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By James CH

For drainage sediment to be used as a successful sampling medium in reconnaissance geochemical surveys, the length of any dispersion train from a typical target must be great enough for it to be detected by a widely spaced sampling pattern, and must also be homogeneous enough to avoid it being missed by the unfortunate selection of a random low value sample. Elements which occur in stream sediments in the form of discrete heavy minerals present two special problems in this regard. Since the element is concentrated into a few particles, the medium is extremely heterogeneous, which makes representative sampling impossible unless very large samples are taken, while the high specific gravity of such grains leads to their being concentrated in traps along the stream bed. Several ways of overcoming these difficulties have been suggested. Among these the "schlich" test, in which heavy material obtained by panning is taken for analysis is among the most popular. However, the results of the present study indicate that while this method improves the nature of the patterns obtained, they are still far from satisfactory. Alternative methods of sample preparation, including the taking of light material for analysis, appear to provide better answers to the problem. In the area studied this approach eliminated most of the "noise" associated with the data obtained by other methods, as well as giving an extended dispersion pattern.

Jan 1, 1986

By M Dalm

More and more mining companies are becoming aware of the potential benefits of sensor-based ore sorting and process optimisation. This is reflected by a growing number of analysers that are available for drill hole logging, conveyor belt scanning, ore sorting, slurry analysis, etc. These tools all rely on a specific sensor technology that can be used to detect a material property such as colour, density, mineralogy, or chemical elements. However, all sensors have restrictions on the minerals and/or elements that can be detected or inferred. This is caused by the physical mechanisms behind the technology and depends on mineral concentration and compositional heterogeneity of the ore. Since nearly every ore deposit is unique in composition and characterised by different geological features that drive heterogeneity, no one-size-fits-all sensor solution is available. This makes it difficult for mining professionals to find suitable sensing technologies that can help them solve problems and improve processes for their specific ore types.

Sep 1, 2024

White Cliffs Opal Field is situated in the Parish of Kirk, County of YulguIgra, New South Wales, about sixty miles from Wilcannia, and the River Darling. It is near the southern edge of the cretaceous basin of the interior of Queensland, New South Wales, and South Australia. Twelve miles south-west of the field, at Tarella station, a well sunk at the homestead reached silurian slates at about 127 feet, getting no water but about three miles north-west from the originally discovered and no central portion of the field, a well was sunk by the Momba, Pastoral cmpany, to a depth of 270 feet all the way through the cretaceous beds. At 250 feet a small supply of water was struck, but so much mineralised as to be quite useless. The temperature also was so high that a man could not keep his hand in it and Mr. Hogarth, the Momba Pastoral Company's manager, informs me that so corrosive was the action of the water, that a shovel left down the well for a fortnight, at the time of sinking, was completely eaten away.The well having now fallen in, I have been unable to obtain any of the water for analysis.The western termination of this portion of the cretaceous basin is situated about twenty miles from the present opal field, at which distance the slates, with (probably) devonian sandstones and quartzites resting unconformably thereon, commence to appear. The opal bearing country, as far as at present known, follows a more or less well defined line running north and south towards the northern end of the field, and north-east and south-west towards the southern extremity.

By Blockley J. G, Laeter J. R

The history of the Ph-Cu-Zn mineralisation in the orthampton Block of Western Australia has been further investigated. It was hoped that (1) Rh-Sr studies on partially-remelled granulites, wall-rocks to the dolerite dykes, should date the dolerite intrusion, (2) Rh-Sr data on hydrothermally-altered dolerite should date the sulphide mineralisation, (3) Pb model ages on the galenas might provide an independent dating of the mineralisation, in addition to any geochemical information that might be derived. Only the second dating aim was fulfilled, but the Pb isotope data, when combined with the Rh-Sr data, have permitted deductions about U, Th and Pb abundance changes during the regional metamorphism, and about a possible source of the ore Pb. In detail the following has been found. (1) The partially-remelted granulitic wall rocks yield a scattered whole-rock Rh-Sr isochron which seems not to have been reset by the dyke intrusion (age 1037 ± 146 Ma, with initial Sr ratio 0.7171 ± 0·0054, MSWD = 111). This date agrees well with that reported previously for granulites from another locality; together theyestablish the time the metamorphic period closed. (2) The hydrothermally-altered dolerites yield a Rh-Sr whole-rock date 434 ± 16 Ma, with initial Sr ratio 0.7072 ± 0·0029 and MSWD = 31, taken as referring to the time of Ph-Zn mineralisation. This contrasts with a report of much older palaeomagnetic and K-Ar datings of the dolerite (not less than 550 Ma, possibly older) and suggests that neither the dolerites nor their heat have had any connection with the mobilisation of the Pbscavenging solutions. (3) The Pb isotope ratios of galenas from the ores yield a well-correlated regression which is not amenable to any of the model-age calculations. (4) The Pb-isotopic trends negate any genetic connection between dolerite and mineralisation, but the country-rock granulites could be the Pb source. (5) Combination of the Rh-Sr dates and the Pb data in a "simultaneous isochrons" construct permits the inference of major losses from the system during the regional metamorphism, in the order U>Pb>Th, with substantial homogenisation of the remaining Pb. This left a wide range in local UlPb and Th/U among the source rocks which eventually were scavenged by the mineralising solutions. (6) These geochemical deductions are shown to be compatible with previously-published information on the abundance ofU and Th in the Northampton Block granulites, which are thus seen to be credible as source rocks for the ore lead.

Jan 1, 1985

By S M. Gover

Estimating the probability of failure for embankments is not intuitive. It requires not only an appreciation of the strength of the embankment, but an understanding of the variability and uncertainty in the strength parameters as well. These additional aspects are, in themselves, relatively new to most practicing engineers, and therefore require some discussion.This paper discusses the concepts of probability and uncertainty, and presents a reliability-based numerical experiment, together with a literary study and collation of some of the author’s historical slope stability analyses, to investigate whether a direct relationship between safety factors and probabilities of failure exists for certain levels of uncertainty in strength parameters. In doing so, a useful tool is presented whereby knowing the safety factor of a simple slope or embankment with a consistent level of uncertainty, one can infer an approximate probability of failure.CITATION:Gover, S M, 2018. Linking safety factor to probability of failure, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 384–396 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Sewell L. G, White H. S

OWING to two large falls of ground which resulted in serious accidents occurring towards the end of 1908, it became evident that the "open chamber" system then in use was unsuitable for the conditions existing in the Mount Morgan mine. It will be admitted that in all mining operations the first consideration is the economy of the system adopted, combined with its safety and ability to give the desired output. A sectional system with square sets has been introduced into the mine, in which due attention has been paid to these factors. In this paper a brief description of this system will be given. An outline of those previously used will be included, as it is necessary to understand the conditions which existed in the mine at the initiation of the sectional system. Outside the actual mining methods employed, various points that might prove of interest will be touched on.The square set system of mining has been in use throughout, the stopes in the gold ore in the upper levels of the mine since underground operations were started in Mount Morgan. In the oxidized zone the ore was of a friable nature, and in some cases rImning ground was encountered. In the lower levels the ground became heavier, and although the stopes were for the most part long, wide, high, and irregular, and not sectionalized, no difficulty was experienced in winning the ore, and no accident of a serious...

Jan 1, 1911

By M I. Roberts

Corporate and workplace culture, as many owners, directors, executives and managers know, is by far the most powerful determinant of productivity. It’s much more significant than buildings and equipment. Yet although no one today would build a building or machine without a plan, few leaders have a plan for building and sustaining a safer and more productive culture.Using practical ways, culture can be planned and shaped as desired. Success requires implementing a project plan for changing the systems that drive behaviours that in turn shape attitudes. The combination of behaviour and attitude together with leadership largely shape culture.To improve performance, leaders need to:1. improve the organisational systems that drive behaviour2. action a project plan for improving specific performance metrics 3. demonstrate leadership that is conscious, disciplined, committed and passionate for purposeful use of human energy.This paper explains all three factors in practical ways with operational and corporate examples. It details understanding and applying the power of fundamental statistical analysis tools to recalibrate, focus and drive proactive leadership that takes responsibility for process improvement, supporting people and ensuring accountability.Experience and practical understanding of human and organisational behaviour confirm that the Measurement ? Analysis ? Reporting system combined with conscious leadership is by far the most powerful driver of behaviour. This wisdom produces profound changes in leadership style and behaviour. It develops outstanding leadership to create and sustain a safe and highly productive culture reliably producing consistently high quality products. It is the key to developing accountability, employee retention and a sustained competitive advantage.CITATION:Roberts, M I, 2016. Building safe, productive cultures and leadership, in Proceedings International Mine Management Conference, pp 163-178 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By Collins DN, Hollick CT

Conventional processing of heavy mineral deposits containing radioactive rare earth minerals such as monazite and xenotime may cause industrial hygiene problems through atmospheric dust and contamination of product concentrates. An alternative procedure has been developed in which such minerals are removed from bulk heavy mineral concentrates by flotation with little loss of other economic minerals. With fine ores, recoveries of over 95% have been achieved and with coarse ores over 80%,in both cases at high grade. Several flotation regimes have proven effective. The potential for generation of radioactive dust or product contamination is subsequent processing -is correspondingly reduced.

Jan 1, 1990

By Knight J. L, Baker G

The Wonthaggi coalfield is in South Gippsland, about 90 miles southeast of Melbourne. It is situated on the down-faulted block of the South Gippsland highlands that lies south of the Kongwak fault, between the Powlett River and the sea (Fig. 1). The coal, which is of Jurassic age, occurs in two small, and intensely faulted, limnic basins, that lie on either side of a concealed ridge of Silurian sediments. The coal was first found as thin seams outc1'opping in the cliffs at Cape Paterson, but the seams that are worked at Wonthaggi are concealed beneath a veneer of Cainozoic sands that covers the Jurassic strata, and were found by boring.The c9al seams are worked by the State Coal Mine, which was opened in 1909 to ensure a supply of coal for the Victorian railways, following a prolonged strike in the Newcastle field of New South Wales. The total production from 1910 to June, 1943, amounts to 13,918,800 long tons of coal. The coal seams are faulted to a degree unknown in most coal...

Jan 1, 1944

By Schiller J. C, Both R. A

Base metal mineralisation occurs at several locations within the regionally metamorphosed Kanmantoo Group on the southeastern flank of the Mount Lofty Ranges between Kanmantoo and Strathalbyn, 50 km southeast of Adelaide. Sulphide mineralisation is of three main types (Seccombe et al, 1985):1. copper deposits, at the Kanmantoo and Bremer mines, South Hill prospect and several minor occurrences,2. lead-zinc deposits at Aclare, Wheal Ellen, Strathalbyn, St. Ives, Scott's Creek, and Glenalbyn mines,3. pyrite-pyrrhotite mineralisation of the Nairne pyrite deposit and many other pyritic schist units within the Kanmantoo Group.Syntheses of folding, metamorphism and stratigraphy of the Kanmantoo Group were given by Kleeman and Skinner (1958), Offler (1960, 1963), Offler and Fleming (1968), Marlow (1975), Mancktelow (1979) and Parker (1986). Studies of the general relationships of mineralisation to structure in the Kanmantoo area were given by Grasso and McManus (1954), Mirams (1962), Poole (1969), and Lindqvist (1969).Several conflicting views on the origin of mineralisation in the Kanmantoo Group have been proposed. Thomson (1975) considered much of the mineralisation as a late-stage product of regional metamorphism and he, like Parker (1986) and Lambert et al (1987), stressed the importance of major lineaments as an ore control. However, Lindqvist (1969) and Verwoerd and Cleghorn (1975) tentatively suggested a syn-sedimentary origin to the Kanmantoo copper deposit and Jensen and Whittle (1969) and Seccombe et al. (1985) on the basis of sulphur isotope data proposed a bacteriogenic sulphur source and a sedimentary origin for sulphides in the Nairne pyrite deposit. The latter suggested that most copper deposits represent stockwork, vein or disseminated zones within subsurface vents whereas massive mineralisation at Wheal Ellen and Aclare mines probably accumulated on the ocean floor.This paper presents new geological information on the structural and metamorphic setting of the base metal deposits and attemptsto relate this information to previous regional studies of the Kanmantoo Group. Estimates of pressure and temperatureof peak metamorphic conditions based on silicate mineral stabilities are considered in relation to various silicate and sulphidegeothermometers which have not previously been applied to rocks in the Kanmantoo Group.

Jan 1, 1988

By R Millar

A frequent challenge in mine water management and mine design is estimation of precipitation and extreme rainfall given a short record of site meteorological data. For remote mine projects, typically only a few years of rainfall data are available, which is far too short for estimation of design rainfall event, such as the 1-in-100 year storm. A frequency-paired approach is presented for comparing daily precipitation records from a mine site with a long-term regional station and provides the basis to transpose the long-term record to the mine site. This allows a long-term synthetic precipitation record to be developed for the mine site that can be used to undertake site water balance studies, determine pond storage requirements, assess water supply options and address other surface water management issues. Conventional approaches are based on chronologically-paired data and when applied to daily data generally yield poor correlations between stations. In the frequency-pairing approach, statistical distributions (two-parameter gamma distribution) are fit to daily data from two stations and used to calculate daily and extreme precipitation values for the short-term site (which is typically a mine or other project site). The method is demonstrated using data from two meteorological stations located along the south coast of British Columbia, Canada. Use of a fitted two-parameter gamma distribution (or other distribution) provides a sound theoretical approach to comparing precipitation data from two sites and the basis for transposing a long-term record to generate synthetic precipitation series and extreme rainfall values at mine sites.CITATION:Millar, R, 2013. A statistical approach for deriving project design rainfall, in Proceedings Water in Mining 2013 , pp 273-276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

The Gympie Province is a unique tectono-stratigraphic unit which does not fit into the overall palaeogeographic pattern of the New England Fold Belt (NEFB), and part of it has been proposed as an exotic terrane more closely linked to New Zealand. From E to W the Gympie Province comprises 6 distinct units which can be evaluated as suspect or exotic terranes.

Jan 1, 1990

The paper describes the design of the dilute medium and medium recovery circuits installed at the coal preparation plants at the Cornwall Coal Company's Fingal Mine, and the BP Coal Australia's Howick Mine. These circuits maximize the use of clarified water for rinsing to improve the mass transfer of adhering medium from the coal surface into the carrying liquid, and have been combined with the use of a two stage magnetic separator. The separator utilizes a conventional concurrent first stage and a counter-rotation second stage. This combination results in high medium recoveries during both normal operation, and start up and shut down phases when large quantities of medium can be lost from a conventional circuit. Overall losses using this circuit have been estimated to be, 200g/t, over a twelve month period. Further advantages in plant operation are also obtained, especially steady operating conditions in the centre-tube pump tank, lower slimes contamination of the product, and lower quantities of non magnetics trapped in the separator concentrates. The techniques are particularly suited to incorporation in circuits treating coals containing high percentages of sticky and difficult clays, as are found in the Walloon coal measures.

Jan 1, 1987

By Merry N, Cocks T

The mineral exploration industry is increasingly aware of the importance of the relationship between mineralogical data and geochemical assay results. However, until recently, the cost and time constraints of most techniques for analysing alteration mineralogy have precluded detailed alteration studies. These impediments have been reduced by the development of the Portable Infrared Mineral Analyser (PIMA), a field portable infrared spectrometer that allows rapid (in field) and cost effective analysis of alteration minerals including subtle variations in mineral crystallinity and Composition.

Jan 1, 1995

By J Wall

The use of electronic detonators in civil tunnelling applications, to reduce vibration in small firings has been successfully utilised for a number of years. As part of the mining industry’s commitment to reducing blast damage during the development cycle in underground mining applications, a series of development blasts using e-Dev™ electronic detonators in a typical mining application was conducted at Resolute’s Mt Wright operations in North Queensland in 2010. Results were based on direct comparisons to the current industry standard of non-electric firings as a baseline, with as many parameters as possible being captured during the trial. Development costs are typically high in most underground mines, especially in capital development headings, which are in waste and therefore of no direct economic value, so by being able to accurately fire to design, costs relating to both ground support requirements and volume of material removed, (and therefore haulage required) can be minimised. A direct comparison of overbreak (ground blasted outside of design) and cast (distance rock thrown from blast) was also made during the trial, as well as close monitoring of the drilling accuracy.

Mar 21, 2011

By Ehlert G, Steinlechner E

The paper describes a new process for filtration which combines the continuous operation of conventional vacuum filters with the low final moisture contents hitherto only achievable with plate and frame presses. The increasingly high portion of fine particles causes several problems in the filtration of copper concentrates. One drawback is that remarkable quantities of liquid are attached to the very fine particles because of their specific surface area. Furthermore, fine particles also reduce the size of the capillaries in the filter cake, thus increasing the critical pressure which any filtration system has to exceed to achieve the desired final cake moisture. The maximum filtration pressure of conventional vacuum filters is limited by nature itself and by practical aspects to approximately 0.75 bar. The hyperbaric filter combines the continuous operating principle with an increase in filtration pressure of up to 6 bar simply by placing the entire disc or drum filter inside a pressure vessel. The major machine components and process features are explained in the details of the paper. After extensive research and field testing, 23 ANDRITZ hyperbaric filters, with a total filtration area of 1968 m2 have now been sold. Seventeen of these units (1440 m2) are in commercial use and more units are, on order. Performance data on copper concentrates from plants in Australia, South America, Poland, Africa and North America are outlined in detail. Compared to vacuum filters, generally hyperbaric filters will reduce the final cake moisture of concentrates with 75 per cent

Jan 1, 1993

The Kennedy Siltstone Open Cut provides graded rock for stope filling. Rotary drilling of 310 mm blastholes with a Gardner Denver GD120 is used, and the successful application of an equilateral triangular drilling pattern is described. Charging practices and the development of bulk slurry handling are outlined. Blast monitoring plays an important role in K.S.O.C. drilling and blasting operations. The proximity of nearby residential areas (1300 m) and the Mount Isa Airport (4500 m) necessitates special attention with regard to the minimisation of both air blast and ground vibration levels. The application and control of drilling and blasting parameters has had a direct bear- ing on success of the mining operations and also played an important role in reducing the disturbance to the community.

Jan 1, 1978

By M G. Hawtin

The Rocklands copper project is a multilode, iron oxide copper gold (IOCG) + cobalt mineralised system located in the Eastern Fold Belt of the Mt Isa Inlier. Rocklands orebodies cover a range of oxidation zones from oxide, to supergene and primary. Each zone contains different economic minerals of interest. The supergene zones contain significant amounts of native copper and the primary zones are dominated by chalcopyrite. The juxtaposition of these oxidation zones and minerals make it an interesting mineralisation system.Current mine production sampling collects a nominal 3 kg drill chip sample from a 1 m composite, RC drilled interval. A site specific sampling procedure was needed to quantify introduced sampling error when taking grade control samples. Due to oxidation and mineralogical variation in ore zones we needed to develop a practically achievable sampling methodology that ensures minimum sample mass and sample error requirements are achieved to ensure ‘representative’ samples for all ore types.These issues are planned to be resolved using an experimentally derived method using principles from the Theory of Sampling. This method uses an experimental calibration of parameters K and a for Gy’s fundamental sampling error formula using a modified 32-piece sampling tree experiment to compile sampling nomograms for the primary and supergene ores. This paper demonstrates the process undertaken to improve the quality and standard of existing mine production sampling procedures at the Rocklands operation.Results indicate a sample mass of 5 kg for RC drill chips is appropriate for both the primary and supergene ores to achieve a fundamental error below 0.01 or 10 per cent relative error, which is slightly higher than the existing sampling protocol of 3 kg. An additional experiment is recommended to compile sampling nomograms using the exact laboratory comminution and mass reduction stage information to assess the use of a 3 kg sample. The results also indicate no changes are required to existing sampling protocols when sampling RC drill chips in primary and supergene ore at Rocklands.Sampling nomogram results also provide a useful ‘rule of thumb’ reference guide to other mining and exploration companies to help understand minimum sample mass requirements and sampling error during exploration drilling, resource evaluation and mining production stages when targeting similar IOCG mineralised systems. A sample mass of 5 kg is recommended when RC drilling similarly IOCG mineralised prospects and deposits in the Cloncurry area. Future test work is recommended when additional open cuts become active as well as including resource drilling drill core to provide better three-dimensional sample representivity.CITATION:Hawtin, M G, 2017. Minimum sample mass from reverse circulation grade control drilling at Rocklands copper project, in Proceedings Tenth International Mining Geology Conference 2017, pp 337–346 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Aspinall T. O, Loch R. J, Bell L. C

Design of reshaped spoil surfaces is an important pan of rehabilitation of spoil piles resulting from open-cut coal mining. To achieve the optimum design, it is necessary to make accurate predictions of soil losses from spoil piles. Predictions can be based on data gathered using laboratory and field rainfall simulators and field plots. These data are used to derive input parameters for erosion prediction models. Model input parameters include rainfall erosivity, spoil erodibility, sediment size distribution, runoff, soil loss and peak runoff rate. Model outputs can be used in design and include predicted sediment size distribution and predicted soil loss.The traditional method of gathering input data is monitoring field plots. This method is very expensive, must be done on a long-term basis and is affected by irregular rainfall. Long-term field plots are necessary to obtain data that can be applied to empirical prediction models such as the Universal Soil Loss Equation (USLE).

Jan 1, 1992

By G R. Ballantyne, B Putland, I Lovatt, M Di Trento

The Tropicana Gold Mine, owned by AngloGold Ashanti Australia Ltd (70% owned and managed) and Independence Group NL (30%) is located 330 kilometres east-northeast of Kalgoorlie, Australia, in the newly developed Albany-Fraser Orogen. Following extensive feasibility studies, a high pressure grinding roll (HPGR)-ball milling circuit was selected based on the reduced power requirements and thus reduced operating expenses. The HPGR-ball mill circuit was estimated to require 75% of the energy of a standard semi-autogenous grinding (SAG) mill circuit. Even with an anticipated greater capital cost, the HPGR-ball mill circuit was found to give significantly better financial returns in all cases investigated in the feasibility study. A comparison between the specific energy requirements of the HPGR, crush and SAG based circuits (SABC) from the feasibility work was conducted and the HPGR circuit was found to be considerably more energy efficient. A survey was conducted and the efficiency of the HPGR was similar to both the overall circuit design and the HPGR laboratory results, reflecting the accuracy that is possible for design and operation of HPGR circuits.Between 2015 to 2016, the Tropicana circuit has achieved a 20% increase in throughput from 780 to 930 t/h, and this increase has been maintained in 2017. This improvement can largely be attributed to upgrades to material handling processes, increased HPGR speed and smaller HPGR screen apertures. The result of these changes has been to increase the ball mill capacity by increasing the breakage conducted by the HPGR.CITATION:Ballantyne, G R, Di Trento, M, Lovatt, I and Putland, B, 2017. Recent improvements in the milling circuit at Tropicana mine, in Proceedings MetPlant 2017, pp 73–83 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017