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By Saul J. Escalera

Mechanisms involved in the depression of the sulfides: pyrite, chalcopyrite, galena and sphalerite with potassium permanganate have been investigated. Flotation tests were conducted using potassium amyl xanthate, Z-6, and pine oil in the absence and presence of potassium permanganate at around pH = 6. 5 naturally yielded by the sulfides in the pulp. On the basis of crystal chemistry considerations, the amount of xanthate adsorbed by the sulfides depends on the amount of sulfur and metal ions present on the surface; thus, the avidity of the sulfides for xanthate should increase in the order: sphalerite C chalcopyrite 4 galena 4 pyrite, and the ease of depression response to the permanganate action should be in the same order. Depression of the sulfides in the system occurs primarily due to the removal of the collector ions by the permanganate ions to form manganese dioxide and dixanthogen according to the reaction: 3 M(RX)2 + 2 Mn04 + 4 H20 2 ? MnO2 + 3(RX-XR) + 3 M+2 8OH where M represents the metal ion, RX the xanthate ion and (RX-XR) the dixanthogen molecule. Results seem to indicate that the permanganate ions play a triple role in the system: (1) they convert xanthate ions into dixanthogen, (2) they further oxidize the mineral surface and (3) if present in excess, they may oxidize the xanthate beyond the dixanthogen stage with the formation of CO2, H20 and SO4. All sulfides, except for chalcopyrite, showed a depression response in the order predicted regardless of the order of addition of xanthate and permanganate reagents. Chalcopyrite did not depress as easily; this behavior may be due to the avidity of the colloidal MnO2 to adsorb Cu+2 ions on its surface, this would destabilize the colloid making it coalesce with the formation of a layer of precipitated MnO2 on the surface of the mineral. The presence of this layer would prevent further action of the permanganate ions on chalcopyrite.

Jan 1, 1970

By Xiaohong He, Qing Yu, Kaixiang Zhang, Rui Guo, Minghua Lin, Haoyu Miao

With the increasing depth of coal mining, the coal mine shaft traverses’ strata conditions become more and more complex. Shafts are often located in deep thick strata with unstable aquifers, and coal mining requires short-term rapid drainage of aquifers; the additional stress caused by aquifer water drainage is the direct cause of the shaft-lining failure. Over the years, many experts have conducted research on the shaft-lining damage caused by the consolidation and subsidence of the soil layer induced by the long-term drainage of the aquifer. On this basis, this paper conducts an in-depth study of the dynamic change of the pore water pressure of the aquifer in the short-term drainage and its influence on the response of shaft-lining strain and surface subsidence. The result shows that the Mandel effect of pore water pressure around the shaft-lining is obvious at the beginning of drainage, and the pore water pressure suddenly increases; the increase is independent of the drainage rate, which leads to the sudden increase of the shaft-lining strain value unrelated to the drainage rate. The result also shows that with the gradual dissipation of pore water pressure, the increase of shaft-lining strain is positively related to the drainage rate and negatively related to the drainage distance, and the variation trend of horizontal strain is greater than that of vertical strain, which appoints the main cause of shaft-lining damage.

Mar 16, 2023

By Robert R. French

Commercial grade gypsum beds up to 16 feet thick is present in southwestern Indiana. The major deposits are found at a depth of 350 feet to more than 500 feet below the surface. The ore body averages about 75 to 95 percent gypsum. Two companies are currently exploiting a deposit which underlies an area of several square miles near Shoals, in Martin County. Another deposit has been located in southwestern Owen County but has not been developed. The Indiana Geological Survey is currently drilling in Greene County and is considering further exploratory work in Perry end Dubois Counties.

Jan 1, 1965

By R. J. Sweigard, R. V. Ramani

Productive and beneficial use of reclaimed surface-mined land is a concern of industry, government, and the general public. A process has been developed that will aid mine planners and public planners in the evaluation of postmining land use potential. This process involves the application of site planning principles to surface-mined land in a way that ensures productive end use of reclaimed land. The process consists of 10 basic components and is iterative in nature. Termination of the process depends on the amount of data collected and the evaluation requirements of each mining site. The analysis centers around the economic, environmental, and social impacts of the alternative land use plans.

Jan 1, 1987

By C. E. Semler

A 5 year test program, involving on-line, in-vessel exposures at Barrick Goldstrike Mines. Inc. has provided valuable information and experience about the materials and designs for brickwork linings in pressure oxidation autoclaves. A variety of brick and mortar products have been evaluated. Properties before and after exposure are used to document the performance. Benefits have included the development of a new silicate mortar improved understanding of brick requirements and increased autoclave operating time between maintenance shut-downs. More improvements are expected in the future based on further information from the test program.

Jan 1, 1997

By J. V. Thompson

The Powderhorn complex as a source of perovskite (calcium titanate) containing about 1.5% rare earths has been examined in several recent feasibility studies. Much promising exploration and process research has been done in recent years. This paper is presented with cautious optimism and with the acknowledgment that there may be some technical and economic areas yet to be explored. The Powderhorn carbonatite and alkalic stock in Gunnison County, Colorado, lies about 203 airlines km southwest of Denver at an elevation of 2450 to 2750 m (see Figures land 2). All of the mineable ore bodies are owned by Buttes Resources Company of Houston, Texas.

Jan 1, 1990

By Gerald H. Luttrell, Seyed Hassan Amini, Aaron Noble

One of the most important processing engineering tools for designing mineral processing facilities is linear circuit analysis. This technique, originally conceived and developed by Meloy, Williams, and Fuerstenau nearly four decades ago, provides fundamental insights regarding how unit operations interact and respond when arranged in multi-stage processing circuits. Researchers have successfully utilized this tool to improve the operating performance of industrial processing circuits incorporating coal spirals, magnetic separators, mineral spirals, and eddy current separators. More recently, advanced versions of this tool have also been developed to provide a standardized framework for circuit mass balance calculations, to output exact analytical solutions to mass yield and value-based efficiency expressions, and to estimate uncertainty propagation in separation circuits. This article reviews the historical development of linear circuit analysis, describes how the technique has evolved to address more complex circuit design problems, and presents industrial case studies that highlight the importance of this process engineering tool.

By A. J. Stewart, R. L. Shufflebotham, D. W. Ferguson, T. L. Page

The Inter-Island Tunnel is a 7.7 kilometer (25,160 foot) long by 3.5 meter (11.5 feet) diameter concrete lined tunnel through the Cambridge formation below Boston Harbor. Constructed as part of the Boston Harbor Project, this tunnel will bring untreated wastewater from the MWRA’s South System headworks facility at Nut Island in Quincy, MA to the new Deer Island treatment plant. A myriad of problems delayed the construction of the tunnel. These problems included salt water inflows of over 22,000 liters (5,812 gallons) per minute, a major fire in the access shaft, weak rock and soil collapsing on the tunnel boring machine, and hand mining operations.

Jan 1, 1997

By C. B. Queja

Flexible synthetic membrane liners have become a standard facet to copper and gold heap leach pad design. While gold heap leach operations have utilized most types of synthetic liners, copper leach operations have commonly only been lined with polyethylene. The objective of this study was to determine if there are any chemical reasons why other synthetic membrane types could not be used to line a copper heap leach facility. With engineered consideration, the flexible membrane liner under the ore pile serves two purposes. The first provides a near impermeable boundary which aides greatly in the collection of the metal laden process solution. The second advantage to the flexible membrane is the almost non-permeable barrier to benefit increased environmental awareness that has led to an increase in solution containment technology. The Environmental Protection Agency (EPA) has developed a compatibility test for solutions and membrane liners. The EPA Method 9090 is intended for use in determining the chemical effects of a solution on the physical properties of the flexible membrane liner material intended to contain them. Data from these tests would assist in deciding whether a given liner material is acceptable for the intended application.

Jan 1, 1995

By Shahab Alizadeh, Ahmad Khodadadi Darban, Mehdi Mohseni, Mahmoud Abdollahy

This study probed the selective separation of lanthanum and yttrium in a nitrate medium in the presence of aluminum and calcium impurities using di-(2-ethylhexyl) phosphoric acid (D2EHPA). The factors studied in a central composite design (CCD) included extractant concentration, pH, concentration ratio of total impurities to rare earth elements, and interaction of these three factors. The extraction mechanism and types of extracted metal-containing species were delineated by the slope analysis method. The obtained thermodynamic data showed that lanthanum and yttrium extraction by the D2EHPA extractant was exothermic. The extraction of both rare earth elements was accompanied by an entropy reduction. The negative magnitude of ΔS in yttrium extraction reaction suggests stronger D2EHPA-Y(III) complexation relative to La(III). As entropy decreased and enthalpy increased, the extraction process became unspontaneous. Using the proposed flowsheet, lanthanum and yttrium products with > 90% purity were obtained.

Aug 10, 2021

By Basak Anameric

This study reports preliminary feasibility investigations for utilization of the selective carbothermic reduction and smelting (SCRS) processing scheme to beneficiate low-grade iron-manganese (Fe-Mn) mineral deposits from MN, USA. The study includes laboratory-scale demonstrations using an induction furnace and production of various products by manipulation of operational parameters. The products include alternative iron (Alt Fe), high carbon ferromanganese (HC FeMn), alternative silicomanganese (Alt SiMn), and upgraded manganese concentrate (Mn conc). All of these products have commercial value and can be used in various applications as raw materials.

Nov 23, 2020

By Jeff Schwoebel, Arcy, D&apos Horner

The Deep Coal Seam Project is a multi- year, large-scale research and development effort between the Gas Research Institute (GRI) and Resource Enterprises, Inc. (REI). The project is being conducted at the Red Mountain Site, a multi-well test site located in the southeastern portion of the Piceance Basin near Collbran in Mesa County, Colorado. The project objective is to develop the drilling, reservoir evaluation, completion and production technology required to produce gas from a thick, deeply buried coal seam. To understand the parameters controlling gas production, project efforts are focused on the Cameo "D" coal reservoir which lies at a depth of about 1707 m (5,600 ft) at the test site. This paper overviews the drilling, testing, completion, and production techniques used on the 1, 2 and 3 Deep Seam wells and implications for resource development.

Jan 1, 1987

The paper describes a practical methodology based on numerical modelling for the prediction of progressive failure of underground mine stopes with cable bolt support. A case study of the 40-761 stope at Kidd Creek Mine, Timmins, Ontario is presented. The stope was mined by blasthole open stoping in 1986 as a lead stope within a mining block between 36-1 and 38-2 levels. Initially designed to peak at 38-2 level, the stope back caved upwards approximately 40m towards 36-1 level. Cable bolts were installed above the stope from 36-1 level after caving had begun. The stope eventually stopped to cave when the falling rock mass encountered a sufficiently high cable density. The paper provides details of the geomechanical data and modelling results of the case study. Numerical modelling is carried out using a finite element package known as e-z tools which has, among other things, a special cable/rockbolt simulation capability.

Jan 1, 1994

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 Paul Nicholas, Raju Gottumukkala

"India’s economy is expanding with rapid urbanization. Improvement in infrastructure is a keystone to the Indian government’s economic plans, including expansion of transit systems. Most of these systems are designed with elevated and underground sections. New Delhi, a city of 23 million people, suffers from heavy traffic congestion and pollution. The transit (metro) system is seen to be of critical importance. Phase 3 of the Delhi transit system project is 140 kilometers (km), with 40 km of twin-bore tunnels requiring 35 tunnel boring machines (TBMs) for construction. Transit systems are also under design or construction in Chennai, Bangalore, Kolkata, Hyderabad, Jaipur and Mumbai. Most have twin-bore tunnels. At present, 55 TBMs are operating on underground metro construction, and future projects will increase this number. This paper highlights the unique challenges of construction of underground metro systems in highly congested urban environments, using Kolkata and Delhi systems as examples. INTRODUCTION The first transit system in India was constructed in Kolkata (India’s third-largest city by population.) This line is 28 kilometers (km) in length, has underground and at-grade sections, was built in phases, runs north/south, and has 24 stations. This project was sanctioned in 1972, started construction in 1984, and was completed in 1995. The tunnels were constructed primarily by cut and cover methods with some open-face, compressed air shield tunneling. In 2006, the urban transport policy recommended construction of transit rail systems in all urban cities with a population exceeding 2 million. Further, in 2014 the central government stated that it would assist in financing transit systems in all cities with a population of over 1 million. In 2015, the central government approved the development of transit systems in 50 additional cities across India with a budget of $75 billion (see Figure 1). Transit development is just part of a huge expansion in planned rapid transport systems, which include metro, bus, high-speed rail, and monorail systems. Metro systems will include elevated and underground sections with twin-bore tunnels and underground stations. In the Delhi/National Capital Region (NCR), now the largest city in India by population, Delhi Metro Rail Corp (DMRC) was formed in 1995 as a joint venture company between the central government and Delhi state. DMRC operates the Delhi metro system. (see the case studies described later in this paper). DMRC has developed an external function to carry out studies and to offer consultancy to other cities planning transits. Since its inception, DMRC has produced Detailed Project Reports (DPRs) for every metro and monorail project in India. In 2012, DMRC became a partner in the management consultancy for Jakarta Mass Rapid Transit System, its first project overseas. DMRC became a model organization for other cities to follow. These cities have included Chennai, Hyderabad, Kolkata, Bangalore, Jaipur, Mumbai, Ahmedabad, and Nagpur. Other cities (e.g., Lucknow and Patna) are in the metro planning phase. Metro systems are under construction or partially operating in Hyderabad, Bangalore, and Jaipur."

Jan 1, 2016

By Richard J. Robbins

Mechanical raise and tunnel boring are new techniques to most of the mining industry. Coal, salt and potash have been bored economically, but until recently boring machines were not designed specifically for rock boring in underground mining. The construction industry has led the field of rock boring since 1854 when the first tunnel boring machines built by James S. Robbins and Associates went to work at Oahe Dam, South Dakota. Since that time the company has built boring machines for tunneling through ground conditions varying from cohesionless soil to hard rock, and in diameters ranging from 7 feet to 36 feet 8 inches. It is natural that the construction industry got the jump on mining with the use of mechanical rock boring equipment. Mines have looked for the long range answer to problems of underground excavation and they have chosen proved and established techniques they expect to employ for the next ten or twenty years. The mine development was laid out to accommodate these techniques.

Jan 1, 1964

By S. P. Winkelmann

The expansion in gold production in the Carlin 'Trend over the last few years has been one of staggering proportion. To increase gold production while minimizing capital requirements and providing for the safe and efficient mining and processing of ores has required a tremendous effort by the Mine Engineering group at Newmont Gold. This paper discusses the organizational changes implemented to effectively deal with a full range of engineering problems and how the Newmont Gold Mine Engineering group dealt with these problems. Specially developed computer software and their applications will be explained. Improvements in the techniques used in converting geologic resources into reserves, and in scheduling the mining of multiple pits to feed multiple processing facilities, as well as ore control procedures are presented. Current mine engineering practices are discussed.

Jan 1, 1990

By Barbara J. Arnold

A coal's size distribution, clay content and moisture content can affect its handling behavior, but the combined effects of these properties and the effects of other properties are not known. Research underway at CQ Inc.' s (formerly EPRI' S) Coal Quality Development Center (CQOC) and at Iowa State University (ISU) will answer these questions as part of a four-year project to develop a coal handleability index for utilities to use when specifying coals. This paper will present preliminary data from the first year of the project, which focused on obtaining data on the chemical and physical properties of various coals and their measured handling properties. Additionally, size, ash and moisture analyses and shear test data for several coals used at one power plant will be presented along with correlations between these physical and chemical properties and the measured handling properties. These data lead to the conclusion that, while moisture content-is the most important variable, the amount of -325M (-0.044 mm) coal fines is a significant factor in determining coal handling behavior.

Jan 1, 1990

By R. L. Bullock

For many years, the combined efforts of machinery manufacturers and mine operators have endeavored to achieve greater productivity from the men involved and the machinery and capital invested, by developing methods to drill blast holes more effectively. Obviously, this means much more than simply developing a drill that will drill a single hole faster. Considerable attention over these years has also been given to methods of carrying and positioning the drilling machine on versatile jumbos, whereby the man's time can he better utilized by the faster drilling machines. Likewise, the art of blasting to utilize the holes that were drilled to achieve the maximum amount of fragmented ore and the methods of moving the broken ore have also progressed. But each phase of the production cycle just described must be made to balance with the other phases of the work. Obviously, major breakthroughs in only one phase don't always generate more "rock in the box" per manshift. Yet, through the persistent effort of the machinery developers and the researchers, the progressive attitudes of mine managers, backed by corporate capital investments, and battle after battle at the operating level, progress is made. Then, if the innovated system is good enough to "stick", in a few years it becomes the system that the newer method must replace, after the same repeated struggle. This is the situation that many mine operators find themselves in today, Looking at their production cycle, which is assumed to be efficient and balanced between drilling, blasting and materials moving capabilities, they tend to guard any visable disruption of the balance of that day's production, and many would prefer to maintain the status quo indefinitely. Yet, if history repeats itself, we can expect any major breakthrough in the cycle to trigger other innovations in the

Jan 1, 1975

By Yohan Cha, Eun-soo Hong, Gye-Chun Cho

"Rapid population growth and scarcity of space have led many developed cities to bury supply facilities. In line with this, utility tunnels have been employed in Korea since the 1970s. However, approximately 70% of structures were installed more than 20 years ago, in response to the issue of ageing, tunnel enlargement has been proposed. The aim of this study is to investigate geo-mechanical behavior due to tunnel enlargement. Tunnel enlargement methods have been researched to suggest a optimal method. A finite element analysis is conducted to evaluate ground behavior by the expansion of internal space. Vertical displacement and settlement trough width are investigated according to ground stiffness and different enlargement size. It was determined that displacement is affected by the enlargement size and ground stiffness. Based on the deformation results obtained from the numerical analysis, it is possible to predict ground behavior and stability upon tunnel enlargement. INTRODUCTION Various infrastructures such as electric lines, communication lines, gas pipes, and water pipes are jointly accommodated by utility tunnels. These utility tunnels improve the aesthetics of urban areas and help ensure stable supply. The first utility tunnel in Korea was adopted in 1978 and new tunnels are still being installed with the development of new suburb cities. Nevertheless, about 70% of the utility tunnels were installed over 20 years ago and they are still being used through ongoing repair. Moreover, 90% of utility tunnels were installed before 1995. With aging of the nation’s utility tunnels various problems such as concrete deterioration and scarcity of capacity have arisen. As solution, reconstruction has been considered. Reconstruction can enlarge space and improve the performance by replacing existing structures. For reconstruction, two routes have been proposed: underground excavation and cut and cover. In order to avoid traffic problems caused by road occupation and civil appeals during construction projects, underground excavation is the more attractive option. Tunnel enlargement methods have been classified (Seo et al., 2008; An et al 2013) and major considerations during tunnel enlargement have been outlined (Beak et al., 2007). Enlargement construction cases on road tunnels around the world were introduced (Kim et al., 2012) and the deformation curve during tunnel expansion was proposed to investigate the range of protection that should be offered (Kim et al., 2008; Beak et al., 2011). However, tunnel enlargement technology is limited to road tunnels and railway tunnels. Hence, a study on shallow box tunnel enlargement is required for practical application."

Jan 1, 2016