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By C. H. Bucknam

Metallurgical processing of gold ores in positive water balance environments has been facing decreasing discharge concentrations in permits and additional requirements to pass acute toxicity testing before discharges will be allowed to native fisheries. In response to the challenge to meet 0.005 mg/L free cyanide guidance for discharges to fresh water fisheries, the American Society of Testing and Materials (ASTM) International Cyanide Task Group has undertaken an interlaboratory study for the free cyanide method in the metallurgical processing cyanide detoxified reverse osmosis effluent to determine if the quantitation limit for the method could be lowered from the current 0.009 mg/L free cyanide (1) to less than the 0.005 mg/L guidance concentration. Results of the testing are presented below.

Jan 1, 2012

By D. E. Walsh

With the exception of the development of large scale mining equipment (haul trucks, draglines, shovels, etc.), there are likely few other candidates responsible for the ability to exploit large tonnage, low grade deposits, than the development of large capacity comminution equipment and circuits; crushers and grinding mills. Ball mills are often the final step in the comminution process and are responsible for providing what should be the optimum particle size distribution of ore to subsequent mineral concentration steps in the flowsheet. Because comminution processes are such high cost centers for milling operations, both capital and operating costs, an enormous amount of research has been conducted to study and model their performance, in order to improve efficiencies (Kelsall, et al., 1969; Austin et al., 1984; Napier-Munn, et al., 1999; Powell and Smit, 2001). With respect to modeling ball mills, estimates of the breakage rates for individual size classes of ore particles are fundamental, as are the particle size class breakage functions (the progeny of particle sizes produced from breaking a coarser particle size class), also termed appearance functions. Fundamental research into particle breakage in tumbling mills focuses on how much energy is input into single particles versus how they break and what size distribution of particles results. Several test methods, including JKMRC?s well known dual pendulum test and drop weight test, have been developed for the breakage of coarse particles down to 6 mm in size (Napier-Munn, et al., 1999). Work on the breakage of finer particles is still an area of intense research and single particle breakage is being investigated as are multiple particle, fixed bed methods (Hoffler and Herbst, 1990; Bourgeois et al., 1992; Whiten, 2007).

Jan 1, 2011

By G. L. Simmons

Aqueous pressure oxidation at low temperature, although desirable from a process engineering and operations point of view, presents unique problems when temperatures approach 160°C (320°F). In developing the pressure oxidation process for the Lone Tree Mine, elemental sulfur formation and agglomeration with pyrite proved to be a problem. This paper discusses some of the unique features of the Lone Tree sulfide deposit and its amenability to low temperature oxidation. Problems encountered during pilot plant operation and their solutions are discussed.

Jan 1, 1993

Aqueous pressure oxidation at low temperature, although desirable from a process engineering and operating point of view, presents unique problems when temperatures approach 160°C (320°F). In developing the pressure oxidation process for the Lone Tree Mine, elemental sulfur formation and agglomeration with pyrite proved to be a problem. This paper discusses some of the unique features of the Lone Tree sulfide deposit and its amenability to low-temperature oxidation. Problems encountered during pilot plant operation and their solutions are discussed.

Jan 1, 1995

By S. N. Gurulaxmi, Veerendra Singh

The abstract discusses the increasing consumption of manganese ores and the need to utilize low-grade ores and rejects. The study focuses on developing a low-cost process using a cupola furnace to recover manganese values from these resources. The process involves smelting ore blends to produce high MnO slag and pig iron. The study investigates various factors to improve iron reduction and separation from MnO-bearing slag. The results show that the process can produce slag with MnO > 35% and Fe(t) < 5% using low-grade Mn ores. The process also achieves Fe reduction between 50 and 70%. The cupola furnace offers advantages like low cost and ease of operation, making it suitable for processing low-grade ores and rejects to produce synthetic MnO-enriched products for various industries.

Apr 1, 2022

By T. McWaters

Miami Copper Company began a block-caving operation in 1911 using a gravity mill to separate copper minerals from the Pinal Schist host rock. The tailing was deposited by the upstream method using perimeter launders and spigot valves in six canyons adjacent to the mill until 1932. In 1928 the larger and more distant Solitude tailing pile was developed which by 1932 was receiving all tailing except for upsets. In 1925 Miami Copper converted its gravity mill to flotation which began to produce higher sulfide copper recoveries.

Jan 1, 1990

By Gábor Antal, József Bõhm, Barnabás Csõke

From the waste material of the production of aluminium foil aluminium pigment is produced for the paint industry by grinding it in white spirit. During grinding 1-2 % iron impurity gets into the product, weakening its quality, from the wear of the mill armour and the grinding bodies and from the contamination of the raw material. For deironing the product, a stage-operated electrically induced magnetic filter separator was developed and put into operation. The separator was sited in an explosive environment and therefore required a special design and safety system. The paper describes the results of the development work. the device that was developed, the safety system as well as the results of and experiences with the operation of the separator.

Jan 1, 1995

By S. Komar Kawatra, Henry J. Walqui, Timothy C. Eisele

Population balance models were used to model the grinding action of industrial scale coal pulverizers. Experimental work was conducted with two different coal samples to determine the values of the appearance and selection function. These functions were determined for vertical mills by using s 6-inch by 10-inch laboratory roll mill to represent the action of a vertical mill. Two very important operating variables were identified for vertical mills: feed rate and roll spacing. Factorially designed experiments were used to analyze .and quantify the effect of these two variables. The models were then adapted to represent changes in operating conditions by incorporating the effect of the feed rate and roll spacing effects. This resulted in a simulation model able to respond to changes in operating conditions, by providing corrected predicted values for the product size distribution.

Jan 1, 2002

By H. Mischo, F. Daniela, L. Schaarschmidt, I. Paschke

In order to safely store radioactive waste long-term, HAW repositories in saliferous formations have to be backfilled. The main purpose of those backfill operations is the restoration of the geological barrier function of the containment area. For best possible results the used material should be of a comparable composition or characteristic for the host rock formation. Additionally, the material should show a high density after completion of the backfilling process as well as a low permeability. A major aspect to consider in these processes is the minimization of the gap of the backfill body to the roof of the drift. To fulfil those requirements, a micro-structure stabilized crushed salt backfill material has been developed as part of the GESAV-I-project. Due to the material composition of this so-called GESAV-material, salt mineralcrystallization processes start after emplacing it, a process that leads to the polyhalite formation. With the crystallization of polyhalit, the halite grains are bridged, which in return stabilizes the matrix of the backfill. The GESAV-II-project continued successfully what GESAV-I started and determined an ideal backfill method in order to build the backfill bodies composed of GESAV-material. Due to the compaction of the material during emplacement by vibration, high in-situ densities, low permeabilities and a backfill factor close to 1 was able to be reached. In the following SAVER project this journey of practical test underground will be continued.

Mar 2, 2022

By Ian Sherrell, Christian Cardoso, Henri Vepsäläinen, Guillermo Bermudez

Performance of mixing mechanisms in flotation cells is paramount, as inefficiencies can lead to financial losses through valuable minerals lost to tailings. Technological advancements have been implemented in flotation cells to optimize performance, but regardless of the efficacy of these developments, room for improvement may persist. Since its launch in 2005, FloatForce® has set a high industry standard for flotation mixing mechanisms. However, current mining trends call for sustainability-driven developments while improving metallurgical performance. Metso has recently introduced FloatForce®+, the latest iteration of FloatForce, developed through extensive laboratory, pilot, and industrial testing, aligning with mining sustainability trends. It has been designed to maximize recovery, reduce power draw and optimize manufacturing materials. This development stems from a redesigned rotor profile paired with a harmonizing stator configuration. This paper presents the development journey of Metso’s latest patented flotation mixing mechanism, an advancement to improve metallurgical performance at a high sustainable standard in flotation cells. The theory, CFD modeling and test work are discussed in detail.

Feb 1, 2025

By S. Pastor, S. Hahn

"As the concept of autonomous haulage systems (AHS) moves from proto-types to production-ready applications, the operating performance of the haul road will become ‘mission critical’ to the overall success of autonomy in mining. Deterioration in road performance will require remediation, human intervention and significant, albeit temporary, changes to operating procedures, to accommodate road maintenance. With autonomous trucks comes the opportunity to reduce road formation and operating width, and therefore generating potentially significantly reductions in stripping ratios and improvements to mine economics, but only if the design of the road, and it’s associated deterioration rate, is predictable and manageable, based both on the materials used to construct the road and the maintenance interventions to be carried out on the road. This paper presents the assessment of a digital photogrammetric approach to the characterization of a mine haul road surfacing, or wearing course material. Design and maintenance parameters for these roads are currently determined from physical particle size distribution (PSD) assessments of ‘in-road’ material. However, this approach does not accommodate the need, nor leverage the benefits from, AHS. The digital imaging approach is assessed in this paper, using two standard digital analysis software tools, together with in-service mine haul road wearing course samples and images which are assessed to determine the applicability and reliability of the approach to deliver a real-time assessment of haul road surfacing conditions and thus to identify the road maintenance interventions required to address deterioration. INTRODUCTION Enhancements in mine road design, construction and management for the past 20 or more years has largely been focused on short-term tactical needs. These improvements have not been matched by advances in the fundamental technologies that underpin mine road design and management, and although the quality of mine roads have probably increased, many of fundamental and longer-term issues have yet to be addressed. With AHS’s evolving from prototype to production applications, any decision to implement these systems in a mine requires a thorough evaluation of impacts, not only operational improvements, but the inter-connectivity of this autonomy technology to other organizational processes. In developing an understanding, the full interactions that may affect autonomous truck behaviour due to changes in various sub-systems or external environments, haul road conditions and operating performance is a key consideration. This is as true in autonomous as well as in conventional mine truck-based hauling systems where the mine haul road network is a critical and vital component of the production process."

Jan 1, 2015

By S. Pastor, S. Hahn

"As the concept of autonomous haulage systems (AHS) moves from prototypes to production-ready applications, the operating performance of the haul road will become critical to the overall success of autonomy in mining. Deterioration in road performance will require remediation, human intervention and significant, albeit temporary, changes to operating procedures, to accommodate road maintenance. With autonomous trucks comes the opportunity to reduce road formation and operating width. This will, therefore, generate potentially significant reductions in stripping ratios and improvements to mine economics, but only if the design of the road, and its associated deterioration rate, is predictable and manageable, based on the materials used to construct the road and the maintenance interventions to be carried out on the road.This article presents the assessment of a digital photogrammetric approach to the characterization of a mine haul road surfacing, or wearing course material. Design and maintenance parameters for these roads are currently determined partly from physical particle size distribution (PSD) assessments of ‘in-road’ material. However, this approach does not accommodate the need, nor leverage the benefits from, AHS. The digital imaging approach is assessed in this article, using two standard digital analysis software tools, together with in-service mine haul road wearing course samples and images that are analyzed to determine the applicability and reliability of the approach to deliver a real-time assessment of haul road surfacing conditions and thus to identify the road maintenance interventions required to address deterioration.Enhancements in mine road design, construction and management for the past 20 or more years has largely been focused on short-term tactical needs. These improvements have not been matched by advances in the fundamental technologies that underpin mine road design and management and, although the quality of mine roads have probably"

Jan 1, 2015

By D. Shink

A small scale continuous flotation cell was designed and constructed at Noranda Technology Centre to develop a mobile testing flotation circuit located next to the production circuit. This mobile small scale flotation pilot plant can easily and economically be set up at any circuit in a mill and used to evaluate and predict plant performance against a given flotation condition. The main feature of the cell, beside the provisions of automatic pulp level and feed rate control, is to provide a reduced surface to volume ratio approaching to that of an industrial machine. This paper describes the basic design and the results of various testwork carried out to date including aeration, conditioning, reagents, recirculation, flotation gas, etc. are presented in comparison with the plant production results.

Jan 1, 1992

By C. A. Moseley, M. B. Kahle

The Gulf Coast Region has been the center of extensive lignite exploration and development activity in the past 10 years. Currently, 27.2 Mt (30 million st) of lignite are mined annually, the majority of which is uncovered by large walking draglines. Projections indicate that production could reach 125 Mt (138 million st) by 1990. As mining moves to deeper depths, removal of overburden becomes the decisive factor in mine planning and cost. The geology of a region plays a key role in the selection of an overburden removal system. While alternate stripping methods must be analyzed to determine the most economical and operationally sound method, so far bucketwheel excavator systems seem to be the best method for removing large volumes of soft, unconsolidated material that is found at projected mining depths in the Gulf Coast region. Geology of Gulf Coast Lignites Extent Distribution of the principal tertiary lignite-bearing deposits in the Gulf Coast Lignite province extend from the Texas-Mexico border to the Alabama-Georgia state line (Fig. 1). The lignite-bearing strata includes portions of eight states: Texas, Louisiana, Arkansas, Missouri, Kentucky, Tennessee, Mississippi, and Alabama. Lignites occur primarily in the Wilcox, Claiborne, and Jackson groups in the Gulf Coast. The uppermost strata of the Midway group in Mississippi and Alabama also contain significant lignite resources. Reserves Commercial lignite seams in the Gulf Coast Lignite province range from 0.6-3 m (2-10 ft) in thickness. The estimated lignite resources throughout the Gulf Coast in seams greater than 0.9 m (3 ft) in thickness and up to 61 m (200 ft) in depth currently are estimated at 32 Gt (35 billion st). Table 1 shows these resources by state. Quality Lignite quality can vary within individual mining areas and seams. However, trends in quality occur because of the depositional environment, age, and west-to-east geographical location. Better quality lignites occur in the Wilcox group in Texas and Louisiana. Poorer quality lignites occur in the northern regions of the Wilcox group and those of the geologically younger Claiborne and Jackson groups. Environmental Conditions Gulf Coast province environmental conditions are ideal for successful mine reclamation. The lignite occurs in flat to moderately rolling terrain, a topography easily reproduced from the spoil dumps or spoil rows developed during the mining operation. High to moderate rainfall facilitates rapid revegetation. Evidence from current mine reclamation programs and ongoing test plot studies indicate that mined lands can be reclaimed to reach premining productivities. Sometimes productivities are even greater than that of premining conditions. Existing Mining Methods Present Mines & Production There are seven active mines in the Gulf Coast province, all located in Texas (Fig. 2). Lignite

Jan 8, 1983

By Rainer Kahrger, Guenter Ewald

The topic of this paper is to demonstrate the development of mobile crushing installations from throughput capacities of 200 tons per hour, to mobile and semi-mobile large- scale crushing installations with throughput capacities of 3,500 up to 10,000 tons per hour. Basis are approximately 140 mobile and semi-mobile crushing installations which have been built since 1956 or were on order in 1987. [FIGURE 1. Total Number of Mobile or Semi-mobile Crushing Plants] Sixteen of these approximate 140 mobile and semi-mobile crushing installations have a throughput higher than 3,500 metric tons per hour. Mobile crushers were developed more than 25 years ago in Europe for the quarry industry, which had special requirements - fairly low capacity, mostly softer and less abrasive material (limestone) and full mobility. So the majority of the units up to about 1980 were fully mobile, having a fairly small capacity and utilizing mainly hammermills, double roll and impact crushers. It was only when the mining industry and large quarries picked up the concept in the early 1980&apos;s that a drastic increase in capacity took place. Even though the first mobile crusher in a true mining application went into service in 1971, it took another 10 years before it proceeded in a larger scale. This trend was obviously supported by the drastic fuel price and energy cost increase in the mid 70&apos;s. Since the cost of conveying material is substantially cheaper than trucking it, the increase in energy cost, combined with increasing haulage distances provided a strong incentive. Figure 1 shows clearly the throughput distribution of all crushing installations and it also shows the sharp increase in the throughput capacities within the last few years.

Jan 1, 1989

By Michael S. Zhdanov

One of the major problems of mineral exploration is the ability to reliably distinguish between uneconomic mineral deposits and economic mineralization. While the mining industry uses many geophysical methods to locate the mineral deposits, until recently, there was no reliable technology for mineral resources identification and characterization. The main goal of this project is to develop a new geophysical technique for subsurface material characterization, mineral exploration and mineral discrimination, based on electromagnetic methods. The proposed new technique is based on examining the spectral induced polarization effects in electromagnetic data using the modern distributed acquisition systems and advanced methods of 3-D modeling and inversion. The recovered parameters of the relaxation model will be used for the discrimination of different rocks, and in this way will provide an ability to distinguish between uneconomic mineral deposits and zones of economic mineralization using geophysical remote sensing technology (Zonge, 1976). The proposed research and development is undertaken using multi-partner collaboration between the University of Utah, four major mining companies, Kennecott Exploration, BHP Billiton World Exploration Inc., Placer Dome Inc., Phelps Dodge Exploration, and Zonge Engineering Inc., which is equipment manufacturer and service provider to the mining industry. The multi-partner collaboration between the academic institution, the University of Utah, and mining industry helps to identify the appropriate mining target and conduct the field experiment for practical demonstration of the developed new technology, which is an important part of the this project.

Jan 1, 2005

By G. M. Rao, P. N. Deo

Graphite is soft and easily floatable but it is quite difficult to obtain high purity concentrate at coarse sizes. Chemical treatment can produce high grade concentrate but it is an expensive process. Graphite containing plus 96% fixed carbon (FC) with coarse flakes commands high price in international market. Such graphite concentrate containing plus 96% FC was produced in Indian Bureau of Mines (IBM) by using newly developed reagent (mixture of different hydrocarbons and terpenes, IBM/D7) instead of commonly used frothers viz. pine oil, MIBC, kerosine etc. and regrinding in a special type of mill with special grinding media instead of grinding in a conventional ball/ rod mill followed by cleaning. Both the new reagent (frother) and special grinding media are inexpensive and readily available. The process is under patenting. This paper focuses application of this new grinding methodology for flake size protection, and the new reagent for selective flotation of high purity graphite.

Jan 1, 1995

By Yoshinori Shimada, Oleg Kotiaev, Hiroaki Sakamoto, Toshihiro Asakura, Naotoshi Yasuda, Norikazu Misaki, Masahiro Shinoda

"To ensure that trains run safely, the performance of railway civil engineering structures is checked by periodic inspections. General inspection method has merits and demerits, but none of them offers the combination of high accuracy and quick inspection. In an effort to resolve this problem, West Japan Railway Company, the Institute for Laser Technology and the Railway Technical Research Institute jointly developed a remote laser sensing system as an alternative to the impact acoustics method for detecting defective concrete elements in tunnel linings. The proposed remote laser sensing system has two lasers, one to apply an impact to the concrete surface and the other to measure the vibration of the concrete generated by the impact laser. The impact laser is a high-energy pulse laser that induces vibration in the concrete. The detection laser has a signal beam and a reference beam. The signal beam reflects on the concrete surface and goes into the dynamic hologram crystal. The reference beam diffracts in the dynamic hologram and enters the detection sensor with the signal beam. The vibration of the concrete surface can be measured to detect the movement of an interference pattern. A prototype of the remote laser sensing system was developed as shown in Figure1. A vibration and acoustic insulators are equipped to remove a noise generated from a maintenance car or electric generator in this system. The proposed laser remote sensing system and the detection algorithm were verified with the help of field test conducted in a tunnel on the Shinkansen. An impact test using hammering was applied to obtain the accurate response acceleration on the surface of the concrete before application of the proposed method. In this test, the result obtained from the proposed method has good agreement with that obtained from the impact test by hammering. Consequently, it is verified that the proposed method can be used as an alternative to the standard impact acoustics method."

Jan 1, 2016

By J. Derwin King, Harrison R. Cooper

Applications of nuclear magnetic resonance (NMR) offer possibilities for on-line sensing of the concentrations of several elements in flowing sample streams. In addition to hydrogen, these elements, generally of low-order atomic number, include aluminum, phosphorus, fluorine, sodium, boron, and lithium contained in minerals having commercial importance. Many such elements have been difficult or impossible to successfully measure on-line using the more familiar X-ray fluorescence and neutron activation analysis techniques. The availability of practical on-stream analysis methods is essential to applying advanced controls to processes incorporating these elements. On-stream NMR instrumentation has been demonstrated in the past for several process applications including, as an example, coal flow and analysis; and the technology has recently been extended to the measurement of phosphorous BPL in Florida beneficiation plants. The technique involves simultaneous sensing of proton (hydrogen) and 31P intensities to provide data for continuous calculation of BPL in the phosphate through calibration to volume fractions of water and solids. Initial operating results are described using the PhospholyzerTM on-stream phosphorous analyzer designed for plant application.

Jan 1, 1990

Micro-computers have made it practical to install a high-speed acquisition system to collect data from a longwall face in near real-time. By simultaneous data analyses using neural networks and fuzzy sets, information regarding longwall mining performance and underground behavior can be provided and forecasting longwall instability and detecting geological anomalies is feasible. This paper presents details of the application of neural networks and fuzzy sets in developing on-line evaluation of longwall roof behavior. Techniques for interpreting longwall shield pressures and characterizing roof conditions are discussed.

Jan 1, 1996