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By S M Richardson, A W McNeill, J B. Gemmell

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Hellyer, Fossey, Que River and Mount Charter volcanic-hosted massive sulfide (VHMS) deposits occur within the Que-Hellyer volcanics of the Mount Read volcanics, Tasmania. These deposits occur along a 6 km strike length and are hosted by the same stratigraphic unit. We use a combination of whole-rock geochemistry, short wavelength infrared (SWIR) spectrometry, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses and compiled historic whole-rock geochemical data to develop district-scale vectors towards VHMS mineralisation.Strongly sericite and K-feldspar altered rocks concentrate along a linear trend from Hellyer, through Que River, to Mount Charter. Ishikawa alteration index values and whole-rock major and trace element concentrations provide exploration vectors towards mineralisation on a regional scale as significant enrichment and depletion trends. On a deposit scale, composition variations in white mica (sericite alteration), chlorite and K-feldspar are observed and reflected in whole-rock geochemical variations. Regional SWIR data from drill core support the prevalence of phengitic mica and high-Mg chlorite within footwall alteration halos and highlight the main upflow zones of hydrothermal fluids in the VHMS district. The combined use of regional whole-rock geochemistry, SWIR and mineral chemistry is an effective way to highlight prospective areas for VHMS mineralisation in a mature exploration province.CITATION:Wu, S, Gemmell, J B, McNeill, A W and Richardson, S M, 2015. Exploration implications from variations in whole-rock and mineral chemistry around the volcanic-hosted massive sulfide deposits of the Que-Hellyer volcanics, Tasmania, Australia , in Proceedings PACRIM 2015 Congress, pp 85–90 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By T Christie, A Swain

Patterns of quartz veining in epithermal gold-silver deposits at Wharekirauponga, Neavesville and Ohui in the Hauraki Goldfield, have been analysed to determine the effects of different lithologies on vein distributions. At Wharekirauponga, quartz veins are hosted in rhyolite and minor andesite, with the andesite containing slightly higher gold grades. Local basement andesite, rhyolitic tuff and silicified black shale host gold-bearing quartz veins at Neavesville. At Ohui, quartz veins are hosted in rhyolite, rhyolitic tuff and andesite. Fractal analysis was used to quantitatively describe the distribution of veining. The fractal dimension (D) of veining in silicified tuff is 0.25, moderately silicified rhyolite has D = 0.23 - 0.26, clay-altered andesite has D = 0.3, strongly silicified rhyolite has D = 0.3 - 0.39, silicified andesite has D = 0.4, and silicified black shale has D = 0.43. The D values are related to the composition of the host rock, and appear to be controlled by its competency. Hydrothermal silicification results in increased competency and higher D values. Vein thickness frequency plots for different lithologies show that andesite at Ohui, and to a much lesser degree at Wharekirauponga, contains more thick veins than rhyolite and tuff. Gold grades show a strong to fair correlation with higher vein density in three drillholes at Wharekirauponga. The fractal dimension of veining is an important control on fluid flow and gold deposition within an active epithermal system. Vein systems with higher D have a greater density of veining which would have favoured increased fluid-rock interaction. Lower D vein systems have more clustered arrays. The increased fluid-rock interaction induced by a high D vein system, when combined with a reactive host rock, results in an environment which is highly favourable for gold deposition. This situation is seen in the andesite at Wharekirauponga.

Jan 1, 1994

By J S-L Chan

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Cu-Ag-Au mineralisation at Kluwih prospect in Eastern Java, Indonesia is related to a high-sulfidation hydrothermal system within a volcanic dome (2.35 × 1.7 km diameter). The mineralisation occurs mainly in steeply dipping, structurally-controlled quartz-enargite-pyrite veins (several centimetres to 2 m wide) and is hosted mainly in porphyritic dacite, volcaniclastic rocks and volcanic breccia of the dome and in an underlying andesite that yielded a zircon U-Pb age of 11.5 Ma.Short wave infrared spectrometer analyses were carried out for alteration mapping at Kluwih. There are two main stages of alteration produced by the hydrothermal activity. The alteration mineral assemblages indicate an advanced argillic alteration. The Cu mineralisation occurred in the form of enargite and subordinate chalcopyrite with an intergrown texture in the early stage. These mineralised veins are characterised by narrow pyrophyllite ± diaspore and dickite selvages (metres wide) and a peripheral K-muscovite envelope (sericitic alteration) up to 100 m wide. The K-muscovite envelope is zoned outward to Na-muscovite or Na-illite. Late-stage kaolinite and smectite alteration overprints the porphyritic dacite and may obscure the nature of early mica-clay alteration. The spatial distribution of different alteration assemblages suggests that the temperature of hydrothermal fluid increases with depth.Both the high-sulfidation mineralisation and advanced argillic alteration are suggested to be related to magmatic-hydrothermal fluids, which are likely to originate from an undiscovered deeper porphyry Cu-Au system below the porphyritic dacite. Based on alteration mapping results and comparisons to similar deposits, the porphyry intrusion could be up to 500 m below the volcanic dome. Further geochemical and mineralogical studies may help to target the potential underlying porphyry system.CITATION:Chan, J S-L, 2015. High-sulfidation epithermal Cu-Ag-Au deposit, Kluwih, eastern Java, Indonesia – alteration and implications for potential porphyry cu mineralisation, in Proceedings PACRIM 2015 Congress, pp 213–218 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By C Chen, T Kan

The distribution ratio of Pb (LPb s/m) between three types of slags (FeOx–SiO2, CaO–FeOx and FeOx– CaO–SiO2) and molten copper after equilibrium was measured at 1300°C and oxygen partial pressure (pO2) of 10-10–10-6 atm. Results showed that for FeOx–SiO2 slag, the LPb s/m increased from 0.024 to 2.57 with pO2 increased from 10-10 to 10-6 atm. The LPb s/m with CaO–FeOx slag was lower than the FeOx–SiO2 slag at the same pO2, ranging between 0.015 and 0.53. Using the FeOx–CaO– SiO2 slag generated LPb s/m values (0.02–1.6) in between. The oxygen partial pressure in the investigated range had no obvious effect on the activity coefficient of PbO (γPbO) which was averagely 0.44, 1.70 and 0.71 for FeOx–SiO2, CaO–FeOx and FeOx–CaO–SiO2 slags, respectively. The increases in the (CaO+MgO)/SiO2 mass ratio of the FeOx–CaO–SiO2 slag induced the decrease in the LPb s/m and the increase in the γPbO value. However, the variation in the Fe/SiO2 mass ratio didn’t exert obvious effects.

Jun 19, 2024

By M Sherman

The challenge facing the engineering provider is to calculate throughput rates when faced with disparate specific energies calculated by different testing methodologies. Typically, an ownerÆs team would expect that the throughput calculations be checked using more than one method, therefore it is inevitable that there will be differences, based on which methodology is used. This engineering challenge is exacerbated by the continuing evolution of contemporary circuit configurations such as two stage pebble crushing with or without high pressure grinding rolls (HPGRs) as the second stage, or second stage pebble crusher product reporting to the ball milling circuit, etc.This paper is a companion to the paper first presented at SAG 2011, which showed that the Bond Indices are an excellent tool for estimating the specific energy requirements for semi-autogenous grinding (SAG) mills in single-stage SAG milling (SSS) circuits, SAG and ball mill circuits (SAB) or SAG and ball mill circuits with pebble crushers (SABC). This paper presents how the Bond Indices have been used to calculate ball mill specific energies, and therefore throughput rates, for SAG mill based circuits. Once the ball milling specific energy is known, tower mill and vertimill energy requirements can also be calculated. It is noteworthy that the method presented in this paper does not require the use of any unpublished correction factors: the proposed method uses the Bond parameters and equations published by Rowland in 1982.CITATION:Sherman, M, 2013. 21st century bond, in Proceedings Iron Ore 2013 , pp 309-312 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By J-S Han, J-M Yao

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Shagou deposit is located along NE-trending faults within the high-grade metamorphic basement of the Xiong’er Terrane in the Qinling orogenic belt. It is a large Ag-Pb-Zn deposit hosted in the Taihua Supergroup and has proven reserves of 1.54 Mt of ore with grades of 767 g/t Ag, 13.24 per cent Pb and 4.31 per cent Zn. The hydrothermal ore-forming process can be divided into early quartz-pyrite, middle quartz-polymetallic sulfides and late quartz-carbonate stages. Four types of fluid inclusions (ie pure carbonic, carbonic, pure aqueous and aqueous) can be distinguished in quartz. Fluid inclusion, hydrogen, oxygen and sulfur isotope systematics indicate that the ore-forming fluids are initially deeply sourced metamorphic water with meteoric water gradually mixed in the later stages. Sulfur isotope data show that the ore-forming fluids originated from both the Taihua Supergroup and the sedimentary successions of the Guandaokou and Luanchuan Groups (CSC) located to the south of the Machaoying Fault. A genetic model of the Shagou deposit is proposed as follows: CSC subducted northward along the Machaoying Fault beneath the Xiong’er Terrane during the Mesozoic collision between the North China Craton and South China Block. Subsequent dehydration resulted in the devolatilisation of fluids rich in CO2. These fluids migrated upwards, reacted with the Taihua Supergroup and formed the Shagou deposit.CITATION:Han, J-S, Yao, J-M and Chen, H, 2015. Fluid inclusion and isotopic constraints on the mineralisation of the Shagou Ag-Pb-Zn deposit, Henan Province, China , in Proceedings PACRIM 2015 Congress, pp 615–618 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By K C. Williams, A W. Roberts, J D. Prigge

For stockpile design, the flowability and structural interfaces are critically dependant on the stress conditions throughout the pile. Historically, the predictive methodologies for stress determination have been too conservative, which adds inefficiency to the stockpile reclaim interface selections, especially for live reclaim stockpile systems. In addition, accurate pressure profiling throughout stockpile is essential to correctly design the stockpile support structures, which are buried within the stockpile. Such buried structures include trestle legs or columns to support load-out conveyors or the roof of bulk storage sheds. Improved methodologies with respect to the development of the hoop stress condition which exists in material ædrawn-downÆ within the stockpile has been developed. This hoop stress approach has significantly improved the live capacity prediction to over 90 per cent accuracy and improved rathole structure prediction within live reclaim stockpiles. Additionally the methodologies in estimating the vertical and circumferential stress variation acting on buried stockpile structures have been significantly progressed, with experimental testing shown good agreement with the theory.CITATION:Williams, K C, Roberts, A W and Prigge, J D, 2013. Recent developments in stress analysis and live reclaim prediction within iron ore stockpiles, in Proceedings Iron Ore 2013 , pp 501-510 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By G Ma, L Qi, J G. Shellnutt

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Emeishan large igneous province (ELIP) of SW China is host to magmatic Ni–Cu–(PGE) sulfide and Fe–Ti–V oxide deposits which contain economic to subeconomic concentrations of precious and base metals. The formation of a given deposit-type (ie sulfide versus oxide) is thought to be related to the type of parental magma (ie high-Ti versus low-Ti) and the subsequent processes (ie fractional crystallisation and sulfide segregation), which allowed for metal enrichment.We examined the PGE of Baima and Taihe oxide-bearing layered mafic intrusions from the ELIP (Shellnutt, Ma and Qi, in press), and compared them with the nearby Xinjie and Hongge intrusions as well as with the Emeishan flood basalts. The PGE results for the two intrusions are contrasting. The Baima gabbroic rocks are almost PGE-barren (SPGE < 4 ppb) whereas the Taihe gabbroic rocks are variable, but generally much higher in PGE concentrations (SPGE < 2 to ~300 ppb), although the gabbros from both intrusions are enriched in platinum-subgroup PGE (PPGE = Rh, Pt and Pd) relative to iridium-subgroup PGE (IPGE = Os, Ir and Ru). Cu/Zr, Ni/Ir, Y/Pt, Cu/Pd and Ni/Ir systematics suggest that the Baima rocks were derived from a relatively evolved, mafic, S-undersaturated parental magma that was affected by earlier sulfide segregation. In contrast, the Taihe rocks record evidence of both S-saturated and S-undersaturated conditions and that the parental magma was likely emplaced very close to S-saturation. Through comparison of the PGE contents in the Emeishan flood basalts and the Emeishan oxide-bearing intrusions, we provide a self-consistent model for ELIP that the PGE budget in a magma is not strictly controlled by magma series (high-Ti versus low-Ti), but very much by crustal contamination.CITATION:Ma, G, Shellnutt, J G and Qi, L, 2015. Platinum group elements in the Baima and Taihe Fe-Ti oxide-bearing gabbroic intrusions of emeishan large igneous province and problems on propensity of magma series for sulfide- versus oxide-dominated deposit types, in Proceedings PACRIM 2015 Congress, pp 303–310 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Z S Chang, T F. Zhou, G X. Zhong

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Yaojialing zinc-gold polymetallic deposit is a newly discovered, large skarn deposit in the Middle-Lower Yangtze metallogenic belt, East China. It is located in the transitional zone between the Tongling uplift block and the Fanchang faulted basin. It is mainly hosted in the contact zone between early Cretaceous granodiorite porphyry and Carboniferous-Triassic limestone, or occurs in limestone xenoliths within the intrusion. Skarn and stratabound massive sulfide orebodies are the primary ore styles. Sulfide ?34SV-CDT values indicate a magmatic sulfur source, in common with most deposits in the Tongling block. Calcite d13CV-PDB and d18OV-SMOW ratios reveal that marine carbonates were the major source of carbon in late-stage hydrothermal fluids. The calcite probably formed during interaction between magmatic fluids and carbonate wall rock.CITATION:Zhong, G X, Zhou, T F and Chang, Z S, 2015. Geology, chronology and isotope geochemistry of the Yaojialing zinc-gold deposit, Tongling ore district, Anhui Province, China, in Proceedings PACRIM 2015 Congress, pp 457–462 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By J S-L Chan, J C. T Chu

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. In its industrial days, Hong Kong’s mining industry was thriving, benefitting from the mineral occurrences that are related to the regional Mesozoic igneous and hydrothermal activities.Hong Kong was unique in the mining sector as it was so small in landmass but with such a rich variety of commodities discovered. There are records of commercial exploitation of tungsten, iron, lead, silver, beryl, graphite, quartz, feldspar and kaolin in Hong Kong before 1981. Of these, most of them are located in the New Territories.The Lin Ma Hang lead mine was operated in the 19th century by the Portuguese and was abandoned in 1958. The Needle Hill tungsten deposit was discovered in 1935 during construction of the Jubilee Reservoir. The Ma On Shan iron mine, which operated for 70 years between 1906 and 1976, was the largest mine in the history of Hong Kong. The Mui Wo lead-silver mine on Lantau Island can be traced back to the Ming Dynasty 400 years ago. West Brother Island, which extracted graphite from 1952 to 1973, was levelled in the 1990s to make way for the development of the airport at Chek Lap Kok.Nowadays, these mines are disused and abandoned, but this extended abstract reviews the legacy of the mining industry in Hong Kong to understand the impact that it had on techniques, the economy and culture.CITATION:Chu, J C T and Chan, J S-L, 2015. The history of mining in Hong Kong , in Proceedings PACRIM 2015 Congress, pp 109–114 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.Low-sulfidation epithermal gold mineralisation at Ridge Mountain occurs within the Oligocene to Miocene volcanic rocks comprising andesite, porphyritic dacite and diatreme breccia. A diatreme breccia complex with a NE–SW elongated orientation covers an area of 3.0 × 1.7 km. Four main stages of mineralisation were identified, comprising: E–W- to NW–SE-trending quartz-chalcedony veins with disseminated pyrite, chalcopyrite and gold. N–S- to NNE–SSW-trending breccia veins with quartz matrix and disseminated pyrite and accessory sphalerite, galena, chalcopyrite and gold. NE–SW-trending quartz and calcite veins with disseminated pyrite and accessory sphalerite, galena, chalcopyrite and gold. ESE–WNW- to ENE–WSW-trending quartz veins with disseminated pyrite. This stage is only mineralisation that is hosted by diatreme breccia and clearly postdates.Quartz veins of the first, third and fourth stage are less than 2 m wide. Only breccia veins of the second stage are up to 10 m wide. Gold is present in all stages as microscopic inclusions in quartz and sporadically in pyrite. Macroscopic gold can be seen in the first and second mineralisation stages. Gold commonly occurs in association with sphalerite, galena and chalcopyrite in the second and third mineralisation stages.CITATION:Kucera, J, 2015. Diatreme breccia-hosted epithermal gold deposit at Ridge Mountain, eastern Mindanao, Philippines, in Proceedings PACRIM 2015 Congress, pp 587–592 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By A-A Latscha, C Boyle

Geological modelling has historically been done using sectional interpretation of paper sections or on a computer screen. Boundaries of geological units or grade shells are interpreted by a geologist section by section and the shapes are drawn onto paper to be digitised later or they are directly digitised into a computer. This approach is referred to as explicit modelling. Such methods are time consuming if there are many section lines or boundaries to be interpreted. The number of metres drilled and resource models made is increasing each year and it will be difficult to keep up using explicit modelling methods. Alternatively, it is possible to use information carried in the drill holes, known geological relationships and point estimation methods in two or three dimensions, to create similar geology boundaries, while eliminating or at least greatly reducing the need to manually interpret and digitise detailed sectional interpretations. Such methods are referred to as implicit modelling and are available in a number of software packages. Implicit modelling approaches have been used in iron ore and found to significantly reduce the time needed for modelling while producing results that are comparable or better than standard explicit modelling approaches. A number of case studies have been undertaken of implicit modelling in iron ore deposits. Stratigraphic surfaces of bedded, folded and faulted iron ore deposits have been modelled in various deposits by Leapfrog Geo, GOCAD (with SKUA) and Vulcan Integrated Stratigraphic Modelling. Leapfrog Mining was used to model iron grade shells at particular cut-off grades. The modelled surfaces are of a high standard equivalent to those that could be produced by traditional explicit modelling but the time required by the implicit methods is far less. Implicit geological modelling is an active area of software development and improvements in software are likely.CITATION:Boyle, C and Latscha, A-A, 2013. Implicit geological modelling of iron ore deposits, in Proceedings Iron Ore 2013 , pp 57-66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By M J. Bourassa

In addition to the geologic risk of a particular project, the criteria that an international exploration company (æIECÆ) utilises when making an investment decision in a particular country should also include a critical analysis of the political, judicial and fiscal regime of the host country. A key investment criteria of an IEC is mineral tenure and the security and continuity of that mineral tenure under the host countryÆs existing legal system as well as the host countryÆs overall legal, political and fiscal framework, the latter of which can affect the projectÆs overall economic viability in a number of ways. The authors, Steve Vaughan and Michael Bourassa of Aird & Berlis, Toronto, Canada, have taken the position that developing an understanding of a countryÆs legal tradition is a crucial first step in analysing the mineral regulatory regime of a particular country. This paper continues their efforts to overview the most recent legal trends affecting the worldÆs mineral industry and attempts to analyse, categorise, compare and contrast differing legal systems, cultural backgrounds and economic philosophies relating to the development of mineral rights in Pacrim countries and the resulting commercial, legal, and political framework which ultimately drives the relevant mineral legislation. For the convenience of organisation of this analysis, the authors have divided the Pacrim countries into four smaller groups, firstly, on the basis of their legal tradition and, secondly, by their geographic location:Common Law Countries: USA, Canada, Australia and New Zealand; Spanish Civil Code Countries: Mexico, Central America (Panama, Nicaragua, El Salvador, Guatemala), South America (Chile, Peru, Ecuador, Colombia). Communist or Former Communist Countries: Mongolia, China, Russia. Countries of the Pacific Southwest: Phillippines, Indonesia, Malaysia, Indo-China (Vietnam, Laos, Cambodia, Thailand), Papua New Guinea. The discussion starts with an analysis of the various types of legal regimes, attempts to classify or categorise them, reiterates the necessity for the rule of law and those factors which encourage mineral exploration and development and discusses and recommends the expansion of a practical country competitiveness rating system developed by the Fraser Institute. In addition to the fundamental issue of mineral tenure û what it is and how secure it is û the paper discusses how different legal systems have shaped different approaches taken by individual nations to attract foreign mineral investment. The paper analyses the best practices and experiences accumulated in different Pacrim countries with varying legal traditions and identifies a practical country competitiveness rating system which the authors believe should be expanded to cover all minerally endowed countries. This rating system will permit countries to identify their mineral regime weaknesses and adjust their legal systems to better attract mineral investment and will also permit exploration and mining companies to compare their jurisdictional choices with those selected by their competitors.

Jan 1, 1999

A new porphyry copper gold district has been discovered at Goonumbla near Parkes in central New South Wales. Endeavour 26 North is the largest deposit known to date with a possible resource of 166.4 million tonnes at 0.74% copper, 0.12g/tonne gold and 1.7g/tonne silver, using a cut-off grade 0.3% copper. Mineralisation is primarily bornite in the higher grade zones and chalcopyrite in the peripheral lower grade zones. Most of the copper, gold mineralisation is associated with potassic alteration. Two mineralised quartz monzonite porphyry intrusive stages have been identified and these are related at depth to a large monz- onite stock which may have been the source of some of the mineralisation. On the basis of detailed paragenesis studies, the potassic zone can be divided into three symmetric subzones. The low grade inner potassium feldspar subzone is confined to the later intrusive porphyry. The outer potassium feldspar subzone is the most highly mineralised alteration halo due to the focussed superimposition of two hydrothermal cycles which have overprinted intrusive and volcanic rocks. The fringing biotite potassium feldspar subzone reveals alteration minerals which are developed early in the paragenesis. Fracture controlled quartz sericite alteration with low sulphide content, fringes and, in part overprints the potassic zone. The restricted pipe-like nature of the alteration zones and related mineralisation suggests that Endeavour 26 North is repres- entative of a multiphase focussed porphyry copper gold system.

Jan 1, 1986

By D A-F Batchelor

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.South-East Asia represents the world’s most productive tin province, mainly from placers. Kalimantan has been a major diamond producer, while in the 1980s a placer gold rush occurred in Indonesia and Malaysia. Reviewing extensive geological and mining data highlights phenomenal palaeo-environmental changes in the Sundaland region, interpreted to be responsible for generating ‘giant’ placers. Correlation of the Late Cainozoic stratigraphy has been facilitated from mine exposures and drill holes distributed throughout Peninsular Malaysia, the Indonesian Tin islands and Kalimantan, including contiguous marine areas with extensive shallow seismic profiling data. Knowing the association of rich placers with palaeo-environmental episodes and stratigraphical units has been helpful to facilitate their discovery. All three placer commodities responded similarly to region-wide landscape evolution following Mio-Pliocene high sea levels. Commencing with major regression, important stages comprised: a long period of landscape stability with deep weathering during the maximum Sundaland extent gradually rising sea levels/precipitation initiated slumping of mineralised regolith to form fans, later reworked by braided streams with aggradation (Old Alluvium); during episodic pluvial periods downcutting upgraded placers significant change occurred around Middle Pleistocene time with peneplanation and pedogenesis from Late Pleistocene time ‘modern’ fluviatile deposition (Young Alluvium) filled incised V-shaped valleys.Placer seams show systematic variation in stratigraphic position, in particular cassiterite especially occurs in the Old Alluvium (equivalent Upper Dahor Formation in Kalimantan). Gold is commonly richer in gravelly younger deposits, partly because of secondary precipitation within permeable alluvium. Reworked diamonds are predominantly concentrated especially in younger fluviatile alluvium.CITATION:Batchelor, D A-F, 2015. Conceptual exploration for tin, gold and diamond placer deposits in ‘Sundaland’ (Indonesia and Malaysia) by understanding the late Cainozoic stratigraphic context, in Proceedings PACRIM 2015 Congress, pp 499–506 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Multiple regression analysis was used to predict elemental concentrations of copper and nickel in soils from consideration of the concentration of these elements in vegetation in an ultrabasic complex in New Zealand. Regression equations were computed from sixteen independent variables involving concentrations of ten elements in plant ash, and various physical factors such as slope and altitude of the site, and height of the tree. One elemental and one physical variable were significant for nickel at the 90 per cent level of probability and five elemental and two physical variables were significant for copper at the same level. Use of the regression equations explained 32·5 per cent and 26·5 per cent of the variance in the respective relative accumulations (amount in plant divided by amount in soil) of copper and nickel.Predicted concentrations of copper and nickel in soils agreed more closely with the observed values in the soils than did the levels of these elements in plant ash.Although the results may specifically apply only to the test area, the principles should have universal application.

Jan 1, 1972

A Study of Extracting Vanadium from Stone Coal Using Cyclic Oxidation

Sep 13, 2010

Several Approaches to Enhance the Bioleaching of Enargite Some approaches were investigated to enhance the recovery of Cu from enargite by bioleaching with Acidithiobacillus ferrooxidans using the galvanic interaction with pyrite and activated carbon, and with thermophilic bacteria, Acidianus brierleyi. Addition of pyrite initially enhanced Cu leaching by the Galvanic effect, but after that the formation of secondary minerals passivated the surface of enargite in inoculated batches. Activated carbon improved Cu recovery from enargite much better than pyrite, when it is contacted with enargite. Recovery of Cu from enargite has been recorded to at largest 2.4 per cent within 30 days in the presence of activated carbon when mesophilic bacteria were inoculated at 25¦C. The recovery of Cu from enargite was drastically enhanced by inoculation of thermophilic bacteria, Acidianus brierleyi, up to 60 per cent within 40 days at 70¦C and still not leveled off after 40 days unless the formation of Fe(III) precipitates occurred. After 40 days dissolved molar ratio of Cu/As is around 5.2, suggesting that metal-deficient sulfides and/or ferric arsenate might be formed on the surface of enargite.

Sep 13, 2010

IN 1906, soon after his arrival in New Zealand, a brief article was prepared by the writer on "The Salient Features of the Economic Geology of New Zealand," for the Journal of Economic Geology. In November, 1907, a somewhat similar paper, entitled "The Mineral Wealth of New Zealand," was read at the Royal Colonial Institute in London. The present contribution to the Transactions...

Jan 1, 1909

By P Allen, E Gleeson, D Boakye, R Chesher, S Konopa

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Not only do epithermal gold deposits provide many challenges in estimating mineral resources, the complexities of these deposits also provide technical challenges in assessing appropriate mining and processing strategies, as well as social and environmental planning and management. The characteristics of epithermal gold deposits include being highly variable with respect to geometry and gold grade distribution, the presence of other economic contributors, mineralogy, texture, rock strength, weathering and alteration overprint. These characteristics influence the economic value of mining projects in an interlinked manner. Consequently, successful exploitation of epithermal deposits requires a holistic approach, coupled with the effective integration of geological data to meet all aspects of mine development decision-making. This paper presents examples of the key technical challenges encountered in estimating and mining epithermal deposits. It also highlights why these issues need to be addressed from the viewpoint of geology, sampling, resource estimation, mine planning, mineral processing and social and environmental planning for the true value of the mining project to be realised.CITATION:Konopa, S, Chesher, R, Gleeson, E, Allen, P and Boakye, D, 2015. Challenges in maximising the value from epithermal gold deposits, in Proceedings PACRIM 2015 Congress, pp 127–132 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015