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By Whiten W. J

The control of mineral processing plants incorporates a number of off-line and on-line actions by plant personnel to obtain satisfactory plant performance. In general, off-line actions centre around intensive data analysis, while on-line activities are either automated control actions or prompted by qualitative interpretations of quantitative and qualitative information. Data sets obtained by various data logging devices and laboratory analysis of samples in many modem plants may be very large and are often unmanageable. This paper presents a method of analysing the data sets typically found in mineral processing, based on cluster analysis. The results of this analysis leads to a more complete understanding of operations in comparison with existing analysis tools used in mineral processing.Improved process configuration, optimised control strategies and in some cases, direct use of the results in monitoring process unit operations may be achieved.

Jan 1, 1992

Since first introduced, the coal mine roof rating (CMRR) has been widely accepted as a tool for geologic characterization and mine planning. This paper discusses the application of the CMRR to another practical ground-control problem: extended cuts. Extended cuts, i.e., cuts greater than 6 m (20 ft) in length, are commonly used with remote-control continuous miners. Extended cuts can greatly increase productivity, but they have been associated with a number of fatal roof-falls. When extended cuts are attempted in weak roof material, the roof may collapse before it can be bolted Until now, it has not been possible to predict where conditions may not be suitable for extended cuts. In this study, data on the CMRR and extended-cut experience were collected at 36 mines in seven of the United States. It was found that, when the CMRR was greater than 56, deep cuts were routine in nearly every case. When the CMRR was less than 37, extended cuts were almost never taken, and, when the CMRR was between 38 and 56, extended cuts were sometimes, but not always, feasible. The data also show that extended cuts are less likely to be stable if either the entry span or the depth of cover increases.

Jan 1, 2000

By J. A. Harrison

Most coal being used in the United States has been subjected to one or' more processes of coal preparation. The physical and chemical characteristics of a coal have a marked influence on the ultimate uses that coal may have. The selection of the proper preparation processes may similarly be important in producing the best practical coal product for any particular use. The physical composition and distribution of physical constituents in the coal will partially determine the efficiency of the preparation process chosen and conversely distribution and concentration of coal macerals will, to a degree, be controlled by the preparation process. A number of preparation processes have been evaluated to determine this interrelation. If a coal having' certain specifications is desired, these evaluations trill assist in providing information needed for the production of this coal.

Jan 1, 1962

By A. Mitura

The paper presents the initial investigation of possible energetic applications of chosen wastes from groups: 06, 03, 05 and 01, including coal slimes being secondary product of hard coal processing. These categories of wastes are catalogued according to the polish law, where 06 ? wastes from production, preparation, purchasing and application of products of non-organic chemistry; 03 ? wastes from wood processing and from plates and furniture, celluloid mass, paper and card board production; 13 ? oil wastes and wastes from liquid fuels; 01 ? wastes produced by searching, extracting, physical and chemical processing of ores and other mineral raw materials. The change of combustion heat value was evaluated in produced energetic mixtures containing these types of wastes together with the change of their individual components. All combinations of ingredients were taken into consideration giving 256 various mixtures, from which 36 were selected to investigation. This allowed the performance of statistical factor analysis. For such prepared materials the application of regressive method was proposed in purpose of calculating combustion heat value and then the comparison of empirically determined and theoretically calculated heat values was performed. The change of regressive coefficients can be determined by the nature of Hess law (eq. 1) what was investigated and the attempt of its explication and validation was done.

Aug 1, 2013

By Peter Silveston, Earl Shannon

Process-oriented experiments on the use of coal as an adsorbent for certain soluble components of sewage are described. The capacity of Canadian coals for these components was less than 0.1 per cent by weight for the highest concentration at which these components could be expected to be found in domestic sewage. This is much less than values reported in the past. A pronounced selectivity between components was observed. Experiments on bacteria removal in beds of coal, regeneration of spent coal to restore adsorption capacity and COD contributions of coal are reported in the paper. The simple application of coal as an adsorbent does not seem promising.

Jan 1, 1970

By M. Guo

Coal-based Direct Reduction in Interior-combustion Shaft Kiln (CDR/ISK) is a brand-new technique. Compared with the traditional Coal-based Direct Reduction (CDR) technique, its main character is to use Interior-combustion Shaft Kiln (ISK) as the reactor of direct reduction. After being crushed and grinded, iron ore is made into green pellet, which will be surface-coated by coal fines. Then, the surface-coated green pellet can be directly reduced in ISK. The pellet should not be too dry and should be charged from the top of ISK. Oxygen-contained air should be blasted into ISK to keep the temperature in it higher than 1000 degrees centigrade, at which iron oxide will start direct reduction. The reduced pellet will be discharged from the bottom of ISK and after de-surface-coated, spherical Direct Reduced Iron (DRI) can be gained. The volume of carbon monoxide in the off-gas discharged from ISK is less than one per cent. By using this technique to get one tonne DRI, the consumption of coal is about 300kg of fixed carbon, which is much lower than the energy consumption by using other CDR techniques. There is a lot of complex refractory iron ore in China, which remains unexploited. The iron-bearing minerals in this kind of the iron ore can not be beneficiated economically by present technique of gravity, magnetic, flotation or magnetic roasting because the iron minerals are too very finely disseminated to be liberated, or, the iron minerals are too similar to gangue to be separated each other. By using CDR/ISK, complex refractory iron ore can be directly reduced in lower temperature and all kinds of iron mineral can be turned into iron metal. As the grains of iron metal growing larger during direct reduction, magnetic separation can be used to separate iron metal from gangue mineral, thus high-grade iron metal fines can be gained. According to the experiments, the grade of iron metal fines is above 90 percent and the recovery of iron is higher than 90 percent. The consumption of coal to process one tonne of complex refractory iron ore is only about 90kg of fixed carbon.

Jan 1, 2014

By Michael D. Zuber

This paper discusses the use of a coalbed methane simulator that has been modified to account for the removal of grid blocks as a function of time to estimate gas emission and production for a variety of mine-associated problems. The specialized features of the simulator are presented. Example applications illustrate the models' use in estimating methane emission rates during mine roadway development, and estimation of longwall panel degasification by horizontal boreholes.

Jan 1, 1997

By J. M. Vonfeld, V. D. Hanson, W. K. Heinlein

TWO overfeed drum-type separators using a suspension of magnetite in water as the separating medium have been installed in the Champion No. 1 preparation plant of the Pittsburgh Coal Co., Division of the Pittsburgh Consolidation Coal Company. A simplified flow diagram of the Champion No. 1 coarse coal circuit is shown in Fig. 1. A railroad car rotary dump, capable of handling 20 cars per hr, discharges the coal into a hopper. Coal is fed from the hopper of the rotary dump to a 60-in. belt conveyor by two reciprocating pan-type feeders. The belt conveyor feeds the run of mine coal onto the main raw coal screen. The first deck is fitted with 3 in. round hole perforated plate which removes the 3x0-in. coal. The second deck of the screen is equipped with 6-in. lip screens which separate the remaining coal into +6 in. and 6x3 in. The +6 in. coal is transferred to a shaking picking table and then discharged onto the loading boom. The 6x3-in. coal is fed to the No. 2 dense medium vessel for cleaning. The clean coal from this unit flows to a vibrating screen where the medium is removed and the coal sized into 6x4 in. and 4x3 in. The 6x4-in. coal is transferred to the loading booms and the 4x3-in. is conveyed to the clean coal classifying screens to remove degradation. The 3x0-in. raw coal is blended in a system composed of three storage bins having a total capacity of 400 tons. From these bins the coal is fed onto a 48-in. flight conveyor by three reciprocating feeders. This flight conveyor delivers the coal to the Rheo plant. The 3x0-in. coal is then cleaned in two 48-in. Rheolaveur launders each equipped with two Rheo boxes. The first set of boxes removes a primary refuse and the second set produces a middling product which is recirculated in the launders. The cleaned coal and water overflows from the primary launders to two sizing and dewatering shaker screens where the water and - 3/8-in. coal are removed for further cleaning in the Rheo fine coal plant. The 3x3/8-in. clean coal is combined with the 4x3-in. coal from the No. 2 vessel, sized into 4x2 in., 2x1 1/4 in., and 11/4x3/8 in., then sent to the loading booms. The 3x0-in. refuse from the primary launders is normally fed to the No. 1 dense medium circuit, but any portion or all of this material can, as an alternate, be processed in the Rheo rewash launder. The primary refuse when fed to the dense medium circuit is screened into 3/8x0 which is cleaned in the fine coal plant and 3x3/8 for cleaning in the No. 1 vessel. The clean coal from this vessel is passed over a vibrating drainage and rinse screen, then sluiced to the rewash sizing shaker where it is dewatered and sized for loading. The installation of a pilot plant separating vessel using a suspension of magnetite in water was pro-

Jan 1, 1952

By Abdullah Arik

An ore reserve block model is the basis for various decisions in mine development and production. The block model is initially built using the information from the drillhole data only. Once the mine is put in operation, the information from the blasthole data becomes available. Since the spacing of the blastholes are much closer than the exploration drillholes, the blasthole data gathered from the mine over the years become quite extensive containing valuable information about the deposit. In practice, the information from the blastholes is the basis of determining the ore and waste boundaries between and within mining blocks. In an ore reserve model, the valuation of blocks on and close to the pit face can obviously be improved by using blasthole data from neat by drilled and mined-out blocks in addition to using the widely spaced drillhole data. The ideal basis on which to integrate blasthole and drillhole data is to use cokriging.

Jan 1, 1996

By M. Ghiani, R. Peretti, A. Zucca

The paper deals with the experimental application of a pilot flotation column to baryte and fluorspar ores. The column has been installed in parallel with the cleaning stages of two different industrial flotation plants where the above ores are processed using conventional cells with mechanical impellers. The effect of several parameters, including froth height, wash water additions, pulp feedrate and air supply rate, has been investigated. It has been shown that by finely tuning the above parameters good flotation performances can be achieved. The experimental results demonstrate the greater versatility of the column flotation and its superior separation efficiency, especially for the fine particle size fractions, over conventional cells.

Jan 1, 1995

By M. J. Fairweather, J. R. Egan, W. A. Meekel

Cominco Metals, in cooperation with two Canadian Universities and the Government of Canada, is developing applications for column flotation in the treatment of lead and zinc ores. Plant scale results at Polaris and pilot plant studies of Sullivan, Pine Point and Red Dog ores show column flotation to have significant advantages over conventional mechanical flotation for lead and zinc cleaning. Results from these ongoing studies are discussed in relation to ore texture, mineral recovery, impurity behaviour, scale-up and control.

Jan 1, 1988

By D. J. Murdock

Cominco Ltd. has developed a number of innovative technologies for electrowinning. The paper discusses the application of these technologies to the copper industry. Tankhouse and cell design will be discussed in addition to anode cleaning and cathode handling. Specific examples of the application of this technology to the copper industry are cited.

Jan 1, 1987

By R. Kahrger

This paper is written to convey the latest developments in compact bucket wheel excavators (BWE's) operating in medium-hard rock and will serve to indicate that BWE and compact machines in particular do in fact have application in materials other than loose sandy soils and soft rock. A recently run extensive three month field test in hard marl, which was previously considered too hard and difficult to be handled by a BWE, is used as an example to explain some of the design requirements and problems associated with digging harder materials.

Jan 1, 1990

By Vladimir Kislik

Competitive complexation/solvation theory of solvent extraction constitutes a general framework for interpretation and quantification of ion-molecular interaction data in extraction systems. Depending on extracting metal -- solvent affinity constant and metal concentration ratios, four possible stages of extraction behavior and interacting mechanisms, are considered. Affinity constant ratios are easily acceptable through the independent measurements of three-component systems. Once determined and tabulated, the affinity constant ratio data may be used in any system of interest. Mathematical descriptions of the results are introduced for different interactions. Active solvent (including water) concentrations in the organic phase and temperature are included to the quantitative consideration. The theory allows direct comparison of the complexing/solvating power (competition order) of various extractants, active solvents and diluents. As a result, predictions for the extraction effectiveness and selectivity are possible. Some metal extraction systems are analyzed on the base of the theory. Analysis gives a key for preliminary quantitative prediction of suitable extraction systems.

Jan 1, 2003

By A. K. Kyllo

The use of Composite Furnace Module cooling systems has been shown to give improved refractory performance in a number of above bath locations in WMC flash furnaces. To test the behaviour of modules in contact with a melt, a set of instrumented modules have been installed in the reaction shaft of a. nickel flash furnace. The location was chosen to provide a suitably harsh environment to ensure rigorous testing, while still allowing relatively easy access for module installation. The modules were continuously monitored to provide information on the module performance, as well as the temperature in the shaft itself. The shaft temperature showed significant transient behaviour, which resulted in heat fluxes through the modules ranging from 10 to 92 kW m-2. The modules were capable of handling the highest heat flux with no risk of the coolant boiling. This paper details the design and operation of the modules over a period of seven weeks.

Jan 1, 1999

By Xiaoming Wang

This paper describes a new magnetic separator integrating dynamic permanent magnetic force, gravity and flow dynamics to enhance the quality of the iron concentration. This equipment can increase the grade of concentrate by controlling the formation of magnetic agglomerations to reject most gangue. Test results indicates that the compound force field separator can be applied in improving the quality of iron concentrate and has a wide range of potential market applications. Keywords: magnetic separator, compound force field, rotating magnetic system, magnetite concentration

Sep 1, 2012

By Arun Appadurai

Pneumatic transport systems play a vital role in conveying discrete particles over a sizable distance with minimal energy consumption. However if such a system is not designed keeping particle physics in mind, it leads to intractable problems which could possibly assume dangerous proportions, including but not limited to expensive redesign of the entire system. This paper describes a novel method, which harnesses the powerful technique of Computational Fluid Dynamics (CFD) to investigate a problem occurring in rotary kilns using coal as a major fuel source. In some of the sites, a unique phenomenon of abnormally high CO emission was observed and owing to the highly random nature of occurrence, it was difficult to scientifically investigate the problem and its cause. Most of the published solutions for the high CO problem tend to concentrate on the incomplete combustion aspect of the kiln and resolve the situation by increasing the air supply thereby improving the stoichiometric ratio of combustion. This paper offers an alternate correlation that relates high CO emissions to the phenomenon of coal delivery fluctuations caused by the sub-standard operation of the coal transport system. A CFD model for the coal delivery pipe is validated by utilizing the actual process data sourced from the measurements taken from a functioning plant. The results of the model are used to derive correlative conditions that point to the unstable operating conditions of the coal delivery pipe prevalent in the industry. The conclusions are summarized into a series of recommendations for optimized design of coal delivery systems which are implemented in a pilot plant. The results irrevocably prove a statistically significant reduction in CO emissions without resorting to increased air supply and power consumption. Keywords:CFD, Pneumatic Conveying, Saltation Velocity, Particle Flow

Sep 1, 2012

By A. Martins, L. Goulart, E. Araujo, R. Batista, A. Costa e Silva

Steel cleanness is of great importance to the performance of almost all steel products. From very clean steel for bearings to long products used in civil construction, processing variables – in special those in steelmaking operations- must be properly balanced to achieve adequate cleanness for the desired performance. With the present complexity of steels as alloy systems, it is not efficient nor appropriate to develop these processes on empirical basis alone. Computational thermodynamics can greatly improve process development to achieve the desired cleanness level at reasonable costs. In this work, examples of these calculations and their applications to real steel processing are presented and discussed. The advantages, limitations and areas in which improvement in these calculations is desired are highlighted and discussed.

Jan 1, 2015

By Frank Sames

A recently developed model is used as a tool to optimize blast designs based on the continuing combination of full scale blast assessment and performance prediction. The use of this tool has allowed to evaluate present blasting practices and proposed designs through a better under-standing of the influence of the various blast parameters. The empirical model has a modular structure covering all aspects of blast performance including 30 fragmentation, potential rock damage and 30 muckpile profile prediction. The modules are assisted by a terrain model which is compatible to most mine mapping systems, and a blast design editor. The evaluation is summarized in a blast management module. Various studies have recently been undertaken using the model to qualify and improve blast designs with respect to wall stability, optimized fragmentation and muckpile distribution, as well as to the control of the environmental effects such as blast vibration and airblast overpressure. To verify the predictions of the modeling, full scale blast assessment techniques were used to qualify blast geometry, explosives and initiation performance, rock movement, muckpile distribution, near- and far-field vibration levels and airblast ovepressures. The model provides a tool to gain an improved understanding of blasting and blast control. The modeling results are presented in a visual form which allows simple comparisons of proposed blast designs. Additionally, the model can be used for detailed analysis and blast management.

Jan 1, 1996

By Jones J. P, Arriagada J, Scherpenisse C. R

A recently-developed model is used as a tool to optimise the design of blasts used to create final walls in large open pit mines. The use of this tool has allowed present blasting practice and proposed designs to be evaluated to predict the likely extent of rock damage behind the final wall. The evaluation of the damage is dependent on the predominant local geology. Modelling of damage using the software allows the potential zones of rock damage to be evaluated under the following criteria: I . the extent of new fractures formed in the intact rock mass; and 2. the distance to which dilation and extension of existing discontinuities and pre-existing fractures will likely occur. The computer model has been used to examine present blasting practice and to estimate the damage induced by final and intermediate rows of blastholes. The results of current practices are presented in a visual form that allows simple comparisons to be made for any proposed changes in design. To confirm the predictions of the modelling, physical measurements are being undertaken at selected mines to quantify damage behind blast patterns, and experimental programs are underway to measure near-field vibration, or shock, levels. The computer modelling software is being used to qualify and improve the design of final rock slopes in large surface mining excavations, and to provide site engineers with well-defined design criteria for consistency in design. The model is seen to be just one of many tools which are being used in large open cut mining operations to gain an improved understanding of blasting and blast control.

Jan 1, 1995