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By John Blackshaw

NEW sources of supply of tungsten concentrates became necessary when the flow from the Far East was blocked in 1942. In Canada, one source has been noted in the workings of the Hollinger mine at Timmins, Ontario. For many years, a small amount of scheelite had been removed with the gold ore, and an appreciable tonnage of scheelite still remained in the mine. At the request of the Dominion Government, a plant was built to recover this scheelite in the form of a concentrate that could be used by the alloy-steel industry without further preparation. The plant began operating early in March, 1942, and a small tonnage of ore, carrying scheelite and gold values, has been treated daily since then. The possibility of recovering the scheelite had been considered on several previous occasions. Each time the proposal had been given up because the total profits from the enterprise were estimated to be insufficient to repay the capital cost of building the recovery plant. At the time the plant was built, additional information had been gathered about the tonnage and grade of the scheelite ore in the mine, and several thousand tons of ore grading higher than 0. 25 per cent WO3 (tungstic trioxide) were known to be available.

Jan 1, 1943

By C. J. Wilhelm

Brine produced from subsurface formations may be employed successfully instead of fresh water as a flooding, medium in the secondary recovery of oil. The feasibility of this substitution has been proved in the shallow "shoestring" area of eastern Kansas and northeastern Oklahoma, where the supply of fresh water often is limited. In this procedure all brine produced with the oil is returned to the formation and thus is prevented from contaminating streams and fresh-water supplies. This report includes a detailed description of a "flood project" in eastern Kansas studied by the Bureau of Mines. In an attempt to determine whether brine, when handled properly, can be used as effectively as fresh water in flooding oil from partly depleted formations, an analysis was made of all known conditions that influence flooding.

Jan 1, 1941

By T Niitti, J Turunen, P B, A Rinne

In todayÆs marketplace, with high metals prices, many operations are faced with the challenge of improving recovery in the particle size ranges which are normally difficult to recover. This presentation focuses on the various methods used to alter the flow dynamics in a mechanical flotation cell, thereby improving metallurgical results. Modern computational fluid dynamics (CFD) tools have been used in the design phase, with subsequent validation at the plant. Some of the validated variables include mixing profile, power draw and local air hold-up. This presentation underlines how modern CFD analysis can be used to screen and select different approaches before commencing costly trial-and-error experiments at plant scale. Two methods of affecting flow dynamics are discussed û firstly, by altering the geometry of the rotor-stator area and, secondly, by fitting additional features in the tank. The rotor-stator area can be modified to provide more concentrated turbulent kinetic energy or, respectively, to provide more pumping efficiency with less attrition. The tank can be fitted with various additional features, aimed to create different particle suspension profiles. The benefit of both methods is that they can be applied not only to newly installed flotation technology, but also to existing plant cells, thus enabling potential improvement in the mixing profiles, solids suspension, tank sanding and metallurgical performance. Results of several sitesÆ tests are discussed in terms of flow variables measurement as well as metallurgy. This paper demonstrates the effects of different flow dynamics on the mixing profiles and metallurgical results of existing mechanical flotation cells.

Jan 1, 2006

By Marco Sonnenschein

As time is costly, engineering companies have developed methods, procedures and mechanical equipment to tunnel faster. But the best excavation method will not be able to cope with the time pressure if there is not a reliable backup system. Therefore, the application of belt conveyors for tunnel boring machine (TBM) drives as well as for drill-and-blast driven tunnels assure a quick and smooth removal of excavated soil in order to enhance the efficiency of the tunneling equipment. During the last 10 years, belt conveyor systems have achieved ?state-of-the-art? levels and have become the first choice for muck removal systems in both TBM and drill-and-blast driven tunnels. Because time has become such a key criterion in tunneling projects, it is essential that all equipment is operated so as to derive optimum efficiency and minimize costs. Efficiency also means to think about new tasks for existing technologies.

Jan 1, 2012

By Duanyou Li, Qing Xiao, Zhiwang Wang, Xiaoqing Gan

"Seepage is a major cause of earth-rockfill dam failure. Numerical simulation of infiltration process, distribution of drift, flow velocity and direction after the impoundment can guide seepage control and evaluate its effects. A double field coupling model is established based on soil consolidation theory and the interaction between the seepage field and the temperature field. The simulation is implemented under the situation of core wall setted, core wall not setted, and core wall setted with concentrated leakage. The results indicated that the saturation line height was significantly reduced due to impervious core wall, and the temperature distribution is uniform above the saturation line. If concentrated leakage occurs, temperature distribution of dam was significantly changed, which is consistent with theoretical inference.INTRODUCTIONEngineering seepage field distribution must be calculated in seepage control design, optimization, and correction of new engineering construction of earth dams, as well as in seepage monitoring and evaluation of existing earth-rockfill dams. The aim of calculation is to identify the important parameters in seepage field, such as the coefficient of permeability, seepage flow, pressure, head, and allowable seepage slope, for effectively implementing seepage control design, correction, safety assessment, and anti-seepage reinforcement. These seepage parameters usually can be obtained by in-situ test and back-analysis based on reliable monitoring data.In order to obtain reliable monitoring data and reflect the earth-rockfill dam seepage state and change process, appropriate monitoring technology and monitoring method is necessary. The traditional seepage monitoring method is through site inspection and sensors (e.g., osmometer, piezometric tube and measuring weir) that buried in the structure and its foundation. However, there are still some disadvantages:"

Jan 1, 2015

By Roman Y. Poderny, Vladimir V. Rjevskii

In the USSR, the Moscow Institute of Radio Electronics tronics and Mining Electro-Mechanics (MIRGEM) has started what it hopes will become a nationwide movement to educate mining students in the precise specialties that industry has come to require. Courses for mining engineers, the MIRGEM faculty proposes, should dovetail as exactly as possible with specific jobs available in the mining profession. Acting upon this thesis, MIRGEM revised its own curriculum in 1962 and has since presented an over-all plan for Soviet mining education before two mining school conferences as well as the Ministry of Higher Education and a number of major Soviet industrial ministries. The plan was universally approved with some suggested revisions. SOVIET MINING EDUCATION TODAY At present, mining education in the Soviet Union covers the exploitation of solid minerals and raw materials, including coal as well as ferrous and nonferrous metals. The extraction, storage, and refining of oil and gas is treated as a separate discipline. In all, there are 33 Soviet universities and institutes that train mining engineers for careers in the industrial, research and educational fields.

Jan 9, 1966

By D Roughsedge, J van der Sandt, L van den Berg

Axial flow fans are commonly used as auxiliary fans in underground mines to supply air to development headings. As diesel dilution requirements increase the fans used in conjunction with ventilation bags are becoming larger in diameter to move greater quantities of air over greater development distances. It is not uncommon for mining operations to sometimes use a number of these larger auxiliary fans with high airflow capacity in parallel as primary fans for the operations. These primary fan stations are often considered temporary installations and the fan selection and fan station design is rarely optimised. These temporary installations may become permanent resulting in an inefficient or unreliable primary ventilation system. A recent study looked at the likely causes of multiple primary fan failures at one operation with axial fans installed as primary units where the fan selection and fan station aerodynamic design was far from optimal. This paper explores some of the typical mechanisms of failure such as high pressure stall, unbalanced airflow, and fan tip speed as well as fabrication material. The paper proposes a number of good practise principles that should be considered during the design of a fan station. A second topic covered is the advantages and disadvantages of using different types of fans such as axial, mixed flow and centrifugal units. Here the concept of fan specific speed and its relevance to fan selection is discussed. Finally the paper quantifies the effect of using a high pressure auxiliary fan as a primary fan in a low pressure circuit, which may increase the mineÆs operation cost.CITATION:van der Sandt, J, van den Berg, L and Roughsedge, D, 2013. Practical considerations when using auxiliary axial flow fans as a primary mine fan, in Proceedings The Australian Mine Ventilation Conference , pp 63-70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By James A. Robertson

"In the Blind River area Proterozoic clastic and sedimentary rocks and minor volcanic rocks (The Huronian Supergroup) uncomformably overlie and trangress northwards over dominantly granitic Archean terrane (2500 + Ma) and are intruded by Nipissing Diabase (2ll5 Ma). Later deformation and metamorphic events are recognized. The developing depositional basin was controlled by the incipient Great Lakes Tectonic Zone marginal to the Algoman Craton.The Matinenda Formation (basal Huronian) comprises northwards-derived fluvial arkose, quartzite, and pyritic, uraniferous oligomictic conglomerate which contained in 1981 some two-thirds of Canada's uranium resources. Production to December 1981 from Elliot Lake totalled 98.3 thousand tonnes U for an average recovered grade of 0.1% U with an additional 671 tonnes U recovered by leaching at Agnew Lake. The remaining resources are at lower grades. Some thorium and yttrium have been produced. Minor amounts of gold reflect the paucity in the source area. Gold is better-developed in the Huronian north of Sudbury reflecting the local source area.The conglomerate beds lie in southeasterly-striking zones controlled by basement topography down sedimentation from uraniferous Archean granite. Uraninite textures, the distribution of monazite, and local enrichment by reworking indicate a syngenetic, probably placer, origin of the mineralization. ""Brannerite"" has formed by solution of uranium from the margins of the uraninite grains and redeposition on the original titaniferous minerals. Penecontemporaneous volcanics may have been a source for sulphur in some of the pyrite and of trace amounts of Co, Ni and Au. Some pyrite may be detrital, some may be authigenic and some introduced.Drab coloured rocks, uranium and sulphide mineralization, the presence of hydrocarbon (thucholite) and a post-Archean regolith formed under reducing conditions have been cited as evidence of an early Precambrian reducing environment extended to the atmosphere. Sedimentary features indicating fast-flowing water and possibly a cold climate imply that the uraninite would be exposed to whatever oxygen was present in the atmosphere under conditions which would inhibit complete solution. In the upper Huronian, red beds and in the Lorrain Formation a monazite - iron oxide assemblage and copper mineralization indicate more oxidizing conditions. . Similar uranium deposits occur at Agnew Lake and in the basal Huronian north of Sudbury there are minor uranium and gold values.Provenance, lack of complete oxidation, transportation and depositional processes, redistribution during diagenesis and possibly low grade metamorphism, and the lack of post-depositional destructive processes are the dominant factors in the formation and preservation of the ores. The modified placer theory of genesis is well entrenched and an exploration model for such deposits throughout the world is well-documented.Research continues on mineralogy and textures of the ores, detailed sedimentology of the ores and their host rocks, with particular emphasis on: provenance area, the influence of early Precambrian mineralization patterns on the mineralization present in the Huronian both in space and in time, fluvial sedimentation and diagenesis. Expansion and reopening of the mines of the Elliot Lake camp should facilitate further studies."

Jan 1, 1986

By P. Bissert, M. Klein, L. Yan, D. Yantek

"Mine Safety and Health Administration (MSHA) regulations require underground coal mines to use refuge alternatives (RAs) to provide a breathable air environment for 96 hrs. One of the main concerns with the use of mobile RAs is the heat and humidity buildup inside an RA. The accumulation of heat and humidity can result in miners suffering heat stress or even death. MSHA regulations require that the apparent temperature in a fully occupied RA must not exceed 95°F. To investigate this issue, the National Institute for Occupational Safety and Health (NIOSH) conducted testing on a 23-person tent-type RA in its Experimental Mine (EM) in a test area that was isolated from the mine ventilation system. The test results showed that the average measured air temperature within the RA increased by 9.4°C (17°F) and the relative humidity (RH) approached 94 %RH. The test results were used to benchmark a thermal simulation model of the tested RA. The validated thermal simulation model predicted the average air temperature inside the RA at the end of 96 hours to within 0.6°C (1.0°F) of the average measured air temperature. INTRODUCTION If an accident occurs in an underground coal mine, miners who fail to escape from the mine can enter an RA for protection from adverse conditions, such as high carbon monoxide levels. One of the main concerns with the use of mobile RAs is the potentially adverse thermal environment inside an RA from the metabolic heat of the occupants and the heat released by the carbon dioxide (CO2) scrubbing system. Moreover, the humidity within the RA will increase through occupants’ respiration and perspiration and from the chemical reaction within the CO2 scrubbing system. The accumulation of heat and humidity can result in miners suffering heat stress, heat stroke, or even death. In its 2007 report to Congress, the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) recommended that RAs should be designed to ensure that the internal apparent temperature (a temperature-humidity metric) in an occupied RA does not exceed 35°C (95°F). However, a standard method to determine compliance with this metric does not exist. The heat transfer process within and surrounding an RA is very complex, and is not easily defined analytically or experimentally. To investigate the related issues, OMSHR conducted heat and humidity testing on a 23-person tent-type RA in its Experimental Mine (EM) in a test area that was isolated from the mine ventilation system. During the testing, numerous parameters were measured: heat input to the chamber, the air temperature and relative humidity inside the RA, the air temperature in the mine, the mine strata temperatures versus depth, and the airflow inside and outside the chamber. The focus of this paper is on the temperature rise within an RA. TAITherm heat transfer analysis software was used to develop a thermal simulation model of the RA as it was tested in the mine, using the test results as the benchmark. Both sensible and latent heat were used in the test and the model."

Jan 1, 2016

By H. N. Dunning

A comprehensive research program designed to aid development of new and improved methods for more complete production of petroleum from partly depleted reservoirs is being conducted at the Bureau of Mines Petroleum Experiment Station, Bartlesville, Okla. Water flooding has accounted for much of the petroleum produced by secondary-recovery methods; however, a considerable portion of the crude oil commonly remains in place after water flooding has been terminated. In recent years the possibility of increasing the efficiency of water flooding by using surface-active additives has received wide attention. In general, the results of laboratory research have shown that use of detergents as water-flooding additives will reduce the residual petroleum in porous media (1).3/ Some less extensive field tests have supported this conclusion but have not been entirely conclusive (2). Later studies (3, 4) have given conflicting evidence as to the relative worth of detergent additives for water floods in water-wet (hydrophilic) or oil-wet (hydrophobic or lipophilic) reservoir materials. The results of these studies emphasize the need for a more complete understanding of the fundamental principles involved in displacing petroleum from reservoir surfaces by injected fluids. Accordingly, a comprehensive research program was initiated to investigate the practical and fundamental aspects of detergency in petroleum production.

Jan 1, 1953

By Howard K. Worner

"In a rewarding career spanning nearly two thirds of a century, the author has worked at the frontier of such diverse fields as the creep of metals, structure properties and production of novel dental and surgical materials, molten salt electrolysis for titanium production, greatly improving the productivity of large iron blast furnaces and of oxygen steelmaking. While each of these has given great satisfaction, special thrills have derived from the development of new methods for the continuous production or refining of both ferrous and non ferrous metals. A rewarding segment was the evolution of various aspects of WORCRA technology. Unfortunately, several of these inventions have been ""ahead of their time"". Introduction""I am greatly honoured by the convening of this meeting to recognise my contributions to pyrometallurgy. My appreciation is the greater because this is the third Howard Worner Symposium; the first took place in the University of Newcastle in 1988, close to my 75th birthday. It was arranged by the local branch of The Australasian Institute of Mining and Metallurgy with the theme, ""Frontiers in Pyrometallurgy"". The second was organised by the University of Wollongong in conjunction with the Australian Academy of Science and the Australian Academy of Technological Sciences and Engineering; it celebrated my 80th birthday and, at my request, covered a broad range of topics under the heading of ""Recent Advances in Science and Technology"". Now, this very international meeting on ""Injection in Pyrometallurgy"" has been convened by the G K Williams Co-operative Research Centre for Extractive Metallurgy in my alma mater. I am both delighted and honoured that the cosponsors are the TMS (USA) and ISIJ (Japan).Dr Madhu Nilmani consulted me about the field to be covered and I readily concurred because ""injection"" has been of keen interest to me since the beginning of the 1960s when I began my pioneering work on sequential oxygen (or air) injection into flowing streams for both refining of blast furnace hot metal to steel and for the continuous smelting-converting of copper and nickel."

Jan 1, 1996

By G Chitombo, A Perryman, A D. Campbell, J White, B Hollis

This paper describes the development and implementation of an optimisation tool developed as part of the Mass Mining Technology (MMT) Project. The tool, known as the SLC Schedule Optimiser, is capable of optimising the schedule of development and production activity for a sublevel cave, given a fixed draw strategy, for the life of the mine.This paper starts by describing the development and production scheduling problem for a sublevel cave, the geotechnical constraint that a schedule of activities must adhere to, and outlines the pre-existing manual planning procedures used to produce schedules.Following this, the paper then outlines the optimisation tool developed, describes the changes to the planning process it has enabled and finally quantifies the improvement to operations this tool has brought using Glencore’s Ernest Henry Mining Operations as a case study.CITATION:White, J, Perryman, A, Campbell, A D, Hollis, B and Chitombo, G, 2016. Life-of-mine development and production scheduling optimisation for sublevel cave operations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 133–138 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Terry B. Linde, William M. Dowall

The recently completed In-Pit Crushing and Conveying Project at Phelps Dodge's Morenci Mine is rated among the world's leading materials handling projects. The operation involves the crushing and transport of more than 109,000 tonnes per day of copper ore, utilizing regenerative conveyors capable of providing over 5.5 megawatts (7,000 hp) of equivalent electrical energy. This paper describes the key aspects of the project and includes: Original project objectives; System design criteria; System description; Optimization studies; Major design features; Equipment description; and System commissioning.

Jan 1, 1993

By R. K. W. Merkle, F. A. S. Reyneke, Z. Harris, P. W. J. Delport

The technological advancements in computing power in the last 30 years have enabled the practical visualization of complex geological environments in three-dimensional (3D) space. 3D models and their application in the mining industry are becoming increasingly important, for example, to identify future exploration areas and targets, for mineral assessment and evaluation, and prediction and planning of future drill-holes. However, acquiring borehole data is an expensive practice, with drilling programmes costing mining companies up to billions of dollars each year. Tighter financial constraints on exploration budgets result in more pressure being put on three-dimensional models to accurately identify future target areas. This article aims to evaluate the potential drilling success of simulated greenfield and brownfield exploration using a 3D geological model created of Leeuwpoort tin mine. These simulations investigate the probability of intersecting a mineralized zone of economic interest and evaluate how the probability is affected when the number of drill-holes and distance from a known intersection changes. Furthermore, these simulations attempt to obtain an indication for the minimum number of drill-holes required for a successful exploration campaign at the mine. The investigation also aims to establish a first-pass attempt towards developing a ‘favoured procedure’ for identifying potential exploration targets for tin deposits with geological and geochemical characteristics similar to Leeuwpoort. The results for the ‘favoured procedure’ established are statistically tested using the ‘bootstrapping’ method. By simulating various exploration scenarios, the study also emphasises the importance of predicting successful drilling, which aids in budgeting for drilling programmes as the minimum number of drillholes needed for a specific exploration project can be determined.

Feb 2, 2022

By Joseph T. Singewald

The term "titaniferous magnetite" is used to designate those magnetic ores of iron that carry more than 2 or 3 per cent of titanium. Large and easily workable deposits of these ores occur in different parts of the world, and have attracted attention for many years. Under present furnace practice, however, the smelting of these ores is both difficult and expensive, and for that reason they are not accepted by furnaces, so that the deposits are practically worthless. The problem of finding a feasible method of utilizing these ores has naturally been attractive, and numerous attempts have been made to solve it. Experiments to that end embrace two lines of investigation. The one that has been the more frequently tried is the elimination of the titanium from the ores, so as to make possible their smelting in the usual way. The other is the devising of a method of smelting by which titaniferous ores may be reduced as economically as are non-titaniferous ores. The former method involves a physical process, the latter a chemical process.

Jan 1, 1913

By AIME AIME

TO THE AMERICAN MINING CONGRESS. AMERICAN INSTITUTE OE MINING ENGINEERS. MINING AND METALLURGICAL SOCIETY OF AMERICA. The committee that makes this report was appointed at the meeting of the American Mining Congress, at Denver, Colo., in. November, 1906. The appointment had in view the drafting. of a law for the regulation of quarrying and metalliferous mining under the police laws of the States, with the hope that the uniform adoption of such a law could tend to reduce the number of accidents in mining. Since its. appointment, the committee has had' under serious and continuous consideration the matter with which it was charged. At the meetings 0f the American Mining Congress in 19o7, 1908 and 1909, it reported progress. At the meeting in 1909 it was authorized to present its report not only to the American Mining Congress, but also to the American Institute of Mining Engineers and the. Mining and Metallurgical Society of America, and to present its report in printed form during the interim between meetings of the American Mining Congress. The committee collected from the officials of the States of the Union copies of their mining laws. With the assistance of the Engineering and Mining Journal copies of the laws 0f Great Britain, the Transvaal, New South Wales, Victoria, Queensland, Western Australia, Tasmania, New aland, and certain European countries were also obtained. These laws were subjected to careful study. The first publication of the committee was a summary of the more important metalliferous mining laws 0f this country. Upon the basis of the existing laws of the States of the Union, Great Britain, and the English speaking colonies, a tentative draft. was prepared and printed in limited number in 1909, for convenience in securing the advice and criticism of a considerable number 0f persons engaged in the mining industry. In this way valuable suggestions were received. At the request of the chairman of this committee, Mr. Frederick L. Hoffman, statistician of the Prudential Insurance Company, of Newark, N. J., summarized and reviewed the available statistics of fatalities in metalliferous mining in the United States. Mr. Hoffman's report was published in the Engineering and Mining

Jan 10, 1910

By E. P. Gustafson

Demand by precious metals explorationists for cost effective means to target subsurface geologic structures worthy of evaluation by means of drilling has led to the use of the predictor-correlator technique. To locate polarizable targets, the predictor-a localized inhomogeneity in electrical properties-is placed at various locations in the computer-simulated subsurface region, and correlated with the potential distribution observed in the field. The correlation coefficient obtained is assigned to the subsurface location. IP targets are extracted by calculating a second correlation section based on higher-frequency illumination and subtracting it from the first. The locations of correlation difference correspond to the locations of polarizable mineralization.

Jan 1, 1989

The sixth international symposium on mining with fill nearly coincides with the 25th anniversary of the Jubilee Symposium on Mine Filling. That symposium, held in August 1973 in Mount Isa, in part to commemorate the 80th anniversary of The Australasian Institute of Mining and Metallurgy, was the first in what has turned out to be a very successful series of symposia. Subsequent symposia were held in Sudbury, Canada (1978), Lulea, Sweden (1983), Montreal, Canada (1989) and Johannesburg, South Africa (1993). The series of symposia has now become an established part of the mining industry calendar, and it will be interesting to see which country is given the honour, and accepts the challenge, to organise the next symposium.One way of predicting the future, or some small part of it, is to revisit where we have already been with a view to determining the existence of any trends that may impact on the future. An historical review of filling practice and research, with special emphasis on Australian experience in particular and worldwide in general over the previous 25 years, will enable me to address the historical and predictive objectives. Controversy can always be achieved by producing a best of list; it can be guaranteed that everyone will disagree with at least one of the nominations. On this occasion, the best contributions by individuals or groups in a number of areas of mine fill technology, over the last 25 years, will be the basis for the nominal awards. The controversy can be increased by posing a number of questions that, hopefully, some of the authors will address during their presentations. I imagine the social functions will be busy enough, but the questions may just add to the cut and thrust of the debate.

Jan 1, 1998

By R Schlueter, H Mischo

The mining industry is facing a variety of geological, technological and social challenges. Future deposits show a general tendency towards increasing depth with complex ores and decreasing grades. One promising approach to deal with low-grade ores is bioleaching in the form of heap and dump operations. Bioleaching is already a state-of-the-art technique, especially for the extraction of copper from sulfide ores. The next step in the development of this technology will be its application as an in situ technology. First attempts to adapt this technology in underground mining in the form of stoping and block caving have already been made. Both methods have to be carried out adjacent to conventional mining operations and therefore require much effort regarding drift development as well as extraction and transport. The adaption of bioleaching as a borehole mining method is the next step to establish an innovative in situ technique to meet future challenges.The Freiberg University of Mining and Technology established the Biohydrometallurgical Centre for Strategic Elements (BHMZ) to foster interdisciplinary research along the whole biohydrometallurgical process chain. In general, 13 different university institutes and several associated groups with about 30 PhD students are mainly focusing on the extraction of indium and germanium from deposits, tailings and recycling material. One of the core projects within the BHMZ is the design and implementation of an underground in situ bioleaching testing facility.This paper demonstrates the potential of in situ bioleaching under technological aspects. Furthermore, different conditioning methods to increase the permeability of the orebody will be explained, and the BHMZ’s underground testing facility will be presented.CITATION:Schlueter, R and Mischo, H, 2015. Potential and applications of underground in situ bioleaching, in Proceedings Third International Future Mining Conference, pp 205–212 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By Paul W. Johnson, Ralph C. Kirby, Frank A. Peters

A series of economic evaluations of processes for producing metallurgicalgrade alumina from low- grade aluminous materials is being conducted by the Bureau of Mines to determine the relative processing costs . The two processes considered in this evaluation are concerned with the recovery of alumina from clay through the formation of ammonium alum . In the first process , dehydrated clay is leached with ammonium bisulfate solution ; in the second process , clay is baked with ammonium sulfate and then leached with water containing a small quantity of sulfuric acid . After the alumina is dissolved by either of these methods , the iron is reduced to the ferrous state to avoid crystallization of ferric sulfate with the alum . The recovery of pure alum requires two crystallization steps . The alum crystals are then redissolved and precipitated with ammonia to produce alumina hydrate , which is calcined to a - alumina . These evaluations are based on published work , and the proposed plants are designed for a capacity of 1,000 tons of alumina per day . The estimated operating cost per ton of alumina for the bisulfate leaching process is $ 117.06 , and for the sulfate baking process , $ 109.26 . Using a Marshall and Stevens chemical equipment index basis of 240.0 , the estimated fixed capital costs , in the same order , are $ 158 million and $ 146 million . Under current economic conditions , these two processes are not competitive with the Bayer process for the production of alumina from bauxite . Since small improvements will not reduce costs sufficiently to approach competitive costs , future research work with these processes should be confined to areas likely to result in major cost reductions .

Jan 1, 1965