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By Hoffmann CF

Thermal conditions at depths of several k.i'-.r.,etres in hydrothermal systems are a major (actor controlling gold transport into the epithermal environment. Understanding of the coupling of thermal, metal and ligand (HZZ S) sources in the root zones of hydrothermal systems therefore becomes important for the application of tectonic and igneous petrochem- ical studies to regional scale precious metal exploration. The evaluation of favourable conditions in this source zone and application to explor- ation rests on a detailed knowledge of the gases, H2S, CO2 hydrocarbons and other trace components preserved in fluid inclusions. Recent developments in analytical techniques now permit examination of these components and the recognition of complex hydrocarbons in rluid inclusions from epithermal and other lydrothermal systems appears promising for ieoosit-source correlation.

Jan 1, 1987

By Booth S. A, Milton D. W

Stratabound/stratiform and remobilised mineralisation have been recognised as the two dominant styles of mineralisation which constitute the Broken Hill ore deposit. Recognition of prospective sites for accumulation of ore depends on understanding the heterogeneity of the ore environment and the distribution of the two styles of mineralisation. The internal stratigraphy of the Broken Hill ore deposit and its enveloping rocks, is described, and a generalised stratigraphic setting of the stratiform mineralisation is outlined. Fhiphasis is placed on the existence of closely-spaced sub-basins as potential sites for ore accumulation close to the Broken Hill ore deposit. Further from the immediate ore environment, recognition of the same diagnostic stratigraphic sequence

Jan 1, 1983

By Whiteman P. C, Stacey G. S, Hunter G. D

Processing of lead-zinc and copper ores by Mount Isa Mines Limited produces large quantit- ies of concentrator tailings waste which is pumped as a slurry to special dams where the solids are allowed to settle and dry out. These areas are unattractive and show no signs of encroachment by plant life even though the surfaces of some dams have remained undisturbed for more than a decade. During 1970 Mount Isa Mines Limited commenced a long term research program in conjunction with the Department of Agriculture, University of Queensland to deter- mine possible methods of establishing a plant cover on this material. Research has defined the major factors limiting plant growth in the tailings medium. Modification of the edaphic conditions through fertilizer inputs, particularly of phosphorus and nitrogen, and alteration of "soil" physical properties by incorporation of mulching mater- ials, provided conditions which allowed plant growth. The outstanding "soil" amendment treatment was incorporation of fly ash, a waste product of the company's coal fired power stations. A range of crop and pasture species have been selected which have grown well with adequate irrigation under the amended conditions in the field. Further research is assessing a range of native plant species and agronomic techniques to provide a stable plant cover on the tailings dams.

Jan 1, 1974

By K Fiedler, A Newell, P D. Munro

Test work is the foundation upon which the success of projects and subsequent operations is laid, reflected in Professor Arthur Taggart’s pithy observation: ‘Make your mistakes on the small scale and your profits on the larger scale’. Indeed, Professor AllanTrench has succinctly noted that ‘Get the metallurgical characteristics wrong and you don’t have a project’.With deposits becoming lower grade, more structurally and mineralogically complex, final products requiring lower levels of impurities and tailings management demanding more attention, test work now assumes even greater significance in the acceptance and successful execution of a project. This paper is the first in a series aiming to stimulate thought on the metallurgical test work process by getting back to the fundamental basics through exploring and providing some guidelines for the metallurgical testing world, noting preferred practices as well as precautions and mitigations. This covers the key characteristics of metallurgical test work programs, including what needs to be done, sample selection, quality control and associated drivers, and most importantly, selecting, assessing and managing test work facilities. CITATION:Newell, A, Munro, P D and Fiedler, K, 2018. Metallurgical test work – between a rock and a hard place, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 15–32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By F Radke, P A. Tilyard

Determination of the mineralogical location (deportment) of minor and trace elements (including credit and penalty elements) in base metal concentrates can indicate whether further processing is likely to (a) reduce the levels of the penalty elements, and/or (b) direct selected elements into other plant products, thereby increasing current concentrate grade or increasing payment for credit elements. To determine the deportment of elements requires knowledge of the proportions of the minerals present and their individual element contents. In addition, knowledge of the liberation and locking is important, as this can affect any possible further processing. Mineral proportions can be determined by a variety of methods including chemical analysis, point-counting, area-counting, QEM*SEM, image analysis and mineral separation. In the case of a Broken Hill zinc concentrate, several of these methods were used and gave consistent results.

Jan 1, 1998

By E J. Cowan

Efficiency demands that mine geologists devote the most time to tasks where they can have the biggest effect on production. One of the most time-consuming tasks is geological interpretation of the orebody and turning this into a block model for the planning engineers.The current best practice for mines that require a geologically constrained resource model involves capturing the interpretation of geologists as three-dimensional (3D) wireframes. However, there is significant overhead in the production of valid wireframes from sectional and plan interpretations. This overhead consists of the mundane tasks of digitising polylines, then building 3D wireframes and validating them. While software can simplify this task, the current process is not the best use of a geologist’s time. Under time pressure exerted by planning engineers and the time required for modelling from polylines, geologists are forced to roll-up the presence of other elements or impurities into the interpretation and encode them in the polylines, even though it is often desirable to consider these other factors separately.While it might seem unlikely that mine geologists can produce constrained geological models without the intermediary of wireframes, the technology to accomplish this is getting closer.In this paper, the results of a trial at the Savage River magnetite mine, which is owned and operated by Grange Resources Ltd, are reported. The trial was for a ‘direct-to-block’ implicit geological modelling method. The focus was on creating a geological attributed block model from drill hole geological log data; resource estimates were not determined. The categories modelled were air, waste, low-grade ore, medium-grade ore, and high-grade ore. The block model outputs either resulted in a proportional block model (categories expressed as percentages within equivolumetric blocks) or a sub-blocked model (parent block and one sub-block), which is the preferred block model output at the Savage River mine. When compared to the traditional best practice modelling method, which takes 43 work days, the wireframe-free modelling method took only 26 hours from initial modelling, using both exploration and grade control data. An update using appended drill hole data is achievable within one day. These results represent time savings of more than one order of magnitude compared to the traditional workflow, and, as such, these figures merit serious consideration for the use of the direct-to-block modelling approach at other operations.With these time savings, geological and estimation models can be kept updated constantly; geologists will not need to set aside two months for quarterly or half-yearly modelling of the drill hole data for resource review. Such dramatic time savings will allow for the better use of highly skilled geologists, who are in short supply in the current market, and will also impact directly on downstream mining engineering workflows.

Aug 22, 2011

By J Zhou

Gold in sulfide ores is associated predominantly with sulfide minerals and occurs as both microscopic and submicroscopic particles. In non-refractory sulfide ores, gold occurs mainly as coarse- and medium-grained particles. Minute inclusions and submicroscopic gold usually account for a minor portion. In contrast, gold in refractory sulfide ores occurs mainly as minute particles and submicroscopic gold, and microscopic gold usually accounts for an insignificant portion. In gold ores containing carbonaceous material, the preg-robbing nature of carbonaceous material may impose challenges on gold extraction and cause gold losses. To extract gold from refractory sulfide ores, the ore needs to be finely ground and preoxidation is often required. Sulfide host minerals must first be oxidised to create a porous structure through which the cyanide leach solution can penetrate to reach the colloidal gold particles. The oxidation is traditionally achieved by roasting, autoclaving or bacterial oxidation. In carbonaceous sulfide ores exhibiting a preg-robbing nature, the carbonaceous material needs to be treated by roasting, autoclaving or other means to minimise the preg-robbing effect. As a predictive and troubleshooting tool, the gold deportment study plays an important role in gold metallurgy. It determines the deportment of gold in an ore or mill product and identifies the mineralogical issues that may affect or may have affected gold extraction. The information acquired from a gold deportment study can be used to assist in process selection, flow sheet development, recovery improvement and reagent optimisation.CITATION:Zhou, J, 2013. Deportment of gold in sulfide ores and implications for gold extraction, in Proceedings World Gold 2013 , pp 433-442 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

It is possible to closely simulate the product sizing distribution from an industrial rod mill by the correct choice of parameters in laboratory batch milling. For laboratory batch rod milling, changes in per cent critical speed and per cent rod volume cause the product sizing distributions to move in parallel at a constant slope. For ball milling, larger sized media in batch milling grind more coarse material giving a closer simulation to the industrial rod mill product. Changing the feed size distribution by removal of coarse particles or addition of fine particles changes the product sizing distribution, but would not normally be practiced in laboratory testing. These data should be applicable to many instances where laboratory simulation of an industrial product size distribution is required.

Jan 1, 1998

By Bidwell TJ, Servant S

Paste back-fill technology is gaining rapid acceptance in the Canadian mining industry. The authors were able to work on four different mining sites employing paste technology in their operation. In each site the paste hackfll is prepared with very fine tailings containing significant amounts of sulphur minerals. The research program involved laboratory testing on samples prepared in the laboratory, on control samples obtained at the hackfilll plant during pouring into the stopes and on core samples obtained from drilling in backfilled stopes. The laboratory testing provided detailed knowledge of the mechanical behavior of the paste backfill. The need for a means of measuring the in-situ mechanical properties of the backfill became clear. A review of various trials published in literature and an evaluation of available technology suggested the Cambridge Self-boring Pressuremeter. A first field campaign confirmed the efficiency and dependability of this instrument leading to the conclusion that it offers a very good method for the in-situ measurement of paste backfill properties.

Jan 1, 1998

By W. M. LONIE

Address by the President of the Institute (Mr W M Lonie) in making the presentation of the Certificate of Honorary Membership to Sir Ian McLellan, K.C.G.M, K.B.E. Address by Sir Ian McLellan after accepting the award.

Jan 1, 1979

Ok Tedi Mining Limited has recently completed the first phase of a trial to compare the performance of D26B Krebs cyclones in different configurations to the new Warman 650 mm CAVEX cyclones. From 1992, rougher flotation feed size has increased from the target d80 grind size of 150 ¦m with increasing SAG mill throughput. At high SAG mill throughput, operators have difficulty maintaining the target cyclone feed pressure and must increase the cyclone feed density, thus resulting in a coarsening of the cyclone split. Warman International have developed the CAVEX high capacity cyclone. The new CAVEX cyclones, when compared to the Krebs units appear to:produce a measurable increase in volumetric flow for the same pressure drop; maintain or decrease the proportion of coarse particles reporting to overflow; and lower the overflow density. In all plant trials to-date, the CAVEX cyclones appear to be superior to the standard Ok Tedi Krebs cyclones. Further testwork is planned to evaluate modified Krebs cyclones (with recent design improvements) against the CAVEX cyclones.

Jan 1, 2000

By N Guresin, R Dunne, S Blanco

This paper presents the results of research work conducted to assess if aqueous solutions of sulfur dioxide (SO2) can be used to treat roaster calcine leach residues such that recovery of gold in this material can be achieved with subsequent application of the thiocyanate (SCN-) leaching system. The project is mainly aimed at assessing an alternative use for sulfur dioxide gas generated during flotation concentrate roasting. The calcine leach residue sample used in the study contained 2.56 g/t gold. The reason for this high level of residual gold is thought to be due to gold surface passivation by thin iron oxide films, presence of gold in solid solution with refractory iron oxides and encapsulation of gold in the structure of these iron oxides.The study was conducted in three stages. The first stage was the characterisation of a sample from a roaster calcine leach residue. The second stage in the project was a set of leaching tests to assess the feasibility of using aqueous solutions of sulfur dioxide to reductively dissolve refractory iron oxide mineral phases contained in the calcine. The final objective was to assess the efficiency of thiocyanate, a gold complexing ligand stable under acidic and oxidative conditions, to extract gold liberated during sulfur dioxide leaching.The study showed that the reductive sulfur dioxide treatment of the calcine leach residues followed by oxidative thiocyanate leaching to extract gold was not a particularly efficient process as only around 20 per cent gold could be extracted. Leaching the calcine residues by any of these systems separately also extracted the same amount of gold (12 - 14 per cent) implying that irrespective of the solution potential, the acidity helps dissolution of gold encapsulating minerals, mostly hematite, but at a very slow rate. The findings on the topic in the literature and during this study show the requirement for further technical investigations and economical analyses on two cases. The first case is to roast gold concentrates to produce magnetite rather than hematite followed by sulfur dioxide and thiocyanate leaching of magnetite containing calcines. The second case is to apply a magnetic concentration process to conventional roast-cyanidation calcine residues to produce a gold-rich magnetite concentrate that can be further treated with sulfur dioxide followed by thiocyanate leaching.For both cases, the best evaluation of the sulfur dioxide leach system in extracting residual gold from calcine leach residues will require a detailed economic analysis to find out the balance between the value of the gold recovered and the loss of revenue from acid production. There are a number of roasters that do not produce acid. In these cases, a portion of the unwanted sulfur dioxide gas can be used to recover gold in magnetite containing calcines as an economic incentive.CITATION:Guresin, N, Blanco, S and Dunne, R, 2013. Leaching roaster calcine leach residues with aqueous solutions of sulfur dioxide and thiocyanate, in Proceedings World Gold 2013 , pp 129-136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By I R. Souza

At the mining industry, there are several uncertainties that may affect the mobile mining equipment fleet sizing and usage, such as commodity supply and demand, which impacts the mineral price, environmental licenses to allow operations and strategic decisions made by the own mining company. Due to that, it may happen to acquire a mobile mining equipment for a specific site and before it finishes the entire forecasted life cycle, the machine gets idle on that operation and a decision must be made regarding this matter. On large mining companies with several sites, equipment transfer provides a good solution to solve this issue and at the same time it provides operational flexibility and allows to use the equipment until the initially planned working hours. This article presents a method to compare technically and financially whether it’s more feasible to transfer a used equipment or to buy a new one. In other words, we will compare a brand-new machine versus a used one in terms of safety, net present value (NPV) considering both capital expenditures (CAPEX) and operational expenditures (OPEX), technological obsolescence, risks, equipment maintenance reliability and lead times. Although it’s not the main purpose of the paper, it will also be briefly discussed the importance of having a considerable amount of backup equipment to handle low likelihood and high consequence risks that may materialise. This backup equipment portfolio is particularly important to avoid loss of sales and profits in case the production plan changes and it demands further equipment than initially planned to cope with the forecasted production.

Nov 8, 2021

Jan 1, 2004

By Zani J. A, Jackson W. D

Bauxite was discovered in the Kimberley in 1965 by an Amax field crew. Reserves of 230 million tons, of bauxite. averaging 47% total alumina on Mitchell Plateau and 980 million tons averaging 36% total alumina on Cape Bougainville have been indicated by the results of drilling and bulk sampling. Laterite which contains the bauxite deposits caps basalt and interbedded sandstone and siltstone of the Carson Volcanics formation. Bauxite on Mitchell Plateau is 3.2 metres thick on average and is underlain successively by nodular ironstone, clay and basalt. The major components of the bauxite are gibbsite,boehmite, hematite and goethite containing some alumina, anatase and clay minerals. Quartz and vanadium oxide are minor constituents. Boehmite and hematite are concentrated near the surface, whereas gibbsite and goethite predominate at depth. The bauxite profile consists of ferru- ginous, pisolitic and gibbsitic zones with increasing depth. Cape Bougainville bauxite is 8.6 metres thick on average and of tubular structure; its mineralogy is relatively uniform..

Jan 1, 1973

By R Jacobs, J Yeates

"The Stockman base metals project is situated in State Forest in the alpine area of East Gippsland, Victoria, adjacent to a National Park and within the headwaters of a major Ramsar-listed wetland catchment and the Murray-Darling River system. Site topography is steep, and elevated (650 m – 1200 m above sea level), and subject to circa 1 m annual rainfall, with occasional winter snowfall. The project consists of two volcanogenic massive sulfide (VMS) deposits to be mined by underground methods and treated in a 1.0 Mt/a central concentrator to produce copper and zinc concentrates for export over a ten year operational life. New resource projects are rare in Victoria. Recognising the sensitive setting, planning for the Stockman Project, which is now in the advanced permitting stage, has focused on balancing economic, environmental and social outcomes to ensure social licence to operate is secured and can be maintained. This has involved close attention to triple bottom line (TBL) risks and outcomes. Stockman has successfully gained State and Federal approvals via the Environmental Effects Statement process. The process of obtaining these approvals has required close attention to effective stakeholder involvement, and management of a lengthy and difficult approvals process, which is still to be finally concluded. This paper is a case study of the process of that permitting and the issues encountered to date. Key learnings from the experience have included: successful approvals require close attention to much more than just the project and its technical aspects and physical setting – effective stakeholder involvement and endorsement is critical the differing consultation requirements for local, regional and government stakeholders, to design and plan implementation of a project to meet TBL objectives, and to gain social licence to operate within the Victorian approvals process, the need for an effective lead government agency with policy authority dealing with material policy change requiring post-closure financial sureties estimating realistic permitting time and cost during the project evaluation phase. CITATION: Jacobs, R and Yeates, J, 2016. Stockman base metals project – sustainability, social licence to operate and permitting lessons learnt, in Proceedings Project Evaluation 2016, pp 98–110 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By A Morris

The Express Rail Link (XRL) will provide high-speed rail services from Hong Kong to Guangzhou and a connection to the national high-speed passenger rail network serving major cities throughout Mainland, China. The HK$ 67 B (NZ$ 11.5 Billion) project is of great strategic importance for Hong Kong and is being implemented to a very tight schedule, from early 2010 with completion targeted for 2015.The works include a 15 platform terminus station in West Kowloon, 26 km of twin track tunnels from the terminus to the Hong Kong/Shenzhen boundary at Mai Po, tunnel vent shafts/adits/emergency rescue siding and a stabling siding facility. Trains on the Hong Kong section are intended to operate at speed up to 200 km per hour and up to 350 km per hour on the Mainland section.This presentation will provide an overview of the entire XRL project, with a focus on the challenging geotechnical and spatial constraints on the tunnel works. This is an abstract only. No paper was prepared for this abstract.

Mar 8, 2011

There is no doubt that the mining sector is considered to be the backbone of many countries. Furthermore, it has played an important role in the prosperity of nations, whether developed or developing. Saudi Arabia is one of these countries that has a large variety of metallic and non-metallic mineral resources that range in size and value occurrences of limited potential to deposits large enough to sustain profitable exploitation. Therefore, the Saudi government needs to reinforce the capacity of the sectoral institutions to better regulate and promote the sustainable development of the sector. The ability to overcome the administrative and legal complications that constrain private sector participation in the minerals sector, through new mining code which will streamline the procedures for obtaining licenses and will add more predictability and transparency to the application process, are proposed for increasing the sustainable development. This paper will outline how the Saudi government is tackling the major challenges that face the minerals industry. This paper provides the background to the Saudi Arabian mineral sector and its industrial base. Finally, the paper identifies the problems and constraints that face the minerals sector in Saudi Arabia and provides an assessment of the effects of government policies and planning efforts in the minerals sector, particularly during the period of the development plans which started in 1970.

Jan 1, 2009

By Greenwood-Smith R, Ellis W. K

A bulk analyser based on the gamma-ray resonance scattering process can be used to give a rapid and accurate measure of the percentage by weight of copper or nickel averaged over a large mass of sample, typi- cally 20 kg. It is shown that for a bulk sample containing about 3 wt.% Cu, crushing to -25 mm is the only sample preparation requited for analysis to within an error of about 0.06 wt.% Cu (errors quoted are one standard deviation). A comparison of bulk analyser and con- ventional assays on the same bulk samples can be used to estimate the sample preparation errors in the conventional methods. The squared deviations between bulk analyser and conventional assays are approximated by the sum of variances in sample preparation, conventional analysis, and bulk sample analy- sis. The sample preparation error was esti- mated as 0.26 wt.% Cu for samples crushed to -2 mm before splitting, 0.08 wt.% Cu for samples crushed to -0.35 mm before splitting, and 0.04 wt.% Cu for the average of 15 grab samples from bulk samples which had been crushed to -2 mm. The average copper grade for each group of samples was about 1.7 wt.%. Results are presented which show that

Jan 1, 1976

By Adams R. W

A commercial scale strong acid leaching plant was commissioned at the Risdon plant of the Electrolytic Zinc Company of Australasia Limited, a member of the Pasminco group of companies, in February 1988. It was designed to upgrade the lead/silver residue product from 26% to 37% lead, thus improving the realised value and increasing overall zinc recovery. This in turn enables the lead smelter treating the lead residue to improve its productivity. The equipment consists of two 250m3 bricklined leach tanks and two 6.5m diameter stainless steel high rate thickeners operating with counter current washing at 95¦C and 120 g/L H2SO4. The present filtration and drying equipment is also being replaced. Two 35m2 squeeze action filter presses equipped with horizontal plates are being installed, together with ancillary drying equipment to ensure that the final product complies with the transportable moisture limit. The new filtration plant is due to be commissioned in mid-1989.

Jan 1, 1989