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By A. Mazhary, T. Huff

Sensor-based ore sorting technology is a growing area of interest due to lower-grade ore deposits and higher costs of processing, among other reasons. Among the sensors currently utilized in the particle sorting industry, X-Ray Fluorescence (XRF), as the only sensor with elemental analysis capabilities, has always attracted more attention. Currently, the bench-scale amenability tests for this sensor are performed using hand-held XRF analysers. However, this testing method overestimates the performance of the XRF sorter, and therefore, the results from these tests can be misleading and are often mispresented. The work presented here was conducted on a copper mine and investigates how the sensor’s sensitivity to copper deteriorates under different testing methods. This work compares and correlates the results of an Olympus hand-held XRF analyser, static, and dynamic sorter responses with the actual grades of the rocks. The results confirmed that, the sorter response was extremely prone to blind spots. Furthermore, the results demonstrated that although the static sorter’s responses were comparable in terms of rock identification to those of the hand-held XRF analyzer and assays, the accuracy of the dynamic sorter response deteriorated both as a function of grade of the rocks as well as the potential for blind spots. INTRODUCTION Sensor-based sorting technology has been gaining increasing attention even by larger mining corporations as ore grades decrease, deposits get deeper and therefore cost of mining and processing increases. There are various types of sensors that are currently being used in the particle sorting industry such as X-Ray Transmission (XRT), Color, Electromagnetic (EM), Near-Infrared (NIR) and others. However, none of the sensors are capable of identifying and quantifying particles by the elemental content, except for X-Ray Fluorescence (XRF). XRF is a non-destructive, surficial analytical technique used to measure elemental composition of materials. X-ray fluorescence happens when a secondary x-ray (fluorescence) is released after a sample is bombarded by a primary x-ray source. From a sorting perspective, the most common and expected issues that are associated with XRF sorting are lower throughputs compared to other sensors due to particle presentation limitation as well as the need to wash the material before introducing to the sorter. However, one important issue that is mostly neglected is how the amenability tests are performed and how realistic the obtained results are. Current amenability test procedure utilises a handheld XRF analyser (such as an Olympus InnovX, as used in this work) on multiple, generally 4, sides of the rock and uses the average measured grade as a criterion for separation. While this is a widely accepted technique, it fails to consider some important factors such as exposure time and the distance between the sensor and the particle. These factors can significantly affect the sorting outcome.

Jan 1, 2019

In the latter half of 1973 a contract was given to Roberts-Holland Joint Venture for the stripping of the southern exhaust airway.The contract was carried out efficiently and relatively cheaply. It was completed 2 months ahead of schedule.The sinking stage and in particular the drilling jumbo proved to be a success and helped produce an above schedule stripping rate.No major problems were encountered with ground conditions or ventilation. A survey of the shaft showed the diameter to be within the set limits of 5·49 m ± 0·15 m.

Jan 1, 1974

By Michael Rieber

The increase in f.o.b. mine prices of coal from $5/ton to over $18/ton in five years [1] has increased the significance of transportation costs. Coals produced in the vicinity of the consumer bear a much lower transport cost than those produced in the west. This differential may be used for flue gas desulfurization, other cleaning, or further processing of local coals. To the extent that western coals are cheaper to produce and have a lower sulfur content, they offset the locational disadvantage. To the extent that they have a lower heating value, the disadvantage is exercabated. Given the other conditions, an accurate analysis of transport costs will help suggest the location of coal mining and the moue of transport both transport costs and tariffs have risen. Together they have increased delivered coal prices, altered the balance between the use of coal and other fuels, helped to alter the location of mining activity, and put pressure on consumers to examine the cost effectiveness of alternative transport modes. Transportation options for long distance coal movements include rail, barge, pipeline, and EHV transmission lines. A summary of system parameters is shown in Table 2.1. Barge transport, pneumatic and slurry pipelines are discussed elsewhere in this report. Together with EHV, they have been the subject of previous studies [2,3,4]. Slurry pipelines have been shown to be especially useful where rails are not available [2] but the technical problems of dewatering, handling, and utilization of lines [5] remain unresolved. They are discussed in Section 3. Barge transportation depends on the location of the mine and consumer with respect to the waterway system. One drawback of barge shipment is interruptions due to winter, and low or high water conditions. Mine mouth power generation followed by EHV transmission of over 500 miles has been shown to be the most expensive means of delivering an equivalent amount of energy to consumers [2].

Jan 1, 1977

A study of literature on the epidiorite dykes which transgress the Broken Hill lode and its wall rocks reveals a considerable diversity of thought regarding the time of emplacement of such dykes. In this paper it is deduced that the epidiorite dykes were formed at a late stage and were probably post-ore. Detailed mapping, sampling, and correlation of data from over 100 exposures substantiates this deduction. Physical disruption of the epidiorite dykes is indicated and some interaction of the epidiorite and ore at the time of intrusion is inferred.Further petrological study may confirm this.

Jan 1, 1968

By Zajber A, Kulchen R, Letzel D, Weyer A, Schwellenbach J

The search for modem casting plant concepts today focuses more and more on the harmonisation and optimisation of overall concept lines to obtain a continuous quality control and reduce the cost of production (Figure 1). Fin I As far as continuous casting plant concepts are concerned, this specifically requires an optimal adaptation and flexible operation when converting liquid steel into a directly processable product without any in-between treatment. Continuous casters need to fully satisfy the requirements of both the upstream steelmaking facilities as well as the downstream rolling facilities.

Jan 1, 1999

Allis Mineral Systems ARCO Coal Company Buckley Powder Co. CALCO, Inc. Coal Magazine Colowyo Coal Company Continental Conveyor & Equipment Company Crane & Hoist Sales Cummins Southwest, Inc. Energy West Mining Company Paul J. Epley FMC Corporation The Falkirk Mining Company Fleischli Oil Co., Inc. T. J. Gundlach Machine Company Halbach & Braun Harnischfeger Corporation Hemscheidt Corporation Hyatt Regency Beaver Creek Jennmar Corporation Joy Technologies, Inc. K&P Sales Engineers, Inc. Kennametal, Inc. Kerr-McGee Coal Corporation McLanahan Corporation National Coal Association The North American Coal Corporation Northwestern Resources Company Peabody Coal Company Phillips Machine Service, Inc. Pincock, Allen & Holt, Inc. Pittsburg & Midway Coal Mining Co. Roberts & Schaefer Company Rust Tractor Company Salt River Project Santa Fe Pacific Coal Corporation Schroeder Industries Shearson-Lehman Brothers Southern Pacific Transportation Stamler Corporation Trapper Mining Inc. Wagner Equipment Company Western Energy Company Wheeler Machinery Company

Jan 1, 1992

Permian coal seams from the Tomago Coal Measures in the Northern Coalfield, New South Wales, were analysed petrographically and reflectance measurements made for each. Vitrite contents were moderate to high for most of the coals but for two they were very low.The mineral-matter contents were low to moderate by Australian standards. Different profiles of a particular seam could be correlated by petrographic methods.Standard seam profiles were drawn up and from these an idealized Tomago seam sequence was compiled. All the coals were of high-volatile bituminous rank. Their carbon contents, but not thcir reflectances, varied significantly with the quantity of vitrinite present.

Jan 1, 1968

By Noris Costa

La posibilidad de construir presas hechas con los propios relaves que van a ser contenidos posteriormente, es una alternativa común en la minería. Sin embargo, durante el levantamiento histórico de estas estructuras, se identifican diversas rupturas, liberando las masas contenidas en las presas y contaminando el medio ambiente. En este sentido, el presente trabajo señala los geoindicadores como herramientas de monitoreo de presas de relaves -en tanto el estudio de estas características ha posibilitado discusiones al respecto de la seguridad de estas estructuras, así como propuestas de medidas de control.

Sep 9, 2007

By Prosper Lamothe

El presente texto describe la metodología ad-hoc para evaluar proyectos de Inversión estratégicos a través de la flexibilidad y la teoría de opciones reales. La clave de dicho enfoque metodológico radica en realizar la mejor proyección del precio de los metales aplicando las mejores prácticas mundiales al respecto. Para ello, se analizan una gran variedad de modelos concluyendo que el mejor modelo a aplicar, debe ser la simulación del precio del metal con reversión a la media con saltos de tipo aleatorio.

Sep 9, 2007

The upper amphibolite-grade mctasediments of thc rinaroo area, North Queensland, form part of a regional aurcole to the large Tinaroo Batholith and are the stratigraphic equivalents of the Hodgkinson Formation of gencrally low metamorphic grade. There is no evidence of any lithological unconformity.The higher grade metasediments have a more complex deformation history than is typical for thc surrounding region and this may bc due to one or a combination of two factors; an additional strain componcnt associated wilh the intrusion of Ihe Tinaroo Batholith, or a more marked finite strain response to the overall regional stress field within hotter. more ductile rocks.Four deformational events can be characterized within Ihc Tinaroo Area. Close to Ihe Tinaroo Batholith D1 and D2, arc so strongly developed that they disrupl the continuily of Ihe original Iithological layering. In the aureole region, D1 is strongly overprinted and its original fabric intensity is obscured, but both D2 and D3 display a mappable decrease in intensity away from the granite margin. These three deformations occurred during Carboniferous or early Permian time. D4 is later and only patchily developed.The broad, moderate pressure metamorphic aureole surrounding the Tinaroo Batholith is a typical of the CairnsCooktown group of Permo-Carboniferous granitoids. which usually develop narrow, lower pressure contact aureoles. Two periods of metamorphism are distinguishable. The first reached peak temperatures somewhat greater than 520°C, the second temperatures around 620-630° C immediately adjacent to the granite contact.Several cale-silicate lenses containing scattered scheelite mineralization occur within the area. Scheelite appears to have crystallized at the same time as the cale-silicate minerals, its appearance coinciding with the intrusion of the Tinaroo Batholith. Unlike many "skarn-type" scheelite deposits, the scheelite-bearing cale-silicates are Fe-poor, with no positive correlation between total Fe and W.

Jan 1, 1982

By P. L. Crouse, S. J. Lubbe, M. J. Kabangu

A selective extraction and separation of zirconium by solvent extraction with 1-octanol is proposed. The process is based on the dissolution of the metal basic carbonates in hydrochloric acid in the presence of potassium fluoride, using 1-octanol as extractant. The effect of several process parameters, including hydrochloric acid and potassium fluoride concentrations, reaction time, and phase ratio between the aqueous and the organic phase was investigated. Zirconium is enriched in the organic phase. The best extraction and separation results were obtained with the basic carbonate dissolved in 10% hydrochloric acid and 1.5 M potassium fluoride. The optimum reaction time was 15 min with an organic to aqueous phase ratio of 2:1. Based on the selectivity of zirconium over hafnium in the organic phase, a McCabe-Thiele diagram was constructed. A near complete stripping of zirconium from the organic phase was achieved using a 3 M sulphuric acid solution. Additional studies are required in order to determine the reaction mechanism and the chemical speciation of the current investigation.

By David Forrester

Subsidence beneath the land surface has traditionally been monitored using the most accurate surveying methods of the day. Over the several hundred years of subsidence investigation, these techniques have improved, and thus the accuracy of subsidence measurements has improved. In circumstances where the subsiding surface is masked by water or rock, novel methods must be developed. This method describes the recent successes of subsidence monitoring using advanced bathymeric techniques in the Sydney Coalfield. In order to obtain subsidence profiles above submarine coal extractions, seafloor bathymetry surveys, run before and after mining, have shown that subsidence profiles can be detected, despite the primitive nature of some of the trials. Very recently, there have been considerable advances in this field, associated with the availablity of high-powered personal computers to control data collection and analyse the results. The recent surveys described in this paper have demonstrated the considerable potential for such methods. This paper describes bathymetric subsidence monitoring developed in the Sydney Coalfield, illustrated with some typical results, and summarizes the findings of the research leading to the development of subsidence design criteria specific to the Sydney Coalfield.

Jan 1, 1996

By Morabito J, Harrop D. W

Uranium exploration was commenced in 1973 and carried out at a regional scale over a wide area of the northern part of the Camarvon Basin of Western Australia by Minatome Australia Pty Limited and their joint-venture partners. As a result, pervasive uranium mineralization has been found in the Cretaceous sandstones near Manyingee Hills in the Onslow Region, which were probably deposited in a near-shore, fluvia deltaic palaeo-environment.Mineralization is generally found in poorly sorted argillaceous sandstones and siltstones near redox fronts formed by oxidizing waters circulating in reduced sediments. The principal minerals found in the two Manyingee deposits delineated so far are coffinite, uraninite with associated pyrite in the reduced zones, and phosphuranylite, siderite and limonite in the oxidized zones. The presence of dissolved uranium in the superficial aquifers, of secondary uranium minerals as coatings on granitic rocks, and of recent uranium-bearing calcrete sediments, suggest that the whole Cretaceous-Precambrian system has been subjected to the formation ofroll-front type uranium deposits since the Cretaceous. Continuing exploration is locating additional uranium occurrences. The deposits outlined so far are being evaluated for their amenability to in situ leaching tests planned for 1982-1983.

Jan 1, 1981

By Keith Merriam, Jim McDonnell, Peter Radziszewski, Rob Rotzinger, Ian DeHart

"Taseko Mines Limited Gibraltar copper-molybdenum mine recommenced operation in 2004 with the initiation of a series of development projects to increase throughput capacity as well as modernize the mine.In the second staged development project, a VTM-1250-WB regrind mill was selected to replace the existing conventional ball regrind mill to achieve a target grind size of 80 % passing 45 µm. In the third staged development project, a second VTM-1250 regrind mill was selected for installation in Concentrator #2, to match the existing Concentrator #1 Vertimill. This resulted in approximately 25% spare regrind capacity in the Concentrator #2 design, complete spare parts interchangeability and potential future expansion capacity to 50,000 t/d with no circuit upgrades.In this context, a study was initiated to assess not only the performance of a Vertimill grinding circuit processing a copper concentrate to a particle size of 80% passing 17 µm but also to provide Taseko’s New Prosperity project specific design information for grinding to particle sizes below 80 % passing 25 µm.The objective of the work described in this presentation was to explore Vertimill ultrafine (sub 100 µm) grinding test methodologies at both the lab and pilot scales, compare the scale-up data with operational data from the VTM1250 at Gibraltar Mines and subsequently apply this information to particle sizes down to 80% passing 17 µm. The presentation will describe the results obtained preceded by a description of the Gibraltar regrind circuit historical operation and operational performance as well as a description of the Vertimill technology.INTRODUCTIONTaseko Mines Limited is a mining company headquartered in Vancouver, British Columbia, Canada. In addition to mining development projects for copper, copper-gold, gold, and niobium properties, Taseko Mines is seventy-five percent owner and the operator of the Gibraltar Mine near Williams Lake , British Columbia. Taseko Mines Limited’s Gibraltar copper-molybdenum mine recommenced operation in 2004 with the initiation of a series of development projects to increase throughput capacity as well as modernize the mine.Metso is a leading process performance provider, with customers in the mining, oil and gas, and aggregates industries. It has corporate headquarters in Helsinki Finland, offices in 50 countries and manufacturing facilities on five continents. Amongst other types of equipment and services, Metso designs and manufactures VERTIMILL® (VTM) Grinding Mills."

Jan 1, 2015

By S. A. H Tyrrell, R. Rotzinger

"Taseko Mines Limited recommenced operation of the Gibraltar copper-molybdenum mine in 2004 and embarked on series of development projects to modernize the mine and increase throughput capacity. The Gibraltar Development Plan 3 (GDP3) project included a second stand-alone copper-molybdenum concentrator, a stand-alone molybdenum separation plant and associated services. Ausenco was contracted to commence the detailed design in 2Q2011, commissioning commenced in 4Q2012 and first ore was processed in 1Q2013. This paper discusses the design, implementation and commissioning of the GDP3 Concentrator.INTRODUCTION The Gibraltar Mine (Gibraltar) property is located in the Cariboo Region of south central British Columbia, approximately 360 kilometers northeast of Vancouver. The site is accessed via an 18 kilometer paved road from the town of McLeese Lake, which is located on the province’s main north-south highway between the cities of Williams Lake and Quesnel. Gibraltar was originally developed by Placer Development and commenced production in 1972. Gibraltar was acquired, while on care and maintenance, by Taseko Mines Limited (Taseko) in 1999 during a period of unusually low metal prices. Taseko recommenced operations at Gibraltar in 2004, and embarked on series of development projects to modernize the mine and increase throughput capacity. The 1972 Gibraltar process flowsheet incorporated two-stage crushing followed by rod and ball milling and flotation. In 2008 Gibraltar completed their first development stage that included the installation of a SAG mill, converting the existing rod mills to ball mills and adding additional flotation capacity. Gibraltar continued development with the installation of an in-pit primary crusher, expansion of the bulk regrind circuit, expansion of the cleaner flotation circuit, replacement of the tailings pumping system and replacement of the concentrate filters and dryer."

Jan 1, 2014

This paper gives an overview of the difficulties associated with determining the strength of hard rock pillars. Although a number of pillar design tools are available, pillar collapses still occur. Recent examples of large scale pillar collapses in South Africa were caused by weak partings which traversed the pillars. Currently two different methods to determine the strength of pillars are used namely, empirical equations derived from the back analyses of failed and stable cases and numerical modelling tools with an appropriate failure criteria. Both techniques have their limitations and additional work is required to obtain a better understanding of pillar strength. Empirical methods are popular and easy to use, but care should be exercise that the results are not extrapolated beyond the range of the data which were used to derive them. An example is the Hedley and Grant formula (derived for the Canadian uranium mines) that has been used for many years in the South African platinum and chrome mines (albeit with some adaptation of the K-value) to design the pillar layouts. Very few collapses have nevertheless been reported and it might even be too conservative an assumption of pillar strength in these mines. As an alternative, some engineers strongly advocate the use of numerical techniques to determine pillar strength. A close examination unfortunately reveals that these techniques also rely on many flawed assumptions. An area where numerical modelling is invaluable, however, is to study specific pillar failure mechanisms, such as the influence of weak partings on pillar strength. In conclusion, it appears that neither empirical techniques nor numerical modelling currently provide a solid basis to conduct pillar design. It is therefore recommended that both these techniques be utilised when confronted with a pillar design to obtain the best possible insight into the problem.

Nov 25, 2010

By Braden T. Lusk, Rex A. Meyr, Kyle A. Perry

Following three major mining accidents in 2006, the MINER Act of 2006 was enacted by MSHA and required every underground coal mine to install refuge alternatives to help prevent future fatalities of trapped miners in the event of a disaster. A polycarbonate safe haven wall for use in underground coal mines was designed and modeled using finite element modeling in ANSYS Explicit Dynamics to withstand the MSHA required 15 psi (103.4 kPa) blast loading spanning 200 milliseconds. The successful design was constructed in both half-scale and small scales in the University of Kentucky Explosives Research Team’s (UKERT) explosives driven shock tube. The constructed polycarbonate walls were tested multiple times to determine the walls resistance to blast pressure. The results for each test were analyzed and averaged to create one pressure versus time waveform which was then imported into the finite element program and modeled to compare deflections of each part to that was measured during testing for model validation. This paper summarizes the results.

Jan 1, 2014

Detailed petrographic analyses of coal seams from the Newcastle, Illawarra, and Lithgow Coal Measures were made for a number of localities for each of twelve seams. From these analyses characteristic standardprofiles were derived for each seam. Two broad types of profile were found; one in which vitrite-poor and vitrite-rich layers alternate, and another in which there is a steady decrease in vitrite from the base to the top of the seam. From comparison of the petrographic profiles it was concluded that the Great Northern Seam in the Northern Coalfield is a possible equivalent to the BulIi in the Southern; and likewise the Fassifern to the Balgowni...

Jan 1, 1967

By Llewellyn A. Rubin

ROUTINES AND SUBROUTINES A- 1 Wait Loop (Wait) A- 2 Receiver Processing (RCVP) A- 3 Control Panel Sequence (CPNL) A-4 Interrupt Routine (INTRP) A- 5 Math Processing Routine (PROC) A-6 Input Constants for Math Routine (CONI) A-7 Angle Conversion Routines (LVERT) A- 8 Display Routine (DSPY) A- 9 Message Print Auxillary Routine (MESSO) A-10 Auxillary Subroutines (AFUTC and AGETC)

Jan 1, 1973

By John Kazakoff, Andrew Mortimore

"Production at the remote Kumtor Gold Mine in Kyrgyzstan commenced on schedule in December 1996.The ore mined during the first few months of 1997 from the upper benches of the pit did not produce the results predicted by the feasibility study. Low metallurgical recoveries experienced at the time were cause for great concern.It soon became clear the recovery difficulties centred around the preg robbing nature of the ore.Procedures were developed to selectively stockpile highly carbonaceous low recovery ore types. Testing methods were developed in the mill to quante the preg robbing activity of the ore. Preg robbing masking agents were added to the process to reduce the preg robbing activity of the ore.The importance of coconut carbon activity relative to the preg robbing activity of the ore was realized. Every aspect of the performance of coconut carbon in circuit was evaluated and optimized to improve carbon activity.Mineralogical analyses were completed defining the deportment of gold in ore and process tailingsBy year end the recovery difficulties had been overcome and plant design production had been achieved. Process improvements continue through 1998."

Jan 1, 1999