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By J. Noll, A. Miller, J. Volkwein, C. Pritchard

Hecla Limited, Magee Scientific and the U.S. National Institute for Occupational Safety and Health (NIOSH) combined efforts to evaluate an in situ air filtration system for use in an underground mine environment. The purpose of the collaboration was to determine the efficacy of such a technology for reducing the concentration of airborne diesel particulate matter (DPM), with the aim of improving air quality in underground hardrock mines. A secondary goal was to evaluate the use of an aethalometer as a means of real-time measurement of black carbon as a surrogate for DPM. The evaluation included measuring the DPM-capture efficiency of the filter when it was preloaded with dust. Toward this end, rock dust was introduced at the filter inlet to create a dust layer on the filter surface, with the intent of providing improved capture of the much smaller DPM particles. The filtration efficiency for DPM was assessed by comparing measurements of DPM taken at the inlet and outlet of the system, using both realtime and time-weighted-average approaches. The real-time measurements were performed with a Model AE33 aethalometer, and filter samples analyzed by the NIOSH 5040 method were used to assess the effects of the system on time-weighted-average concentrations of total carbon. Results showed a reduction in DPM concentrations in the range of 82 to 89 percent. While the calculated efficiencies based on the two different measurement methods were similar, the DPM levels reported by the aethalometer were higher, possibly due to differences in the performance of the size selectors used for the two methods: impactors versus cyclones. More research is required to develop a robust correlation between the two methods to support the use of the aethalometer in future mining applications. The advantages of the aethalometer are that it can measure and record DPM levels for weeks at a time and can be directly connected to a mine monitoring system, potentially at multiple locations. Ideally, such data can be used to initiate the startup of the filtration system should DPM concentrations reach an action level. This work demonstrated that in situ filtration systems, modified to collect DPM and coupled with real-time monitoring, show promise in reducing DPM concentrations in the mine environment.

Mar 1, 2017

By Raymond E. Langen

Uranium exploration in the Powder River Basin of northeastern Wyoming has been intensive since 1966 and in 1968 produced significant discoveries of reduced uranium ore by Humble Oil & Refining Company and others. Substantial reserves have been established in the area. High-grade carnotite ore was discovered in 1951 near Pumpkin Buttes in the central part of the basin (Fig. 1). Other mineralized areas were soon established from Pumpkin Buttes south to Monument Hill and Box Creek. Total production from these shallow oxidized deposits in the lower Eocene Wasatch formation was small. The AEC reports total production of 520,000 tons of ore averaging 0.19% U3O8. The authors are indebted to many people within Humble Oil & Refining Company and Esso Production Research Company for their assistance and guidance. SUMMARY AND CONCLUSIONS The Highland ore deposit, discovered in 1968, is a large uranium occurrence located in the southern part of the Powder River Basin. Uranium mineralization consists of sooty, black uraninite and coffinite coating sand grains and is concentrated along the margins of Tertiary fluvial sandstones. Uranium was transported by oxidizing solutions roving through the buried sandstones and spreading into less permeable channel-edge sandstones to form typical rolls and tabular deposits. Unaltered sandstones are light gray to gray-buff where the sandstones have been oxidized, the colors are various shades of red, yellow, and yellowish brown. An Oligocene tuffaceous source for the uranium is proposed; however, leaching of the arkosic and tuffaceous host sediments may also have provided a source.

Jan 1, 1971

By Crystal Poon, Paul Matlashewski, John Morkeh, Kathryn Dorfschmidt, Jose Carvalho, Chad Williams

Rockfall hazards are ubiquitous in mining environments making their control critical for safe mining operations. The complex processes involved in rockfall events necessitate a probabilistic modeling approach with well-calibrated material properties. The controls designed to mitigate rockfall hazards need to be reliable, efficient, and safe to deploy to meet the constraints present at an active mine. This paper presents an innovative solution to rockfall at Rio Tinto’s Bingham Canyon Mine. The solution incorporates the site-specific calibration and creation of a predictive rockfall model with the design, field testing, implementation, and monitoring of the rockfall controls.

By Crystal Poon, Paul Matlashewski, John Morkeh, Kathryn Dorfschmidt, Jose Carvalho, Chad Williams

Rockfall hazards are ubiquitous in mining environments making their control critical for safe mining operations. The complex processes involved in rockfall events necessitate a probabilistic modeling approach with well-calibrated material properties. The controls designed to mitigate rockfall hazards need to be reliable, efficient, and safe to deploy to meet the constraints present at an active mine. This paper presents an innovative solution to rockfall at Rio Tinto’s Bingham Canyon Mine. The solution incorporates the site-specific calibration and creation of a predictive rockfall model with the design, field testing, implementation, and monitoring of the rockfall controls.

By K. Zhang

Real option value (ROV) method is considered to be more practical and advanced compared to net present value (NPV) method in evaluating a mining project, in particularly when there is substantial uncertainty in the commodity market as well as possible operational flexibility embedded in the project. Usually, it may take months or even years for the commodity product to be available in the market after the mining activation decision is made. The impacts of postponing the delivery of commodity product on the mine?s ROV and NPV are assessed based on the proposed real option method. Postponing the delivery of the products leads to declined NPV and ROV compared to the non-postponing scenario and extended postpone results in higher lost values in NPV and ROV. For a mine with lower mining cost, by postponing the delivery, the exercising threshold of commodity price is lower because the mine owner anticipates that commodity price may rise during the time of postponing. A mine with higher mining cost requires a higher exercising price threshold to ?lock up? the profit when there is ambiguity of market situation due to the postponing of the delivery.

Feb 23, 2014

By Nikolaos Syrtariotis, Mark Berger, Timothy O’Brien, Vojtech Gall

The Northeast Corridor Superconducting Maglev Project (SCMAGLEV) entails construction of a high-speed train system between Washington, DC and New York City, with the first leg between Washington and Baltimore, MD. This innovative project will shorten travel times between Washington DC and Baltimore to approximately 15 minutes, and connect Washington, DC to New York City in under an hour. In 2021 the draft EIS is expected to be issued for comment with a Final EIS/ROD anticipated by early 2022. This paper provides an update on the project as presented in Gall et al. (2020) and discusses the economic and environmental benefits, preferred alignment alternative, preliminary staging and launching of the TBMs for construction, and preliminary station design.

Jun 13, 2021

By J. P. De Carvalho, R. Dimitrakopoulos

An actor-critic reinforcement learning approach is presented to improve the production of an industrial mining complex by defining shovel allocation and adapting the short-term plan given grade-control decisions. Blasthole data updates the simulated orebody models, which are input into a stochastic grade-control method based on a spatially constrained clustering approach that minimizes the profit-loss function. These aspects are embedded in a discrete-event simulator that defines the material flow from faces to processors. A case study at a copper mining complex shows the methods’ ability to adapt to new information, improving the quality of the material feed and increasing cash flow by 23% compared to a baseline case.

Jun 25, 2023

By J. H. Desautels

The modern coal mining industry is subject to a vast array of regulations affecting virtually all aspects of its operations. Probably the most significant over-sight role involves the Office of Surface Mining Reclamation and Enforcement (OSH) established by the Surface Mining Control and Reclamation Act, or SHCRA.1 Although complying and coping with SHCRA can be difficult for coal operators, this complex regulatory process has helped insulate the industry from ongoing efforts to extend regulation under the Resource Conservation and Recovery Act, or RCRA, 2 to aspects of the mining industry in general. The Environ-mental Protection Agency (EPA) has struggled with regulation of mining wastes under RCRA since the mid-1970's, but RCRA itself places most coal mining wastes firmly under the control of OSH and SHCRA. Despite the general exemption from RCRA regulation for waste materials that result from extraction and processing of coal itself, there may be circumstances under which coal mining operators could find themselves subject to regulation under RCRA or a number of other statutes administered by EPA. This paper will review briefly the history of mine waste regulation under RCRA, as well as touch on the policy decisions that led to the exemptions from RCRA regulation. The paper will summarize coal waste requirements under SHCRA, and also will review what operations at coal mines need to be controlled, in order to avoid potential liability under RCRA. In addition, it will mention requirements under other federal laws, including CERCLA, or the "Superfund" law,3 and describe how they may impose restrictions or liability on coal operations for waste or other materials commonly found at surface and underground coal mines.

Jan 1, 1993

By J. A. Restrepo, K. D. Luxbacher

"The U.S. underground coal mining industry has recently seen the occurrences of several multifatality events that have interrupted an otherwise steadily improving safety record. These events transpired even with an unprecedented level of government regulations and safety technologies. These events may indicate that current safety practices have reached a level of diminishing returns. Risk management, a safety approach that has been successfully applied in numerous industries including mining, may provide a means to overcome this plateau. Riskgate is an Australian mining risk management program that may be successfully applied in the United States. However, fundamental differences between the Australian and U.S. coal mining industries prevent direct implementation. This paper discusses aspects of the Riskgate body of knowledge that require adaptation for its application in the United States. IntroductionThe underground coal mining industry in the United States has recently seen the occurrences of several high profile, multifatality events. These events transpired in the midst of an unprecedented level of government regulations and modern safety technologies. The recent increase in fatal events in conjunction with minimal declines in fatal and nonfatal injuries over the past decade may signify that current safety practices have reached a level of diminishing returns. In order to surpass this plateau, a modification to the manner in which the mining industry approaches worker safety may be warranted.The implementation of a risk-management- based approach may potentially provide a means for not only surmounting the current safety stagnation but also for achieving the long-desired objective of zero harm.Riskgate is an Australian risk-management- based body of knowledge that shows great potential for application in the United States. This paper discusses aspects of the Riskgate body of knowledge that require adaptation for the U.S. mining industry. The proposed adaptations are based on differences in operating practices and government regulations. This discussion will focus on the three major U.S. risk areas of explosion prevention, ground control and moving equipment."

Jan 1, 2015

By Georgene Renner, William R. Yernberg, Steve Kral

Advanced Terra Testing (ATT)is a full-service geotechnical testing laboratory. It specializes in rock and soil mechanics and geosynthetic materials testing. ATT provides services to the global mining industry. The company has performed more than 1,000 projects for more than 300 commercial and government clients. Services include coal pillar design testing, leach pad material and performance testing, tailings pile consolidation testing and closure and remediation services. Rock and soil mechanics tests include unconfined and triaxial strength, shear and tensile strength, permeability, index testing, consolidation, liquifaction potential, elastic moduli determinations, heap height versus percolation rate, long-term batch testing and dynamic loading tests.

Jan 1, 2003

By N. Magdalinovic

Generally speaking, erosion, as a process which entails degradation of surface layers of earth under the influence of the mechanical energy of surface waters, and from the point of view of biosphere sustainability, is a harmful process. This is absolutely true when agricultural and forest areas are concerned. However, if erosion is viewed selectively, this general definition about its harm raises serious questions. In other words, the erosion which takes place in the terrains where there is no vegetation because of the geological composition of the soil, does no harm. On the contrary, if the mineralogical composition of such terrains is characterized by a presence of precious and rare metals, erosion can be very useful. It contributes to the creation of new alluvial deposits of these metals in the waters in the plain land. It is here that torrents from hills come down and cause erosion. And finally, if there were no erosion, there would be no renewable deposits of gravel and sand.

Jan 1, 2007

By Ryan Dr.

In December 1988 Phelps dodge corporation brought an underground gold mine into production in the republic of Botswana. The mineralization is associated with steeply dipping shear zones in Archean greenstones of the Tati Schist Belt. The gold is intimately associated with sulfides and is refractory in nature. The deposit is being exploited by underhand open stoping methods. Vertical and inclined shafts are used to hoist the ore to surface where it is treated by conventional crushing, milling and flotation, followed by fluid bed roasting with CIP elution and carbon regeneration. Adjacent deposits are being explored with a view to increasing production. Legal and taxation aspects of operating in Botswana are discussed.

Jan 1, 1989

By Rambabu Pothina, Rajive Ganguli

The economics of a mineral-processing circuit is dependent on the numerous sensors that are critical to optimization and control systems. When a sensor goes off calibration, it results in errors that can have a severe impact on plant economics. Classical statistical approaches fail to detect when errors are “subtle,” unless they grow and become large enough to be “gross,” whereas methods based on signal processing and artificial intelligence fail in dealing with the complexity of process fluctuations. Due to the sheer volume of sensors, undetected errors are not remedied until the next calibration, which on average are a year apart across all industries [1]. This research aims to detect such subtle errors (2 percent bias) in shorter time spans of about a month — rather than wait for errors to grow — using innovative data-mining techniques and algorithms.

By G. Meschke

"This paper reports on computational and experimental research, performed at the Collaborative Research Center “Interaction Models for Mechanized Tunneling” at Ruhr-University Bochum, Germany. Research covers a broad spectrum of topics relevant for mechanized tunneling in soft soil conditions. This includes advances exploration methods and models for the characterization of the in-situ ground conditions, the interaction of the face support and the tail gap grouting with the porous soil, multi-scale models for the design of fiber reinforced segmental linings with enhanced robustness, computational methods for the numerical simulation of the tunnel advancement, the soil excavation and the material transport in the pressure chamber, logistics processes and risk analysis in urban tunneling.INTRODUCTIONMechanized Tunneling has proven itself as an economical and flexible construction method that continues to undergo a dynamic evolution process. Shield diameters continue to increase, and the application range of tunnel boring machines is being extended to an ever-increasing variety of geotechnical conditions. In order to maintain economic viability and to ensure an environmentally friendly construction process, realistic and reliable numerical models are required in order to make informed decisions during planning and construction. To provide a reliable numerical prognosis, it is necessary to accurately assess and understand the interactions between the components involved in mechanized tunneling with the surrounding site, the ground, and any pre-existing structures. Heterogeneous geological conditions and often only approximated ground parameters create, in contrast to other engineering projects, special demands. This necessitates new insights to new problems that can only be effectively solved through truly interdisciplinary research. To address these challenges, the German Research Foundation (DFG) has established the Collaborative Research Center “Interaction Models for Mechanized Tunneling” (SFB 837) at the Ruhr-University in Bochum in 2010. Collaborative Research Centers are interdisciplinary scientific research groups in which cooperative research is conducted under the umbrella of a central research theme. With a research budget of ca. 10 Million Euros for the second 4-year funding period, and a research team composed of 13 project leaders along with approximately 35 scientific assistants the SFB 837 is currently one of the largest research groups conducting fundamental research in tunneling related topics worldwide.RESEARCH TOPICSThe research topics of the SFB 837 encompass a number of relevant planning and construction related aspects in mechanized tunneling (Figure 1). These research themes are each supported by computational models and laboratory investigations and are all included in an SFB overarching Tunnel Information Model (TIM). Interaction groups integrate and combine the results of different submodels through prototypical cause-and-effect relationships, and through the analysis of the Wehrhahn metro line (WHL) project in Düsseldorf, which has been adopted as the reference project for the SFB 837."

Jan 1, 2016

By D. Arku

The increased use of sensors to facilitate automation has led to an explosion of data. As data sets grow in size, their use becomes more complex. Therefore, there is an incentive for reducing the size of the datasets, as long as this does not compromise information gleaning. With this in mind, this project explored basic aggregation as a viable alternative to amassing large amounts of data. The goal of the project was to determine if one would arrive at different conclusions had they analyzed aggregated data instead of raw data. In a mine, operational data is typically used for tracking process statistics, correlation between factors, autocorrelation and multivariate models (for a factor of choice). Therefore, this project compared results from such analyses when it was conducted with aggregated data (AD) with the results of analyses conducted with raw data (RD). The data consisted of one-minute-apart readings from a semiautogenous grinding (SAG) mill on the horsepower, feed rate (tons per hour), rotations per minute (rpm), noise, recycle (tons per hour), density (% solids) and bearing pressure (psig). This data was aggregated by averaging five and 10 continuous (one-minute) observations. Changes in statistical measures between the two approaches were typically within 5% of each other. Differences in correlation coefficients between RD and AD(s) were also within this range. Autocorrelations present within RD were preserved in AD, as long as the time lags were scaled for the amount of aggregation. Regression and neural network models were also developed for power consumption. The prediction performance of developed models was similar whether one used raw data or aggregated data. Overall, it appeared that aggregating the data based on 5- or 10-minute time spans would not have resulted in conclusions (from simple or complex analyses) being different from using raw data. In other words, whether one had used raw data or aggregated data, the conclusions would have been the same, suggesting that time domain aggregation, a common industry practice, is a good alternative to storing high-density data in this case.

By M. Guzman, M. Romero, S. Bravo-Thais, M. Flores

The phytoremediation method is proposed to recover valuable metals from polluted soils. In this sense, the objective of this research is to determine if it is possible to use native plants in the recovery of precious metals from abandoned mining liabilities. The tailings samples containing Au and Ag were acquired from the northern region of Peru. Two native plant species, Stipa Ichu and Cortaderia Nitida, were used. Results show that Au was recovery around 19% (1.52 mg/Kg) and 25.43% (1.78 mg/Kg) by using Stipa Ichu and Cortadeira Nitida, respectively. Besides, Ag had a better recovery in the Stipa Ichu reaching a value of 6.83% (0.628 mg/Kg); in contrast, Cortadeira Nitida had an efficiency of 3.6% (0.814 mg/Kg). Bioaccumulation, bioconcentration and translocation factors were calculated by determining the concentration of precious metals in the roots and aerial parts of each plant. Results show that Stipa Ichu had a greater capacity of hyperaccumulated Ag compared to Au; while Cortaderia Nitida tended to have a better performance for Au. In conclusion, both plants are recommended for phytoremediation of mining liabilities.

Feb 1, 2023

By Elnaz Saminfar, Jae Bateman, Eric Westergren, Mark Trim

This paper presents a case study of two major Australian infrastructure projects that used digital engineering to facilitate design delivery: WestConnex Project (Rozelle Interchange), and Sydney Metro West (Eastern Tunnelling Package). The paper presents project overviews and building information modeling (BIM) execution and focuses on modeling techniques, software utilization, data management strategies and how the digital models helped the design-build team mitigate impacts to schedule by identifying clashes between disciplines before the execution of work. Finally, it demonstrates the positive and transformative impact of digital engineering on the design and construction of large underground infrastructure projects and highlights its role in asset management throughout the project lifecycle.

Jun 23, 2024

By M. Nambiar

Due to the remote locations of mining projects and the need for long transmission lines to provide electrical power, mining sites often operate with poor network power quality and low short-circuit capacity. To cope with this situation, more and more mining operators are considering the installation of appropriately designed synchronous condensers together with power factor correction and harmonic filter systems (PFC & HFS). The installation of such power quality equipment is viewed as a technological advancement in the mining application. An adequate level of short-circuit power is essential and has to be ensured for the safe and reliable operation of especially large cycloconverter-driven gearless mill drive systems (GMDs) used for grinding. This paper explores the impact, technical advantage and reasoning for the selection of this advanced hybrid technology to cope with the power system challenges of future mining projects. It also delves into the potential problems and how to address them.

By A. E. Halim, J. F. Brune

Debate continues over whether barricading in refuge chambers is a good strategy to survive entrapment emergencies in underground coal mines, in particular fires and explosions. Unlike U.S. coal mines, Australian coal mines are not required to use refuge chambers and, instead, have adopted a strategy that focuses on instructing and training miners to self-escape to the surface. This paper analyzes the merits and problems of using refuge chambers or self-escape to the surface to manage emergencies in fires or explosions in an underground coal mine. We found that using refuge chambers may not be the best strategy during extensive fires or when multiple explosions occur. In these situations, mine rescuers are unlikely to be able to extract miners who are sheltered in chambers and, conversely, self-escape may save more lives than sheltering. Chances for successful self-escape are further improved by regular, externally assessed training such as the level 1 emergency exercises required in Queensland, Australia. These exercises put pressure on mine operators to ensure and maintain the effectiveness of their emergency management system.

By J. N. Cox

Coal preparation is based on the properties of noncombustable materials (impurities) in coal being different from the organic constituents. The most commonly used property difference is density, via its affect on settling rates; and either gravitational or centrifugal forces can be used to remove impurities. However, examination of various particles settling rate correlations shows that at smaller sizes, particle drag becomes a very important factor. Classification, based on differential settling rates, becomes impractical and some property other than density must provide the basis for fine coal cleaning. Froth flotation and agglomeration employ differences in surface properties to clean coal. These methods are very successful except that the oxidized surface of a pyrite particle is somewhat hydrophobic and will tend to be collected with the organic portion of the coal. Surface property cleaning techniques have not been very effective in rejecting sulfur, except for two-stage flotation.

Jan 1, 1984