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By J. Organiscak

A majority of continuous mining machines employ a water spray system and a machine-mounted flooded-bed scrubber to suppress and capture dust during coal mining. These machine-mounted dust control systems must be designed to function within the localized face ventilation system at the mining section to control both dust and methane. Spray systems can impede or improve the scrubber effectiveness in controlling dust or methane at the mining face. Laboratory experiments were conducted to examine the effect of spray type, spray pressure, machine body blocking sprays and scrubber airflow on dust and gas levels, while using a 12.2-m (40-ft) exhaust ventilation curtain setback from the face. These experiments were conducted with the mining machine positioned at the end of a simulated 6.1-m (20-ft) sump and slab cut. Results indicate that the hollow cone nozzles with blocking sprays best complement the flooded-bed scrubber performance in an exhaust ventilation system. This external spray system notably reduced dust and gas levels on the off-curtain side of the mining machine for both the sump and slab cut compared to the flat spray nozzles. Higher scrubber airflows reduced dust and gas levels on the curtain side and in the return of the continuous mining machine. The remote operator position, located on the off-curtain side and parallel to the inlet end of the exhaust curtain, sustained the most stable and lowest dust levels around the mining machine.

Jan 1, 2010

By F. Nakhaei, M. Le Roux, Q. P. Campbell, S. Botlhoko

The results of coal sink and float tests are plotted as washability curves. Analysis of these curves indicates the most effective method by which the coal can be cleaned. Sink and float experiments are samplingdependent, destructive, and use toxic chemicals. The present research introduces an alternative method based on a 3D imaging system called RhoVol, in which the density of individual particles is determined from mass and volume measurements. A quantitative error analysis was conducted on coal sample density measurements obtained by RhoVol, and the main factors influencing the errors identified and investigated. The results show that the drawback of this technique is related to its not being able to detect hidden concavities in the particle, resulting in an overestimation of particle volume. Furthermore, it is difficult to capture the impact of porosity and cracks on the volume of coal particles obtained from 3D silhouette images. This mismatch between the RhoVol data and sink and float test results has led to attempts to apply neural network (NN) and linear regression techniques to produce a fully reliable model for correction and estimation of coal density. The NN approach offers superior predictive capability over linear regression, and the estimated density distribution is in line with the sink and float analysis. The root mean square error in estimation of density using the NN model was less than 0.05 g/cm³.

Aug 2, 2022

By M. Saghaeian, R. Hejazi, Fakoor Sanat Tehran Company, H. Abedini, M. Zare

"Dewatering of final tailings is one the biggest issues in iron ore processing plants. Because of the fine and hydrophilic particles in the iron ore tailings, dewatering of such material is difficult and, in most of the cases, needs to be processed using expensive and complicated equipment. In this study, a novel method based on classification of small and large particles has been proposed to improve the dewatering performance of iron ore tailings. In the proposed method, a hydrocyclone has first been used to separate the fine and coarse fraction of iron ore tailings. Then, the coarse fraction (hydrocyclone underflow) is easily dewatered by using vacuum belt filter. Then, the fine fraction (hydrocyclone overflow) is primarily dewatered by using a high rate thickener. Finally, the thickener underflow is added to the bed of solids on the same belt filter, which is used for dewatering of hydrocyclone underflow. The efficiency of this method has been compared with other solutions for tailings dewatering including changing vacuum filtration parameters, using fabric with larger pore size, and using pressure filtration, all through laboratory scale experiments on the tailings of an iron ore processing plant in Iran. The results indicated the superiority of this method compared to the other ones, which increased the specific filtration capacity of the tailings by around 46%.INTRODUCTIONWet beneficiation of minerals requires a substantial amount of water to enhance the efficiency of the process. Used water should be recovered at the end of process to minimize shipping costs, meet contract specifications, and reuse process water (Wills and Napier-Munn, 2006). Dewatering equipment is usually divided into sedimentation (thickening) and filtration (pressure and vacuum) equipment, the choice of which depends on particle size, solid content of slurry, and material nature (Mular et al., 2002)."

Jan 1, 2016

By R. Hurman Eric

The dew-point technique of activity measurements take advantage of the volatility of a component in solution. The pressure of the volatile component over a sample is determined from observations of the temperature at which condensation of the vapor occurs. The method is applicable best when the vapor pressure of the components would differ by about two to three orders of magnitude. Experimentally, this is a closed system involving the use of evacuated and sealed transparent quartz sample probes. Furthermore reliable vapor pressure data of the volatile component is essential along with a specialized high temperature furnace capable of giving reproducible results. In this context, the vertical Dew-Point Furnace (DPF) was designed and built after elaborate trails until enough proficiency was gained for reproducible results. Over the years the DPF was modified and improved. The DPF developed was versatile and could easily be used for activity measurements in the isopiestic mode (another method of measuring activities of a volatile component in a solution). The necessary ancillary systems; namely evacuation-flushing-evacuation followed by sealing of quartz sample probes under vacuum were also perfected over the years. As and when necessary the dew-point technique was supplemented by classical equilibration-quenching method employed on the sealed quartz sample probes to reveal necessary phase equilibrium information. The following were studied utilizing the above technique: (i) Activities in CU2S-PbS and FeS-PbS binaries and CU2S-FeS- PbS ternary at 1200°C; (ii) Activities in Cu2S-SnS and FeS-SnS binaries and Cu2S-FeS-SnS ternary at I200°C; (iii) Phase equilibria and thermodynamic in Cu-Pb-S, Fe-Pb-S, Fe-Sn-S, Cu-Sn-S and Ag-Sn-S systems. Most recently the following systems have been tackled: (i) Phase equilibria and thermodynamics in the Ag-Pb-S and Sn-Pb-S systems; and (ii) Activities in Ag2S-FeS-CuzS-PbS quaternary at 1200°C.

Jan 1, 2003

By Wolfgang Linden

One of the most important factors in successful electric steelmaking is the continuous observation of the process and the reaction to it. Traditional electric arc furnace control uses mainly direct controls which are based on the electric power input. Not considering the furnace conditions will necessarily lead to suboptimal operation in terms of energy consumption and productivity not fully utilized.The ARCCESS FEOS (Furnace Energy Optimization System) includes the simultaneous control of the transformer tap, impedance operating point, reactor tap, burner and carbon injection, and DRI charging control. FEOS has proven in practical operation benefits of high melting yields, no interruptions through switch offs in borderline temperature area, rapid reaction, reproducible and efficient electrical energy input and short power-on times.

Jul 30, 2018

By N. S. Dalal, X. Shi, V. Vallyathan

"Electron spin resonance (ESR) and cytotoxicity measurements were made on newly fractured silica to examine specifically the role of the fractured-induced, siliconbased radicals (Si· and SiO·), and silica-generated hydroxyl (·OH) radicals in the mechanism of the cell membrane damage by silica. The concentration of the Si· and SiO· radicals was controlled through decay processes, thermal annealing, and boiling, while that of the ·OH radicals was varied by using catalase, superoxide dismutase, KMnO4, Ha2seO3, ascorbic acid, and metal ions, and monitored via ESR spectroscopy. The dust's cytotozicity potential was evaluated by measuring the silica-induced hemolysis and also by determining lipid peroxidation (using linoleic acid). Prom the comparison of hemolysis and ESR results it is deduced that the radicals play little· or no role in the silica-induced hemolysis. However, the lipid peroxidation data indicate that the radicals might be involved in the initiation of an oxidative chain reaction leading to the macrophage membrane damage through lipid peroxidation. INTRODUCTIONThe biochemical mechanism of Quartz-related pneumoconiosis is still not fully understood. It is believed, nevertheless, that one event of primary importance is the perturbation of cell membranes by the dust particles (Allison et al., 1966; Allison and Harrow, 1971; Bateman et al., 1982; Parazzi, et al., 1968; Reiser and Last, 1979; Shi et al., 1989; Summerton et al., 1977). The ensuing cell-membrane damage unleashes certain lytic enzymes resulting in additional cell injury and eventual fibrosis (Nolan et al., 1981; Summerton et al., 1977). Thus considerable effort is currently being made towards the understanding of the processes by which quartz particles disrupt the membrane of a red blood cell (RBC) or a pulmonary alveolar macrophage (PAM). A simple but important method of evaluating the membrane damage potential of a dust is the hemolysis test (Harington et al., 1971). Even though this test is used routinely for screening dusts for their cytotoxicity potential, the biochemical mechanism underlying the cell lysis by many dusts, including quartz, is still controversial (Kilroe-Smith, 1974; Singh and Rahman, 1987), and this provided us the impetus for the present undertaking."

Jan 1, 1989

Hazardous waste has often very complicated chemical compositions in a variety of physical forms and is normally processed in rotary kiln incinerators. Due to large variations in waste types and difficulties in feed characterization, the complex transport processes within the incinerator are not well understood, and the incineration process meets challenges in a smooth operation, and expects various uncertainties in the process chemistry and emission control. For better understanding of the incineration process, simulation was carried out by using Computational Fluid-dynamics (CFD) to characterize temperature and species distribution in the incinerator. In order to catch certain aspects of thermal and chemical behavior, a novel approach is proposed to represent approximately the waste streams and the subsequent combustion process. Hazardous waste in various forms from an industrial-rotary-kiln waste incinerator is firstly converted to a hydrocarbon-based virtual fuel mixture with approximately the same HIC molar ratio and calorific value. The simulation of the combustion process of the simplified hazardous waste was proceeded with a combustion model. The distribution of temperature and chemical species especially the remaining CO in the system is preliminarily investigated. Distribution of CO concentration, as a good indicator of emission level for the incineration process, could be used to evaluate the emission control. The predicted temperature distribution has been compared with available measurement data from an operating rotary kiln waste incinerator at A VR-Chieme, in the Netherlands. Reasonable agreement has been reached between the measured and predicted temperature data. [n the next step, measurement of species distribution in the system is planned to further validate the combustion model.

Jan 1, 2003

By E. R. Hoskins

The Gulf Coast States ranging from South Texas to Alabama contain vast resources of lignite ranging in energy content from about 4000 to 7000 Btu/lb (as-received) with sulfur content ranging from about 0.5 to 2 percent. Currently, the strip mining rate is about 35 million tons per year in Texas and essentially zero in the other Gulf Coast states. Estimates of future mining rates are as high as 310 million tons per year by the year 2000 with 240 being in Texas. In this paper, we examine the life cycle of the surface mineable lignice based on the most recent estimates of surface mine recoverable resources with two scenarios. The first indicates that a 310 million tpy rate could be sustained for only 15 years while the second scenario suggests that the 310 million tpy could be sustained for 25 to 30 years. If lignite resources are required beyond those that are surface mineable, the deep basin lignite will be developed. Five strategies for developing deep basin lignite are discussed.

Jan 1, 1983

By J. Shahabpour

"Many porphyry copper deposits of the Kerman copper province in central Iran are associated with a consistent structurally con-trolled main drainage pattern, which is shown in this paper to be a useful regional prospecting tool in the search for new deposits. The main drainage trends also generally allow the distiction of high-grade (>0.2% Cu) from low-grade (<0.2% Cu) deposits. Topographic maps1:50 000 or geologic maps 1:100 000 have been found suitable for identification of promising drainages.IntroductionTrends of the main drainage systems transecting the high-grade porphyry copper deposits of the Kerman Region in Iran coincide with Quaternary age regional faults and fractures. Observation of such drainage trends can expedite regional evaluation prior to field examination. Thirty deposits located in the Kerman Region (Fig. 1) have been studied to identify common features that can be used for exploration purposes, especially for the first stage of regional exploration. A variety of field criteria are available for subsequent rapid field checking prior to trenching and more costly methods such as drilling, etc.Characteristic geomorphic features have been considered as aids in mineral exploration by many authors (e.g., Faniran, 1971; Piotrovski and Lubkashov, 1976; Verstappen, 1983). Clark et al. (1967) indicated the relationship between geomorphology and the supergene enrichment of copper in Atacama Desert, Chile, and correlated three periods of supergene enrichment with three periods of pediment disection. Seeland (1978) used fluvial drainage patterns for uranium and hydrocarbon exploration in the Wind River basin, Wyoming. Postolenko and Konopleva (1973) used the reconstruction of ancient valley systems for exploration of gold placers"

Jan 1, 1996

By C. C. Whittier

PLANS are well matured for the joint meeting of the Coal Division and the Ohio Section of the Institute at Columbus, Ohio, Oct. 27 and 28, at which a large attendance is expected. The proceedings for a day and a half will be devoted largely to the uses of coal, the program providing for two technical sessions in the auditorium of Battelle Memorial Institute (505 King Ave.) on Friday, and various plant inspec¬tions on Saturday morning. By way of diversion on Saturday afternoon arrangements have been made for attendance en bloc at the football game between Ohio State and Northwestern, 100 seats having been reserved for the game at $2.40 each-as long as they last. An inventory of the high lights of the meeting would be incomplete without reference to the informal banquet at the Deshler-Wallick hotel on Friday evening, for which Eli T. Conner, Chairman of the Coal Division, is down for a talk, and Howard N. Eavenson, Vice-president of the Institute, will be the principal speaker. The program in detail is as follows:

Jan 1, 1933

By A. S. Robb

SAMPLING of an ore-body is one of the fundamentals in its exploration, development, and exploitation. It is carried out to determine the gold value per ton of an ore-shoot and the probable gold output of the refinery. Sampling also places any broken ground in one of two classes, ore or waste. The value and importance of correct sampling has been shown repeatedly in the past. On the other hand, instances could be given where those in charge of mines have not believed in sampling, and the result has been the same in every case-disaster. This has in all probability been due to assuming that good-looking, well-mineralized rock was ore. Sampling in some form might have averted this misfortune. In this essay, only the method of sampling and the estimation of ore reserves is treated. All titles, figures, and values are fictitious. None of the illustrations can be directly applied to any portion of the Hollinger mine, except Figures 1 and 2, which are included with the special permission of the Canadian Mining Journal. METHODS OF SAMPLING Hollinger Consolidated Gold Mines, Limited, has, from the very beginning of operations, carried out an extensive system of sampling, and the results of this sampling have completely governed the whole mining programme. The Hollinger discovery was made in 1909 and prospecting and exploration of &apos;the surface began at once. Four men were given jobs as samplers and they sampled thoroughly all the outcrops and all bed-rock which could be exposed to view by removing the overburden. When shaft sinking began, samples were taken at two-foot intervals. In 1912, an underground gang of six samplers was organized, and the number was increased at a rate of about two men per year as the size and extent of the workings grew. No permanent record of sampling was kept until 1919, in which year an average of 11.6 men took 28,458 samples, cutting 113,894 feet of sample. From that time until the end of 1934, the average number of samplers varied, but the total number of samples cut, and the total footage sampled, increased.

Jan 1, 1937

By Robert W. Yokom

As the search for new sources of energy and minerals leads to more remote areas of the country - and the world - the need to plan for adequate housing and community facilities for the construction and operations workforces and their families takes on an importance equal to the mining and processing facilities themselves. A corollary to the need for planning is the increasingly crucial need for development companies to devise effective strategies for dealing with the local communities impacted by these projects. Experience has amply demonstrated the high price to be paid for failure to learn this lesson, a price measured in lost productivity, confrontation with local communities, labor turnover, mental health and other social and eocnomic problems. In Sweetwater, Wyoming, a new industrial activity caused the population to double from 18,000 to 36,000 between 1970 and 1974. During that period industrial productivity fell 25 to 40 percent, cost overruns on the principal new industrial facility exceeded 33 percent, annual employee turnover rates climbed above 100 percent, the local mental health clinic workload increased nine times and complaints to the local law enforcement agency increased 60 percent.

Jan 1, 1981

By Pierre Buteau

Peat/ands distribution in Canada is widely spread thoughout the country and corresponds to a wide spectrum of wetland habitats which overlay peat deposits. The development and the evolution ofpeat/ands and peat deposits are closely linked together, since the vegetal remains of the peat deposits originate from the peatland habitats, and the peatland habitats constitute a response to many factors, including the properties of the substrate, which are the peat deposits. Peat/ands are defined as waterlogged terrains where the production of plant materials usually exceeds the rate of decomposition. The underlying peat deposits consists of organic residues associated to peatland vegetation, more or less decomposed, built up and kept under anaerobic conditions. Peat/ands evolution and distribution are determined primarily by climatic factors, but also by the geomorphology and edaphic conditions. All of these create particular hydrodynamical environments which will vary according to different regional settings, and sequentially to an evolutive time frame.

Jan 1, 2001

By Ralph B. Stevens

INTRODUCTION Underground fires continue to be one of the most serious hazards to life and property in the mining industry. Although underground mines are analogous to high-rise buildings where persons are isolated from immediate escape or rescue, application of technology to locate and control fire hazards while still in their controllable state is slow to be implemented in underground mines. Even in large surface structures such as hotels, often only fire protection systems which meet minimal laws are implemented due to the high cost of adding extensive extinguishing systems, isolation barriers, alternate ventilation, escape routes and alarm systems. Incomplete and ineffective protection occasionally is evidenced where costs would not seem to be a factor, such as the $211 million MGM Grand Hotel fire November 21, 19801. Paramount in increasing fire safety and decreasing the threat of serious fire is early warning followed by proper decision analysis to perform the correct action. However, very complex fire situations can be produced in structures such as high-rise buildings and underground mines simply because of the distances between the numerous fire-potential locations and fire safe areas. Other complexities arise when normal activities occur that emit products of combustion signaling a fire condition to a sensitive fire/smoke sensor. For example, the operation of diesel equipment or the performance of regular blasting can produce combustion products that reach the sensitive alarm points of many sensors2. Smoke detectors for surface installations provide fire warning when occupants are at a distant location or when sleeping, thus greatly reducing injuries and property damage. However, when installed in the harsh environments of underground mines, fire and smoke detection equipment soon becomes inoperative, unreliable, or requires excessive maintenance. The U.S. Bureau of Mines has performed many studies and tests to improve fire and smoke protection for underground mine workers3. This paper describes several USBM safety programs which included in-mine testing with mine fire and smoke sensors, telemetry and instrumentation to develop recommendations for improving mine fire safety. It is hoped that the technology developed during these programs can be added to other programs to provide the mining industry with the necessary fire safety facts. By recognizing fire potentials and being provided with cost-effective, proven components that will perform reliably under the poor environmental conditions of mining, mine operators can provide protection for their working life and property equal to that which they provide for themselves and their families at home. The basis of this report is two USBM programs for fire protection in metal and nonmetal mines4,5 and one coal program6. The data was collected beginning in May 1974 and continuing through the present with underground tests of a South African fire system installed at Magma Mine in Superior, Arizona, and a computer-assisted, experimental system at Peabody Coal Mine in Pawnee, Illinois. The conduct of each program was as follows: • Define the problem and its magnitude in the industry • Develop concepts to solve or diminish the problem • Review available hardware or systems approaches to fit the concepts • Install and demonstrate the performance of a prototype system through fire tests in an operating mine. MINE FIRE FACTS Whether in coal or metal and nonmetal mines, the potential severity of fire hazard is directly related to location. As shown in Figure 1, fire in intake air at zones A, B, C or D can cause contamined air to route throughout the mine quickly if not detected, isolated or rerouted. Causes and location of former metal and nonmetal fires are represented in Table 1; the cause and location of fatalities and injuries is shown in Table 2. Coal-related fires and their impact on deaths and injuries are graphed in Figure 2; their locations are described in Table 37. Significantly the table shows that the hazard to personnel was three times greater for fires occurring in shaft or slope areas, and the percentage of deaths and injuries was four times that of other areas. Number of Persons Affected A 129-mine sample indicated that from 8 to 479 employees per shift work in underground metal and nonmetal mines, and that deeper mines have larger populations, as shown in Figure 3. Coal mining relates similar employment, and a 16-state sample of 670 mines employing at least 25 persons shows the distribution in Figure 4. Drift mines accounted for 58 percent of the sample but employ only 45 percent of the underground workers.

Jan 1, 1982

By Lynn B. Hales

Everywhere you turn today there are articles on artificial intelligence and the rapid emergence of expert systems. Expert systems form a class of software that has developed as a result of the large research effort to develop computers and software that think intelligently. By definition, an expert system is a computer program that contains the knowledge component of an expert skill, can offer intelligent advice and justify its line of reasoning. Expert systems can advise people on what actions to take and when, assist in the diagnosis of the physical condition of a human patient or piece of equipment, or even take actions without human guidance, as in process control applications. Expert systems can also explain the line of reasoning behind a particular piece of advice or query for information from the user. Expert systems can be used as advisors to newcomers in any field in which mastery is attained by many years of experience. They often can provide expertise more uniformly and rapidly than human experts. Expert systems can also provide a means of documenting expert knowledge and procedures and provide a common repository for a changing knowledge base. The expert system can represent the best expertise available, thought out in the absence of pressure situations. Each of these attributes or characteristics should be helpful in improving typical concentrator control systems.

Jan 1, 1987

By R Higashi, D Maruoka, T Murakami, Y Iwami

The ironmaking industry consumes a large amount of fossil fuel derived carbon as heat source, reducing agent of iron ores and carburising agent of reduced iron. Although the demand for drastic decrease of carbon dioxide emission, carbon is an essential element for smelting process of molten iron. The carbon recycling ironmaking process by circulating CO has been already proposed to achieve carbon neutrality. However, the production of molten hot metal is not considered in this process because sufficient amount of carbon does not dissolve in reduced iron by CO. Therefore, our group has suggested a new carbon recycling ironmaking process which can produce hot metal. In this process, free carbon and iron carbides produced by carbon deposition reaction using metallic iron as a catalyst are used. It is known that only Fe3C is obtained as iron carbide by using CO gas, however, Fe5C2 is also produced by adding H2 gas. The composite agglomerated with these carbonaceous materials and fine iron ore (Deposited Carbon-Iron oxide Composite: DCIC) is reduced and melted in a furnace. It is reported that Fe3C in DCIC accelerates the reduction reaction and melting of the composite. In this study, the effects of iron carbides and free carbon on the melting behaviour of DCIC are investigated. Fe3C, Fe5C2 and free carbon were produced by vapour deposition using porous iron whiskers and CO-CO2-H2 gas. These were agglomerated with hematite reagent at a certain ratio to prepare DCIC samples with and without Fe5C2. The samples were heated up to 1300°C in inert atmosphere. The DCIC containing Fe5C2 completely melted and iron nuggets were obtained after the experiment. This behaviour was not observed in the composite without Fe5C2. This indicates that using Fe5C2 is more preferable than Fe3C for molten iron production using DCIC.

Jun 19, 2024

By R. G. Johnston

Minerals have many uses in paint systems. These roles include use as primary and extender pigments, sheen control, film durability enhancement, and rheology control. These and other uses of minerals in paints, and the effects of mineral quality variations on coatings performance are discussed. As coatings performance requirements become more demanding, tighter consistency of important mineral properties, such as particle size distribution and purity, is becoming increasingly vital. Future directions of mineral use to meet projected environmental restrictions and performance demands on coatings, including the use of advanced minerals technologies, are examined.

Jan 1, 1993

By Y. Luo

Surface subsidence process due to underground coal mining often has the potential to cause problems to buried pipelines. In this paper, a technique for assessing the stress level on a subsidence-affected pipeline is introduced. The main contributors for the stresses on the pipelines are identified. Mitigation techniques for reducing the stress on the pipeline have been proposed and successfully tested.

Jan 1, 1997

By K H. Esbensen

Optimisation of a real-time at-line monitoring system for control of industrial granule coating quality is presented. The system is based on a fluorescence imaging system, because fluorescence originates in the interiors of enzyme granules but is significantly quenched by a polymer coating (which is needed due to environmental precautions). We have developed an image analytical system for direct prediction of coating quality, which is based on application of the Angle Measure Technique (AMT) for image complexity characterisation; AMT is briefly described. The first part of the presentation addresses pixel sampling strategies within a digital industrial image, inherent in application of AMT, in which the unfolded image is regarded as a one-dimensional object in analogy with 1D process sampling in Theory of Sampling (TOS). The effects of random, stratified and systematic pixel selections in the unfolded image are evaluated. Also factors such as the fraction of image pixels and the effects of specific unfolding strategies (there are three principal strategies, termed æchopÆ, æsnakeÆ and æspiralÆ respectively) are investigated. It turns out that unsuspected artifacts are sometimes produced, related to the specifics of the unfolding procedure, which interferes with a straightforward 1D TOS process sampling analogy. These artifacts have a wider interest û among others, for 2D sampling û and therefore receive special attention in this presentation. The optimal pixel selection strategy for the AMT algorithm is found to be systematic or stratified sampling (not surprising according to TOS) of 500+ initiating points, but need to be unfolded in the novel spiral- or snake-wise fashions in order to effectively counteract these artifacts. This also has a general impact on various suggested standard schemes for 2D grid-sampling, among others, from the geoscience realms. The second part of the presentation is directed towards optimal image analytical sampling of a continuous series of fluorescent images (imaging of conveyor belts of æinfinite lengthÆ), ie optimisation of process image sampling. The minimum number of images needed to uphold a sufficiently good on-line estimate of the quality control (QC) parameter in question is found to correspond to the relatively high sampling rate of 15 - 20 per cent, which can be shown to be related to an intrinsic very high measurement error level (25 per cent) of a mandated analytical reference method.

Jan 1, 2005

By L. Barnewold, A. Merchiers, M. Pütz, P. Jeschke, M. Dammers

The mining industry faces many difficult challenges, for example, lower ore grades, smaller and deeper deposits, and longer transportation distances. In the past, there have been remarkable innovations in both equipment and the types of mining methods for which it is used, which have resulted in economies of scale. This has led to an increased use of bulk mining methods, like sublevel and block caving, which has increased productivity and reduced costs. Haulage alone plays a major role. Current haulage techniques are a significant cost driver, which account for between 15 and 30% of the overall capital investment (capex) in a mine and are an increasingly part of the operating costs (opex). The paper introduces a simulation tool of main haulage system in underground mining. Therefore, performances and the costs of the three most common underground main haulage systems, rail, truck, and conveyor, are calculated using a developed modeling tool. The tool was applied and validated in a case study carried out with the LKAB Kiruna Mine in northern Sweden.