Search Documents

By R Skirrow, E Bastrakov, A Mauger, P

A new rapid spectroscopic core and chip logging and imaging system developed by CSIRO was evaluated by PIRSA and GA on a wide variety of mineralised properties in South Australia, including the Emmie Bluff, iron oxide copper-gold-style prospect on the Stuart Shelf. During a three-month campaign in South Australia in 2003 the system logged over 50 000 metres of core from the State Core Library, company prospects and mines. The new system uses automated core tray handling, continuous visible and infrared spectroscopy, and digital imaging, to characterise and identify dominant mineral species on core, chips and pulps, at spatial resolutions of ~1 cm (spectral data) and ~0.1 mm (image data). The system can log up to 1000 m of core per day and several thousand metres of drill chips. Mineralogy is pre-interpreted using specialised identification software trained on a selected suite of minerals showing characteristic absorption features within the measured spectral range. On core from the Emmie Bluff iron oxide copper-gold prospect, 470 km NW of Adelaide and 80 km SSE of the Olympic Dam Cu-U-Au deposit, the spectral mapping system was able to characterise a number of alteration zones enveloping the sub-economic Cu-Au mineralisation. These consist of distal white mica phases showing decreasing Al content towards mineralisation, a zone of increased iron oxide content in the hangingwall to mineralisation, and a zone proximal and coincident to Cu-Au mineralisation that is enriched in chlorite with variable Mg/Fe chemistry. Additionally the results show background spectral characteristics that mimic the magnetite distribution.

Jan 1, 2004

By Balint F

The Izok massive sulphide deposits are located in the Northwest Territories of the remote western Canadian Arctic. Together they represent one of the highest grade undeveloped zinc-copper resources in North America. Metall Mining Corporation is presently engaged in a feasibility study on developing the Izok property as well as actively exploring for additional reserves. The Izok deposits are Archean-aged, volcanogenic massive sulphide (VMS) bodies hosted within and near the top of a thick sequence of predominantly felsic pyroclastic rocks. The hangingwall package includes additional felsic volcanoclastics, dacitic and basaltic flows, thin sulphide-rich iron formations, and turbiditic sediments. The felsic volcanics are intruded by syn- to late-hydrothermal dacitic dykes and sills and post-hydrothermal gabbroic dykes and sills. Both intrusives are interpreted to be volcanic feeders to overlying flows. All lithologies are cut by much later irregular granitic pegmatite dykes and regionally metamorphosed to pyroxene homfels grade. The deposits occur within a large kilometre-scale soda-depleted alteration zone. The immediate footwall and hangingwall rocks to the deposits are characterised by zones of muscovite-biotite (with or without sillimanite), lesser chlorite-biotite-cordierite (with or without anthophyllite), and locally intense silicificified and albitised zones. All lithologies have been affected by a later calcic metasomatic alteration. As currently defined, the Izok Zn-Cu-Pb-Ag deposits comprise a cluster of four complexly-zoned composite lenses: the Northwest, North, Central, and newly discovered Inukshuk deposits. The first three deposits are amenable to open pit mining while development of the Inukshuk deposit will require underground methods. The combined mineral inventory of the Northwest, North, Central and Inukshuk deposits at present totals 15.6 million tonnes with a grade of 2.4 per cent Cu, 13.8 per cent Zn, 1.4 per cent Pb, and 74.6 g/t Ag.

Jan 1, 1993

ALTHOUGH the mineral Stannite (Cu2S, FeS, SnS2 , also known as "bell 'metal" ore, tin pyrites, etc.) is found in various parts of the world, in only three iocalities has development proved it to exist in sufficient quantity to warrant the erection of treatment plants. Two of those mines are in New South Wales and one is an Tasmania. The writer will deal with the latter-the Conah mine, Zeehan, Tasmania, it being the most important and extensive occurrence so far worked. The Conah mine was first worked by a Tasmanian company for silver-Iead, and was fairly remunerative until the zone of secondary enrichment was passed through, when the lodes became too poor for further exploitation. During the time that the line was thus operated the stannite lode was discovered. It occurs in a graphitic slate, which, in common with the slates and spilites of the Zeehan field, is probably underlain by the stanniferous granite which outcrops two miles to the west. The Conah stannite lode is older than the galena lodes of the district, being faulted by one of the latter. Near the surface the lode was very rich.Shipments were sent out assaying 150 oz. of silver per ton, 20% copper, and 18% tin. An .apparently homogeneous sample of stannite, analyzed by the writer for the Tasmanian Geological survey, gave the following results:

Jan 1, 1915

The Palaeozoic succession of Victoria contains one of the world's major gold provinces with a total production of 2500 tonnes of gold. Larger deposits, including Bendigo (over 800 tonnes Au), are related to Ordovician slates and greywackes, but a wide range of metamorphosed sedimentary and igneous rock types are host to significant gold deposits. Most, if not all, deposits demonstrate structural control, although the controlling structural features are variable between deposits: a majority of deposits comprise quartz veins. It is suggested here that a major factor in making Victoria such a gold-rich province might be a particularly high geothermal gradient in central Victoria during the Tabberabberan orogeny (360-380 my). This generated auriferous metamorphic fluids from underlying successions (?Cambrian) which migrated upwards along active structural pathways. One cause of gold deposition appears to have been fluid reduction by carbon, but other methods are suspected. This model is considerably simpler than the plethora of syngenetic, granite magmatic and lamprophyre-related models that have been proposed recently, but is in basic agreement with Cox et al. (1983). Exploration models for similar gold deposits both within Victoria and elsewhere should take account of the negligible evidence for a major syngenetic contribution to Victorian gold production, and the lack of any clear genetic relationship to particular igneous rock types. A real opportunity exists for new deposit types not identified by the early prospectors.

Jan 1, 1991

By Nemcik JA, Gale W. J

The magnitude and orientation of the in situ stressfield has been determined as a key factor in controlling the stability of openings for both coal mine development and extraction. Monitoring of roadway and pillar behaviour in conjunction with numerical analysis has identified specific stress control measures that have been successfully applied to improve productivity in underground coal mining operations. The influence of the major horizontal stressfield on the stability of openings has been identified at a wide range of sites including mines in Australia, Britain, the USA, New Zealand and Japan. Stress mapping, stress measurement and stress monitoring techniques have been applied to define the in situ stress regime and, together with the correlation of measurements of rock deformation and rock reinforcement behaviour, has enabled appropriate stress control measures to be developed. Stress control measures for development headings have required the selection of roadway orientation, roadway sequencing, reinforcement density and pillar size. The monitoring of behaviour at a range of trial sites has confirmed significant improvements in development stability. Stress control measures for longwall extraction have required rational selection of longwall orientation and extraction direction. Where a mine layout design incorporating the optimum longwall layout design has not been possible, the use of sacrificial roadways has been successfully applied to protect key roadways from stress concentration effects. Comprehensive in situ

Jan 1, 1992

Minerals and Metals Group (MMG) Century mine (Century) is a large open-cut mine in northwest Queensland approximately 2.5 km long, 1.5 km wide and 240 m deep, with an ultimate pit depth of 320 m. In 2009, the mine experienced three failures which began as small failures, and progressively developed into significant multi-batter failures. The incidents were managed by a combination of analysis, redesign and practical management to achieve positive outcomes for the mine. On the south wall of the mine, a series of batter-scale wedge failures occurred in December 2007. Analysis of structure orientations and design changes aimed to minimise the risk of failure extending over multiple batters, while accepting a risk of further small-scale failures. Design changes were constrained by a culturally sensitive area (CSA) located south of the wall. As mining progressed, shallow wedge failures developed over multiple batters and cracks were observed 60m back from the pit crest, indicating that a large-scale wedge failure was developing. Movement increased in January 2009 as a result of significant rainfall. After considering several design options, the area was stabilised by a cut-back of the wall. Two multi-batter failures also occurred on the north wall as mining progressed through a structurally complex area. Both north wall failures began as small failures that progressively developed, and required a redesign of the wall below as well as practical management of safety aspects. The complex structural geology was difficult to predict ahead of mining, and required geotechnical input into design changes as mining progressed. All three failures potentially had significant impact for ore recovery, and were managed by a combination of analysis, redesign and operational management have resulted to achieve positive outcomes in a challenging mining environment.

May 1, 2010

By D Alexander

For nearly 100 years, the flotation plant metallurgist has often wondered what is happening æbeneath the frothÆ. To assist in unravelling this mystery, new technology has been developed as part of the Australian Mineral Industries Research Association (AMIRA) P9 project, to measure gas dispersion characteristics (such as gas hold-up, superficial gas velocity and bubble size) in industrial flotation cells. These measurements have been conducted in a large number of cells of different types and sizes by researchers from the Julius Kruttschnitt Mineral Research Centre (JKMRC) and JKTech. A large database has been developed and the contents of this database are described in this paper. Typical cell characterisation measurements show a wide spread in values, even in the same cell types and sizes performing similar duties. In conventional flotation cells, the typical gas hold-up values range from 3 - 20 per cent, bubble sizes range between 1 and 2 mm, and superficial gas velocity ranges from 1 to 2.5 cm/s. The ranges of cell characterisation measurements given in this paper will enable plant personnel to compare their operation to other similar types of operations from around Australia and the rest of the world, giving opportunities for further improvement to flotation plant operations.

Jan 1, 2005

By N Kusuma

Recoverable copper and gold estimates for resource models and ore control routing decisions at Batu Hijau were initially based on flotation testwork from several commercial laboratories. Due to the greater number of copper and gold assay grade available, regression relationships were developed between assay grades and flotation recoveries. Other recovery controlling variables such as oxidation and lithology were included to improve the regression models. With additional drilling, more flotation work was carried out and the regression models were revised to include the new flotation data, also alteration classification and in situ pH. The regression models were replaced in favour of spatially derived models for ore control and short range mine planning. To harness local variability in the block model, blast hole flotation testing is carried out in unison with routine grade assaying. Recovery data are processed (kriged) simultaneously with grade assay data prior to ore polygon delineation. Short range mine planning utilises this model in conjunction with a spatial recovery model derived from drill core flotation data. Long range mine planning utilises the æhybridÆ recovery model whereby the globally robust regression recovery models are overprinted by a spatial (kriged) recovery estimate where flotation data density is adequate (Phase II reserve).

Jan 1, 2002

The Perth Mint receives gold and silver from various sources for evaluation and refining. The metals are received in many forms and vary widely in assay. Refining is carried out using the Miller Process and the and the resulting market quality bullion is sold in a range of weights and alloys to suit the international bullion market and public demand. INTRODUCTION The Perth Mint was established in the late nineties as a branch of the Royal Mint, London, to refine the gold from the newly established gold- fields in Western Australia. The branch was opened for business in June, 1899. After refining, the bulk of the gold was used in the manufacture of sovereigns and half-sovereigns. Nowadays, although most of the gold received comes from the W.A. goldfields, some gold is deposited by producers in other states and in Papua-New Guinea, as well as scrap and trade wastes from manufacturing jewellers and old jewellery from the general public. Silver is deposited in the form of old silverware, recoveries from-photographic processes etc. Gold or silver may be lodged at the Mint in person, through a bank or other agency or by registered post. Telegraphic advice is usually given when gold is sent by the latter, so that insurance may be effected.

Jan 1, 1982

AustraliaÆs record-breaking drought, efforts towards environmental best practice and the current commodities boom is demanding water use and reuse as never before. Mining practices, processing, the remote communities and support industries require vast amounts of specific quality water. Sustainability of water use has been a key factor in mine development, expansion of existing operations and increasing profitability of processes involving water. Developments in water treatment technology have enabled the use of a range of processes to produce this water reliably at ever decreasing costs. This increasing acceptance of new technologies has seen seawater desalination, recycling of plant wastewater streams, municipal wastewater reuse and others to become commonplace. Processes including seawater and groundwater reverse osmosis (RO), low pH RO, thermal desalination, high rate clarification, brine water treatment, ion exchange and other advanced treatment technologies are now used as part of mining operations. This paper surveys the trends in water treatment for the mining industry both in Australia and internationally with a review of technologies and case studies of operating plants. The key technologies are explained with an emphasis on the specific requirements for mining operations û unusual raw water, process and operations limitations, environmental concerns, as well as harsh climate. Case study information from several mining operations is included.

Jan 1, 2006

By Sneddon NW

Aberdare North Colliery is situated on the eastern boundary of the City of Cessnock in the Hunter Valley, New South Wales. Although the area is now noted for its wines and vineyards, the district has a long history based on coal mining. The richest coal seam in the Cessnock district is the Greta Seam, a low ash, high volatile steaming or gas making coal. The seam, up to 10 metres thick, extends over a large area surrounding the city of Cessnock and neighbouring townships such as Bellbird, Aber- dare, Kearsley, Neath, Ellalong, Kurri Kurri and Stanford Merthyr. The Aberdare Colliery, leases, which extend under Aberdare and Cessnock townships, were first worked in 1905 and continued developing pillar panels until the mine closed on 11 Nov- ember, 1960. Coal mining to this time consisted mainly of developing pillars to the 2.4 metre parting and, in some areas, dropping the top coal to the 6 metre parting, thus leaving the pillars intact, the top 1.8 metr-es of coal be- ing left untouched due to the high sulphur content. Aberdare North Colliery was opened in 1956 in order to recover and extract the pillar coal and tops left standing for over 40 years. During the pillar extraction phase the occurr

Jan 1, 1981

The need to solve the problems associated with spontaneous combustion, system of ventil- ation and methane drainage in gassy coal mines has brought about the development of mining and degassing methods which has made possible up to 80% gas recovery in retreating longwalls. Beneficial results also were obtained mostly in the double or multiple-entry systems, but for single-entry systems and for a seam thickness exceeding 3 m, gas recovery rate is still very low. With some single-heading systems, such as those where a return roadway is not maintained in the goaf behind the face line, a new methane drainage technology is practiced. Attempts were made to extract methane from roof holes drilled from offsets in the ribside of the longwall block. The inclinations and lengths of the boreholes were planned and designed on the basis of the geological and mining condit- ions encountered at the time and every second hole was terminated precisely at the point where the previous hole intersected the immed- iate roof goaf area above the face. There are mathematical relations approp- riate to the design of the above drainage systems to give optimum methane recovery under the given conditions. Some examples of drainage have reached 87% recovery and have attained 94% CH4 purity.

Jan 1, 1982

This paper provides a brief fundamental insight regarding the fabric media concept for liquor filtration. The subject matter will be of interest to metallurgists and engineers with professional responsibility for world class design of solid liquid separation processes and efficient lowest cost operation of existing mineral process plant. Avocet Mining commissioned the worldÆs first mineral liquor clarification process incorporating a fabric media liquor filter at their Lanut gold mine in Sulawesi, in 2004 with design consulting provided by the Australian company SLS Technology Pty Ltd. Development of the technology continues with applied research focused on selecting textile parameters to apply filtration to a wider range of particle and contaminant types, higher solids concentrations, and different process liquors. Liquor filtration with the Fabric Media technology offers an array of attractive benefits. For Avocet Mining, filtration of pregnant liquor directly from the heap leach pad has enabled removal of the sediment pond and sand filters from the traditional process flow sheet, thus providing significant cost and installation time savings. Avocet Mining has recently expressed confidence in the technology indicating selection preference of the technology for the expansion at Lanut and for a new project. The application design window for the Fabric Media concept is extremely flexible with the technology now successfully applied to many different liquor chemistries and application objectives around the world. Potential cost savings for solid liquid separation process plant, such as counter current decantation circuits, clarifier vessels and thickener tanks can be calculated from laboratory measurements or pilot plant demonstrations.

Jan 1, 2008

Every text book for blasting in Japan says that Hauser's law can be applied for practice. But recently it came true that there was no historical record about him and no actual datum of his own or other's to testify. According to his theory, the funnel ratio N = r/W in crater test is inversely proportional to the rock strength and proportional to the explosive amount: where r is the radius of crater and W is the burden. But experiment showed the opposite result, and revealed new information. Two kinds of experiment, crater test and boulder blasting of mortar, were carried out to investigate the effects of rock properties on blasting. The material used for test 1 and test 2 was a mortar block (60cm)3 cube, 4 vertical faces of which were used for crater test. The results from Test 1 and test 2 were summarized as follows. The funnel ratio ranges between 2.5 to 4.5 in proportion to rock strength and burden. The standard ratio of 1, reported by Hauser, was not observed in any instances. It was also noted that the funnel ratio is independent of the explosive amount. The material used for boulder blasting, test 3, was a mortar block (40cm)3 cube, in the middle of which was located a vertical borehole for the explosive charge. The results of test 3 were as follows. The necessary explosive amount for boulder blasting is in inverse proportion to the mortar strength. Fragmentation and throw are proportional to the mortar strength.

Jan 1, 1990

By Mendeckl A. J

Anglo American Corporation has always viewed technological development as vital and as such has placed research and the implementation of new technological practices high on its priority list. Support is given to a number of research institutes but a significant degree of reliance is placed on in-house research carried out at individual companies and at the Group's main laboratory complexes. The Corporation's interests are diverse with advanced practices and innovative technology ranging from new battery technology with wide application to deep level shaft technology with very specific application. In this paper, we aim to concentrate on a particular system developed primarily for use in seismically active deep mines. The system has proved to have far wider application and has the potential to be further enhanced to meet the needs of users across a broad range within the industry and even beyond. As the nature of this conference is to inform delegates of advanced mining practices, we should simply mention that we could have talked on subjects relating to the advances made in deep level winding technology including winder drive and brake control to alleviate dynamic rope loads, shaft steel design for high pay load high speed winding and shaft safety systems such as slack rope devices and moving lip loading facilities to cater for rope stretch. Other areas of interest relating to refrigeration using ice technology or non-explosive rock cutting using diamond wire or saw technology could also have been of interest. As the South African gold mines become deeper and the problems associated with depth become more acute, answers had to be found and systems developed to cope with very high rock stress and the related seismicity. The fundamental understanding of the behaviour of the rock mass has always been important but became critical on our mines to ensure the safe extraction of the orebody. Basic research into and the application of physics, applied mathematics, seismology, rock mechanics, electronics and computer technology have helped us to develop the Integrated Seismic System - Integrated because of the system's abilty to monitor seismic and non-seismic sensors simultaneously and because it encompasses data acquisition, processing and interpretation into one system. The system which is in use at all our gold mines has found application not only in South Africa but also in such locations as Australia, Chile, Canada, Europe and Japan. A highly motivated team of scientists under the leadership of Aleksander Mendecki developed the majority of the hardware and software needed for the system. In essence, the system allows us real time monitoring of energy release and stress transfer data that with the aid of modern computers is turned into useful information. The information so obtained has allowed us to improve our mine and extraction designs to minimise the inherent hazards. The system has proved to be an extremely useful management tool as substantiated by the demand for the product. The paper is intended to convey to the reader the technical concepts and the presentation is intended to demonstrate the usefulness of the system.

Jan 1, 1995

By A M. van Niekerk, W Mey

Coal mining has an impact on the water management of the water scarce Upper Olifants River Catchment. A prefeasibility study was carried out by Anglo Coal and Ingwe Collieries Limited to establish the water supply and demand in the catchment. A geohydrological model was used for the coalfields to determine the stored water and excess water available. Two distinct collective and treatment systems were proposed for the Witbank and Middelburg municipalities to treat excess water from the Anglo Coal and Ingwe Collieries Limited. The Emalahleni Water Reclamation Project for Witbank was initiated first. Water management and treatment experience gained at Anglo Coal was the cornerstone to develop the collection, treatment and distribution system. A full enquiry was issued to Keyplan, Veolia, Bateman Africa and IST Technik to construct, commission, operate and maintain a 20 ML/day desalination plant to treat acidic, saline mine waters to a South African National Standard (SANS) 0241 Class 0 potable water. After the technical and financial adjudication, Keyplan were awarded the contract. An integrated regulatory process was adopted through consultation with all the relevant regional and head office staff of the Department of Minerals and Energy, Department of Water Affairs and Forestry and the Mpumalanga Department of Land Affairs via an authorityÆs steering committee. A rock engineering evaluation was done to select both the plant and waste disposal sites as all possible sites are undermined. Various contracts are required with the individual mines for water supply, the Emalahleni Local Municipality for the delivery of potable water and for the disposal of wastes.

Jan 1, 2006

By Burman B. C

This paper describes studies into two particular aspects of the Lochiel deposit which formed part of feasibility level geot2chnical and hydrogeological investigations for proposed open cut mine development. The two aspects were depressurisation of thick beds of silt located through the profile and the determination of characteristics and origins of soil structure and their effect on pit stability. The studies were very detailed and multi disciplinary and highlight the integration of geology, geotechnics, hydrogeology and mining that is required for mine development studies. It is considered that as more marginal deposits are developed throughout the world the demands for efficient economic mining together with in- creasing scales of operation will require simi- lar types of studies. As such the studies pre- sented herein are likely to be a forerunner to a,emerging trend for development of open pit mines in difficult ground and water conditions.

Jan 1, 1986

By J Cook, S Pike, D Pridmore

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The application of high-resolution seismic reflection to map structure and/or mineralisation in hard rock environments has progressed significantly in the last decade. Improvements in equipment, field practice, processing and understanding has seen the seismic reflection technique emerge as a cost-effective tool for high-resolution three-dimensional structural and lithology mapping to depths far greater and with superior accuracy than other more conventional geophysical techniques.This paper outlines results and preliminary interpretation of 2D and 3D seismic reflection surveys aimed at defining fault zones and locations for quartz load development in favourable host lithologies at the Cracow low-sulfidation epithermal gold system in Queensland, Australia.As this is possibly the first time that high-resolution seismic reflection data has been used to define the structurally-controlled location of low-sulfidation epithermal gold mineralisation, an important aspect of this work was the derisking or due diligence steps taken prior to commissioning the full 3D surveys at each site. This included full wave sonic logging, vertical seismic profiling and trial 2D lines. Interpretation of the 2D profiles and the drilling of interpreted structure provided the confidence to proceed with the full 3D survey.The advantage of collecting 3D data extends beyond ensuring that the received reflections are located correctly in 3D space. The final 3D data cube can potentially map the entire fault network, thus highlighting flexures and changes in orientation of the structures both vertically and along strike, which is an important aspect in the deposition of gold and for direct targeting.CITATION:Smith, R, Cook, J, Pike, S and Pridmore, D, 2015. Application of high-resolution seismic reflection surveys to exploration for blind vein systems at the Cracow low-sulfidation epithermal field, in Proceedings PACRIM 2015 Congress, pp 77–84 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By M N. Ingham

X-ray fluorescence (XRF) spectrometry has always been considered to be a comparative method of analysis. Reference materials are required to calibrate the analytical system. This paper describes the use of a set of æsyntheticÆ oxide standards, made from commercially available high purity compounds, to calibrate a spectrometer for 21 major and minor oxides. The spectrometer software uses simple methods of background correction, and a fundamental parameter method of matrix correction. Sample preparation is by fusion in 66 per cent lithium tetraborate, 34 per cent lithium metaborate. The use of synthetic standards, made from traceable compounds, brings XRF significantly closer to being a primary rather than a comparative method. Reference materials were used to validate the method described and examples of accuracy for major constituents are given using ores and other minerals. This method has successfully been used to analyse a wide variety of minerals and ores, as validation data shows. A titanium process example clearly shows the benefits of highest accuracy analysis.

Jan 1, 2008

By K Bojarska

Examination of wastes aimed at evaluation of their usefulness for utilisation needs applying modern chemical testing methods. The XRD-XRF-ICP-GC/MS set of test methods constitutes an integrated testing system enabling ecochemical examination of wastes. As far as the problem of time-consuming operations is concerned, the offered system fits in a market-oriented field of activity of accredited chemical laboratories. Within a reasonable period of time, it allows to obtain information about mineralogical and chemical properties of wastes. It provides full range of information beginning from mineral composition (XRD) through chemical composition including the number of elements and organic compounds (XRF-ICP-GC/MS) up to the contents relating to the amounts of ingredients, both organic and inorganic in the leaching tests (ICP-GC/MS). The XRD-XRF-ICP-GC/MS testing system proves to be of particular importance in obtaining reliable results enabling to perform precise assessment (from ecochemical point of view) of wastes to evaluate their usefulness for utilisation in building materials, in civil engineering and reclamation works.

Jan 1, 2003