined only after it has been separated from all other minerals. Amalgamation recovers gold fairly cleanly - unless native silver is present - and the fineness of amalgam bullion is generally a reliable indication of the correct fineness of the gold. If the use of plates is involved, the bullion may be adulterated, but the effect of any copper, or other metal, that may have been introduced can be cancelled by assuming that the gold and silver shouJrl add up to about 990 fine, or by ignoring the base metal content altogether, which varies little in naturally-occurring gold, and in calculating for comparison purposes all fineness figures to the basis Au + Ag = 1,000.The composition of bullion obtained from cyanidation is generally intermediate between the true gold fineness and the total gold-silver proportion as determined by assay of mine or mill-head samples of Cyanide solution dissolves other silver-bearing minerals and the fineness of the resulting bullion is thereby lowered. Consequently, the fineness of cyanide bullion rarely corresponds to the true gold fineness and is useless for diagnostic purposes, although it is a common fallacy to refer to the fineness of cyanide bullion as the fineness of the gold.

Jan 1, 1950

By T S. Giraudo

The Macraes Gold Project, operated by GRD Macraes Limited, engaged GRD Minproc Limited to assist with the evaluation of a pressure oxidation circuit, this being the key component of a recovery enhancement project. The initial study gave sufficient confidence in the process to enter into project execution. GRD Macraes Limited was the first company to license Newmont Mining Corporation's pressure oxidation technology, which aims to improve gold recovery from the carbonaceous sulfidic flotation concentrate. This paper outlines the fundamental chemistry of the process followed by a description of the plant that was ultimately installed. A summary of the commissioning is given together with an overview of the production results to date. The project ramp-up was rapid, with design temperature and throughput being achieved within days of hot commissioning. Gold recoveries have exceeded expectations, improving from around 70% prior to the installation of pressure oxidation to above 84%. The project has increased the nominal gold output at Macraes from 120,000 oz/y to 170,000 oz/y. On-going plant optimisation for process parameters is discussed, giving rise to flexibility in gold production, with key controlling parameters exceeding design.

Jan 1, 2000

Many mining operations generate seismic signals. They come from blasting and from underground mine failures such as rockbursts, longwall first caves, coal bumps and pillar collapses. Traditionally, seismic motions have been of concern on a local scale because they could create damage to structures at the mine site or at neighboring locations. Recently, there has been much interest in the Comprehensive Nu-clear-Test-Ban Treaty (CTBT). It prohibits any kind of nuclear explosion, anywhere. So distinguishing signals of mining operations from a possible nuclear explosion becomes important. An international monitoring system (IMS) is being implemented to verify the Treaty when it is ratified. It includes a large number of seismic stations capable of recording signals at regional (200 to 2,000 km or 124 to 1,240miles) and teleseismic (more than 2,000 km or 1,240 miles) distances.

Jan 1, 2000

By E. M. Frizzell

Development of mobile crusher systems for surface mining, allowing extension of continuous conveyor haulage systems into the pit, is traced from its introduction to the present. Variations in configurations are reviewed, and the compelling reasons for using mobile crusher systems are explored.

Jan 1, 1983

DESCRIPTION OF OREThe ore consists, in general, of a very finely grained mixture of sphalerite, galena, and pyrite, with a gangue of quartz and schistose material, and contains about one ounce of silver to the unit of lead.Minor minerals are chalcopyrite, tetrahedrite, and ruby silver. The amount of gangue within the ore-bodies themselves is usually less than 20% of the weight of the whole. The ore is banded in a way that corresponds to the structure of the original schists, and is by no means uniform in composition-at one point, for example, blende may predominate, and a few feet farther on the body may become highly pyritic.Owing to the intimate association of the mineral constituents of the ore, it is very difficult to separate them from one another.Although this remark applies to ore from all parts of the field, the difficulty is particularly noticeable with Rosebery ore, the minerals of which are more intimately mixed, and are of smaller grain size than are the minerals of the Hercules ore.To effect a reasonably clean separation, it is necessary to grind the ore so that 90% passes a 200-mesh I.M.M. screen. Microscopic examination of the crushed product shows that 85% of the minus 200-mesh material is less than 30 microns in diameter, or, in terms of screen sizing, is minus 400 mesh. Particles under 30 microns are found to consist, of one mineral only, but in particles over this size separation has not always been effected. For instance, it is known that part of the galena and of the pyrite in the zinc concentrate is associated with sphalerite, and that part of the galena in the mill residue is associated with pyrite. There is only slight association between the minerals in the lead concentrate.

Jan 1, 1927

By R. Hummel

When the slope angles of the southern side of the Venetia open pit were required to be flattened by some 20 degrees after an analysis completed by De Beers geotechnical engineering in conjunction with SRK, the additional waste stripping tonnage generated was in the order of some 70 million tons. The potential cost of having to move this tonnage had a significantly negative effect on the Net Present Value of Venetia Mine, challenging the viability of the third pushback and rendering a potential fourth pushback completely uneconomic. This paper details some of the innovation that went into the design and planning process undertaken to virtually negate the instantaneous effect of the flattened slope angles and the associated waste tonnage as well as further improve the NPV of Venetia Mine and bring the fourth pushback back into economic viability. This process has become known as NPV+ and is anon going exercise in waste reduction/deferment and revenue advancement.

Jan 1, 2001

By B. H. Clemmons, B. G. Saunders, R. H. Stacy

"INTRODUCTION This investigation was undertaken to determine the response of Birmingham (Alabama) red-iron ore to heavy-medium concentration. Specifically, the work involved a study of the efficiency of the process in separating coarse gangue diluents from the ore and an endeavor to evaluate the potential economic results. The investigative work was not intended, nor is it to be construed, to be adequately exhaustive in scope to enable immediate plant construction. Rather, the primary objective was to determine the grade of ore that could be produced by heavy-medium treatment and the resulting indicative or tentative benefits to be derived from such treatment. The latter, in turn, would determine the merits of the more exhaustive study that would be required for an ultimate decision on the heavy-medium treatment of the ores.The problem of avoiding excessive contamination of red-iron ores by shale and/or ferruginous sandstone has been before the operators of the iron mining industry of the Birmingham, Alabama, district for many years. Within the last two decades, increased mechanization of mining methods has increased this contamination to a considerable degree. In fact, general utilization of scraper loading and other mechanical methods of mining, in conjunction with small increases in the natural insoluble content of the ores, in some cases has actually resulted in the production of ""acid"" or excessively insoluble ore, where ""basic"" or excessively lime ores were produced formerly.The contaminating materials are derived largely from roof spells and natural parting seams in the ore, a condition that to some extent has been aggravated by the irregularity of the ore beds. The latter have been subjected to both primary and secondary folding in many places. Considerable faulting has taken place, also. In many localities these conditions render virtually impossible complete avoidance of ore contamination from the over and underlying sandstones and shales. However, in a few localities, where the ore beds are less disturbed and shale partings are absent, mining can and is being accomplished with relatively little dilution."

May 1, 1948

By C. A. Carroll

In February of 1989 the Mission Complex of ASARCO Incorporated completed an expansion of its concentrator, raising the base mining rate from 25,900 TPO (28,500 STPD) to 37,200 TPO (41,000 STPD). The expansion was accomplished by extending the twelve existing Mission ball mills in length, by installing the grinding circuit from Asarco's idled Sacaton Concentrator along with various auxiliary equipment, and by modifications to the flotation circuit and water systems. This paper will give a brief history of the consolidation of the ore body which made the expansion possible and explain the various parts of the expansion.

Jan 1, 1990

By Steve Kral

When the price of gold cracked the US$9.60/g(US$300/oz) mark last year, the gold-mining industry began to crank up again. This followed several years of gold prices that had languished in the mid-200s. Existing mines increased production and mines that had lain dormant for many years were getting second looks. The United States still produces a large amount of gold. But not much of the new production is coming from that country. Instead, strict environmental regulations still have companies wary of trying to invest the millions needed to start a new mine or expand existing ones. And after years of studies and negotiations between legislators, environmental interests and the mining industry, the United States still has not crafted a new mining law.

Jan 1, 2003

By Sahoo K. C

Traditionally, the blast furnace (BF) has maintained a dominant position as the primary source of iron units. Notwithstanding the efficient nature of the process in respect of its material and energy consumption, the conventional blast furnace route is faced with limitations such as stringent quality metallurgical coke, high capital investment, etc. While BF will continue to retain its predominant position as the foremost ironmaking technology, the alternate processes may also have a role to play. Direct Reduced Iron (DRI) or sponge iron industry is all set to take a firm root in India as one important solution to the problems of shortage of metallurgical coal and ferrous scrap and high investment costs faced by the country's steel industry. The commercial proven DR processes coupled with electric arc furnace (EAF) steelmaking have also offered a viable alternative to the blast furnace - basic oxygen furnace (BF - BOF) route for the installation of integrated plants under specific local conditions. The performance and efficiency of DRI processes mainly depend upon the chemical and physical behaviour of the raw materials especially the iron bearing materials. Iron oxide pellet and sized lump ore constitute the oxide feed stock, while pellets form an ideal feed stock for direct reduction, use of lump ore is economically advantageous because of its lower price. National Mineral Development Corporation Limited (NMDC), being one of the major producer of iron ore in the country since last four decades, has established technology and developed process flowsheets for production of suitable calibrated lump ore for DRI production, besides supplying the natural lump ore for conventional blast furnace requirements. In addition to the above, extensive pilot plant tests have been carried out at the R&D Centre of NMDC for preparation of iron ore concentrates suitable both for direct reduction and blast furnace grade pellet feed using the iron ore fines from its own mines and as well as from the other iron ore mines in the country. For utilisation of the huge quantity of slimes generated in its ore processing plants, NMDC has planned to set up the first commercial plant adopting the smelt reduction process (ROMELT Process) for production of pig iron from Bailadila slimes. The paper mainly deals with various beneficiation techniques adopted for production of DRBF grade pellet feed from iron ore fines. Also presented in the paper, the extensive work carried out at R&D Centre on preparation and evaluation of calibrated lump ore (Natural Pellets), based on which, suitable modifications are incorporated in the ore processing plants of NMDC for production and supply of the same to sponge iron industries.

Jan 1, 1999

By A. Kale

A chlorination pilot plant having capacity to produce 5?10 kg/hr of titanium tetrachloride is in operation at the chlorination facility in Mintek. The bubbling fluid bed chlorination plant can be operated in batch and/or continuous process to study the chlorination kinetics of various feedstocks. The chlorination of titaniferrous ores to produce titanium tetrachloride (TiCl4) was carried out during the commissioning of the pilot plant and also as part of the titanium programme carried out at Mintek. TiCl4 is a basic raw material for producing commercial titanium dioxide pigment and titanium metal. This paper discusses the challenges faced during the commissioning and operation of the chlorination pilot plant. It also discusses the effect on the auxiliary facilities and instrumentation as a result of the harsh operating conditions of +1000°C and use of corrosive gases like chlorine and titanium tetrachloride. It discusses the effect of physico-chemical properties of the titanium tetrachloride and iron chlorides. The effect on the chlorinator refractory lining due to heating and cooling of the chlorinator is also discussed. Besides the special provisions made during the design of the chlorinator, this paper also discusses the operational experience and possible solutions to be implemented in future. Keywords Fluid bed chlorination, titanium ore chlorination, titanium tetrachloride (TiCl4) production using fluid bed technology.

Jan 1, 2011

By Fermont F. Clarke, Others, Paul Zinner

"INTRODUCTION The Edison mine comprises workings on two irregular spodumene-bearing pegmatite dikes which outcrop near the town of Keystone in the southern portion of the Black Hills of South Dakota. The Bureau of Mines conducted an investigation of the Edison mine as part of a comprehensive study of the lithium mineral-production possibilities in the Black Hills area. The work was undertaken during the Second World War, when the demand for certain lithium salts and compounds exceeded the then small productive capacity of the industry.During the course of the project, the Bureau of Mines completed 13 diamond core-drill holes, aggregating 2,114.5 feet of drilling. Twenty-six cannel samples were taken from the main Edison shaft, and 13 miscellaneous samples were obtained to permit analysis of the efficiency of phases of mining and sorting operations. Metallurgical tests were made by the Bureau of Mines to investigate the feasibility of beneficiating spodumere-bearing ores from the Edison mine. 3/"

Apr 1, 1948

By Jennifer Riefenberg

Ground control hazards, coal quality, ore reserve estimation, and pollution modeling seem unrelated topics from most mining perspectives. However, geostatistical methods can be used to characterize each of these, and more topics. Exploratory drill core data, and continued drilling and field measurements, can provide a wealth of information related to each of the above areas and are often severely underutilized. Recent studies have led to the development of the Multiple Parameter Mapping (MPM) technology, which utilizes geostatistics and other numerical modeling methods, to generate a "hazard index" map, often from exploratory drill core data. This mapping has been presented for ground control hazards relating roof quality, floor quality, numerically modelled stresses due to mining geometry, and geologic features. A review of the MPM method, future directions with the MPM, and a discussion of using these and other geostatistical methods to quantify coal quality, ore reserve estimation, and pollutant modeling are presented in this paper.

Jan 1, 1996

By B. Arjang

ABSTRACT: Ground stresses are one of the significant factors in the context of rockbursts and underground instability at some hard rock mines in Canada. Overcoring strain relief measurements using triaxiaI strain eel is were performed at depths between 60 to 1890 m at several mine sites to provide stress data for stability analysis and optimum mine design. Pre-mining ground stress determinations from 64 stress tensor analyses resulted in the following average stress gradients: Maximum horizontal stress. -Hmax - 8.18 - 0.0122 MPa/m depth Minimum horizontal stress. _-,,min - 3.64 - 0.0276 MPa/m depth Average horizontal stress. -11, 5.91 - 0.03-19 MPs m depth Vertical stress. '-, - 0.0266 - 0.008 MPa/m depth The maximum and minimum horizontal compressive stresses. with an average ratio of 1.75 ,0..45. prevail in east--west and northerly directions. respectively. Horizontal compressive stresses in excess of vertical overburden load were determined. indicating large variations in ratios to a depth of about 1000 m with decreasing trend towards depth. From present data. a particular regional zoning for the magnitude and direction of horizontal stress fields cannot be outlined. A common feature at mines with near vertical orebodies is that the maximum horizontal compressive stress acts perpendicular to strike while the minimum horizontal compressive stress is aligned on-strike. The vertical stress components approach the gravitational overburden load.

Jan 1, 1989

By J. West

For many years line-of-sight (LOS) issues for underground mobile equipment is a growing focus of research. This research is a result of the numerous fatalities and injuries which occur in the mining industry and which are related to poor operator LOS. Three assessment methods are currently used to assess operator LOS of underground mobile equipment. The light filament (LF) method is a hands-on assessment method that is performed in the field. This method is not evaluated in this paper. The laser scan (LS) method of assessing equipment is a quick and reliable method that comes from the need to evaluate vehicles already located in the field. The computer simulation (CS) method can assess LOS issues using a computer aided drawing (CAD) model, which is useful for assessing current or prototype models. The purpose of the current research is to compare and validate different operator LOS assessment methods. Comparison of the results of the LS and CS visibility plots yielded similar quantifiable results. A visual comparison of the results further illustrate that the LS and CS methods are acceptable assessment tools for mobile equipment operator LOS evaluation. The visibility assessment methods are now being prepared as guidelines for the mining industry to assess current and potential designs.

Jan 1, 2007