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By Bure R

Approximately 2.4 million ounces of gold and 11.3 million ounces of silver have been produced from the Umuna Lode by Misima Mines Pty Limited between June 1989 and the end of Decemeber 1996. Reserves remaining at the end of December were 32.1 million tonnes at 1.0 gram per tonne gold and 9.7 grams per tonne silver. To attain precious metal production of this volume, an estimated K60,000,000 (1996 Kina) was spent on exploration alone. from the 1940s to the present day. Exploration expenditure for the 1996 calendar year was approximately K4,400,000. With such a large investment in exploration, large quantities of data were generated and stored in various forms. To make best use of this data, it was necessary to organise and systematically store this data in a form compatible with a modern Geographical Information System (GIS). The Umuna Lode on Misima Island is a low sulphidation gold- silver deposit dated at 3.5 ¦ 0.2 Ma. The deposit is controlled by the 50 to 100 metre wide Umuna Fault- a moderate dipping, brecciated clay- chlorite- carbonate altered, normal fault zone. There is approximately 230 metres of mostly dip slip offset on this fault, which is measurable by the offset of the Cretaceous schist, marble and greenstone host sequence. Late Miocene microdiorite spatially related to the Umuna Lode does not appear to be genetically related to the gold- silver mineralisation. GIS was introduced to Misima at the end of 1995 and until recently has been mostly used for data storage and retrieval, the over- laying of various data sets to assist in targeting prospective areas, and as a drafting tool. The use of data-driven, predictive data analysis is the most recent effort in maximising the use of the extensive Misima database. By characterising the key controls and properties of the Umuna- type mineralisation, a Weights of Evidence, data-driven analysis produced a prospectivity map of Misima Island. The purpose of this map was to identify prospective areas yet to be explored and to assess the effectiveness of exploration to date.

Jan 1, 1997

By Singh RN

Monolithic packing systems have gained in popularity as a gate side packing method. However, there has been no detailed investigation to assess their underground strength behaviour. This work includes the laboratory and in situ investigation for strength behaviour determined on various monolithic packing materials namely Tekpak-XX, Hydropak-20, Hydropak-30, Astrapak-3R, Flashpak, Thyssen pack and Aquablends. A simple technique for assessing the pack strength was developed at the laboratory by using a penetrometer, of which penetration resistance can be directly correlated with the uniaxial strength of the pack. The in situ strength investigations were made on core samples obtained from three pipes inserted inside the pack, while the penetration test were made on the pack surface. The in situ results indicated that the packing material develops an inconsistent strength on various part of the pack which was mainly related to an inadequate mixing of grouts inside the pack.

Jan 1, 1992

Mr GEPP said: "He proposed at the outset to draw attention to figures dealing with the population of the countries adjacent to Australia for the purpose of comparison with the population of the Commonwealth. He would deal more particularly with the areas of land surrounding the Pacific and Indian Oceans. Korea and Japan had a population of 18,000,000 ; China, 437,000,000 ; Persia, 9,000,000 ; Arabia, 5,000,000; South Africa, 129,000,000; Madagascar, 3,500,000 ; India, 251,000,000; Siam, Indo-China, and so forth, 16,225,000; Federated Malay States, 3,225,000; and, very significantly, Java, only four and three quarter days from Fremantle, over 50,000,000. From the map displayed an idea of the comparative areas of the countries mentioned and Australia could be gained. It was rather amazing that Australia, with its great potentialities, had only about 5,150,000 people. New Guinea had over 750,000 people; Hawaii, a mere speck, 250,000; New Zealand, 1,300,000; North America, 130,000,000; Central America, over 15,500,000; and South America, over 65,000,000. Colombo was only six days from Fremantle, and it was only nine days from Capetown to Albany, and eight days from Albany to Hobart. Proceeding, Mr. Gepp said "It was in 1911 and 1912 that I had the good fortune to spend nearly twelve months in Europe, and during the course of my work in England and Germany to have the oppprtunity of studying both the economical and political systems in some detail... I was in Berlin at the time of the visit of Lord Haldane, when an effort was made by the British Government to arrive at some under...

Jan 1, 1923

By J J. Cilliers

The aim of this paper is to give an overview of the FrothSim flotation simulator and to demonstrate its ability to predict the performance of real flotation circuits. Example simulations are presented in which the feed rate to the circuit is varied, followed by simulations in which a cleaner section and recycle loop are added to the rougher bank.The simulator is able to predict both the recovery and the grade produced by the cells at all locations in a circuit and the simulator is shown to produce plausible grade recovery curves. It also demonstrated that the performance of banks of cells improve as the feed rate to the bank increased (improved grade for a given recovery), but that more cells are required to give the same overall recovery.

Jan 1, 2005

By N J. Welham

The Intec Copper Process is an environmentally advantageous hydrometallurgical process for the production of high purity copper and associated precious metals from copper sulphide concentrates. The process uses a mixed chloride-bromide lixiviant in an elegant cyclic circuit to leach the copper into solution, rejecting the iron as stable hematite rather than as unstable jarosite. After purification of the pregnant liquor, copper is electrowon at London Metal Exchange Grade A purity, while the anodic energy of the cell is stored as the soluble species, HalexTM, for recycle as the regenerated lixiviant to the leach circuit. Both gold and silver are leached and recovered directly from this cyclic process without resorting to cyanide leaching of the residue. No liquid emissions result from the Intec Copper Process, whilst spent air and water vapour from the leach are released to the atmosphere. The sulphur in the minerals reports to the solids residue in elemental form, without the need for expensive handling of voluminous gaseous sulphur dioxide streams found in smelters. A significant difference to competing smelting and hydrometallurgical processes is that any mercury entering the process from the sulphide concentrate feed is recovered rather than reporting directly to waste or polluting the environment. Outside the process circuit itself, the Intec Copper Process has several notable environmental advantages over competing technologies: Flexibility of scale with low capital and operating costs allow operation directly at the mill head at production rates as low as 15 000 tpa, significantly reducing environmental impacts from concentrates transport. The ability to handle low-grade and dirty concentrates often allows greater recoveries in the mill, improving both the economics and environmental acceptability of a mine by reducing metal losses to tailings. A comparison of the total energy requirements of the Intec Copper Process with those of competing technologies shows that the Intec Copper Process has the lowest energy consumption of any of the known hydrometallurgical processes, as well as improving upon pyrometallurgy under appropriate conditions.

Jan 1, 2002

Introduction.History of Stope Filling at Mount Isa.The Need for a Systematic Fill Programme.Reasons for Filling.Fill Materials and Tonnages.Rough Mullock Fill.Quantities Readily Available.Fill Pass Development.Stope Preparation.Drainage.Hydraulic Sand Fill.Initial Experiments with Mill Tailings.Surface Layout.Operation Procedure.Underground Pipe Lines.Life of Sand Pipes and Cones.Drainage.Old Tailings Dam Sands.Quantity of Fill Placed.Pillar Tonnages.Conclusion and Acknowledgment.INTRODUCTIONFilling practice outlined in this paper refers exclusively to the Black Star section of the mine. The stope filling necessary early in the life of the Black Rock and portions of the Rio Grande sections is not to be confused with the current filling programme.

Jan 1, 1953

Increasing use has been made of engineer ing geology and hydrogeology in the development of the infrastructure for mining projects. The Geological Survey of the Department of Mines, the Department of Main Roads, the Irrigation and Water Supply Commission and private consulting organisations and mining companies, employ spec- ialist staff to carry out engineering geological and/or hydrogeological investigations. Such in- vestigations have been of assistance in recent mining developments in northern Queensland, in- cluding those in the Cloncurry - Mount lsa, Weipa, Greenvale and northern Borten Basin areas.

Jan 1, 1974

When lying over 200-250m depth, many seams and surrounding strata are gassy enough to create mining difficulties , particularly in highly productive longwalls as well as in their development headings. In addition to the gassiness of seams or stra- ta in the outgassing volume around working, the shape expansion and limits of this one influences much the intensity of gas emission. These charac- teristics of outgassing volume differ very much ac- cording to the permeabilities of the seams and strata encountered by their fracturation due to mi- ning. Moreover, the shape of the outgassing volume is very much modified by the rate of advance of the face. In nearly impermeable deposits, gas flows from a limited outgassing volume. When the rates of advance of a face are medium or low, the shape and dimensions of this volume do not change very much and outgassing volume is translated progressi- vely with the face advance. This explains why, in the past, it was observed that there was for each seam an average steady specific emission of gas, round which the volume of gas evolved per mined ton or per mined unit area, calculated over a cer- tain time, was oscillating. Combined with a statisti- cal irregularity coefficient, this allowed prediction gas of emission and thus to take decisions for air ventilation, drainage, and eventually production.

Jan 1, 1988

In the stability assessment of open pit walls, geotechnical engineers have to deal with uncertainty related to structural geology, rock mechanical parameters, groundwater and so on. This uncertainty will immediately and significantly impact on wall stability assessment and therefore. influence mineral recovery and ultimately the financial return of open pit mining. However, the conventional factor of safety applied to measure the stability of slopes and the relevant analytical computer packages cannot quantitatively consider the variability or uncertainty of the input data. As a supplement, therefore, geotechnical engineers have begun to apply probability to the stability assessment of open pit walls over the last two decades. To-date unfortunately, no powerful computer package is available to geotechnical engineers to conduct the probability analysis of slope stability. This paper presents a computer package of probability analysis for rock and soil slope stability. In this computer package, the strength parameters of rock and/or soil material such as cohesion, friction angle and unit weight of the different rock and/or soil type domain in a complex structural geology environment can be considered as the basic input random variables. Groundwater level can also be taken into account as a random variable in this package. Two `rigorous' limit equilibrium solutions, the Morgenstern/Price method and the Sarma method, can be used to calculate the factor of safety during Monte Carlo Simulation applied in this program. Five types of probability distribution are included in this package for the user to simulate basic input random variables. Two realistic cases from BHP Iron Ore are used to illustrate this package.

Jan 1, 1997

By S J. Tear, L D. Queen

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Frieda River Project is located in the north-west of Papua New Guinea. The target commodities for a bulk mining operation are copper and gold associated with a large felsic porphyry system. The project comprises a series of deposits, with the Horse-Ivaal-Trukai (HIT) being the largest. It also includes the adjacent smaller Koki and Ekwai deposits.Previous resource estimates for the HIT were made using 14 separate mineralised domains based on structure, copper grades, lithology and alteration. H&S Consultants (H&SC) has revisited the deposit and concluded that a simpler methodology could be used for resource estimation without using wireframes as hard domain boundaries. This conclusion is based on reviewing all the available geological data combined with geological and resource experience of porphyry deposits.It is generally acknowledged that porphyry deposits form by diffusion of mineralising fluids through the host lithologies, meaning that sharp boundaries are unlikely unless these fluids encounter specific physical or chemical boundaries. It is important to prepare a comprehensive geological model prior to attempting resource estimation as it forms the framework for the estimates; however, not all geological features may be relevant to the distribution of mineralisation and there can be a tendency to overcomplicate the estimation process by using too many domains. Unless a hard boundary can be identified consistently and unequivocally, it is generally better not to use a boundary in that location.H&SC completed unconstrained models with no top-cutting using both a simple flat search ellipse and a steep search ellipse to generate global resource estimates reported within a predetermined pit shell at a 0.2 per cent copper cut-off. Both outcomes are within 10 per cent for the tonnes, contained copper tonnes and gold ounces compared to the constrained resource estimate. The slight differences are most likely due to the different search strategies, but also indicate the robustness of the unconstrained modelling approach.CITATION:Queen, L D and Tear, S J, 2015. The Frieda kiss – keeping it simple , in Proceedings PACRIM 2015 Congress, pp 361–368 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By S Maritsa, E K. Chiwandika, S M. Masuka

The iron and steel industry is experiencing an increase in the use of iron and steel commodities within societies, decarbonisation pressures, depletion of high iron ore grades and high energy consumption. This necessitates scrap metal recycling, low-grade ore utilisation using the induction or electric arc furnace to achieve the global target of net zero CO2 emission. The available highquality scrap metal cannot sustain the steel industry but the world has unused hematite-goethite ores. It is the aim of this research that this resource be utilised using the induction furnace to sustain the steel industry in an environmentally friendly manner. Indurated pellets prepared from the hematite-goethite ore, 5 wt per cent limestone and 5 wt per cent coal addition were smelted in the induction furnace at 1350 ± 50°C with 25 mins holding time. The effects of basicity and carbon content were also investigated to optimise the smelting parameters. The results showed that the careful control of the basicity, and iron-to-carbon ratio maximised total metal recovery. The optimal basicity ratio was determined to be 1.3 and a carbon to iron ratio of 1.4 achieved a total metal recovery of 73 per cent. The metal recovery was closely related to the estimated slag melting temperature. The basicity ratio of 1.3 achieved the lowest slag melting temperature estimated to be around 1380°C based on the CaO-SiO2-Al2O3 phase diagram. The recovered metal had a comparable chemical composition and microstructure to that products from an ITmk3 furnace.

Jun 19, 2024

The winning and upgrading of mineral raw materials necessarily includes size reduction, which serves the liberation and production of marketable products from highly valuable and bulk materials. For crushing, the following factors can be duly accounted for depending on material type and the selection of the suitable machine: ò producing a particular size distribution, ò producing a particular grain shape, ò selective comminution, ò gentle comminution, and ò producing a size range required by a specific process and/or for a specific product.

Jan 1, 1993

By J Bower

The JORC Code does not specify a definition for ælevel of confidenceÆ. The common approach in the mining industry is to use a certain drill spacing or number of data samples to classify resources by the confidence categories. Another approach includes application of the quantitative geostatistical criteria for non-subjective and consistent definition of the resource categories. This approach, which has become increasingly popular in the mining industry, provides a quantitative measure of the resource estimation uncertainty. In this study, uncertainties associated with the different drilling grids at the Weipa bauxite deposit (Queensland, Australia) have been modelled using conditional simulation methodology. Criteria used at Weipa for defining resource categories are as follows: mineralisation can be classified as a Measured Resource if tonnage and grade of its volume representing three months of production can be estimated with a precision error not exceeding ¦10 per cent (at 95 per cent probability, ie two standard deviations); and mineralisation can be classified as an Indicated Resource if grade and tonnage of its volume representing annual production can be estimated with a precision error not exceeding ¦10 per cent (at 95 per cent probability). Several different grids have been created by subsampling the drill hole database. The studied variables include Al2O3, SiO2, thickness of the bauxite seam and location of the footwall contact. The variables have been modelled by sequential Gaussian simulation. Based on this study the following drill spacings have been recommended: Measured Resources û 150 m by 150 m, Indicated Resources û 300 m by 300 m.

Jan 1, 2009

By C McCamley

"The requisite for maintaining optimal carbon concentration levels in a carbon-in-leach (CIL) circuit is of paramount importance in the prevention of gold losses. The process’s ability to recover gold from the aqueous phase is primarily dependent on the carbon loading profile of the CIL train.Newmont Boddington Gold (NBG) have over 2015 tested the Mintek online carbon concentration wmeter (C2 Meter) suitability for effective carbon concentration measurements in their CIL circuit compared to the standard method where the readings are taken twice a shift by the operations staff. The C2 meter works by passing a 1MHz ultrasonic signal through a slurry containing carbon where there is a relationship between the carbon concentration and the attenuation of that signal.It also highlighted another area where the C2 meter could be implemented at NBG whereby the instrument can be as a cautionary device for carbon losses in place of carbon safety screens.Citation:McCamley, C, 2016. Continuous Carbon Concentration Measurement at Newmont Boddington Gold, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 207–212 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By W Curlewis, D Hake, Z Cuthbert

The South Island Line (East) will be a medium-capacity railway covering approximately 7 km from Admiralty Station to South Horizons Station on the south side of Aberdeen Harbour in Hong Kong, with intermediate stations at Ocean Park, Wong Chuk Hang and Lei Tung.South Island Line (East) Contract 904 project is located on the island of Ap Lei Chau at the southern side of Hong Kong island and requires extensive construction works to be completed in close proximity to the existing residential estates of South Horizons and Lei Tung. The project also has areas of significant cultural heritage, including 18th and 19th century temples and historical gravesites. Owing to the site access constraints and location for the project, detailed planning and methodology innovations have been required to ensure the most effective and responsible means of delivering the project works. To excavate the tunnels using drill-and-blast techniques in these restricted locations, the maximum instantaneous charge weight that could be fired while blasting was severely limited. To overcome these restrictions, the project team developed and pioneered the use of ‘deck loading’ in Hong Kong to minimise the impact of blasting operations and has successfully implemented double- and triple-deck blasting operations during the completion of tunnel excavation works.Upon completion of the drill-and-blast excavation, the tunnel lining works were completed using both in situ concrete lining with travelling forms and permanent shotcrete works.CITATION:Curlewis, W, Cuthbert, Z and Hake, D, 2014. SIL904 Hong Kong – Drill and Blast Tunnels, station blasting innovations (double- and triple-deck blasting) and lining solutions, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 21–28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By A Singh, C Da Corte

Banded Iron Formations or more commonly known as BIF are sedimentary rock formations with alternating silica-rich layers and iron-rich layers that are typically composed of iron oxides (hematite and magnetite), iron-rich carbonates, and/or iron-rich silicates. Considering the depletion of highgrade iron ore reserves in South Africa, there is a need to maximise resource utilisation through the exploitation of sterile resources in particular BIF material which makes up greater than 65 per cent of current reserves. BIF, like most resources, is non-renewable and the deposition of BIF is thought to have come about by the reaction of Fe2+ ions in the ocean water with dissolved oxygen billions of years ago. BIF ore derived from the Limpopo region in South Africa (SA) located in the Penge Iron Formation is according to Cairncross, Kramers and Villa (2018) equivalent to that contained within the Asbestos Hills Iron Formation of the Transvaal Supergroup in the Northern Cape, SA. Considering that these are one of the largest iron ore deposits in SA, the case study involved mineralogical characterisation followed by beneficiation of BIF from these two regions to ascertain the comparability. Coarse and fines gravity separation comprising of Heavy Liquid Separation/Dense Media Separation on the +1.18 mm size fraction and shaking table on the -1.18 mm size fraction was conducted to ascertain whether an on-grade product or blended feedstock could be produced. The Limpopo mixed and Northern Cape conglomerate BIF samples achieved similar overall responses due to the conglomerate sample containing 15.3 per cent additional -1.18 mm fines. A combined coarse and fines product grading at 60 per cent Fe could be achieved at a yield and recovery of 43.9– 53.0 per cent and 62.2–63.8 per cent respectively. Increasing the grade to 63 per cent Fe reduces the overall recovery by 13.3 per cent. At the higher target grade, the contaminant specifications could be achieved for both samples. The Northern Cape laminated BIF sample is the most promising of the three samples studied. At the two iron target grades overall yields and iron recoveries of 72.9–65.4 per cent and 85.2– 80.2 per cent was achieved. In both instances the silica grade exceeded the product specification, however if the silica content is the driver the target iron grade should increase to 63.32 per cent. This will result in a minimal decrease in recovery of 0.4 per cent. The promising results of this study indicate that coarse beneficiation of BIF material is possible. These ore types could be blended with superior grade products to improve overall yields and recoveries or sold directly at a 63 per cent Fe product grade whilst sacrificing 0.4–13.3 per cent recovery.

Nov 8, 2021

By T Purvis, J Calverd, A-K Greve

The Ernest Henry Mining (EHM) underground mine is situated adjacent to the Great Artesian Basin in North Queensland and within a fracture zone. Underground development commenced in February 2008 and has extended to approximately 1000 vertical metres below the surface.Groundwater has been encountered in numerous locations throughout the mine, predominantly on the eastern side of the orebody and often related to fault structures. Most of the groundwater encountered has been managed with conventional pumping systems; however, on occasions large water inflows have been encountered, which have had a significant impact on the planned development of the mine. Some of the intersections encountered had the potential to compromise the mine from a combination of high temperature (over 45°C), high pressure (3500 kPa) and high flows (50–100 L/s).This paper describes three case studies where significant water inflows were encountered and then controlled by the injection of cementitious grout into the rock mass. The case studies are the 1650 mid-shaft heading, the 1325 shaft access decline and the 1625 to 1475 fresh air rise (FAR) raise bore. Each case study includes a brief description of the event that occurred and the grouting equipment and techniques developed to enable mining to continue.The paper also describes the development of a hydrogeological map of the mine, the probe-hole regime used for high-risk headings and the required processes and systems to inject both cementitious grouts and polyurethane resin into the rock mass.CITATION:Purvis, T, Calverd, J and Greve, A-K, 2014. Management of high-pressure groundwater in underground development at Ernest Henry Mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 217–226 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By W Kendall

Ore sorting has the potential to reduce the feed to wet plants and in the case of complex orebodies that can significantly reduce the water, energy and reagent consumptions and resulting operating costs for the project. The application of ore sorters has sparked renewed interest and application in the precious and base metals mining industry in recent years as a result of the continuing development of new sensing technology and very fast information processing that is making ore sorters applicable to a much wider range of ores and larger scale operations. The application of ore sorters involves a range of trade-off decisions that have economic impact upon the benefits of ores sorting to the project under consideration. This paper will present some typical trade offs to be considered and their impact in a particular project setting. CITATION: Kendall, W, 2018. How economics drive the application of ore sorting, in Proceedings Complex Orebodies Conference 2018, pp 24–27 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By Bedford D. J

The post pillar cut and fill stoping method has been adopted by King Island Scheelite for the extraction of the main Dolphin orebody. The orebody is a massive, tabular deposit varying from 10 to 50 metres in thickness, and dipping at approximately 30¦ towards and under the sea bed. The mining method was selected for 1. maintenance of hangingwall support under the sea bed; 2. maximisation of first stage ore extraction; 3. flexibility of mining, allowing maintenance of grade and selective mining around waste bands within the orebody, and 4. compatibility of existing equipment both with stoping and the on-going underground mine development programme. Stope parameters were established on the basis of initial rock stress analyses, and since the undercut phase of mining the stoping programme has been monitored with various types of deformation measuring devices installed in a series of large diameter boreholes.

Jan 1, 1977

By F Hungerford

"In-seam drilling has been undertaken for the past 30 years for gas drainage to reduce the risk ofoutburst and lower the concentrations of seam gas in the underground ventilation. The drillingpractices have reflected the standards of the times and have evolved with the development oftechnology and equipment and the needs to provide a safe environment underground. Earlypractice was to adapt equipment from other fields, but with changing emphasis, research anddevelopment by the coal industry has created specifi c equipment, technology and practices toaccurately place in-seam boreholes to provide efficient and effective gas drainage."

Jun 1, 2012