Search Documents

By R M. Yanamandra, M Kumar, S K. Tripathy, N Mangadoddy, P Sudikondala

Spiral concentrators are one of the flowing film gravity concentration devices used to beneficiate coal and mineral ores. The aim of the current study is to understand the particulate flow and separation performance of an LD9 spiral concentrator using a multi-phase Computational Fluid Dynamics (CFD) model. The CFD model utilises the Algebraic slip mixture model to simulate particulate flows. The model employs the Renormalisation group (RNG) k-ɛ turbulence models to resolve the fluid turbulence. Initially, the volume of fluid method was adopted to track the water-air interface. Simulations were then carried out at low (0.3 and 3 wt.%) and moderate (15 wt.%) solids concentrations. Multiple particle-phase representing particles of poly sizes (75–1400 µm) and multi-densities (1450–2650 kg/m3 ) were simulated to study the particle segregation on the spiral trough surface. The numerical predictions are compared with the literature performance data at a diluted pulp flow rate of 6 m3 /hr. The results were found in close agreement. Further, the same CFD model is used to study the change in pulp velocity, streamflow rates, and separation performance at increasing solids concentration. For the same density particles, Fine particles mostly show higher volume concentration in the middle and outer trough regions, whereas coarse particles show higher volume concentration in the interior and central trough regions. It implies that the fine particles mostly segregate towards the outer region, and dense particles segregate towards the axial column.

Aug 24, 2022

THE nature of the ore deposit of the Broken Hill line of lode is such that it can be broadly divided into two the calcitic and siliceous ore bodies. The principal minerals occurring in these ores are: Galena, sphalerite, pyrite, arsenopyrite, chalcopyrite, pyrrhotite, calcite, rhodonite, garnets, feldspar, fluospar, quartz.Whilst these minerals persist in both classes of ore, the following typical analyses of Broken Hill South Limited ore bodies will give some indication of the disposition with regard to each:

Jan 1, 1928

The traditional form of project financing for resource related projects has involved project financings structured with either recourse to the project sponsor(s) or commercial banks accepting the project's risks, usually after project completion, subject to, inter alia, the nature of the project, geographical location, quality of the projected cash flows and commodity price outlook. However, the concept of commodity-linked borrowings hasadded a new dimension for borrowing opportunities for resource-oriented projects and or companies.

Jan 1, 1985

By P Blattner

The Late Miocene gold-silver bearing epithermal system at Waihi has some close similarities in its paleo-thermal and geochemical structure with modern, volcanic-hosted geothermal systems such as Ohaaki-Broadlands. At Waihi an extensive braided quartz vein system is enveloped by hydrothermally altered andesites with minor tuff breccias and tuffs. A main stage of vein filling consists of multiple phases of chalcedonic quartz and fine to medium grained quartz, which are accompanied by pyrite, sphalerite, galena, chalcopyrite and acanthite below the base of oxidation. Platy calcite is present locally. Fluid inclusion studies indicate that the main stage quartz was deposited at temperatures of 189¦-273¦C from dilute (Tm of -0.1 to -1.0¦C) fluids that were locally boiling. Homogenisation temperature Th versus Tm data points lie within the field enveloped by dilution and boiling/gas loss paths determined for the Ohaaki geothermal field, and indicates that the parent hydrothermal fluid for the Waihi epithermal system had a similar composition to that at Ohaaki, ie 0.2 wt% equiv NaCl and 3.3 wt% equiv CO2. The hydrothermal alteration mineralogy and the isotopic composition of vein calcite indicate that the hydrothermal fluid contained relatively high concentrations of CO2 , as at Ohaaki. Oxygen isotope analyses of main stage quartz range from 6.1 to 11.6 %0 and of vein calcite from 2.29 to 9.4%0. Calculated d18Owater values for the hydrothermal fluid that deposited the main stage quartz range from 2.0 to -5.7%0, with a trend to less negative values with depth. They are similar to those in the deep chloride fluid in active geothermal systems with a substantial fluid throughput. A high fluid throughput at Waihi system is also evident from the extensive high intensity hydrothermal alteration and large volume of quartz deposited in the vein system.

Jan 1, 1995

By Whiten WJ

A method that allows data to be mass balanced and screen models to be fitted in a single step is described. The inclusion of several variables to describe the feed data in the fitting procedure allows a mass balance to be conducted at the same time as the fitting of the screen model. Analysis of Groote Eylandt Mining Company screening data has demonstrated that this method is ideally suited to applications where complete stream data are not available. Also, certain random fluctuations in screen model parameters arising from the fitting of consecutive mass balances and screening models are significantly reduced. A cubic spline function with fixed knot positions corresponding to particle sizes and variable (fitted) cumulative percent passing values is used to describe the feed size distribution. When the spline function is interpolated at the experimental feed particle sizes a fitted feed size distribution is obtained. This feed size distribution is then used as input to the screen model calculations from which product size distributions are generated. Since both feed and product size distribution data are used to minimise the residual errors between the observed and fitted stream size distributions, a mass balance is Conducted simultaneously with the screen model parameter fitting.

Jan 1, 1984

By J P. van Dyk

A new crude ilmenite beneficiation process was recently proposed that allowed for the preparation of a smelter grade ilmenite from ilmenite with elevated chromium content. Magnetising roasting was not utilised in the process. As part of this circuit an ilmenite low susceptible reject stream was produced that had a low magnetic susceptibility. In this article a magnetising roasting process was investigated to beneficiate this material. Tests were conducted on material produced by pilot scale simulations on a typical South African East Coast heavy mineral reserve. The results obtained were compared to those published in literature for crude ilmenite. The small-scale experiments were used to define approximate operational limits for the oxidising roasting of a low susceptible ilmenite low susceptible reject stream, although industrial roasting conditions may differ significantly from those obtained in laboratory units. In a next phase these results will be confirmed on pilot plant scale.

Jan 1, 2001

Using a Jarrell-Ash "Compact" direct reading spectrometer, analyses were made of a wide variety of rocks ranging from acidic to ultrabasic types. Statistical evaluation suggests that accuracies comparable with the values obtained by the rapid chemical methods used by the United States Geological Survey will be obtained.The spectrographic method involves fusion of the rock with lithium tetraborate, strontium being incorporated in the flux as the internal standard. The resulting bead is ground with graphite and pressed into a pellet. The counts obtained on two standard pellets are used to correct for instrumental drift.Background readings are made at 4109 Å and corrections for background are made to all lines. Corrections for matrix interferences, both by chemical suppression and optical enhancement, are made. The three corrections of drift, background, and matrix are incorporated into one general expression which has been programmed on magnetic cards, each element requiring a separate card. The cards are placed individually into a desk top computer (an Olivetti Programma 101), which enables true counts to be calculated from the "readout" counts, and the element concentration is then obtained from computer-printed tables by referring to the appropriate value of true counts versus concentration. These tables were prepared by making a polynomial regression analysis of the spectrographic results from 50 standard and analysed samples, a curve of best fit being chosen for each element.The regression coefficients, usually of a fourth or fifth degree equation, together with other relevant data, were fed into a large computer, programmed to print out tables of concentration versus true counts. This technique enables the results obtained to be based on mathematically-derived values rather than on hand-drawn calibration graphs, giving greater inherent accuracy. The technique has been shown to give results of good accuracy and acceptable precision suitable for many geological and geochemical exploration programmes involving the analysis of many rock samples of different types.

Jan 1, 1969

By G Hancock, J Lowry, T Coulthard, W Erskine, M Saynor

An important part of planning for the rehabilitation of uranium mine sites is the ability to assess the geomorphic stability of the final landform, over time frames ranging from decades to millenia. Depending on the environmental conditions, erosion features such as gullies may incise into containment structures, potentially leading to the exposure and transport of encapsulated radioactive material. Further, erosion may lead to increased sediment loads and the transport of other mine-related contaminants off-site and into downstream waterways. While erosion may be monitored and assessed over the short term (years to decades), the longer-term behaviour (centuries to millennia) of such landscapes is not within any meaningful human management time frame. Landscape evolution models (LEMs) can provide information on soil erosion rates at decadal or centennial scales over large spatial scales, and evaluate the sensitivity of these processes to environmental changes. However, an important issue associated with the use of models is the ability to assess the reliability and accuracy of the model. In this paper, the CAESAR-Lisflood LEM is tested for its ability to predict soil erosion from a series of 30 m × 30 m experimental plots specifically constructed for this purpose on a trial rehabilitated landform at the Ranger Uranium Mine in the Northern Territory, Australia. Model predictions of bedload and suspended sediment loads from the erosion plots were compared with field measured observations collected over four wet seasons from the trial landform. Once calibrated for the specific site hydrological conditions, the predicted sediment yield – specifically, bedload – demonstrated an excellent correspondence with the field data. However, longer-term simulations of ten years identified an exhaustion effect in sediment yield from the landform. These latter results indicate that a weathering function needs to be incorporated into CAESAR-Lisflood to ensure confidence that the CAESAR-Lisflood LEM will be able to correctly predict the long-term evolution of a rehabilitated landform once it has been?constructed.CITATION:Lowry, J,?Saynor, M,?Erskine, W, Coulthard, T and Hancock, G, 2014. A multi-year assessment of landform evolution model predictions for a trial rehabilitated landform, in Proceedings Life-of-Mine 2014 , pp 67–80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Baxter J. L

Post-tertiary training programmes have been designed and produced for geologists at different levels of understanding and expertise in the relationship between gold mineralization and shear zones. A workshop format was used as it allowed both clients and facilitators to participate in the learning process. Evaluation by facilitators and participants refined the workshop programme as an effective skills oriented learning process. The general observation is that post-tertiary training in small, interactive, practical, learning oriented groups is far better than lecture oriented short courses for developing skills based learning. The evaluation indicates that the process in post-tertiary training must include aspects which are both useful and used.

Jan 1, 1989

The far reaching consequences of designing pillars for coal mines, while retaining concern for safety and economics, are cause for the search for refinement of the existing engineering methods to continue. Coal pillars, while having various functions within the overall mine plan, are the basic structural elements that assure the stability of a mine. Reliable coal pillar design methods take into account criteria which the pillars should meet in specific applications. These applications include typical mining situations such as the partial extraction room and pillar method with and without subsidence considerations, high extraction rate room and pillar, longwall mining chain pillars, and barrier pillars. However coal pillars are onlyu one element of a three element roof-pillar-floor system, weakest element of which system usually determines the stability of the excavations; however, the mining engineer can ony change dimensions of a pillar, properties of the surrounding strata remain beyond his control. The state of the art approach in pillar design places emphasis on recent developments in research. A widely encountered problem in certain coal fields is where pillars are underlain by weak floor strata. The resultant pillar design constantly maintains the perspective of the reliability of the design.

Jan 1, 1991

B. P. Thomson (South Aust. Dept. of Mines): Dr. A. B. Edwards presents in the published discussion on the above paper, his interpretation of the dolerite dyke-lode relationship as a major objection to the syngenetic origin for Broken Hill ore bodies to which Mr. Condon subscribes.Dr. Edwards claims that the dyke-lode relationships indicate clearly that the Broken Hill orebody was formed after the folding and regional metamorphism of the Willyama Series. Field evidence compels m:e to join with H. F. King (1958), in finding this conclusion unacceptable-as follows:(1) Broken Hill type mineralization, as defined by King and Thomson (1953), is clearly confined by the regional sillimanite isograd and does not extend into the lower temperature almandine and biotite zones as does the Thackaringa type mineralization.(2) In the Corruga area the writer has mapped a dolerite dyke apparently cutting a conformable quartz gahnite lode of the Broken Hill type (see Edwards 1958, p. 12).(3) At the Champion mine a similar lode is cut by a fine grained granite dyke.An alternative history of the dolerite dykes to that given by Stillwell & Edwards (1956, p. 26) appears possible. It has been suggested by the writer in an unpublished thesis, (Thomson 1955, p. 30), that the pyroxenite and serpentine plugs and dolerite dykes are rheomorphic end-products of a complex regional metamorphic and metasomatic process involving the formation of amphibolite and pegmatite. The analogy in composition between the dolerite and normal amphibolite is close (see Edwards 1958, Fig. 1, p. 22).

Jan 1, 1959

A fundamental component of grade control at Tarmoola Mine has been the monitoring of assaying through quality assurance programs. The programs have concentrated on issues related to accuracy and precision of leachwell and fire assay techniques, sample preparation and grade variability within a sample. An outcome of monitoring has been identification of shortcomings in the application of assaying techniques to Tarmoola ore types that contain coarse particulate gold. Leachwell has shown satisfactory precision since introduction as the primary assay technique in October 1998 but leachwell accuracy and recovery through comparison with fire assay techniques has identified bias. A bias toward higher fire assays in grades above 2 g/t invoked an investigation into the cause of the discrepancy between leachwell and fire assay. Testwork evaluated Leachwell assay recovery by varying leach time duration, which showed that by increasing the leach time improved recovery significantly. Monitoring of leachwell against fire assay had shown that a leachwell (200 g) with a one hour leach has under-called grade when compared with fire assay by up to 18 per cent, on average, for Tarmoola ore types. Alternatively, optimisation of the leachwell assaying technique using a 200 g pulp and a two hour leach has returned, on average, higher assays than fire assay by up to eight per cent. Testwork on screen fire assays, duplicate assays and fire assay to extinction has demonstrated assay variability associated with coarse, particulate gold. The variability and distribution of gold in Tarmoola ore types has emphasised the importance of high quality sample preparation for leachwell assaying to ensure liberation of gold to leaching solutions. Assay quality assurance protocols are vital to assay data integrity and enable confidence in delineation of ore-waste boundaries and provide early recognition of problematic assaying periods and isolation of grade control practices, which depart from performance standards critical to the operation.

Jan 1, 2000

By Cawte D. C, Just G. D, Whitchurch K. D

The stringent marketing specifications included in coal contracts mean that coal producers must supply cleaner and more consistent coal than may have been formerly required. Geostatistics has the potential to aid in the accurate estimation of the washability characteristics of coal. A prediction method, the Kriged Service Variable Approach has been developed.A Computer Aided Drafting and Design system has proved useful in the development and application of the approach. The geostatistical approach has been tested against coal geological and borehole data and applications discussed.

Jan 1, 1987

The Australian Mining Industry Council (A.M.I.C.) was established in 1967 as a body to co-ordinate the interests of the mining industry on a nation-wide basis. Its member- ship now embraces the great majority of mining groups in Australia. One of A.M.I.C.'s major continuing functions since its formation has been to work with Governments towards the enactment of more effective and efficient mining legislation. Yet, over the period, the,overall position, if anything has deteriorated. The main reason for this was that because of the rapid succession of what appeared to be quite separate problems during the period there was never sufficient time for Govern- ments to take stock of a situation before it would be changed by a new set of circumstances. By early 1973, the Council was certain that most of the various questions raised were really part of the one overall land use problem and its work in this area thus took a new emphasis from that time. In discussing the Council's involvement with Australian mining legislation over the last six years, the paper helps to clarify the present situation. It then explains a land management system which the Council believes could pro- vide the basis for the type of enlighened

Jan 1, 1974

By Haukka M. T

A new low-dilution fusion method which has been successfully used for accurate determination of the major oxide components of silicate rocks, is applicable to rapid, accurate determination of trace or minor eiements in mineral exploration samples. Limit of detection is in many cases less than 5 ppm. Either rapid, approximate measurement and calculation methods (suitable for geochemical exploration), or more accurate methods (applicable to orebody evaluation studies) may be used.Rapid methods are described for nickel in rocks and sulphides containing 10 ppm to >2 per cent Ni, and for gallium. The rarely-determined element gallium is an example of a constituent which may be easily investigatedby XRF using the LiB02 fusion disc, which is a permanent, easily-stored analytical sample available for later rapid or accurate analyses. The method is applicable to over 30 elements at levels encountered in mineral exploration.

Jan 1, 1978

By Griffin PT, Espinosa-Gomez R, Jameson GJ

Two major issues are to be addressed in the Copper Concentrator of Mount Isa Mines Limited. The first of these is the need to increase concentrator flotation capacity to increase copper recovery, while the second is the need to reduce the iron sulphide dilution to meet future smelting requirements. Extra capacity in the cleaner and retreatment sections of the concentrator have been identified as key target areas, with additional copper recovery of at least one per cent identified from plant trials. Extensive pilot plant tests have been undertaken to evaluate the performance of the Jameson cell compared to conventional mechanical cell and column circuits. This work has shown that Jameson cells present an opportunity to achieve the desired grade and capacity specifications at lower capital cost than available alternatives. This paper outlines metallurgical results of work undertaken in the Copper Concentrator, together with a summary of pertinent Jameson cell operating parameters investigated during the period.

Jan 1, 1993

By Fabjanczyk M. W

A limitation to present theoretical roof reinforcement design methods is the inability to derive accurate and quantitative information about the roof rock condition and the action of reinforcement at various excavation stages. To obtain the information required to assess roof rock stability, detailed monitoring of the in-situ behaviour of reinforcement and roof strata is required. Reliable instru- mentation and techniques have been developed for use in underground coal mines to identify the geometry and magnitude of displacements occurring in roof rock and the forces generated in reinforcement. The use of such instrumentation allows an accurate assessment of the in-situ capability of reinforcement and the mode of reinforcing action developed. In-situ monitoring can supply data required for the practical design of reinforce- ment and assess the potential stability of current designs. The use of such data together with mine wide appraisal of rock and stressfield considerations, can allow roof reinforcement to be designed on the basis of a predicted roof Response.

Jan 1, 1986

By D Craw

Uplift of the antiformal ranges in Central Otago, New Zealand , has resulted in the progressive evolution of eluvial placer deposits in tectonic sediments on the range flanks and along their margins. The placers are derived from the reworking of fine-grained gold from the auriferous Manuherikia Group fluvial sediments which covered the basement prior to uplift of the ranges. Gold in the tectonic sediments at Matakanui shows a progressive increase in grainsize in successively younger sediments and nuggets in the youngest gravel sequence are up to two orders of magnitude larger than gold grains in the parent alluvial source. Most of the gold in the tectonic sediments is highly irregular in shape, commonly with delicate surface textures which could not have survived fluvial transport and are indicative of authigenic precipitation. Some coarse grains have been rounded by recycling, and further addition of authigenic gold has occurred. Placer gold values result from both physical and chemical enrichment during sedimentary recycling. Continued range uplift and back-thrusting of sediments on to the ranges results in recycling of earlier formed placer sediments. They also result in further enrichment of gold values through the incorporation of additional supplies of the parent alluvial source sediment The host sediments are widespread along the ranges and are not confined to sites of historic mining activity.

Jan 1, 1992

By V Mutton, L Potts, D Joyce

This paper describes the method of extracting sill pillars within the underground operation from under unconsolidated mullock fill at the Cracow Gold Mine. This pillar recovery method was initially successfully used to recover sill pillars at Crusader Mine, Western Australia in 2001. Globally significant resources have been sterilised due to the placement of loose rock fill above crown pillars and within adjacent stopes. The method described here offers significant opportunities to increase recovery of sill pillar recoveries.The royal orebody sill pillars at Cracow Gold Mine form a significant resource. Extraction of these pillars needed to be undertaken with minimal ore dilution and maximum ore recovery. The application that was selected to consolidate the loose mullock fill above each pillar used an injection grouting process (Minova FB200).Cracow Gold Mine mining method is bottom up bench mining. The pillars were left within the orebody to allow for stoping to commence whilst the decline was being developed. Due to the remainder of the orebody being extracted the only access to consolidate the backfill was from the sill pillar extraction level. Numerous problems were encountered and overcome from product selection and trial, system of injection to extraction.This pillar recovery process achieved a 95 per cent recovery of the sill pillar compared with an estimated 60 per cent typical for other mining options.CITATION:Potts, L, Mutton, V and Joyce, D, 2012. Pillar recovery at Cracow gold mine using grouted consolidated mullock, in Proceedings Narrow Vein Mining 2012 , pp 179-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By J Simpson, M Johnston

Recently Mount Isa Mines undertook a study to review the lead-zinc orebodies to extent of resource and reserves and determine the new life-of-mine schedule, as the Mount Isa and Hilton orebodies had not be reviewed for many years. Also, the recovered value of the Mount Isa, Hilton and George Fisher orebodies had been increased by major performance improvements in the lead-zinc concentrator. The Mount Isa Lead-Zinc concentrator processes fine-grained lead-zinc ore from the Mount Isa, Hilton and George Fisher orebodies. These orebodies have varying levels of pyrite and large variation in the grain size and texture of the galena, sphalerite and pyrite. This variation has a large effect on the recovery of the lead and zinc in the concentrator. Some ores achieve 90 per cent recovery at target grades, yet other ores are unable to achieve æsaleableÆ concentrate grade, with no metal being recovered to concentrate and therefore effectively losing the contained metal to the final tailings. Models were created to predict the metallurgical performance of these orebodies, to better reflect the variation that occurs. These improved metallurgical models and economic data allowed the determination of the Net Smelter Return (NSR) for each block in the geological block model. This NSR is the return to MIM of the metals contained in concentrate. The NSR was used as the cut-off grade criteria when determining the value of the ore. This formed the basis of the lead-zinc life-of-mine schedule and the optimisation of the lead-zinc business.

Jan 1, 2003