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By M. Misra, I. A. H. Schneider

The flocculation of -38 pm calcite, hematite and kaolinite aqueous suspensions by the yeast Candida parapsilosis and products derived from rupture of the microorganism was studied. Flocculation of hematite suspensions by the microorganism and its derivatives readily takes place between pH 2.8 and 11.4. Maximum flocculation occurs at about pH 6.5. Flocculation of calcite suspensions by the microorganism and its derivatives readily takes place between pH 7.0 and 11.8. Maximum flocculation occurs at about pH 10.0. Flocculation of kaolinite suspensions was less than that for the other two minerals. However, a soluble fraction derived from the rupture of the organism functioned as a good flocculant for the mineral, albeit at an increased concentration, between pH 2.6 and 11.5. Maximum flocculation occurs between pH 6.8 and 7.2. An attempt is made to relate the behavior of the various systems to the surface characteristics of the minerals and the surface and chemical properties of microorganism and its derivatives. Experimentation used to evaluate the flocculation includes actual flocculation tests, microelectrophoresis measurements and scanning electron microscopy.

Jan 1, 1994

By L. J. Barnes, R. O. Koch, J. H. Versteegh, P. J. H. Scheeren, F. J. Janssen

Following two years of laboratory research with bench scale reactors, a 9 m3 experimental process demonstration reactor was installed at Budelco's zinc refinery to treat their underlying groundwater. A 600-fold scale-up was successfully achieved. It has demonstrated that this anaerobic microbial process can remove a wide range of heavy metals and sulphate to the required levels. Extended operation of the demonstration unit has shown that the process is robust, can withstand wide variations in feed composition, rapidly recovers from operational upsets and is easy to start up and shut down. The metal sludge produced can be processed in a metal refinery to recover both metals and sulphur.

Jan 12, 1992

By Leonardo Zuchi Guio

A ArcelorMittal Tubarão vem trabalhando nos últimos dois anos na implantação de um sistema automatizado de julgamento da qualidade da superfície de bobinas laminadas a quente, juntamente com a ArcelorMittal Global R&D. Tal sistema é denominado CGSIS – Coil Grading Surface Inspection System – e tem a função de interpretar as ocorrências de defeitos superficiais, identificados por um sistema de inspeção automático através de câmeras CCD auxiliado por técnicas de visão artificial, à luz da necessidade requerida pela aplicação final do material. Todas as ações sugeridas pelo sistema são baseadas em regras de aplicação e nas informações obtidas do sistema de inspeção automático, requerendo para isso taxas de acerto de classificação de defeitos adequadas para uma boa tomada de decisão. Para tanto, várias melhorias foram necessárias, envolvendo questões de ambiente, desempenho, confiabilidade, disponibilidade e treinamento do sistema, para se obter com isso melhores níveis de detecção e acerto. Outras questões envolvidas em tal processo concernem às mudanças aplicadas a políticas já estabelecidas de julgamento e comunicação do novo sistema com os sistemas já existentes. Vários benefícios da implantação do projeto já estão sendo percebidos provenientes das etapas de preparação para a instalação e espera-se que após a operacionalização um ganho superior a R$320k entre redução de custo com pessoal, aproveitamento de material e redução de reclamações de clientes seja alcançado.

Jul 30, 2018

Is your company paying taxation on profits which are partly illusory?ò Are unions making wage demands based on erroneous notions of the real level of value added to your companyÆs production?ò Do you receive historic data on profit contributions by different products, or for different market areas, which you feel may be misstated?ò Do you find that cash is not always readily available to pay dividends out of reported earnings because, it is required to finance additional working capital without a real increase in the level of activity?ò Are your planning and budgeting routines hampered by the need to rely on historic financial data which bear little resemblance to what the future may hold for your company?ò Are you able to maintain your business at its optimum operating capability or do you feel each year that it becomes more and more difficult to achieve the same volumes of prdduction at the same level of return on assets employed without having to raise more capital?If your answer to any of these questions is "yes", then it is very likely that Current Cost Accounting (CCA) has something to offer you!characteristics of the mining industry and for single venture mining operations.

Jan 1, 1984

By Carl Belser

Approximately 30 million pounds of tungsten trioxide in the form of ferberite concentrates have been shipped from Boulder County. Since 1940, the production has varied considerably, being affected by the emergency needs of World War II and the Korean conflict. During World War II, attempts to stimulate production were made by the Metals Reserve Company by stabilizing the price for a specified period, the Reconstruction Finance Corporation by small mining development loans, and the Bureau of Mines and the Geological Survey, who cooperatively explored some of the district by surface and underground core drilling. During the Korean conflict and continuing through the first half of 1954) tungsten production was being stimulated by a Government-gauranteed price and by financial assistance loans under the Defense Production Act of 1950 to qualified operators of properties that have merited exploration. This combined program has increased production in Boulder County from about 1,900 pounds in 1949 to an estimated 383,000 pounds of tungsten trioxide in 1953. The 1953 production came from 67 properties. One of the problems confronting producers is the need for improved beneficiaton methods. Ores from the area have not been amenable to flotation concentration and gravity methods have resulted in poor recovery, often less than 70 percent.

Jan 1, 1955

By William F. Lawrence

Due to the immense volumes of municipal wastes that are generated in this nation every year, it has become imperative that effective measures be developed to utilize all or portions of these materials in a productive and efficient manner. Nany larger municipalities employ incineration to reduce the bulk of material to be removed to disposal sites: but, even after incineration, approximately one-fourth of the original waste material in the form of non-combustible residue and flyash remain. It has been found that the flyash fraction of the incinerator residue contains varying amounts of copper, silver, gold, aluminum, iron and titanium along with many other important metals. The serious loss of these natural resources contained within the flyash and the monetary expense of current disposal methods present a serious and rapidly increasing problem to the public and to the Federal Government. The growing emphasis upon environmental control, rapidly increasing urban population and "convenience packaging" 'with its attendant increased waste production has led to the initiation of a broad range of studies concerning municipal waste. For example, the U. S. Bureau of I-lines is investigating all aspects of the incineration of municipal waste under its solid waste disposal program.l "In-house" studies range from improved incinerator design to potential recovery and recycling of the various components within the incinerator residue. A major portion of the latter research is being performed at the U. S. Bureau of ;-lines, College Park, Maryland facility while grants for specific areas of study have been issued to several universities and research institutes. In addition, the Department of Health, Education and Welfare has supported programs examining the potential recovery of paper; glass, metals and other components of unincinerated refuse followed by disposal in sanitary landfills.

Jan 1, 1971

By Angelus S. C. Owili-Eger

Although the foundation of a unified treatment of fluid flow in variably saturated porous media was established more than seventy years ago, no serious attempt was made to develop it until the early 1970's. Ever since, a number of unsaturated-saturated numerical models have been reported in the literature. However, none of these models have treated multidimensional, multiphase flow in deforming media, parts of which may undergo extensive secondary fracturing. A situation such as this is not uncommon in coal mining operations in which the longwall method of extraction is employed. The present model has been structured to handle such physical systems. This paper presents the mathematical formulation, the numerical algorithm, and a further validation and evaluation of the modified model. The model treats a multiphase flow in a three- dimensional regime and handles mining excavations of complex and changing configurations.

Jan 1, 1980

By E. Ghali, J. F. Dorion

This paper presents the results of on-going investigations on the influence of corrosion on the performance of support systems in selected underground gold mines. Rock support is exposed to various conditions that can be aggressive. Samples of corroded support were analysed using SEM and photomicrography to determine the main corrosion forms. Tests are on-going in controlled corrosion chambers to qualify and quantify the impact of rock and minerals particles on steel corrosion. As more data become available these relationships can lead to useful information on the choice of support systems and reliable estimates of their longevity.

Jan 1, 2011

By Andrew Kerr

Overview of Presentation ? Introduction ? An historical context: From 1866 to the 21st century. ? Geological framework for iron ore in the region known as the ?Labrador Trough?. ? Producing iron-ore deposits of the Labrador City ? Wabush area, and near-future production from the Schefferville area. ? Exploration projects representing potential future production?.or expansion of the district. ? Some concluding remarks???

May 1, 2011

By R. Raby

During the 1980 decade, the rapid price increase for flake graphite has generated a high degree of interest for the discovery and the development of alternate occidental sources of supply in response to fluctuations in quality and availability from current producers. Alike many industrial minerals, graphite draws its complexity not only from its mineralogy and unique properties but also from the very large spectrum of industrial applications each calling for specific quality criterion. As new high technology uses are being developed, more rigid specifications will apply. Discovered during the latter part of 1988 by Mazarin inc., some 30 Km South of Fermont near the Quebec-Labrador border, the Lac Knife deposit was quickly identified as one of the world major long term alternate source of stable supply for this mineral. This paper also reviews the status of the project development as of late 1991, while updating previous papers published by Industrial Minerals1990 and Mining Magazine 1990.

Jan 1, 1992

By Jr. Koch

In the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) phase of its National Uranium Resource Evaluation (NURE) pro¬gram, the U.S. Department of Energy (DOE) samples about 1400 sites for stream sediments in each two-degree quadrangle of the National Topographic Nap Series (NTMS) and about 1200 sites for ground or stream water. Through a geological/statistical analysis, we find that NURE data are useful for assessing the uranium resources of the NTMS quadrangles. Our computer-implemented System for Uranium Resource Evaluation (SURE) calculates a score for each NTMS quadrangle based on the HSSR, geologic, and radiometric data; we score the four Colorado quadrangles--Pueblo, Montrose, Durango, and Trinidad--that comprise the study area. We interpret the scores in terms of geology and the known occurrences, which include the Hanson ore deposit with reserves of 30,000,000 lbs. U308 and the Pitch mine with reserves of 1,740,000 lbs. SURE depends in part on distinguishing mineralized or metalliferous granitoids from barren ones through "geochemical signatures."

Jan 1, 1980

By I T. Ross

Sampling drawpoints in block cave mines has been a contentious issue for many years. Doubts have been expressed as to the validity of the process used at most mines. This paper outlines the sampling practice commonly in use, discusses the resulting issues associated with reconciliation and drawpoint closure decisions. The paper also looks to the future and highlights issues for some block cave mining operations currently planned to have in the order of one thousand active drawpoints. It is likely that these operations will require a new approach to drawpoint sampling. There are several potential technologies currently available although some appear to be better suited than others to replace the current approaches. CITATION:Ross, I T, 2012. Sampling in block cave mines, in Proceedings Sampling 2012 , pp 81-86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By J. Loredo

Asturias, in Northwestern Spain, has an extensive mining history. As a result of these historical mine activities where operations have been usually developed with little control on effluents or emissions (environmental regulation of mining activity has only been introduced recently), pollution has been severe in some areas, specially in Hg abandoned mine sites, which constitute one of the major environmental problems related to mining. In many of these sites, materials stocked in spoil heaps can be considered as hazardous wastes because of their chemistry, content on ecotoxic elements and potentiality to spread these to the environment. In the humid climatological conditions of the region, water and wind eroded spoils are dispersed through the environment by different pathways and occasionally surrounding soils and waters are intensively affected by pollution. According to the environmental risks that these unreclaimed mine sites suppose for human beings and ecosystems, remedial options must be considered.

Jan 1, 2003

By H Utama, hi, A Suw

PT. Indo Muro Kencana (PT.IMK) is gold and silver mine located in Central Kalimantan province, Indonesia. Mining activities in PT.IMK is conducted in Bantian pit area by applying surface mining method and using combination of excavator and hauler (articulated dump truck and rigid haul truck) as the transportation for ore to the crushing plant and waste material to the waste dump. Current blasting practice is ore-waste blasting. Ore-waste blasting is the term where the ore and waste rock are blasted in the same blasting process. Blasting is conducted by using nonel initiation system. By multiple pits operation, monthly powder factor is varied from 0.23 kg/t to 0.27 kg/t. Emulsion blend with density 1.15 g/cc is used as bulk explosive. At this stage, the concept of geoblast is proposed as an engineering tool for Drill and Blast engineering practice in PT.IMK. In addition, there is a need to maintain rock fragmentation by blasting, to maintain monthly powder factor, and to maintain excavator’s productivity. Next, the concept of scaled depth of burial (Chiappetta and Treleven, 1997) and the concept of blastability index (Lilly, 1986) are proposed as geoblast’s tools to improve blasting practice in PT.IMK. It is expected that rock fragmentation by blasting, explosive consumption and excavator’s productivity will be maintained by integration of geoblast and drill and blast engineering. Furthermore, the objective of this paper is to integrate geoblast and drill and blast engineering in order to create an engineering guideline in PT.IMK. Additionally, blasting trials with air decking application is proposed in order to support the geoblast’s improvement. It is planned that these blasting trials will be conducted in 2022. In conclusion, it can be seen that integration of geoblast and D&B engineering in PT.IMK is relevant to improve current drill and blast current practice and applicable to maintain rock fragmentation by blasting.

Nov 29, 2022

By James McManus

The original analogue instrumentation at Lornex Mining Corporation to optimize the throughput by controlling the power drawn by the semi-autogenous mills was found to be inadequate because of the frequent changes in ore type. Although the trunnion bearing pressure of the mill was a crucial control criterion, it was not utilized in the original control scheme. After several plant tests of different types of analogue controllers were unsuccessful in finding any control equipment suitable for this application, it was concluded that a digital process control computer was required. Computer control strategy to optimize the grinding rate by controlling the power and the bearing pressure of the semi-autogenous mill was developed and a Fox 2 /30 computer made by Foxboro was selected. After six months of experimentation, it was found that the throughput was increased substantially by computer control.

Jan 1, 1978

By William G. Ryan, David S. Graham, Dan A. Brown, Rich A. Lamb, Paul J. Axtell

"The St. Croix River Crossing project on the Minnesota-Wisconsin border has been in the process of planning and public debate for two decades, with several changes in alignment. During the course of the earlier planning process in 1995, a drilled shaft load test was performed to obtain preliminary design information. There were some difficulties in maintaining stability within the weak sandstone bearing formation, and the measured axial resistance was relatively low. Subsequent experience by the Minnesota Department of Transportation with similar weak sandstones on the I-35W project suggests that improved construction techniques using modern drilling fluids may offer opportunities for improved performance. During final design in 2012 a second load test program was performed of a full scale test shaft constructed using polymer drilling fluids. The stability of the socket excavation in the weak sandstone appeared to be greatly improved and the measured axial resistance significantly higher.This case history illustrates the excellent performance that drilled shafts can provide in even relatively weak sandstone bedrock as well as the profound influence on axial resistance associated with the construction techniques used. The improved resistance values obtained by the new load test with more recent construction technology allowed the foundation scheme to be substantially optimized with respect to the number and size of required drilled shafts, reducing the size, cost, and risk of the coffercells and footings.IntroductionThe Minnesota Department of Transportation (MnDOT) has awarded the first phase of a bridge construction project that will cross the St. Croix River between Oak Park Heights, MN and St Joseph, WI. The first phase construction contract involves building the river pier substructures including groups of drilled shafts beneath each tower leg. A general location of the bridge project is provided in Figure 1.Prior to award of the construction contract, two separate design-phase axial load tests were performed on non-production drilled shafts with rock sockets. Both tests were static, bottom-up tests using the Osterberg Cell (O-cell). The first test was performed in 1995 when final design and construction was thought to be imminent. After years of public debate and literally, an act of Congress, design of the project was finally restarted and a second load test performed in 2012. The 1995 test was conducted on the Minnesota bank approximately 900 ft southwest of the St. Croix River bank. The 2012 test was conducted in the river about 2,100 ft northeast of the1995 test location. A plan-view of the project indicating the test program locations relative to the bridge alignment is provided in Figure 2."

Jan 1, 2015

By Waterhouse J. D, Harris B. M

This paper briefly describes the construction in 1979/80 of a 70m deep trial open pit coal mine near Bowmans S.A. and describes more fully the hydrogeological aspects of the exercise. The primary purpose of the Trial Pit was to provide a large sample (700 tonnes) of coal for combustion tests to be carried out in West Germany and the United States of America. Consideration was given to obtaining the sample of coal by drilling and by shaft sinking as alternatives to open pit methods. It was expected that economic mining of the deposit on an operational scale could only be achieved by open cut methods and it was recognised that major uncertainties existed in planning such a mine in the deep unconsolidated multi-aquifer deposit. It was therefore elected to obtain the bulk sample by constructing a trial open pit, which would be closely monitored to provide as much data as possible for future planning of a full scale mine. The dewatering of the Trial Pit was achieved using 26 deep pumping wells, assisted in the later stages by several hundred well points. This was probably the largest dewatering project currently in operation in Australia.

Jan 1, 1981

By Jessica E. Heuchan

An industry survey has been conducted by the Queen's University Mining Engineering Department of 30 Canadian mining organizations to determine how effectively newly graduated mining engineers meet the needs of the industry. The principal objectives of the survey were to evaluate, and thus provide focus on change for, curricula being taught at Canadian mining engineering schools in service of the industry's needs; to provide feedback on current industry expectations; and to reinforce contacts with the industry as a means of providing future collaboration. A strong focus of the survey was placed upon industry's perception of the special attributes of engineering hires and applicability of student academic training to meet their industrial requirements. In providing this detailed summary of corporate responses, a clearer understanding of the mining industry's expectations of engineering training at Canadian colleges and universities has been gained.

May 1, 2003

Orange Free State Branch Minutes of a Committee Meeting held in the Boardroom of Western Holdings on Thursday, IIth October, 1973, at 5.00 p.m. Present Messrs E. T. Wilson (in the Chair), E. Dunstan, W. B. Evans, C. J. Isaac, C. Mostert, N. Shand, R. Williams, and G. Young.

Jan 2, 1974

By M. C. Fuerstenau

A number of interesting and. important phenomena were revealed during a study of the response of beryl to sulfonate flotation (1). Perhaps the most important observation is the effect of various cations on flotation response. Experiments showed that in the vicinity of pH = 3. 0, about three ppm Fe.+++ increased recovery of leached beryl from about 60 to 100 per cent, whereas about four ppm Ca++ reduced the recovery from 60 to 2 per cent. With the exception of ferric iron, all of the other cations investigated reduced flotation recoveries drastically at this pH. As postulated in the paper "Sulfonate Flotation of Beryl", (1) even with low concentrations of polyvalent cations and sulfonate (on the order of one ppm), cation¬ sulfonates are precipitated immediately in solution. That is, blueish-white clouds .were noted to form after given additions of salts to. known solutions of sulfonate. Furthermore, it was also shown that one-hundred-fold more ferric iron than necessary to form the precipitated cloud had to be added to effect complete flotation. In other words, some form of solid ferric sulfonate was found to function as the collector in these systems. The form of the compound was suggested to be Fe (RSC3)2OH and that bonding to the surface occurs through the hydrogen of the hydroxyl. As the form of this compound was shown to be dependent on the extent of hydrolysis of ferric iron, it is to be expected that ferric iron will be unique in some pH region. Further, if the presence of hydroxyl in the neutral precipitated compound is of primary importance, then other cations should function similarly but at different values of pH, since they will hydrolyze at different concentrations of hydroxyl ion. To determine whether the premise of hydrolysis is correct, the study was extended to quartz systems lit the presence of various cations at various values of pH.

Jan 1, 1964