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By K A Plumb

New structural studies in the Walker Fault Zone of eastern Arnhem Land are integrated with basin-wide reconnaissance observations, made to refine models for the structural evolution of the McArthur Basin and provide new insights into the nature of metal logenetical ly important pre-inversion phases of the basin's evolution. At least five principal events may be identified during the Proterozoic: The Tawallah Group and equivalents were deposited throughout the McArthur Basin during an extensional event. Rifting of an incipient Batten Trough occurred at this time, in a terrain characterised by orthogonal, linked extensional faults. Uplift and erosion of the Tawallah Group accompanied continuing extension and was penecontemporaneous with continuing deposition of the overlying Parsons Range Group, within a precursor to the Walker Trough. Dt (of the Walker Fault Zone) relates to a new rifting event, penecontemporaneous with deposition of the McArthur Group and its equivalents in the Walker and Batten Troughs. This rifting accompanied dextral strike-slip faulting along northerly-trending bounding faults, as a result of northwesterly-directed oblique extension, leading to pull-apart basins. D2 inversion of the Batten and Walker Fault Zones pre-dates deposition of the Roper Group. In the proposed model WNW-ESE directed shortening (D2.), accompanied by folding and thrusting, and by local development of cleavage in the Walker Fault Zone, is seen to be followed by northerly-trending sinistral faulting (D2b), about a SE to ESE-directed compression. D3 is basin-wide and post-dates the Roper Group. It is characterised by conjugate faulting and folding about ENE to NE-directed compression. The latest Proterozoic event to be identified (D4) comprises widespread north-trending strike-slip dextral faulting of Roper Group, coupled with N-S directed thrusting across the Urapunga Fault Zone and Murphy Inlier This is accompanied by late dextral reactivation of NNW to NNE-trending faults in the Walker and Batten Fault Zones.

Jan 1, 1994

By E Forbes, G V. Franks

"This study investigates the dual function of a temperature responsive anionic co-polymer of poly (N-isopropyl acrylamide) (PNIPAM) as a selective flocculant/flotation collector. PNIPAM is used for separating hematite from 50:50 mixtures of hematite and quartz, at a variety of particle sizes. The performance of PNIPAM in this system is compared to that of conventional flotation collectors: sodium oleate and sodium dodecyl sulfate. The results of the study demonstrate that anionic PNIPAM used at 50¦C (above the lower critical solution temperature (LCST)) is the most effective flotation collector for hematite particles in the size range between 10 and 20 ¦m. This is attributed to the increased probability of both particle/bubble collision and particle/bubble attachment through the formation of hydrophobic hematite aggregates. Anionic PNIPAM used at 50¦C also produced the highest hematite recoveries for very fine hematite particles (circa 1 ¦m). However this recovery was completely unselective. This lack of selectivity is partially attributed to the activation of quartz particles by PNIPAM, but is thought to mainly occur as a result of entrapment of quartz particles within the matrix of hematite aggregates.CITATION:Forbes, E and Franks, G V, 2013. Selective separation of hematite from quartz by flotation using a temperature responsive polymer, in Proceedings Iron Ore 2013, pp 381-390 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By T Perera, B Fan, S Thang, T Hsia

Minerals are valuable resources and critical elements for a broad range of biological and technological applications, including technological developments to improve energy efficiency and the global movement to promote a low-carbon economy. However, in order to extract these critical metals, large amounts of waste and toxic chemicals are generated, as well as the use of high energy and large amounts of water consumption. Froth flotation is one of the most commonly used processes to separate and collect high-value minerals, but it still has some limitations, including low flotation efficiency performances using existing collectors and other reagents. Therefore, there is an urgent need to design and develop new metal-specific collectors to more efficiently separate and recover valuable minerals and to allow bulk water recovery from flocculated tailings. In this research, we propose to use our newly designed and synthesised novel collectors derived from a type of vitamin E (α-tocopherol), a relatively inexpensive and non-toxic natural molecule. As a potential collector-building block, α-tocopherol has a long hydrophobic carbon chain that facilitates the attachment to air bubbles during the froth flotation process. In addition, the phenol group of this molecule can be easily modified to incorporate various functional groups for targeting different types of minerals. Furthermore, α-tocopherol can be converted into a monomer for polymerisation by the reversible addition-fragmentation chain-transfer (RAFT) process, which can provide us with polymer based-collectors with high precision control of molecular weight and architecture. So far, small-scale qualitative experiments on α-tocopherol-based collectors have been performed with good results, which indicates the feasibility of these compounds as novel collectors for improved froth flotation processes.

Aug 24, 2022

By S D. Dessureault

In one of North AmericaÆs largest mines, which contains more than six active coal-producing faces, mine controllers must meet the complex challenge of adhering to the mine plan while also ensuring customer quality. Fleet management systems (FMS) provide many different avenues to control production flows, from the faces to the various pit crushers. Nonetheless, mine controllers must balance a variety of factors such as unplanned downs, differing customer demands, their own daily key performance indicators (KPIs) related to equipment utilisation, among others. Deviating from the short-term mine plan is the most common means of balancing the other factors, since adherence to the plan is traditionally only measured during the weekly variance meeting with engineering staff. However, such deviation may be one of the most costly responses, as long-term scheduling issues may arise such as multi-face dead-heading or insufficient stripping. This paper focuses on the development of a system for real-time adherence to mine plan within a control room environment. This system is part of a larger blending-focused, multi-million dollar project with elements of a centralised remote control room, developed at the University of ArizonaÆs Mining Information Systems and Operations Management (MISOM) Mine Control Center (MC2). The mine plan (MPL) component of the overall blending system integrates both historical and real-time FMS data with mine plan requirements directly sourced from original systems (no additional input required). The measures, displayed largely as graphs, have tools to help controllers manage the production to facilitate adherence to the plan. Some measures are designed to motivate crews to perform by inciting competition between crews, softened through a study of the controller culture. The MPL component was deployed at the mine, and the before and after deployment adherence was measured. This paper discusses the technical development of the new tool, its deployment, and an ethnography (study of culture) to understand controller motivation.

Sep 26, 2011

By G Nicholas, S Coward, J Vann, R Wolff, S Jackson, S Moayer, A Bye

"A new approach to mineral project evaluation is described called Scenario-Based Project Evaluation (SBPE). SBPE incorporates well established æscenario planningÆ and æscenario thinkingÆ approaches, which are used extensively in other industries,?most notably the?petroleum industry. While most scenario planning is qualitative and non-probabilistic, the approach described here includes both quantitative and qualitative aspects. SBPE is complementary to optimisation approaches and allows mining firms to build and operate projects that are more robust in the face of adverse changes as well as proactively respond and exploit the upside offered by a realistic assessment of variability. The approach has potential to improve project performance and decrease operational risk. It also has important applications for currently operating mines.Conventional evaluation of metalliferous mineral deposits uses estimates of metal grades and deleterious attributes in singular æorebody modelsÆ, usually 3D block models, which fail to capture two critical aspects that underpin the realised value of mining projects: the inherent uncertainty of the estimated attributes the spatial variability of attributes, at the scale of mining selection, which impact on downstream processing steps and fundamentally drive realised value. While singular models are appropriate for estimating block averages, conditional simulation (CS) models of the relevant attributes are needed to represent uncertainty and capture spatial variability. Any attributes that can be either built into CS models and/or modelled in the envisaged mining/processing steps, can be evaluated fully through to highly ægranularÆ (ie detailed and un-smoothed) cash flows. A complete view of SBPE relies on selected strategies being tested against plausible æscenariosÆ of factors external to the project and thus outside management control. æExternalitiesÆ captured in such scenarios include market prices, costs and taxes. Via SBPE, project managers may demonstrate that there is material value in preserving or purchasing options that provide future flexibility to respond to the changing externalities or changes in orebody performance. Such flexibility generally comes at a cost but is very difficult to value. It is argued that full value chain evaluation using SBPE can help to value these options for a mining company. A case study for a gold mine is presented.CITATION:Vann, J, Jackson, S, Bye, A, Coward, S, Moayer, S, Nicholas, G and Wolff, R, 2012. Scenario thinking - A powerful tool for strategic planning and evaluation of mining projects and operations, in Proceedings Project Evaluation 2012, pp 5-14 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 24, 2012

By K Verbeken, D Seveno, A Maslov, I Bellemans

Recycling and decarbonisation current metallurgical processes is key for our planet’s future and in both cases, digital twinning will play an important role. However, the various modelling techniques being used for digital twinning require a lot of input values on variables such as viscosities, diffusion coefficients and surface energies that need to be known as a function of temperature, atmosphere and composition, but which are not widely available, such as in databases, for molten slag phases. The need for more accurate data on physical slag properties is clear and will be extremely relevant for making more realistic and quantitative simulations. Some of these properties are difficult to determine, which is inherent to the very high pyrometallurgical temperatures. Therefore, this work focuses on some aspects related to determining electrical conductivities, viscosities and surface tensions of slags via a combined experimental-modelling method. Besides experimental work, molecular dynamics (MD) simulations can be used to investigate oxidic slag physical properties. With MD simulations, one can follow the time evolution of a system (consisting of atoms or molecules) by integrating Newton’s equation of motion. The input for an MD simulation mainly consists of a force field as well as initial positions, velocities and mass of each atom. The determination of the transport properties in existing literature of MD simulations in oxidic systems, is typically based on incorrect assumptions. For example, to determine the ionic conductivity, the frequently-used Einstein-Stokes equation fails to take into account all ionic types and neglects correlated motion. Furthermore, the viscosity determination via the Einstein-Stokes formula also assumes independent motion of the different ions. This paper gives a brief overview of the opportunities and challenges related to the use of MD simulations for oxidic slag systems.

Jun 19, 2024

On account of the increased work required from the assay office, owing to the large additions which have been made to the smelting and superphosphate plants during the last few years, it was found necessary to build a more extensive and up-to-date assay office than the one that had been in use since the starting of the works some twenty years back.A site was chosen adjacent to the main office, so as to be free from smoke and dust.. The building is constructed of red brick, the over-all dimensions being 109 ft. x 37 ft. The roof is of fibrous-cement slates, 31 ft. high, with a two-to-one rise, and overlaps the walls to the extent of 4 ft. 6 in. on all sides.Special care was taken to give light to all working benches, fume cupboards, and balance rooms. The main chemical room occupies the entire western end of the building, and the fire room the entire eastem end. Between these two rooms are the superphosphate, refinery, and gold-parting rooms on one side of the central passage, and three balance rooms, general office, and cloak room on the other side. The height of the roof affords ample space above these central rooms for storage purposes, and also maintains a fairly even temperature. The ceiling of the main chemical and fire rooms is carried immediately under the slates, which gives a total height in the centre of about 25 ft.

Jan 1, 1918

By Agrawal A, Joshi A

Mochia mine, in culmination of depillaring operations, fired India's largest underground pillar blast consuming 145 tonnes of explosive and yielding 0.55 million tonnes of ore in June 1994. To protect main mine structures (situated at a distance of 250 to 350 m from the blast site) from resultant ground vibrations, the charge per delay was restricted to 2300 kg. The post-blast observations revealed that no damage was caused to these structures. However, the damage assessment survey of the mine workings situated in close proximity revealed a general trend in consonance with the distance from the blast and found to be well correlated with peak particle velocity.

Jan 1, 1995

By A E. McElnea, M A. Martens

An 18-month project was undertaken to test the effectiveness of controlled daily tidal exchange augmented with hydrated lime treatment of surface waters as an approach for remediating a severe acid sulfate soil disturbance at East Trinity, Cairns, north Queensland. Actual acid sulfate soils were producing hazardous levels of acid and heavy metal contaminants and degrading approximately 720 of the 940 ha East Trinity property and the adjacent foreshores. A government-led research team established a series of research projects with the aim of characterising the site (soils, water, terrain) and testing the effect of the lime-assisted tidal exchange management strategy on soils, water, sediments and biota.

Jan 1, 2003

The Argyle Diamond Mine came on stream late in 1985 as the world's largest diamond producer in terms of carat output. The design of the process plant, including the heavy medium separation (HMS) facility which provides the initial stages for separation of diamonds from gangue, evolved over a lengthy period of feasibility study and site investigation into the final form described in this paper. The commissioning was carefully planned and co-ordinated, and culminated successfully with handover of the plant on schedule and within budget. Problems encountered during .within were minimal and since then the plant has achieved greater than design throughput during its first year of operation. Darvr_ontmn

Jan 1, 1987

By A Castleden, G Cavanough, M Kochanek, J Cunningham

ROES« is a proposed new mining system for underground hard rock mines. Ore is accessed from within a shaft, which is located close to or within the stope, and pitched either vertical or within approximately 20 degrees of vertical. The shaft is designed to exclude personnel entry so production drilling and explosive placement is done using remotely controlled or automated machines. Routine remotely controlled survey of the shaft, stope back and broken rock within the stope is typically done following each blast. The survey may include excavation geometry, rock fragmentation and geotechnical characteristics. Blastholes are surveyed before placement of explosives. This provides mine operators and engineers with real-time data, allowing them to monitor production performance and risk factors so that they can make rapid changes as required. ROES« is designed to apply to open stoping or sublevel caving situations either in disseminated, geologically defined, thick tabular or narrow vein orebodies. The technologies developed for ROES« will also have potential applications to block caving operations to reduce the risk of frozen ore and poor fragmentation. In a typical sublevel open stope application, ROES« will reduce the amount of stope-associated development by about half and therefore will allow ore to be brought on-stream sooner and at significantly reduced cost. Other savings are expected to flow from the centralisation of mining activities and operational data, reduction in mining fleet, reduction in ventilation requirements, improved occupational safety and reduced mine complexity. CSIRO and Orica Mining Services are developing the required technology and AMIRA is seeking sponsorship for a project to trial the mining method. This paper details the ROES« method, expected benefits and applications and includes typical stope and mining block designs and design requirements.

Jan 1, 2008

By West RF, Pooley RH

An underground mine, a treatment plant and supporting facilities have been constructed at Lebong Tandai in Sumatra, Indonesia by PT Lusang Mining. Throughput is initially 50,000 tonnes per annum of ore with an inbuilt capability to expand to 100,000 tonnes per annum. Construction proceeded in parallel with design work on a tightly controlled critical path schedule. The very remote location of the mine, the difficult access and the fact that equipment was imported from many parts of the world presented a challenging project management problem. The transport system, which involves road, river and rail and support facilities on site had to be brought into full operation prior to the arrival of major equipment. Mine development involved the reopening of the old access drives and workings, refurbishing two shafts and the haulage system together with redevelopment of old stoping areas and the opening of new stoping areas. Ore production is now from three main areas using shrink and underhand stoping methods. Ore breaking and drive development is with conventional airleg mounted rockdrills and ANFO explosives. Exploration to locate and develop new reserves to replace ore mined is an ongoing activity.

Jan 1, 1986

The efficient design of carbon-in-pulp (C.I.P.) plants involves the integration of both process engineering and design engineering.Many recently constructed plants have not recognised the above interrelationship, and as such have incurred higher capital and operating costs than were in reality necessary. This has been compounded in some cases by slavishly following the design of plants where process conditions are different for the ore characteristics in question, thus perpetuating design errors that finally become industry "accepted practice".In the paper that is to be presented the unit operations of crushing, grinding, classification, leaching, adsorption, desorption and electrowinning in C.I.P. plants will be discussed with reference to the integration of process and design engineering.

Jan 1, 1986

I've talked a number of times in the past year or so to audiences like today's about culture -about thinking of it, understanding it, respecting it. So, rather than talk just yet about your laws for mining on Aboriginal land and the successes some of us and some of you have been able to achieve, I'd like to first of all talk about cul- ture as I understand it. Anyone who proposes any kind of development on Aborigi- nal land needs to have some basic understanding of what we, the traditional owners of that land, are about. Without that under- standing, you will find difficulty in coming to terms with us. Many people have experienced this difficulty and, unless we can do something about it together, many more will continue to find it.

Jan 1, 1988

Between, 1980 and 1984, the demand for non- ferrous metals in the free world grew annually by 1.5 per cent for copper, 0.4 per cent for lead, 1.4 per cent for zinc, and 2.5 per cent for nickel. The growth rate decreased substantially compared to the rate experienced before 1980, and was far lower than the GNP growth during the corresponding period. The main reasons for this are considered to be 1. resource-saving efforts by industrialized countries resulting from the first and the second oil crises, 2. saturated demand for durable consumer goods, and 3. substitution of non-ferrous metals by new materials such as optical fibers.

Jan 1, 1986

This paper discusses the requirements for a successful simulation modelling study, and the steps involved in the modelling process. Advantages and disadvantages of simulation are described, and a case study highlights how not to go about it. Two other case studies, for a decline truck haulage and a block caving production operation, are used to illustrate the types of variables whose impact may be investigated. Typical results are presented to indicate the sorts of presentation styles the author has found useful for conveying study results to project sponsors. Standard spreadsheet charting techniques can be very useful in this respect, but the possibilities are limited only by the imagination of the study team.

Jan 1, 2000

By Niemann G

The paper addresses certain mining provisions of the Aboriginal Land Rights (Northern Territory) Act 1976 and the development of Mining agreements negotiated pursuant to Section 43 of the Act. Difficulties for miners and Land Councils alike arising out of the operation of the Land Rights Act will be discussed. Possible scenarios for the resolution of these difficulties will be proposed.

Jan 1, 1984

By P Joyce, D R. Cooke

The Dinkidi Cu-Au porphyry deposit is situated in the Caraballo Range of North Luzon, Philippines. Although comparatively small, Dinkidi has unusually high gold grades with drilling by Climax-Arimco Mining Corporation delineating a 110 Mt orebody at 1.2 g/t gold and 0.5 per cent copper. The magmatic-hydrothermal evolution of Dinkidi records a distinctive switch in mineralisation from an early orthoclase-dominated Au-rich assemblage, typical of alkaline porphyry systems, to a later quartz stockwork Au-Cu rich assemblage typical of most calc-alkaline to shoshonitic porphyry systems. The early orthoclase-dominated stage is associated with the intrusion and crystallisation of a variably-textured clinopyroxene-syenite dyke that contains high-grade (5 - 20 g/t) gold mineralisation. We consider this dyke to be a Cu-Au porphyry analogue to the pegmatites found in granitic systems. Dinkidi is hosted within the Early Miocene Didipio Igneous Complex. This alkaline igneous complex is comprised of early unmineralised gabbros (pyroxene-plagioclase cumulates), clinopyroxenites (pyroxene cummulates), diorites and monzodiorites that have been intruded by a large, weakly mineralised monzonite pluton. The Dinkidi deposit is located at the southern margin of the monzonite pluton. Mineralisation is hosted within a composite monzonite stock. Within the stock, an 800 metres by ~200 metres (plan section) elongate monzonite stock (Tunja Monzonite) predates and hosts the bulk of the Au-Cu mineralisation. This has been intruded by the thin (10 to 30 m wide), highly mineralised variably-textured magnetite- and clinopyroxene- phyric syenite pegmatite (the Balut Dyke). The youngest phases of the composite stock are leucocratic quartz-monzonite porphyry (Quan Porphyry) that grades texturally, in its core, into a post-mineralisation crystal-crowded quartz-syenite (Bufu Felsite). The late-stage Bufu Felsite is inferred to be the source of much of the Cu-Au mineralisation. The Didipio Igneous Complex has intruded a sequence of Late Oligocene alkaline andesitic lavas and volcaniclastics and overlying potassic dacitic lavas. Whole rock geochemical analyses indicate that the intrusions and the potassic dacite lavas in the surrounding region are co-magmatic. Five main stages of hydrothermal activity are recorded at Dinkidi. An unmineralised K-silicate (biotite-magnetite) alteration assemblage formed during the intrusion of the Tunja Monzonite stock. The diorites surrounding the stock display intense selectively pervasive biotite and magnetite alteration and are cut by an extensive network of orthoclase veins and monzonite dykes. The orthoclase-dominated assemblages of Stage Two carry substantial high-grade Au mineralisation and are associated with the intrusion of the Balut Dyke. The emplacement of this unusual dyke is associated with emplacement of pegmatitic clinopyroxene-orthoclase-magnetite¦sulphide dykes, localised orthoclase flooding along the margins of the dyke, and subsequent emplacement of an extensive orthoclase-actinolite-bornite¦chalcopyrite-fluorite stock-work, and development of widespread selectively pervasive actinolite alteration. The main stage of Au-Cu mineralisation at Dinkidi is intimately associated with the intrusion and initial crystallisation of the leuco-monzonite porphyry (Quan Porphyry) and emplacement of a quartz stockwork followed by carbonate-sulphide deposition and intense vein-related sericite and carbonate alteration assemblages. The quartz stockwork formed synchronous with the deposition of the æBugoy QuartzoliteÆ, a very coarse grained mosaic of quartz-orthoclase-perthite along the walls and top of the crystallising intrusion. Stage 3 was terminated by crystallisation of the distinctively vuggy Bufu quartz-syenite phase in the core of the intrusive, with associated antiperthite veins, and the subsequent explosive brecciation of the roof of the intrusion, forming a quartz-fragment breccia from the Bugoy Quartzolite. Retrograde metasomatism during Stage Four was intimately associated with the emplacement of extensive, late-stage carbonate, silica and zeolite veins and widespread selectively pervasive carbonate alteration. The last hydrothermal stage at Dinkidi, Stage 5, is comprised of strong selectively pervasive clay alteration and is associated with fault-related brecciation of the Dinkidi stock.

Jan 1, 1999

By P Minkkinen

"Pierre Gy showed in his early works that the results in estimating the variance of the mean value of continuous lots depends on sampling mode (random, stratified or systematic), except in the theoretical case that the measurand is randomly distributed in the lot. The experimental variance estimate calculated from samples taken from the lot is independent of sampling mode but depends on sample size and the type of the lot heterogeneity. Variography can be used to estimate the variance of the lot mean for different sampling modes.Gy also defined weighting error, which is made if a simple average is calculated from the assays of samples taken from a continuous object (eg from a process stream) where the flow rate varies with time and is correlated with the concentration of the analyte in the stream.The effect on sampling uncertainty of the three sampling modes and their interaction with the following factors in estimating the uncertainty of the mean concentration is studied using simulated lots, and lots having heterogeneity patterns similar to those of real data sets, including the effect of: the type of heterogeneity (random, grading and clustered heterogeneity patterns) increment size and number employing composite sampling weighting error. CITATION:Minkkinen, P, 2017. Dependence of the variance of lot average on the sampling mode and heterogeneity type of the lot, in Proceedings Eighth World Conference on Sampling and Blending, pp 319–330 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 9, 2017

By Percival T. J

Precious metal deposits containing fine-grained disseminated or dispersed gold-silver form by reactions between metal-bearing hydrothermal fluids and sedimentary host rocks. Host rock permeability and chemical composition exert a primary influence on the fluid movement necessary for any primary dispersion halos to form around ore bodies, and determine whether a disseminated style orebody itself will even form. Where the mineralized rocks are relatively unfractured the margins of the orebodies exhibit abrupt decreases in gold content, and strong corresponding decreases in the contents of other metals. Primary dispersion patterns of this type are difficult to recognize and commonly are only a few meters (or less) in width. If the host rocks were well shattered and broken before mineralization, remnant amounts of the hydrothermal fluids may be dissipated in fractures lateral to or above the ore zones. This causes geochemical anomalies to form with clays and silt- size silica within the fractures over distances of up to at least 30-50 meters away from the main orebodies. The tendency for large primary dispersion halos not to form around these deposits explains the disappointing results from so many drilling programs where no multi-gram gold-grade material was even found: if large areas and apparent large volumes of rock contain one gram or less gold that likely is the "orebody" and not a halo effect around high grade mineralization.

Jan 1, 1988