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By Millen M. J, Rainey S, Sowerby B. D

The control of size reduction in grinding machines and circuits may be enhanced by a continuous and accurate measurement of the particle size of solids in appropriate process streams. This paper presents a brief review of commercial particle s

Jan 1, 1997

By Braes J. R, Neale J. R

The New Broken Hill Consolidated Limited (NBHC) mine currently produces 1.42 million tonnes of silver, lead and zinc ore annually. All of this ore is treated by the NBHC milling ccx[plex. This paper describes the crushing, grinding, flotation and filtration circuits used in the treatment of this ore and lists the major items of equignent used in these circuits. Metallurgical results, manning levels and consumption rates of reagents and grinding media are shown.

Jan 1, 1983

By Linge HG, Klauber C

The key element in the carbon-in-pulp process for gold processing is the loading of dissolved Au(CN)2 from solution onto activated carbon. The mechanism and kinetics of this step have been examined by solution adsorption-desorption and X-ray photoelectron spectroscopy for both coconut derived activated carbon and peat-based activated carbon. The results show that these carbon types have the same mechanism and kinetics of adsorption. There is no contribution to the bonding from carbon-oxygen functionalities on the carbon surface, as has been invariably supposed in all previous theories for the mechanism of the reaction. It is shown that Au(CN)Z is reversibly adsorbed intact on and parallel to the graphitic planes of the carbon with the formation of a weak carbon-gold n-donor bond. The kinetic measurement of carbon gold loading reactivity is discussed and use of the Murdoch equation for this test is critically assessed.

Jan 1, 1989

The large El Cerrejon coal open pit in north east Columbia has been developed over the last decade in a remote, entirely new mining area with hitherto unskilled inhabitants. Now over 200 pieces of heavy equipment operate with high reliability and availability due to successful theoretical training and skill improvement programs tuned to the specific reliability needs of the worksite and environment. The process of continuous improvement adopted promises further competitive advantages of the project.

Jan 1, 1991

By Giannini L. M

Optimisation techniques, based on the block model, for solving the optimum pit limit problem were discussed in an earlier paper. Of the available techniques the one based on graph theory proved to be the most attractive. In the graph theory model the vertices represent blocks and the arcs represent the mining restrictions. For large ore-bodies direct application of the graph theory method poses considerable computational and storage problems. Techniques for easing the computational effort by reducingthe problem size were introduced in an earlier paper. Further, significant computational savings can be made by exploiting the structure of the graph. This is done by building the graph up level by level and successively applying the graph theory algorithm to reduce the number of blocks. In building up the graph in this way one needs what is called a "search pattern" to indicate which arcs are to be added as new vertices are introduced. Moreover, as it is essential to keep the number of arcs to a minimum it is necessary to establish a "minimum search pattern".The problem of determining minimum search patterns for any block model and for any wall slope restrictions has not been considered in the literature.The objective of this paper is to present a complete solution to this problem and to discuss, through typical case studies, the application of the associated software developed.

Jan 1, 1988

By Sivell W

We discuss the origin of the Patuki ophiolite complex and the Dun Mountain ultramafics of Middle Permian age in Nelson, New Zealand. It is shown that the Patuki volcanics have strong affinities with tholeiites of mid ocean spreading ridges transitional to alkaline basalts similar to those from fracture zones and ocean islands. At D'Urville Island, typically pillowed alkaline basalts enriched in rare light rare earth elements (LREE) - ophitic spilites - are associated with LREE-depleted (N-MORB-like) tholeiitic spilites with intergranular textures. The metabasalts are associated with a wide variety of sediments, and with sediments are intruded by conformable sheets of serpentinite. Coarsely crystalline mafic and plagiogranitic rocks signify vents and magma chambers, and we propose that the group developed as ocean crust from a slowly spreading mid-ocean ridge, transform association, overwhelmed at intervals by volcaniclastic sediment. Detailed mapping at a scale of 1:5000, and stratigraphic and geochemical development and structural coherence, show that the group is not melange in the Franciscan sense. The Dun Mountain Group, of serpentinites, peridotites, dunites, gabbros and other rocks, intruded the upper Patuki Group as a linear series of aligned pods and sheets. They carried up with them tectonic inclusions of older rock, which were metasomatised, and altered wall-rock, and one low angle dike passed several hundred metres into overl~ing sediment, at moderate temperatures (500 C). The rocks did not act as a floor (and alleged source) for the Patuki, but partly post-dated and were emplaced into Patuki.

Jan 1, 1987

By R Puglisi, G McPhail, B D. Jilbert

The increased international focus on sustainable development and cost improvement, coupled with the unpredictability and adverse impact of droughts in Australia and globally, has highlighted the critical need for responsible management of water within the minerals industry. The Rio Tinto Technology Group recently initiated a priority program to examine how water management practices could be improved within the GroupÆs spheres of activity. Rio Tinto Technical Services (TS), the technical services consulting group of the Technology Group, has for many years been undertaking water management reviews and assisting group operations with the development of responsible water management strategies and plans. Rio Tinto therefore requested that Rio Tinto Technical Services develop a world-class approach to mine water management that will drive improvement in strategic assurance and operational efficiency of water at the companyÆs managed operations across the world. The initiative, known as æExcellence in Water ManagementÆ, includes the selection and use of state-of-the-art management, technical tools and methodologies to strive for best practice. The Rio Tinto Technical Services approach facilitates a consistent and objective assessment of performance across the entire spectrum of complex water management issues within a mining operation, from initial exploration through to decommissioning and close-out of the operation. Based on this rigorous assessment, detailed action plans can be developed, prioritised and scheduled for subsequent implementation. This paper presents the progress and experience gained to date in the æExcellence in Water ManagementÆ program, demonstrated by means of a pilot study conducted at Northparkes Mines in New South Wales.

Jan 1, 2003

This paper looks at the various stages of development of open stope drilling techniques. Due to the structural nature of the orebodies mined by open stoping it has been necessary to review mining methods. In-the-hole hammer drilling proved to be the solution to many problems encountered in horizontal percussion drilling.

Jan 1, 1977

By D Craw

Quaternary warping and uplift of antiformal schist ranges in Central Otago, New Zealand, has resulted in recycling of alluvial gold from widespread, generally weakly auriferous, Miocene fluvial gravels that unconformably overlie the schist, into aprons of fan sediments along the range margins. Basement erosion during uplift has been limited and so gold input from sparse gold-bearing quartz veins in the schist has been relatively minor. In an eluvial cycle on the slopes of the ranges, chemical remobilization of gold occurs during oxidation and erosion of the Miocene sediments. The typically fine-grained (300 - 400 ¦m) gold undergoes chemical modification and grain size enhancement of up to two orders of magnitude, and much of it is redeposited in a large number of relatively small alluvial fans along the range margins. Groundwater mobility within the fans results in minor additional gold mobility and grain size enhancement. During range uplift, a small number of relatively large axial streams and rivers have developed in structural lows between growing antiformal folds. Axial streams 'gather' their flow from consequent streams draining the folds, and flow parallel to a range axis for some distance before cutting across it in an antecedent gorge. The axial streams rework alluvial fan sediments along the range margins, and transport mainly fine-grained gold from the fans along the ranges. This gold is redeposited where the axial streams emerge from a range in the neighbouring structural basin. Axial streams drain relatively large areas of range surface, and thus reconcentrate significant quantities of gold in a small number of relatively large fans and fluvial deposits. The processes of gold collection and re-deposition by axial streams are essentially the same, regardless of stream size. Coarse-grained gold produced by chemical remobilization, is more difficult to transport in fluvial systems, and thus remains in close proximity to eluvial environment where it was formed.

Jan 1, 1995

By Fink ST

Management requires up-to-date information on the activities of an enterprise in order to maintain control and to assist in decision-making and planning. In today's environment it is essential that this information is immediately available and in an easily assimilated format. If this is not the case, management is forced to make decisions based on intuition and past experience. At Mt Newman Mining Co, a computer application has been developed and implemented with the objective of providing this type of information to management. The Key Parameter Reporting System (as the application is known) allows for daily (constant) on-line capture of selected production statistics, safety statistics and free format textual comments relating to topics such as industrial relations, major maintenance and other pertinent news. Information can be retrieved,'and displayed or printed in either a tabular or graphical format. All senior managers have colour visual display units in their offices for immediate access to the system. Access to selected sensitive information is controlled. All company staff are able to retrieve unsecured information from the system via visual display units installed in all company Locations.

Jan 1, 1983

By J Rowland, B Belle, M Webber

The Australian underground coal industry has experienced substantial improvements in longwall productivity and, as such, the methods of providing a safe and productive mine environment have needed to evolve and develop. Whilst the primary method of controlling atmospheric conditions is by airflow it has become impracticable or impossible for the majority of Australian longwall mines to contend with all environmental hazards with primary ventilation alone.If the ventilation circuit cannot provide a safe and productive mine environment at an acceptable cost and circuit duty then supplementary controls are required. Examples include pre-gas drainage, post-gas drainage, gas utilisation, refrigeration and innovative dust control systems. Of the 21 longwall operations surveyed in Australia, there were 13 in New South Wales and eight in Queensland.This study represents a timely opportunity for the industry to examine the primary and supplementary ventilation systems implemented in Australian longwall mines and to discuss how to equip the industry to successfully face the future of underground longwall ventilation management in Australia.CITATION:Webber, M, Belle, B and Rowland, J, 2017. Australian longwall ventilation systems, in Proceedings Australian Mine Vent Conference 2017, pp 301–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By Watson D. F

Armstrong's (1983) criticisms of PhiIip and Watson's (1982b) note on optimal drilling patterns are based on misinterpretation, supported by errors in geometry. Furthermore, Armstrong argues conceptually from the perspective of Matheronian geostatistics, as does also Rudenno (1983a, b). Thus, both authors embrace a global, probabiIistic method of assessing spatial data sets, an approach that must be contrasted strongly with local, deterministic interpolation methods. Some of the important assumptions of geostatistics are outlined and the non-unique nature of the method discussed. A probabilistic approach can be judged appropriate when exploration data are erratic, or known to be unreliable, or when extrapolation is desired. Where data are treated as exact, kriging can give the most biased result if tested against other interpolation methods. We reiterate our previous conclusion that the equilateral triangular grid is approximately 30 per cent more efficient (in terms of numbers of drill holes) compared with a square grid for the same maximum interpolation distance. This is simply due to the improved isotropy of sampling. New, locally-based, deterministic methods for computing ore reserves seem to be required.

Jan 1, 1984

The West Fork project is located in Reynolds County, Missouri, in the mineralized zone referred to as the Viburnum Trend. The West Fork orebody has a calculated ore re- serve of 13 600 000 tonne (15 000 000 st) con- taining 5.5 per cent lead, 1.2 per cent zinc, and recoverable values of copper and silver. A total of 64 600 tonne (71 200 st) of lead concentrate and 11 300 tonne (12 500 st) of zinc concentrate will be produced annually. The mill was designed to operate at an average capacity of 3450 tonne/day (3800 st/day), based on a 95 per cent availability factor. The mill will operate 24 hours a day, 5 days a week, with maintenance performed, as needed, on weekends. The mine will operate on an identical schedule; but the underground, pri- mary crushing will operate on a six hour/shift, three shift/day schedule. The 1.07m x 1.22m (42in x 48in) jaw crusher will produce a minus 20cm (8 in) material at an average rate of 191 tonne/h (211 st/h). The jaw crusher has almost twice the throughput capacity required, but the decision to install that size of crusher was based on the need to handle over sized rock in the ore.The coarse crushed ore will discharge into a 180 tonne (200 st) skip pocket, which will allow up to a one hour surge capacity prior to hoisting. Hoisted ore will discharge into a 900 tonne (1000 st) storage bin located adjacent to the headframe. The skip pocket and coarse ore silo comprise the total ore storage capacity. The concept of having no intermediate fine ore storage between the secondary crushing and grinding sections was borrowed from the Brushy Creek Mill of St. Joe Minerals, which operates adjacent to the West Fork property. Integration of the secondary crushing and grinding circuits has worked ' successfully for years at the Brushy Creek Mill. The most obvious advantage to eliminating the intermediate fine ore storage is'capital expen- diture savings. The capital expenditure savings include the cost of silos, feeders, and the cost of additional conveyor length and eleva- tion. Savings in operating costs will also be gained, particularly in reduced maintenance costs. Other factors which influenced the decision to eliminate fine ore storage were the simplicity of the secondary crushing sec- tion and the limited area available for con struction of the facility

Jan 1, 1978

Within the Business Process Improvement Program initiated at Placer Dome during 2003 was the Business Performance Management Project (BPM).BPMÆ s aim has been to extract productivity improvements from individual business units by providing a model for implementing leading practice based management process within the Placer Dome Group, sharing management best practice, injecting new management techniques and instilling a continuous improvement culture. The installation of an underground dispatch system has been a key component of the BPM project at Osborne Mine.Information capture and analysis allows for corrective action to be planned and executed before there is a material impact on the performance of a business unit. This paper briefly describes the principles and practices of effective business performance management, the four processes of a management operating system namely; strategic and tactical planning, implementation and reporting. The identification of business drivers, their measures and associated key performance indicators is discussed. The benefits of an underground dispatch system at Osborne with respect to safety, production and maintenance is described along with the installation process within the mining department that included its configuration, resourcing and roll out.

Jan 1, 2005

By Ross T. J

Renison Limited operates an underground tin mine employing both cut and fill and open stope methods, at Renison Bell on the west coast of Tasmania. Mining in the region commenced in the 1890's. Development of the current mining operation commenced in 1965. The ventilation system used at Renison in its present configuration is a function of current mining methods, orebody characteristics and prevailing Tasmanian Department of Mines Inspection Regulations.

Jan 1, 1988

By V A. Diemar

The Chatree Gold Project represents a greenfields discovery of metallurgically clean shallow gold mineralisation in a logistically simple terrain. Total Measured, Indicated and Inferred Resources are currently 31 tonnes of gold and 160 tonnes of silver. Gold occurs in an adularia-sericite epithermal system within quartz-calcite-adularia veins, breccias and stockworks. Host rocks are volcanic arc porphyritic latite-trachyte flows, their pyroclastic equivalents and volcaniclastics of upper Permian to upper Triassic age. The mineralisation was deposited in dilated zones during repeated reactivation of pre-existing structures. To-date five mineralised prospects have been defined by drilling with three reaching JORC Code Mineral Resources status. The project is in its definitive feasibility stage and is anticipated to be in construction during 2000.

Jan 1, 1999

By S K. Michelic, N Preisser

For certain applications, steels have to feature a very distinct and well-defined level of cleanness in terms of the number and composition of non-metallic inclusions. Therefore, one crucial aspect of steelmaking is removing and controlling said non-metallic inclusions during the process. Particle removal during ladle refining comprises three stages, namely: 1. Flotation 2. Transport through the steel/slag interface 3. Dissolution of the particle in the slag. Only if all three stages are completed the particle can be considered as fully removed from the steel melt which, in turn, leads to the slag being one of the most influential parameters for inclusion removal and control. Depending on the composition of the particles and the slag, the dissolution can be controlled by different mechanisms. This study focuses on the diffusion-controlled dissolution of solid oxidic particles in slags. For this, a model of particle dissolution has been developed. For modelling diffusion, either the differential equation following Fick’s second law can be solved, or an analytical solution to this equation valid for stationary interfaces can be used. Both approaches allow for calculations of concentration profiles of the dissolving species in surrounding slag. From this, the mass flux can be derived, which finally leads to calculating the boundary layer velocity due to considerations of mass balance. In this work, both methods as well as results of dissolution experiments using High Temperature Confocal Scanning Laser Microscopy are compared. This research aims to provide a framework for diffusion-based dissolution modelling in further expanding the understanding of particle dissolution in secondary metallurgy.

Aug 21, 2024

By C G. Ferguson, S L. Makin

The Cawse nickel project is a new generation pressure acid leach (PAL), solvent extraction and electrowinning process used to produce LME grade nickel metal and cobalt sulphide concentrate containing 40 per cent cobalt by treating nickel and cobalt oxide ores from a lateritic ultramafic profile. The project is located 50 kilometres NW of Kalgoorlie in Western Australia. The commercial success of the Cawse nickel operation is dependent in part upon the ability of the principal ore type to be beneficiated. A simple process of rejecting lower grade material on the basis of particle size achieves this. The process is called upgrading and allows subgrade material to become commercial ore grade and also allows higher ore grades to be processed in the early parts of the operation. The success of the upgrade process is dependent upon the physical and chemical properties of the ore being processed and the nickel grade of the ore. The upgrade ore type represents >80 per cent of the Cawse nickel resource and is hosted mostly within a limonite unit, represented by goethitic clays in the upper saprolite zone. In the upgrade processing circuit the ore is crushed and slurried. It is then passed over a series of screens that remove all material over 0.5 mm. This ensures that coarse material is removed from the main ore stream. Upgrade is reliant on selectively rejecting lower grade or barren material, which can include silica, magnesite and relict saprock. To predict leach feedgrade, the grade control estimates the head grade and upgrade percentage for all ore delivered to the run of mine ore pad. To do this reverse circulation (RC) drill holes are logged for ore type, assayed for a range of elements and undergo simulated upgrade testwork. The percentage and grade of material rejected through the upgrade circuit has the most influence on upgrade per cent. This reject is determined by the physical properties of the rock mass and drum scrubber parameters. The correlation between nickel upgrade and reject can be established to predict upgrade from the known mass reject. Parcels of upgrade ore milled to date closely follow projected correlation trends. Upgrade circuit results have been excellent, with average nickel grades upgrading by 34 per cent, cobalt by 23 per cent, with 55 per cent mass passing.

Jan 1, 2000

By Smith M, Milton T, Pitt G

High levels of contamination (non magnetics) were present in the magnetite medium of the D.M. cyclone circuit. Attempts were made to minimise the amount of undersize (-lmm) material in the D.M. cyclone feed by improving initial desliming and examining those factors that contributed to any overall reduction in desliming efficiency. Circuit density control was improved and a system of continuous contamination monitoring implemented. A brief description is included of the major alterations to circuit control philosophy. The significant improvement in overall D.M. cyclone circuit performance is outlined.

Jan 1, 1987

For some time the-mining industry has been criticised, completely unjustifiably, by certain people who style themselves conservationists but are actually preservationists. The criticism of the mining industry - and indeed all developmental industries has an emotional background and is not supported by facts. Some claims have been so disturbing that the Australian Mining Industry Council considered that the industry should do more in stating its position and attitude than has been done to date. It was therefore decided to request the Australasian Institute of Mining and Metallurgy (which is a technical organization) to join with it in presenting this seminar so that the subject could be examined on a scientific and factual basis, removed from the pressures of, emotion, and so that the media and the public could be presented with some basic factual data and, I trust, convinced of the soundness of the industry's attitude and policy. Many of the individuals in the mining and metallurgical industry are men who chose mining as a career because the location of mines gives an opportunity normally available only in the more remote areas. "These men do not want to see their countryside despoiled. '-The mining companies they manage and w rk for have accepted a responsibility to the environment which grows out of their close relationship with the earth.

Jan 1, 1971