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By NEHA PANDEY, V.K. REDDY KALLAM, SUNIL KUMAR TRIPATHY, ARIJIT BISWAS

This work discusses the sulfur dioxide (SO2) leaching of low-grade ferruginous manganese ores to selectively recover manganese (Mn) as manganese sulfate (MnSO4), followed by electrowinning of the purified MnSO4 to produce electrolytic manganese dioxide (EMD). The effects of the leaching process parameters on Mn recovery were studied, and the leaching duration and SO2 flow rate were found to have significant effects. Under the optimum conditions derived for grade 1 ore (with total Mn content of approximately 17.16 percent), the specific SO2 requirement (SSR) — that is, the SO2 flow rate per gram of Mn in the leach slurry — was calculated to be 0.014 L/min. At the SO2 flow rate calculated using SSR for grade 2 ore (with total Mn content of approximately 26.29 percent), a Mn recovery rate of 94 percent was realized. Electrowinning of the purified MnSO4 generated after leaching resulted in EMD with 88.01 percent purity and a γ structure.

Sep 1, 2022

By C. Athanassopoulos

Geomembranes have been used in the mining industry since the early 1970s in solution and evaporation ponds, tailings impoundments, and heap leach pads. Traditionally, heap leach pad lining systems have consisted of a single geomembrane liner placed directly over a prepared subgrade of locally available soil. Heap fills are constructed by placing a layer of highly-permeable drainage stone (overliner) over the geomembrane. Crushed ore is then placed on the leach pad in 3- to 10-m (15- to 30-foot) thick lifts, sometimes reaching final heights of several hundred feet. The crushed ore is irrigated with a chemical solution which dissolves the precious metals from the ore. The nature of the chemical leaching solution depends on the metal being targeted. Low pH sulfuric acid solutions are generally used to leach copper and nickel; high pH cyanide solutions are used to leach gold and silver. The metal-laden pregnant leach solution (PLS) passes down through the ore pile and is captured in a drainage system. Metals are extracted from the leach solution and the solution is then recycled back onto the leach pile. When under load, geomembranes are vulnerable to damage from large stones both in the soil subgrade and in the overlying drainage layer. Although intact geomembranes are virtually impermeable, installed geomembranes will have a small number of holes due to imperfect seams or damage during construction and filling operations. These holes serve as open pathways for leakage into the soil below. Smith and Welkner (1995) estimated liner leakage rates ranging from 5 to 10,000 L/ha/day, depending on the type of heap pad liner and level of construction quality assurance (CQA). Thiel and Smith (2003) reported liner leakage rates up to 2,000 L/ha/day for a valley fill facility with heads ranging from 15 to 35 m.

Jan 1, 2011

By T. V. Johnson

The microstructural relationships in dolomitic fluxed taconite pellets were studied. The influence of basicity (in the range 0.75 to 2.1) and firing temperature (to 1340°C) on the grain structure, macrostructure, and mineralogical phase relationships are described. Extensive slag bonding of hematite grains begins at temperatures between 1220 and 1230°C, and results in fundamental changes in grain structure. Successive temperature increases result in little change in grain structure until 1340°C, when extensive coalescence of the hematite grains begins.' Increasing flux additions have little effect on grain structure but greatly influence pore character. The compressive strength decreases with increasing flux addition, increases with increasing firing temperature, and is related to the macrostructure of the pellet. The compositions of the slag phases are represented on the CaO-Fe2O3-SiO2 phase diagram, and the compositional path of slag development is described.

Jan 1, 1980

By J. A. Murray

Maintaining satisfactory air quality in electrowinning tankhouses is problematic and costly, particularly as plant operating current densities have increased. Conventional approaches have not proved completely effective. These include the use of beads, hollow spheres, surfactants and coalescer devices. They require powerful ventilation systems to be installed. As workplace and environmental regulations become more stringent, containment of the acid mist at its source is more attractive. An electrode cap system based on this approach has been developed and tested in two commercial copper electrowinning tankhouses.

Jan 1, 1996

By Valérie J. Bertrand, Richard W. Lawrence, Marcos G. Monroy

Two cemented paste backfill (CPB) formulations containing pyritic tailings were leached in deionized water in flooded and alternating air-flooded environments and in a simulated acid rock drainage-type (ARD) solution. Scanning Electron Microscopy (SEM), solid phase chemistry and acid-base accounting measurements documented the weathering characteristics of the CPB samples. Short-term exposures of the portland-CPB samples preferentially dissolved the cement binder to a greater extent than slag-Portland CPB mistures. In all cases, the added neutralizing potential provided to backfill by cement was short-lived and insufficient to neutralize the acid generating potential of the mixture.

Jan 1, 2000

By Louis M. Schlesinger, Michael J. Garska, Joel F. Hutwelker, James T. Jr. Tanner

A pilot plant was constructed and operated to investigate the column flotation of 20 x 200 mesh North Carolina phosphate ore, using high throughput, high solids operating conditions developed at the NCSU Minerals Research Laboratory. Flotation was performed at 45% solids in a 9.5 cm (3.75 in.) diameter by 2.26 m (7.4 ft.) tall column at throughputs of 19.1 t/hr/m2 (2.0 stph/ft2) and 31.7 t/hr/m2 (3.3 stph/ft2). Recoveries in excess of 98% of the phosphate value were obtained at the lower throughput -- while obtaining concentrate grades containing over 28% P205 (61.2% BPL) at that recovery. Recoveries of about 95% of the phosphate value were obtained at the higher throughput, while making a concentrate averaging 27.6% P205 (60.3% BPL). In addition, a better understanding of the variables governing the column flotation of coarse nonmetallic minerals was gained. Variables examined included superficial air velocity, throughput (superficial feed velocity), frother type, frother dosage, and bias rate.

Jan 1, 1993

Asgco’s design of the Arrowhead Ceramic Lagging provides solutions to problems experienced with conveyor belt slippage around the drive pulley and severe wear problems on snub and bend pulleys. Asgco has developed a range of pulley lagging from ceramic, drive rubber and non-drive rubber lagging that is available in abrasion-resistant SBR and MSHA grade rubber for conveyor pulleys from slow belts all the way through to high-speed, high load belts. There is a growing need for a maintenance-free and reliable pulley lagging to ensure conveyor belts run to their highest efficiency.

Jan 1, 2006

By O. B. Bucklen

The Coal Research Bureau of the School of Mines at West Virginia University, using a modified design of a Russian flotation device, was able to obtain a clean coal product containing 7.64 percent ash with 94 percent yield and 97 percent coal recovery. This favorable performance was obtained with the semi-pilot scale flotation cell operating as a simulated three stage unit on slurry taken from the fine coal circuit of a coal preparation plant. This experimental device, consisting of a sheet metal cyclone-like unit mounted on a U-shaped uplift pipe, uses a combined flotation and cyclone action to beneficiate the minus 14 mesh partially cleaned feed product. In addition to providing comparable analytical results, the airlift-cyclone possesses other attractive features among them being a low capital expenditure, utilization of moderate plant floor space, efficient "operation on high density feed slurry, and absence of moving parts.

Jan 1, 1964

By T. Hawthorne, H. Barnes

Homestake Mining Company has developed an estimating model, based on other closed projects, to audit and prepare new estimating plans. The results of recent closure audits reveal that the original budgets were often insufficient to cover the present expected expenses. Some of the major areas where technical challenges and costs are increasing include heap leach pile detoxification and rinsing, tailings dam closure, water management and treatment, abatement of contaminated soils, and many others. Risk and sensitivity analysis of each category will develop a level of confidence in the estimate and allow management to focus on the pertinent issues. Periodic audits of closure plans and costs throughout the life of mine serves to focus management attention on the complete costs of production. This will result in improved overall planning and management, and reduce the number of missed opportunities for savings.

Jan 1, 2000

THE QUARTETTE Mine near Searchlight, NV, a mine that first operated in the 1890s, could begin processing ore again by September. Jetco Enterprises Inc. plans to work through the tailings and ore close to the surface followed by plans for an openpit mine. It is one of at least three new mining efforts in the region, the Associated Press reported. Another is north of Searchlight, with yet another across the Colorado River in Arizona, east of Bullhead City. Gold mining is rare in southern Nevada. The area generally lacks the rock type that contains gold deposits. Restrictions on federal wilderness areas and protections for the desert tortoise also play a role. Gold veins in the region are generally small and erratic in length and height, Bill Durbin, a geologist and chief of southern Nevada operations for the Nevada Division of Minerals told the Associated Press. L.R. Tad Tinnell, president of Jetco Enterprises, has long eyed the mine. From 1993 to 1995, he explored and drilled on the property, which was still owned by Searchlight Mercantile.

Sep 1, 2013

By Gökhan Çevikbilen, Ümit Karadoğan, Sevde Korkut, Berrak Teymur

This study proposes a methodology for dewatering of mine waste using a multistage process, combining geotextile tubes and anionic polyacrylamide (PAM), which accelerates the recycling process of water for aggregate mine waste facilities. For this purpose, waste from a rock quarry located in Istanbul was investigated. Flocculation tests revealed that the use of anionic PAM at an optimum dosage reduced sedimentation time and decreased turbidity. The compatibility of geotextiles and mine waste conditioned with different dosages of the effective PAM was evaluated by rapid dewatering tests, considering the water content of the filter cake, amount of infiltrated solid content, and rate of filtration. Geotextile dewatering tests were also performed on PAM-free and conditioned suspensions. The dewatering process was optimized by the use of a geotextile tube in two stages: (i) on the unconditioned suspension and (ii) on recovered PAM-conditioned leachate. Directing PAM-free non-hazardous soil-based material obtained in stage i to alternative beneficial uses is suggested, to minimize the volume of waste. Furthermore, recycling of the effluent obtained at the second stage of the proposed method will ensure more efficient water reuse

Sep 29, 2022

By Ralph W. M. Lai

The liquid membrane separation process was first patented in 1968 for separating hydrocarbons.(1-4) This stimulated many researchers to join in the area of separating organic compounds. l Since then, its applications have been extended to the removal of contaminants from waste water,(12-33) encapsulation of enzymes and/or microorganisms for reaction and/or separation, (24-28) oxygenation of blood (artificial lung),(19) removal of toxins from blood (artificial kidney)(26,20) and metal extraction.(31-63) This paper discusses the possible process schemes for using liquid membranes to separate and concentrate copper ion from its acidic leaching solution.

Jan 1, 1982

By U. K. Custred

Who We Are Farmland Hydro (FHLP) is a Limited Partnership formed by Farmland Industries, the largest U.S. farmers’ cooperative, located in Kansas City, MO, and Norsk Hydro, a large Norwegian company engaged in fertilizer, petroleum and the specialty metals industry. Both of our parent companies have a long history of commitment to the fertilizer industry. This year, Farmland Industry celebrates its 71st year in the business, and Norsk Hydro celebrates its 100th operating year! We employ approximately 300 associates in Central Florida. What We Do Farmland has been active in Hardee County, FL since the 1970’s as a large landowner and citrus grower. We plan to expand this activity into phosphate rock mining. The phosphate rock produced here will be shipped to our nearby chemical fertilizer complex in Polk County, where we produce quality phosphate products - liquid and granular fertilizers. Of the phosphate rock mined, 90% is used to make fertilizer. Other uses include animal feed, vitamins, medicine, light bulbs, soft drinks, film, flame resistant fabric, optical glass, toothpaste, bone china and other consumer products.

Jan 1, 2000

By Stanley Noss

One need be neither an historian nor technologist to recognize that activi¬ties related to the conversion of coal to other usable energy forms have been active for nearly fifty years. The degree of such activity and its evolution to significant commercial proportions has, however, fluctuated widely with world circumstance. For the past decade there has existed both a consistent technology evolution effort in classic R & D proportions, and a mainstream commercial acti¬vity but in rather modest proportions when viewed from the vantage point of world energy needs. But the chain of events wherein it became increasingly obvious that we were in energy trouble irrespective of world politics, spurred alternative energy source activities in the fossil fuels areas. The oil embargo of 1973-1974 made the obvious even more so and provided additional emphasis for the need of such alternatives. Yet the preponderance of these added expenditures and activities (with one notable exception which is the subject of this discussion) has been focused on the intended identification of the best or ultimate process by means of analytical and modest empirical means, whereas our circumstance dictates a bold, higher-risk effort to prove the viability of coal conversion as an industry on a real-time, real-size, real-economics basis. With such proof on hand, industry demands in all related areas will provide the stimulus, motivation and environment for all processes. There is both need and room for many who will compete for a meaningful segment of this new industry which can grow at a rate never seen before in our growth history. The single program in the world today oriented specifically toward the goal of proof of industry viability is the Energy Research and Development Administration's CBF (clean boiler fuels) Program for which COALCON is proud to be the prime contractor.

Jan 1, 1976

By Edward A. Nowatzki

The purpose of this paper is to present an example of the application of a theoretically derived mathematical model for track-soil interaction to the evaluation of the mobility of large-scale mining equipment used in open pit operations. The model described by Karafiath and Nowatzki (1978) and presented in detail by Karafiath (1978) was used to predict the performance characteristics of four different bucket wheel excavators (BWEs) on rwo types of copper mill tailings at various moisture conditions. The BWEs considered In the analyses are two-and three-tracked continuous excavators. Most have boom-mounted rotating buckets and swinging side- or rear-discharge conveyors. The analyses were performed at the request of Dames and Moore for the Kennecott Corporation's proposed remining of selected tailings deposits at the McGill, Nevada, concentrator. The objectives of the analyses were to determine whether BWEs would have sufficient mobility In the tailings deposit to achieve satisfactory production rates, and TO compare the predicted performance of the various BWEs evaluated. Good qualitative agreement was obtained between the results of the theoretical analyses performed for the McGil1 operation and the actual performance of BWEs in two South African gold mine tailings impoundments.

Jan 1, 1980

By M. T. Webster

Views about the proper aim of public policy are, of course, matters of perspective and debate. Regardless of perspective, one would assume some consensus around the view that public policy ought to encourage mine operators to seek independent and critical assessments of worker safety and health at their operations through voluntary auditing. However, a review of the law on this topic shows that there is little to no manifestation of such a policy. Indeed, the balance of this paper, with a couple of exceptions, is devoted to the existing legal pitfalls that should be considered before a safety and health audit is conducted at a mine. While attorneys, particularly litigators like the author, might tend to focus on the potential problems that could arise from any given situation, the fact that most of this paper is devoted to potential legal concerns associated with auditing is a realistic reflection of the current state of the law. Specifically, this paper addresses the interplay between voluntary safety and health audits conducted at mines regulated by the Mine Safety and Health Administration (MSHA), and the administrative and civil legal issues related to such audits. The paper first provides an explanation of how and by whom an audit is conducted. The paper also addresses whether voluntary safety and health audits may be considered privileged and kept confidential in administrative and civil proceedings. Finally, selected legal issues related to such audits that could arise in administrative and civil litigation are discussed.1

Jan 1, 2012

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

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

May 23, 2022

By M. Guney, A. R. Bell

In Mindola mine on the Zambian Copperbelt, there is a plan to extend the current production level of 1.2-1.5 km (3,900-4,900 ft) with five additional production levels. Research work indicated that the present total heat output of 38.6 MW will inevitably increase to 63.2 MW in 25 years. Estimated WB and DB temperatures, representing the total heat generation in stope faces and development headings during these same periods are predicted to increase to 33.8/40.2°C (93/104°F) and 35.3142.10C (95/108°F) respectively. It is assessed that the nominal refrigeration capacity needs to be progressively increased to 9, 000 MW.

Jan 3, 1984

By S. A. Montague

In spite of the many new insulating materials, both synthetic and manufactured, that have been put on the market since the end of World War II, and notwithstanding the many millions of dollars applied to the development of synthetic mica, natural block mica1 is still a most indispensable insulator in various electronic components. It will remain so, barring some spectacular break-through in research that might provide a substitute fully acceptable as a replacement for mica in all of its superior properties. But this is not to say the future for mica is assured, or free from serious problems. Technological advances have created problems requiring a solution to be found if future requirements are to be filled.

Jan 1, 1962

By V. L. Ketellapper

This paper discusses the technical issues and stakeholder collaborative processes which resulted in achieving a balance between the reclamation of abandoned mine sites, providing affordable housing, and preservation of open space at the French Gulch Site. Through this process, it was discovered that mine site reclamation would need to be conducted in conjunction with two priorities for community sustainable development: providing affordable housing for locals who work in the resort town of Breckenridge, and open space preservation. It was found that conducting these activities concurrently would result in providing resources necessary to complete mine site reclamation. The first phase of the affordable housing development is almost completed. This development resulted in redevelopment of mining impacted lands and was recognized by the U.S. Environmental Protection Agency (EPA) with a National Smart Growth Award in 2002.Negotiations are also underway to preserve the remaining 1,800 acres of land held by the mining company as open space. This transaction will in turn provide resources to address water quality issues associated with mine discharges.

Jan 1, 2004