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THE FUTUREGEN CLEAN Coal project will be the recipient of $1 billion worth of federal stimulus money by way of the U.S. Department of Energy (DOE), which announced the commitment to the project. The money is expected to kick off years of further work that could finally see the project completed. One of the companies involved, Ameren Corp., said the $1.2 billion project ? which will include some private funding ? still has a number of hurdles to clear.

Jan 1, 2010

By David A. Heitman

The Buick Concentrator is a highly automated operation which utilizes a process control system for continuous monitoring and control. The process control system development, installation, and application to the concentrator grinding and flotation circuits are presented in this paper. The design and implementation of analog field sensing instrumentation, a continuous on-stream X-ray analyzer, grinding and classfication circuit controls, and a recent digital process control system utilizing a centralized computer are discussed. Emphasis is placed on the project planning and installation of the digital control system including a presentation of future plans for continuing application of computer control.

Jan 1, 1982

By H. G. Naidu, Raj K. Singhai, S. P. Singh

Introduction The economics of open-pit mining de¬pend heavily on the cost of overburden removal. It is necessary to maintain a pit slope as steep as possible. Steeper slopes lower the volume of overburden to be handled, thus lower the cost of material handling. There is, however, a limit to which the pit slopes in any given situation can be steepened. Steepening beyond this point could jeopardize the pitwall stability, ren¬dering it unsafe. It might even result in curtailment of pit production. Several factors affect the stability of pitwalls. Some are natural, such as topogra¬phy and regional and local geology. Others are man made, such as pit geometry, ground water management, equipment, drilling and blasting, and the type of excavation. Greater control can be exercised in the latter with proper planning and by following a set of procedures based on field experiences. This article deals with one such control¬lable factor - drilling and blasting. The eco¬nomics of steeper pit slopes is discussed, followed by a record of drilling and blasting practices in western Canadian surface mines. Microprocessor-based instrumentation and its application to blasthole drilling is also described. Economics of steeper pit slopes The economics of steeper pit slopes is not a new issue. It should be reinforced, though, that pit slopes must be as steep as possible to ensure maximum recovery of minerals at a minimum stripping ratio. For operating, economic, and safety reasons, different pit slopes are maintained during different phases of pit development. Figure 1 shows a hypothetical ore body, cylindrical shape, with a radius of 225 m (740 ft) and located 30 m (100 ft) beneath the surface. The mining operations are planned at two different slope angles of 25° and 40°. The ultimate pit depth was established on the basis of the criterion of "break even pit." The variation of the stripping ratio at differ¬ent mine levels is shown in Fig. 2. Table I summarizes the eco¬nomics involved for two pit slopes, 25° and 40°. Figure 3 presents the profits during the life of the mine for these two pit slopes. This study shows that steeper slopes for an open pit operation are far more advanta¬geous than flatter slopes. But, what is the optimum slope at any one point in the life of a moving pit? And how can the stable slopes be maintained over the short- and long-term? Canadian blasting practices A survey of blasting practices in western Canadian surface coal mines revealed that, at most mines, hard consolidated overburden is drilled and blasted. Blastholes are drilled with rotary crawler-¬mounted rigs using bits in the 220 to 310 mm-diam (8.5 to 12 in.-diam) range. Typi¬cal hole depths are 12 to 18 m (40 to 60 ft) to accommodate the pit bench heights of 12 to 15 m (40 to 50 ft). For a 12-m (40-ft) high bench, a typical hole will be 14.6 m (48 ft) deep including the subgrade drilling of 2.6 m (8.5 ft). Half of this hole will typically be a powder column and half will be stemmed. For a 15-m (50-ft) bench, a typical hole will be up to 18 m (66 ft) deep including the subgrade drilling. Drilling patterns are usually 9 m (29.5 ft) spacing and 9 m (29.5 ft) burden. De¬pending on local geology and hole diameter selected, drilling patterns of 8 x 8 m, 8.5 x 7.3 m, and staggered patterns of 11 x 5.5 m

Jan 1, 1989

Tables

Jan 1, 1973

By Egons R. Podnieks, Wallace W. Roepke

Mining technology to utilize vital lunar resources will be required for any commitment to permanent lunar basing. Lunar mining must be viewed both as a major supporting element for space resource commercialization and for creation of human settlements on lunar and planetary surfaces to support long-range space exploration. The Apollo missions to the lunar surface and results from fundamental research on analogue lunar rocks by the Bureau of Mines, and others, have provided the initial data for developing lunar mining technology. The multi-disciplinary research projected in this paper outlines the scientific and engineering needs to realize the lunar mining goals.

Jan 1, 1990

By Alex Stewart

Most iron bearing ores treated by the R=N Direct Reduction Process yield products lower in phosphorus than the initial ores. The sulfur is also removed and generally is in the range of 0.02 to 0.05 percent in the final R=N product, independent of the sulfur content of both the ore and carbon fuel used. The mechanism and thermodynamic justification of the principal reactions leading to the removal of both phosphorus and sulfur and the control of sulfur in the iron concentrate produced are discussed and supported by the results of laboratory experiments. In substantially all iron ores (containing up to 4% sulfur as sulfate) and solid carbon fuels (containing sulfur from 1 to 8%) tested, the rejection of sulfur has been in the order of 90-95%, with not more than 0.02 0.05% sulfur in the final metallic iron product. With respect to phosphorus-bearing iron ores ranging up to 0.70% P205, the rejection to tailings has been in the order of 70-95%, resulting in not more than 0.03 - 0.07% phosphorus in the final product.

Jan 1, 1958

By Jacob Mathis, Mark Bradford, Alston Noronha, R. M. True

In June 2022, Louisville MSD completed a 6.5-km (4.0-mi), 6.1-m (20-ft.) diameter CSO conveyance and storage tunnel system located along the Ohio River in downtown Louisville, Kentucky. For large diameter shaft and tunnel construction, drill-and-blast operations among other methodologies were used in close proximity to federal, commercial, and residential properties with no impact to stakeholder infrastructure. s one of the rst maor tunneling proects in Louisvilles metropolitan area, this paper explores Black & Veatchs rigorous geotechnical instrumentation monitoring program that provided uality assurance for local stakeholders and afrmed innovative tunneling solutions can be successfully executed in an urban setting.

Jun 23, 2024

By J. K. Horbaczewski

The reclamation of an open dragline pit (Pond A3P-2) at the Gibbons Creek lignite mine in east-central Texas required neutralization of acid mine pit water. At the start of treatment with hydrated lime (Ca(OH)2) on March 28, 2000, the pond had partially filled with 913,000 m3 (740 acre ft) of pH 4.9 water. Another 666,600 m3 (540 acre ft) of pH 3.3 water was pumped in from an adjacent pit (PitA3P- 1). By the end of the project (July 5, 2000), a combined volume of 1,579,000m3(1,280ac-ft or 417milliongal) in PondA3P-2 had been successfully treated to pH 8.2 with 431 t (475 st) of lime. This was two to three times more neutralizer than laboratory trials and detailed chemical titration had predicted. The main reasons for the difference are thought to be the inadequate representation in a laboratory setting of some of the chemical reactions that occurred in the field, including incomplete mixing of reactants, reactions with clay minerals in the pit walls, the kinetics of biologically-mediated reactions and the kinetics of aluminum oxyhydroxide polymerization (aging).

Jan 1, 2002

By R. N. Gow

Acidic treatment of enargite (Cu3AsS4) dissolves both arsenic and copper from the mineral and then attempts to separate them in the leach solution. The reactivity of enargite was examined in acidic solutions, over the pH range 1-7, to determine a potential range for co-dissolution.. Enargite mineral samples from Butte, MT and Quirivilca, Peru were used as working electrodes in a cyclic voltammetry corrosion cell setup, which were then cycled multiple times over -1000 to 1000 mV. Surface reactions and transitions were characterized using in-situ Raman spectroscopy, which were then compared to updated predominance diagrams for the copper-arsenic-sulfur system from a previous study done under alkaline conditions. The region of co-dissolution is limited to > 600 mV vs. SHE and pH < 1 under the proposed diagram.

Feb 23, 2014

By Shinzaburo Kato

In 1977 Kawasaki Steel Corporation (KSC) built No. 6 BF (Blast Furnace) with an inner volume of 4 500m3 as part of our program to produce 8.5 million tons of crude steel a year at Chiba Works. As the primary raw material to be used in No. 6 BF, we decided to use sintered ore, because we were confident in the obvious advantages of our technology developed by that time on sintering and BF operation using sintered ore. At Chiba Works, however, we had no space for the construction of a sinter plant, so we decided to build it abroad. Sintered ore is easily crushed and degradated. Producing sintered ore at a point far away from the blast furnace and transporting it across the ocean was the world&apos;s first attempt. To successfully realize it, we conducted a series of fundamental surveys and studies with special stress on the real aspects of degradation of sintered ore caused by long-distance transportation and handling and the ways and means to prevent the degradation. As a result, we decided to build a plant on the Mindanao of the Philippines.

Jan 1, 1982

By H. X. Li, A. Correa, M. M. Zhang, W. Xuan, M. Andrade

"With increasing demand for steel and depletion of high-grade iron ore deposits, more research efforts are being directed toward extending the life of existing ore reserves and developing technology to treat low-grade iron ore resources. Among all the reported technologies, biotechnologies in mineral processing – specifically bioleaching and microbially induced flotation – have emerged to be considered as low-cost, environmentally friendly potential alternatives to many of the current mineral processing techniques. This paper provides a comprehensive review of current research on the use of microorganisms for iron ore beneficiation and, further, discusses the applicability of bioleaching, bioflotation and bioflocculation for the beneficiation of low-grade iron ores.IntroductionIncreasing global demand for raw materials has led to diminishing resources of high-grade iron ore. As a result, the mining and utilization of low-grade hematite, limonite, specularite, siderite and goethite ores have attracted more and more attention. However, these types of iron ores are of complex paragenesis and fine disseminated grain size, and often contaminated by phosphorus in the form of solid solution. The distribution of phosphorus throughout the iron mineral crystals prevents the effective use of physical separation techniques, and these complex ores are at present largely untapped due to a lack of cost-effective and efficient processing methods. Chemical leaching and roasting-magnetic separation approaches have been mainly tested only on the laboratory scale and are all either cost prohibitive or ineffective when used on low-grade complex iron ores."

Jan 1, 2015

By John E. Caffrey

United States Steel Corporation began mining coal in southern West Virginia at the turn of the century, and until the late 40&apos;s production was confined to underground mines. Surface mining was initiated in our southern West Virginia -holdings as a means of recovering coal that could not be obtained by underground mining methods. After observing and evaluating surface mining methods employed by other companies, some of which operated on lands of U. S. Steel on a lease basis, we undertook the establishment of a surface mining operation. Our method, as, initiated in the early 50&apos;s, remains basically the same today. Variations have come about primarily by equipment modifications. The method consists&apos; of a pioneer cut to establish the coal outcrop, a drill bench for drilling, blasting, and removal of the overburden from the top of the coal. The land is rugged except for the flood plains of some of the larger streams. The mountains have steep slopes, averaging 30 degrees, with relatively sharp ridges and very narrow valleys,. Geologically, the coals_ lie in the Pocahontas formation of the Pottsville group in the Pennsylvanian system. This means that the coals in our area of operation lie at the base of. The coal measures in the Appalachian range. The coal that we have mined is primarily the Pocahontas nos. 3 and 4 seams. We have mined negligible amounts of other seams in the Pocahontas groups above the no. 4 seam. The Pocahontas no. 3 seam, which is the lowest mineable seam geologically in this area, lies anywhere from 700 feet below: the valley floor up to 400 feet above the floor. This is occasioned by the Anticlinal formation which gives us grades Of about 9% at the anticline, decreasing to about 1 to 1-1/2% on the extreme flanks. We have the opportunity to engage in surface mining where the coal seams intercept the surface above the valley floors.

Jan 1, 1972

By S. Natansohn

A prevalent technique for the recovery of silver from wastes generated in silver-tungsten electrical contact fabrication is electrowinning. Such scrap is placed in a permeable plastic basket which constitutes the anode compartment and this basket is suspended in a larger cell in which the cathode is mounted. A silver nitrate solution is used as the electrolyte and, upon application of an electric field, the silver migrates to the cathode where it deposits out. At times, there is tungsten migration to the cathode compartment and consequent co-deposition with the silver. This W contamination, which may amount to several thousand ppm, necessitates additional purification of the deposited Ag and its removal would therefore be advantageous. The elimination of the W impurity would also extend the operating period of the cell with corresponding increase in the Ag output and savings in labor costs.

Jan 1, 1982

By Viktor Tokle, C. W. Dawson

The Devico directional core drilling system and its capabilities are described, with reference to other directional drilling technologies and the advantages and disadvantages of these systems. The advantages and disadvantages of a number of borehole navigation systems are also presented. A discussion of the applications of the technology follows, illustrated by case histories. Finally, the environmental impacts and benefits of the technology, in comparison to more conventional systems, are presented.

Jan 1, 1999

By Denis Murphy, James Gusek, Carl Mann, Thomas Wilderman

An active underground lead mine produces water having a pH of 8.0 with 0.4 to 0.6 mg/L of Pb and 0.36 mg/L. of Zn. This water is pumped at the rate of 1.200 gpm into a five-cell, bioreactor system covering about 5 acres. The gravity flow system is composed of a settling basin followed by two anaerobic bioreactors arranged in parallel which discharge into a rock filter polishing cell that is followed by a final aeration polishing pond. The primary lead removal mechanism is sulfate reduction/sulfide precipitation. The discharge has met stringent in-stream water quality requirements since its commissioning in 19%. However, there have been startup and operational difficulties. The system was designed to last about 12 years, but estimates suggest a much longer life based on anticipated carbon consumption in the anaerobic cells.

Jan 1, 2000

By Dafydd Chandler, Milissa Hirst, Charles Hurst, Gary Snyder, Leszek Glodkowski

The Delaware County Regional Water Quality Control Authority (DELCORA) will be adding tunnel infrastructure to its wastewater conveyance system. This program involves the construction of a conveyance/storage tunnel and related facilities. The proposed 12- foot to 14-foot (±) finished diameter, TBM mined deep rock tunnel spans over 8.5 miles and lies approximately 80 ft-120 ft below the surface. The system is connected to the surface by at least five vertical online shafts and one offline shaft with associated 800ft long adit. This paper provides project details including data on the geologic conditions in which the tunnel will be constructed.

Dec 1, 2022

By S. P. Taite, A. R. Charest, P. D. Lewis

The El Sauzal deposit is a classic, high sulfidation, epithermal gold system located in southwestern Chihuahua State, Mexico. The prospect was discovered by a Francisco Gold Corp. geologist in1995. El Sauzal was encountered as a result of an extensive grass-root exploration program in the rugged, dissected volcanic terrains of the Sierra Madre Occidental, around the historical Batopilas Silver Camp. At El Sauzal, high grade gold is hosted within a series of more permeable, low-dipping, lithic and fine-grained dacitic rocks of early Tertiary age. The mineralization appears to be both structurally and lithologically controlled. The alteration characteristics are typical of a high sulfidation system including kaolinite, illite, alunite, dickite and pyrophyllite. The deposit’s gold distribution, as recorded from drill-hole data and surface samples, varies from 0.2 to 650.0 g/t. The estimated geological resource, as calculated from an independent study completed in 1998, was 3.0 million oz @ 2.03 g/t including a minable reserve of1.8 million oz @ 3.3 g/t.

Jan 1, 2004

By C. L. Kosmoski, B. M. Eiter, B. P. Connor

"In the recent past, the mining industry has witnessed a substantial increase in the numbers of fatalities occurring at metal and nonmetal mine sites, but it is unclear why this is occurring. One possible explanation is that workers struggle with identifying worksite hazards and accurately assessing the associated risk. The purpose of this research was to explore this possibility within the mining industry and to more fully understand stone, sand and gravel (SSG) mine workers’ thoughts, understandings and perceptions of worksite hazards and risks. Eight mine workers were interviewed and asked to identify common hazards they come across when doing their jobs and to then discuss their perceptions of the risks associated with those identified hazards. The results of this exploratory study indicate the importance of workers’ jobrelated experience as it applies to hazard identification and risk perception, particularly their knowledge of or familiarity with a task, whether or not they had personal control over that task, and the frequency with which they perform that task. IntroductionAccording to the U.S. Mine Safety and Health Administration (MSHA, 2015a), 37 mine workers were fatally injured in accidents at metal and nonmetal mine sites between October 2013 and January 2015, following a record low of 16 in 2012 and in 2011. In 2014 alone, 29 mine workers were fatally injured at a metal or nonmetal mine site, and 52 percent of these fatalities occurred at a surface stone, sand or gravel (SSG) mine. In January 2015, Joseph A. Main, Assistant Secretary of Labor for Mine Safety and Health wrote to stakeholders in the metal and nonmetal mining community and identified several areas where improvement was necessary to promote the health and safety of mine workers. One area identified was an increased focus on “daily and effective workplace exams to find and fix hazards” (MSHA, 2015b).Hazard detection is challenging in the mining industry, despite the existence of regulation. Mining is a major undertaking involving the use of complex heavy machinery, equipment and processes as well as numerous and diverse worker activities that take place in a dynamic, challenging environment (Scharf et al., 2001). In other industries that are similarly dynamic and unpredictable, such as the construction industry, a large proportion of hazards go undetected (Carter and Smith, 2006). It is critical that miners are able to both recognize worksite hazards and accurately assess the risk associated with the hazards, because their health and safety depend on their deciding whether and how to remove hazards and mitigate risks."

Nov 1, 2016

By D. McElhinney, K. Mohamed, T. Batchler, T. Matthews

Steel props are a type of standing support utilized in coal mines to support mine roof. In addition to the vertical roof loading, sometimes the steel props are subjected to lateral loading of spalled ribs. To enhance the safety of mine workers, the performance characteristics of the steel prop was studied under different scenarios of vertical and lateral loadings. Quik Stik props were used for use in this study. A uniaxial compression loading test was conducted for the Quik Stik prop assembly (inner and outer tubes, ball bearings, collar) to investigate the loading mechanism of the prop. Rupture tests were conducted for the inner and outer steel tubes of the Quik Stik props to estimate the yielding strength of the steel tubes. Nine Quik Stik props of 8-ft high were tested using the Mine Roof Simulator (MRS) at the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh research facility. Three props were tested under vertical loading to measure the vertical loading capacity of the props. Six props were tested under lateral loadings with low and high roof-to-floor convergences to measure the lateral loading capacity and the retained vertical loading capacity of the props during lateral loading. Vertical loading tests showed that the tested props could be classified as yieldable supports with a stable load capacity of about 110 kips to 140 kips. Lateral loading tests showed that the vertical load capacities of the tested props were diminished because of applying lateral loads, and the props behaved as nonyielding supports with a maximum lateral load capacity of about 8.5 kips to 9.5 kips at stable lateral displacement up to 3 inches.

Feb 1, 2023

By Yousef Ghorbani, Abolfazl Danesh, Fatemeh Kazemi, Ataallah Bahrami, Morteza Abdollahi

The abstract highlights the impact of flocculants used in the middle thickener of a copper-molybdenum plant on both process water quality and molybdenite floatability. The study investigates the effect of a starch-based flocculant (wheat starch) on the efficiency of the middle thickener and molybdenite flotation. The findings indicate that the presence of starch influences the settling behavior of particles with different shapes, and the dosage of starch affects both molybdenum recovery and the presence of copper minerals in the molybdenum concentrate.

Mar 7, 2022