Search Documents

Attempt has been made to determine the nature of charge on activated carbon surface by studying the electro-kinetic properties of the carbon in the presence of cations, anions and aurocyanide solutions. The zeta-potential measurements were made in the presence of individual ions and also in combinations. The cations and anions chosen were those commonly associated with gold bearing ores in Kalgoorlie area. It was found that the iso-electric point of Norit Carbon was at pH 4.45; below this pH the charge was positive, while above, it was negative. In the absence of gold cyanide solutions and in the presence of individual cations the i.e.p. shifted to the alkaline range (pH 7.2-8.5) while in the presence of anions the i.e.p. was shifted to less than pH 3.5. In the presence of aurocyanide solutions, the iso-electric point was still in the acid region irrespective of whether anions or cations were present. The probable mechanism for such a behaviour has been attempted after measuring the specific conductivities of solutions before and after gold adsorption, by studies using the electron- probe-mirco-analyser, and S.E.M. on the carbon surface.

Jan 1, 1982

By D Anderson, W Timms

"A geotechnical centrifuge can characterise and model the interaction of tailings and fluids over very long time periods by accelerating drainage and consolidation processes. This technology can be considered an environmental ‘time machine’ for designing and evaluating tailings storage projects and verifying numerical models. The Broadbent G-18 geotechnical centrifuge (2 m diameter, up to 875 rev/min) and associated equipment is a unique facility commissioned in 2011 at UNSW Australia for applied research in low-permeability materials such as mine tailings. Two centrifuge modules are available: the permeameter module for characterisation and physical modelling and the strongbox module for physical modelling.This paper presents examples of geotechnical centrifuge applications for the: consolidation of slurries and dewatering design of earthen barriers compatible with tailings chemistry prediction of contaminant mobility. The specifications and capability of the UNSW Australia geotechnical centrifuge and associated instrumentation is also presented, along with preliminary analysis of the confidence intervals associated with permeability testing of a set of samples of varying heterogeneity. Drainage velocity through a mine tailings sample increases linearly with g-level in the centrifuge permeameter until tailings consolidation occurs. Alternatively, geotechnical centrifuge experiments can be designed to limit consolidation so as to quantify permeability changes that may occur with geochemical interactions between fluids and mine tailings or earthen containments. Reactive solute transport through mine tailings can be simulated at realistic solid:liquid ratios when chemical equilibrium is maintained during geotechnical centrifuge testing. Carefully designed physical models of tailings disposal tested at accelerated gravity can therefore provide a realistic evaluation of tailings consolidation and drainage and the potential for subsurface migration of contaminants from mine tailings over long time periods.CITATION:Timms, W and Anderson, D, 2015. Geotechnical centrifuge technology for characterising the interaction of tailings and pore water over decadal time periods, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 247–252 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 27, 2015

By T Laurencont, C Unger

The Mount Morgan minesite, located approximately 40 km SW of Rockhampton in Central Queensland, comprises 270 ha of unrehabilitated land which is the currently the major source of acid mine drainage run-off and seepage to the adjacent Dee River. Additionally, the minesite hosts an Open Cut Pit which contains 9000 ML of acidic and metal-rich water. In the absence of active management of water in the pit, there is a 50 per cent probability of an uncontrolled spill occurring in future years. The development of a contingency plan for management of overflow from the pit in the short term, has incorporated findings from numerous studies relevant to the Open Cut Pit including, but not limited to, water balance, contaminant source identification, toxicity testing, water quality profiling and limnological modelling, and estimates of probability of overflow. Extensive stakeholder consultation and peer review were also undertaken during the formulation of the contingency plan. The medium-term goal of lowering the water level in the pit to reduce the current high probability (50 per cent) of uncontrolled overflow to acceptable levels of risk is proposed to be achieved by a campaign of chemical water treatment. The treated water will be discharged to the Dee River, and sludge returned to the pit. The methodologies used for the selection and development of the water treatment process, that is proposed to involve treatment with lime, are described. Water treatment is the short- to medium-term component of a long range rehabilitation plan for achieving a negative pit water balance, and sustainable management of acidic water across the whole site. Achieving this ultimate goal will involve: reducing the inputs of water to the Open Cut Pit such that the annual water balance is zero or net negative, thus removing the need for water treatment in perpetuity; maximising, by surface rehabilitation works, the quality of run-off reporting to the Dee River; and minimising the volume of acidic seepage reporting to the seepage interception system. Possible strategies for achieving this long range goal consistent with overall site rehabilitation objectives are currently being developed and costed.

Jan 1, 2003

The application of reinforcement techniques to enhance the stability of underground coal mine roadways subject to high stresses is discussed. Research conducted in the Illawarra Coal Measures has been aimed to delineate the factors which influence the behaviour of rock above roadways and the performance of the reinforcement placed. Design considerations for the reinforcement of mine roadways in the Bulli coal are based on a quantification of the rock response together with a reinforcement strategy to enhance the structural integrity of the roof strata.

Jan 1, 1986

By Bockhorst R. W, Christopher D. A

Over the past fifteen years, horizontal drilling in coal seams for advance degasification has become an established practice in the United States of America. Consolidation Coal Company pioneered the development of the horizontal drilling system and licensed the technology in the U.S. A. and to Du Pont (Australia) for commercial production. This paper discusses the most recent developments in the equipment design, especially the borehole telemetry system, known as the Downhole Drill Monitor (DDM).

Jan 1, 1988

By T Laurencont

The Queensland Department of Natural Resources and Mines (NR&M) accepted the environmental liability for the Mount Morgan minesite in 1991. This gold and copper mine located 38 km southwest of Rockhampton had been in operation for more than 100 years. Mining leases are still active while the feasibility of a reprocessing operation is carried out. From 1993, NR&M have operated a seepage interception pumpback system which has reduced the chronic load of acid rock drainage (ARD) to the adjacent Dee River, a tributary of the Fitzroy River system. In early-2000, it was recognised that a ten-year plan for rehabilitation of the mine, along with significant funding would be required if a long-term sustainable rehabilitation strategy was to be implemented at this minesite, ultimately making the seepage interception system redundant. A rehabilitation planning workshop coordinated by NR&M was held in May 2000. This workshop brought to the mine a range of technical expertise and key stakeholder groups. This workshop provided a technical forum for review of studies undertaken and to identify priority projects, which needed to be undertaken in the future to more clearly define contaminant sources on the mine site and to prioritise the rehabilitation program. Stakeholder consultation enabled the project team to be clear on community and other government (eg Environmental Protection Agency) expectations. It is clear that the future of the economically depressed community of Mount Morgan will be reliant on the careful management of the significant heritage values at the minesite for tourism, education and research. In the first year (2000), priority studies were initiated, which included whole of site studies on water balance, contaminant sources and a review of occupational health and safety and environment of the minesite and conservation and heritage scoping. Baseline vegetation and soil materials surveys were also initiated. The outcomes of these studies helped to shape the work program for the following year, while providing a basis for an additional funding application, which was granted. The second year of studies focused on building upon the existing baseline studies completed. In addition, studies focussed on addressing the priority issue of contingency planning for overflow from the open cut pit in accordance with best practice management of release water and river monitoring strategies were completed. Completion of these projects over the next six months will enable the optimal rehabilitation strategy to be defined in 2003. This optimal strategy may require the use of a water treatment plant for part of the ten-year program to provide space in the open cut pit for the deposition of ARD contaminant sources (eg waste dumps, tailings). It is envisaged that some sources will be rehabilitated insitu while others will be relocated to the open cut pit. Implementation of this strategy will be dependent on subsequent funding.

Jan 1, 2003

By Hinrichsen H. D, Rathburn D. R, Stieger W

The present situation in the field of iron ore pelletizing is briefly described with particular view of the Lurgi/Dravo travelling grate process. To meet todays pellet quality requirements with regard to physical and metal- lurgical properties it is often necessary to add basic fluxing materials. It has been de- monstrated that for certain ores, basic addi- tives provide a considerable improvement in fired pellet quality. The production of self- fluxing pellets is becoming increasingly attractive. One Lurgi/Dravo plant is now in operation and another is under construction which were designed for the production of self- fluxing pellets. Self-fluxing pellets may be considered as the primary or exclusive blast furnace burden and the installation of a sinter plant is not necessary if the pellet plant-can handle all in-plant fines. Reference is made to the first pellet plant utilizing iron ore concentrate, in-plant fines and basic flux. The use of solid fuel for pellet indura- tion is discussed because of the increasing prices and possible shortages of heavy oil and natural gas. Since there is a strong tendency to increasing plant capacities, the design fea- tures of travelling grate pelletizing plants for productions up to 6 million tonnes are Discussed.

Jan 1, 1974

By Mathew P. J

The CSIRO Division of Mineral and Process Engineering in Melbourne has been developing on-stream analysis sensors based on neutron and gamma radiation for better control of quality and process operations. This has resulted in the development of Ironscan, an on-stream analyser that measures the iron content of both lump and fine iron ore on conveyor belts. It can be mounted under existing conveyors with minimal modifications to the conveyor structure and can cope with steel cables in the belt. An interface gauge and an on-stream coal ash analyser have also been developed, both based on measurement of natural radioactivity. The interface gauge monitors the interface between liquor and mud in thickeners and washers, provided the natural radioactivity of the mud is sufficiently high to detect it above background. The natural-gamma ash gauge is a valuable addition to the Coalscan range of ash gauges. It is applicable to heavily laden coal conveyors or bins where the coal bed thickness exceeds 30 cm, and also to lightly laden conveyors, provided the coal is profiled on the conveyor.

Jan 1, 1991

By A G. Grice

Surface disposal of mining processing wastes is usually perceived as an undesirable consequence of meeting societyÆs needs for metals and minerals. Environmental disasters associated with the discharge or storage of such wastes, though infrequent, can have very damaging consequences for the environment and the industry. Reducing or eliminating the potential for such events may be achieved by placing some or all of these processing wastes back into the voids created by the mining operations. Processing operations may limit or enhance the opportunities for using tailings and other waste products as a backfill material. Backfilling is a truly multi-disciplinary process and requires the informed involvement of mining, metallurgical, engineering and environmental specialists. This paper describes the range of fill types currently being used in Australian mines, particularly those utilising processing wastes as constituents. It focuses on how processing operations can affect the suitability of these materials for the various types of fill, the resulting fill properties, fill performance and costs.

Jan 1, 2002

By Fuller P. G, Miller D. R

Hydraulic fill using surface sand deposits or cycloned tailings has been used in underground mining for at least fifty years. Current technology requires a permeable fill and high cement additions for strong fill. Shortages in quantities of acceptable fill with finely ground ore may require rockfill or aggregate to be introduced as a supplement and these usually incur additional distribution costs. Alternative approaches to the problem are now being developed whereby the pulp density of the fill is raised so that it is delivered either as a dense slurry or as a paste. These regimes of fill behaviour are defined together with the plant and pumping techniques required to prepare and deliver the materials. Test techniques to define the different regimes of behaviour are identified and the variation in material properties for fills with varying pulp densities are outlined. The results indicate that high pulp density fills are stronger and have less permeability restrictions than conventional fills and that aggregate can be carried with the pulp. Thus the disadvantage of finer materials can be turned into an economic advantage. Criteria are developed for defining the type of operation suited to this Technology.

Jan 1, 1986

By G Bournival, Y Saavedra Moreno, S Ata

Flotation frothers are heteropolar molecules that are preferentially adsorbed at the bubble interface to enhance the flotation performance by promoting the formation of small and stable bubbles. Frothers have different characteristics that can be used to classify them. A classification framework has been recently presented by Saavedra Moreno et al (2022) to classify non-ionic frothers by conducting a principal component analysis (PCA) and a hierarchical clustering analysis (HCA). However, for the purpose of the present research, only five frother characteristics, including molecular weight (MW), hydrophile–lipophile balance (HLB), critical coalescence concentration (CCC), the minimum Sauter mean diameter (DL), and foam stability index (DFI) were used in the PCA and HCA. All those characteristics were evaluated for a two-phase system in the absence of particles. Realising the important role that particles play in froth stability and behaviour, the effect of hydrophobic particles on the presented frother classification framework was investigated in this study. Four frothers with different characteristics, methyl isobutyl carbinol (MIBC), 1-pentanol, tri (propylene glycol) (TPG), and tri (propylene glycol) methyl ether (TPM), were chosen. The experiments were carried out in the presence and absence of silica particles esterified with 1-pentanol. It was evident that the results for 1-pentanol, TPM, MIBC, and TPG in the three-phase system agreed well with the frother classification presented for the two-phase system as frothers were clustered in the same groups. The findings from this research support the use of the frother classification system presented in two-phase system to select a specific frother for a particular application without the necessity of conducting laborious experiments in a three-phase system.

Aug 24, 2022

By G Baird, M Seto

A low-cost methodology that allows the determination of in situ stresses using oriented core specimens has been investigated. The technique can be used to determine the stresses during the early stages of a project, even in undeveloped areas of a mine. The research aim was to compare the experimental results estimated by the Acoustic Emission and Deformation Rate Analysis methods with those estimated by conventional Hollow Inclusion cell measurements. The studies have been focused on full stress tensor determination from a single oriented rock core. In all cases the rock core specimens recollected the in situ stresses reasonably well compared with the standard overcoring method.

Jan 1, 2000

By Jena, Anand S, Das R. P

Leaching studies were carried out on Indian Ocean manganese nodules using sulphuric acid as the lixiviant. By leaching the nodules with 8 per cent sulphuric acid for 12h at 100°C, copper and nickel could be completely extracted along with 50 per cent cobalt and 6.2 per cent manganese.94.2 per cent of the iron was also dissolved. To increase manganese and cobalt extraction, charcoal was used as a reductant. The role of charcoal was to reduce the manganese dioxide and render it soluble as manganese sulphate as well as to facilitate solution of the cobalt minerals associated with the manganese dioxide. Various leaching parameters were studied including acid concentration, amount of reductant, leach time, pulp density and leach temperature. It was found that by leaching the nodules with 10 per cent sulphuric acid at 100°C for 4h using 5 wt/wt per cent charcoal (0.05g of charcoal per g of nodule) almost complete extraction of copper, nickel, cobalt and manganese could be achieved. However, under these conditions all the iron present in the nodules was also leached.

Jan 1, 1989

By Newell R

The situation in which a gas stream flows through a bed of solids is found in many extractive metallurgy operations. Examples include blast furnace smelting, sintering and pellet firing. In such cases the resistance of the bed to fluid flow and heat transfer is of major significance to the operation of the process. This depends on the structure of the bed, which in turn is influenced by the manner in which the materials are charged to the bed. In this work, packed beds of hematite pellets of two different sizes were prepared in which the pellets were charged as a uniform mixture and in layers. The porosity, flow resistance and heat front velocity were measured and compared for the different bed configurations. For layered beds, the overall porosity and heat front velocity increased while the flow resistance decreased when compared with the values obtained for the uniform mixture. The size of the layers also had an effect on flow Properties.

Jan 1, 1991

Woodlawn Mines began underground operations in 1986. At the time of going underground it was envisaged that there would be no 'contract' payment to the underground employees. This was a relatively unique step to make, especially as most major underground mines in Australia relied heavily on the contract system to motivate their workforce. (Obviously with varying degrees of success.) Woodlawn faced the task of motivating their employees through a multi-skilled system with a great emphasis on leadership and a genuine care for their employees. The 'proof of the pudding' is that Woodlawn has not lost any time over industrial issues since beginning underground operations in 1986. To achieve success in any operation the organisation must not only be advanced in its management principles but also be prepared to be innovative in the way it deals with physical problems, ie ground control, equipment selection and maintenance. Difficult ground conditions at Woodlawn have necessitated the deployment of two Cabolt Jumbos and the construction of cost-effective shotcrete systems. The shotcrete system now being built has been tested in a prototype form and is proving to be a safe and simple way to manage weak, low stress friable ground. Although the ground at Woodlawn has low stress component by virtue of the fact the ore can have a density of 4.5dm3, cable dowelling has become a necessity. The two cable dowel jumbos install high quality reinforced cables. The pressure of 'production' means that these machines must be consistently available for use and the training of maintenance personnel and operators ensures that a maximum of cable dowels can be installed over any given time span. In any modem mine ventilation is a primary concern and the major area of concern comes from the vehicles themselves. In our recent replacement for the standard 'Toro' loader, three engine options were considered. A relative newcomer to underground mining was accepted. The Detroit 60 series (DDEC) engine came with a great reputation and has lived up to this. The engine has an electronic management system that reduces particulates to a hardly visible minimum, provides great amounts of engine power and reduces fuel consumption by approximately 45 per cent. The operational benefits of such an engine are worth sharing through this conference.

Jan 1, 1995

By Floyd JM, Bultitude-Paul J

The development of a process for the extraction of antimony from materials produced by Greenbushes Tin Limited has been carried out based on theoretical and laboratory studies. The materials treated have included concentrates of tantalite and cassiterite containing antimony at levels ranging from 0.3% to 2%. Roasting under controlled atmospheres is required to stabilise Sb203 rather than the low vapour pressure metal or higher oxide. Sulphidising additives such as pyrite, pyrrhotite or sulphur give enhanced antimony removal from tantalite and cassiterite at roasting temperatures of 900¦ to 1100¦C. Substantial elimination of antimony to levels of 0.1% or less was Achieved.

Jan 1, 1986

By Hyslop W

It is shown that coke has a major influence on the pattern of operation and on the aerodynamics of the blast furnace and that the physical and chemical characteristics of coke, at each stage in the furnace, determine its ability to satisfy requirements for iron production and coke economy. Analysis of coke sampled from operating furnaces is compared with furnace behaviour. The available data suggests the importance of segregation, strength, size change and chemical degradation of coke on furnace performance. Correlations are presented for coke breakdown ratio as a function of coke rate and hearth diameter which shows that breakdown increases with hearth diameter and with decreasing coke rate. It is also shown that the Micum tests do not reflect the coke strength in a predictable way and that solution reactions appear to play an important role in giving rise to a pitting effect on the cell walls of the coke with the resultant deterioration in coke properties. The catalytic effect of activating substances, such as alkalis, is noted and results are presented which show the effect of carbon solution on the coke strength. The importance of coke in the stack and in the bosh is discussed and flooding results are presented for BSC furnaces which show the probable driving limits for the furnaces considered. It is also shown that coke sampled from different tuyeres in a furnace gives quite different flooding limits. Other applications of the coke test work at BSC are also noted and the relevant objectives listed.

Jan 1, 1975

By J P. Sykes, T C. McCuaig, J E. Vann

Resources added to the global metal inventory through exploration over the past 15 years have been generally of poor quality (declining grades, recoveries and lack of acceptable financial return). Similarly, companies opting for an acquisitions-based strategy have had to pick from a group of poorer quality resources left from previous exploration booms, and will struggle to deliver this metal to market economically. Increasing difficulty in obtaining sufficient social and community acceptance of mining projects and potentially an energy-constrained future may exacerbate this problem, redefining what is considered ‘ore’. There will need to be more focus on deposit quality, defined as sustainable margin in the future business environment.Traditionally there has been a lack of translation of ‘mineralisation quality’ back to mineral project design and mineral exploration. This disconnect is due to two main factors: the first is technical – inherent deposit variability; and the second is organisational and socio-psychological –the mindset of explorers and project managers themselves.There are four elements to value realisation for a mineral deposit: (1) social licence to operate; (2) geological factors (depth, geometry, water and geotechnical, and geometallurgy – influenced by texture, mineralogy, chemistry and grades); (3) financial engineering (capex, opex, future commodity prices, future energy prices), and (4) operating factors (production rate, recovery, energy consumption). These elements are strongly interdependent, and geology underpins and drives linkages between them. A quality deposit addresses all of these elements and thus can be developed in a time frame that allows acceptable returns to the owners of the invested capital.Geological drivers of the above elements can be measured and mapped throughout a deposit. Moreover, when viewed in the context of mineral systems, a predictive understanding of the common causative processes of quality (despite deposit-scale variability) is emerging, and with it the ability to target quality of mineralisation, not just quantity of mineralisation.The second factor is a ‘heuristic software problem’. Current lines of education (and consequently organisational and professional structures) are discipline-based, producing ‘silos’ that do not speak each other’s language and work with different ‘mental models’. People who effectively recognise systemic links between these silos are called ‘boundary spanners’, of which we propose two distinct types: outside-insiders and inside-outsiders. Outside-insiders are people who are within a community, but recognise advances in outside fields and effectively integrate them into the community. Inside-outsiders start outside of a community, and successfully bring new ideas into it. Common traits in boundary spanners are: they seek exposure to (and embrace) key ideas that are outside of the framework of their own specialisation; they have high mental processing ability (MPA) – the ability to connect systems that are currently not perceived to be connected; and they introduce ideas from outside a field into a new context in a way that re-frames the field.The challenge is to identify and nurture potential boundary spanners that can build critical links, in particular between the (largely geoscientific) mineral exploration mindset and the (largely non-geoscientific) project development mindset. Critical linkages to be built are between mineral system science, targeting science, and whole of value chain modelling.CITATION:McCuaig, T C, Vann, J E and Sykes, J P, 2014. Mines versus mineralisation – deposit quality, mineral exploration strategy and the role of ‘boundary spanners’, in Proceedings Ninth International Mining Geology Conference 2014 , pp 33–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

The results of about 30 years of exploration and mining activities and research studies in the Kambalda mining district, Western Australia, have led to general agreement that the komatiite-associated Ni sulphide ores formed as a result of igneous processes (Ross, 1974; Ross and Hopkins, 1975; Gresham and Loftus-Hills, 1981; Cowden, 1988; Lesher, 1989 and many others). Despite this agreement, the controls on sulphide supersaturation and concentration of the resulting sulphide in a limited zone, remain uncertain and controversial. A major uncertainty is the source of sulphur in the ore deposits. Two principal sulphur sources have been proposed: 1. komatiite lava/magma (Hudson, 1972; Naldrett, 1973; Lesher et al, 1981; Cowden, 1988; Foster et at, 1995), and 2. sedimentary material (Groves, Barrett and McQueen, 1979; Lesher, Arndt and Groves, 1984; Lesher, 1989; Lesher and Campbell, 1993). Resolution of the uncertainty regarding the sulphur source is required for a complete understanding of the controls on ore formation, which in turn would significantly impact exploration strategies in the Kambalda mining district and elsewhere. This paper reviews the constraints on sulphur sources for the komatiite-associated Ni sulphide ores in the Kambalda mining district. The focus is on the general characteristics of the ores and surrounding rocks: individual ore deposits are not described, though specific examples are noted where appropriate. The stratigraphic and volcanic settings and geochemical (major and trace element and isotopic compositions) characteristics of the ore deposits and surrounding rocks are considered within the context of the competing sulphur source models, and future directions of research in the district are noted.

Jan 1, 1996

By Lee H. G, El-Rahaiby S. K

The literature relating to reduction of sulphides by carbon using lime as sulphur-absorbent is reviewed. A stage-wise thermodynamic model is employed to evaluate the practical feasibility of the direct reduction smelting of galena (PbS) concentrates with a carbon reductant in the presence of lime; a coke-rate of 65 kg/ton Pb is predicted by the model. The experimental data on the reduction of PbS:4CaO:4C mixtures under nitrogen were correlated by means of a finite difference numerical method and the values of the intrinsic rate constant I1 were derived. The results for the uncatalysed reduction are represented satisfactorily with log I1 = 1.247(±0.522) - 5540(±610)T-1.The catalysed PbS:4CaO:4C mixtures contained 2.5 wt% of ternary (K, Li, Na)2CO3 catalyst. For the catalysed reduction it was found that log I1 = 3.981 (±0.301) -7790(±353)T-1, where I1 (in both relations) is expressed in moles.(g.C.)-1.atm-1.s -I. The catalytic enhancement faclor was found to be quite large in the 1068 to 1262°K temperature range investigated here.

Jan 1, 1991