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By C. M. Diaz

The chemistry of the main unit processes in nickel extractive pyrometallurgy is reviewed. Key re1a ions between smelter feed composition and process selection are discussed, with particular reference to operating conditions, energy requirements and products. The paper a1 so includes a brief discussion of current nickel smelters, based on the results of a recent survey carried out by TMS.

Jan 1, 1988

By Cavallaro. J. A.

This report presents the results of a washability study of 455 raw coal channel samples with special emphasis on sulfur reduction. These raw coals contained on the average 14.0 percent ash, 1.91 percent pyritic sulfur, and 3.02 percent total sulfur. The complete washability data are presented for each sample processed. A statistical evaluation is included for the coalbeds from which more than 10 samples were collected and for the geographical coal producing regions. A graphical summation is presented for the coal producing regions and selected coalbeds. Finally a similar statistical evaluation is included showing composited data interpolated at Btu recovery levels of 50, 60, 70, 80, 90, and 100 percent. Graphical summations are presented for the various coal producing regions. Generally, significant sulfur reduction is achieved if the coals are crushed to a finer size and the higher specific gravity increments are removed. If a 50-percent Btu recovery was acceptable, then 32 percent of the samples tested could be upgraded to meet the current Environmental Protection Agency (EPA) standard of 1.2 pounds of S02 emission per million (MM) Btu when crushed to 14-mesh top size and separated gravimetrically.

Jan 1, 1976

By Miguel Reyes, Chenming Zhou, MATTHEW GIRMAN

Electromagnetic energy emitted from electronic devices has been known to interfere with other electronic systems, hindering their ability to function properly. Mines have many electronic devices critical to the health and safety of mine workers that could be negatively affected by electromagnetic interference (EMI). To ensure that devices are electromagnetically compatible, tests must first be conducted to measure emissions and check for immunity. There are many standards available across multiple industries that prescribe emission limits and test methods for electronic devices. Due to the unique environment of an underground mine, it may not be enough to simply adopt a standard from another industry to mining. A literature review has been conducted, and an overview of EMI standards in other industries will be provided in this paper. Also, an example of how a standard can be applied to mining equipment is presented. Finally, recommendations on standards which could potentially be applied to mining will also be included. This work will inform the mining industry of EMI standards in other industries so that mine workers and technology manufacturers have guidance of the steps that can be taken to investigate and reduce the impact of electromagnetic interference and potentially work toward electromagnetic compatibility. The findings and research involved in this effort can also be used to explore the need to develop mining-specific EMI recommendations and standards.

Nov 25, 2021

By Gabriel Esterhuizen

Observations of pillar conditions in limestone mines showed that the presence of weak bands in the limestone can result in pillar damage at stresses that are lower than one would otherwise expect. The objective of this National Institute for Occupational Safety and Health study was to investigate the mechanism of failure caused by the presence of weak bands by using a series of numerical models based on realistic physical properties. The effect of the weak bands on pillar strength was also investigated by developing a series of pillar models with different width-to-height ratios and determining their strength by simulating a servo-controlled loading condition. The material properties of the bands and the limestone were varied and their effects on pillar strength were determined. Model results demonstrated failure development similar to the pillars observed in the field. The weak bands were seen to develop tensile stresses in the limestone as they extrude under increasing stress. The limestone fails in tension at a much lower stress than its expected uniaxial compressive strength. The results showed the load bearing capacity of the pillars can be reduced significantly by the presence of multiple thin weak bands. The degree of strength reduction is largely dependent on the compressive strength, the frictional resistance and the thickness of the weak bands. Single weak bands do not affect pillars as severely as multiple bands. However, the model results show that a single thick weak band, which comprises more than about 2 percent of the pillar height, can cause a significant reduction in pillar strength. The weakening effect of the bands become less severe as the pillar width-to-height ratio is increased. Field observation of spalling and failure associated with weak bands in limestone pillars show that the failure mechanism in the models resembles the observed failure. The model results provide insight into the important factors affecting pillar strength in the presence of weak banded materials.

Jan 1, 2007

By M. A. Verhaege, Stanislav S. Naboychenko, Vladimir I. Skorohodov, Olga Yu. Goriaeva

A new technology for the processing of secondary raw materials containing precious and Platinum Group Metals (PGMs) has been designed at the Laboratory of Heavy Metals at USTU. The technology is based on hydrometallurgical processing of the materials followed by sorption separation of the PGMs from the leach solution. Different versions of the technology can be realised depending on the type of processed material but the fundamentals are similar. Some parts of the technology can easily be integrated into existing flowsheets. The stage of sorption removal of platinum and palladium was tested on the site of the Joint Stock Company (JSC) "Uralelectromed" on pilot plant scale. A process was developed to obtain fine gold, silver, platinum and palladium. No waste is produced because all solutions are recycled. There are no gas emissions. Selective sorption of platinum and palladium from silver-containing solutions is possible even if the concentration ratio of silver to PGMs is one thousand to one. Sorption behaviour of the PGMs as a function of the bulk metal concentrations was studied. Recovery of 90-95% of platinum and 70-80% of palladium is possible.

Jan 1, 2000

Sequential and evolutionary changes through time are recognizable in many, perhaps most major families of ore deposits and their geological environments. These changes are additional useful indicators of the evolutionary history of the earth and its tectonic processes. They are important in mineral exploration because they involve consideration of time as a fourth dimension, thereby indicating the most favorable ages, rather than types of rock for investigation. Many of the changes are analogous to those recognized in faunal evolution. Some primitive, unspecialized types of ore deposits occur nearly unchanged through rocks of widely differing age. Others diversify into several, more specialized variants, whereas still others become extinct. The place of these is taken by new, younger types, some of which undergo sudden proliferations and later diversifications of their own. In Archean greenstone belts irrlportant iron, nickel, gold, and base metal deposits occur co-regionally, but in different stratigraphic positions in the same, thick volcano-sedimentary successions. Here their close temporal and spatial associations suggest common genetic exhalative hydrothermal processes. The massive base metal sulfide family of ore deposits provides an excellent example of evolutionary changes, exhibiting distinct variations through both time and space. Deposits belonging to this family span the entire range of time, occurring in rocks of ancient Archean to Recent age, and specific types within the family also span the entire range of spatial environments from ensimatic to ensialic. Moreover there are possible evolutionary metallogenic links between certain types of massive base metal sulfide deposits and other important base metal ores, noteably Mississippi Valley-type and porphyry copper deposits.

Jan 1, 2013

By W. C. Winegard, A. Galibois, C. J. Beingessner

The effects of solutes on the distribution of two-dimensional configurations of grains in zone-refined tin have been studied. When solutes with partition coefficients (ko) greater than unity are added, three-sided pains become more prevalent and the growth law changes. It is shown by electron-Probe micro-analysis that a solute buildup occurs ahead of a moving grain boundary when ko > 1. It has been found recently1, 2 that solutes with partition coefficients greater than unity have a larger retarding effect on grain growth than solutes with k, less than unity. ko is defined as the ratio of the concentration of solute in the solid to the concentration of solute in the liquid with which the solid is in equilibrium. Niessen and winegard2 have suggested that this effect is probably due to the complex shape changes which occur during the process of grain growth and that no theory based on single boundary motion3-5 can explain the results. They suggested that the dissociation of the unstable fourfold junction was delayed in alloys where ko was greater than 1 because the boundaries at the junction had to move into a region of high solute concentration. If indeed this mechanism were correct, it was felt that not only would the dissociation of fourfold junctions be affected by the solute buildup ahead of the boundaries, but the collapse of three-sided grains would be impaired. These combined effects would naturally lead to a modification in the distribution of the number of sides per grain seen on a two-dimensional section. The present investigation was undertaken to test these hypotheses by examining the grain-growth process in detail. EXPERIMENTS The Distribution of Grain Configurations in Zone-Refined Tin as Seen on a Two-Dimensional Section. Following the method of Bolling and Winegard,6 zone-refined tin was cast into button-shaped specimens and, subsequently, plastically deformed under a drop hammer at room temperature. The resulting flat coin-shaped samples were annealed at 200°C, some for 50 sec and others for 100 sec. The specimens were then examined to determine the distribution of the number of sides per grain, i.e., the num- ber of crystals adjacent to any particular grain in the section. For simplicity, the grains were classified as three-sided, four-sided, and so forth; this concept is schematically illustrated in Fig. 1. As indicated by smith,' it was necessary to examine every grain within an enclosed area to obtain a proper distribution of the relative frequency of each type. The distributions for the two annealing times are illustrated in Fig. 2. The total number of grains examined is also indicated on the figure. It is evi-

Jan 1, 1965

By E. B. Harden, J. H. Harden

The practical use to which topographical models or relief-maps have been put, has within the last few years taken a wider range. They are rapidly coming into favor for other than purely scientific purposes, and their value for illustration and instruction is being more fully appreciated. Topographical maps; representing by contour-curve lines the elevations and depressions of the earth's surface, are now demanded in engineering work of nearly every description, and afford a ready means of bringing out the configuration of the country in a simple manner. A beautiful example of recent topographical mapping is seen in the seventeen sheets just issued by the Geological Survey of New Jersey. By reason of the inability of unskilled persons to understand the nature of a topographical map, it is sometimes necessary to con struct the same in relief, with the rivers, canals, railroads, etc., delin eated upon it. With the aid of such a map, problems in engineer ing science which would otherwise require expert assistance to explain them, are reduced to a simple and understandable form. Relief-maps are also of value to the geologist in working out the geological structure. To the instructor they present the most ready and efficient means of imparting clear and accurate knowledge of topography and kindred subjects. To the lawyer they are invalua ble in enabling him to bring into the court-room a representation of a part of the country with all its features accurately shown, to ex plain to the court and jury the special points about which litigation is pending and which would otherwise require long and laborious description. The application of the topographical map to business purposes is shown in a relief constructed by the writers for the Cumberland Valley Railroad Company and used by that company in the various ways of calling attention to the desirability of its route. This model is based partly on actual survey and partly on sketch topography. The horizontal scale is ,%, the vertical 1/19,200 of

Jan 1, 1888

By Mike D. Riley, Alan V. Bell, Ernest K. Yanful

Acid mine drainage (AMD) research under the MEND program has been ongoing since 1988 at the Heath Steele Mines waste rock piles including sulphide material, outside Newcastle, NB. In 1989 approximately 10,000 mt of waste rock was placed on a prepared sand base with an underlying impermeable membrane. The waste rock pile was heavily instrumented for measuring oxygen concentrations and temperatures. In September 1991, a composite soil cover designed for the Heath Steele climatic conditions, using local soils, was placed over the pile, creating a totally enclosed system. Moisture content and oxygen probes were installed within the composite soil cover to monitor changes within the soils over time, while two large-size lysimeters were installed below the cover to monitor the hydraulic conductivity of the cover. The waste rock site has been monitored on a monthly basis since installation of the cover, for performance of both cover and waste rock. The monitoring shows very clearly that the placement of the composite soil cover has had a major impact on the generation of AMD. Major reductions in temperature and oxygen concentrations within the waste rock pile indicate that the cover has significantly inhibited the oxidation reaction that generates the AMD. Performance data have shown that the cover has maintained its integrity under the climatic conditions of the area.

Jan 1, 1995

By Orlando Rojas, Javier Pizarro, Romke Kuyvenhoven, Francisco Soto

"The concept of geometallurgy has been extensively mentioned and used in the mining industry in the past years. However, each mining firm has a different understanding of what geometallurgy means, and its actual value varies significantly from site to site. Even in the case of properly constructed geometallurgical models, it is fairly common to observe a sub-utilization of the model in the actual operation, because of its low production forecasting capability on the short term. This disconnect between the geometallurgical model and operations is typically caused by a lack of tuning between the original model and the actual plant operation. Also, the absence of procedures and other standards for reconciliation, affects the confidence and the predictive quality of the model. The geometallurgical model should consist of three different levels: (I) adequate capture of information, (II) data analysis and modelling, and (III) development of the block model. Once the geometallurgical in-situ model is finalized, a process model should be developed of the plant at industrial scale, in order to scale up the in-situ geometallurgical parameters from their base or standard condition, to the actual operating reality of the plant. Finally, the stage of reconciliation will close this process, assuring that any deviation between the geometallurgical model and the actual plant operation is not due to lack of tuning, but due to operational issues such as unattended maintenance requirements or poor process control in the operation. The methodology as described in this paper has been applied at several large mining sites in Chile. The paper presents the characteristics of the proposed methodology, and quantitatively describes its benefits with examples from actual operations.INTRODUCTIONIt probably is fair to say that geometallurgy became widely used in greenfield projects in the Andes region during the mining boom of the 90’s, when massive orebodies were studied and developed, and upfront metallurgical characterisation proved its use for accurate economic evaluation including estimates of plant throughput, energy consumption, final product quality and overall recovery. A few examples of such greenfield studies for concentrator plants in the 90’s are Minera Los Pelambres (Antofagasta Minerals, Chile), Minera Escondida, Laguna Seca (BHP Billiton, Chile), and Rio Blanco (then Montterrico Metals, Peru). Large size hydrometallurgical operations such as Cerro Colorado, Quebrada Blanca and Lomas Bayas (all in Chile), also recognised early on the importance and value of relating ore mineralogy, geological characterisation and metallurgical behaviour."

Jan 1, 2016

By D. A. Dahlstrom

D. R. Lyons (Republic Steel Corp., Cleveland)— Some tests using wet tables conducted by an operating company to determine the effect of table-water density on the quality of the washed coal should be of interest. The only variable during the testing period was the percentage of solids in the table water. Table operating data are shown in Table XV. The ash content of the washed coal remained constant or nearly so, as the percentage of solids varied while the sulphur content of the washed coal decreased as the percentage of solids increased.

Jan 1, 1952

[ ] DISCUSSION F A LORIA*-The method of testing gun steel for resistance to surface cracking described in this paper was restricted to the examination of small, rod-shaped specimens The writer would like to point out the importance of other factors in producing defects in forged and bored gun tubes which would not be apparent in this investigation because of the nature of )he test Actual section size would accentuate the possibility of internal wall (bore) defects arising from unequal expansion between the internal and external wall surfaces on firing, resulting in internal tearing Checks and tears on the inside walls arise from internal tensions and nonuniformity on cooling, but the internal tearing can be reduced by using alloys of low expansion and of good thermal conductivity so as to reduce the difference between the outer and inner wall surfaces Also, the possibility of the location of inclusion segregates within a machined gun tube becomes more likely than in a small test specimen The effect of these nonmetallics on gun life and performance is evident when one realizes that the inclusions are soft yet brittle They reduce the amount of plastic deformation which can take place before cohesive failure occurs Once localized fracture has occurred at the position of a chain of these inclusions, a sharp notch (crack) is formed which produces stress conditions more favorable to cohesive failure than to plastic deformation These cracks aid erosion by providing channelways for the explosive gases, eventually leading to the tearing out or spalling of blocks of metal Oxidation of the surface may be partly responsible for the change in the surface of gun steel during firing observed by the author The appearance of burn on the surface is an indication that high temperatures were reached on firing, resulting in a slight oxidation of the surface Since the color of the oxidized film depends on both temperature and time, a higher temperature is required for a given color to form when it is caused by explosive heat, which acts for only an extremely short time at a given spot, than when it is caused by ordinary tempering The cross section of the gun steel specimen, Fig 16, illustrates that the repeated firing temperatures were high enough to cause

Jan 1, 1948

By Dale S. Preece, J Paul Tidman, Stephen H. Chung

A discrete element computer program named DMC-BLAST (Distinct Motion code) has been under development since. 1987 for modeling rock blasting (Preece & Taylor, 1989). This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in two dimensions (2-D). DMC-BLAST calculations compare favorably with data from actual bench blasts (Preece et al, 1993).

Jan 1, 1998

By M D. Winning

The historical development of the elemental sulphur recovery industry in Western Canada is reviewed for the period 1952 to 1965. A brief technical description of a typical modified Claus sulphur recovery unit is presented. Some predictions are made concerning the future of the elemental sulphur recovery industry in Western Canada. THERE are evidences of sulphur or its compounds having been used for religious and medicinal purposes as far back as we have a recorded knowledge of history. As typical examples, sulphur was burned as a sort of inverse incense to drive away evil spirits at religious festivals, sulphur ointments were used by the early Egyptians to cure eye ailments, and hot sulphur-spring water was used as a cure for a variety of ailments. Thermopyle was called "Hot Gates" be-cause of its fame as a spa as well as a mountain pass. The Romans discovered the sulphur deposits in Sicily and mixed sulphur with bitumen for incendiaries; and, of course, anyone familiar with the travels of Marco Polo knows about the Chinese development of gunpowder, which contains sulphur. In some aspects things haven't changed much today. We still use sulphur-bearing ointments, and we still use the hot sulphur springs such as the one at Banff in Western

Jan 1, 1965

By Igor Rojkovic

The most important uranium mineralization in the Western Carpathians occurs in the Permian rocks. Low grade stratiform uranium mineralization was formed during the Permian due to adsorbtion and reduction by organic matter, titanium oxides, iron hydroxides, pyrite and clay minerals. During the Alpine orogeny uranium (± molybdenum and copper) remobilized stratabound ores were formed. Dominant ore minerals are uraninite, U-Ti oxides, molybdenite, pyrite and chalcopyrite Two generations of ore minerals are reflected by their textures and chemical composition.

Jan 1, 1995

By M. E. Smith

Waste rock dumps, tailings impoundments and spent leach heaps are common features at mine sites. Many of these waste disposal facilities contain sulfide-rich minerals, which generate acid mine drainage (AMD) when they oxidize. Control of AMD can be achieved by removing one or more of the three essential components in the acid-generating process (sulfides, air, or water). One AMD prevention measure is to cap the waste with an engineered cover system to minimize the infiltration of water and diffusion of air into the system. Possible cover designs include: ? Earthen ?store-and-release? covers (also known as evapotranspiration (ET) or water balance covers), including capillary barriers. These covers require climate conditions where there is both modest to little rainfall and significantly greater evapotranspiration than precipitation, both annually and seasonally. ? Low-permeability compacted clay liners (CCLs) employing fine-grained soils typically compacted at wet of optimum water content. ? Geosynthetic composite covers, comprised of a geomembrane liner placed over and in direct contact with either a CCL or a geosynthetic clay liner (GCL). These systems have been commonly used for base liners for leach pads as well as covers and base liners at municipal solid waste (MSW) landfills in the US for more than 20 years. Comparisons of these different cover systems, both in terms of performance and cost, are presented later in this paper. First, however, a review of the typical mine closure approaches, and the possible rationale behind them, is warranted.

Feb 27, 2013

By Paul Pugsley

The EMSpec sensor employs the principle of measuring the complex impedance of the target steel over a range of frequencies these impedance values in turn varies with transformation fraction of the steel. A full scale implementation of the Real Time Transformation Monitoring has been installed at a quality large European steel producer to show the benefits of such a system. A total of three EMSpec sensor heads have been installed between the exit Finishing Mill and the Down Coiler on a HSM. For the successful production of Dual Phase, TRIP and TWIP steels increased control of the cooling regime is demanded; the use of surface temperature measurements alone cannot guarantee to achieve the desired mechanical properties. The EMSpec sensor, which is engineered to withstand this harsh environment, in real time directly measures the percentage transformation of the steel in the cooling area, typically in the accelerated water cooling zone. Using the information from the sensors integrated into the mill model enhances the models ability to predict the transformation profile.

Aug 17, 2017

By H. J. Siriwardane

This paper presents results from three case studies involving longwall mine panels at which the measured ground movements were compared with the numerical model predictions based on the finite element method. A new approach called the "displacement approach" was used in this study. The general concept of this method is based on the assumption that total roof collapse occurs behind the mine face as it advances. This assumption appears to be true for almost all longwall mining conditions. The prediction based on the numerical model appears to compare well with the measurements.

Jan 1, 1988

By P. L. Richard

An open pit a mine can be thought of as a business unit, with capital, operating and maintenance costs that exceed those of many large business enterprises. Truck-and-shovel operations have an inherent ?looseness? to them, unlike manufacturing or processing operations where production components are tightly coupled (through conveyors, material flow in pipes, assembly lines, and so on). Effective monitoring and control of truck-and-shovel operations requires a combination of both information systems and performance management. Production monitoring systems can impact operations at three levels: minute-by-minute decisions during the shift, procedures, and policies. The technology of production monitoring ranges from real-time data collection to manual entry of time card data into a computer. Time card information is too coarse to effectively manage a multi-million dollar fleet of mobile equipment, so a higher level of production monitoring is required. People issues affect whether the implementation will be a success or a disappointment. Considerations that affect the people issues are discussed, including common obstacles, and key success factors. A balanced scorecard approach must be used, since uni-dimensional measures of performance like tons produced give no indication of whether the production was achieved at the expense of another factor.

May 1, 2004

By P. L. Richard

An open pit a mine can be thought of as a business unit, with capital, operating and maintenance costs that exceed those of many large business enterprises. Truck-and-shovel operations have an inherent “looseness” to them, unlike manufacturing or processing operations where production components are tightly coupled (through conveyors, material flow in pipes, assembly lines, and so on). Effective monitoring and control of truck-and-shovel operations requires a combination of both information systems and performance management. Production monitoring systems can impact operations at three levels: minute-byminute decisions during the shift, procedures, and policies. The technology of production monitoring ranges from real-time data collection to manual entry of time card data into a computer. Time card information is too coarse to effectively manage a multi-million dollar fleet of mobile equipment, so a higher level of production monitoring is required. People issues affect whether the implementation will be a success or a disappointment. Considerations that affect the people issues are discussed, including common obstacles, and key success factors. A balanced scorecard approach must be used, since uni-dimensional measures of performance like tons produced give no indication of whether the production was achieved at the expense of another factor.

Jan 1, 2004