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By J. Walden, S. Rhoades, R. E. Miller, R. Gibbs, P. Boman

Accelerometers and pressure transducers mounted in suspension components can be used to monitor the ride of haulage trucks. Presently, it is difficult to tell what caused a jolt to the truck using either pressure or acceleration data alone. When information from a Global Positioning System is recorded at the same time as shock pressures or acceleration data, then the exact location of an event can be determined. Mine management can then determine what caused the jolt to the truck.

Jan 1, 1999

By H. C. Seeber

When considering all the aspects of a viable mine plan, it is important to estimate the accurate cost of mine ventilation, which varies as a function of airway dimensions, fan selection and ventilation network. Optimization of the overall elements of ventilation design can lead to very significant cost savings when capital and operating cost savings are considered in combination. This paper will describe a methodology, whereby ventilation costs can be minimized by optimizing the ventilation aspects of mine design and fan selection, by providing a brief description on ventilation theory and the factors which affect ventilation operating and capital costs.

Jan 1, 2002

By R. N. Gow

The presence of enargite (Cu3AsS4) is problematic in gold processing because it is environmentally hazardous due to its arsenic content but also because it is double refractory causing both cyanide and oxygen consumption to increase. Selective leaching and treatment of the arsenic would prove advantageous prior to applying conventional gold leaching methods. The reactivity of enargite samples from Butte, Montana and Quiruvilca, Peru were spectroelectrochemically studied under alkaline conditions, pH range of 8-13, using Raman spectroscopy and cyclic voltammetry. Raman spectra of the surface were collected during and after voltammograms were potentially cycled in order to determine and compare surface species against theoretical EH-pH diagrams determined from mass-balanced thermodynamic calculations using StabCal software. Under slightly oxidizing conditions, covellite (CuS) peaks were found in a short matter of time, above ~100mV vs SHE for pH 9-13, suggesting arsenic leaching specifically occurred. At longer conditioning times, elemental sulfur was observed and tended to passivate the surface. The presence of sulfur suggests that copper was eventually leached. By operating above pH 12, under slightly reducing conditions near -300mV vs SHE, arsenic can be selectively leached as thioarsenate (AsS43-) or thiosulfate (AsO43-) without sulfur formation.

Feb 27, 2013

By Tracy Brettmann

Equipment ? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 2004

By Yemi Akinkugbe

Underground coal mining under massive sandstone can present significant challenges if the roof behavior is not well understood. This paper presents a classic cantilever bending/flexing behavior of a longwall tailgate roof caused by the weighting of structurally massive sandstone strata. Nineteen crosscuts of a longwall tailgate under massive sandstone were instrumented with position transducers connected to a data-logger to monitor roof convergence as the longwall face approached. During the monitoring program, an unusual tailgate roof divergence (uplift) was recorded. This roof behavior contradicts expected norm of roof convergence when the longwall is influenced by periodic weighting. The recorded roof movement data indicated that the roof divergence started well ahead of the longwall face. The most inby position transducer started recording progressive roof divergence when the longwall face was approximately 643 feet away. Very gradual roof convergence did not begin until the longwall face got to within 300 feet of the transducer. Recording of accelerated convergence only started after a massive caving event with the face within 280 feet of the recording transducer.

Jan 1, 2007

By Eugie Kabwe

Rock bolts are components of tunnel support structures and their efficacy in reinforcement requires the appropriate estimation of the bolt pre-tension. However, cases of ineffective rock bolt application due to loosening are common which leads to the potential failure of the support structures, thus negatively affecting the tunnel stability. The effective employment of pre-tensioned bolt within support structures requires an appropriate installation tension as a result of sufficient bolt head/nut pre-load. Henceforth, this paper presents a load indicator washer (LIW) capable of withstanding assigned static loading as well as provides an appropriate pre-tension. The different LIW breadths are numerically analysed in the finite element code (ABAQUS) to estimate deformation when a designated 60-kN pre-load is applied. The numerical simulation employs a bi-linear isotropic hardening constitutive law governed by the von Mises yield criterion. The simulation also considers the nominal temperature of the nutLIW-rock bolt connection. Therefore, a long-term relaxation effect on bolt pre-tension as a result of stress relaxation is neglected. The compressive force required to achieve the LIW-predetermined deformation is the bolt pre-tension. It is drawn from the simulation results that the 1.5-, 2.0-, 3.0-, 3.5-, and 4.0-mm-thick LIWs are completely flattened when subjected to 28-, 42.5-, 65-, 76-, and 88-kN pre-load respectively.

By J. L. Gillson

Joseph H. Birman (Chairman, Dept. of Geolcgy, Occidental College, Los Angeles, Calif.) Many thanks to J. L. Gillson for so comprehensive a survey of the titanium sand deposits of the world. Over the past two years, the writer studied rather carefully some of the Cretaceous ilmenite deposits in New Mexico and Colorado, including the Sanostee deposit shown in Gillson' s map, Fig. 6. The deposits were geologically mapped and sampled, surveyed by magnetometer, and the Sanostee deposit was drilled. Moat of the genetic interpretations made by Gillson concerning the recent sedimentary ilmenites can be clearly read in the Cre-taceous deposits in New Mexico. The deposits are in marine regressive members of the Mesaverde group. The deposits trend within a few degrees of N 55° W and persistence of this trend through both distance and time (the deposits are in different members of the Mesaverde group) implies that the deposits are offshore bar accumulations. Heavy mineral content ranges from about 10 pct to more than 50 pet. Thicknesses are from 4 ft to as much as 20 ft, widths range from 150 to 600 ft, and lengths range from a few thousand feet to a few miles. All are locally or completely overlain by carbonaceous shale and thin coal. The deposits are strongly altered, and from X-ray diffraction the principal titanium alteration product appears to be anatase. Drilling of the Sanostee deposit shows that the alteration is not related to the present erosion surface but took place at the site of deposition and before burial by the overlying sediments. Iron oxide derived from the alteration cements the grains and is the chief coloring agent in the immediately overlying shales. In the Sanostee deposit, there is virtually no feldspar, the gangue mineral being almost exclusively quartz. Sorting is excellent, but the quartz grains are subangular to angular. Petrographic examination reveals that the angularity is not due to overgrowths. Therefore, short distance transport is implied. The mineralogical composition suggests a low relief granitic terrane as the source area. Feldspar may have been decomposed by weathering at the source, but an alternative preferred by the writer is that each of the deposits represents a long-term concentration site (for example a large sand bar) which was continually being deprived of light minerals by wave action and selective transport. Feldspar may have been mechanically reduced in size more quickly than the quartz, and thus its rate of removal may have exceeded that of quartz. Concentration of heavy minerals would thus occur until the marine regression removed the zone of maximum wave energy from the site. Chemical alteration would then become the most important process until burial by encroaching swamp deposits.

Jan 1, 1961

By F. N. Kissell, C. M. McCulloch, Maurice Deul, J. R. Levine

The methane content of virgin bituminous coalbed can now be measured accurately in the field with exploration core samples from vertical boreholes. The gas content of the coal per unit weight can be used either to design a mine ventilation system or to determine if degasification of the coalbed will be necessary before mining, and to determine the gas resources in the coalbed. The equipment necessary to conduct the test costs less than $50. The gas content of the coal in place in the ground is determined by summing the gas lost from coring, gas measured during desorption, and the residual gas in the coal. Upon removal from the borehole, the core sample is placed in an airtight container and desorbed for several weeks until the desorption rate is below 0.05 cm3/g for 5 consecutive days. The gas lost from the core while it was being cored and the residual gas are estimated by a new graphical method. The amount of gas remaining depends upon whether the coal is friable or blocky. Friability appears to relate to the depth of the sample below the surface, fixed carbon percentage, Hardgrove grindability index, and proximity to tectonic disturbance. Friable coals emit nearly 96 pct of the total gas during desorption whereas a blocky coal emits only 60 pct of its total gas. Coalbeds that are ill defined as to their blocky or friable nature must be tested in the laboratory for unambiguous analysis.

Jan 1, 1975

By S Hapugoda, J R. Manuel, M J. Peterson

Microindentation testing using the square–pyramid–shaped Vickers indenter is a well-established technique to determine the microhardness of minerals and materials. However there is a paucity of published microhardness data from Fe ore samples. It is acknowledged that an iron ore’s particle mineralogy and texture is critical to its processing properties, and it is therefore considered that the microhardness of different mineralogical/textural types may also relate to these properties. Mineral microhardness potentially provides inputs to the modelling of breakage characteristics during comminution, as well as the relationship between mineral chemistry and microhardness, and mineral microporosity and microhardness. Microhardness can be determined as single crystal microhardness, for more coarsely microcrystalline samples, or as ‘aggregate microhardness’ for cryptocrystalline or finely microcrystalline samples.Variations in the texture and mineral chemistry of common Fe ore minerals (eg martite and microplaty hematite, ochreous and vitreous goethite etc) are well established and this study provides microhardness data on different textural forms of Fe (oxyhydr)oxides from a variety of different Fe ore deposits. The data indicated that in general, the mineral grain size, microporosity and texture were the main influences on Fe (oxyhydr)oxide microhardness. There were no apparent systematic variations between microhardness and minor element mineral chemistry, with the possible exception of Al content in goethite (for goethites with Al content >0.5 wt per cent), and for goethite total element contents >90 wt per cent (determined by electron probe microanalysis, EPMA). Higher Al concentrations and lower total element concentrations in goethite EPMA analyses correlated with lower goethite microhardness. Microporosity and grain size were more important than texture to hematite microhardness. Different textural forms of dense hematite (eg martite, recrystallised interlocking hematite and specular hematite) with similar grain size exhibited comparable microhardness. Microhardness values for hematite and hydrohematite with little or no evident microporosity were also similar, whereas more porous forms of martite, microplaty hematite or hydrohematite exhibited lower microhardness.CITATION:Peterson, M J, Manuel, J R and Hapugoda, S, 2017. Microhardness testing of hematite-goethite Fe ores – implications for their textural characterisation and geometallurgy, in Proceedings Iron Ore 2017, pp 319–330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Gaby Steinbach

A novel synthesis is described for the preparation of supported gold catalysts for low-temperature CO oxidation. The novel route is a variation of the inverse co-precipitation method and requires amphoteric metal hydroxides, with zinc and aluminium hydroxides chosen. Catalysts were prepared by inverse co-precipitation (ICPa) and by the novel route (ICPb) and tested for CO oxidation at 60ºC. Preliminary results showed the novel route to be superior to ICPa; the catalysts prepared by ICPb showed higher catalytic activities. The effect on catalytic activity of parameters such as pH, calcination temperature, washing of precursor and calcined catalysts and ageing was investigated. A preparation pH of 9 and a Zn to Al mass ratio of 3 proved to be optimal. It was possible to remove residual chloride by washing thereby enhancing catalyst performance. Ageing and Mg citrate addition were also shown to improve catalyst performance. Characterization of the catalysts revealed that better activities were obtained when the support was more crystalline and had a higher surface area. The presence of carbonate-containing species in the support decreased catalytic activity. 197Au Mössbauer Spectroscopy revealed the presence of Au3+ when catalysts were heat-treated at temperatures of 200ºC and below. Catalysts calcined at 400º had 75% of the gold present as Au0, with the remaining gold present as Au3+.

Oct 1, 2003

By Luiz Alberto dos Santos

Neste trabalho foram usinados CDPs da liga com composição de 50,9 % at de Ni e, em seguida, as amostras foram envelhecidas em temperaturas entre 350-550 ºC, tensões aplicadas de 60 MPa e tempos de 45 e 180 minutos. Além disso, foram realizados também envelhecimento sem aplicação de carga nas mesmas condições de temperatura e tempos para comparação das propriedades, porém acrescentando uma amostra solubilizada a 850ºC durante 1 hora. Posteriormente as amostras foram caracterizadas por DSC para determinação das temperaturas de transformação de fases. Observa-se neste trabalho que o DSC de algumas amostras apresentou tanto no aquecimento quanto no resfriamento dois picos de transformação que pode estar relacionado ao aparecimento da fase R. Além disso, pode ter ocorrido a formação da fase Ni3Ti4, pois ligas com teores acima de 50,6 %at. de Ni são caracterizados pela formação de precipitados ricos em Ni, que pode acarreta na diminuição da concentração de Ni na matriz e aumento da temperatura de transformação. Este trabalho é importante, pois há poucos estudos relacionados com o efeito do envelhecimento sob carga nas propriedades de efeito de memória de forma e superelasticidade da liga NiTi.

Aug 16, 2017

By S. Dessureault, J. Porter, M. Woodhall

Information and communication technology (ICT) is seen as a key source of future productivity improvements in mines. The information technology infrastructure (ITI) necessary to achieve these productivity improvements will come in the form of data integrated from multiple source systems throughout the mining value chain. Two pure approaches are available: supplier-controlled or operations controlled data structures; each strategy has its own advantages and disadvantages. Case studies involving the South African mining industry are used to demonstrate the advantages of using hybrid-controlled data structures. Depending on the level of operational control, new skills are also necessary to be learnt by mining professionals including: information engineering; creating consistent and quality data; and process improvement techniques that use the integrated data for improving the operation.

Jan 1, 2004

By Donald J. Hallbom

"While pipeline hydrotransport is often the most economical way to transport large volumes of mineral concentrate, tailings, or fine ore slurry over long distances, it is in mountainous terrain that pipelining becomes particularly attractive. These areas are often remote, with limited existing infrastructure and few potential users willing to share in the cost of new infrastructure. The rugged terrain makes the construction of railways or roads suitable for haul trucks difficult and expensive. The elevation difference between the mine and the terminal means that the empty trains or haul trucks need to return up-hill, resulting in high fuel costs. With pipelines, this elevation difference may reduce or even eliminate the need for pumping. As a result, numerous pipelines have been built, or are being considered, in mountainous regions around the world including: Tasmania, New Guinea, China, Madagascar, the Rockies of North America, and the Andes of South America. However, there are technical difficulties that need to be overcome in the design and operation of mountain pipelines that do not affect pipelines on more level terrain. This presentation reviews some of these difficulties and methods used to overcome them.INTRODUCTIONPipeline transport of solid-liquid slurry (“hydrotransport”) is an important and cost-effective means of transporting large volumes of solids over long distances, especially from a single supplier to a single user (e.g., a concentrator to a port, a concentrator to a tailings dam, or a coal mine to a power plant). Pipelines are generally found to be more economically attractive than alternate transportation methods (e.g. trucking, rail, conveyors, shipping, or some combination) over the life of a project (Aude et al. 1974).Hydrotransport systems have been built in a variety of terrains, but it is in mountainous regions that pipelining becomes particularly attractive. These regions are often remote and generally do not have existing transportation infrastructure (roads, railways, navigable rivers). There are few potential users (e.g., farmers, other mines, forestry companies, etc.) who may be willing to share in the cost of new infrastructure. The rugged terrain makes the construction and maintenance of railways or all weather roads suitable for large haul trucks difficult and expensive. Mines tend to be higher than the receiving terminal (e.g. a port). This means that the empty trains or haul trucks need to return up-hill, resulting in high fuel costs. With pipelines, this elevation difference may reduce or even eliminate the need for pumping. Pipelines are easier to construct than roads and railroads in these areas for several reasons, including:"

Jan 1, 2006

By Alan J. Lutenegger

Some years ago, a method was developed to incorporate a grout column around square-shaft helical screw-piles and anchors to increase shaft buckling resistance under compression loading. An additional benefit of this grouted shaft is to increase the load capacity in both compression and tension, depending on the geometry of the lead helical section and the soil conditions. Because of the unique construction procedure, the contribution of the shaft to the total capacity has largely been unknown. The behavior of grouted shaft helical anchors in clay was investigated by performing full-scale axial uplift (tension) load tests on a series of anchors installed at the University of Massachusetts Geotechnical Test Site. In order to isolate the contribution of the grouted shaft to the total load capacity, anchors were installed with a wooden dowel connection between the lead helical section and extension sections on three of the four anchors so that only the shaft resistance would be measured during the load tests. The grouted shafts ranged in length from 10 to 30 ft (3 to 9 m). Initial tests were performed approximately 5½ months after installation. Nearly four years after the initial tests were performed, the tests were repeated to evaluate any significant change in capacity with time and/or repeat testing (preshearing). The soil conditions at the site are presented along with the load-displacement curves for both the initial and repeat teats and a discussion of the analysis of the results. Repeat load tests showed an increase in capacity from the initial testing, however the percent increase was not the same for all depths. The results demonstrate that considerable shaft resistance can be developed in clays from the grouted shafts as might be expected. Depending on the L/D ratio of the shaft and the contribution of the lead helical section, at working loads the shaft capacity can dominate the behavior.

Jan 1, 2011

By L. A. Melis, J. W. Rowson

"Cluff Mining operates the Phase II uranium mine and mill at Cluff Lake, northern Saskatchewan. During the Phase I operation, uranium tailings were generated by acid leaching of a gravity concentrate and high-grade ore for uranium recovery. The pre-treatment gravity process, as well as the high-grade nature of the ore, led to a concentration of gold in the tailings which justified the installation of a small circuit to recover the contained gold. The operating circuit consists of tailings repulping, grinding, cyanidation, carbon-in-pulp, gold recovery, and cyanide destruction by acidification, volatilization and re-neutralization. The process is described and typical operating parameters are provided. 1.0 INTRODUCTIONCluff Mining, a Saskatchewan partnership, is owned 20 percent by Saskatchewan Mining Development Corporation (SMDC) and 80 percent by Amok Ltd./Ltee. (Amok), manager and operator of the partnership.The current operation includes the Phase II uranium mining and milling facilities, located at Cluff Lake 700 km north of Saskatoon, capable of processing 300,000 tonnes of ore to produce about 4,000,000 lbs. U308 (1500 tonnes of uranium) per year.The Phase I operation was initially established to process the very high grade ""D"" uranium orebody from 1980 to 1983. The leach tailings from the operation Phase I mill operation were found to contain elevated levels of gold. These high gold values were partially due to the gravity pre-concentration step included in the uranium recovery circuit, and to the naturally high levels of gold associated with the uranium mineralization in the ""D"" orebody."

Jan 1, 1988

By David W. H. Ellis

This presentation will discuss over 2 dozen past, present and future oils sands projects in Alberta. The very early projects as well as the most recent along with the ones that never got off the ground and the ones in production are all included. For each, the following will be given (where known): owners, location, type (mining/SAGD/refinery), production, capital budget, spent to date, status. Some overall impacts will be discussed.

May 1, 2004

By S. M. Pickering

Banks frequently manage large privately owned mineral land trust accounts for estate heirs. The bank has a fiduciary obligation to follow the “Prudent Man Rule”, which requires that trust properties be managed at least as well as a prudent and knowledgeable owner could. However, banks may not have internal staff proficient at mineral property values, lease contracts, royalties, mining practices, etc. This is an opportunity for experienced geologic consultants and certified minerals appraisers to provide needed help. Items valuable to Trust managers may include: 1. Marketing privately owned mineral trust lands to mining or oil & gas firms, assuring competitive offering prices and terms; 2. Negotiating favorable new mineral lease and purchase-option contracts; 3. Monitoring progress of mining, royalty payments, land reclamation, and environmental clean-up work; 4. Balancing future mining income with later industrial, commercial or housing development, timber harvest, etc.; 5. Assuring that Depletion Allowance tax advantage is taken for actual mine royalty payments, but not for annual non-mining lease (rental) income; 6. Appraising in-ground mineral value for bank audits, estate tax valuations, and equitable property division between heirs; and 7. Serving as expert witness, representing the legal interests of the bank, trusts, and the mineral heirs in litigation. Banks do welcome reliable advice which assists them in achieving the “Prudent Man Rule” and improving mineral income to their land Trust accounts.

Jan 1, 2002

By Charles H. Foreman

This paper describing the mining practice of the Hecla and Star mines, both located at Burke, Idaho, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. It is partly a revision of articles by the author appearing in volume 72 of the Transactions of the American Institute of Mining Engineers, published in 1925, and in the June 1928, issue of the American Mining Congress Journal. About 26,000 tons per month of lead ore is produced at the Hecla mine. Costs at the mine are given for the year 1928. Stoping operations in the Star mine have covered such a short period, during which time the abnormal expenses of starting were incurred, that they are not given in this paper.

Jan 1, 1930

By Jan Pru?ka

This paper describes the sheet pile design for the Line C extension from Ládví station to the North of Prague. The first part of the paper describes the geological conditions and structural configuration of the project. Typical cross sections, the description of the construction stages, and monitoring are discussed. The second part of the paper focuses on the sheeting design method. It describes the method of dependent pressures, that is, how the pressures acting upon a structure depend on the deformation. The design process and verification methodology are described in detail with comparison of the results with in-situ monitoring.

Jan 1, 2011

By L. W. Burger

The need to establish and harmonise methodologies to quantify air emissions, atmospheric dispersion and the consequences of air pollutants (especially hexavalent chromium) from the ferrochrome industry became important aspects with the increasing demands for comprehensive impact assessments. The paper includes a synthesis of current knowledge on the following aspects: ? Locally and internationally accepted methodologies for the quantification of chromium emissions, including sampling methods and emission factors; ? A compilation of recognised and accepted air quality sampling and laboratory analysing techniques; and, ? Dispersion modelling and impact assessment tools. Depositing and removing materials from the chromium ore stockpile and wind erosion of exposed stockpiles result in mainly chromite emissions unlikely to contain significant amounts of hexavalent chromium. Pre-treatment processes such as drying, crushing and screening also produces chromium emissions, but mainly as trivalent chromium. The smelting of chromium is the major source of chromium emissions - open furnaces have the highest uncontrolled chromium emissions, followed by semi-closed and closed furnaces, respectively. Based on the current knowledge on emission rates, interim emission factors for particulate, total chromium and hexavalent chromium releases are provided. Ambient sampling and analytical methods to determine environmental exposure of the general public require that hexavalent chromium needs to be quantified in very low concentrations. Suggested sampling and analytical methods for both source characterisation and ambient monitoring are provided. The selection between dispersion models needs to be based on the size of the modelling domain and the complexity of the terrain. The discussion on dispersion models includes the US EPA?s Industrial Source Complex Model (Version 3), the AERMET/AERMOD suite of models and the CALMET/CALPUFF suite of models. Guidelines are also proposed for environmental exposure assessments including cancer and non-cancer health effects.

Jan 1, 2004