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By Fumitaka Tsukihashi

Phase diagrams of the CaO-SiO2-FeOx-MgO, Al2O3 systems are necessary for the analysis of copper smelting reactions and sintering process of iron ore. The effect of MgO and Al2O3 addition on the liquidus of the phase diagram of the CaO-SiO2-FeOx system at low oxygen partial pressure was observed. The liquid phase area changed by the addition of MgO and Al2O3 with a changing oxygen partial pressure from 10-8 to 10-3 atm (10-1 to 102 Pa) at 1573K. The effect of Fe3+/Fe2+ ratio on the melting mechanism is discussed.

Jan 1, 2003

By B. K. Parekh, R. H. Mehta

Handling of fine coal is an importance issue for coal as well as the utility industry. Reconstitution in form of pellet or briquet would be desirable if it could be done economically. This paper evaluates the effectiveness of three binders e.g., asphalt- emulsion, corn starch and Brewex, in forming pellets of ultra-fine clean coal. It was found that asphalt emulsion and corn starch were not effective binders for ultra-fine clean coal, however, Brewex provided excellent quality of pellets, which exceeded all the minimum quasi requirements of coal pellets. INTRODUCTION Advanced coal preparation techniques (physical or chemical) are designed to process ultra-fine (minus 200 mesh or 74 pm) coal. The average particle size of the clean coal product is about 25 pm. Currently available dewatering techniques are effective in providing a 25 to 30 percent moisture product of this size coal slurry (Parekh et al. 1989). Handling and utilization of this dewatered ultra-fine size coal is difficult. Reconstitution, which includes pelletization, briquetting, extrusion, etc., of the dewatered coal product provides an ideal answer to handling and transportation problems. However, reconstitution of fines in the coal industry has not been successful due to various reasons. The most important criterion for its unsuccessful application in the coal industry is the cost of the binder (Capes et al. 1965). Various methods of reconstitution, such as briquetting, disk pelletization, extrusion pelletization and roller and die-pelletization, have been tested for fine coal agglomeration (Conkle et al., 1991) (Richards, 1990). Conkle et al., (1992) have provided a detail analysis of each technique in terms of moisture and operating cost requirements. According to Conkle, briquetting requires a product containing very low moisture, whereas pelletization can be done with coal containing up to 30 percent moisture. Currently available dewatering technique provides about 25 percent moisture product, thus, pelletization appears to be an ideal route for reconstitution. In this paper, results are presented on the comparison of three different binders i.e., asphalt-emulsion, corn starch and Brewers condensed solids (BCS or Brewex), for fine coal pelletization.

Jan 1, 1995

The structural pattern of Victoria shows the presence of EW, NW, NE as well as the more readily recognised NNW factors commonly associated with the goldfields. ENE and WNW trends are also present. This structural lattice affects all rocks of the State. Landsat imagery shows that the EW, NW and NE structural elements are closely related spatially to the distribution of Palaeozoic igneous intrusives, Cainozoic volcanic vents as well as all historically important gold mines. It is suggested that the EW, NW and NE structural grid visible on landsat imagery is a reflection of the structure of a mid-crustal layer situated between 3.5 and 17 kms below the surface. The points of intersection of the structural elements of the mid-crustal layer offer most favourable loci for the escape of energy in the form of heat. The correlation between the distribution of igneous plutons, volcanic vents and centres of mineralisation, all reliant on high levels of energy for their formation, indicates the stability of the structures of the mid-crustal layer since early Palaeozoic times. The deep level crustal structures are believed to be, related to the release of stresses placed on the crust since early Palaeozoic times by the rotation of the Earth. A geological model that accommodates the presence of a mid-crustal layer as well as the complexities of the recognised orogenic cycles of southeast Australia is suggested. All 1 000 kg Au reef and deep lead mines fall within 1.5 and 2.5 km respectively of strong linears associated intimately with plutons and volcanic vents. Future exploration of the State is more likely to meet with success if it too is confined to the evaluation of these and similar linears. The mode of mineralisation of any one centre will depend upon the temperature, pressure and geochemical gradients operating on the migrating mineralising fluids as well as the structures in the host rocks. These factors are likely to have varied considerably from one centre of mineralisation to the next and consistency of mineral isation form and depth should not be expected along the length of any single Linear.

Jan 1, 1986

By Lars Rossemyr, Terkel Rosenqvist

The equilibrium Mn + 2 IiCl = MnCl2(g) + H2 has been studied at 1090°C for pure manganese and for Mn-Si alloys. For this reoction a standard free energy of Fo1363, = - 19,700 i 300 col ioas found. Combined with other thermal data, the standard free energy of the reaction Mn(s, ß) + Cl2 = MnCl2(g) was derived: Fo=- 56,140 + 9.78 T log T - 40.10 T For the formation of the various manganese silicides the following free energies were obtained. 5 Mn + 3 Si - M1z5Si3 ?F°1363 = -41,500 i 1500 cal Mn + Si - h.lnSi ?F°1363= -10,000 i 500 cnl Mn + 2 Si = MnSiz ?F°1363= -11,500 ± 500 cal In the search for a method suitable for the study of thermodynamic properties of certain alloy systems, it was found that the heterogeneous equilibrium between the alloy and a gas mixture consisting of hydrogen chloride, hydrogen, and volatile metal chlorides has considerable advantages. In addition to giving thermodynamic information about the alloys, such measurements may be used to derive thermodynamic data for the volatile metal chloride itself. The present paper gives some results which were obtained for manganese silicides and manganous chloride. Similar studies are presently being carried out for the iron silicides. The phase diagram of the Mn-Si system is rather well known,' but no information exists to the authors' knowledge about the thermodynamic properties of manganese silicides or about the chemical activities in molten Mn-Si alloys. At elevated temperature, manganese may react with hydrogen chloride according to the equation: Mn(s, ß ) + 2 HC1 = MnC1, (g ) + H2 [ 1] with the equilibrium constant The value of K, may be determined from measurements of the gas composition in equilibrium with pure manganese. When this value is used in connection with measurements on manganese alloys, the chemical activity of manganese in the alloy may be derived. Initial calculations showed that around 1000" to 1200°C the equilibrium constant K1 has a value of a few thousand, i.e., the reaction is shifted far to the right. In order to study this rather unbalanced gas composition, a flow method was used in two slightly different modifications. For all experiments with manganese silicides and for some experiments with pure manganese the apparatus shown on Fig. 1 was used. A bed of the metal or alloy was placed in a tube furnace. The refractory tube had an internal diameter of 14 mm and the bed was 75 mm long. Electrolytic manganese of high purity and silicon, 99.95 pct Si, were used as raw materials. All alloys were prepared by melting weighed amounts of the elements in a high frequency induction furnace in argon atmosphere. The melting was done in a silica crucible which was placed inside a graphite shell. The alloys were crushed to - 10 +40 mesh and analyzed chemically. Also, for the pure elements, the same size fraction was used. A controlled gas mixture of purified hydrogen and from 3 to 12 pct HC1 was passed through the bed where it reacted with manganese according to Eq. [I]. The volatile manganese chloride was collected in a condenser placed in the cooler part of the furnace tube. The gas mixture before and after the furnace was sampled and analyzed by absorption of

Jan 1, 1962

By E. W. Johnson

"The title of my paper is ""I 'Wonder Where The Yellow Went"". As you can readily guess, it is not related to an old-fashioned ""Pepsodent"" sales pitch! Rather, it concerns a situation which arises all too frequently in some gold milling operations, namely when actual ounces of gold production do not come up to estimated or projected ounces. The boss man scratches his head and wonders where the missing gold has gone and how it has disappeared. The problem, if one exists, is amplified if one forgets that an estimate is just that - an estimate - and not a hard fact - even though the numbers are produced by computers. And yet, from the point of view of engineering; financial and production planning and security; it is most desirable to tie together all data relating to production estimates, losses and actual production.In the course of this paper reference will be made to the term ""variance psychology"", to a few of the physical properties of gold and to the nature of its occurrence in Canadian ores, in relation to the topic under consideration. Activities which have a bearing on production estimates will be reviewed. These include: weighing, sampling, assaying, estimating residual losses and, in cyanide plants, gold precipitate production. Mention will be made of apparent, unaccounted for and unknown losses. In conclusion, I shall draw from personal experience and relate three examples of ""Where the Yellow Went''."

Jan 1, 1986

Human engineering was the keynote of the thirty-ninth annual meeting of the American Society of Mechanical Engineers, which was held in New York, December 3-6. This note was sounded by President Charles T. Main in his address at the opening session and was carried through by all the speakers. In his survey of the year's work, he said that more than 6000 names of engineers were furnished the Government for filling a wide variety of positions. In addition to the 1400 members in service, two members of the council of the society are in uniform in France and one, as a distinct war service, is in charge of one of the largest shipyards. After giving other ways in which the Society has helped the Government, President Main called attention to the necessity for thoroughgoing efforts to increase production and the settlement of questions involving industrial relationships. At the following meeting, President Adams of the American Institute of Electrical Engineers called attention to the necessity of meeting labor in a progressive way, facing labor questions fairly and squarely, as the real interests of labor cannot be separated from those of the engineer. Charles E. Knoeppel, discussing "Industrial Organization as It Affects Executives and Workers," said the problem of the cost of living might be settled in two ways: 1, there must be more producers, and 2, there must be a greater amount supplied by those now producing. The first solution is practicable, he said, if labor is allowed shorter hours, better conditions, and a remuneration that will attract workers. The second can be employed by eliminating waste, standardizing conditions, setting fair tasks, and allowing men to earn an amount that will compensate them for' their skill and cooperation. Dudley R. Kennedy of Philadelphia, employment manager of the American International Shipbuilding Corporation, said the human-engineering phase of the country's industrial development had generally been overlooked. "We hardly yet know what competition means; we will learn it within a few years. Permit me to prophesy that the executive of the next decade will be the man who best knows men. He will be an originator, a handler of men as individuals, a handler of men in the mass, a leader not a driver, a very human man. The science of human engineering is here to stay. The study of human characteristics is the most enduring, as well as the most fascinating in the world, and still the most complex."

Jan 1, 1919

By M. G. Skowroski, G. G. Eichholz, J. P. Ambrose

Introduction It has long been known that there are extensive deposits of phosphate-bearing deposits in the Coastal Plain of Georgia in many locations that are similar to those being mined commercially in central Florida. A major drilling program was conducted in 1966-67 by the Georgia Geological Survey (GGS). The economic potential of some of the material uncovered was evaluated at that time by a team at Georgia Institute of Technology led by Dr. J.E. Husted. There were some promising results. Since then, there has been little commercial interest in pursuing this matter, though the potential for development remains. In the long term, Georgia's phosphorite deposits could be a major source of income to the state if they were commercially processed. Phosphorite deposits contain significant levels of uranium and thorium. Uranium concentrations in Florida phosphate aggregates have been found to be 120 to 140 ppm. The presence of high concentrations of uranium means that there is a small but finite concentration of radium, which subsequently leads to radon gas emanation. It is the radon emanation and its progeny that may pose the largest health problem in many types of mining. Surface mining operations can possibly elevate the radon and radon daughter concentration in the vicinity. There is always some public concern whether any increase in the radon concentration in the atmosphere by mining (surface mining in the phosphorite case) could elevate the risk of cancer in the nearby population. At the present time, a great deal of attention has been devoted to the possible health effects of radon and its decay products in the inhaled air in mines and inside buildings built on mill tailings or uranium-bearing rock (Gesell and Lowder, 1980). Several evaluations have been published on the potential health effects of the Florida phosphate operations (Guimond and Windham, 1975; Roessler et al., 1980; Travis et al., 1979) and for buildings incorporating phosphate slag aggregates (Kahn, Eichholz, and Clarke, 1983; Roessler, Roessler, and Bolch, 1983). They all indicate that such potential effects are small, but tangible, compared with other radiation effects, for instance in the nuclear industry (Cohen, 1981). In view of the current concern, especially by the US Environmental Protection Agency (EPA), with the radiological consequences of large-scale mining of uranium-bearing phosphate rock (Guimond and Windham, 1975), it was decided to assess the potential radiological consequences if the Georgia deposits were developed. This paper presents an attempt to estimate the magnitude of any radon-based health effects that might arise from future mining operations in selected areas of the Georgia coastal region. To do this, a calculational model was developed that took into account the mining operations themselves, the atmospheric dispersion of the radon released, and the radon daughter concentrations in nearby towns. The model was applied to both extremes. The first application was a hypothetical mining operation in Echols County. Echols County is very sparsely populated and, unless living very close to the site, a person would probably experience little radiation exposure, if any. The model tries to prove this point. The second application was at a site near Savannah, Georgia. Both sites contain economically feasible phosphorite deposits and were not entirely hypothetical in that sense. Site selection In the course of the South Georgia Minerals Program (Furcron, 1967), an extensive series of drill core samples had been collected from various mineral occurrences in the coastal plain. It was found that the cores from the previous drilling program (Furcron, 1967), though carefully preserved, were not readily accessible. But the GGS reports did contain gamma logs of all the holes surveyed. With the cooperation of Dr. Neal Shapiro of the Survey, some core samples were selected and assayed, and used to calibrate the gamma log data. Samples from locations known to have detectable radioactivity were screened and counted. Their measured uranium content was used to calibrate the gamma log profiles for those same holes as obtained by the GGS. On this basis, two of the higher-level sites were selected and the calibration was used to obtain integrated uranium concentrations over the length of the borehole. It is customary to describe radon and radon-daughter concentrations in "working levels" (WL), where one WL represents a concentration of radon daughters capable of releasing 130 000 MeV of alpha particles, equivalent to 100 pCi of radon in equilibrium with its daughters per liter of air. A representative concentration is 0.15 WL, below which radon levels are widely considered to be negligible. For the mine sites selected, the surface area and rock volume were determined to estimate their radon content. Working-level values were then estimated for the assumed radon release from the crushed ore and the exposed surfaces of the mine pit. According to Kisielewski (1980), 93.4% of all radon released from open-pit operations is released from the ore zone; thus, the calculations assumed that those surface areas were the main sources.

Jan 1, 1987

A mine that staggers the imagination is Chuquicamata, the granddaddy of them all. In 1968 production exceeded 300,000 tons of copper. Production began in 1915 and mining proceeded solely on oxide ores until 1953 when the first treatment of sulfides began. Today the company has mined about 1.2 billion tons of all types of material since inception. The accelerating rate of output can be gauged by the comparable 1946 figure of production-to-date which was 350 million tons. No single mine comes close to touching Chuqui for productivity at its high annual metal yield mining only 90,000 tpd of ore at the luxurious waste-to-ore ratio of 0.6 to 1. However, the complexity of the operation is enormous and the experience required to synchronize the various processes is masked by normal operations and only becomes apparent in times of emergency such as when the slide took place in the pit in February.

Jan 11, 1969

By Luiz R. P. De Andrade Lima

This paper presents a mathematical model for the oxide copper ore heap leaching process. The data used in the model include physical-chemical, .geometrical and operational data, as: leachable metals ore contents, .flow rate and acid concentration, parameters of passivity, ore size distribution, the average residence time of the solution in the heap, height, irrigated area and weight of ore in the heap. In this model the heap is divided into horizontal and plane layers of constant area. The flow of the liquid in the heap is considered unidirectional and the solid-fluid reaction model is considered under diffusive control. The average residence time of the solution into the heap and the apparent effective diffusivity of the acid through the ore particles have .a significant influence on the rate of the copper extraction and its concentration in the pregnant solution; therefore these parameters are used in the model calibration. When this algorithm was applied to a laboratory test, the results showed that the model is adequate to predict the process performance.

Jan 1, 1999

Meeting of Oct. 23, 1914.-It was voted to take no action concerning the proposed amendments to Article VIII, Sections 2 and 3, but that they be sent to the membership, as provided by the Constitution, together with a statement of the arguments for and against the proposed changes. It was voted that the following proposed amendment, which had been unanimously approved at the annual meeting of the Institute on Feb. 18, 1914, be sent to the membership as provided by the Constitution, together with the approval of the Board of Directors of this change: Article III, Section 1, paragraph 3, sentences 2 and 3: substitute the following: "Any Member, Junior Member or Associate in arrears for two years shall be dropped from the rolls unless the time for payment is extended by the Directors. A Member so dropped may be reinstated by the Directors on paying the arrears of clues and other indebtedness with which he was charged on the books of the Institute it the time he was dropped. A Member or Associate thus reinstated shall receive the Transactions for the back year for which he pays." It was unanimously voted to extend the sincere thanks of the institute to Samuel A. Taylor, Chairman, and to each member of the several Committees of the Pittsburgh meeting, for the enjoyable and successful meeting which they brought about.

Jan 12, 1914

By Germán Ramón Rojas

El presente texto describe una alternativa de sistema de gestión en seguridad minera con el objetivo de prevenir y controlar riesgos dentro de una estructura organizacional y señalar su importancia en la cultura de una empresa. Para ello, el autor otorga un concepto integral de cómo gestionar el sistema de seguridad dentro de una empresa a través de la identificación y control de los factores críticos de éxito, los patrones de conducta Y de sus empleados; así como del fomento de cultura organizacional de las empresas mineras para una gestión preventiva.

Sep 14, 2009

By Y H. Zhu, X X. Tang, Y C. Yin, M L. Xing

Based on the stiffness theory, the stiffness difference and energy supply of surrounding rocks are important inducing factors for strain burst. However, due to the lack of multi-level low stiffness testing machine, there are few experimental studies on rock failure mechanisms under the influence of loading stiffness. This paper introduced a self-developed rock testing system with changeable stiffness. The main testing machine of this system is a combined structure of inner and outer frame. The change in the loading stiffness is achieved by using a stiffness servo control system to control the energy accumulation in the inner frame. The tests of the sandstone specimens under three different loading stiffnesses in the testing system showed that the loading stiffness did not significantly affect either the uniaxial compressive strength or the Young’s modulus of the rock. However, the post-peak stress-strain curve of the rock became smoother and steeper when the loading stiffness was decreased, and the stress drop rate increased. It is shown that the stress drop rate had a power function correlation with the loading stiffness. After the peak load, the inner frame of the testing system rebounded several times at high speeds. The magnitude of the instantaneous rebound speed and the rebound duration increased with the decrease of loading stiffness. Both the mean rebound velocity and the total rebound deformation had power function correlations with the loading stiffness. The loading stiffness has limited effect on the energy storage and energy dissipation characteristics of the specimen, while the released energy of the testing machine increases as the loading stiffness decreases, which is the key factor affecting the failure mode of the specimen. According to the test results, a rock burst mechanical model considering the stiffness is established, and the energy supply mechanism of rock burst is quantitatively explained.

Nov 29, 2022

By J. F. Rakszawski, Robert P. D'Orazio

The use of cyanide in the processing of gold has been documented for over a century. It is still one of the more effective methods of isolating gold, as witnessed by the fact that in 1987 cyanidation was used in the processing of 91.5% of the gold produced in the United States.

Jan 1, 1990

By Yapeng Zhang, Zhiwen Shi, Chaoquan Yao, Fei Wang, Xinyu Li, Jianliang Zhang

A great deal of iron ores which have special elements have been applied in the sintering process with the decreasing of high-grade quality iron ores resources. In this paper, the laterite nickel ores were added into three different kinds of iron ores respectively to make liquid phase formation research by software of Factsage and high temperature characteristic sintering experiments. The results showed that the adding proportion of laterite nickel ores should be less than 15% when the high temperature properties of the mixing ores were well. Increasing the mixing ration of laterite nickel ores in the sintering blending would play an important role in the reduction of the sintering cost.

Jan 1, 2015

By Albert L. Brautigam, Michael C. Leigh, August J. Kwitowski

The U.S. Bureau of Mines developed and tested a teleoperating system to control a new highwall mining system. A remote operator was provided out-of-sight sensory information and control of coal extraction and haulage equipment. Surface and production testing proved that the teleoperating system supplied the operator with sufficient sensory information to operate the mining system. Details on the teleoperating system provided in this report include (1) sensor selection, (2) a description of the electronic control system, (3) equipment selection and modifications, (4) the positive test results, and (5) recommendations for system improvements.

Jan 1, 1992

By Walter Miller

AFter a year's continued impact of war, the task of the petroleum-refining industry stands out clearly and looms up in larger aspect. This time it is not, as it was so largely in the first World War, simply a matter of increased quantity—more and more of the same petroleum products that had substantially been standard for years. In this era the emphasis is largely on newer and improved materials which had been produced, if at all, in comparatively insignificant quantities, and for which manufacturing equipment was not available on a large scale. At the beginning of 1942 four great product needs (besides a number of lesser ones) confronted the industry: 100-octane aviation gasoline, toluene for T.N.T. production, high-quality lubricating oils for aviation and Army equipment service, and petroleum chemicals for synthetic rubber manufacture. The difficulty in presenting a review of engineering progress in petroleum refining during 1942 is that there is so little one is free to say about so much which has been and is being accomplished. At the opening of 1942 the program was to increase the then existing capacity of 50,000 bbl. a day of aviation gasoline to over 150,000 bbl. daily by building new plants at an estimated installation cost of $150,000,000. Later in the year. after the announcement by President Roosevelt of a large increase in the program for war-plane building, additional contracts were made between the Reconstruction Finance Corporation and rehers to raise the capacity to 250,000 bbl. per day. The greatly increased scope of the war activities in all parts of the world, the obligation of the United States as the arsenal of the United Nations, and the greater importance and use of bomber, transport, and cargo planes will undoubtedly bring about plans and installations for a further increase in production of aviation gasoline over the present announced plan. In this connection, Jesse Jones, Reconstruction Finance Corporation Chairman, announced that as of Oct. 31 the R.F.C. had through its subsidiary Defense Plant Corporation entered into contracts for the construction, expansion, or equipping of 28 plants to increase 100-octane aviation gasoline production, but gave no data on 'capacity involved or completion dates. His list did not, of course, include a number of existing plants, and some installations being made by companies who are themselves financing the construction. Production from existing operating installations was materially increased in a number of instances as a result of pooling knowledge of improvements in operation and also by the exchange of Components going into 100-octane blend to enable greater quantities of aviation gasoline to be produced from the over-

Jan 1, 1943

By Walter Miller

AFter a year's continued impact of war, the task of the petroleum-refining industry stands out clearly and looms up in larger aspect. This time it is not, as it was so largely in the first World War, simply a matter of increased quantity—more and more of the same petroleum products that had substantially been standard for years. In this era the emphasis is largely on newer and improved materials which had been produced, if at all, in comparatively insignificant quantities, and for which manufacturing equipment was not available on a large scale. At the beginning of 1942 four great product needs (besides a number of lesser ones) confronted the industry: 100-octane aviation gasoline, toluene for T.N.T. production, high-quality lubricating oils for aviation and Army equipment service, and petroleum chemicals for synthetic rubber manufacture. The difficulty in presenting a review of engineering progress in petroleum refining during 1942 is that there is so little one is free to say about so much which has been and is being accomplished. At the opening of 1942 the program was to increase the then existing capacity of 50,000 bbl. a day of aviation gasoline to over 150,000 bbl. daily by building new plants at an estimated installation cost of $150,000,000. Later in the year. after the announcement by President Roosevelt of a large increase in the program for war-plane building, additional contracts were made between the Reconstruction Finance Corporation and rehers to raise the capacity to 250,000 bbl. per day. The greatly increased scope of the war activities in all parts of the world, the obligation of the United States as the arsenal of the United Nations, and the greater importance and use of bomber, transport, and cargo planes will undoubtedly bring about plans and installations for a further increase in production of aviation gasoline over the present announced plan. In this connection, Jesse Jones, Reconstruction Finance Corporation Chairman, announced that as of Oct. 31 the R.F.C. had through its subsidiary Defense Plant Corporation entered into contracts for the construction, expansion, or equipping of 28 plants to increase 100-octane aviation gasoline production, but gave no data on 'capacity involved or completion dates. His list did not, of course, include a number of existing plants, and some installations being made by companies who are themselves financing the construction. Production from existing operating installations was materially increased in a number of instances as a result of pooling knowledge of improvements in operation and also by the exchange of Components going into 100-octane blend to enable greater quantities of aviation gasoline to be produced from the over-

Jan 1, 1943

By K. Meyer, M. E. Goddfellow

"At Teck-Corona Operating Corporation's David Bell Mine, a water quality management strategy is employed to produce both a chemically and biologically clean effluent prior to discharge to the environment.The strategy includes operating methods to minimize contaminants leaving the concentrator and an effluent treatment plant for cyanide, antimony, and heavy metal removal of concentrator, mine and site waste streams.Concentrator practices, the effluent treatment plant, process chemistry and the present day performance of the water quality management strategy are reviewed.INTRODUCTIONThe David Bell Mine is located in the Hernia gold camp 35 km east of Marathon, Ontario. The concentrator has a design throughput of 1,000 tonnes per day. ROM ore (-6"") is ground in a semi-autogenous mill followed by a ball mill, thickener, leaching, and carbon-in-pulp gold recovery unit operations. The concentrator flow sheet is shown in Figure 1."

Jan 1, 1991

"Placer Dome Inc.'s Dome Mine is located in South Porcupine, Ontario and has been in production since 1910. In the past, the mill leach circuit was preceded by preaeration and primary filtration circuits. These circuits were operated to overcome the effects of pyrrhotite in the ore which reacts with cyanide to form cyanates and thiocyanates and also consumes oxygen.In early 1989, primary filters were by-passed for an extended period. Actual plant results showed no affect on gold recovery or cyanide consumption so the circuit was left off-line permanently with significant cost savings.In 1990 it was determined that considerable savings could be realized underground if backfill storage facilities were located in the mill. It was decided to convert the preaeration pachucas to backfill storage tanks on a trial basis. The trial proved successful with no effect on recovery or significant increase in reagent consumption occurring due to the elimination of the preaeration circuit. The converted pachucas worked well as backfill storage tanks.Modifications such as these have helped to keep the Dome's millings costs among the lowest of Canadian gold producers."

Jan 1, 1992

By B. Mishra, A. Staley, D. Kirkpatrick

The major waste product of the alkaline extraction of alumina from bauxite (Bayer Process) is known as red mud. Approximately one ton of red mud is produced for every two tons of bauxite mined. The red mud produced from Jamaican bauxite is rich in hematite, alumina and titanium oxide. It has been shown that more than 90% (by weight) alumina can be recovered from red mud by soda ash sintering and caustic leaching. Hematite can be carbothermically reduced with a degree of metallization of more than 94%, resulting in attempts, for magnetic separation. These separations are desirable because there are no waste products generated. Consequently, there is an opportunity for complete utilization of the waste material. Conversely, the preseparated material could be charged through the tuyeres in an iron blast furnace, or it could be smelted to produce pig iron. If smelted, the concentration of titanium oxide in the slag would be high enough to justify its recovery by an established acid-leach process. This paper describes the results of alumina recovery and the plans for titanium oxide recovery from red-mud. In addition, the situation of ongoing efforts in iron extraction, particularly, the method of magnetic separation of the reduced material. The problems associated with the use of reduced red mud as an alternative to direct-reduced iron (DRI) is also discussed. A critical assessment of the recovery sequence chosen for the products is described based on economics. Key words: Red mud, Waste product utilization, Alumina recovery, Titanium oxide, Iron

Jan 1, 2003