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By D J. Clark, R F. Wright, M D. Goodz

The A1 Gold Mine is a Devonian-age narrow vein high-grade gold deposit located 115 km east of Melbourne. The mine operated almost continuously from 1861 to 1992 producing 442 334 ounces of gold (13.8 t) from 530 436 tonnes from primary gold ore tonnes processed at an average recovered grade of 25.9 g/t Au. The A1 dyke was attributed with a yield exceeding 620 000 ounces (19.3 t) of gold (including gold in alluvial and tailings deposits), and was renowned as one of VictoriaÆs premier mines paying considerable dividends. The orebody was principally in a diorite dyke bulge 150 m long, 45 m wide and 700 m deep and was mined via two vertical shafts. The mine site was closed in 1992 and the site was rehabilitated in 1999. In 2008 - 2009, a diamond drilling program identified various extensions to the host dyke lithology and to gold-bearing quartz vein filled fault zones over a 700 m strike length. The outcome of this study was the establishment of a mine geology corridor four times longer in strike length than the original 1970s model. This opens A1 dyke hosted deposit style to exploration outside the historical dyke bulge and provides exploration opportunity for all similar deposits. Construction of the first 3D geological model has developed new insights on the host rock diorite dyke system and identified various extensions to both host stratigraphy and to gold-bearing mineralised structures. Coarse visible gold in quartz vein mineralisation (>30 g/t Au) and medium-grade stockwork mineralisation (8 - 15 g/t Au) has been intersected within 100 m of the surface and up to 300 m along strike of the nearest historical underground workings. At depth it appears that the mineralisation is continuous with the main dyke body with consideration of minor rotation in the strike orientation and limited reverse thrust faulting showing maximum displacement of 10 - 20 m. Along the A1 mine corridor, between two and five parallel dykes are observed at different drill sections. The gold mineralisation is hosted mainly within the dyke rocks, but where the sedimentary rocks are intensely silicified or are xenolith rafts, the gold mineralisation continues across these sedimentary rock blocks. There has been inference to the role of silicified sedimentary rocks as a second ore host and a bounding material for inflections in fault and vein orientations. In the central 150 m long A1 mine dyke bulge, the extremities are demarcated by four to five parallel dyke fingers (referred to as apophyses) going both north and south. These apophyses are clearly observed both vertically and horizontally between levels No 4 and No 9. The dyke fingers entrap sedimentary rock xenoliths and collectively form the A1 dyke æcorridorÆ, which is quite uniform in overall width from the easternmost contact (footwall) to the westernmost contact (hanging wall). Dyke fingers were assumed to coalesce at depth into a single dyke, but recent drilling shows this feature to repeat in several positions with depth and along strike. Key observations are the relationship between gold grade and fracture density, alteration, sulfidation, host rock morphology û relation of contact shape and fault zones. These relationships allow for the classification of prospectivity indicators and geology as a guide to potential extensions of mineralised zones. Mining geology is contributing to the whole-of-mine life planning and development where decline path, stockpile and infrastructure positions are controlled by geology.

Jan 1, 2009

By G Anderson, M Mativenga, C Stanton, M Larson

Arrium’s magnetite concentrator has recently completed a modification program to improve the process that has been in operation in Whyalla, South Australia for the previous seven years. The magnetite concentrate is pumped via pipeline to the coast and serves as pellet plant feed, eventually being turned into steel in the Whyalla blast furnace. With the addition of a new 3MW IsaMill at the concentrator, the plant has seen increased production from a reduced feed grade, enabling Arrium to treat ores previously stockpiled as waste. This paper will focus on the design work and commissioning of the fine grinding circuit along with the year of optimisation that followed, taking the IsaMill up to 350+ tph of throughput.CITATION:Larson, M, Anderson, G, Mativenga, M and Stanton, C, 2015. The Arrium IsaMill from design through commissioning and optimisation, in Proceedings MetPlant 2015, pp 110–119 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

The upper amphibolite-grade mctasediments of thc rinaroo area, North Queensland, form part of a regional aurcole to the large Tinaroo Batholith and are the stratigraphic equivalents of the Hodgkinson Formation of gencrally low metamorphic grade. There is no evidence of any lithological unconformity.The higher grade metasediments have a more complex deformation history than is typical for thc surrounding region and this may bc due to one or a combination of two factors; an additional strain componcnt associated wilh the intrusion of Ihe Tinaroo Batholith, or a more marked finite strain response to the overall regional stress field within hotter. more ductile rocks.Four deformational events can be characterized within Ihc Tinaroo Area. Close to Ihe Tinaroo Batholith D1 and D2, arc so strongly developed that they disrupl the continuily of Ihe original Iithological layering. In the aureole region, D1 is strongly overprinted and its original fabric intensity is obscured, but both D2 and D3 display a mappable decrease in intensity away from the granite margin. These three deformations occurred during Carboniferous or early Permian time. D4 is later and only patchily developed.The broad, moderate pressure metamorphic aureole surrounding the Tinaroo Batholith is a typical of the CairnsCooktown group of Permo-Carboniferous granitoids. which usually develop narrow, lower pressure contact aureoles. Two periods of metamorphism are distinguishable. The first reached peak temperatures somewhat greater than 520°C, the second temperatures around 620-630° C immediately adjacent to the granite contact.Several cale-silicate lenses containing scattered scheelite mineralization occur within the area. Scheelite appears to have crystallized at the same time as the cale-silicate minerals, its appearance coinciding with the intrusion of the Tinaroo Batholith. Unlike many "skarn-type" scheelite deposits, the scheelite-bearing cale-silicates are Fe-poor, with no positive correlation between total Fe and W.

Jan 1, 1982

Observed mineral assemblages in the Mt. Lyell copper deposit can be correlated with phase equilibrium investigations in the systems Cu-Fe-S and Fe-Zn-S. The trend of crystallization (or paragenetic sequence) of the ores is reflected in a progressive increase in the Cu: Fe and metal: sulphur ratios of the assemblages. This trend agrees with the regional zoning of the district. Tentative relationships between the paragenetic sequence, sulphur vapour pressure, and temperature are presented graphically. The absence of a suitable geological thermometer prevents precise elucidation of the range of temperatures and pressures which existed during crystallization.INTRODUCTIONRecent phase equilibrium investigations of metal-sulphur systems at the Geophysical Laboratory, Washington, D.C. provide valuable information on the stability relations of a number of important sulphide minerals. This data, when applied to natural ore deposits, may be expected to clarify two special problems which confront the ore petrologist seeking to interpret observed data in terms of a particular physical and chemical environment of ore deposition. These two problems are the sequence of formation of sulphide minerals (commonly designated the paragenetic sequence) and an elucidation of the range of temperatures and pressures which existed during crystallization. The object of this paper is to make such an interpretation of the copper mineralization of the Mt. Lyell district, Queenstown, Tasmania.The following abbreviations are used in this paper:py = pyrite, cp = chalcopyrite, en = cubanite, bn = bornite,cc = chalcocite, cv = covellite, dg = digenite, id = idaite,po = pyrrhotite, v = sulphur vapour.GEOLOGICAL SETTING AND MINERALIZATIONThe general geology of the Mt. Lyell district is well known through the recent work of Wade and Solomon (1958). The host rocks are a series of quartz-chlorite-seri-...

Jan 1, 1963

Modelling Channel Scale Flow in Heap Leaching Using Smooth Particle Hydrodynamics (SPH)

Sep 13, 2010

This backgrounds the methods, and technical terminology, of digital image processing techniques used to write out remote sensing imagery.

Jan 1, 1983

A wide-ranging base of jig data was collected from various types of commercial jigs in 9 coal preparation plants in China, and a complete data analysis was made. It was found that the sharpness ofseparation was very variable, which demonstrates the complex interplay of the many factors which influence jig performance. Tests showed that there exist optimum frequency ranges in each compartment of a jig. Stepwise regression analysis indicated that the sharpness of separation is most sensitive to the intake fraction ofthe air cycle, the frequency, and the feed rate. By means of non-linear curve fitting techniques and statistical analysis, several mathematical models were developed to describe both partition curve and the jig performance, for simulation purposes.

Jan 1, 1986

The papers in this section of the conference and indeed the conference as a whole will rightly focus on the recent û the state of play around the Pacific Rim. However, to set the scene I propose to take a longer-term perspective. In so doing I wish to illustrate and emphasise that change is normal and natural û to paraphrase Bob DylanÆs 1963 classic, æThe times they are (always) a-changinÆ Æ. The challenge is how to cope with such change, in an industry, a corporate and a personal sense. A further challenge for geologists, both exploration and mine-based, and indeed for anyone, is to understand where they fit in the broader picture. For several reasons it is appropriate first to look briefly at the minerals industry in the Pacific Rim around a century ago. It was here in Adelaide in April 1893 that the first general meeting of the Australasian Institute of Mining Engineers (or The Australasian Institute of Mining and Metallurgy as it later became) took place and where the Centenary Meeting was held in 1993. The late 1800s and early 1900s was a period of extraordinary change in the minerals industry regionally and worldwide. The industry benefited from the economies of scale provided by improved mechanisation. It further benefited from the introduction of technically qualified professionals, such as chemists, metallurgists and mining engineers, although the usefulness of geologists had yet to be recognised commercially. With the rise of such professionals, technical societies formed and flourished. At the same time international financial markets and trade were expanding, a gold standard was widely supported and the financing of mining ventures was well established. Mining was an international business and its people travelled widely. As a consequence of the better-educated mining professional, the ready exchange of knowledge and the availability of finance, new processing techniques such as pyritic smelting, the cyanide process and flotation were developed. These, together with much improved materials handling in the mining and processing phases, dramatically changed the economics of the minerals industry.

Jan 1, 2004

By N A. Sikwa, L M. van Niekerk, G N. Ndlovu

In June 2012, Lucara Diamond Corporation officially commissioned its Karowe Diamond Mine in Letlhakane, Botswana. The processing plant circuit incorporates variable speed autogeneous milling, a first for African diamond processing - only previously practiced in Russia. The paper discusses the basis for the selection of milling against the more traditional circuits incorporating crushing and scrubbing. It covers early commissioning challenges of operating a mill in an æalien environmentÆ with no immediate reference plant to look up to for bench-marking.The paper describes how these challenges were overcome and learnings quickly incorporated into the mill operating philosophy for maximum diamond liberation and minimum product damage. The plant was commissioned in three months and by August 2012 the production ramp up had reached name-plate capacity. The feed to the mill has varied from highly weathered material to extremely hard kimberlite and the operating philosophy had to be optimised for the full range of ore types. While more work is required to stretch the mill operating envelope coupled with other circuit additions to improve liberation of fine diamonds at minimum capital expenditure, the mill has, to date, performed to its billing.CITATION:van Niekerk, L M, Ndlovu, G N and Sikwa, N A, 2013. Commissioning and operating an autogeneous mill at Karowe Diamond Mine, in Proceedings MetPlant 2013 , pp 215-228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Cotton R. E, Cox R

Digger Rocks is one of several nickel-bearing sulphide deposits localised within komaLiitic volcanics of the Forrestania Greenstone Bell within the Archaean YiIgam Block of Western Australia. Exploration and evaluation to April 1990 have delineated a resource, at a nominal cut-off grade of 0.5 per cent Ni, of 1.9 Mt at 1.1 per cent Ni within a lensoid sulphide body which strikes NW, dips 50°SW, and occurs at a depth of 30 - 110 m below surface. There has been no production from any of the Forrestania nickel deposits to-date. The deposit, comprising both disseminated and massive sulphides, has maximum dimensions of 400 m strike, 115 m vertically and 90 m true width. Generally the massive sulphides occur at the base of the disseminated sulphides, on or close to the base of the Digger Rocks dunite. The two main massive sulphide lenses have maximum dimensions of 120 m strike, 75 m vertically and 16 m true width (northern lens) and 60 m strike, 25 m vertically and 4 m true width (southern lens). The average grades of the massive and disseminated sulphides are 5.9 per cent i and 1.2 per cent i respectively. The massive sulphides generally have sharp hangingwall and fOOlwall contacts and display strong internal grade anisolropy.The massive sulphides are mainly within the supergene zone and consist of violarite, pyrite and marcasite. The disseminated sulphides are mainly within the primary zone and consist of pentlandite, pyrrholite, pyrite and minor chalcopyrite. Alteration zones, up to six in number, are complex in detail. The sulphides are capped by an average of 30 m of sub-economic, leached, siliceous, oxidised material.A genetic model for the deposit is described which places Digger Rocks in Category 2 (sulphides in large layered dunite bodies) of the latest classification of komatiitic nickel sulphide deposits in the Yilgam Block of Western Australia by Hill and Gole (1990).

Jan 1, 1992

Measurement of densities, susceptibilities, permanent magnetization, and calculation of demagnetization factors has allowed computer modelling of gravity and magnetic data over the Middleback Range iron formations of South Australia. As well as providing structural information, the study emphasizes the effects of weathering on the interpretation of magnetic data.

Jan 1, 1975

Owing to the 'creeps' and consequent movements in the mines, followed by the recent fire in the southern workings, the whole of the orebody above the 800 ft. level is now very much crushed and broken. The same applies to the hanging wall or overwall coutrny, which has subsided towards the workings, so that for some years past all development work within the lode has had to be carried out with extreme care.The continual but slow subsidence of the overburden into the stopes necessitates a periodical renewal of all gangways in the lode, and, as the subsidence amounts to as much as 60 ft. in places, these new gangways must necessarily pass through the mullock-filling of old stopes in addition to broken ore. They at times pass into the broken ground of the hanging-wall for some distance, where the orebody has widened underneath by the original folding and puckering.

Jan 1, 1932

By A B. Christie

Known epithermal deposits in the Coromandel region belong to the low-sulphidation type, represented by three subtypes: (1) andesite-hosted epithermal Au-Ag, (2) rhyolite-hosted epithermal Au-Ag, and (3) andesite-hosted polymetallic veins. Paleo-depths for a range ofdeposits are estimated using various features including: paleo-surface indicators (e.g. sinters), hydrostatic pressures estimated from homogenisation temperature measurements on fluid inclusions, and alteration mineralogy. Paleo-depth estimates to the base of the ore zone for the rhyolite-hosted Coromandel deposits are in the range 200 to 500 m. Andesite-hosted Au-Ag deposits have more variable paleo-depths, and are deeper (up to 950 m) in those deposits with base metals at depth. The majority of Coromandel Au-Ag deposits have limited depth extents (<200 m) of economic grade mineralisation, although Waihi and Karangahake are notable exceptions with depth extents of 575 m and 700 m respectively. Limited depth extents of economic ore are a feature of epithermal systems worldwide and are commonly attributed to gold deposition from boiling fluids. Under hydrostatic conditions in epithermal/geothermal systems, boiling in an up-flowing hydrothermal fluid is controlled by the boiling point for depth (BPD) curve. From fluid inclusion studies of many low-sulphidation epithermal systems, deposition of electrum in economic concentrations appears to be confined to a temperature window of 260 to 180¦C. This means that for dilute, gas-poor fluids that follow the BPD curve, gold deposition is limited to a vertical depth zone of about 400 m, with its upper boundary at about 100 m below the ground surface. The greater depth extent at Waihi and Karangahake, can be explained by mixing of/a deep, hot (300¦C) fluid with cooler (c. 200¦C) heated ground waters. This has the effect of lowering the 260¦C isotherm by up to 300 m, thereby increasing the depth range of economic grade gold deposition within the 260 to 180¦Cwindow of electrum deposition.

Jan 1, 2000

By J J. Batchelor, J B. Metson

Titanium (ilmenite) concentrate was extracted from a New Zealandilmeno-magnetite deposit. Tailings from the existing processing line at the Waikato North Head ironsand concentration plant were used as a raw material feed. The titanium bearing mineral extracted was defined as intergrowths of ilmenite and hematite in the size range below 150 um. The Owen-Honda equation was used to determine the conditions forilmenite/hematite magnetic separation. Three distinct regions of magnetic field strength for the mineral separation have been defined. Theoretical estimates from this calculation have been confirmed experimentally. Ilmenite concentrate was obtained using medium field magnetic andelectrostatic separation. The final material contains 40.6 - 42 per cent TiO2 and 39.1 - 39.8 per cent Fe (total). The actual yield from extraction was about seven per cent of the Zircon, leucoxene and monazite were found as byproducts of thetitanium concentration process. Preliminary experiments have shown the viability of industrial zircon benefication.

Jan 1, 2000

By Ruxton B. P, Rhodes J. M

Two Rb-Sr ages are discernible in data concerning the leucocratic granite which is the youngest pre-sedimentation phase of the crystalline basement complex at Rum Jungle, Northern Territory, Australia. Whole-rockdata suggest that intrusion of this unit took place at about 2400 my ago, with a probable initial ratio around o·707; whole rock-potassium feldspar tie-lines indicate redistribution of strontium at about 1800 my ago. The former age correlates with other measurements on rocks which form basement to the mantling Pine Creek Geosyncline; the latter correlates also with isotopic evidence for regional metamorphism and emplacement of some younger intrusive granites elsewhere within the geosyncline. A few K-Ar ages, from scattered localities, conform generally with the later event or events which appear to have some connection with the structural deformation clearly observable both in the complex and the surrounding metasediments. It is these younger events which appear to match the residual evidence for the earliest detectable concentration of uranium minerals in the Alligator Rivers district.

Jan 1, 1977

By Forster G, Datta P. K

Many high temperature industrial processes involve gaseous halogen-bearing environments. Essentially, these fall into three subject areas: power generation, waste incineration and especially extractive metallurgy. Fundamental to any understanding of the process chemistry and efficiency in the process technology is an adequate knowledge of background thermodynamics relating to metal-chlorine reactions. In this context, existing free energy/temperature diagrams for metal chlorides do not include many elements, in particular the so called refractory elements from Group V and Group VI of the Periodic Table, namely niobium, tantalum and vanadium, and molybdenum. This paper reports estimation and calculations of the free energy values for these chlorides. The data is discussed in the context of high temperature chlorination processes.

Jan 1, 1991

The evolution of mineral sand mine rehab ilitation techniques have been techniqually based. Research and investigations have been carried out by government authorities, mining companies and academic institutions. Protection of the physical and biological environments is a vital part of any mine oper- ation. The Mineral Sands Mining Industry in New South Wales is successfully working within the State's environmental framework and is meeting; community requirements and expectations concerned with the environment and mine rehab- ilitation. Keywords: Environment, mineral sands mining, mine rehabilitation, revegetation.

Jan 1, 1986

By C J. Unger, T Baumgartl, C J. Bond, P Sabourenkov, V C. Glenn

Social licence to mine is influenced by society’s perception of the mining sector’s ability to effectively rehabilitate mined land and for governments to appropriately regulate that process for the broader community benefit. In Queensland, Australia, many mine rehabilitation personnel working for active coalmines, as either staff, consultants or contractors, belong to the Central Queensland Mine Rehabilitation Group (CQMRG). The CQMRG was established 23 years ago with the aim of sharing informal knowledge related to practical aspects of rehabilitation in order to leave as positive a legacy as possible from mined land. This voluntary group of professionals also includes members from regulatory agencies and civil society. Within the dynamic regional mining environment, mine rehabilitation professionals benefit from sharing their informal knowledge.CQMRG is currently a group in transition. Mining boom and downturn cycles have exacerbated the loss of accumulated knowledge in the core CQMRG membership due to rapid changes in personnel at mines in the region. Additionally, some of the most experienced CQMRG-affiliated rehabilitation practitioners are approaching the end of their careers and want their valuable and less formal knowledge retained. This paper discusses the development of a research project that emerged in response to the anticipated loss of several decades’ worth of valuable knowledge as rehabilitation practitioners in CQMRG left the region or the workforce.CITATION:Unger, C J, Bond, C J, Baumgartl, T, Glenn, V C and Sabourenkov, P, 2016. ‘MRC-wiki’ – a mine rehabilitation and closure knowledge management tool for Central Queensland coalmine practitioners, in Proceedings Life-of-Mine 2016 Conference , pp 39–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

Landscape interpretation, geology and mining history is being successfully used to explore options for sustainable community tourism product development. Recent work by the author in Europe and Australia has indicated the value of adding and producing interpretive information about mine and quarry locations - both active and inactive. This work has allowed for the branding and development of new sustainable community tourism products based on the landscape, folklore, mine and geological heritage.   Communities in rural areas are seeking new opportunities to sustain their local economies. Using a relatively new phenomenon called geotourism as a starting point; they have developed themed products connected to walking/cycling guides, interpretive panels and visitor centres. These themes can be linked to geology, archaeology, botany, local history and to industrial heritage sites such as old mines, to generate local employment. This new geotourism approach has successfully brought a new and greater audience to discover the value of geology and mining history.   Communities have established a unique place for themselves within the tourism marketplace using the geotourism brand. Other communities with an established tourism product are also now using geological and mine heritage via geotourism to rebrand and meet changing global trends. The pooling of resources under the banner of geotourism has led to cost effective marketing, targeting and promotion of products.   Geotourism has emerged strongly in Europe, North America and China in the last decade. The Australian minerals industry now has an opportunity to implement this new branding concept to assist and benefit the communities in which they run their activities. Communities can also take advantage of the potential to develop a sustainable geotourism business around a past or present mineral industry in their vicinity.

Jun 1, 2010

Developed and built in 1982 for simultaneous bathy-metric and reflectivity mapping of the deep ocean by the Hawaii Institute of Geophysics, SeaMARC II was a breakthrough in sea-floor mapping technology. The design was developed cooperatively by industry and academia, and the system has served as a prototype for a new generation of mapping tools for operation in both shallow and deep water.Research programs using the SeaMARC II system have focussed on basic research into the geophysical evo-lution of the Pacific, ranging from intra-atoll mapping to surveys of the deep-sea trenches. During the past few years most work has been concentrated on detailed investigations of the morphology of mid-ocean spread-ing centers, seamounts, and the subduction zones which surround the Pacific. The detail provided by the high resolution, 10-km wide side-scan sonar images of fault and fold structures, combined with the swath of bathy-metric information obtained simultaneously, allow previ-ously unattainable analysis of seafloor morphology and are leading to development of detailed models for ocean crust genesis and deformation.

Jan 1, 1990