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By J. W. Hawkins, K. B. C. Brady, K. Miller, J. Cuddeback

Remining of abandoned coal mines in Pennsylvania requires the implementation of pollution abatement and mining techniques called Best Management Practices (BMPs). Water-quality data from over 100 remining sites with more than 230 abandoned discharges were analyzed with respect to the types of BMPs employed to abate the pollution loadings of acidity, iron, manganese, aluminum and sulfate. Discharges exhibiting a significant decrease in acidity were most highly associated with sites where large volumes of alkaline materials were encountered (66.7%) or added (63.7%). The best results for iron loading were achieved with large-quantity alkaline addition (54.6%) and water handling systems (47.8%). Water handling systems (47.4%), daylighting (40.7%), and revegetation (40.2%) were associated with significantly lower manganese loadings. The decreases in acidity and sulfate loads associated with increasing the amount of alkaline material in the backfill indicates that the production of acid mine drainage can be retarded by adding large quantities of alkaline materials.

Jan 1, 2002

By R. Oler

The mining industry?s traditional preference for protective coatings in corrosive environments, due to cost considerations, has been to apply galvanized and epoxy coatings. As a result of extreme pH levels and the limitations of current products, a new coating has been developed to withstand severe conditions. Harsh chemicals and corrosive groundwater pose added challenges to mines in maintaining long term ground support which demands continuous rehabilitation. This paper highlights the challenges and identifies a solution by applying a new economic coating to DSI?s Omega Bolt? that withstands the most corrosive of conditions. [ ]

Jan 1, 2012

By D. McSwain-Santos

Soda ash is the trade name for sodium carbonate, a chemical refined from the mineral trona or naturally occurring sodium carbonate-bearing brines (both referred to as natural soda ash) or manufactured from one of several chemical processes (referred to as synthetic soda ash). It is an essential raw material in glass, chemicals, detergents and other important industrial products. Production U.S. soda ash production during 2004 increased to10.9 million Mt (12 million st). Five companies comprised the domestic soda ash industry. Four were in Wyoming operating five plants. One was in California with one plant.

Jan 1, 2005

By A. Halim, A. Martikainen, S. GYAMFI

This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine from 2018-2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes to ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 2.0 Mtpa.

Sep 30, 2021

By G. P. White, J. M. Jones

Computer simtiation is a technique that has beers around for many years. Its applications include designing steel mills, planning space shota, or even developing ways to beat the casinos in Las Vegas. However, the use of computer sirndation in surface coal mining is fairly recent. To promote its use, several government agencies, including the US Bureau of Mines, Forest Service, and Department of Energy, contracted with universities and private companies to develop computer simulation programs for surface coal mining. Some of these developers include McDonnell-Douglas Electronics Co., Pennsylvania State University, Montana State University, Fluor Mining and

Jan 9, 1984

By A. Redman

Aquatic organisms are sensitive to free cyanide (HCN) though the presence of certain metals that can form stable complexes and thereby reducing both the amount of bioavailable cyanide. Recent work has suggested that consideration of HCN rather than total cyanide can provide the basis for water quality criteria. Cyanide is often present in complex effluents that affect speciation and bioavailability. We have developed a model to predict the speciation of cyanide in complex effluents and have shown that this model can predict the toxicity of metal-cyanide complexes in terms of HCN. This study evaluated available cyanide toxicity exposures with this model to assess the role of water chemistry (e.g., metal-cyanide interactions) on the observed. Toxicity endpoints based on total cyanide ranged over several orders of magnitude for a variety of metal-cyanide mixtures. However, predicted HCN concentrations among these same tests described the observed toxicity data to within a factor of 2. Aquatic toxicity can be well described using HCN though in certain metal-cyanide mixtures toxicity was jointly described by HCN and elevated levels of bioavailable metals. This work was performed in support of an industry-sponsored reassessment (Gensemer et al 2006) of the U.S. EPA water quality criteria for cyanide (EPA 1985) using free cyanide as the basis for the re-calculation. The work presented in this manuscript presents technical support for using free cyanide as the preferred basis for this recalculation.

Jan 1, 2011

By H. Hamza

Oil sand tailings are disposed of in large ponds in which MFT (Mature Fine Tailings, a stable suspension of fine particles in water) forms after many years of settling. Long-term storage of large volumes of MFT is costly to maintain and also poses an environmental liability. The Advanced Separation Technologies laboratory at CANMET Western Research Centre has worked closely with oil sand companies to eliminate MFT generation by applying paste technology to oil sand tailings. In this process the fine tailings are flocculated to produce a thickened material that has the potential to consolidate to a dry landscape, while warm water is recovered and recycled for reuse in the extraction process. This paper presents some results of an extensive technical program involving bench-scale tests for flocculant selection and continuous thickener pilot tests.

Jan 1, 2002

By Maryam Motamed, Jeremy Stone, Leigh Anne Zhang

Controlling and predicting ground movements are essential to the design of shoring systems. The Courthouse Commons tunnel in San Diego, California, included a 56-foot-deep temporary shaft as a launching point for tunneling using the Sequential Excavation Method (SEM). The rectangular shaft was unique in that it was surcharged on one wall by an 11-story building and employed a hybrid support of excavation design. An array of geotechnical instrumentation was used to monitor lateral and vertical movements at the ground surface. This paper compares the measured ground movement with the predicted ground movement from various excavation stages

Dec 1, 2022

By J. C. Fox, V. L. Ketellapper

The Summitville Mine, located in the mountains of Southwest Colorado, is an abandoned gold mine. From 1984 to 1992, Summitville was mined for gold using an open pit heap leaching technology. During this period, the volume of acid mine drainage released from the mine significantly increased. This was attributed to the development of the mine pits, the waste rock piles, the heap leach pad, and increased discharges from the drainage adit. The release of this acid mine drainage resulted in the destruction of the aquatic ecosystem for more than twenty miles downstream of the mine. Beginning in 1993, plans were implemented to reduce the amount of acid mine drainage released from the mine. The majority of this work has been completed at the mine. This work includes removal of the Cropsy Waste Pile, closure of the Heap Leach Pad, and revegetation of disturbed areas. Significant improvements to water quality downstream of the mine have occurred resulting from mine reclamation. Aquatic life has returned to portions of the previously mining impacted areas. This study discusses the actions taken to reduce the amount of acid mine drainage generated at the Summitville Mine, the costs of these actions and the resulting reduction in metal loadings. Over 250 samples taken at over 10 locations since 1993 form the basis of this evaluation. Copper loading is analyzed as an indicator of the effectiveness of the actions taken.

Jan 1, 2002

By Bahram Sameit

Blast engineers have been taking advantage of image-based rock fragmentation analysis methods for the past three decades to estimate rock size distributions. These methods utilize a range of image segmentation techniques, from manual to fully-automated, to delineate the edges of rocks in images. Rock delineation results are then converted to physical rock sizes (and percentage passing curves) by scaling the image pixels to correspond to physical measurements. The size scaling process is critical for acquiring physical measurements, but specifc to the limitations of different applications. This article starts by presenting a shovel bucket-based fragmentation analysis system, where scaling is done using the known width of the shovel bucket within the image. It will then describe methods that use pictures captured by digital cameras with scaling reference objects in the view. Finally, the article presents a method that uses three-dimensional imaging to capture images without the need for scaling reference objects.

By L. Hoffman, F. Seymour, S. Hoerger

Newmont has a large integrated operation in Northern Nevada with numerous mines, stockpiles, and processing facilities. There are over ninety defined metallurgical ore types and over sixty defined gold recovery process options. To take better advantage of the available synergies, a complete Nevada wide mine plan and process model along with a mixed Integer and Linear Programming optimization tool has been developed and implemented. This system is maintained and operated by a Nevada Planning Group. Standard in-house planning software tools and methods have been implemented at all mine sites. While increasing the effectiveness of planning in Nevada, these changes have allowed a significant reduction in overall Mine Engineering staff.

Jan 1, 1999

By Trevor R. Ellis

The extractive industries addition to the International Valuation Standards (IVS) is scheduled for publication in the next edition of the IVS book in January 2005. This will provide guidance for valuation of minerals and petroleum industry assets of all types for all appraisal uses. It will provide asset valuation support to the International Financial Reporting Standards for the stock markets of the world, and a global umbrella standard which can be supplemented for local needs by institutes and regulators. This paper discusses implementation of the IVS within the minerals industry and important issues that the industry should confront.

Jan 1, 2005

By A. J. Romeo

The Old Hickory heavy mineral ore body, which lies within the Fall Zone of south central Virginia, has been mined since 1997. There are many differences in this deposit when compared to humate-laden mineral sands mines of southern Georgia and Florida. These differences include an abundance of kaolin-rich clayey sands, highly concentrated and iron-colored heavy mineral sand units, and a base of mineralization that is undulating. For these reasons, the selective approach of dry mining with track excavators is ideal. Grade control in this deposit uses traditional panning techniques and requires an intimate working knowledge of near-by drilling data. Mine geologists train equipment operators to recognize the base of mineralization by such characteristics as a stark color change, significant changes in grain size, and/or considerable, recognizable shifts in the concentration of heavy minerals. The regular pattern of mine site drilling does not always prepare the geologist and digging crews for occurrences of near-vertical contacts between the saprolite basement and the ore sands. These deformed areas, combined with undulating and pinching ore zones, require close monitoring and flexibility by the geologist and the mine operators.

Jan 1, 2005

By X. M. Yuan

In the flotation of Zn-Pb ores, sphalerite is floated following copper sulfide activation. In this type of sulfide ore, pyrite is commonly treated as a gangue, and poor selectivity between sphalerite and pyrite/quartz is often reported. But pyrite may also appear in association with gold, and flotation of such auriferous sulfides is of great importance in many countries (e.g. South Africa, Australia). In the cationic flotation of sulfide ores with dodecyl amine, sphalerite can be floated while depressing quartz and pyrite. While in a well-aerated pulp in the presence of lime (especially after oxidation with H2O2) the cationic flotation of pyrite is depressed, oxidation of pyrite in the presence of Na2S makes it floatable with amines even in very alkaline environment.

Jan 1, 2002

By 1980, the U.S. mining community had reached a broad consensus regarding coal pillar design. The pillar load could be estimated from tributary area theory, and the pillar strength from empirical formulas and laboratory coal strength testing. Then the growth of longwall mining required new thinking. Recently, powerful design methods have emerged from analysis of large data bases of real-world pillar successes and failures. These include the Analysis of Retreat Mining Pillar Stability (ARMPS), the Analysis of Longwall Pillar Stability (ALPS), the Mark-Bieniawski rectangular pillar strength formula, and guidelines for preventing massive pillar collapses. Sophisticated numerical models have also helped transform the pillar design landscape. In the process, our understanding of pillar mechanics has been greatly enriched.

Jan 1, 1999

By R. O. Ifill

Alternating current electrocoagulation (AC/EC) may be an alternative to chemical coagulation in the thickening of tailings in the mineral, coal and petroleum industries. In the current study, ground silica (d50 as received, 20 µm) served as the model tailings solid with characteristically poor settling behavior. Its natural initial settling rate was 1.6 x 10-3 cm/min. This paper discusses the indirect application of AC/EC via aluminum electrodes to the enhancement of the settling behavior of the silica. ?Indirect AC/EC? means that the silica was coagulated upon dispersion in water that had been treated by AC/EC. The effect of AC/EC retention time on settling behavior is examined and the water chemistry is analyzed. Test results show that the initial settling rate of silica was enhanced by a factor of 4,000 at its maximum of 6.4 cm/min, under the conditions employed. Settling enhancement was achieved upon contact between the AC/EC-treated water and the silica, and the enhanced initial settling rate was dictated by the floc size. The aluminum dosage increased with AC/EC retention time, reaching a maximum concentration that was equivalent to 13.1% of that predicted by Faraday?s law. Complex aluminum ions are considered to have adsorbed onto the silica surface and an adsorption mass ratio of 0.3 mg Al/g silica was the most effective in enhancing settling behavior. Owing to pH change or slow kinetics, aluminum hydroxide precipitation did not lower the ion product ([Al3+][OH-]3) below the KSP of 6.3 x 10-32.

Jan 1, 2011

By ANGELA NAIR AVELAR, Reiner Neumann, PAULO R. G. BRANDÃO

Three types of apatite were identified by means of cathodoluminescence (CL) images in flotation concentrate and tailing samples from the Catalão Mine in Brazil. They are predominantly blue apatite, followed by green apatite and, less frequently, yellow apatite. The chemical compositions of these types of apatite were determined by electron microprobe analysis and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Blue and green apatite responded well to the process, thus remaining in the concentrate, while yellow apatite remained in the tailings. Yellow apatite has the lowest phosphorus pentoxide (P2O5 ) content and largest anionic and cationic sites substitution, followed by green apatite, whereas blue apatite is the most homogeneous, with highest phosphorus (P) and calcium (Ca) grades and lowest substitution level.

By G. Watson, S. Sawyer

A Method to Calculate Hydrodynamic Loads on Underground Bulkheads Bulkheads are structures built in openings in underground mines to impound water, preventing the water from entering the active mine workings. These structures not only have to be designed to withstand the static, hydraulic pressure, but also the dynamic or seismic pressure, which would be generated by an earthquake. Bulkheads can be considered underground dams. Unlike dams on the surface, bulkheads are often subjected to hydraulic heads that exceed the heights of the bulkheads. Theodor von Karman in 1933, and Westergaard earlier, developed the equation by which the hydrodynamic pressures on surface dams could be calculated. Civil engineering handbooks of today contain this equation. In this paper, using the methodology developed by von Karman and Westergaard, the authors have developed an equation by which the hydrodynamic forces on bulkheads could be calculated when the hydraulic head exceeds the height of the bulkhead.

Jan 1, 2007

By J. M. Barker, V. T. McLemore

Most discussions of sustainable development (SD) in mining relate to metal mines in rural areas. Industrial minerals (IM) are closer to urban areas primarily owing to a high transport-cost component of delivered cost. This visibility to large populations overshadows IMs relatively small operation size and generally lower waste volume and toxicity. The IM industry needs to rethink its way of doing business to fit into the SD paradigm. Society and business in general will also undergo significant change to enable industrial SD along the lines of triple-bottom-line accounting with government pushing everyone. The benefit to IM mining from embracing SD is a renewal in their social license to operate and a rebirth of mining as a positively-viewed force in society. This positive view would lead to lower acquisition costs because society would not fight so hard to eliminate nearby mining. This would ease the current exploration woes of the IM industry by opening up new deposits for exploration and more readily allowing placement of mines nearer to markets. The earlier in the exploration process SD is initiated, the better.

Jan 1, 2004

By S. Ilyas

Technical innovation in electrical and electronic equipment with new functions and design, stimulate consumer?s purchasing desire towards the latest equipments and this leads the rapid increase in the production of increased amount of waste materials Treason et al (2006) have reviewed the data on electronic waste generation in different parts of the world. Studies by Bertram et al (2002) have also affirmed that waste electrical and electronic components are the fastest growing waste category; this emphasizes the need for efficient recycling strategies. Recycling of electronic waste is an important subject not only from the point of waste treatment but also from the recovery aspect of valuable materials. However, recycling of electronic scrap is still quite limited due to the heterogeneity of the materials present in the products (Veit et al. 2005). A bioleaching based process offers a number of advantages compared to the conventional pyro or hydrometallurgical methods (Lee et al. 2007; Lee and Pandey, 2012). The advantages include simple, inexpensive (in some cases) and eco-friendly approach besides, generation of less active leach residue then other metallurgical processes. Though, biohydrometallurgical process has been successfully applied for the leaching of metals from ores (Olson et al. 2003; Rawling 2000), data pertaining to its application for the extraction of electronic scrap is still scanty. Recently, a few studies have been undertaken for extraction of metals from electronic scrap/printed circuit boards (Brandl et al. 2001; Faramarzi et al. 2004; Choi et al. 2004, Ilyas et al. 2007; Ilyas et al. 2010). These studies were conducted with mesophilic chemolithotrophic (Acidithiobacillus ferooxidans and Acidithiobacillus thiooxidans) or cyanogenic bacteria (Chromobacterium violaceum) or moderate thermophilic bacteria (Sulfobacillus thermosulfidooxidans). However, compared to bacterial leaching, fungal leaching has the following advantages: (i) ability to grow under higher pH, and thus is more suitable in bioleaching of alkaline solid waste (ii) a generally faster leaching process with shorter lag phase (iii) Chelation of excreted metabolites (e.g. organic acids) with metal ion, thus reduce its toxicity to the biomass (Burgstaller et al. 1993; Aung and Ting 2005). The specific objective of this work was to; ? Collection, isolation and enrichment of fungal strain ? Evaluate the abilities of Penicillium chrysogenum to leach metals from electronic scrap at various leaching modes (one-step bioleaching, two-step bioleaching, spent medium leaching, fresh medium leaching, leaching with deionised water and chemical leaching). ? Comparative study of all leaching modes

Feb 27, 2013