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By Moussa Wone

The Washington, DC Water and Sewer Authority (WASA) has implemented facility planning for the Anacostia River Projects portion of a program to bring its Combined Sewer System (CSO) into compliance with federal water quality regulations by 2025. The program includes approximately 19 kilometers (12 miles) of deep CSO storage/conveyance and flood relief soft ground tunnels, construction, vortex drop, overflow, maintenance and air release shafts, as well as near surface diversion structures and conveyances. The Project encompasses major technical and non-technical challenges including completion under a federal consent decree schedule, construction within the confines of heavily developed urban areas, difficult ground conditions, major infrastructure crossings, and close coordination with several major public agencies. This paper discusses the planning stage considerations related to the geotechnical investigation program, discusses obstructions that influenced alignment selection, and provides two examples of preliminary estimates of settlement induced ground movement due to the tunnel and shaft construction.

Jan 1, 2008

By A. Davis, C. Webb, J. Sorensen

The abandoned Belle Eldridge Mine near Deadwood, South Dakota, is on land controlled by the U.S. Bureau of Land Management (BLM). The mine produced lead and zinc during the first half of the 1900s. Because of acidic drainage and elevated levels of metals in tailings and waste rock, the site was evaluated in 1998 and 1999. After evaluation, the mine was remediated during 1999-2001 by the BLM. Since remediation, values of pH in water samples have been nearly neutral and specific conductance values have been much lower than before remediation. The Grizzly Gulch forest fire of July, 2002, consumed much of the Belle Eldridge site and resulted in greater than normal erosion and sediment flushing during the months following the wildfire. Had the site not been remediated and the tailings emplaced within a capped repository, generation of acidity and off-site migration of heavy metals within sediments could have been severe at downstream locations.

Jan 1, 2007

By W. A. Heitbrink, J. D. Ashley, R. E. Gresh, J. A. Organiscak, A. B. Cecala

Many different types of mobile equipment used in surface coal mining utilize enclosed cabs to protect equipment operators. The overburden removal process is extremely dusty and can cause excessive exposure to respirable dust, especially crystalline silica. After equipment is used for years, many components of the enclosure deteriorate and its effectiveness is greatly reduced. This report discusses a cooperative research study performed on an Ingersoll Rand DM45E surface drill, retrofitted with a new Sigma pressurization and filtration system. Respirable dust concentrations were substantially reduced from 0.64 mg/m3 during pre-testing to 0.05 mg/m3 during post-testing with the new system, representing a 92% reduction in dust levels in the drill cab. This new system appears to be a very well-built and sturdy device, well-suited for the mining industry.

Jan 1, 2002

By J. D. Miller

Characterization of feed material with respect to expected concentrate grade and recovery is fundamental to the design of improved separation efficiencies and to achieve sustainable development in the utilization of our mineral resources. An important reference point for this characterization is the liberation-limited grade/recovery curve which represents the perfect separation, the best separation which can be achieved for a given feed material limited only by the extent of liberation. Now, liberation-limited grade/recovery curves can be determined based on 3D mineral liberation analysis of feed material. Thus, actual separation efficiencies can be compared to what might be expected for a perfect separation limited only by the extent of liberation. It is shown that 3D mineral liberation analysis based on X-ray micro CT (XMCT) is preferred to 2D section analysis which overestimates the extent of liberation. By way of example, procedures and experimental results are presented and discussed for feed material in the case of phosphate rock flotation.

Jan 1, 2009

By R. Todd Swinderman

"Higher production demands across all bulk handling segments require increased efficiency at the lowest cost of operation, in the safest and most effective manner possible. As conveyor systems become wider, faster and longer, more energy output and more controlled throughput will be needed. Add an increasingly stringent regulatory environment and cost-conscious plant managers must closely review which new equipment and design options align with their long-term goals for the best return on investment (ROI).There are primarily two separate market segments using conveyor belts. One is in process industries such as food, chemicals, paper and powders. Handled in relatively low volumes, the bulk materials that enter these processes are generally of a consistent size and quality. The other market includes mining, coal handling and cement, where the bulk material’s quality and size vary, and the volumes are typically much greater. While both segments face similar issues with safety and environmental control, the properties of the materials handled and the volumes transferred suggest different approaches, with one thing in common: increased belt speeds requiring modern equipment upgrades.Safety at higher belt speedsWith companies recognizing that safety does indeed pay, safety is likely to become a new source of cost reduction. The percentage of mines and processing facilities with a robust safety culture are likely to increase over the next 30 years to the point where it is the norm, not the exception. In most cases, with only a marginal adjustment to the belt speed, operators quickly discover unanticipated problems in existing equipment and workplace safety. These problems are commonly indicated by the larger volume of spillage, increased dust emissions, belt misalignment and more frequent equipment wear or failures."

Jan 7, 2017

By Xiaodong Ma, Marek Pawlik

Introduction Guar gum is a natural nonionic polysaccharide. Guaran, the functional polysaccharide in guar gum is a chain of (1?4)-linked ß-D-mannopyranose units with a-D-galactopyranose units connected to the mannose backbone through (1?6) glycosidic linkages. The poly-mannose chain is randomly substituted with galactose units at a mannose-to-galactose ratio of 1.8-1.0 [1]. Cheng et al. reported that the molecular weight of natural guar gum is 1.935 • 106 [2]. Robinson et al. found that the molecular weights of five grades of commercial guar gums ranged from 4.4 • 105 to 16.5 • 105 [3]. Guar gum is frequently used as a depressant of naturally hydrophobic gangue minerals (e.g. talc) in the flotation of PGM-bearing ores, and according to Harris et al. a wide variety of modified guar gums are available for this application [4]. The Canadian potash industry utilizes natural guar gum as a blinder of water-insoluble slimes in the flotation of potash (sylvinite) ores, a process that is carried out in a saturated KCl/NaCl brine. The role of the polysaccharide is to prevent a primary amine collector from adsorbing onto these unwanted fine minerals. Hydrophobic interactions between basal cleavage planes and the polymer appear to be involved in guar gum adsorption on talc [5,6]. Liu and Laskowski stressed the importance of metal impurities on mineral surfaces that can serve as the active sites for polysaccharide adsorption [7]. This postulate was consistent with the later observation that, in addition to hydrogen bonding, the adsorption of guar gum onto talc was strongly dependent on the surface concentration of magnesium sites [8,9]. In this case the adsorption process was visualized as metal-polysaccharide complexation facilitated by the cis-configuration of the hydroxyl groups of mannose monomers. Hydrogen bonding and chemical interactions with metal sites were also suggested by Rath and Subramanian in their studies on guar gum adsorption on biotite mica [10]. In a recent study, Wang et al. demonstrated that hydrogen bonding is the main driving force behind guar gum adsorption onto talc [11]. Their data also show that the adsorption density of guar gum on alumina is about five times lower than the adsorption density on talc. Pawlik and Laskowski reported that the amount of guar gum adsorbed on illite was independent of ionic strength over a wide range of salt concentrations [12]. The adsorption density of the polysaccharide on illite did not measurably change with ionic strength from that of distilled water to about 50%-saturated KCl/NaCl potash brine (~3N KCl/NaCl). However, guar gum adsorption on dolomite dramatically decreased over the same range of ionic strengths, and no reliable explanation of that phenomenon was proposed [12]. The water structure-breaking or structure-making capabilities of background ions are usually ignored when discussing adsorption mechanisms of polymers. The concept of “structure breakers” and “structure makers” was first introduced by Gurney, and Frank and Wen who postulated that each ion is surrounded by three distinct regions of water structure [13,14]. In the first layer, water molecules are tightly bound to the ion. The second region extends farther away from the ion and is referred to as the region of structure breaking. Only at larger distances, where the ionic field is weak, water molecules form the “normal” ice-like structure. It is also now recognized that the first layer can be further divided into the primary and secondary hydration shells. Small, strongly hydrated ions reinforce the “normal” structure of water and the region of structure breaking disappears. In contrast, large less-hydrated ions disturb the ice-like structure and generate an extensive region of structure breaking. Experimentally, these two effects can readily be distinguished through viscosity measurements. Increasing concentrations of structure-breaking ions result in a decrease of the viscosity of aqueous solutions. On the other hand, increasing amounts of structure-makers significantly reduce the viscosity of water. Alkali metal cations form a sequence known as the Hofmeister series. The Hofmeister series - Cs+, K+, Na+, Li+ - orders the cations from the least hydrated to the most hydrated. Based on literature viscosity data for aqueous

Jan 1, 2005

By Jeffrey Mitsopoulos

King County?s (KC) Brightwater Conveyance Project in Seattle, Washington involves the construction of approximately 21 kilometers (13 miles) of bored tunnel, in three contracts, with four TBM?s which produce large amounts of real-time digital mining data. To facilitate the management of TBM data with a single interface and assist in project Quality Assurance, KC?s Construction Manager (Jacobs Engineering) recommended the use of the software TPC (Tunneling Process Control), developed by Babendererde Engineers GmbH. The paper demonstrates how TPC was used for oversight, analysis and QA on a complex tunneling project and how contemporaneous review and management of data results in a better understanding of TBM performance than can be obtained by retrospective analysis of data.

Arsenic (As) removal behavior from Changgoon mine tailings was investigated using Acidithiobacillus ferrooxidans (A. ferrooxidans) in well-controlled batch reactors by varying pulp density (0.5?4%, pH=1.8, temp=30oC), reaction initial pH (1.8?2.2, pulp density=0.5%, temp=30oC), and temperature (25?35oC, pulp density=0.5%, pH=1.8). The initial concentration of As in the mine tailings used for bioleaching tests was about 30000 ppm, and the size range of tailings used in this study was 63?74 µm. The reaction speed and initial cell concentration were fixed to 150 rpm and 107 cells/mL, respectively. To complement leaching experiments, pH, oxidation/reduction potential (ORP), and amount of ferrous/ferric ions in leachate were analyzed. Scanning electron microscopy and x-ray diffraction analyses were also conducted for the samples before and after leaching to see if any morphological and compositional changes in tailings took place during leaching process. The As leaching efficiency increased with decreasing pulp density, decreasing pH, and increasing temperature in the presence of A. ferrooxidans. Specifically, no significant change in As removal rate was observed when pulp density d 2% while the removal rate dramatically decreased at pulp density of 4%. Regarding pH effect, As removal rate was much more enhanced at lower pHs (i.e., 1.8 and 2.0) compared to pH 2.2. Increasing temperature was observed to tend to enhance As removal rate, showing about 20% enhanced leaching rate under 35oC compared to 25oC and 30oC at the elapsed time of 5 days. The results for As removal behavior at different conditions (i.e., pH, temperature, pulp density) were consistent with the change in pH, ORP, and ferric ion concentration in leachate, showing greater removal rate at the condition with lower pH, and higher ORP and ferric ion concentration in leachate. Furthermore, decreasing removal efficiency was likely in part due to the extent of the formation of by-product (i.e., jarosite) of ferric ions.

Feb 27, 2013

By A. Bascetin

Waste materials caused by mining activities are an important environmental problem. Paste technology is a good alternative for waste management because it has many benefits in the aspects of environment, cost and safety. Disposal of process wastes in paste form is an attractive option for waste management, as it eliminates or reduces the risks associated with conventional methods. Due to the geotechnical characteristics of the paste, it is very similar to soil materials. So determining the geotechnical properties of the paste material is essential to durability of the paste. The some important geotechnical properties are compressive strength, porosity, shear strength, hydraulic conductivity, water content, consolidation, etc. In this study, the important parameters and the relation between them were investigated and obtained some results which will affect for optimum design of waste management.

Jan 1, 2012

By S. M. Pickering

Banks frequently manage large privately owned mineral land trust accounts for estate heirs. The bank has a fiduciary obligation to follow the “Prudent Man Rule”, which requires that trust properties be managed at least as well as a prudent and knowledgeable owner could. However, banks may not have internal staff proficient at mineral property values, lease contracts, royalties, mining practices, etc. This is an opportunity for experienced geologic consultants and certified minerals appraisers to provide needed help. Items valuable to Trust managers may include: 1. Marketing privately owned mineral trust lands to mining or oil & gas firms, assuring competitive offering prices and terms; 2. Negotiating favorable new mineral lease and purchase-option contracts; 3. Monitoring progress of mining, royalty payments, land reclamation, and environmental clean-up work; 4. Balancing future mining income with later industrial, commercial or housing development, timber harvest, etc.; 5. Assuring that Depletion Allowance tax advantage is taken for actual mine royalty payments, but not for annual non-mining lease (rental) income; 6. Appraising in-ground mineral value for bank audits, estate tax valuations, and equitable property division between heirs; and 7. Serving as expert witness, representing the legal interests of the bank, trusts, and the mineral heirs in litigation. Banks do welcome reliable advice which assists them in achieving the “Prudent Man Rule” and improving mineral income to their land Trust accounts.

Jan 1, 2002

By J. A. Barsin

Stationary air pollutant sources established prior to the New Source Performance Standard (NSPS) are not, at present, subject to federal emissions regulations. However, proposed legislation could require many existing stationary sources to reduce emissions. This paper will report upon the laboratory work undertaken to date by B&W to commercialize a limestone system for sulfur capture both in pulverized coal and cyclone coal-fired utility boilers. Updates will be provided on the US EPA/State of Ohio/Ohio Edison/B&W sponsored pulverized coal full-scale limestone injection demonstration, and on the EPRI/Baltimore Gas 8 Electric, Atlantic Electric/B&W sponsored laboratory-scale cyclone coal limestone injection investigations.

Jan 1, 1986

Ceremonies for the induction of five mining industry pioneers into the National Mining Hall of Fame are scheduled for Saturday, Sept. 25, 2004 at the Las Vegas Hilton in Las Vegas, NV. The 17th Annual Mining Hall of Fame Induction banquet will begin with a reception at 6 p.m., followed by the dinner and program at 7 p.m. The five inductees are Georgius Agricola, David William Brunton, Herbert E. Goodman, David Ray Mitchell and Robert Peele. Georgius Agricola (1494-1555) wrote De ReMetallica, an original and valuable work that discussed everything known about mining during the first half of the 16th century. In De Re Metallica, Agricola reviewed practical means of finding ores, methods of surveying and mining, the assaying of ores, types and uses of mining machinery, smelting, mine administration and more. David William Brunton (1849-1927) is best know

Jan 1, 2004

By Taghi Sherizadeh, Kutay E. Karadeniz, Dogukan Guner, Samuel Nowak

Underground mining environments bring occupational health and safety issues with some severe dangers such as mine disasters like explosions. During such events, miners might escape using main access openings, or find a safe haven like refuge alternatives (RAs) to wait and be rescued and evacuated to the surface. In this paper, RAs are explained with their early and current applications. A classification as permanent and portable is explained depending on the conditions and their abilities. This classification is followed by the utilization and survivability of RAs with the requirements and recommendations of the main mining countries. Based on the utilization and survivability constraints, basic human requirements, waiting for a rescue team, and the required physical specifications of RAs during the events are analyzed in detail for various countries with their regulations. Among these, the specification, resistance to the explosion, is discussed in particular, and the studies in the literature are examined in terms of structural deformation. The highest deformed zones, the beneficiation of reinforcing steel components such as stiffeners, and the simulation approaches are investigated through this review.

Sep 24, 2022

By Marina Carreiro-Silva, Cátia Cardoso, Bruce Shillito, Lisa Mevenkamp, Alastair Brown, Maria J. Bebianno, Juliette Ravaux, Inês Martins, Nélia C. Mestre, S. Sousa Vânia

Mineral extraction activities in the deep sea will expose the local fauna to potentially toxic compounds. However, very few data are currently available on the complex ecotoxicological risks to deep-sea fauna from the potential release of heavy metals, trace metals and Rare Earth Elements (REEs). Nonetheless, this is key information essential to support the regulation of industrial activities in the deep sea. One of the fundamental issues that the MIDAS project will address consists in exploring the concept of whether the existing toxicity test protocols and limits established in shallow-water species are applicable to deep-sea mining. We will detail the specific challenges to recommending exposure limits within the deep sea and show preliminary results of comparative toxicity tests in the shallow-water and in the deep-sea environment.

Sep 1, 2014

By John McDonald, Peter C. Raleigh, Christopher Dishlip

This paper will discuss how the construction management team and the contractor working together on the City of Los Angeles, North East Interceptor Sewer project, managed information on a daily basis. Data was synthesized from various sources including: inspection, survey, instrumentation, laboratory and the tunnel boring machine data logger systems to produce state-of-the-art reports and graphics which will become industry standard. Special emphasis is placed on how the data is managed and interpreted in a clear and objective manner, permitting the tunneling processes to be carefully monitored and suggesting appropriate action to be taken by the construction management team and contractor.

Jan 1, 2005

By Jeff Ardron

Unlike the first predicted deep-sea mining (DSM) boom 35 years, the public response to the re-emergent possibility of DSM is this time round is not entirely optimistic, with serious economic, social, and environmental concerns being voiced. In the intervening years, the troubling notion of the ‘resource curse’ has been popularized, whereby the economies of developing nations rich in natural resources (agriculture, minerals, and fuels), paradoxically appear to fare more poorly than their brethren who have fewer such resources. There have been a variety of explanations and counter-arguments regarding why the resource curse occurs, including how it can be ‘escaped’, and even some disagreement on whether it in fact does occur. Nevertheless, many commentators appear to agree that that the quality of governance is strongly implicated in the socioeconomic success, or failure, of these resource-dependent nations, and could indeed be the deciding factor. Unlike nations with diversified economies, the majority of the income from natural resource economies, in the form of royalties and rents, flows through national government; hence, good governance and fiscal management is of particular concern.

Sep 1, 2014

The authors summarise the development and recent advances in the reconstruction and visualisation of three-dimensional objects from point data and describe applications to the reconstruction of orebody shapes from drill-hole and other data. In particular, Dijkstra's algorithm is proposed and implemented as a means of optimal reconstruction of complex orebody and topographical shapes from irregularly located sample data. The surfaces of the shapes are constructed from triangular tiles and the algorithms proposed by the authors are guaranteed to find the optimal set of tiles that "best" construct the surfaces on the basis of specified objective criteria. The algorithms are illustrated by applications to a complex silver/gold/zinc/lead deposit.

Jan 1, 2002

By N. Ward

The Gualcamayo Mine is located in the Andes Mountains north of San Juan, Argentina (Figure 1). A property of Yamana Gold Inc, it declared commercial production in July 2009 and has a total mineral reserve and resource base of approximately 88,000 kg of gold. Crushing operations for the open-pit mine are located in a 13,500 m3 underground cavern with a ceiling height of 22 m. More than 3,600 m of tunnels are used to access the cavern and convey the ore. The Project as described in this paper relates to the design and construction of the Main Cavern, Conveyor System Exit Tunnel, the Mechanical System Access Tunnels, and two 4.20 m diameter shafts (Ore Pass #1 and Ore Pass #2) as shown in Figure 2. [ ] Preliminary engineering for the Project was performed by Hatch Chile. Rizzo Associates Argentina, S.A., a division of Paul C. Rizzo Associates, Inc (Rizzo) was contracted to provide geomechanical and geotechnical support for the construction of the access tunnel system and geomechanical design and construction supervision for the cavern and shafts.

Jan 1, 2011

By John Trefny

Although mining is currently one of the smallest academic units on the Colorado School of Mines(CSM) campus, it is alive and well, with nearly 100 undergraduate and graduate students. For many years, Mines has had undergraduate and graduate programs in hard-rock mining. The school has recently transferred its physical mineral processing activities to the Mining Department. The program has also expanded to include tunneling, underground construction and industrial minerals. There are current discussions about increased research activities on cement and other construction materials. The Mining Department also teaches its share of what is called the “distributed core” courses with curricular requirements common to related programs, as well as mining safety and health, in conjunction with our continuing education department.

Jan 1, 2002

By S. E. Chetlin

In the mid-1970?s, the market value of tangible assets of S&P 500 companies far outstripped the value of intangible assets, including intellectual property (e.g., 83% tangible assets v. 17% intangible assets).1 By 2005, the picture was quite different. By that time and continuing to 2010, S&P 500 companies? market value of intangibles was about 80%, with tangible assets accounting for only 16% of market value.2 This swing highlights the importance in today?s world of understanding intellectual property rights and varying strategies and options for protecting them. This paper discusses intellectual property rights particularly patents and trade secrets, specifically: 1) types of intellectual property; 2) choosing the mode of intellectual property protection; 3) obtaining patent protection; and 4) using patents as a sword versus a shield.

Jan 1, 2012