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By S. C. Sethi

The WIPP (Waste Isolation Pilot Plant) Project near Carlsbad, New Mexico, is a research and development project sponsored by U.S. Department of Energy, designed to demonstrate the safe containment for disposal of radioactive waste. A mine (repository) is currently being developed 2150 feet below the surface, in a thick salt bed which will serve as the disposal medium. Provision of a proper ventilation system at the WIPP Project is a major priority of those responsible for its design, management, and operations. As an ongoing effort towards this goal, it was decided to simulate the mine's ventilation system using Dravo's MINEVENT computer program. Specifically, the work included the development of the following simulation models: 1. Simulation of the current ventilation system 2. Simulation of the designed ventilation system for the following modes: o Mine Construction mode/shift o Waste storage mode/shift o Fire or exhaust filtration mode These computer models are useful in solving complex ventilation problems likely to be encountered in an R&D project, like WIPP. They are particularly helpful for the development of contingency plans to incorporate during emergency situations, such as fires, fan stop- pages, radiation leaks, etc. Also, they can be utilized when considering expanding certain underground areas to ensure the availability of adequate ventilation.

Jan 1, 1986

By K. Chief

American Indian lands contain a vast amount of renewable and non-renewable resources that have consequently been mined (Smith and Frehner). Therefore, it is understandable that tribes are concerned about environmental impacts from mining and their ability to minimize and mitigate these impacts. This has created a need to better understand mining and its environmental impacts. The University of Arizona Superfund Research Program Mining educational modules developed educational modules for tribal colleges focusing on environmental impacts of mining, remediation of mining wastes, and sociocultural impacts of mining. Educational modules are independently packaged units of study designed to enhance the learning process and can be modified and adapted to different learning scenarios and objectives. In addition to providing specialized knowledge, the modules feature hands-on activities, incorporation of technology, student involvement, discussion, and exchange of ideas. Modules will aim incorporate traditional ecological knowledge and approaches that promote effective science learning for native students. Modules are designed to augment existing associates of science programs (e.g. biology, chemistry) currently offered at tribal colleges and can be modified for use in K-12 education and for non-tribal audiences.

Feb 23, 2014

By Renfeng Song, Shaoyan Wang, Zhiqiang Zhang, Ke Guo

Leaching titaniferous magnetite concentrate with alkali solution of high concentration under high temperature and high pressure was utilized to improve the grade of iron in iron concentrate and the grade of TiO2 in titanium tailings. The titaniferous magnetite concentrate in use contained 12.67% TiO2 and 54.01% Fe. The thermodynamics of the possible reactions and the kinetics of leaching process were analyzed. It was found that decomposing FeTiO3 with NaOH aqueous solution could be carried out spontaneously and the reaction rate was mainly controlled by internal diffusion. The effects of water usage, alkali concentration, reaction time, and temperature on the leaching procedure were inspected, and the products were characterized by X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy, respectively. After NaOH leaching and magnetic separation, the concentrate, with Fe purity of 65.98% and Fe recovery of 82.46%, and the tailings, with TiO2 purity of 32.09% and TiO2 recovery of 80.79%, were obtained, respectively.

Jun 16, 2021

Semisoluble salt minerals are characterized by their ionic bonding and are distinguished from soluble salt minerals by their limited solubility in water. One group of semisoluble salt minerals being considered is the alkaline earth salt minerals, including fluorite (CaF2), calcite (CaCO3) and apatite (Ca5F (PO4)3), as well as celestite (SrSO4) and barite (BaSO4). Another group of semisoluble salt minerals being considered is the rare-earth salts, which include bastnaesite ((Ce, La) CO3F), monazite (CePO4) and xenotime (YPO4). Surface chemistry features of these selected semisoluble salt minerals are discussed with respect to flotation separations. First, the surface chemistry features of alkaline earth semisoluble salt minerals are reviewed, and then the surface chemistry features of rare-earth semisoluble salt minerals are examined. The discussion includes electrokinetic behavior, wetting characteristics and collector adsorption.

By Aijuan Zhang, Liang Zhao, Yutao Wang, Yu Bao

In the green backfilling mining of underground coal mines, gangue in a coal seam is used to replace and fill goafs. However, the gas drainage time changes in the amount of gangue output and order in the extraction sequence of stope blocks, thereby changing the production output. A multi-objective integer programming model was proposed to solve this based on an improved non-dominated sorting genetic algorithm. The results show a feasible gangue filling rate can be found and the extraction sequence for a long-term planning time is optimized. It increases the planned annual output by 26% and reduces equipment idle time.

May 23, 2022

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

By M. A. Georgiana

The Emerald Mine No. 1, located in southwestern Pennsylvania is presently owned and operated by Cyprus Minerals of Englewood, Colorado. High volatile bituminous coal is produced from the Pittsburgh No. 8 seam by both longwall and continuous mining methods. The coal is then mechanically cleaned on site utilizing a combination of heavy media separation and froth flotation methods prior to shipment to both the metallurgical and steam coal markets. The Emerald Mine is presently producing 2.8 million raw tons per year, while liberating approximately 6.5 million ft per day of methane. In light of the methane liberation rate, ventilation requirements have been significant and have always received utmost priority and consideration. Figure 1 shows the locations of the current and proposed shafts. Emerald utilizes two Joy (Model M120-58-880) axial vane fans on shafts No. 1, No. 2R, No. 3R. (one operational, one stand-by) The use of computer simulation of various ventilation networks was initially employed during the design stages (1975-1977) and has been utilized through the present. Obviously, the initial planning, under the ownership of Lykes Resources, was strictly theoretical. All the quantities were proposed and the resistances were based on prior simulations of other mines and mathematical formulas. However, once the mine was moderately developed, actual values were recorded and utilized. This procedure consists of: a) layout pressure and quantity points b) measure all air quantities where an air course splits

Jan 1, 1986

By C. A. Young

In-situ Fourier transform infrared/internal reflection spectroscopy (FT ?IR/IRS) has been extended to study oleate adsorption at a calcite surface. The birefringent and transmission limitations of calcite were overcome by using an appropriately designed optical setup and a near-infrared (NIR) spectrometer. An adsorption isotherm was determined at pH 9.2 and room temperature. Comparison with the fluorite/oleate adsorption isotherm determined by the same technique indicates that oleate abstraction by calcite can be as much as one order of magnitude larger than that by fluorite. Nevertheless, the hydrophobicity of the fluorite/oleate surface is greater for equivalent adsorption densities as indicated by contact angle measurements and flotation results. The monolayer region has been confirmed to be chemisorbed oleate at both calcite and fluorite surfaces. Furthermore, multichannel laser Raman spectroscopy (MLRS) showed that chemisorbed oleate at the fluorite surface undergoes a double-bond reaction with oxygen to form an epoxide/polyether complex. Such a reaction, however, could not be detected at the calcite surface. These phenomena are discussed in terms of the intrinsic surface properties of the mineral systems as well as the adsorption density and the cross-linking/polymerization reaction of the adsorbed oleate film.

Jan 1, 1993

The United States is being invaded... by foreign capital: marks, francs, pounds, yen, lire, riyals, you name it: On almost any given day the Wall Street Journal will contain a new report on a department store, newspaper, bank, hotel, agricultural land, supermarket chain, et a1 being bought into by overseas investment. Xenophobic reaction to this revised national condition has begun to set in. Several farming states have and are introducing legislation to monitor foreign land buying. In Congress a mandatory reporting requirement for foreign purchasing is currently under study. In a relatively short period the country has reverted from world leader- ship in overseas acquisition and involvement to become itself one of the prime investment opportunities in existence. Interestingly enough, one of the industries where this changed status has become most apparent and pronounced is within that small/regional/segmented/low value-to-weight bulk commodity enterprise ranked as the backbone of the nation's construction activity. U.S. cement making is not only undergoing internationalization in its ownership, but also in its product, equipment, and engineering expertise.

Jan 1, 1979

By W. C. Lacy

Traditionally Australia has been a leader in underground mining methods with world standards being established at Mount Isa, Broken Hill, Kalgoorlie, and Mount Lyell. With decline in higher-grade reserves and discovery of a multitude of near-surface oxide gold de-posits attention has shifted to bulk mining of low-grade gold ores by open pit methods, heap leaching and activated carbon recovery of gold values. The paper examines historical change in mining philosophy and the economic effects of isolation.

Jan 1, 1993

By E. Stemn

Incident investigation is of utmost importance in most high-risk industries. This study was undertaken to study the content of past investigation reports to determine the effectiveness of the incident investigations. The study uses a semi-quantitative method to assess the effectiveness of incident investigations in the Ghanaian mining industry by evaluating the quality of past investigation reports. The assessment tool consists of 5 elements with several indicators and rating scales for assessing the quality of an investigation report as a measure of the effectiveness of the investigation. The method was applied to 304 investigation reports of 3 Ghanaian large-scale gold mines, and the results correlated with incidence rates of the mines to determine if any relationship existed. The results showed that the mines differ significantly in the quality of their investigation reports, suggesting differences in the effectiveness of their investigations. In addition, the incidence rates of the mines negatively correlated with some elements of the assessment tool. In general, the method was found useful and revealed areas where improvement is needed. INTRODUCTION The importance of learning from incidents is well documented in the literature. For instance, some scholars regard learning from incidents as important for improving safety [1,2]. Thus, many organisations spend considerable resources in identifying lessons from incidents and subsequently on the process of improvement that follows the identification of lessons. It is therefore important for such organisations to determine the effectiveness of their learning from incidents processes, in order to identify specific areas where improvements are needed, so that interventions can be as specific as possible. The learning from incidents process models the plan-act-check-do approach of management systems, often consisting of four major stages, namely; data collection and incident analysis, planning interventions, implementing interventions and follow-ups and evaluation [3,2]. The investigating and analysis of incidents have been regarded as one of the vital stages of the learning process since it is the stage where lessons are identified [3,2,4]. It has also been noted elsewhere in the literature that results of the previous stage of the learning process are important for the next stage [3]. For example, ineffective incident analyses could result in the planning of ineffective remedial measures. One of the primary aims of incident investigations is to identify lessons from previous incidents which when implemented can prevent future recurrences or minimise the effects of future incidents. There is thus the need for organisations to assess the quality of their investigations periodically since it is one of the means they adopt to improve safety and the quality of remedial measures to some extent depends on the effectiveness of the investigations. Although previous studies [5,2] have assessed the effectiveness of the learning process, and some aspects of the learning process, such as incidents reporting, there is less focus on the effectiveness of incident investigations. The research described in this paper was therefore conducted to contribute to this gap, focusing more closely on incident investigation reports.

Jan 1, 2019

By S. M. Hossaini, M. Ataei, H. Moosavi

The abstract highlights the importance of pillar stability in underground coal mines and the influence of rock mass strength and joint orientation on pillar behavior. The study employs numerical modeling using the distinct element code (UDEC) to investigate the impact of these factors on pillar stability. The research considers different joint orientations and varying rock mass strengths, analyzing parameters like stress distribution, displacement, and failure patterns. The findings reveal that both joint orientation and rock mass strength significantly affect pillar stability, with specific combinations leading to reduced safety factors and increased deformation. The study concludes by emphasizing the importance of considering these factors in pillar design for safe and efficient mining operations.

Apr 4, 2022

By Orlando Oliveros

The Los Bronces Mine and Concentrator, one of the three operating units of Compania Minera Disputada de Las Condes S.A. (an Exxon Minerals Co. affiliate), is located in the high Andes of East-Central Chile approximately 70 kilometers northeast of Santiago at an elevation of 3,650 meters above sea level. (Figure 1). Santiago, the capital city of Chile, is located at an elevation of about 500 meters above sea level and enjoys a very mild climate, similar to some areas of California. At the mine site, however, extremely heavy winter conditions prevail occasionally, with very heavy snow and the resulting snow avalanches endangering installations and people. At the same time, ideal skiing conditions are found at the nearby ski resort of Portillo and Farellones. Mount Aconcagua, the highest mountain in the western hemisphere is only about 55 kilometers further to the northeast of the Los Bronces mine.

Jan 1, 1983

By Danqing Gao, Brijes Mishra

Spatial variance of rock properties is an important characteristic of rock which addresses the heterogeneity of mechanical and physical properties and their effect on underground mining. Assessing spatial variance can be useful for both locating potential difficult grounds and performing reliability analysis in the mining support system. This study shows a microscale numerical model for rock material based on continuum mechanics. To consider the spatial correlation factor of mechanical properties in realistic rock mass, this study introduces a spatial correlation concept into the traditional type III extreme value distribution model. Based on the improved microscale random model, we conducted a series of numerical uniaxial compressive tests and one longwall mine model to investigate the progressive failure of rock. The results show that spatial correlation factor can significantly affect the load-deformation curves and fracture patterns. The spatial variance model was applied to a longwall mine that included several cutting sequences to observe the influence of the spatial variance on roof behavior. The cohesion and friction random fields induced failure that propagated randomly through the immediate roof in different entries. The results showed that the spatial variance provides an accurate prediction of erratic roof falls in coal mines.

Jul 20, 2020

By J. Dubbert, T. H. Jones

"This paper describes a rib-control methodology that uses standing support to provide most of the lateral resistance to the rib. The method is analyzed, and its boundary conditions for rib control are described. In this method, an animal-fencing mesh product covers 80 percent of the rib surface and is sparsely bolted to the rib. Can supports or other similar stiff supports are installed primarily as roof support for the entry. As the rib spalls and dilates, the mesh catches the material and expands, pressing against the standing support. Mining proceeds, and vertical roof loads increase the normal force on the Can supports, causing friction at the top and bottom of the support to go up, thereby improving lateral resistance to rib swelling.At one mine in the western United States, this method has proved excellent at preventing the buildup of rib spall. It substantially reduces the number of bolts used for screen installation, improves installation efficiency, reduces manual labor and provides more rib coverage than many screening methods. Because standing support is typically part of the roof-control plan in longwall tailgates, no additional standing-support costs are incurred. IntroductionRib safety in underground coal mines is an oft-studied topic because ribs are high-hazard areas. An overview of early rib safety research can be found in Jones and Mohammed (2014). There is a significant difference between rib support and rib control. Support improves safety through the installation of strengthening elements, such as bolts and dowels, designed to reduce rib spalling. Although spall reduction is preferred, controlling how the rib fails is enough to ensure safety in some situations. Rib control uses external elements to provide confinement, thereby holding sloughed material in place, or to prevent falling rib material from striking mine personnel. This paper presents a study of a control method used on the pillar side of a longwall coal mine tailgate in the western United States."

Jan 1, 2015

By L. J. Buchanan

The relationship between hydrothermal ore deposits and hot spring systems has received intensive study in recent years, particularly as a consequence of interest in the energy potential of geothermal systems. Base and precious metal deposition in surface pools and at shallow depths in modern geothermal systems has been recorded in numerous publications (1, 2, 3) Theoretical studies of hydrothermal fluid flow at depth, connected to surficial hot springs systems, have been presented by White and others (1), Cathles (2) , Henley and McNabb (3). As a result of these and additional studies, numerous hydrothermal ore deposits are thought to have originated as genetic parts of larger geothermal systems. In particular, it appears that metal precipitation is greatly enhanced in zones of boiling where volatiles and steam are escaping (4). High grade, near surface concentrations of base and precious metals, deposited as a result of partial vaporization of rising fluids, are such a common aspect of modern not spring systems that ore deposition models are becoming based on what may be called a geothermal model. In its most general terms, this model requires an anomalously high thermal gradient which acts as the driving force behind a convecting hydrothermal system. The water may be entirely meteoric or may be In part at least of other origins. The water migrates towards the higher temperature area, becomes heated, and picks up alkalies and metals by dissolving minerals along the fluid path. As water exits to the surface above the heat source, a mass balance requires the incoming hot water to rise to replace the lost water. As the water rises past the elevation where the hydrostatic pressure is insufficient to prevent boiling, then boiling will occur. Depending on the salinity and the temperature of the water, boiling can occur anywhere from great depths to near surface. Boiling results in a loss of volatiles, a pH rise in the fluid phase, cooling of the remaining fluid, a rise in oxygen fugacity, a concentration of salts in the remaining liquid, and precipitation of ore and gangue minerals.

Jan 1, 1980

By Perry N. Halstead

The primary objective of the structural geology portion of the Kennecott Copper Corporation-U. S. Bureau of Mines Pit Slope Stability Study was to determine the attitude, geometry, and spatial distribution of geologic structures of the west wall of the Kimbley Pit for use in designing a maximum stable slope for the pit. A corollary objective was to develop and refine techniques for collecting and analyzing geologic structural data with emphasis on numerical methods that could be integrated with other aspects of pit design. Surface mapping techniques used were a modification of conventional joint set mapping and a detailed linear sampling method. For subsurface investigations both oriented core and a borehole camera were used. It was determined that the major faults in the area were favorably oriented for mining a steep stable slope. The jointing or natural fracturing, although complex, was not random in attitude and consisted of several persistent fracture sets and a number of secondary sets. The attitude of the persistent fracture sets was favorable for steeper slope angles, and these attitudes were used in the design considerations. There was no significant difference between the attitude of the fracture sets determined from the former and new slope face.

Jan 1, 1968

By John Barakso

The Sam Goosly or Equity silver deposit is fundamental- ly a discovery based on the analysis and interpretation of reconnaissance geochemical samples. The discovery was made by Kennco in an area of heavy forestation and wide- spread cover by thin glacial debris. No major mines had been discovered in the vicinity of the discovery prior to the geochemical reconnaissance, and the interpretation of the geochemical results therefore was based on data available through geologic mapping and the sample collection process. In the period 1959-1961, PE. Hirst and his crew, in 1962- 1965 P.T. Blackand his crew, and in 1966-1967 C.S. Ney and P.T. Black and their crew collected geochemical samples from the area of what is now the ore body. Several of these samples were compiled and reanalyzed in the winter of 1966- 1967 for various trace elements, including fluorine. A strong, almost 16-sq-km (10-sq-mile) fluorine anomaly was projected along with a very weak heavy metal anomaly. On the basis of this anomaly, a chalcopyrite-bearing quartz monzonite was discovered in 1967. This was a misleading, noneconomic discovery not associated with the Sam Goosly discovery. The interpretation of the geochemical data by Barakso that summer indicated that another source was responsible for the fluorine anomaly. The conclusion was based on the assemblage of trace elements. Therefore C.S. Ney recommended further regional soil sampling to check the original data. The early results of this follow-up sampling found over 33 ppm silver. First float, then ore outcrop was found in the area of the silver anomaly. The attached reprints complete the development of the property after the discovery of the outcrop of ore.

Jan 1, 1990

By P. Moran

A promising and increasingly popular tailings management strategy is to place cemented tailings underground as backfill. The placement of cemented tailings results in enhanced geotechnical stability and a purportedly more geochemically stable tailings form with lower leaching potential. Conventional subaerial tailings management can negatively affect water quality if weathering causes acid rock drainage and metal leaching (ARD/ML) to occur, whereas cemented tailings can limit leaching via porosity and permeability reductions and contribute alkalinity to limit the potential for ARD/ML. Cemented tailings backfill appears to be better, but how can this advantage be proven? Currently, cemented tailings backfill is utilized at mining operations internationally, but there is limited guidance on performing geochemical characterization and associated evaluation of the potential impacts to water quality. As a result, various approaches to simulating the leaching behavior of cemented backfill have been utilized, including some methods that are unlikely to represent weathering under site-relevant conditions. American Society for Testing and Materials (ASTM) Standard Test Method C1308-08 is a diffusion testing method initially developed to assess constituent release rates from solid nuclear waste forms. ASTM C1308-08 uses intact cylinders that more closely represent actual backfill than methods that require crushing or size reduction. It is widely believed that leaching from actual cemented tailings is controlled by diffusion through small pores that exhibit limited exposed surface area, making diffusion testing particularly applicable to cemented tailings placement.

Feb 27, 2013

By R. Washnock, P. James

"INTRODUCTION Abstract Tankhouse iron control through application of new treatment technology to mitigate conventional bleeding losses is considered. Implementation is discussed and the treatment economics explored. A representative case is assessed. Treatment benefits and application drivers for specific scenarios are noted. Background Hydrometallurgical ore processing has become a significant metal extraction/production avenue in recent decades. In copper mining; the focus for this examination, around 25% of global primary copper production and nearly 50% of US production result from various hydrothermal leaching extraction approaches coupled to Solvent Extraction/Electrowinning (SX/EW) metal production. Generally such processing is favored over pyrometallurgical processes for lower ore grades and as such is finding growing use and is expected to remain a key processing route looking forward with average world-wide ore grades falling as known ore reserves become exhausted. Target Problem And Motivation In hydrometallurgical processing the production circuit may be thought of as a chain of interlocked recirculation loops (Figure 1). Leaching dissolves the target metal from the ore along with other ore components which contaminate the Pregnant Leach Solution (PLS). Iron is a common component in copper ores and, as a result, occurs fairly ubiquitously in copper Pregnant Leach Solutions (PLS) generated by leaching. Leached components migrate through the production circuit from left to right (Figure 1) through a net combination of chemical and mechanical transport mechanisms. Selectivity at the recirculation loop interfaces tends to retard rejected component migration through the production process. As a result, overall relative contaminant migration fluxes are slower than the target metal (copper) and the contaminants tend to build up relative to copper in the more upstream portions of the processing circuit over time with iron often being a significant contaminant. Further, while copper is continuously removed from the system in appreciable amounts, little contaminant exit occurs and the absolute contaminant amounts and concentrations also increase throughout the EW circuit over time."

Jan 1, 2018