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By M. E. Smith

Chile is the world's largest copper producer and as such sets the standard of practice in copper SX/EW design. The authors summarize the liner systems used at many of Chile's major copper producers both operating and planned. The evolution in the state of the art is also discussed, considering both economic factors and Chile's burgeoning environmentalism.

Jan 1, 1994

By T. Glenn Pobanz

For more than fifty years Walter Kidde & Company, Inc. has engaged in the development and manufacturing of both fire suppression and detection equipment. Our initial work for the mining industry centered around dry chemical extinguish-ing equipment for mine haulage cars. To fulfill this need, Kidde engineered and developed a manually activated dry chemical system to provide protection for the wheel wells, cable reels, and motor compartments on various pieces of underground mining equipment. The next phase of mining operation fire protection for Kidde was the area of detection and automatic fire suppression for conveyor belt heads. Early in 1970, a field evaluation program and belt head demonstration unit was taken to 10 areas throughout West Virginia, Kentucky, Pennsylvania, and Ohio. This extensive field program was a joint effort with National Mine Service Company of Pittsburgh, Pennsylvania. The objectives of this program were to study mine hazard problems and to determine further requirements of mine operators. The resulting belt head detection system centered around our Continuous Strip Thermistor Core heat detector in conjunction with a Kidde stored pressure dry chemical extinguishing system. Continuous Strip detection has been in use for a number of years in aerospace applications. It has proven flexible and reliable for the rapid detection of overheat conditions and fires in engines of over half the aircraft flying today. The use of Continuous Strip gave us flexibility to protect surface areas over and around the actual conveyor belt head equipment. The nature of Continuous Strip allows us to bend, wrap, and attach the 20 foot long thermistor element over the desired protected points of the belt head. An integral part of the conveyor belt head protection system is the control panel utilizing our comprehensive knowledge of fire alarm control logic. This panel contains supervision circuits which sound trouble signals upon detecting a break in the Continuous Strip; breaks in the wiring to the remote electrical extinguishing activators or to the alarm bell; or loss of primary power. A separate control module provides the adjustable alarm temperature setting of the

Jan 1, 1971

By Kefton H. Teague

Olivine was first described and named by Warner in 1790. It is an olive green to greenish gray colored magnesium-iron silicate containing a mixture, in solid solution, of fosterite (Mg2SiO4) and fayalite (Fe2SiO4). Ratios between fosterite and fayalite in olivine are somewhat variable, but in general olivine contains at least 85% fosterite. Specific gravity is variable also, depending on the ratios of fosterite to fayalite. As a rule it is in the 3.2 - 3.4 range. All commercial olivine is obtained from the rock dunite, the most basic member of the peridotite group. Dunites, in addition to being composed primarily of olivine, generally contain assessory pyroxenes and spinels (chromite and magnetite). Dunites', when altered by hydrothermal solutions or metamorphism, often contain alteration minerals such as talc, serpentine, chlorite, vermiculite and amphiboles. In the 1930's and 40's considerable research was conducted on olivine for use as a refractory, plant food raw material, magnesium source for metal, and a source for magnesium chemicals. This research met with only limited success.

Jan 1, 1977

By N. Damiano, J. Noll, C. Zhou, J. DuCarme

"Preventing machine-related injuries is one of the major safety concerns in underground coal mines. Severe injuries and fatalities occur when a miner is struck, crushed, or pinned by mining equipment such as a continuous mining machine (CMM), shuttle car, or a scoop. Proximity detection systems (PDSs) have been applied in mining to reduce these types of injuries and fatalities. All of the PDSs that are currently approved by the Mine Safety and Health Administration (MSHA) for use in underground coal mines are magnetic-field based and could be affected by metallic objects such as trailing cables. Researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated the influence of trailing cables on the performance of PDSs. In particular, the magnetic field coupled from proximity system generators to a de-energized trailing cable were characterized. The results show that significant energy can be coupled from the proximity system generators to a trailing cable when there is a closed loop in the cable. The effect on PDS performance from the magnetic field radiated around an energized trailing cable was also quantified for different current amplitudes in the cable. It is shown that the magnetic field caused by the electric current in the trailing cable mainly consists of a 60-Hz signal and its harmonics which cause little interference to the PDS. The results presented in this paper can help PDS manufacturers to design better systems that are more immune to these effects. INTRODUCTION An average of 250 injuries occur every year during operation of Continuous mining machines (CMMs), and 43 miners have been killed by striking or pinning accidents involving CMMs in the U.S. from 1984 to 2015 (Mine Safety and Health Administration, 2015). In addition, there have been 10 fatal accidents involving mobile haulage equipped with trailing cables from 2000 to 2015 (Noll et al., 2017). In response to these fatalities and injuries the Mine Safety and Health Administration (MSHA) promulgated a regulation in 2015 requiring the use of a proximity detection system (PDS) on all CMMs except full-face machines and proposed a regulation in 2016 which would require a PDS on other mobile underground equipment. Current PDSs approved for underground use are magnetic-field based. The PDS contains machine-mounted magnetic field generators that create fields around the machine. The other part of the PDS is a miner-wearable component (MWC) that reads the flux density of the generators. These systems use the magnetic field strength readings from the MWC to determine whether a miner is at a safe distance from the machine. A stable magnetic field is essential for the accuracy of the system."

Jan 1, 2018

By M. Kane, O&apos

BHP Iron Ore initiated research programs in January of 1995 to develop long term plans for decommissioning of the waste rock material at their Mt. Whaleback operation. More than 2 billion tonnes of waste rock were deposited during the past 30 years. Ultimately, the operators will deposit a total of approximately 5 billion tonnes in waste rock dumps constructed near the open pit. The Mt. Whaleback operation is located in a semi-arid climate adjacent to Newman, Western Australia, approximately 1200km north-northeast of Perth, Western Australia. The primary research program includes the development of technology for the long term performance of the waste rock dumps with respect to vegetation, slope stability, surface runoff, erosion, and water infiltration. This paper focuses on the design and implementation of a cover system to prevent water infiltration to the underlying waste rock. A laboratory program and the soil-atmosphere modelling completed to design the horizontal field test plots are described. The construction of the horizontal surface field test plots are discussed together with the field instruments installed to monitor performance. The key components of the instrumentation program are the design and installation of large scale field lysimeters to measure the unsaturated flow of moisture into the waste rock from the base of the cover layer. The cover system is designed to maximize infiltration during wet periods for subsequent evapo-transpiration while minimizing surface runoff. The result is a near zero net infiltration to the underlying waste material. A key feature of the design is the use of pit run waste material as the cover material. Monitoring is in progress and will continue for at least two annual wet/dry cycles. The optimum cover system should minimize the net infiltration of water to the underlying waste rock while maintaining physical and ecological integrity for long term performance.

Jan 1, 1998

By J. E. Golsan

Barrick Gold Corporation installed an expert style control system on the grinding circuit at its Mercur mine. Barrick's main objective was to increase mill throughput by a minimum of 3%. The expert system team collected operating data and then created a knowledge base using Comdale/X expert system development software. The expert system moved from on-line "advisory" mode, testing of expert rules, to full process control in four weeks. Expert system control benefits include a 9-15% increase in mill throughput, consistent mill loading leading to less wear on SAG mill parts, and improved downstream process control.

Jan 1, 1998

By C. R. Everly

"The purpose of this paper is to review the most effective methods of reducing chloride transfer and chloride removal in the solution extraction and electrowinning (SX/EW) process. Elevated chlorides in electrolyte have various negative effects including a reduction in current efficiency, increased handling costs at rod plants and smelters, increased anode corrosion, cobalt losses due to increased electrolyte bleed, degradation of HDPE piping, and increased corrosion in the SX/EW plants. Historical controls that Sierrita has used to control chloride transfer, in order of effectiveness, have been chloride gasification at the EW that is directly correlated to amperage and chloride concentration in electrolyte, wash stage bleed and efficiency, width and velocity of aqueous bands, and electrolyte bleeds. Maintaining high bleed rates and high amperage settings has been a challenge with decreasing pregnant leach solution (PLS) grades, so keeping chlorides out of the electrolyte has become imperative. The effectiveness of reducing aqueous entrainment, optimizing wash stage efficiencies, and improving organic quality to reduce the transfer of chlorides to the electrolyte are illustrated in this study. INTRODUCTION The transfer of impurities from PLS feed streams to electrolyte in the Copper Solution Extraction process is a very common problem and is the reason that the wash stage exists in most SX operations. The main impurities affecting the SX process are iron, chloride, nitrate, and manganese. Elevated chlorides in the electrolyte have various negative effects including reduced current efficiency, increased handling costs at rod plants and smelters, increased anode corrosion, increased cobalt losses due to increased electrolyte bleed, degradation of HDPE piping, and increased corrosion in the SX/EW plants. Freeport-McMoRan Sierrita Hydromet is unique in that a high-chloride byproduct stream from the molybdenum process is pumped into the SX raffinate solution pond. This byproduct steam accounts for the majority of chloride introduced to the circuit, and over the years has built up to a point where 4000ppm chloride is consistently in the PLS feed to the SX. Concentrations of chloride over 70 ppm in electrolyte will result in downgraded cathode, so it is important to limit chloride carryover from SX as much as possible. Historically, Sierrita has been able to manage chloride levels with reactive techniques including increasing electrolyte bleeds and rectifier amps. Decreasing copper in PLS has made high amps harder to maintain, and increasing bleed rates have a direct impact on production goals."

Jan 1, 2015

By A. D. Pernichele

Four types of slope failures in waste dumps are recognized; debris flow, foundation failure, edge slump and blowout. The first three types, although at times causing considerable damage to property and interfering with mine operations, are not usually dangerous to personnel because of their slow rate of movement. The fourth type, the blowout, is considered to be the most dangerous because of its explosive mode of failure and lack of forewarning. The December failure at Verona dump is presented as an example of a blowout. Data from piezometer holes indicate that the blowout was due to perched leach solutions near the face of the dump. The level of water in this zone is very closely related to the rate of leach water application on the dump. A detailed analysis of core samples indicated that the impounded water was due to a zonal accumulation of Jarosite which is associated with a buried dump surface. Drain holes proved successful in controlling perched leach solutions in the critical zone near the face of the dump. Monitoring of the water level in the perched zone is considered essential in preventing blowouts. The use of drain and piezometer holes has allowed an increase in the rate of water application on the dump while preventing additional failure.

Jan 1, 1971

By N. K. Dumakor-Dupey, K. J. Bansah

"We made site visits to determine potential environmental issues caused by artisanal and small-scale mining (ASM) in the Tarkwa Mining Area (TMA) of Ghana. Activities of the diggers were observed to degrade vegetation, land and water. Improper handling of mercury was also identified as a major threat to people and ecosystem. Large abandoned pits and trenches posed fall traps to farmers, hunters and wildlife. We argue that lack of adequate monitoring and regulatory enforcement by Ghanaian authorities, together with inappropriate mining processes, probably due to lack of technical expertise are contributing factors to the environmental issues of artisanal and small-scale mining in the TMA. INTRODUCTION Environmental degradation caused by artisanal and small-scale mining (ASM) has been a major concern to many people and governments around the world. ASM is often associated with health, safety and environmental issues in communities where it is practiced (Kitula, 2006; Asiedu, 2013; Sousa et al., 2010). Some of the environmental issues that have been reported include land degradation, mercury contamination, cyanide release, and pollution of rivers/streams. These issues have been attributed to improper mining methods, inefficient technology, lack of technical training and environmental awareness, and lack of regulatory enforcement (Serfor-Armah et al., 2005; Bansah et al., 2016a; Hentschel et al., 2002). In Ghana, ASM typically occurs in rural communities, providing jobs to many people and contributing towards socioeconomic growth of the country (Banchirigah & Hilson, 2010; Bansah et al., 2016b; Osei-Kojo & Andrews, 2016). As a result of the environmental issues, many people have called on government to develop drastic measures to control ASM operations. It is in this regard that this paper examines potential environmental issues caused by ASM in the Tarkwa Mining Area in Ghana, and suggests mitigation measures to ensure environmental sustainability. ASM in the area comprises of registered (licensed) and unregistered (unlicensed) operations that adopt surface or underground mining methods to exploit gold-bearing materials. Surface operations typically involve clearing of vegetation, removal of overburden, excavation of mineral deposit, washing/grinding of excavated gravels and processing with mercury. Except grinding, washing and mercury recovery, underground operations are conducted below ground with limited impact on the surface. Alluvial mining is also commonly practiced in streams and along river banks. These activities can have devastating impact on biodiversity of the ecosystem. To achieve the objective for this study, field visits were made to ASM sites to observe operations and interact with diggers. Visits were also made to host communities of ASM and government officials to obtain their perspectives on ASM in relation to environmental impact. The study area (Tarkwa Mining Area) is located in the Western Region of Ghana (see Figure 1). It is endowed with natural resources such as gold and manganese. Hence, mining is the major economic activity in the area. ASM is widespread, with 15 registered operations and several unregistered mines. The environmental issues observed in the study have been grouped into three main categories: vegetation and land depletion; water quality and pollution issues; and mercury contamination issues."

Jan 1, 2017

By J. T. Ryan, Griffin. Wayne H.

This paper shows that if a drift has a brattice which is sufficiently leaky, changes in the operating point of the fan depend solely on the volumetric efficiency within the drift. Under this high leakage condition, an increase in the length of the drift causes very little shift in the fan operating point. For less leaky brattices, the operating point depends on both the fan characteristic curve and the volumetric efficiency. It is shown that for the fan curve and drift parameters used in this paper the fan operating point in a drift with a volumetric efficiency of 50% is essentially the same as a drift which has a zero efficiency. In this region of efficiency, an increase of 300% in the length of the drift causes only a 3% increase in fan operating pressure.

Jan 1, 1993

By M. J. Hrebar

This paper reviews large dozer stripping techniques and presents results of two field studies. The first is a seven-shift study of a contour block stripping operation where a Caterpillar DII is used as the primary stripping equipment. The second is a two-shift study of two Cat DIIs dozing blast cast material ahead of a dragline operation. Surveys and continuous time studies were used to determine production rates and as a basis for forecasting unit stripping costs in both cases.

Jan 1, 1994

By W. Z. “Ben” Wu

The investigation provides a method of efficiency evaluation among several kinds of tools employed to cut different types of rocks. A ballistic test stand incorporated with a modified Hopkinson bar was used to simulate a percussive drilling tool. An Apple IIe microcomputer was employed for high speed data acquisition and numerical analysis. A newly developed method for remote monitoring the rock-tool interaction, including contact force, bit penetration and energy transmission,is presented in the paper. Theoretical predictions and experimental results appear in faily good agreement

Jan 1, 1986

By K. W. Deter

The gold ores in the Jerritt Canyon district have been recognized as refractory since they were first encountered by FMC geologists in 1976. Upon obtaining managing rights as joint venture partner, Freeport McMoRan Inc. developed an operating plan featuring carbon-in-leach gold recovery techniques for the oxide portion of the ores and a patented sulphide oxidation step followed by chlorination for treating the organic carbon constituents of the refractory ores prior to CIL gold recovery. The plant was successfully started up in 1981 with the first gold poured on July 4, 1981. Initial plant throughput was designed to be 2495 MTPD (2750 STPD) total through the dual processing trains.

Jan 1, 1991

By Richard Minnitt, Philippe Renard, Christina Dohm, Winfred Assibey-Bonsu, Matthew Aboagye, Julien Straubhaar, Mahlomola I. Mabala

The application of multiple point statistics (MPS) in oil studies has gained traction over the years; however, the use of MPS in mineral resource estimation and classification is still limited. This is despite MPS’ ability to deal with complex and heterogeneous geology better than the commonly applied two-point based methods. The availability and choice of a representative training image (TI) are often cited as the main challenge holding back MPS’ application in mining geostatistical studies. On the other hand, the general approach used in mining whereby early focus is on higher grade areas and lower grades are planned to be mined later presents a massive opportunity for the development of representative TIs. Mined-out areas provide large amounts of historical data that can be used to develop training images or training datasets that can be used to estimate in mining extension areas (often lower in grade), provided low grade areas are underpinned by similar geology analogue. This approach will enable more robust estimates in mine/pit extension areas for both high- and low-grade extensions than with traditional two-point geostatistical methods.

Jun 25, 2023

By W. M. Schafer

The risk that water quality will be degraded by mining activity can be evaluated using risk analysis techniques. Water quality impacts can occur where water-rock interactions with tailings, waste rock, or leached ore lead to increased loading of constituents into surface or groundwater. Constituent loads contributed by mining facilities are determined by the migration route and chemical evolution of mine water. Mass load contributions from mines can be determined by estimating the prototype pore water in contact with mining waste, predicting the rate and timing of flow, assessing the degree of geochemical attenuation, and modeling chemical mixing with natural surface or groundwater. Mining facility siting and design measures can alter the chemical evolution of mine water by varying the quantity or quality of flow. Stochastic risk management techniques provide a powerful tool for quantitatively identifying the environmental consequences of various siting and design alternatives.

Jan 1, 1998

By Steve Richards

Incorporating a bottleneck analysis into the mine plan can provide a significantly better basis to make economic decisions regarding materials handling systems. Every materials handling system has a bottleneck. The bottleneck at a mine may change over time as a function of location or time. Since a mining reserve is a finite amount and can usually only be mined once, knowing how the bottleneck changes can provide a critical backdrop to capital investment decisions, especially those affecting the materials handling system. A bottleneck analysis can better quantify the expected 'return and also indicate the optimal time to complete tile project.

Jan 1, 2002

By M. Hancer

The sign of the surface charge of selected potassium soluble salt minerals namely KClO4 , K2SO4 , KNO3, and KCl was determined from nonequilibrium electrophoresis measurements and found to be negative for each of the salt. Dodecylamine flotation of these salts revealed that the concentration of amine required for flotation increases in the order KClO4< K2SO4< KNO3<KCI. Precipitation of the amine collector colloid was not required for flotation of the oxyanion salts and in this case it appears that adsorption of the dodecylamine cation is sufficient to create the hydrophobic surface state. The order for flotation is explained in terms of surface hydration of these respective potassium salts based on contact angle measurements and FT Raman spectroscopic characterization of water structure.

Jan 1, 1999

By J. R. Sturgul

A dynamic input-output model for a coal power enterprise that now includes four underground coal mines, three coal washing plants, a power plant and a railway transportation system was developed. The model is applied to analyze investment alternatives for long-term development, including the expansion of existing mines, the opening of new mines, the construction of new coal washing and power plants and the upgrading of the railway system. As a result, the optimal investment strategy with capital schedules and projected sector outputs is obtained. Also, the importance of the new power plant to the strategic development of the company is demonstrated. It is concluded that, without applying a dynamic input-output model, it would be much more difficult or impossible to conduct such a systematic and compete analysis.

Jan 1, 1999

By P. K. Davis, B. Gharib

The results of a previous basic study of the flow and design characteristics of hydrocyclones demonstrated that a recovery as high as 99% with a product rating* of 0.95 can be achieved on a batch+ basis with a single, water-only cyclone if it is configured properly. The next logical step was to demonstrate continuous processing of gob for the efficient recovery of coal by means of a laboratory-size demonstration system. A project to design and construct such a single-¬cyclone system was sponsored by the US Department of Energy, which also sponsored the initial study. A recovery of 93% with a product rating of 0.89 was demonstrated. The system design and the data taken are discussed.

Jan 1, 1990

By Felicia F. Peng, Victor Z. Sun, Syd S. Peng

A probability-based analysis method in conjunction with the finite element structure modeling technique to evaluate an entry system stability is developed. Variability of the rock properties and loading surrounding the entry system is taken into consideration to predict a roof stability by using the probability of failure instead of the common safety factor concept. A dynamic programming is applied to establish a recurrence relationship between the degree of potential roof fall and accumulated roof fall index in an area of interested. A probable distribution of roof fall is assessed by using a developed computer program, RFSTAB. The assessment of the roof falling boundary in the longwall entry system is used as the example to illustrate the procedure and effectiveness of this analysis method

Jan 1, 1996