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By Wen L. Cai

This paper examines the effects of different block dimensions and cone bases on the economic open pit limit design based on case studies on a coal deposit consisted of two west- east elongated, near vertical thin seams starting with a base model dimension of 200x170x50 (NX*NY*NZ) with a block dimension of 10mx5mx4m (DX*DY*DZ), the blocks were combined along easting, northing and elevation directions. Two cone bases were used, one with a base radius of 10 meters, the other with a base radius of 0. Two pit design algorithms, one is the floating cone algorithm, the other is an optimum algorithm, were used to see which one of the two pit design algorithms is more sensitive to block dimension and cone base variations. The results are presented and analyzed.

Jan 1, 1992

By Michael Li

Unsaturated flow and solute transport were studied in three large columns measuring 1.5 m diameter x 2 m height, loaded with up to 3.7 t of oxidised waste rock, which was excavated from the Stratmat pile at Heath Steele Division, Noranda Inc. and contained elevated concentrations of zinc in the pore water. The bottom of each column was partitioned into 37 squares, each of which was drained independently. Following rain simulations at the top of the rock bed, the drainage in each drain port was monitored for volume and physicochemical parameters at pre-determined intervals. This paper describes some of the observations resulting from the experiments. The main conclusion of the study is that unsaturated flows in waste rock are heterogeneous, and flow channelling is ubiquitous. The results imply that the transport of solutes from oxidised waste rock to its toe drainage is subject to various controlling mechanisms, including geochemical equilibrium control and successive pore water dilution control.

Jan 1, 2000

By Xiyu Gao, Yi Yang, Mark I. Pownceby, Shuiping Zhong, Miao Chen

In the present study, X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray absorption near edge structure (XANES) spectroscopy, and Raman spectroscopy were used to investigate the effect of chloride ions on chalcopyrite bioleaching and chemical leaching at 25 °C. The leaching results show that the addition of chloride ions suppressed the dissolution of chalcopyrite in both chemical and bacterial leaching. In chemical leaching, the solution redox potential in the experiment without Cl− stayed in a range more suitable for chalcopyrite dissolution compared with experiments with Cl− . In bioleaching, the bacteria activity was suppressed by Cl− leading to low dissolution rates of Cu. Surface morphology and chemical speciation studies confirmed the formation of potassium jarosite on the surface of the chalcopyrite leach residues. In addition, S K-edge XANES indicated the formation of trace amount of elemental sulfur and covellite on the mineral surfaces.

By William C. Grady

The environmental and economic problem created by pyrite in coal are well documented. The removal of pyritic sulfur prior to, or during, utilization has been the object of considerable research, however, much of this research has proceeded without a proper knowledge of the microscopic occurrences of pyrite in coal. This paper investigates the forms, occurrences, and variations in the distribution of pyrite in major West Virginia coal scan. Twenty-nine samples from twenty-two major west Virginia coal scans were selected for this study (see Table I). The samples were selected so as to be representative of the major coal producing areas of the state. All samples, except five, were collected at active surface mines, as indicated in Table I, and all except one were channel samples. The time interval between sampling and preparation of polished microblocks varied from two months to two years, though most were prepared within three months of collection. Grinding, screen¬ing, and riffling of samples to obtain 250 grams of -20 mesh coal for microscopic analysis strictly followed ASTM procedure D2013-72.

Jan 1, 1976

By Y. Topkaya, R. E. Johnson, B. R. Palmer, Jia-Jun Ke, Da-Ping Kang

The kinetics of the leaching of antimony oxide ore (Sb2O4) in aqueous hydrochloric acid solutions has been investigated. This dissolution reaction is a heterogeneous solid-liquid reaction. It has been found that the leaching temperature and the concentration of hydrochloric acid turn out to be the significant influencing factors on the leaching rate. The apparent activation energy for the leaching reaction was determined to be 63.5 W/mol within the experimental temperature region of 50O to 90O C. The experimental results indicate that the leaching process is controlled by the rate of the chemical reaction.

Jan 1, 1993

An open pit production planning method for stage mining is presented in this paper. The method brings solutions to the four most important parameters in stage mining : 1) the number of stages, 2) the size and geometry of each stage pit, 3) the mining sequence of the benches in the stage pits, and 4) the time of transition from one stage to the next. The method can also simultaneously optimize the ultimate pit, mine life, and production rate in each stage.

Jan 1, 1996

By M. H. H. Mahmoud, T. A. El-Barbary, E. A. Abdel Aal, I. A. Ibrahim, A. K. Ismail

Fertilizer-grade phosphoric acid with a P2O5 concentration of 50% should contain less than 1.5% Fe2O3, otherwise, the P2O5 water solubility of the fertilizers prepared from high-iron acids will be low. High-iron Egyptian phosphate concentrates fromAbu-Tartur and Sebaiya- West were leached with sulfuric acid and recycled phosphoric acid to produce 50%-P2O5 phosphoric acids containing 4.0% and 2.7% Fe2O3, respectively. The high iron contents were reduced to the industrially accepted limit of 1.5% Fe2O3 by precipitation with potassium sulfate. The factors affecting the effi¬ciency of the precipitation process, e.g., temperature, time and K2O/Fe2O3 ratio, were systematically studied, and the optimum conditions were achieved. The clarification of the prepared phosphoric acid from iron-containing sludges was also investigated by varying the time and temperature. The utilization of the separated sludges as fertilizer and recovery of P205 by pulping in water were also evaluated.

Jan 1, 2000

By H. K. Lin

The free-milling ore characteristics of the Fort Knox gold deposit are ideal for studying gold and silver behaviors in various processing circuits without serious interference of sulfide minerals and other refractory factors. A galvanic effect leads to faster silver dissolution than gold dissolution and, as a result, the Au/Ag solution concentration ratio increases through the leach circuit. In the CIP circuit, Au adsorption is more effective than Ag adsorption. The Au/Ag solution concentration ratio decreases from 10.0 to 1.0 as the slurry advances from CIP tank #1 to CIP tank #5, while Au/Ag ratio in the carbon increases from 3.2 to 15.3, as the carbon advances from CIP tank #5 to CIP tank #1. Silver is stripped more effectively than gold from the loaded carbon. The Au/Ag ratio in solution reaches 2.0 in the first 75,700 L of strip solution that pass through the loaded carbon; as the stripping process continues, the Au/Ag ratio in the strip solution increases. In the electrowinning circuit, the Au/Ag ratio in the spent electrowinning solution is significantly lower than that in the electrowinning feed, indicating that Au is more rapidly deposited onto the cathode than Ag.

Jan 1, 2010

By D. L. Madge

The text of this chapter was not received in time for printing.

Jan 1, 1979

By A. J. Surtees, M. P. Evans

This paper discusses the development and application of sophisticated monitoring equipment used to measure the operating parameters of conveyor systems. With the radical reduction in price of computer hard- ware and software during the last decade and an associated increase in memory capacity, the concept of continuous conveyor monitor is now a reality. With this tool, the various problems normally encountered in large conveyor installations can now be avoided at an early stage. • The four main areas of application are: • Design verification • Hand-over certification • Preventative maintenance and increase of system availability Failure analysis The paper introduces the techniques used and gives examples where the service has been used.

Jan 1, 1996

By G. V. Krishna Roa, G. Vijaya Kumar

One of the main objectives while planning ventilation systems for mines with multiple fans is minimization of the total airpower consumption of the mine. Solution of this problem by conventional ventilation network analysis programs is tedious and time consuming, and may not yield optimum results in all the cases. The paper presents an algorithm for solving multiple fan networks by finding optimum combination of fan operating points for required airflow distribution in the ventilation system.

Jan 1, 1995

By J. Yordan, J. Zinterer

Effective removal of ink particles by froth flotation is of up-most importance in paper recycling. In this study, the potential use of talc particles as carriers of difficult-to-float fine ink particles is investigated. In order to accomplish ink particles removal, the interactions between talc and oily- ink particles in aqueous solutions containing flotation chemicals was studied by zeta potential distribution measurements and with the impinging jet apparatus. The chemical conditions under which talc-ink adhesion occurs are identified and reported.

Jan 1, 2003

By D. Gill, R. Burgess, B. Kyslinger

"There is always a demand in the mining industry to improve the safety and efficiency of roof bolting. Since 2008, Anglo American and Fletcher® have been working together to develop a new roof bolter concept that is safer and more ergonomic while maintaining current production rates. The recognized types of machines currently used in South Africa are always under constant review for improvement; however, there are limitations to the current design. The majority of the machines in South Africa are the “Man in Position” roof bolters. There are currently over 200 of these roof bolters in South Africa, with the bulk of the machines being twin-boom units. When operated correctly, these machines are safe, versatile, reliable and productive. However, with the operators located close to the drilling and bolting operations, they can be exposed to operational hazards. In addition, the major amount of material handling can be quite difficult on an operator. Anglo American, with a desire to improve safety, approached Fletcher to develop a remote style machine with simplified controls that maintained the productivity of the twin-boom machines. After several prototypes, the current model was developed. The chassis was designed for better operator comfort. A dual mast drill module was implemented to reduce the total time to bolt a cut. A remote operator’s station was incorporated to remove the operator from the front of the machine. The design was all about producing a safe and ergonomic machine from front to rear. This paper will explain the evolution and technological advancements from earlier prototypes to the current production machine. INTRODUCTION With mining, especially coal extraction, comes the necessity of supporting the roof. Since the 1950’s, the primary method for roof support has been the use of roof bolts. Roof bolting is considered one of the most hazardous jobs in underground coal mining. In 2004, there were 3,405 injuries reported to MSHA (Mine Safety and Health Administration). Of those injuries, 17 percent were associated with bolting machines (593 injuries). The majority of the injuries resulted from rock falling from supported roof. However, injuries involving a part of the body being struck by, or caught between, during bolting and drilling occurred with relatively high frequency (Burgess and Steiner). Roof drilling and bolt installation is labor intensive and repetitive. These labor intensive and repetitive requirements can lead to cumulative trauma. Operators are expected to perform a considerable amount of lifting, carrying, bending, reaching and stretching. Back and shoulders become sore from bending and twisting to install bolts or lift and position drill steels, wrenches and bolts. Confined operator spaces also contribute to difficult and awkward working positions for the operators (Cornelius and Turin)."

Jan 1, 2017

By Dennis K. Mortensen

Improvements in flotation technology are continually being made in the attempt to achieve the mineral processor's goal of maximum mineral concentrate grade and recovery at zero cost. Technology that cannot be totally proven in the laboratory must be tested under plant conditions either in a pilot plant or in the existing circuit. Problems associated with new technology can be solved effectively by the mineral processor who approaches each of the problems objectively.

Jan 1, 1989

By Huo Zuzhao

The main feature of caving methods is to draw ore from the overlying waste rock. Research on the movements of ore and waste plays a very important part in reducing ore loss and dilution and raising the economic benefits. This paper gives the basic theory of computer simulation of ore-draw, exposses the physical significance of mathematical model, puts forword a new formula of similarity characteristic value, brings forth a method of adjusting similarity, introduces the major functions of the simulation program and describes the ore draw control and stope parameter selection through computer simulation.

Jan 1, 1986

By P. R. Taylor

This work is concerned with the extraction of refractory metals using an electro-reduction process, in which a molten oxide melt, instead of halide, is used as the electrolyte. The process may provide an alternative method of producing refractory metals from their ores through use of a reverse-polarity direct current (DC) plasma arc heating process. In such a process, the plasma torch itself acts as an anode, and resulting liquid or solid product metals work as a cathode, whereas the molten oxide melt plays the role of an electron transfer layer. The focus of this study is: the electro-reduction of scheelite; vanadium pentoxide; and chromite. For the vanadium pentoxide, the proposed melt is mainly composed of CaO-V2O5/Li2O-B2O3-V2O5or FeO-CaO-SiO2-V2O5-Li2O with the addition of other alkali and alkaline metal oxides. In the case of scheelite ore, the SiO2-CaO-Li2O-WO3system is used as melt and metal aluminum or nickel could be used as a collecting media. As for the reduction of chromite ore, SiO2-CaO-Cr2O3-Li2O system with trace amount of CaF2is used as the melt. As a demonstration, chromium was successfully produced at a laboratory scale through the plasma driven electro-reduction process. One of the studied slags had a composition of 13.8% CaO; 4.9%CaF2; 36.4% Cr2O3; 6.9% Li2O; and 38.0% SiO2. Two observations are significant in this laboratory scale study. The first one was that the amount of Cr2O3and FeO, which were predominantly electronic conductors in the oxide melt, greatly affected the conducting mechanism of the melt. With high concentration of Cr2O3and FeO in the melt, the current efficiency was fairly low. In this case, chromium was found to be barely reduced because of electronic conducting mechanism. For example, with initial slag of 60% Cr2O3, no chromium was found reduced. With low concentration of Cr2O3and FeO in the studied melt, typically no more than 30% Cr2O3, it was observed that chromium was readily reduced due to the dominant ionic conducting mechanism. The second observation was that the addition of SiO2tothe melt helped to make the oxide melt more ionic, which was apparently desirable to the molten oxide electrolysis. However, high content of silica had a negative effect on the fluidity of the melt. This was resolved by adding trace amounts of CaF2to the melt. Therefore, by judicious selection of oxide melt, refractory metal oxides might be dissolved into it and yet the melt itself retains the required ionicity. A reverse-polarity DC plasma driven molten oxide electrolysis may prove to be a viable alternative route for the extractive metallurgy of refractory metals.

Jan 1, 2003

By Trevor R. Ellis

In August 2011, the Southern African Institute of Mining and Metallurgy (SAIMM) contacted mining institutes and related societies internationally to assess their interest in participating in coordination of the review of the South African Code for Mineral Valuation (SAMVAL) with reviews of other mineral valuation standards. The main mineral valuation standards are the CIMVal Standard of The Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the VALMIN Code of The Australasian Institute of Mining and Metallurgy (AusIMM), the SAMVAL Code, and the extractive industries? guidance note of the International Valuation Standards Council (IVSC), Valuation of Properties in the Extractive Industries, GN 14, designed for application within the full set of International Valuation Standards (IVSs). By January 2012, SAIMM had concluded that the level of respondent interest was adequate to organize a meeting. A meeting was scheduled for April 18, 2012 in Brisbane, Australia in conjunction with a VALMIN mineral valuation conference organized by the AusIMM. The stated purpose of the meeting was to develop an accord on terms of reference for pursuing harmonization of mineral asset valuation standards adopted by the participating mineral institutes. SME decided that, although it has not developed its own mineral valuation standard, it should participate in the Brisbane meeting and the harmonization process, as also did the American Institute of Minerals Appraisers (AIMA).

Jan 1, 2012

By Jan M. Mutmansky, David R. Kalasky

Computer simulation continues to be one of the most successful analytical applications of computers in the mining and mineral processing industries throughout the world. Through simulation, managers and engineers can explore the impact of new technologies, equipment designs, plans and operating strategies to improve their operations. It is not uncommon for a single simulation application to provide a quick payback of analysis expenses (within weeks or months) yielding long-term financial and operational dividends. The paper will present a summary of the types of software systems that are available for use on PCs and other computer systems. Support software for curve fitting, statistical analysis, and optimization of simulation models will also be presented. Methods of leveraging simulation efforts through networking and coupling of software systems will be discussed. Finally, the trends in simulation in the mineral industries will be analyzed. Areas of strength and weakness of simulation will be discussed along with the usefulness of commercial general-purpose and custom-writ- ten simulation packages. The future possibilities for simulation in the mineral industries will be outlined and predictions on trends for the future will be presented.

Jan 1, 1996

By K. V. Raj, T. Bhowmick

"Computational fluid dynamics (CFD) modeling of an open-pit mine has several challenges. A good quality mesh of the model domain is a pre-requisite for convergence in solution. Good quality tetrahedral meshing and insertion of prism layers in faceted open-pit mine geometry is complicated due to presence of numerous vertices and ridges. Presence of vertices and ridges result in poor quality tetra elements and holes in prism layers, which cause instability in the model. Good quality pit bottom prism mesh elements significantly improve the formation of velocity boundary layer and thermal boundary layer at the pit bottom. This results in an expected temperature dependent micrometeorological buoyancy flow in the pit. Whereas, model geometry without a prism layer, results in abrupt temperature gradient near pit bottom. Buoyancy flow and recirculation have significant effect in lifting mechanism of fugitive dust particles generated near pit bottom. Representative initial and boundary conditions and selection of appropriate turbulence model have significant influences on the simulation results. In this paper, three-dimensional models of open-pit mines are developed using commercial CFD software (CRADLE-CFD). Important constraints and various consequences in modeling complex open-pit geometries are presented. INTRODUCTION Application of Computational fluid dynamics (CFD) to model an open-pit mine to predict fugitive dust and pollutant concentrations in and around a mine is relatively new. In former Soviet republic (USSR), Baklanov [1] and Belousov [2, 3] presented numerical models of pollutant transport in open-pit mines in Arctic regions. In recent years, advances in mathematical and computational fields have enabled better modeling of pollutant dispersion phenomenon around mines using computational fluid dynamics (CFD). Several CFD software packages have been used by various researchers to model the pollutant transport in open-pit mines. Works by Alvarez et al. [4]; Lowndes et al. [5]; Silvester et al. [6]; Torno et al. [7]; Choudhury and Bandopadhyay [8]; Collingwood et al. [9]; Raj et al. [10] and Flores et al. [11]; are examples of application of various commercial and open source CFD packages (COMSOL, ANSYS, OpenFOAM) to model pollutant transport in open-pit mines. These researches provided a strong background for additional research involving CFD modeling of open-pit mines. Due to the limitations of computational times and capacity, 3D modeling and various aspects of fugitive dust dispersion in open-pit mines remained unexplored."

Jan 1, 2015

By Jurgen Weissflog

Why, where and since when using shiftable conveyors? Advantages of this equipment The ever increasing demand for bulk materials such as ore, coal, lignite, oilsand, oilshale and bauxite requires mainly an opencast operation. To exploit these materials huge amounts of overburden and partings must be transportes by means of conveyors, trucks or trains. When analyzing the various opencast mines it can be established that there exist only two basic types of mining systems, i. e., the discontinuous strip mining system as used in the USA (Fig. 1) and the continuous mining system as is commonly applied in Europe. The reason why these two mining methods have been developed parallel to and independently of each other to such a high technical standard results from the varying geological conditions of the mineral deposits.

Jan 1, 1983