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By J. F. Papp

In the United States, chromium has been consumed in three major markets: chemical, metallurgical, and refractory. The predominant end use for chromium in the United States is in the metallurgical market as an alloying element in the production of stainless steel. In addition to being a major stainless steel-producing country, the United States is a major world producer of chromium-containing chemicals and has used substantial amounts of chromite ore for refractory applications. Chromium use is not easily further subdivided within the chemical and refractory industries because there is insufficient publicly available information to do so; however, chromium use can be subdivided among metallurgical industry uses based on the American Iron and Steel Institute (AISI) reported shipments of stainless steel by market classification (agricultural, aircraft, automotive, etc.). It is the goal of this study to determine the distribution of U.S. chromium apparent consumption among major markets in the United States. The distribution is expressed in the form of dimensionless fractions that are computed based on documented chromium consumption by major market. The distribution of chromium among markets within the metallurgical market is computed in a similar manner. Distribution factors are first computed for the major markets, then for markets that are subdivisions of the metallurgical market. The distribution of chromium among major markets has changed substantially over the time period of analysis. The fraction of chromium consumed by the metallurgical market has increased while that of the chemical and refractory markets has declined. Within the metallurgical market, the service industry market accounts for the greatest fraction of chromium consumption followed by transportation. Electrical, machinery, and fabricated products markets account for a substantial share of the metallurgical chromium consumption.

Jan 1, 2004

Three computerised sets of minerals information are being developed by New Zealand Geological Survey in co-operation with the Resource Management and Mining group of the Ministry of Energy: 1. Geological Resource Map: a file of information on the location, geology, geochemistry, production, and potential use of individual occurrences of aggregate, mineral, geothermal, coal, oil, and gas resources. The computer program can be used for search and retrieval of information and the production of maps and tables. The data is being published as a series of 1:250 000 maps with accompanying text and tables. 2. Minerals Bibliography: an index and retrieval system for mineral exploration related; open-file company reports, N.Z. Geological Survey files, scientific research publications and university theses. 3. Minerals WhoÆs Who: an annotated directory of geologists involved in mineral exploration, mining and research.

Jan 1, 1986

By V. I. Lakshmanan, Dan A. Mackie

Traditional vat leaching methods have had limited success, primarily due to the high cost of loading and unloading the vats. In general, such batch methods are labor-intensive and costly. Heap leaching has emerged as a viable, low- cost alternative, but low recoveries, normally in the 70% range, offer opportunities for improvement. Also increased regulatory guidlelines for effluent and spent heap leach pads disposal offer potential for alternative methods. The Mackie Vat Leaching Jig (MVLJ) has had its incubation at Ortech International, where bench scale through pilot scale testing continues. Design developments and testwork over the past two years indicate that the time may be right for field trials.

Jan 1, 1990

By Brian Gar Wingfield

"The introduction of the QuarryMan laser profile system in 1987, along with the development of the corresponding 3-D software, gave a qualified operator pertinent information about dimensions of quarry highwalls, pattern and hole loading design, stockpile profiles, etc . . . Attributes helpful for this endeavor included surveying, computer, and blasting knowledge. Since not all operators had theseskills, a simpler model, the QuarryAce, was designed to look a t highwall dimensions in 2-D view . Al though less sophisticated than the QuarryMan instrument and its software, it is simpler to instruct in its use and has the ability to determine burdens at different depth levels . An in-house user f r i e n d l y computer program was designed to utilize QuarryAce depth vs. burden data . This program was created to enable laser and computer novices to generate information useful to the everyday blaster."

Jan 1, 1992

By Michel Aubertin

Les digues de retenue de résidus miniers devraient être conçues de façon à supporter les charges les plus défavorables qui puissent être anticipées. Les nombreux incidents survenus au cours des dernières années à travers le monde montrent toutefois que la stabilité de ces ouvrages reste encore problématique. Les cas de rupture les plus courants sont reliés aux glissements le long des pentes, à la liquéfaction des rejets, au débordement des bassins, ainsi qu?à l'érosion régressive et de surface. Après avoir rappelé la nature et l?importance des certains incidents récents, l?origine de ces problèmes est brièvement présentée. On aborde ensuite le lien entre les critères à adopter pour la conception des ouvrages et les risques associés à leur rupture. De nouvelles avenues pour aider à contrôler certains problèmes sont enfin discutées, en mettant l?emphase sur la codisposition des roches stériles dans le parc à résidus miniers.

Nov 1, 2002

By Noriyuki Fujii

It is no need to say that exploitation of industrial minerals has a close relation to development of the industries related. In the first stage, a small scale manufactures were initiated in areas producing some main raw material minerals. China and cement manufactures, for example, were established depending on the local occurrence of raw materials such as kaolin and limestone without exception. That is, the industrial development is greatly influenced by the local production of the raw materials in the stage. With the development of industrial technology, various kinds of raw material minerals are explored to meet the demands of industries in the second stage. New materials become indispensable, and low-grade raw material minerals, which were left as useless, are developed as useful materials. In the stage, the development of raw material minerals is accelerated by that of industrial technology related. However, industries mainly rely on domestic production of the min raw material minerals.

Jan 1, 1981

By J. L. Carr

Continuous mining machines are extensively used in the underground coal mining industry. These machines are typically remote-controlled, and severe injuries and fatalities occur every year when a miner is struck or pinned by the machine. Proximity detection systems offer a means to prevent these types of injuries and fatalities by sensing the presence of a miner and disabling machine motion. Researchers at the National Institute for Occupational Safety and Health (NIOSH)have developed the Intelligent Proximity Detection (iPD) system to provide enhanced protection while minimizing false alarms. The iPD system uses a set of pre-defined rules to determine which machine motions are safe and which would present a potential hazard, and automatically disables only the potentially hazardous motions. This system has been installed and tested on a Joy 14CM continuous mining machine at the NIOSH Office of Mine Safety and Health Research in Pittsburgh. Under laboratory conditions, the achievable accuracy and performance of the iPD system has been quantified with respect to a number of variables including position of the conveyor boom, presence of the machine?s trailing cable, and orientation of the miner-wearable component. Disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Reference to specific brand names does not imply endorsement by the National Institute for Occupational Safety and Health.

Feb 27, 2013

By B. M. Das

Several laboratory model test results for the determination of the ultimate uplift capacity of single and group metal piles embedded in near-saturated clay have been presented. Based on the uplift test results for single piles, the variation of the adhesion factor with the undrained shear strength of clay has been determined, and an empirical correlation for estimation of the adhesion factor in soft and medium clays has been presented. The group efficiency of piles under uplifting load depends on factors such as embedment ratio, undrained shear strength of clay, the number of piles in a group, and the center-to-center spacing of the piles.

Jan 1, 2010

By Susanna G. de Jager, Francis W. Petersen

"To enable the prediction of reagents suitable for fine coal flotation, it is necessary to develop a methodology applicable to different South African coal types. Statistical confirmation of the applicability of this methodology is important to avoid recommendation of reagents on a trial and error basis.The study included 5 coal samples from different collieries and included Highveld seam 3 and 4 coal (as one sample), Waterberg coal (zone 10 -11), Highveld seam 5 upper coal and Witbank seam 2 and seam 4 coal. Seam 3 and 4 (mixture) coal, Waterberg and the seam 5 upper coal were all found to be vitrinite rich coals. The coal characterisation study included petrographic analysis, proximate analysis, float-sink analysis, oxygen-containing functional groups, surface extraction, flotation release analysis and contact angle measurements. Flotation tests were used to validate expectations from the characterisation of the coal samples.RESULTSThe flotation data indicated that all of the coal samples were amendable to froth flotation. The best results were obtained with the Witbank seam 2 coal and the poorest flotation with Syferfontein seam 5 coal. The flotation tests showed that the best reagents to float all of the coal samples studied were iso-decanol and dodecene. These reagents produced flotation products that were near to the release curve, which are the optimum flotation results (obtained when using iso-paraffin as collector). Dodecene resulted in low ash products and iso-decanol in high yield products."

Jan 1, 2003

By J. Ritchey

This report describes the engineering feasibility and economic advantages of using a mobile bridge-type cross-pit belt conveyor system in conjunction with a large dragline to excavate and transport spoils in a typical Western surface coal mine. The studies show that such a system could be built to survive operational and climatic mining conditions, and that its implementation would offer a reduction in both acquisition and operating costs versus conventional mining units of comparable rapacity. Reclamation costs can also be significantly reduced, and the total reclamation process accelerated, making the cross-pit conveyor system attractive to mine Owners and environmentalists alike.

Jan 1, 1976

By G. Belardi, N. Shehu, L. Passeri

"This paper illustrates the possibilities of applying what is essentially a physical soil-washing technique for treatment of soil contaminated by semi-volatile hydrocarbons in order to reduce the level of pollution to that permitted by Italian regulations.The ground around a factory producing lubricating-oil additives consists of silty-sandy soils which have long been contaminated by heavy hydrocarbons, especially branched alkyl benzenes and naphthalene derivatives. Pollution is particularly marked in some zones (hot-spots) where Total Petroleum Hydrocarbon (TPH) values are as high as 7000 ppm. The hydrogeological characterization showed the presence of a gravely soil in a sandy/silty matrix, with big stones making preferential paths to the water circulation. The permeability is 10-5 m/s and the water-table occurs at about 3 m below ground level.After laboratory and pilot-scale studies on representative samples of in-situ soils with TPH between 2700 and 7000 ppm a flow-sheet is proposed for reducing TPH values below the acceptable limits in Italy, namely 700 ppm for hydrocarbons with more than 12 carbon atoms and less than 250 ppm for those with fewer.On the basis of indications provided by laboratory tests a mainly physical treatment process of soil washing has been developed. This is used to clean-up soil from a site polluted by non-volatile hydrocarbons with a high TPH value. The process involves a high-density attrition stage followed by wet screening at 0.5 mm and then wet-gravity separation of the minus 0.5 mm fraction in the centrifugal field.The gravity separation products consist of a light fraction with particle size finer than 15 micron which contains most of the pollutants, and a heavy coarse fraction with TPH values conforming to the limits set by Italian regulations (less than 700 ppm hydrocarbons whose structure contains more than 12 C atoms, and less than 250 ppm of hydrocarbons with less than 12 C atoms)."

Jan 1, 2003

By Jerry D. Pfarr, Gary Loving, David G. McDowall

Introduction The Open Cut is one of the best known landmarks in South Dakota's Black Hills. It is the site of the original discovery of the Homestake ledge, or lead, in 1876. Between that time and 1945, the Open Cut produced about 36 Mt (40 million st) of gold ore, the majority of which was drawn from underground operations. In 1981, a drilling program was undertaken to determine how much ore the old timers left behind. The results of this study indicated an ore body made up of broken and caved ground, and solid blocks in pillars and crowns. Reserves are estimated at about 6.8 Mt (7.5 million st) of gold ore, grading at 4 g/t (0.116 oz per st). Total tonnage of material, including waste, is estimated at more than 60 Mt (66 million st). The mining plan is a combination open pit and underground operations. The bottom 78 m (255 ft) will be mined by the underground panel-caving method. The open pit was designed as a contractor operation up to the expected milling stage or the point of sustained ore production. The pit was designed to avoid disturbance of US Highway 85 near Lead, SD. In 1983, the South Dakota Board of Minerals and Environment approved the mining and reclamation plan. Test mining began in the north of the Open Cut using open pit methods. Upon completion of the test pit, Homestake Mining's board of directors approved an expanded mine plan. They committed an additional $27.1 million to prestrip the ore body that is expected to yield 23 t (750,000 oz) of gold. Project life is estimated at 15 years. Exploration program In early 1980, 10 diamond drill holes were drilled from the surface in the vicinity of the east side of the Open Cut. The reserves delineated by that drilling were too small to justify their development. A continuation of this study attempted to quantify the tonnage remaining in the bottom of the Open Cut in the crushed remnants of old stope-and-crown pillars. This was originally thought to be minable by improved drawhole methods using highly mechanized procedures. By early 1981, however, thinking turned toward surface mining methods. The effort to quantify minable ore tonnage ultimately involved drilling 385 reverse-circulation rotary drill holes. These were drilled from August 1981 to March 1983 in several groups of holes. Each group, or drilling program, had a slightly different immediate goal or purpose. The holes were drilled to various depths using truck-mounted Drill Tech 40 drills with doublewalled 76 mm (3 in.) pipe with 134 mm (5.25 in.) three-cone rotary bits. Initially, wet drilling was employed using a cyclone collection system. Since cutting recovery was not as high as it should have been, all subsequent drilling was dry. The cuttings were collected and deposited by way of a cyclone into the sample bag. The pickup for the cuttings using the three-cone bits was about 50 mm (2 in.) above the bottom of the hole. Overall cutting recovery for the drilling program was estimated at 75%. Samples were taken on each 1.5 m (5 ft) of hole drilled. Each sample was split into three 48-g (1-2/3 assay ton) charges. The accepted value was the straight average of the three charges. Because of the known "nugget effect," assays were nearly impossible to duplicate. Therefore, to validate the regular assays, a series of screen fire assays were run. Based on this method of assays and checks, it was concluded that 10% more ounces would be produced than indicated by mine grade. Test pit The northernmost portion of the mine as planned is known as the Terraville test pit. This portion was mined ahead of the rest and separately. It provided answers to questions on slope stability, reserves correlation, mill recoveries, mining costs, and surface mining conditions in various weather and ground conditions since many boulders and much timber were expected. The mining plan for this portion of the pit was successful. More ore was mined than was expected. Mixing of Open Cut ore with underground ore in the mill feed was successful. Impact on the surrounding communities

Jan 10, 1987

By Francesco Vegliò, Luigi Toro, Francesca Pagnanelli

"Different hydrometallurgical processes have been studied in order to recover manganese(II) from oxidised minerals such as MnO2 (Vegliò and Toro, 1994). An innovative acid reductive leaching carried out in soft experimental conditions was here considered using agro-industrial wastes containing carbohydrates as reducing agents (Vegliò et al., 1998).The leaching process was investigated from a kinetic and equilibrium point of view in order to optimize the experimental conditions and obtain high purity and concentrated MnSO4 solutions.The overall leaching process (not considering the complex network of intermediate oxidation reactions of the carbohydrates in hot sulphuric acid medium (Vegliò and Toro, 1994)) can be described by the following reaction:24 MnO2 + C12H22O11 + 48 H 24 Mn2+ + 12 CO2 + 35 H2O (1)A Shrinking Core Model (SCM) was modified by a variable activation energy term to take into account both the variable reagent concentrations and the reaction rate change with respect to the manganese dioxide conversion. The influence of the particle size in the kinetic model is discussed with the support of SEM analysis and BET surface measurements before and after leaching.Manganese extraction yield was maximised (170-190 g/L) using appropriate carbohydrates and acid excesses, while impurity concentrations were kept low (Fe<10ppm and Ca<300ppm) pre-treating the ores, using hydroalcoholic leaching medium and different combinations of down-stream processes. In particular precipitation, solvent extraction and adsorption onto active carbon were tested to eliminate Fe and Ca from MnSO4 solutions."

Jan 1, 2003

By John McNeil

Mr. President, and Members of the Rocky Mountain Coal-Mining Institute-Gentlemen : I appreciate the distinction of addressing this representative body of men upon a subject that lies so close to the heart of each one of us, and which is one of the principal objects of our gathering here today, in this beautiful city-so beautiful, with its grand and glorious mountains looking down upon us, that its charm makes us almost forget the men we left toiling "underneath the ground." But that object-the safeguarding of our coal-miners, who spend the greater part of their lives delving in the bowels of the earth-is the cause of our gathering from the "rock-ribbed" States of Utah, Wyoming, New Mexico, and Colorado. And, as I look about me, my eye lights on the face of many an old-time friend- on some with whom I have walked for more than thirty years; so, whatever the merit of this little talk of mine, it cannot be said that it was made by a "tenderfoot." You must not for a moment think that I shall attempt the impossible task of completely covering so comprehensive a subject as &apos;(Accidents in Coal Mines,&apos; and take much more time than has been allotted me, or would be advisable for me to consume. So I shall confine myself, as briefly as possible, to some of the most common causes of accidents, and the possible means by which these disasters may be diminished. For a great many years the cause of mine accidents and their prevention have been the subject of grave thought and investigation by both national and state governments. As early as 1835 Great Britain appointed a royal commission of talented men, possessing special knowledge in the conduct of coal- mining, also eminent authorities in science and its application, to search into these matters. Since 1835 there has been a succession of such commissions of research, at frequent intervals, in all countries wherever coal has

Jan 1, 1913

By Zhu Tonghao

A method of calculating anti-slide pile, sheet pile, underground diaphragm and structure with anchors etc. is proposeed in the paper. The effect of the various layers of soil, anchors and bracings etc. on laterally loaded structures may be considered in the model. In the analysis the structure is divided into a series of elements. The transfer matrices of both deformation and internal force are established for each element. According to continuous condition neighbouring element should be connected. Thus the deformation and internal force of each element can be found out in conbination with boundary conditions. The method has a wider adaptability and it can be applicable to a great variety of the analysis of interaction between various structure and soil. If parameters in model are selected properly, the computed results would be in good agreement with the measured data.

Jan 1, 1991

By J G. Webster-Brown, K L. Brown

The Waihi Region is host to many low sulphidation epithermal Au-Ag deposits. The Golden Cross mine located at the head of the Waitekauri River, eight kilometres NW of Waihi, was a gold mining operation that placed significant emphasis on environmental management. An assessment of the influence of this mining project on stream sediment geochemistry (Fe, Mn, As, Cu, Pb, Zn, Cr, Cd, Ni, Ag and Se) in the Waitekauri Catchment has been made. Effective waste management during the mine operation appears to have prevented contamination of stream sediment. Trace metal concentrations in the Waitekauri Catchment sediment have generally decreased since 1987, and are currently mainly below the ANZECC (2000) sediment quality guidelines. However, elevated As levels were recorded in the Upper Waitekauri River and Battery Stream, exceeding guideline values. Elevated levels of Cu, Pb, Zn and Cd were found in the Huanui Stream, a tributary of the lower Waitekauri River. This reflects the influence of past mining operations in the valley, as well as natural weathering of hydrothermally altered Coromandel Group andesite. At a number of sites, Mn concentrations also exceeded sediment quality guidelines, and this may be derived from the remediated Golden Cross mine site.

Jan 1, 2003

By Natalie J. Shackleton, Deryck de Vaux, Cyril T. O’Connor, Vratislav Malysiak

"The major losses of PGM and base metals in the beneficiation of platinum group deposits occur during the separation of gangue from the value minerals by selective flotation. A number of studies have shown that this negative impact on flotation is due to surface passivation, caused by various ions that may originate from the external water supply or, as is likely in the majority of cases, from the oxidation of the mineral surfaces and the grinding media. The objective of the study was to investigate the effect surface passivation and inadvertent activation have on flotation and how this can be managed so as to increase the separation of pentlandite and pyroxene. The aim was to minimise the percentage pyroxene reporting to the concentrate and simultaneously maximise the pentlandite recovery. The testwork incorporates the addition of an activator (copper sulphate), a complexing agent, such as DETA (diethylenetriamine) and a dispersant (polyphosphate) at pH 6 and pH 9 in an attempt to alleviate the surface passivation of pentlandite and inadvertent activation of pyroxene. Both synthetic minerals and plant ores were studied in order to determine the effect surface passivation and inadvertent activation have on mineral surface alteration and floatability. Zeta potential determinations, microflotation, ToF-SIMS (Time of Flight Secondary Ion Mass Spectrometry) analyses, laboratory batch flotation tests and continuous flotation testwork were used as tools to study the surface alteration and/or floatability.Zeta potential determinations and ToF-SIMS analyses showed that copper adsorption is non-selective. Both pentlandite and pyroxene become copper (II)-activated in the presence of copper sulphate and subsequently, in the presence of xanthate, adsorption of the collector will occur onto copper activated mineral surfaces. Zeta potential determinations also showed an alteration of the surface charge in the presence of polyphosphate, thereby inhibiting surface passivation of sulphides by slime coatings due to surface repulsion."

Jan 1, 2003

By A. v. E. Conradie, I. Nieuwoudt

Comminution and flotation circuits are frequently perturbed by disturbances, such as feed particle size variations, ore hardness and varying mineral liberation, which can have a significant impact on the recoveries and grades. Although advanced control strategies can neutralize many of these disturbances, few such systems have been implemented at present. One reason is that it is only recently that the requisite sensor systems have been developed and used to control froth flotation systems. Another is owed to the complexity of these non-linear interactive systems. In this paper, a plant-wide control strategy is considered, wherein both unit operations have a single overall control objective. The automated design of the controller is based on an advanced evolutionary algorithm viz., Symbiotic, Memetic Neuro-Evolution (SMNE), for developing neural network controllers in a reinforcement learning framework. A rigorous phenomenological comminution and flotation model was used to develop suitable neurocontrollers, which used all possible sensor inputs and available manipulated variables. The neurocontroller managed to identify optimal or near-optimal operating conditions consistently and showed robust performance in the presence of significant disturbances. The results suggest that evolutionary reinforcement learning offers a very competitive approach towards the development of integrated non-linear controllers for mineral processing plants. Keywords: neural networks, control, flotation, comminution, evolutionary reinforcement learning

Jan 1, 2003

By Onuralp Yücel, Süheyla Aydin, Erçin Ersundu

Turkish iron and steel sector, the base of which was established in the 1930?s, plays an important role in the industrialization and development of the country?s economy. In Türkiye this sector is the major consumer of ferroalloys. There had been a great improvement in Turkish Iron and Steel industry, especially after the 1980?sand as a result, 20.9 million tons of yearly crude steel production placed Türkiye 11th in the global steel output and 3rd in Europe. 15 % of steel produced in Türkiye is flat products, while the long products make the rest. The product composition and the general characteristics of steel production process led to an increase in ferroalloy consumption. Domestically consumed ferroalloys are especially ferromanganese, silicomanganese, and ferrosilicon. As of today, ferroalloy production capacity of Türkiye is 173,800 tons/year; 161,500 tons of which is ferrochrome with high and low carbon grades, 7,300 tons of ferrosilicochrome and the rest is ferrosilicon (5,000 tons/year). Türkiye is one of leading ferrochrome producers in the world considering the above mentioned production figures. However, this production is mainly exported since Türkiye?s stainless steel production level is modest requiring low amounts of ferrochrome. The products of iron and steel industry in Türkiye require large quantities of other ferroalloys, which make Türkiye a major importer and exporter of ferroalloys. The aim of this work is to present production, consumption, import and export quantities of: ferrochrome, ferromanganese, ferrosilicon, ferromolybdenum, ferrotungsten, ferrotitanium and ferrovanadium of Türkiye, between 1990 and 2006.

Jan 1, 2007

By Hong Nguen Vu, Pavla Ovcarí, Peter Fecko, Barbara Tora

"The goal of the work was verification of bacterial leaching on the samples of black coal. From the results obtained it was clear that the coal is very well leached by Thiobacillus ferrooxidans and this technology can be used for coal desulphurization. A leaching time of one month is required, to remove 65% of total sulphur and 85% of pyritic sulphur.Microscopic evaluation of samples from Jaworzno showed, that it should be classed as a coal with low coalification, probably from black coal hemiphase. Macerals of the liptinite group were well distinguishable; they were of a dark brown colour. Evidence of coal mass oxidation was apparent on the fresh sample; in the test samples (during bacterial leaching) small grains were oxidised."

Jan 1, 2003