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By D Cohen, A Wurster

Many Southern African mining operations produce mine water which is beneficially and productively utilised on the mine sites and to support other water uses. Mine water treatment typically takes place within the context of integrated mine water management involving pollution prevention, waste minimisation, recycling and reuse as well as river discharges. Development of new and improved mine water treatment has focused on the neutralisation of metals removal, desalination of high sulfate waters and passive treatment. Mine water neutralisation processes now incorporate a combination of natural limestone and lime treatment, as well as features to maximise gypsum precipitation. The South African CSIR developed a suite of limestone-based neutralisation processes, which include reuse of CO2 and CaCO3 generated in the process. Desalination of high sulfate mine water is typically done using one of the following technologies:biological sulfate removal with different approaches to the handling of the sulfide generated in the process, and ultrafiltration (UF)/reverse osmosis (RO) treatment with different approaches to the handling and disposal of the brine. The current research and development focus is the separation and recovery of saleable products from the treatment residues and brine streams.

Jan 1, 2006

White Cliffs Opal Field is situated in the Parish of Kirk, County of YulguIgra, New South Wales, about sixty miles from Wilcannia, and the River Darling. It is near the southern edge of the cretaceous basin of the interior of Queensland, New South Wales, and South Australia. Twelve miles south-west of the field, at Tarella station, a well sunk at the homestead reached silurian slates at about 127 feet, getting no water but about three miles north-west from the originally discovered and no central portion of the field, a well was sunk by the Momba, Pastoral cmpany, to a depth of 270 feet all the way through the cretaceous beds. At 250 feet a small supply of water was struck, but so much mineralised as to be quite useless. The temperature also was so high that a man could not keep his hand in it and Mr. Hogarth, the Momba Pastoral Company's manager, informs me that so corrosive was the action of the water, that a shovel left down the well for a fortnight, at the time of sinking, was completely eaten away.The well having now fallen in, I have been unable to obtain any of the water for analysis.The western termination of this portion of the cretaceous basin is situated about twenty miles from the present opal field, at which distance the slates, with (probably) devonian sandstones and quartzites resting unconformably thereon, commence to appear. The opal bearing country, as far as at present known, follows a more or less well defined line running north and south towards the northern end of the field, and north-east and south-west towards the southern extremity.

By A Stasi, B Brice

Water is a limited and precious resource in Australia. Because of the increasing demand for water from all sectors of the economy and the variability in supply, efficient management of water resources is of vital importance. The national water reform agenda has provided a strong impetus to all states and territories to progressively move towards more efficient and sustainable water management. The Queensland Water Act 2000 is the legislative framework for providing water for the environment and for planning for the security of supply to water users. The comprehensive water planning process prescribed in the Act results in new tradeable water allocations that are separate from land. These water allocations are well specified and can be traded on a permanent or temporary basis. Trading of water allows it to move to its highest value use, thereby encouraging the most efficient distribution of this limited resource. In addition to transferring ownership of water allocations, it is also possible to change the attributes of the allocation, such as the location from which water may be taken. Changes to water allocations are subject to approval from the resource manager. Pre-testing allows for certain changes to be approved very quickly, making the trading process more streamlined and cost effective. Temporary trades, or seasonal water assignments, currently account for the majority of water trades in Queensland. However, permanent trading activity is expanding steadily as old water entitlements are converted to tradeable water allocations and as the market matures. The permanent trading market provides significant opportunities to the mining sector. It allows mining companies to buy water allocations at market prices without compromising environmental outcomes or causing third party impacts.

Jan 1, 2006

By R B. Wanty

Historically, most investigations of biogeochemical cycling in acid rock drainage systems involved synoptic sampling over longer time periods (one sample per week or month) or intensive time series studies over a few hours or days. However, many important episodic loading events, such as seasonal meltwater and storm events occur on timescales that are rarely observed by these traditional sampling approaches. Monitoring these transient processes, which may contribute the bulk of the annual metal loading, is essential for accurate assessment in acid rock drainage areas. Recent work also has demonstrated dramatic diel (24 hour cycle) variations in trace metal concentrations in response to diel changes in temperature, pH, oxygen, and photochemical cycling (Brick and Moore, 1996; Nimick et al, in prep). To characterise a system that may respond to diel, seasonal, and episodic events, a monitoring program must sample at a frequency that captures the details of these major forcing events. We developed two novel instruments, the Zn-DigiScan and the DigiSampler to examine low and high frequency temporal changes in acid rock drainage areas. The Zn-DigiScan is a battery powered real time in situ chemical analyser designed for long-term deployments with hourly analyses of Zn. Stream physical parameters (temperature, conductivity, dissolved oxygen, pH, turbidity, etc) were measured every 15 minutes with a water quality sonde. The DigiSampler was developed for the long-term daily sampling of biogeochemically active elements and can take either discrete samples or samples integrated over 24 hours. The DigiSampler collects 2 ml samples in a Teflon coil which are separated by 0.2 ml nitrogen bubbles. The sample coil is returned to lab and the 2 ml samples are diluted 1:10 and analysed for trace metals by ICP-MS. Initial results from a three-day deployment at Fisher Creek, MT, USA have successfully demonstrated the ability of the Zn-DigiScan to record Zn concentrations at levels below 100 ¦g/L. Zinc concentrations measured at 30 minute intervals in Fisher Creek showed a diel cycle with low values of ~25 ¦g/L in the late afternoon and increasing to ~60 ¦g/L by early morning. Zn concentrations were inversely related to temperature and pH, suggesting that temperature and pH dependent adsorption was the main factor controlling diel Zn fluctuations. Initial deployment of the DigiSampler also was successful, revealing diel cycles in Zn, Cu, and Mn. Comparison of trace metal samples collected by the DigiSampler showed good agreement with samples collected by an Isco automated water sampler, demonstrating that the DigiSampler can collect clean samples for trace metal analysis at the low ¦g/L range.

Jan 1, 2003

By L Torckler, J Hobbins

Favona is a blind low-sulfidation epithermal vein deposit in the Waihi Vein System approximately two kilometres east of the world class Martha Hill deposit that has produced nearly 6.8 M oz Au to date. The Favona epithermal system has surface expression in variously altered and mineralised hydrothermal eruption breccias forming a series of low hills that are windows through post mineral dacites and ignimbrites. The tip line of the Favona vein is about 50 û 100 m below surface with a steeply east dipping principal vein structure carrying numerous hanging wall splays in the upper flatter section and thickening down dip where the vein steepens. Host rocks comprise feldspar phyric andesite flows with minor pyroclastics. Although Favona has a strike length in excess of 1000 m and vein widths up to 25 m over a vertical range in excess of 400 m it was only recently discovered after nearly thirty years of exploration by various companies involved in the Martha Hill joint venture that operates the Martha Mine. Since discovery in 2001 a feasibility study based on 27.5 km of diamond drilling in 83 holes has been completed reporting a reserve of 1 Mt @ 10 g/t Au against a resource of 1.8 Mt @ 10.3 g/t Au. Exploration is continuing with a further 20.5km of diamond drilling completed to date on nearby prospects.

Jan 1, 2004

By Mingmin Dou

The behaviour and deportment of indium during the precipitation of sodium jarosite from Fe2(S04)3 - Na2SO4 solutions were investigated. Indium is readily precipitated with sodium jarosite, and the extent of In precipitation increases as the In concentration of the solution increases. It was shown that In 3+ substitutes for Fe 3+ in the jarosite structure to form a nearly ideal solid solution series. On a molar basis, the precipitation of Fe is slightly favoured over that of In, and the difference is reduced as the pH increases. Sodium jarosite precipitation becomes kinetically rapid at temperatures >70¦C, but increasing temperatures in the range 70 to 150¦C affect neither the relative precipitation of In and Fe nor the composition of the jarosite product. Low Na2SO4 concentrations result in reduced product yields and jarosite precipitates in which H3O' > Na+. The hydronium-rich precipitates have reduced In contents. Increasing the ZnSO4 concentration of the solution slightly increases the quantity of jarosite formed and results in the incorporation of -0.3 per cent Zn in the jarosite structure. Otherwise, the presence of ZnSO4 has no significant effect on the composition of the jarosite. Seeding accelerates the rate of jarosite precipitation but has a negligible influence on the deportment of In. The jarosite precipitation reaction at 98¦C is relatively rapid and near-steady state conditions are achieved in - 6 h even in the absence of seed. The initially precipitated jarosite is slightly enriched in In with respect to Fe. The ferric ion concentration of the solution has a significant influence on both the amount of jarosite formed and its composition. In particular, the jarosites precipitated from dilute Fe3+ media have significantly enhanced In contents. Hence, it may be possible to recover - 25 per cent of the dissolved In, at the 1000 mg/L level, in a jarosite precipitate assaying - ten per cent In by the controlled oxidation-precipitation of sodium jarosite from a ferrous sulphate processing solution.

Jan 1, 1993

By G MacDonald, B Forsyth, D Corkery, T

An investigation was carried out at Diavik Diamond Mines Inc (DDMI) to identify and quantify the mechanisms through which ammonium nitrate (AN) was entering the mine discharge water. The goal was to develop and complete an investigation of the potential AN loss mechanisms in order to assess their contribution to ammonia in the mine water system. The initial phase of the project involved the collection and analysis of blasting and water quality data that were used to determine the mechanisms by which the ammonia enters the mine water system and to establish a baseline data set for comparison with results from future trials designed to reduce AN loss. Three potential options for reducing AN loss were identified through the first phase of the project. The second phase of the project involved conducting a series of monitored trials with changes made to the drilling and blasting process. The results of these trials were compared to the baseline data set to determine if the changes introduced for the trials had reduced AN losses while producing satisfactory blast results. This paper describes the process for the collection of the baseline data, provides an analysis of the resulting data, discusses the changes made to blasting operations in order to minimise AN loss and describes the results observed subsequent to these changes.

Jan 1, 2007

For the past 40 years, underground trucking using diesel powered or electric wheel driven vehicles, either conversions of surface trucks, or purpose built, has been the preferred means of ore and waste transport in underground mining. The relatively low capital cost, flexibility and requirement for minimal infrastructure means that trucking systems are selected in the early stages of a mining operation. An increase in the carrying capacity of trucking systems with dimensions to operate within existing development excavations is the solution to long term ore and waste underground haulage systems using trucks. The next generation of underground trucks will be low profile articulated trucks with carrying capacities up to 60 t.

Jan 1, 1998

By L M. Zhang, T H. Xu, J Zhao

Blasting is one of the most commonly used strategies for excavation in civil and mining engineering. Yet blasting can also bring along such undesirable effects as ground vibrations and soil disturbance. Numerical analysis is a powerful tool for estimating the effects of blasting and improving blasting design. In this research, a constitutive model for sand is proposed for the numerical analysis of blast-induced ground motions and wave propagation in soil mass. In the model, three model surfaces, ie the critical surface, the dilatancy surface and the bounding surface, are defined following the bounding surface hypoplasticity framework. The strain rate is included explicitly into the model formulations so that the proposed model is valid under high strain rate loadings caused by blast-induced vibrations. The performance of the proposed model is validated by the simulation of drained triaxial compression tests conducted on a crushed coral sand under different strain rates.CITATION:Xu, T H, Zhang, L M and Zhao, J, 2014. A bounding surface model for sand subjected to blast-induced vibrations, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 201–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By Cai S, Zhou C

The requirement of mineral resources is increasing as the economy is continually increasing in China. The mining practices of various complex sulphide deposits and precious metal deposits, and the treatment of mine tailings and other industrial solid wastes, have greatly improved fill quality in the metal mines. From early-1980s, high density slurry fill, paste fill of total tailings, low density slurry fill with addition of silicate gelling agent, etc has been studied and applied, and some progress has been achieved. Today, mine tailings, slag and power plant ash are widely used as fill materials in mining. A number of cemented fill mines equipped with large capacity trackless mining machines are in production. Recently, The 3rd Chinese National Symposium on Mining with Backfill, 1995 has been held, the progress of fill technology in mines has been exchanged and summarised. In the paper, some aspects of fill technology used in the metal mines of China are briefly introduced and some applications of fill research work are presented.

Jan 1, 1998

By R Wei, Y Peng

With the depletion of high-quality ores, the efficiency of extracting difficult gold ores through flotation and leaching becomes very important in the mining industry. Iron contaminants, sulfide and carbonaceous coatings on the surface of gold and gold bearing minerals significantly hinder the recovery of gold during gold processing. As the surface of gold minerals is easily contaminated, coatings of iron oxides and iron hydroxides originated from the grinding process and oxidation of iron sulfides will cause a retarding effect on both gold flotation and leaching.To mitigate the processing issues caused by undesirable surface coatings on gold minerals, a new technology in treating surface coatings of iron contaminants has been developed. The pulp potential and pH of the slurry are altered to allow dissolution of surface coatings which are further excluded by the use of complexing reagents. The current work shows that iron contaminants can be removed from the surfaces of gold through Eh-pH adjustment and chelation which result in significantly improved gold flotation response. The addition of complexants aids the formation of iron chelates to prevent the iron species in the solution from forming iron oxide and iron hydroxide in the flotation conditions.CITATION:Wei, R and Peng, Y, 2014. Mitigating the effect of surface coatings on gold processing, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 187–192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

It is a well known fact that the best method of rock reinforcement is to avoid physical ground support. This goal can be achieved by means of: - Increasing the rock structural strength - Geological definition and forecasting. - Sequencing the excavation - Smooth blasting In many cases however, extra ground support is needed in order to maintain safe working conditions. In an open pit, the structural strength of rock cannot be increased by lowering the pit walls due to economical reasons. Economy demands steeper walls and less waste to be hauled to the dump. The geological conditions can also often be extremely poor and unpredictable. For excavation sequencing and smooth blasting there are good possi- bilities, such as cleaning of the pit walls after the main excavation, arul- ing of long small diameter straight inclined holes, use of smooth blasting techniques and lightened explosives.

Jan 1, 1989

In the future to excavate sufficient coal for power generation, two dredgers would be required to dig overburden or interseam 70010 of the time and three dredgers 40010 of the time. One overburden system was not adequate for this requirement, making coal production reliability vulnerable. TS5 spreader is the new machine element of this system. The selection of the best type of machine configuration to suit the application was then subject to an internal SECV VE Study, a registration of interest and a tender for two machine alternatives. This paper outlines the reasons why SECV planned the Secondary Overburden System and how the Krupp machine met these requirements. It also identifies the main design features of the machine and its constructability which will allow the machine to be operational by the end of May, 1990.

Jan 1, 1989

Grade control aims to deliver quality tonnes to the mill via accurate definition of ore and waste. It comprises data collection and interpretation; local reserve estimation; supervision of development and mining; and stockpile management. The foundation of all grade control programs should be that of high quality sampling supported by geology. The requirement for quality grade control samples has long been recognised, where they should be representative, unbiased, safe and operationally timely. Underground sampling methods include chip and channel samples; grab samples; and drill-based samples. To achieve quality samples, collection techniques employed should minimise delimitation, extraction and preparation errors. Grade control staff should be well-trained and motivated, and mining staff should understand the need for grade control. This paper reviews grade control sampling methods and presents recommendations for best practice and minimisation of sampling errors.

Mar 1, 2010

By R Higashi, D Maruoka, T Murakami, Y Iwami

The ironmaking industry consumes a large amount of fossil fuel derived carbon as heat source, reducing agent of iron ores and carburising agent of reduced iron. Although the demand for drastic decrease of carbon dioxide emission, carbon is an essential element for smelting process of molten iron. The carbon recycling ironmaking process by circulating CO has been already proposed to achieve carbon neutrality. However, the production of molten hot metal is not considered in this process because sufficient amount of carbon does not dissolve in reduced iron by CO. Therefore, our group has suggested a new carbon recycling ironmaking process which can produce hot metal. In this process, free carbon and iron carbides produced by carbon deposition reaction using metallic iron as a catalyst are used. It is known that only Fe3C is obtained as iron carbide by using CO gas, however, Fe5C2 is also produced by adding H2 gas. The composite agglomerated with these carbonaceous materials and fine iron ore (Deposited Carbon-Iron oxide Composite: DCIC) is reduced and melted in a furnace. It is reported that Fe3C in DCIC accelerates the reduction reaction and melting of the composite. In this study, the effects of iron carbides and free carbon on the melting behaviour of DCIC are investigated. Fe3C, Fe5C2 and free carbon were produced by vapour deposition using porous iron whiskers and CO-CO2-H2 gas. These were agglomerated with hematite reagent at a certain ratio to prepare DCIC samples with and without Fe5C2. The samples were heated up to 1300°C in inert atmosphere. The DCIC containing Fe5C2 completely melted and iron nuggets were obtained after the experiment. This behaviour was not observed in the composite without Fe5C2. This indicates that using Fe5C2 is more preferable than Fe3C for molten iron production using DCIC.

Jun 19, 2024

By Merritt RR

The equilibrium phase relations in the Fe- Mn-Ti-0-S system were established at 1380 and 1485 K. The elemental distributions between the equilibrium phases were obtained by chemical- ly analysing selected samples from the phase study. The results are considered in relation to the coal reduction process for upgrading ilmenite. The beneficial effect of adding sulfur to a kiln that uses a manganese-rich feed is ex- plained by the formation of a metal-sulfide solid-solution phase that removes part of the manganese from the oxide system. The optimum conditions for operating the reduction kiln are determined, and the practical need to operate the kiln at other than optimum conditions is explained. It is shown how the experimental data can be used to predict the best compromise conditions for reduction and the resultant purity of the product.

Jan 1, 1980

The mineralogy, maero- and micro-textures of Thackaringa ore are simple and have many counterparts among base metal-quartz-siderite vein type deposits elsewhere.The ore consists predominantly of galena, sphalerlte, chalcopyrite, tetrahedrite, and arsenopyrite in a quartz and siderite gangue. Silver minerals, as such, appear to be lacking and silver values are no higher than in other sulphide ores of this type. These features contrast very markedly with those of the A.B.H. Consols Lode which appears to have emanated from the north end of the Broken Hill Main Lode Horizon during high grade regional metamorphism. The Consols Lode has been regarded as of Thackaringa type, and both are regarded as possibly arising from the remobilization of Main Lode Horizon ore. Whilst this may yet prove to be so it appears that the marked differences in mineral composition between the Consols and the Thackaringa types, would require somewhat different modes of regeneration.Thackaringa ore, as well as A.B.H. Consols ore, on this basis, would necessitate the development of a metahydrothermal ore fluid to account for their present apparently hydrothermal (or pseudo-hydrothermal) constitution...

Jan 1, 1967

By Eren H

For a hydrocyclone of fIXed geometry, DC, Di, DO and ? are constants, the variable parameters affecting the performance are Qi, Fi, Du and H. (See Appendix 2 for definition of symbols).The relationship between d50c, Qi, Fi, Du and H gives models which can effectively be used for performance predictions. Such models have already been established by Lynch et al and by Plitt.These models have been tried in a limited manner under continuous operating conditions for on-line cowol. For on-line control effective and accurate instrumentation is required for which a new set up is proposed. Using this set up, a new model was established. A feature in this model is that deviations from the norm of operational parameters affecting d50c were considered. It is shown that these deviations generated by the disturbance of one or more of variations in the parameters, can be monitored by a computer and suitable signals generated to control servo mechanisms for restoring the required d50c value.The logic followed in developing the computer software is described and the application of the model is indicated.

Jan 1, 1990

By T Leach, I Pringle

The Bowdens Silver Deposit is a low sulfidation epithermal silver-base metal deposit that has formed on the northern margin of a hydrothermal system within air-fall breccias, ignimbrites and crystal tuffs of rhyolitic composition. The deposit lies near the north-eastern margin of the Lachlan Fold Belt and the rhyolitic host rocks are of Early Permian age. The silver mineralisation occurs as flat-lying zones of disseminations and silicic fracture-filling within the Rylstone Volcanics and is closely associated with sulfides of iron, arsenic, lead and zinc. High-grade silver mineralisation is also found in steeply-dipping fracture zones which host banded sulfide veins. Studies of the alteration products indicate that high temperature fluids, flowing from south of the current project area, resulted in quartz (¦adularia) û illite/sericite alteration. Cool, low pH steam-heated waters on the northern and eastern margins of the prospect area resulted in siderite û smectite-illite clay û Fe-carbonate û marcasite û kaolinite alteration. Mixing of the two fluid types resulted in the deposition of iron and base metal sulfides, a decrease in both sulfur activity and pH of the mineralising fluid, and subsequent silver mineralisation.

Jan 1, 2004

By V S. T Ciminelli

This work aimed at evaluating the acid rock drainage (ARD) potential of five samples of a Brazilian gold sulfide mine in a decommissioning process. Three of the most traditional ARD prediction techniques, Standard Acid Base Accounting (Std ABA), Modified Acid Base Accounting (Modified ABA), as static methods, and humidity cells as a kinetic method were tested. Both the Std ABA and the Modified ABA results indicated an acid generation potential for some of the studied samples. In the other cases the results were inconclusive. The five samples were then submitted to humidity cell tests during 27 to 30 weeks. At the end of the period, the leachate pH was stabilised in a range from 3.4 - 4.1 (four samples) to 5 (one sample). The presence of relatively high levels of sulfate and dissolved metals was detected throughout the operation, specifically, Ni and Zn, and less frequently, As. These findings are discussed with the help of the samples mineralogy and Eh-pH diagrams. The results obtained in this investigation indicated potential environmental risks of this mining area. In this particular case, the kinetic tests were shown to be essential to the identification of the samples ARD potential.

Jan 1, 2003