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This paper addresses, in particular, the influence of winding depth on the selection of head ropes for Koepe winders. Because this is just one aspect of winder design that affects the operational safety of the winding system, the paper starts by considering all the issues governing the life and safety of the winding ropes. Regulations from a variety of countries are reviewed and comparisons of the legislated rope factors of safety and their variation with winding depth are made. This is followed by a discussion of the typical observed mode of in-service deterioration of Koepe head ropes. This mode of deterioration is due to fatigue and is influenced by the load range occurring in the ropes. Parameters contributing to load range are discussed and the influence of winding depth is highlighted. Lessons learned from early experience with very deep Koepe winders in South Africa are recalled. Predictions of load range as a function of depth are made, from which general rope life predictions are made for ropes selected by conventional national factor of safety requirements. This is illustrated in graphs comparing rope life as a function of depth. Typically a reducing life with depth is predicted. A rope selection strategy is advocated, which is based on achieving a constant rope life irrespective of the depth of wind. A new factor of safety (or rope design factor) equation is prepared that has the trend of increasing with depth. This proposed equation is compared with other published proposals that promote an increasing rope factor of safety with depth. It is shown that smoother winder drive controls enhance winding rope life and this improvement is quantified. The paper concludes by pointing out the consistency in predicted and observed life of winding ropes selected in accordance with legislated factor of safety approaches. It recommends the adoption of a new rope design factor equation for rope selection, to be used in conjunction with appropriate codes of practice for winding rope condition assessment and for the design, installation, operation, maintenance and testing of Koepe winders. The new rope design factor equation approaches a limiting economic depth of wind at shallower depths than the existing Koepe factor of safety approaches. However these older approaches æbuild-inÆ a reducing rope life with depth. The new rope design factor is therefore a more consistent way to select Koepe ropes and to evaluate economic trade-offs between Koepe and conventional double-drum or Blair winding systems.

Jan 1, 2005

By Coppock BW

Sintering of lead and zinc concentrates is practised by Sulphide Corporation Pty. Limited to provide both desuiphurised lump sinter feed, for simultaneous reduction to zinc and lead in the Imperial Smelting Process blast furnace, and sulphur dioxide gas for sulphuric acid manufacture. From November, 1969 a 20 percent increase in production rate has been obtained through improvements in operating technique. A gradual increase in bed permeability was achieved by modifications to the feed mix conditioning equipment and by improving moisture control. However advantage could not be taken of the higher permeability to increase sulphur elimination because the hardness of the lump sinter decreased. Higher throughput, better quality sinter and more stable sintering conditions were however made possible by simultaneously: 1. reducing segregation and compaction in the sinter bed, by narrowing the discharge opening of the main layer feed hopper, 2. reducing the sizing of sinter returns to give a closer size spectrum of particles in the feed mix, and 3. increasing the sulphide sulphur content of the feed mix to give higher bed Temperatures.

Jan 1, 1972

By Chaturvedula V. K

Pillar extraction carried out using various methods (split and lift, Wongawilli and Old Ben) involves the formation of narrow fenders (commonly 7 m of coal) formed by driving "splits" for lifting off with a continuous miner. The strata above a split and fender adjacent to the goaf consists of a cantilever beam (usually >3 m thick) that extends from the solid coal and bridges across the fender. Lifting off the fender from the split in safe conditions depends upon the bridging capability of the cantilever and the fender strength. The nature and competence of the immediate and near roof, the support capability of the coal fender and the presence of faults and or joints can adversely affect the bridging behaviour of the cantilever. Insufficient knowledge of these parameters can lead to extraction under dangerous conditions. Remnants of fenders ("stooks") also support the cantilever and their dimensions are critical to obtain regular caving and goaf falls. Stook area, goaf roof span and roof stand-up time after lifting can be related and only a relatively small increase in stook area of 10-15 m2 can lead to a significantly increased stand-up time, especially under a massive roof. Such conditions strongly influence the re- distribution of abutment stresses and can create increased outbye pillar loading. Based on detailed underground geotechnical investigations, it is concluded that strata caveability, roof cantilever behaviour, fender H:W ratio and remnant stook size are all critical parameters for successful and safe pillar extraction.

Jan 1, 1992

By A C. Robertson

Studies by Tennent, Isokangas Pty Ltd (TIP) have indicated that underground quarrying of backfill may be a cost competitive option for providing backfill for specialised situations in underground mining. Situations where suitable bulk fill material may not be available on the surface, and where the total cost of setting up a fill distribution system are prohibitive, could favour the mining of fill material underground adjacent to the stopes being mined. Considerations include environmental impact, scheduling, surface constraints and total costs. The examples quoted in this paper, and the case studies are based on the authorsÆ personal observations and experience.

Jan 1, 1998

In spite of the efforts done in the past to implement in Codelco best practice guidelines and standards on several important sampling, assaying and variability issues, many people, particularly top managers and operators, are still not aware of the relevance of the use of the principles and practice of geostatistics, sampling theory, analytical chemistry and the understanding of processes variability from rock to cathodes. As a result, an important challenge for the sampling community is to find out the causes of this lack of awareness and to develop communication skills to influence the organisation, particularly the top management level. This situation is not affecting only Codelco; it is a common characteristic of the copper mining industry. The main cause is cultural. Judeo-Christian and occidental sciences are deterministic. This implies a disregard of process variation and the assumption that homogeneity is omnipresent. Another important aspect of the cultural challenge is education. Education is the most efficient way to transfer a system of ideas, traditions and practices. To implement proper courses of sampling theory and geostatistics and support to multidisciplinary education at universities, mining companies will improve teamwork between geologists, mining engineers, metallurgists and chemists. The improvements will imply a more sustainable and efficient mining business.

Mar 1, 2010

By Hang G, Hongtian X

In this paper, it is briefly introduced that China's Ordovician limestone confined-water menaces coal mining and Ordovician water is prevented and cured to secure the safety of coal mining. The theory of "Down-Three-Zones" is presented on the basis of research and practice in recent ten years. The concept of "Down-Three-Zones" of floor water-eruption is described clearly. Finally, the principle and method of applying the theory of "Down-Three-Zones" are discussed. 1. An Introduction of Damage: China is rich in coal resources. The conditions of coal field geology are quite complicated. There is an area of two million square kilometre of Karst limestone in nine million six thousand square kilometres of territory. The resources of underground water are rather plentiful, but this menaces coal exploration. Sixty percent of coal mines in China are damaged by limestone confined-water in different scales, particularly coal mines located the Carboniferous-Permian coal fields of the Ordovician limestone distribution area of Northern China. Because there is the 500-800 metre thickness of Ordovocian limestone and the well developed Karst containsl plentiful water, Karst water can have more than 100 Kg/cm pressure. Limestone aquifers have only distances of several metres or several decade metres to coal seam, Karst water can enter the aquituge and even the coal seam, large eruptions often occur. For example, a mine of 3 million ton production capacity had an eruption of 2053 cubic metres per minute. This is the largest confined-water eruption which has brought enormous economic damage and threatened the safe production of coal mining. Therefore, the prevention and cure of Ordovician water has immense advantage to the development of the coal industry. There are several decades experience in the prevention of Ordovician water-eruption in China. The prevention of Ordovician water-eruption has two kinds of plans. 1) dewatering and depression: it refers to dewatering of aquifers as roofs of seam and depression of aquifers as floors of seam in mining areas. 2) comprehensive prevention under the condition of having water pressure in aquiters. Due to enormous water, electricity, equipment and lots of other factors, the former isn't used extensively, the latter tits to China's actual conditions and is used widely. So-called comprehensive prevention under the condition of

Jan 1, 1988

By Medhurst TP, Trueman R, Hutchinson IN

A breaker line support (BLS) monitoring system, BLSmon, has been designed and constructed by the CSIRO and installed and commissioned at Laleham No.] Colliery, Queensland. This system was designed to record hydraulic leg pressure and canopy position measurements and relay these, in real time, to the surface. The system has shown itself to be capable of operating on the BLSs without any adverse affect on production. Analysis of the results of the monitoring exercise has shown that rate of change of leg pressures on the BLSs could be used as an aid in the prediction of adverse mining conditions. Under favourable mining conditions the supports were observed to initially unload from the set pressure, this unloading reduced with time and by the end of a typical lift cycle had either ceased or reversed slightly. This behaviour was considered to be due to one of four possible causes, these being; the compaction of floor debris, and/or compaction of the floor, and/or crushing of the roof and /or support creep. The actual cause can only be determined through detailed monitoring of both roof and support convergence. However observational data would suggest that compaction of debris and softened floor material beneath the supports was the most likely cause. The few positive loading rates recorded under these conditions were of short duration and occurred towards the end of individual lifts. Where mining conditions were unfavourable the negative rates of change of pressure, unloading of the support, were reduced throughout a lift, in both duration and magnitude, when compared with favourable mining conditions. Over the same period the positive rates of change were observed to be greater. The rate of change of loading and convergence can be utilised to identify the onset of instability in the lift area. However, before this facility can be utilised by the mine for the reliable prediction of instability more monitored data and sophisticated processing techniques are required.

Jan 1, 1992

By J T. Woodcock

This paper discusses characterisation techniques that can be applied to complex waste products from metal production and processing operations with the aim of devising treatment methods for upgrading the metal content for recycling. Two waste streams were selected to illustrate the role of characterisation in adapting mineral processing techniques to provide an effective recycling strategy. Waste products chosen were:aluminium dross, which contains metallic aluminium particles in a coarse matrix of many components; and steel shredder sludge that contains copper wire and other metallics in a matrix of plastic and natural fibres, iron oxides, metallic iron, and other compounds. Characterisation methods discussed include chemical analysis (XRF, ICP-AES, and selected specialised techniques), phase analysis (XRD, SEM, TEM, and optical microscopy), morphology (IFESEM), sizing analysis (screening, Cyclosizing, Infrasizing, Malvern sizing), and general techniques such as particle shape, surface area, and porosity determinations. The applicability of these techniques to the waste products is considered in relation to their advantages and disadvantages, and sampling issues.Treatment techniques considered for the two waste products included comminution, screening, air or water classification, simple water leaching, gravity separation, magnetic separation, flotation, and eddy current separation.Tentative flow sheets were developed for the two wastes. For aluminium dross, it was proposed to use fine crushing followed by water washing to remove soluble chlorides and aluminium nitride, and then desliming followed by flotation of the granular fraction to give a metallic aluminium-rich concentrate. For shredder sludge, it was proposed to use wet screening, water classification, and gravity concentration to produce a copper-rich product and magnetic separation to produce a metallic iron-rich product.

Jan 1, 2004

Alfred Nobel first invented a practical detonator in 1863 and then the blasting cap in 1865. At that time the detonator was used on the end of a length of safety fuse to initiate nitroglycerine-based explosives. Since then the detonator has gone through a number of changes. The instantaneous electric detonator was the first to allow remote firing. The electric delay detonator followed and allowed for timing between holes. In the mid 1970s the NONEL« Tube was invented. This tube combined with NONEL« detonators meant that many of the safety issues, such as stray current and radio frequency, associated with electric delay detonators were eliminated. This system gave the mining industry a reliable and fairly accurate system with which to detonate shots of any size. Since the early 1980s a large amount of research and development work has been done around the world to create a more accurate detonator for the mining and quarrying industry. After years of research, electronic detonators have emerged as the most accurate and precise initiation system available to the mining and quarry industry today. Electronics provide the user with millisecond timing accuracy. The improved level of timing control allows operations to improve fragmentation, throw and reduce vibration levels. There are now a number of different electronic detonator suppliers on the market today. In 2004 Dyno Nobel formed a joint venture called DetNet with AECI. DetNet has a suite of electronic detonators: DigiDet«, HotShot« and QuickShot«. This paper will focus on the HotShot« system, the first of the three new initiation systems to be released to the market in Australia by Dyno Nobel.

Jan 1, 2005

By M I. Pownceby, N A. S Webster, J Manuel, N Ware

The properties of iron ore sinter – commonly defined by measures of tumble strength, reduction degradation and reducibility – have a major impact on blast furnace performance. These properties are largely influenced by raw material properties, in particular the bulk ore composition. Despite this importance, there is a lack of quantitative data on the impact of ore chemical composition on iron ore sintering. This is surprising since the levels of Fe, SiO2, Al2O3, P, MgO and other elements, together with the nature of the minerals in the fine ore, play a major role in determining the abundance and type of high-temperature bonding phases that form during sintering. It is the abundance and nature of the high-temperature bonding phase(s) that directly influences sinter quality. This study combines in situ diffraction experiments in model sinter systems with laboratory-based compact sinter tests using natural ores to examine the links between iron ore composition and sintering temperature and their effects on standard metallurgical sinter quality test methods. Results help to establish the critical compositional and thermal parameters that control the bonding phase chemistry, which in turn influences the physical characteristics of the sinter matrix. This information should enable operators to predict optimum sinter operating conditions based on the initial chemistry and mineralogy of the iron ore fines and recognise the chemical modifications to the original iron ore fines required to produce high-quality iron ore sinter.CITATION:Pownceby, M I, Webster, N A S, Manuel, J and Ware, N, 2015. Iron ore geometallurgy – examining the influence of ore composition on sinter phase mineralogy and sinter strength, in Proceedings Iron Ore 2015, pp 579–586 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By D J. A Van Zyl, J C. Cunning

Technological advances associated with the expanded application of paste technology in underground mine backfilling are now stimulating an interest in the disposal of process tailings as paste in the surface environment. Concurrent with the development of alternative surface tailings disposal practices is the requirement to fully understand the consolidation behaviour of tailings in paste form, and to relate this understanding to the significant body of data and operating experience from decades of study of the performance of hydraulically placed tailings. One effective method for demonstrating the benefits derived from handling and placement of tailings as paste is to review tailings slurry consolidation theory from the perspective of the changes which take place in the material as it makes its transition from a loose slurry to a dense, stable deposit resulting from managed thin-layer deposition. For a typical process tailings, an example is provided which illustrates the effect which mechanical dewatering has in accelerating the consolidation process and thereby providing a range of benefits from the perspective of surface disposal. Increased rates of filling (rise), expanded use of upstream embankment construction methods and elimination of impounded surface solutions are some quantifiable benefits which can be assembled on a site-specific basis to allow for valid comparisons with more traditional approaches to tailings disposal.

Jan 1, 1998

By R Justa Cámara, J María Bertrán Llop

"The need for suitable geotechnical characterisation of the rock mass for underground construction is evident. The enlargement project of Railways of the Generalitat of Catalunya (FGC) in Sabadell is a patent example.In general, it is uncommon to encounter problems in the identification and characterisation of certain relevant weak rock formations, which affect project designs. However, all materials should be properly studied, as mischaracterisation can lead to a suboptimal design, resulting in construction problems during the course of the work.Good quality rock is generally not difficult to characterise, but this is not the case for Quaternary or Tertiary cemented soils. Geotechnical investigations based on boreholes do not provide enough information because samples are often badly damaged during the drilling process, if appropriate techniques are not taken. The samples can be altered and may not be representative of the in situ?material.The design and construction of the extension to the FGC line in Sabadell highlighted the importance of the characterisation of Quaternary and Tertiary cemented soils, in particular their rigidity and its underestimation. The twin tunnel project had a total length of 5.1 km, including five stations with 3.5 km excavated by tunnel boring machine (TBM). The remaining 1.6 km was constructed using cut and cover methods. The TBM portion of the tunnel had a bored diameter of 6.83 m with an internal radius of 3 m and 0.25 m thick precast concrete segments. Much of the tunnel alignment passed through and was affected by the presence of certain stiff layers of Quaternary cohesive materials.In this paper the TBM challenges faced will be discussed in detail. In particular:  TBM excavation rate reductions and overheating problems due to the required excessive thrust and torque floating problems in the lining due to nil earth pressure over the rings and the development of an improved, controlled setting time mortar to address this issue block-in and block-out methodology for each station, in some cases with internal blocks to prevent earth pressure drops and soil scouring the relevance of performing simpler solutions, for example, hyperbaric interventions to examine the cutter wheel tools when it has been shown that interventions under atmospheric conditions were equally feasible the implementation of conventional bivalve machines as standard procedure for excavation of diaphragm walls in stations, where in fact, hydrocutter machines or pile boring machines may have been required, given the mechanical characteristics of the materials to be dug out.CITATION:Justa Cámara, R and María Bertrán Llop, J, 2014. Underground extension of the FGC line in Sabadell through cemented soils, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 161–170 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 17, 2014

By B M. H Sharp, R P. Hide, S P. Devine

Uncertainty and debate currently pervade the mining industry in New Zealand. The operational uncertainties, whether external (eg gold prices, the exchange rate), or internal (eg coal expansion difficulties), are large. In addition, many wider factors which influence mining are in a state of flux. State Coal Mines, the operating branch of the Mines Division of the Ministry of Energy I may be made a state corporation, with the remaining Mines Division functions being revamped. The agencies administering environmental legislation are to be restructured. Mining legislation amendments have been proposed and then dropped, and the area is now to be reviewed (The Press, 31 July 1985). Some mining licences have been withdrawn, and become the subject of heated debate in the community (The Press, 19 July 1985, and subsequent letters to the editor).

Jan 1, 1985

By K Knorr, S Birch

The mineralogy of new certified-reference-materials (CRM) for X-ray fluorescence from Western Australia (ASCRM 030 to 035) was analysed by X-ray diffraction using the BRUKER energy dispersive one-dimensional detector LYNXEYE-XE. The samples were studied using standard-less quantitative phase analysis, based on the Rietveld method. This method delivers the relative amount of crystalline phases. All materials were found to be high-grade iron ore predominantly consisting of hematite and goethite and very low amounts of magnetite. In addition, the gangue mineralogy was characterised. It consists of low-per cent amounts of carbonate (siderite/calcite), quartz, kaolinite, chlorite and gibbsite.Furthermore, all samples were analysed with the external standard method. This is an elegant way to probe for amorphous content without adding an internal standard. All six samples were found to contain up to 16 per cent amorphous or nano-crystalline material.CITATION:Knorr, K and Birch, S, 2013. Mineralogy of new Australian x-ray fluorescence standards, in Proceedings Iron Ore 2013 , pp 269-274 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By C W. Davis

Every diesel engine emits approximately 100 million nano diesel particles (nDP) per cubic centimetre of raw exhaust. Each nDP has a diameter of between 50 and 70 nano metres or 1/100th the size of red blood cells (diameter of between 6 and 8 microns). When inhaled, some nDP pass through the lungs and penetrate all body tissue [1]. Europe and North America have recognised and are addressing the long term health problems posed by nano diesel particulate matter (nDPM) across their societies [2.3]. Australia has been slow to recognise the issue, at both a societal and mining industry level. There are chronic health effects for every underground miner and serious legal issues for mining companies with increasingly stringent Occupational Health and Safety legislation being implemented at a state level across Australia. This paper will review progress within Australian society and more particularly the underground hard rock mining industry, particularly in Western Australia (WA).

Mar 15, 2021

By R L. Chaney, M Mahoney

Mine and ore beneficiation wastes and smelter contaminated soils often cause phytotoxicity and threaten adverse environmental effects if not remediated. Science has clarified both the risks from soil metals and methods to alleviate those risks that can be applied at low cost. Phytoremediation is a family of plant and agronomy based technologies to deal with environmental aspects of sites requiring remediation. If valid risk assessment indicates that metals comprise risk, phytostabilisation may be used to alleviate that risk for most contaminated sites. In particular, Zn-Pb, Cu and Ni mine and smelter sites are readily remediated by making the soil calcareous and fertile, with added organic and metal sorbent amendments that include soil microbes to ‘revitalise’ the soil. In each case, the soil fertility and causes of phytotoxicity should be clarified by agricultural soil extractions, and the combination of amendments required to improve fertility and reverse phytotoxicity identified and found locally. In contrast with phytostabilisation, phytoextraction/phytomining uses rare metal hyperaccumulator plants and agronomic management to maximise annual phytoextraction of soil elements into plant shoots for harvest, ashing and use as a metal ore. Plants that accumulate more than two per cent Ni in shoots, and yield 10–20 t ha-1 dry biomass yield 200–400 kg Ni ha-1, which has value greater than all common agricultural crops. Considering the value of elements, existence of hyperaccumulator plants and demonstrated agronomic management for Ni phytomining, it is clear that mine sites and Ni mineralised subore-grade serpentine soils can be phytomined economically as an agricultural mining technology. A team developed agronomic methods and improved cultivars of Alyssum, which can be profitably grown on temperate zone Ni mineralised or contaminated soils. Plant species for tropical ultramafic soil materials have been identified. Phytoextraction is also strongly needed to remove Cd from rice soils to prevent human disease from soil Cd.CITATION:Chaney, R?L?and?Mahoney, M, 2014. Phytostabilisation and phytomining – principles and successes, in Proceedings Life-of-Mine 2014 , pp 3–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

The continuous casting of zinc alloys has been of fundamental importance for many years in the production of a number of products, including sheet for architectural applications, battery cans for dry cells and wire for metallising. The intrinsic benefits of continuous casting, including efficiency and high tonnage capability, uniformity of metallurgical structure and properties, and absence of voids and other defects, have contributed to the success of these products. Less well known, but of growing importance, is the more recent application of continuous casting technology to the production of zinc alloy bar stock products, including bearing stock, machining bar stock, forging stock and cathodic protection anodes. A wide range of zinc alloys are now continuously cast in a variety of cross sectional shapes and sizes to suit the diverse characteristics of these products. Of particular significance are the introduction of hollow zinc-aluminum bearing stock, and the availability of zinc alloy machining bar stock for hydraulic applications and for producing prototypes of zinc alloy pressure die castings. In addition to the traditional benefits, continuous casting provides special properties which are important in the application of these bar stock products. The list of successful applications of continuously cast zinc alloy bar stock is growing rapidly, and the market potential for resultant new zinc applications appears to be significant.

Jan 1, 1993

By Neill A, O&apos

The City of Kalgoorlie/Boulder is situated approximately 600 kilometres to the east of Perth (Fig. 1), and is the major regional centre of the Eastern Goldfields, supporting a population of approximately 25,000. The formation of Kalgoorlie Consolidated Gold Mines in 1989 brought the existing operat- ing entities adjacent to the city under common ownership and management. The Joint Venturers forming the management company are Homestake Gold of Australia and Gold Mines of Kalgoorlie (a Normandy/Poseidon com- pany). This traditional underground mining centre has been worked since 1893, yielding 40.8 million ounces of gold from ore with an average head grade of 10 grams per tonne. Historically the heart of the operation has been the famous Golden Mile located on the Eastern perimeter of the city, in the area known as Fimiston. The other significant operations that form KCGM are the Mt Percy Open Pit and the Mt Charlotte Underground Operation. KCGM's current production is 520,000 ounces per year, with the com- bined Fimiston operations (open cut and underground) contributing 400,000 ounces. The current expansion will increase production levels by a further 150,000 ounces. Traditionally 98 per cent of gold has been sourced from underground areas, however the recent upsurge of open cut operations is rapidly overturning this historical relationship.

Jan 1, 1991

By A D. Strand

The Coeur dÆAlene mining district in northern Idaho, USA is the second largest producer of silver in the world. The Proterozoic Revett Formation hosts most of the mesothermal Ag-Pb-Zn vein ore in the district; it consists of informally designated lower, middle, and upper members. All three members show up to an order of magnitude of southward thickening across the regionally significant Osburn fault. Changes in thickness of the Revett Formation across the Osburn fault reflect a major, down-to-the-south, crustal-scale fault that:was active during sedimentation, was periodically reactivated during the structural and metallogenic history of the district, and likely provided first-order control over regional fluid flow during mineralization events. Where vein structures intersect favourable strata, they produce rich ore; where vein structures cross unfavourable strata, they are poorly mineralised or barren. The most favourable host rock in the district is quartzite, which accounts for the large production from the quartzite-rich Revett Formation.The district has five main types of hydrothermal alteration:feldspar destruction, hydrothermal bleaching, carbonatisation, sulfidation, and silicification. Feldspar destruction is the most extensive and pervasive type of alteration, involving the district-wide absence of feldspar from Belt Supergroup rocks. Hydrothermal bleaching results from the destruction of hematite; it forms alteration envelopes that extend for tens to hundreds of metres into the wall rocks around many of the mineralised veins. Siderite alteration is most diagnostic of mineralisation, forming alteration envelopes that extend for tens to hundreds of metres into the wall rocks around all mineralised veins. Fine-grained arsenopyrite and/or fine-grained pyrite commonly form alteration zones adjacent to high-grade ore shoots that extend for metres to tens of metres into the wall rocks. Widespread silicification is most easily recognised by the presence of numerous quartz veins.

Jan 1, 2002

By H Sichani-Teimouri, B N. Noller, J C. Ng, R N. Alsaadi, P L. Breuer, S Shini

Cyanide has been used for over a century worldwide for gold extraction. However, the presence of several metals and metalloids in ore requires greater amount of cyanide for an efficient gold recovery due to their solubilisation in conjunction with gold. The extraction residues are discharged into tailing storage facilities (TSFs) and may cause bird mortality if there is exposure to cyanide-bearing wastewater exceeding the toxic threshold. The toxicity arises from free cyanide released from weak acid dissociable (WAD) cyanide complexes. The International Cyanide Management Code (ICMC) has deemed 50 mg/L of WAD cyanide released into TSFs to be safe for wildlife protection. However, this concentration is based on observations of an apparent lack of toxicity rather than a toxicological approach. The National Industrial Chemicals Notification and Assessment Scheme (NICNAS) identified in 2010 that there is a lack of toxicity data to properly assess the environmental significance of cyanide levels at gold mines. Lack of knowledge for the toxicity of free cyanide and metal cyanide complexes to wildlife led to consider alternative direct assessment techniques for designating safe levels. Whilst toxicity may be assessed by using young chickens with animal ethics approval, the traditional bioassay approach to assess cyanide toxicity is impractical for gold mine TSFs. Bioassays using algal species such as Euglena gracilis, a unicellular alga, are widely used for ecotoxicological studies. A unique feature is that the Euglena gracilis Z cell has plant-like while SMZ cell has animal-like characteristics. The aims of this project are to evaluate the suitability of Euglena gracilis Z and SMZ strains to assess the toxicity of free cyanide and both strong (cobalt) and weak (zinc, copper and nickel) acid dissociable metal-cyanide complexes that may be present in TSFs.CITATION:Noller, B N, Ng, J C, Shini, S, Breuer, P L, Sichani-Teimouri, H and Alsaadi, R N, 2014. Development of a toxicity approach to evaluate free cyanide and metal cyanide complexes in waters associated with gold and other mining, in Proceedings Life-of-Mine 2014 , pp 573–590 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014