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By R. Halatchev

This paper treats the spatial aspect of mine sequence optimization, revealing it in the context of determining the optimum number of cutbacks of an openpit mine. Cutback mining is currently a dominant method in the mining of base and precious metals. It is based on a pseudo-economic discretization of the pit space using advanced pit design algorithms. The result of implementing such an approach of pit design is the generation of pit shells, which need to be grouped into an optimum number of cutbacks to maximize project value. In this paper, the development of a mathematical solution of this problem using combinatorial analysis is presented. The solution provides a multivariate investigation of the optimum mine sequence with the implementation of a method for production scheduling optimization that uses Net Present Value (NPV) as a criterion for assessing the economic efficiency of mine sequencing. A case study using the conditions of a hypothetical openpit gold mine is provided to illustrate the applicability of the approach. The results obtained reveal the complex nature of NPV variation as a function of the cutback geometry.

Jan 1, 2015

By Felicia F. Peng

The manganese removal from aqueous solution containing high Mn2+ concentration by adsorption and oxidation was studied using manganese oxide particles as the adsorbent. The operating parameters including pH, flow rate, initial manganese concentrations, and oxidant dosage affect the performance of Mn2+ removal were evaluated in a laboratory packed column. In the multi-column adsorption tests, each additional column doubled the time for complete manganese removal. No further decrease of pH was also observed once it was lowered to pH 4.5 to 5. This finding implied the possibility of complete high manganese removal without further pH adjustment during adsorption. Oxidation of Mn2+ by dissolved oxygen was found to be insignificant for manganese removal for high Mn2+ concentration. Adsorption was the predominated mechanism involved with manganese removal. Extremely low H+/Mn2+ stoichiometry compared to the reported values was measured. These low values suggested that different adsorption mechanisms such as chemisorption other than H+/Mn2+ ion exchange might play an important role at low pH. This paper presents the quantity and explanation of the results obtained for the mechanism of adsorption and oxidation of high concentration manganese on the manganese ore particles.

Jan 1, 1997

P&H MinePro Services Canada is supplying Syncrude Canada three more of its model4100BOSS electric mining shovels. The shovels will be delivered during 2003. Syncrude’s oil sands operations already use five P&H shovels. The first 4100BOSS shovel was commissioned at Syncrude’s operation in northern Alberta, Canada in October 2001. The unit loads more than 9 kt/hr (10,000 stph) of unblasted oil sands. Since it began operation, the 4100BOSS has shown a 28% production increase over the four P&H 4100TS shovels also on site.

Jan 1, 2003

By C. J. Bise, D. A. Poukhovski

Two integral components of the 30 CFR 48 training requirements mandated for new miners, newly employed experienced miners, and the annual refresher training of all miners are hazard recognition and prevention of accidents. In these categories, instruction shall include the recognition and avoidance of hazards present in the mine, and a review of accidents and their causes. Unlike instruction preparation for fact-based material, program development for hazard recognition places a particular challenge before safety-training specialists because they are often limited in their ability to adequately gauge the trainees' levels awareness prior to training. Further, they must also assure that the training is relevant, and it is presented in a thought-provoking manner. Computer-based instruction is particularly well suited for assisting trainers in developing hazard- recognition topics because it can be used in pre-training and post-training modes for assessment of training effectiveness, in addition to use as a presentation tool. Therefore, this paper will present a recent approach developed at Penn State to apply this technology for assessment and instruction of accident prevention through hazard recognition, with an application prepared for surface coal mines.

Feb 24, 1997

By Miles T. Stephens, Felipe Calizaya, Jacob O. Kingston

Currently, the Bear Canyon Mine is facing the challenge of excessively high coal and rock temperatures in one of its headings. In Mine No.3, the air temperature at the 6th Right panel reached 36.4ºC and the coal 83.9 ºC. Due to these severe work conditions, the mining plan has been altered by changing the mine direction to avoid the high temperatures. To investigate the problem, drill holes were developed from the entries and the rock temperatures monitored using K-type thermocouples. The measurements confirmed the existence of localized “hot spots” in the mine. This paper presents a summary of ventilation surveys that were conducted in this mine. It includes the results of coal and rock temperature measurements from drill holes, interpretation of results using a heat flow simulator and the identification of hot spot areas. It also includes a summary of methods that were developed to reduce the hazard and control the problem.

Jan 1, 2005

By J. D. Morgan

Demand for nonfuel minerals depends on the overall state of the economy, which steadily improved each quarter in 1984. New housing starts rose to 1.8 million units. Automakers turned out about 15% more cars (7.8 million) and 30% more trucks (3.1 million) than in 1983. Nevertheless, many domestic mineral operations experienced difficulties in 1984. This resulted from import competition greater use of newer engineered materials, emphasis on multi-unit housing and downsizing of motor vehicles. About 15% of our energy was imported. This in cluded $36 billion worth of crude oil and $22 billion in refined products This added significantly to the overall merchandise trade deficit of $12; billion. On the bright side for mining, coal production rose 14% to 810 Mt (890 mil lion st). Three-fourths o: the coal was burned to generate electricity and more than half of our electricity was derived from coal-burning plants. With the exception of a few large-bulk, low-value raw minerals, most minerals move relatively freely in world trade. The strong dollar encouraged imports and made exporting more difficult. Consequently, our nonfuel minerals trade deficit rose 60% to $19 billion, reflecting imports of $39 billion and exports of $20 billion. There were increased pressures from some major segments of the minerals industry for some form of import protection. But President Reagan said, "Our goal is a system of free and fair trade in goods, services, and capital. We will work toward this goal through both bilateral and multilateral trading agreements." The US minerals industry consists of domestic mines, concentrators, smelters, refineries, mineral manufacturing plants, and recyclers. It also includes many wholly- or partially-owned operations in many parts of the world, providing employment and income for US citizens and others as well. Compared with 1983, the value of US raw nonfuel mineral output rose 8%, to $23 billion. The $253 billion worth of goods processed from this crude mineral output was a 14% increase. Major Metals Raw steel production - a major indicator of both material use and mineral production-rose 10%, to 84 Mt (93 million st). This stimulated a 36% rise in domestic iron ore production, to 52 Mt (57 million st), about 98% pelletized. Iron ore imports rose 44%, to 14 Mt (15 million st). Despite the increase of steel production, output remained well below levels of just a few years ago. For example, 1984 production was still 23% less than in 1981. Raw steelmaking capacity remained steady at 122 Mt (135 million st). The industry continued to cite steel imports as a major reason for low domestic capacity. In December, pacts with seven leading steel exporting nations were announced. This is an effort to reduce import penetration to about 18.5% of the domestic market. Domestic producers of bulk ferroalloys of chromium, manganese, and silicon operated at about 50% capacity. The US mined no manganese or chromium. Only a small quantity of ferronickel was produced from domestic laterite mining in Oregon. Molybdenum production, at 45 kt (49,500 st), rose threefold. Mine shipments of tungsten, another mineral tied to steel

Jan 5, 1985

By John S. Brock

During 1964 and 1965 a mineral exploration program was carried out over an area of approximately 250 square miles, located in the Anvil-Vangorda Creek area of east central Yukon, 125 miles northwest of Whitehorse. The Vangorda deposit, a massive lead-zinc sulphide body discovered in 1953, was centred in the area proposed for exploration, a northwest trending belt located between the southwestern flank of the Anvil Range and Pelly River. Exploration for base metals in the remote Anvil area had previously been restricted by poor metal markets in the late 1950's. Regional geologic information was also limited except for publication of a scale 1 inch to 4 mile map by the Geological Survey of Canada in 1961. To effectively explore this area, a combination of geophysical and geochemical methods were essential due to extensive overburden cover varying in depth from a few feet to over 300 feet. (Figure (i) Key Map) Dynasty Explorations initiated the first comprehensive regional exploration program in the Anvil area, utilizing saturation prospecting methods employing geologic, geochemical and geophysical methods. The program involved an approach demanding continual modification of technical and physical logistics. After a total of 12 months of field work involving an expenditure of approximately $450,00, massive sulphides were discovered which subsequently proved to be an economic orebody. Thirteen properties had been acquired and explored. Ten separate geophysical anomalies had been outlined by a combination of magnetic, electric and gravimetric survey techniques of which five were tested by rotary drilling and two by diamond core drilling. The discovery of the Faro deposit was a direct result of this program.

Jan 1, 1971

By R. Gunda

Due to the rapidly increasing production rates and deepening of mine working areas, there is a drastic rise in the number of thermal issues to be addressed for maintaining a safe mine environment. As high temperatures and humidity in underground mines could affect the health and performance of workers, and ultimately the production rate, it is necessary to provide a properly controlled safe environment. The backfilling of stopes in metal, non-metal mines results in different thermophysical properties for the hanging, side and foot walls, modeling of which is not provided by any existing mine climate simulation software. This paper presents the modeling of such a single stope using the MULTIFLUX (MF) software, developed at University of Nevada, Reno. A special case is presented in this paper, where a case study from the Homestake mine in the US with a drift and ramp connected to a stope with high Virgin Rock Temperature (VRT) and various spot heat sources is modeled in MULTIFLUX and CLIMSIM, and the results are compared against each other. Another case is presented in which the stope of the previous cases is modeled with walls, each having a different set of thermophysical properties. These results are compared with the former results to analyze the effect of anisotropic properties.

Jan 1, 2011

By T. Yegulalp, R. Farrauto, A. Belova, M. Castaldi

Calcium oxide, with its ability to capture and store carbon dioxide, is emerging to become an important tool in carbon management. Calcium oxide can be used reversibly to capture carbon dioxide in situ and then be regenerated to produce a pure stream of carbon dioxide ready for sequestration; the Zero Emission Coal Alliance technology utilizes this property of calcium oxide to generate emissions-free electric power from coal. The reaction of calcium oxide with carbon dioxide resulting in thermodynamically stable carbonate is well understood; however, the efficiency of this reaction is limited by the diffusion of gases through bulk calcium oxide and through a layer of carbonate formed on the surface. In addition, the regeneration of calcium oxide is an endothermic reaction and is favored at high temperatures. The purpose of this paper is twofold: first, to address the diffusion limitation, a thin layer of calcium oxide, supported on a high surface area material, is studied thermogravimetrically to demonstrate the physical adsorption of carbon dioxide on calcium oxide. The adsorption is to take place at temperatures lower than required to form calcium carbonate.

Jan 1, 2007

By T. H. Chan

As the University of Hong Kong and their advisors planned their new Centennial Campus it became clear that they would have to re-provide existing water reservoirs on an adjacent site with new salt water reservoirs located underground in two new caverns. The existing reservoirs are owned by the Water Supplies Department who provide salt water for sanitary flushing and a separate potable water supply for regular use. Although underground reservoirs had not previously been adopted locally, the planning has been completed to a tight schedule and the construction is well advanced. The need to preserve historic buildings imposed constraints, as did the requirement to minimise potential construction nuisance for the local community and environment. This paper presents the background to the project and the work carried out to develop an innovative, sustainable and environmental acceptable solution. Construction progress to date is also presented.

By F. Rudloff, C. Karageorgos, J. Moyo, I. Boadi, M. Struble, B. Lumsden

Over it’s more than 100-year history, the Kennecott operation has often been at the forefront of innovation; driven by the demands of the lower grade ore-body and the higher costs of operating in the US where wages are generally higher and regulation more restrictive. One way of reducing operating costs in c/lb is to increase the lbs produced at minimal cost. Despite the relatively coarse grind at Kennecott - about 30% >150μm, approximately 20% of the Cu lost to tail is liberated chalcopyrite in the <20μm fraction, and about 30%-40% in the <37μm fraction. In 2020 Kennecott undertook a detailed plant scale test of the magnetic aggregation technology to increase copper recovery by reducing fine copper losses. A paired statistical plant test of magnetic conditioning on one rougher line showed a 1.12% increase in Cu recovery to 97% statistical confidence. The next challenge, unforeseen at the start of the project, was the fabrication and transportation to site of the equipment for the three remaining rougher rows, during the severe supply-chain constraints of the Covid pandemic in 2021. This resulted in delays and unforeseen costs as world-wide transportation became chaotic, particularly transportation via west coast USA. Nevertheless, the project was completed and commissioned, with only minor delays and cost increases, due to a flexible approach to overcoming the hurdles encountered.

Feb 1, 2023

By William R. Yernberg

The Cripple Creek & Victor Gold Mining Co.(CC&V) celebrated completion of a two-year, $168.5-million expansion and capital improvement program. An open house celebration was held in the historic mining town of Victor, CO on Oct. 4, 2002. Hundreds of townspeople, the press and other invited guests from the mining industry joined the employees of CC&V in the celebration. The event included mine tours, company displays and a barbecue picnic, complete with a country and western band. The Cresson Mine is located about 40 km (25miles) west of Colorado Springs, CO between the towns of Cripple Creek and Victor. The mine is the only large-scale gold mining operation in Colorado and now employs about 300 (ME, October 2001, pp.21-28). The operation is a joint venture between Anglo-Gold (Colorado) (67%), based in Greenwood Village, CO, and Golden Cycle Gold (33%), based in Colorado Springs. CC&V is managed by AngloGold North America. AngloGold North America is the U.S. subsidiary of AngloGold, the world’s second largest gold mining producer. AngloGold is based in Johannesburg, South Africa.

Jan 1, 2002

Considerable attention has been given to the restoration of low-level radioactive (<1000 pCl/g) sites contaminated during the early years of the atomic energy program. Current clean-up activities which involve the relocation of contaminated soils to licensed disposal sites have been shown to be very costly due to the large volumes of soils which must be excavated, transported and stored. Recent characterization studies conducted at Virginia Tech suggest that the volume of soil requiring disposal can be greatly reduced using mineral processing techniques such as classification, density separation and froth flotation. This article discusses the application of these technologies for soil remediation and describes a conceptual flowsheet for treating soil samples from two contaminated sites.

Jan 1, 1997

By Bhaskar B. Thapa

The design of the Caldecott 4th Bore, located along State Route 24 in Oakland, California, is based on the principles of the New Austrian Tunneling Method (NATM). Typical NATM initial support design practices used in Europe were adapted for this project to account for U.S. conditions and requirements, such as degree of experience with NATM construction, the prevailing contractual environment, and preferences for contractual simplicity. Key design features are: (1) support selection criteria based on ground behaviors and ground conditions; (2) a prescriptive design with allowance for support adjustments based on observations during construction; and (3) organization of support requirements into only four major support categories, while permitting some adjustment for variations in ground behaviors and conditions using a few subtypes and additional support measures.

By P. Zhang

A multiyear, comprehensive study of flotation reagents used in phosphate beneficiation was conducted. The study involved the evaluation of pure fatty acid compounds, comparison of various anionic collectors and testing of iso-acids. Various C12 to C22 fatty acids were tested as Florida phosphate collectors. The saturated fatty acids were found to be very poor collectors when using the standard conditioning procedure, whereas the unsaturated C16 to C22 fatty acids showed fair to good phosphate collecting ability. The C18 fatty acids oleic, impure oleic and linoleic and the C20 eicosenoic acid were shown to be the best phosphate collectors. The best flotation results were obtained using Liqro GA tall oil and oleic acid. Four isostearic/iso oleic acid type fatty acid collectors were compared with a commercial grade oleic acid and with Liqro GA tall oil as phosphate collectors using standard laboratory conditioning and flotation procedures. The most selective collector evaluated was Century 1108, a high isostearic acid-type reagent. However, it was concluded that this excellent-performing reagent was too expensive for commercial use. Overall, the most promising reagent was probably Century MO-5. This collector is essentially an iso-oleic acid/stearic acid mixture (not isostearic acid), and it costs much less. This program laid a sound foundation for developing single collector, all anionic flotation processes.

Jan 1, 2009

By SHANTAE LEE, ELAHEH TALEBI, Frank A. Drews, W. Pratt Rogers

Fatigue in mining operations is a serious issue and a significant contributor to incidents and accidents. While mine operators are using or introducing new technology to monitor operator fatigue, there is little work that focuses on the subjective experience of fatigue and the use of fatigue monitoring technology. To investigate this issue, eight focus groups with a total of 44 operators of heavy haulage equipment working for two mining companies in the Mountain West of the USA participated in 1-h focus groups. The topic of the focus groups was the experience of operator fatigue and issues surrounding fatigue at the workplace. The results of the content analyses suggest that operators are well aware of the signs of fatigue, and that they understand the severity of these signs as well. In addition, they are aware of the effect of fatigue on driving performance and are using a wide range of methods to manage fatigue. Finally, based on participants’ assessment, current fatigue monitoring systems lack face validity and reliability and are perceived as not being effective. The results of this study emphasize the importance of a socio-technical systems perspective in the context of miner health and safety management. Only such a comprehensive perspective can result in improvements that are sustainable.

Jun 17, 2020

By Luke Clarkson, David Williams

The intent of this paper is to provide overview context to allow broader understanding of conventional tailings dam failure mechanisms. The research leverages global knowledge, experience, and data collection and interpretation for the safe and controlled management of the geotechnical stability of a tailings storage facility. The motivation for this review is to facilitate transparent access to tailings dam background and understanding. This paper addresses the core understanding of geotechnical failure mechanisms, and how these eventuate to instability and failure of tailings dam structures. This research focuses on foundation failure, internal erosion and piping, overtopping, seepage, seismicity, and slope instability and provides insight into what factors contribute to failure, how failure progresses due to such failure, anticipating and monitoring for the aforementioned failure modes, and designing to mitigate their risk.

Feb 15, 2021

By Bhawani Singh, A. K. Dube, B. Singh

At least three hydroelectric tunnels constructed during the last decade through the lower Himalayan region in India have met with serious problems of supporting in squeezing ground conditions. Steel ribs under went intolerable deformations requiring rectification to provide space for concrete lining which delayed the projects inordinately. In an attempt to choose a rational method of predicting rock load, the authors have compared rock loads estimated from various classification systems and elasto-plastic theory with observed values. The deficiencies of the classification systems have been highlighted to show that the combination of elastoplastic theory and tunnel instrumentation programme provides better guidelines for the design of tunnel supports in squeezing ground conditions.

Jan 1, 1981

By J. D. Miller, C. L. Lin

Filtration of fine particles involves filter cake formation and removal of surface moisture by drawing air through the porous structure. Accurate assessment of the transport properties of porous media (in this case, filter cake) is of major importance in the development of improved filtration processes. Implications from these studies are important in the design and operation of filtration equipment in order to enhance the efficiency of this important solid-liquid separation process. The microstructure and connectivity of pore space are important features necessary to describe detailed fluid flow phenomena in filter cake during fine particle filtration. In this regard, 3D characterization of pore structure is essential. The pore structure has to be described by parameters which are of special relevance to the interpretation of fluid transport phenomena. These parameters should be based on directly measured variables of the pore system and not inferred from indirect variables (such as those determined empirically from transport processes) valid only for a particular pore structure. In this way fundamental relationships between pore structure and fluid transport at the microstructure level can be described. In order to achieve this level of sophistication the three-dimensional interconnected pore structure of filter cake must be determined. Study of fluid transport phenomena in filter cake using x-ray microtomography to characterize the complex three-dimensional pore geometry is discussed. On this basis the Lattice-Boltzmann (LB) method is used to simulate and to establish a fundamental relationship between pore microstructure and effective transport coefficients.

Jan 1, 2002

By Narendra N. Khatri, Michael Deutscher, Jozef F. Zurawski

Five sewer connections were required to divert Combined Sewer Overflow (CSO)from existing outfalls to an old underutilized large diameter brick sewer (the Easterly Interceptor). The connections were part of an on-going CSO control program by the Northeast Ohio Regional Sewer District (NEORSD) in the City of Cleveland, Ohio. Each connection was made by pipejacking and hand-mining a fiberglass-reinforced polymer (FRP) pipe through soft glaciolacustrine clays and silts. Jet grouting was utilized to stabilize the soils and fill the voids surrounding the interceptor prior to making the underground connection. Reinforced concrete liners were constructed inside the aging brick sewer to provide structural stability during ground improvements and connection work. The project also involved micro tunneling two approximately400 foot lengths of FRP pipe through soft ground using a slurry pressure balanced machine.

Jan 1, 2005