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By W. J. Nosek

Reserve Mining Company completed construction on a major process modification project in June of 1980. These modifications enabled Reserve to reduce and control its final iron ore pellet silica content from 9.0 20.77 percent to 5.0 50.26 percent. The paper outlines the implementation of neutron activation on-line analysis and associated computer control loops for measuring and closely controlling the silica content of the iron ore concentrate at Reserve Mining Company. It contains a general overview of Reserve's taconite processing facilities and a presentation of the theory and operation of the neutron activation analysis equipment coupled with the computer silica control loops.

Jan 1, 1983

By W. Z. Choi

In our previous work, a population balance model describing the simultaneous processes of size reduction and mineral liberation has been developed. The experimental verification of this model, however, has been limited to a binary mineral system containing only one composite particle class. When considering multiple classes of composite particles, the estimation of model parameters becomes much more difficult. In the present work, a procedure for estimating model parameters for a multiple composite class model has been developed. Emphasis is placed on the direct experimental determination of these parameters. The physical significance of the breakage rate function and the liberation function in characterizing the liberation process is also discussed.

Jan 1, 1987

By L. L. Probert

A three-year project focusing on the depth profiling of respirable coal mine dust particles using scanning electron microscopy coupled with energy dispersive x-ray analysis resulted in the development of statistically classified particle-behavior models. The models depict the changing silicon fraction for 5-, 7-, 9-, and 11-keV accelerating voltages, thereby giving a clear indication of the nature of various types of particles. This paper will focus on the results for respirable quartz particles that occur in underground coal mines across the U.S. The relationship between the amount of surface-available quartz and coal seam rank is well established for Pennsylvania

Jan 1, 1994

By S. J. Zagula

Improved desulfurization of Illinois coals is a widely Shared research goal. The development of a physical cleaning strategy and the results of a project to demonstrate technical and economic feasibility of producing a low sulfur compliance coal from the Illinois Basin are reported. Processing flowsheets to extend or retrofit existing preparation plants are considered. Comminution, conventional and micro-bubble flotation, and selective agglomeration technologies were investigated to maximize pyrite rejection while maintaining high product yield. Batch bench scale testing was followed by continuous pilot plant studies. Parameters included grind size, flow rates, pulp density, aeration, agitation, and reagent dose. An economic evaluation of targeted processes is included.

Jan 1, 1987

By Jerry L. Fuller

Fan performance graphs are generated by digital computer using two programs, RUN- FANS and FANPLOT. RUNFANS calculates fan performance data from stored specific-volume, specific-speed data for a given fan type with appropriate allowances for fan diameter, rotational speed and air density. FANPLOT accepts specifications for drawing the graph and accepts either user-supplied pressure-quantity data or RUNFANS- calculated data as input, Operational procedures for both programs are detailed and examples of their interactive query routines are included. The hardware necessary to generate the graphs is illustrated. Several hardcopy output options are discussed,

Jan 1, 1984

By Arman Hazrathosseini, Ali Moradi Afrapoli

Fleet management systems (FMSs), as a pivotal part of any surface mining operation, need to evolve from conventional to intelligent systems because of both Mining 4.0 requirements and some shortcomings inherent in conventional methods. However, this novel transformation needs to be investigated technically and strategically. To this end, previously published research works on intelligent FMSs are explored to track the latest status of these third-generation frameworks within the surface mining context. Their underlying models are then compared in terms of five categories of allocation and dispatching features to pinpoint the technical gaps ignored. Having drawn the future lines of research, the present work then leverages the popular SWOT analysis method to outline the strengths, weaknesses, opportunities, and threats associated with the advent of these intelligent FMSs in mines of future. By and large, the analysis indicates that advantages outweigh disadvantages. Solutions are offered to address the existing weaknesses and threats.

Apr 1, 2024

By A. B. Cecala, G. W. Klinowski

Introduction The US Bureau of Mines has designed and evaluated total mill ventilation systems (TMVS) at two mineral-processing operations. Both systems have proven proficient at cost-effectively reducing respirable dust levels throughout the mills. An 11.8-m3/sec (25,000-cfm) system installed at a clay-processing mill provided about 10 air changes per hour (acph). This system reduced respirable dust concentrations by about 40% throughout the mill building. The second evaluation was performed at a silica sand operation. Tests were performed with 23.6 and 47.2 m3/sec (50,000 and 100,000 cfm) of ventilation to the mill building, corresponding to 17 and 34 acph. Average millwide respirable dust reductions were 36% and 64%, respectively. This work was done to determine general guidelines and design criteria for operations that may be interested in implementing TMVS. TMVS should be designed to draw clean make-up air in near the base of the mill. This air provides general purging and may clear some dust-laden areas throughout the mill structure. It is discharged at or near the top of the structure. Without the TMVS, dust can exit the building through open doors, windows, etc. and contaminate outside plant workers. This dust can also be recirculated back into the mill building causing additional contamination problems. TMVS is not a stand-alone system. It is a supplemental technique to assist other localized dust control systems (Mody et al., 1987). Testing Total mill ventilation systems were evaluated at two processing operations. For both tests, the primary goal was to determine the reduction in respirable dust throughout the structure. Test site No. 1. The first evaluation was performed at a clay-crushing and screening mill in New York. The mill's base dimensions were 39.6 x 9.8 m (130 x 32 ft), giving a volumetric capacity of 4250 m3 (150,000 cu ft). The TMVS was designed to provide 12 m3/sec (25,430 cfm) of ventilation air to the mill, representing about 10 acph. This was accomplished by three 4 m3/sec (8475 cfm) roof-powered exhaustors that were evenly spaced across the roof. Three wall louvers provided inlets for make-up air at the mill's base. Two evaluations were performed at this mill. The first occurred for two days in December when outside air temperatures ranged from -12.2° to 4.4° C (10° to 40° F). Temperatures with the wind chill factor dropped as low as -34° to -40° C (-29 to -40° F) during the early morning. The second evaluation was in April when outside air temperatures ranged between 10° to 26.7° C (50° to 80° F). These two evaluations verified the effectiveness of TMVS in lowering respirable-dust concentrations throughout the mill. Gravimetric-sampler respirable-dust concentrations in December ranged from 0.22 to 2.39 mg/m3 under normal conditions, compared to 0.13 to 1.55 mg/m3 with TMVS. In April, respirable dust concentrations ranged from 0.29 to 4.84 mg/m3 under normal conditions compared to 0.21 to 2.37 mg/m3 with the system on. TMVS also increased visibility throughout the mill building. Dust reductions for gravimetric and RAM-I instruments are listed in Table 1. Each value was determined by comparing the average concentration for the entire day of testing for normal and TMVS values. The mean/standard deviation values for gravimetric and RAM-1 results were 42.5/17.6 and 37.1/16.8, respectively.

Jan 1, 1996

By O. P. Sinha, Biswajit Mishra, A. K. Mandal, Raj Kumar Dishwar, G. S. Mahobia, Ram ji Omar

Most of the mineral deposits found in North-East India remain unexploited due to inadequate knowledge on their status, economic viability, and requisite mining technologies. The aimof this study is to characterize the multimetallic magnetite mineral deposit from the Nagaland area in India. The quality of iron ore was evaluated to establish its suitability as a raw material for iron production. Detailed studies were conducted to establish the composition and properties of the samples. X-ray diffraction (XRD), X-ray fluorescence (XRF), electron probe micro-analyzer (EPMA), and petrographic microscopy techniques were employed in the investigation. Shatter and tumbler test was performed for analyzing the mechanical properties of the ore. XRD studies indicated that magnetite is the major mineral with low amounts of martite, maghemite, and quartz. XRF/EPMA results indicated that magnetite contains 35–65 wt.% of iron and 1–5 wt.% of chromium. It also confirms the presence of Ni and Al up to 1 wt.% and Si up to 6 wt.%. Chromite-rich ore contains up to 30 wt.% Cr and 15–20 wt.% of Fe.

May 10, 2021

By B. A. Carbon

Western Australia is the largest state in Australia with an area one and three quarter times the size of Texas. Most of the State is desert or semi-desert, and only the southwest corner is heavily populated. The State has a population of one and a half million people, and one million of these live in and around the city of Perth. Perth is located on the narrow Swan Coastal Plain and is flanked by the Indian Ocean and the Darling Plateau. The Darling Plateau is an ancient peneplain rising some 300 metres above sea level, and forms an important resource base for the population.

Jan 1, 1984

By L. Alan Weakly

The Powder River Basin is the largest strippable reserve of compliant coal in the United States. It is the mother lode, for this Basin is currently supplying 25 percent of the coal produced in the US annually. This paper updates what has happened in the Basin since 1993 in terms of increased production, higher productivity, changes in mine ownership, safety statistics, new equipment, latest coal technologies, and electrical deregulation ramifications.

Jan 1, 1998

By C. Garcia, A. Potulska, J. J. Opazo, T. Comi

"The Sierra Gorda SCM sulfide ore processing plant began commissioning in the third quarter of 2014. Located in the Atacama Desert in northern Chile, the project is an open pit mine and Copper-Molybdenum processing plant is one of the most highly-instrumented operations in the world. It is the first hard rock operation in Chile and the second in South America to utilize HPGR technology. It is a significant Molybdenum resource especially in the first five years and the Molybdenum separation plant is complex. Designed to process up to 60 million lbs. of fine Molybdenum per year, it uses the latest technology and equipment to ensure superior recovery and product quality. It also has gas handling and alarm systems to fulfil the Company’s vision of “Zero Harm”. This paper discusses the overall operation and issues relating to the concentrator start-up. These include a review of the mineral processing design, the unified process control center and management information systems, and the correlation of geological and metallurgical performance data (mine-to-mill) for use in anticipating and preparing for treatment of diverse ore deliveries. INTRODUCTION Sierra Gorda SCM is a joint venture partnership with KGHM International (owned by KGHM SA, Poland), Sumitomo Metal Mining, and Sumitomo Corporation (Japan) operating in northern Chile. The Sierra Gorda open pit mine and Copper-Molybdenum processing plant will become one of the largest mines in the world. The need for optimum production efficiency and sustainability has driven the creation of the most modern, well-instrumented mine in Chile. This paper contains a general review of the project including geology and history. This was a very fast-track project going from greenfield site acquisition to mill start-up in 10 years. Highly-experienced and motivated engineers and technical staff have overcome many significant challenges resulting in a rapid ramp-up of production capacity. A potential expansion to double the production rate in the fourth year of operation has also been intensely studied. The Sierra Gorda property is located in the Atacama Desert of northern Chile, in the District of Sierra Gorda, Region II of Antofagasta, Chile (see Figure 1). There is almost no precipitation in this area. The mine site is generally flat with some rolling hills. The project is located about 5 km from the village of Sierra Gorda at an elevation of approximately 1,700 m above mean sea level. The village is near a highway and railway line. The city of Calama, home of the famous Chuquicamata Mine, is located about 60 km northeast of Sierra Gorda. In addition, the SG mine is in the midst of numerous other mines including Spence, Esperanza, Mantos Blancos, El Tesoro, Lomas Bayas, Gabriela Mistral, El Abra, Radomiro Tomic, and Escondida, to name a few."

Jan 1, 2015

Asgco’s design of the Arrowhead Ceramic Lagging provides solutions to problems experienced with conveyor belt slippage around the drive pulley and severe wear problems on snub and bend pulleys. Asgco has developed a range of pulley lagging from ceramic, drive rubber and non-drive rubber lagging that is available in abrasion-resistant SBR and MSHA grade rubber for conveyor pulleys from slow belts all the way through to high-speed, high load belts. There is a growing need for a maintenance-free and reliable pulley lagging to ensure conveyor belts run to their highest efficiency.

Jan 1, 2006

By Sahendra Ram, Priyadarshi Onam, Abhishek Kumar Singh

A numerical simulation study is carried out for assessment of stability of coal pillars having dirt bands by varying its size and depths. Physico-mechanical properties of dirt bands including thickness and its position in pillar system are varied in the simulation study. Results of the simulation study are correlated with the available empirical approaches of pillar strength are validated with field observations. It is observed that the presence of weak dirt bands significantly influences the strength of pillar. An attempt is made to develop correction factor for the available empirical approaches, which are developed without considering the weak dirt bands in pillar system. The findings of the study will be helpful for suitable design of different size of coal pillars at different depths and stages of depillaring operations.

Feb 1, 2025

By B. Pesic

This is an extension of the work on recovery of silver and manganese from Ag-Mn ores, and recovery of silver and gallium from flue dust from phosphate industry. Carbon adsorption was considered as the most adequate method for recovery of silver from thiourea leach solutions. For this reason it was decided to examine the characteristics of adsorption of silver on activated carbon. Coconut hard shell activated carbon was used for this study. Ag(TU)2C1 complex was dissolved into thiourea solution to give 2 gpl stock solution. Thy studied parameters were: loading isotherms at 25°C, 35°C, and 45°C, initial kinetics as a function of thiourea concentration, temperature, pH, N2, and O2. It was found that the loading capacity of carbon for silver and thiourea was 137-150 mg/g and 514 mg/g, respectively, at 25 °C.

Jan 1, 1986

By Robert D. Thomson

Land use is the single most important element affecting the quality of our physical environment. .The minerals industry is a user of land and by its very nature, directly affects the landscape. Mining is a very visible activity. Producers of sand and gravel, crushed stone, clay, cement and lime operate right at the interface of the public. These production sites must be located near population centers. People are more travel oriented than years ago and through use of the expanded interstate highway system visit remote and little-visited areas. They visit communities on their vacations, places they enjoy on weekends and places they drive past on business trips. Although not residents of these localities, they have a strong interest in changes that occur in the landscape. As a result, the public has a greater concern today about mining and its use of land. From 1930 through 1971, the minerals industry used 3.65 million acres, or 0.16 percent of the land mass in the United States (4)2/. Of the total 3.65 million acres utilized, about 59 percent was accounted for by the area of excavation, 20 percent by disposal of overburden and other mine wastes from surface mining, 13 percent by disposal of mill or processing wastes, and 5 percent by disposal of underground mine wastes; the remaining 3 percent was subsided or disturbed as a result of underground workings. Nonmetallic minerals and fossil fuels each accounted for 43 percent of surface land used during 1930-71; the metal mining industry utilized the remaining 14 percent.

Jan 1, 1976

By F. D. Ayhan

The aim of this study was to investigate desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by the agglomeration method. For this purpose, experimental studies were conducted on a mixture containing subbituminous coal, pyrite, quartz and calcite. The effects of some parameters that markedly influence the effectiveness of selective oil agglomeration, such as solid concentration, pH, bridging liquid type and concentration, and depressant type and amount, were investigated. Agglomeration results showed that the usage of various depressants (Na2SiO3, FeCI3, corn starch, wheat starch) in the agglomeration medium has a positive effect on the reduction of ash and total sulfur content of agglomerates. It was found that an agglomerate product containing 3.03% total sulfur and 25.01% ash with a total sulfur reduction of 56.71% was obtained from a feed that contained 7% total sulfur and 43.58% ash when FeCI3 was used in the agglomeration medium. Key words: Desulfurization, De-ashing, Agglomeration, Coal, Gangue minerals

Jan 1, 2009

By James E. McNulty

The planning and development of new coal mines is requiring the increased use of geologic, geologic engineering and hydrogeologic investigations. This is caused in part by the fact that new mines must deal with less favorable conditions than existing mines as well as higher costs of development and in part by the dictates of regulatory authority. High costs of new mines require greater reliability of geologic assessment using best available geotechnical and geophysical methods and technology. Although the increased cost of additional subsurface data is significant, the more important factor may be the impact on project lead time.

Jan 1, 1981

By M. Shriwas, F. Calizaya

"Recirculation is prohibited in many coal mining countries because of the fear that the re-use of return air would allow the build-up of air contaminants at the workings. The incorrect design and location of a booster fan in any ventilation network can create unsafe condition due to recirculation. The current approach to investigating recirculation using simulation software requires manual effort which becomes tedious in a complex and a large network. An algorithm-based C++ program was designed to detect the recirculation in a booster fan ventilation networks. This program needed an input file prepared from output file generated by any ventilation simulator. This program created an output file for recirculation. This program demonstrated the strong capability to detect the recirculation in a sample network and a coal mine ventilation network. The outcomes of this program were documented in this paper. INTRODUCTION The proper design and location of booster fans eliminate the safety hazards associated with high main fan pressure. Conversely, the incorrect design of booster fans in any ventilation network can create unsafe conditions due to uncontrolled recirculation. The proper utilization of a booster fan derives benefits to reduce the main fan pressure, leakage, and consequently ventilation cost especially with high resistance network due to deep and extensive working area in a mine. However installation of booster fan may create uncontrolled recirculation, if it is not sized and located properly with respect to main fan. Recirculation is prohibited in many coal mining countries because of the fear that the reuse of return air would allow the build-up of air contaminants at the workings. Therefore, it is imperative to check the recirculation while designing and operating booster fan for a ventilation network. This paper deals with an algorithm based C++ program to detect the recirculation in a booster fan ventilation networks. This program was implemented to detect the recirculation in a sample network and a coal mine network. STATEMENT OF PROBLEM The currently available ventilation simulation programs do not give much information about recirculation for the generated solution (fan pressures). The current approach to investigating recirculation using simulation software requires manual effort, i.e., traversing from node to node in the output network by the simulator while keeping tracks of all the nodes that form recirculation paths. This is an easy task in a simple ventilation network, but it becomes tedious and sometimes very confusing in a complex and large network. Moreover, the presence of multiple recirculation paths makes the manual effort more complex and difficult, especially in separating multiple loops that are connected together. Thus, there is a need for a more efficient program that will detect and quantify the recirculation efficiently, for the generated fan pressures. A program is developed to detect the recirculation(s) in a network."

Jan 1, 2015

By K. Häge

"Die Nachhaltigkeit der Braunkohlengewinnung in der öffentlichen Wahrnehmung wird nur weiter erfolgreich kommuniziert werden können, wenn durch konkretes Handeln glaubhaft gezeigt wird, dass die offenen Fragen fair und solide beantwortet werden. Dazu gehören insbesondere die neue innovative technische Lösung sowie das sensible Interessenmanagement. Die Braunkohlenindustrie hat gelernt, dass Offenheit und nicht zuletzt das beständige Bemühen um den Meinungsaustausch mit ihrem Umfeld wichtige Elemente sind. Der in Jahrzehnten erworbene Schatz an Glaubwürdig-keit ist eine Basis, auf der die Braunkohlenindustrie ihre Zukunft gestalten kann. Darüber hinaus sind politische Rahmenvorgaben erforderlich. Das öffentliche Interesse an einer sicheren und preiswerten Energieversorgung unter Einschluss der Braunkohle ist unverzichtbar. In diesem Kon-text kann dann die Braunkohle die an sie gerichteten Fragen der Ökonomie, der Ökologie und der Sozialverträglichkeit auch mit Hilfe von Indikatoren beantworten.ABSTRACTThe discussion of the sustainability of lignite mining can only be continued successfully if the indus-try acts in a practical manner and demonstrates trustworthiness by responding fairly and reliably to open questions. This includes new and innovative technical solutions as well as the sensitive management of interests. The lignite industry has learned that openness and the constant effort to exchange viewpoints within their environment are all essential elements. The credibility that has been gained over the decades is the foundation on which the lignite industry can build its future. Beyond that a framework of political guidelines is necessary. Public interest in a secure and inex-pensive energy supply that also includes lignite is indispensable. In this context, the lignite industry will then be able to answer the questions which are directed at them and concern the economy, ecology, and social tolerability also by indicators."

Jan 1, 2005

By B. A. Wills

With the increasing need to mine lower grade ores, high energy-related costs in comminution are of major concern. Very fine grinding is needed to liberate the very fine mineral particles in these ores. Not only is this expensive but it leads to greater losses in 'slimes'. In the early 1970's, 50% of the tin mined in Bolivia, 30% of the phosphate mined in Florida and 20% of the world's tungsten were lost in this way (Somasundaran, 1979). Gravity concentration techniques become unacceptably inefficient for particle treatment below 25-50µm, and even flotation fails in the ultra-fine range. Two approaches can be adopted to try to overcome this problem. The first involves increasing the efficiency of existing equipment or developing new slimes treatment processes. Gravity devices such as the Bartles-Mozley concentrator have been developed for this purpose and good recovery has been reported from 100µm down to 5µm. Such machines, however, have relatively low throughputs, so that large areas of plant space are generally required. Flotation is rapidly growing in importance for the treatment of ultra-fine minerals traditionally treated by gravity concentration.

Jan 1, 1986