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Polyacrylamide flocculating agent has been used in the Leaching Division 'of the Risdon Works of the Electrolytic Zinc Company of Australasia Limited since October, 1960. The number of thickeners in the continuous thickening stage was thereby reduced from eight to three. There has been an increase of 25 per cent in throughput and a reduction of solids in thickener over-flow from 3-4 g/l. solids to 0·5 g Ir. solids. Reagent addition has been at the rate of 0·25 lb Separan NP10 per ton solids.Additionally there has been a gain of 3 per cent in current efficiency as the direct result of the addition of Separan NP10 to purified cadmium sulphate solution priOl; to electrolysis for cadmium metal. A smoother deposit has resulted and it has been possible to increase deposition time between strippings from 47 to 71 hr. However, there has been a slight increase in the lead content of the cadmium metal produced.The use of Separan NP10 to settle copper bearing residue in a batch process stage has resulted in a five-fold increase in settlement rate and a reduction in purification cycle time.INTRODUCTIONThe Electrolytic Zinc Company of Australasia Limited, Risdon, Tasmania, produces zinc by electrolysis of purified zinc sulphate solution, the raw material being zinc sulphide concentrate. In the Risdon process (Van Arsdale, 1953; J ohnstone, 1953; Ross, 1949) the compound zinc ferrite (ZnO.Fe203) is formed during the concentrate roasting stage. When the roasted material is leached in dilute sulphuric acid the zinc ferrite is not attacked, and it remains as part of the insoluble leach residue, of which it may form as much as two-thirds of the whole. The remainder is mainly unroasted zinc sulphide, unleached zinc oxide, lead sulphate, gypsum, silver compounds etc. The zinc in the residue may be 10 per cent of that in the original concentrate.Continuous thickeners are used to recover the valuable residue from the impure zinc sulphate solution and the...

Jan 1, 1963

Wet mining of auriferous gravels at L & MÆs Waikaka operation in Southland creates spoil dumps derived from stripping of a clay rich overburden, tailings from past dredging and the processing of auriferous sands and gravels. Over recent times, spoil dumps have slumped on six occasions, threatening the viability of the wet mining operation. Close examination of slump morphology, coupled with the sequence of material placement and rate of dumping suggested a mechanism associated with undrained failure of a 2 m layer of silt and sand tails forming the base of dumps.Commencing with some information on the geotechnical properties of source overburden, back analysis of failure morphology and sequence and development of undrained loading conditions from first principals, the most likely failure mechanism and factors controlling failure were defined. Based on analysis results, a scheme to stabilise the lowwall dumps was developed and implemented, augmented by continuous monitoring of pore pressures in the basal wet tails, and laboratory testing for confirmation of computed material properties.Lowwall spoil stability has improved since implementation involving changes to the method of spoil loading, and modification of wet tails composition to improve permeability and drainage of the basal wet tails under load. The method and approach to prediction and verification of failure mechanism provide a sound basis for continued mining of deeper auriferous gravels.

Jan 1, 2002

By E Villaescusa, C Drover

Fully resin encapsulated threaded bar and cement grouted cable bolts are common forms of reinforcement for underground mining excavations constructed at great depth. These elements are frequently installed to dissipate the dynamic loads caused by violent rock mass failure mechanisms. Failure of the ground support scheme without rupture of the reinforcement elements implies that the maximum energy dissipation capacity of the scheme was not utilised. The ground support damage mechanisms are useful to identify in this context as they reveal vulnerabilities which limit the scheme performance. This paper presents a number of field observations of reinforcement performance following a range of dynamic loading conditions. It was observed that fully resin encapsulated threaded bars exhibit variable behaviour. In particular, inconsistent resin encapsulation was frequently observed in combination with surface support failure, indicating that the retention function of these elements may allow preferential loading of the surface support system. Observations of cement grouted, twin-strand plain cable bolts reveal a common mode of damage involving differential displacement across the steel-grout interface and slip of the cable within the borehole. This is common where strands are not mutually tensioned with barrel and wedge assemblies. Surface fixtures that exceed the strength capacity of the cable strand are required in order to minimise the occurrence of this response. Improved load transfer from the rock mass and surface support to the cable can thus be achieved, particularly where small block size failure occurs.CITATION:Drover, C and Villaescusa, E, 2016. Field performance of fully encapsulated reinforcement during violent failure events, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 659–668 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By N Dube, K L. Sandvik, C Mutevhe

Trojan Nickel Mine is the largest producer of Ni, Cu and Co in Zimbabwe. The mine has operated a nickel flotation concentrator and base metal refinery continuously since 1969, creating 28 million tonnes of sulfide bearing tailings, five million tonnes of permanent waste rock and about seven million tonnes of smelter slag. Exposure of the sulfide bearing minerals renders them susceptible to oxidation in the presence of water and oxygen, resulting in acidic solutions with elevated concentrations of total dissolved solids, sulfate, metals and residual flotation chemicals in various waters draining from the mine site. These pollutants pose a direct threat to the environment and human health, and understanding their deportment and behaviour in the various waste streams is essential in the mineÆs environmental objectives to prevent or minimise adverse impacts arising from its operations. A geochemical assessment of the pollutants was carried out to compute a mass balance between the major sources of pollution and the distribution and fate of pollutants in waste streams from the mine site. Waste rock, tailings, surface water, ground water and sediments were sampled, tested and analysed. Mineral composition and water chemistry data show that geochemical reactions are responsible for the release of pollutants from waste rock, tailings and plant spills. Drainage from the mine area is near neutral due to buffering by magnesium carbonates in the fine fraction of the tailings. The natural wetlands that exist downstream of the waste rock and tailings dams are effective in reducing metal loadings to water courses. However, solutes and heavy metals are occasionally released to surface and ground water, when their concentrations peak during the dry season. The results demonstrate the necessity to understand the natural chemical processes that characterise the distribution of pollutants in nature and how such knowledge can be used to develop cost effective methods to remediate pollution in the natural environment.

Jan 1, 2006

Effects of High Pressure Grinding Rolls on Platinum-Bearing Ores and the Flotation Response as Compared to the Conventional Ball Mill Three major PGM ore types from the Bushveld Complex of South Africa: Merensky, UG2 and Platreef were comminuted with the use of the high pressure grinding rolls (HPGR). The influence of the feed characteristics and the various operational and design features of the HPGR on energy consumption, throughput, mineral liberation and PGM flotation recovery were investigated. The test work variables included two feed top sizes of 12 mm and 6 mm, specific grinding forces ranging between 3 - 7.5N/ mm2 and zero gaps of 1.5 mm and 3 mm. The results show that the influence of the HPGR operational and design features on energy consumption, throughput, mineral liberation and PGM recovery are ore dependent. The size reduction-specific energy relationships show that the most energy efficient utilisation of the HPGR for Platreef ore was at the lower specific grinding force of 3N/mm2 and the zero gap at 3 mm. For Merensky and UG2 ore on the other hand, the most energy efficient operation was at the higher specific grinding force of 7.5N/mm2 and the zero gap of 1.5 mm. At a specific energy input of 3 kWh/t, reduction ratios (F50/P50) of 6.5, 3.8 and 10 were obtained for Merensky, UG2 and Platreef, respectively for feed top sizes of 12mm. Further application of the HPGR as a pregrinding stage to a ball mill showed a 25 - 30 per cent increase in throughput for Merensky and UG2 ore. Batch flotation tests performed on selected samples appear to indicate that ore comminuted with the ball mill had superior grades compared with that ground with the HPGR. However, Merensky and UG2 ore comminuted at different HPGR operating conditions showed distinctions in PGM recovery. Platreef on the other hand did not appear to show any differences. Therefore, this study highlights the significance of ore type and operating variables in HPGR applications with regards to energy efficiency, throughput and PGM recovery.

Sep 13, 2010

The Central Andes in Peru, Chile, Bolivia, and Argentina , contain two contiguous terranes which were accreted to Gondwanaland between the end of the Devonian and the end of the Triassic. These terranes, Arequipa in the north, and Chilenia in the south, differ from each other in the timing and style of their metallogenic development. However, they contain over 90% of the Central Andean porphyry copper resource. The copper porphyries in the Arequipa terrane are Paleocene to lower Oligocene in age, whereas the Chilenia deposits are mid-upper Cretaceous and mid-upper Miocene. Porphyry copper deposits occur outside these terranes, but are all Miocene in age. Miocene porphyry-style mineralisation also exists in the Arequipa terrane, but is copper-deficient and gold-rich. The accreted terranes may have favoured porphyry and other styles of copper mineralisation because they possessed relatively thin continental crust compared to adjacent parts of the Andes. Crustal thickening which commenced at about 30 Ma in the Arequipa terrane coincided with a major change to polymetallic, precious metal mineralisation which commonly displays high sulfidation characteristics.

Jan 1, 1995

IN this paper it is proposed to present certain features of operating practice at the Port Pirie works of The Broken Hill Associated Smelters Proprietary Limited, in the smelting in a blast furnace of lead ores carrying a high concentration of zinc.The subject matter selected for presentation is:(i) The effect of zinc on lead blast-furnace operations, together with an outline of the methods adopted in actual practice in dealing with the zinc problem.(2) Development of the height of tuyere above the bottom of the jacket, and the extension of the tapping interval and the combined effect of both factors upon the lead content of blast furnace slag.It will later be seen that one phase of the investigation carried out in connection with the effect of zinc on blast-furnace operations was largely responsible for the decision to increase to a marked degree the height of the tuyere above the bottom of the jacket.Due to this interdependence, it has been considered advisable to deal with the two features above mentioned.The high concentration of zinc in the lead-bearing materials smelted at Port Pirie has brought with it those troubles which are associated with zinc in the smelting operation.In the early stages of the history of The Broken Hill Associated Smelters Pty. Ltd. the trend towards increasing cost for labour, fuel, and stores, etc., rendered it necessary to increase the lead content of the charge, and reduce to a minimum the quantity of barren flux used.

Jan 1, 1931

Experimental Validation of a Flotation Cell Model

Sep 13, 2010

The Mineralogy and Reactivity of Pyrrhotite from Selected Nickel Ore Deposits and its Effect on Flotation Performance

Sep 13, 2010

By D M. Hunter, S M. Iveson, K P. Galvin

For low density materials such as coal, density-based fractionation of particles via the sink-float method is relatively simple due to the availability of liquids of suitable density; however, for high density minerals, suitable heavy liquids are less available and those that are available are expensive and pose significant hazards. At best, sink-float separation can be performed up to densities of 4400 kg/m3 with the use of Clerici’s solution at elevated temperatures. Hence the direct measurement of grade-recovery and density-partition curves is problematic. Therefore, in most cases, beneficiation plants must rely on methods such as QEMSCAN, density tracer particles or very limited information to guide them in the design and optimisation of their plants.This paper describes a density-fractionation method utilising laminar flow through a system of parallel inclined channels to generate a series of overflow fractions at different flow velocities. Here the particles are subject to precise hydrodynamic forces with minimal dispersion or mixing. The size distribution of each overflow fraction at a given flow velocity is obtained using a laser particle size analyser, and combined with a laminar flow model to deduce the corresponding density distribution. The paper describes the application of the method to measure the separation achieved using a REFLUX Classifier to obtain the corresponding feed, product and reject ‘washability curves’, and in turn the full partition surface. Approaches used to corroborate the findings are discussed.CITATION:Hunter, D M, Iveson, S M and Galvin, K P, 2017. A batch elutriation technique for the density-based fractionation of iron ore, in Proceedings Iron Ore 2017, pp 195–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By W P. Player

The legislative operating environment, or the mineral regime, that a country has to offer is one of the key determinants that a company wanting to invest in an area takes into account in formulating its investment decision.   The New Zealand Government recognises this and the importance of getting the regime right in order to provide for continuing investment in mineral exploration and mining in New Zealand . In recent years, the Government has given considerable attention to developing legislation which provides for investment to take place; for those making the investments to have a stable, fair and open investment environment with government intervention only when considered absolutely necessary because other approaches are not working; and for the people of New Zealand to know that investment must meet acceptable health and safety standards and have acceptable impact on the environment. Also of key importance is having a clearly defined mining regime which includes rules on how to obtain a permit and rules in respect of ongoing permit compliance, rights to develop a mineral resource and permit conditions (in particular, the royalty regime). In New Zealand , these matters will all be addressed in what are referred to as 'minerals programmes'.   The Crown Minerals Act 1991, which is the legislation governing the allocation and management of permits for Crown owned minerals, requires that the Minister of Energy prepare minerals programmes. Minerals programmes establish the policies, procedures and provisions that the Minister shall follow in exercising his or her functions and powers under the Crown Minerals Act. Minerals programmes set out the principal reasons for and against adopting these policies, procedures and provisions and also restrictions on prospecting, exploration and mining for Crown owned minerals. Essentially minerals programmes define the mining regime for the minerals to which they apply, other than the taxation regime, environmental and health, safety provisions, land access matters and general matters concerning the investment climate.

Jan 1, 1995

The Round Hill gold-scheelite deposit is located three kilometres from Macraes Flat and approximately 60 kilometres due north of Dunedin, New Zealand. A mining feasibility study is currently being undertaken on the deposit by BHP Minerals (New Zealand) Limited, who are the managers and operators of a Joint Venture with Home Reef Mining Limited. BHP has a 70 per cent equity in the project area.

Jan 1, 1987

By R Simcock

Why Rehabilitate? Legislative Requirement Land rehabilitation is a condition of resource consents for mining. Clause 17 (1) of the Resource Management Act 1991 (duty to avoid, remedy, or mitigate adverse effects) provides the legislative basis for local authorities to impose resource consent conditions requiring land to be rehabilitated to approved uses during and after mining.

Jan 1, 1997

By Ross R

Although mining is an old industry its management is quite a new science, and its complications are now being recognised as demanding expert knowledge in many branches of technical and professional education. Not the least amongst these isaccountancy, for probably its most important problem is "How to control the expenditure." Unlike most businesses a mining company stands almost entirely in the light of a purchaser in the world's markets, and not as a seller, except say for product so the established and perfected systems of modern industries cannot be adopted for mining purposes. For this reason it has been left for late years to consider the matter seriously, and now a number of well-managed concerns have devised costs systems to suit their own requirements.Very little, however, has been published and even that is disjoined and difficult to make use of. Some of the costs systems in vogue, although elaborate and imposing, are not of very great value for keeping check on wasteful expenditure, or for displaying the commercial effect brought about 'by any particular change in practice, or by an addition or alteration to a portion of existing plant.

Jan 1, 1912

By K Pery, J Leahy

Established metallurgical plants operate in a complex environment of interdependent drivers including technology change, operating and maintenance practice, evolving markets, HSEC requirements, statutory and plant requirements, personnel turnover, ore supply, and financial conditions, to name a few. A successful optimisation program should comprehend these factors and drive towards not only lower operating costs, but also higher rates of return for a given level of investment. Optimisation programs have the potential for very high rates of return on capital that Greenfield projects rarely have. This paper presents a robust strategy and methodology for plant optimisation initiatives as well as a case study of how it was implemented at the QNI Yabulu refinery in Queensland, Australia by an integrated team of researchers, engineers and operators. The methodology is premised on the fact that nobody knows the production asset as well as the current operating team. It covers the optimisation process from ideas generation, various stages of selection against the agreed criteria, development, including testwork, funding approval and implementation. It highlights the benefits in the use of integrated teams, the establishment of a sound project basis, and a diligent, phased approach.

Jan 1, 2004

The Significance of Internal Recycle in Froth Flotation

Sep 13, 2010

By T F. Guerin

Explorationn and mining have shown to cause significant impacts to the terrestrial and marine environment. Current mining and exploration techniques are outlined in the light of their potential to impact upon the environment, ie negligibly, negatively or positively. A profile of five Australian-based gold producers is presented. The development of protocols to specifically deal with the highly regulated and ever changing, mining and environmental legislation. demonstrates mining companies can successfully opcrationalise the concept of sustainable development.

Jan 1, 1992

There are circumstances where the ordinary techniques of experimental variography in geostatistics û now in common use despite their recent origin û are not quite successful. This paper describes a new addition to the geostatisticians tool kit developed by one of the renowned leaders in the field to cope specifically with these circumstances. Possible application of this technique will be outlined when it will be seen that there are still problems remaining to be solved in its use for economic evaluation of deposits with irregular mineralisation.

Jan 1, 1984

This paper contains an account of some creep tests on electrolytic lead and some of its alloys. The stresses used in determining creep were 500, 350, and 200 lb. per sq.' in. The alloys contained silver, bismuth, tellurium, antimony and zinc respectively. All were castin vacuo, and tested "as rolled." Tests were done also on electrolytic lead which had been cast in air.The electrolytic lead contained 0.0005% total impurities.The preparation and vacuum casting of this lead have been described in a previous paper in this series. The preparation of the alloys, and the air casting of the electrolytic lead, are described in the next section.EXPERIMENTAL PROCEDURE.Every effort was made to keep the vacuum-cast specimens from contact with the atmosphere throughout their history.The ingots were stored eIther in a vacuum desiccator or immersed in heavy oil. The creep specimens were coated with vaseline except during rolling, etching and photography, which involved exposure to the atmosphere for about 45 minutes all told.It is not claimed that vaseline is a perfect shield against the intrusion of atmospheric gases. Possibly during the months that some tests were in progress the gases diffused through the vaseline and gained a limited access to the lead.Nevertheless, the use of vaseline gave protection that brought the tests nearer the ideal at which the author aimed, *Research Fellow, Dept. of Metallurgy, University of Melbourne.

Jan 1, 1936

Experiment of Improving the Quality and Decreasing the Impurity of Titanium Concentrate in Panzhihua Mine in China

Sep 13, 2010