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The accuracy of an ore reserve is only as good as the geologist's understanding of the deposit. The methods that are applied to resource and reserve estimation reflect that understanding. At the Olympic Dam copper-uranium-gold deposit in South Australia, evolution in the understanding of the controls on mineralisation coupled with the changing demands of the project have led to changes in the approach to reserve estimation. The project has moved into a phase where detailed stope mining reserves are now required as distinct from global ore reserves. The complex nature of the mineralisation and the large amount of data demand that all available information be readily accessible in a flexible format. To enable the selective manipulation of geological and assay information and its characterisation, a relational database has been developed. For reserve calculations themselves, initial computations were based on a system derived from that used for the Kambalda nickel orebodies. The Olympic Dam system differed mainly in the use of statistical analyses in the estimation of grade instead of the previous polygonal area of influence weighting method, Three dimensional weighting techniques are now being used for local reserve estimates. Flexible facilities for raw data handling combined with grade estimation techniques which are commensurate with the mine geologist's understanding, produce detailed gridded and contoured ore zone models suitable for reserve calculations and stope designs.

Jan 1, 1987

By A B. Christie

The Institute of Geological and Nuclear Sciences' Mineral Resources Programme is currently carrying out research under two major projects:   HAREM (Hauraki Andesite Rhyolite Epithennal Mineralisation) The Hauraki Goldfield lies within a belt of andesite-dacite-rhyolite volcanics of Miocene Pliocene age which is underlain by a basement of Mesozoic greywacke. It contains some 50 separate epithermal gold deposits and is a world-class gold and silver producer. The HAREM project is aimed at improving models of the epithermal gold mineralisation, and to better understand the processes and controls of origin, transport and deposition of the gold.   MARGO - (Marlborough Gold) The MARGO project is aimed at determining the geological factors that controlled the formation of the Mesozoic mesothermal gold-antimony-tungsten deposits in the Marlborough Schist belt. Following reconnaissance work on 12 deposits, our current work is concentrated on deposits in the Wakamarina valley.

Jan 1, 1994

The Olympic Dam copper-uranium-gold-silver deposit, located approximately 520 km north-northwest of Adelaide, South Australia (Figure 1) was discovered in 1975 by Western Mining Corporation. A joint venture to facilitate development of the deposit was formed in mid-1979 between WMC (51 per cent) and the British Petroleum Group (BP, 49 per cent). Production commenced in 1988, and current annual output from the mining and treatment of 2.2 Mt of ore is approximately 65 000 t of refined copper and 1400 t of uranium oxide. Significant amounts of refined gold and silver are also produced.

Jan 1, 1993

By Cox N

Fragmentation control is perhaps the most critical aspect of quarrying operations, potentially impacting on the costs of all down stream processes, and sometimes even on the economic viability of an operation. The focal points of studies to control fragmentation are generally the pattern of blastholes, the accuracy of drilling, and the most appropriate powder factor. Recent studies suggest that the performance, and consistency of performance, of explosive detonation in the blastholes may also be a significant factor impacting on blast performance in hard rock quarries. This paper presents the results of studies of bulk emulsion and watergel explosive performance, using blasthole velocity of detonation measurements, and its impact on fragmentation. Field studies show a strong correlation between blasthole VoD and blast fragmentation. Another aspect of explosive performance impacting on ease of excavation of blasted rock is muckpile displacement, from which estimates of effective heave energy have been made for different bulk slurry (emulsion and watergel) products.

Jan 1, 1995

By I M. Platten, Y Xie

Narrow vein gold mineralisation generally contains both fine (<100 ¦m) and coarse (>100 ¦m) gold particles. The in situ size and shape, deportment, distribution and abundance of the particles controls deposit sampling characteristics, grade distribution and metallurgical properties. Particles can range from individual disseminated grains, clusters of particles and masses above 1 cm in size. At each end of the coarse-gold to fine-gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated gold particles, through to extremely difficult for very coarse particles. Deposits generally show a background grade of mineralisation dominated by disseminated fine gold particles. Drilling will resolve the background grade well, though is likely to considerably understate the grade related to the coarser gold particles. Gold mineralogy has a significant impact on metallurgy, with key factors affecting recovery being particle size, deportment, liberation parameters and silver content of gold minerals. For coarse gold particles the focus should be on liberation and the early removal of the particles from the mill circuit by gravity concentrators and gold traps. Finer particles will require more grinding to liberate prior to flotation or cyanide extraction. The determination of gold particle sizing is thus required to minimise evaluation and geometallurgical uncertainty and lower project risk.

Jan 1, 2008

By J Mauk, R Ruddock

The Taharoa ironsand deposit is 1600 hectares in size and is located 144 km south of Auckland on the west coast of the North Island, New Zealand. The sand predominantly contains heavy mineral-rich sediments, quartz, and feldspars. One hundred and two samples were collected from all areas of the mine, from the stockpile, black sand areas, tailings and Te Akeake Sands. Samples were collected with the primary focus on the next predicted mining path and secondly on gaining a good geographic spread throughout the mine. All samples were analysed for the dry, wet and particle density, the porosity and the magnetic, non-magnetic and clay minerals content.Stockpile samples had an average magnetic mineral content of 92 percent. Dry, wet and particle density values for stockpile material exceed all values from untreated ironsand samples with average values of 2.8g/cm3, 2.9g/cm3 and 4.4g/cm3 respectively. Black sand samples from the mine came from various areas such as the central area, the forest, the southern area and the benches. All black sand samples are remarkably consistent, with dry and wet density values between 2.3 û 2.5g/cm3 and particle densities that range from 3.7 to 3.9g/cm3. The porosity values are comparable to all other areas of the mine (average 37 per cent). The tailings and Te Akeake Sands have different physical properties due to their different mineral contents. The dry, wet and particle densities are all lower than that of all other areas with averages of 2.1g/cm3, 2.2g/cm3 and 3.3g/cm3 respectively. These lower values reflect the lower magnetic mineral content (average 18 per cent) and the associated increase in non-magnetic mineral content (average 78 per cent).

Jan 1, 2002

By H Kurth

Geoscan is used for multi-elemental analysis of conveyed bulk materials in real time. It has been used for coal analysis since the 1990s, in the cement industry, and since 2003 for measuring mineral ore quality. Geoscan-M has proven performance and demonstrated paybacks of weeks or months, in iron ore, manganese, copper, zinc-lead and phosphate industries. Geoscan-M measures continuously through the full bed depth and is unaffected by belt speed, particle size, layering and dust levels. Increments of two minutes (typically one to five minutes) are accurately measured and provide the plant operators with tonnage weighted results of each element within seconds.A Geoscan installed after crushing is able to measure quality shortly after mining. The analysis results can be used to divert the increments based on composition, such as diverting waste for disposal and diverting marginal material to a stockpile for processing at a later date. The bulk sorting process allows different qualities to be placed into relevant stockpiles for subsequent blending. Material meeting product DSO (Direct Shipping Ore) quality can bypass a beneficiation circuit to prevent unnecessary treatment costs. An analyser in a blending application enables proportioning of different quality feed materials from multiple stockpiles to achieve a desired compositional consistency for process feed. The parameter used for decisions may be; a) primary metal content, e.g. Cu, Fe, P, etc. b) deleterious component content, e.g. Mg as an indicator of talc content, c) process parameter content, or a combination of these. Process parameter content may be the elemental ratio between critical components, e.g. Cu:S ratio, Fe:Si ratio, basicity, Lime Saturation Factor, etc. or the content of an “indicator” element, e.g. Si as an indicator of material hardness or grindability.Measurement of the composition in real time enables prompt feedback to the mining operators and also feed forward to the process operators. Compositional variability can be critical in the process and advance warning enables appropriate reactions prior to processing. This may include modifying the feed rate, changing the feed blend (through additives), or modifying reagent dosing in anticipation of a change in feed quality. Benefits include, but are not limited to; reducing waste processing, improved feed grade stability, reducing energy, water and grinding media consumption, producing less tailings, increasing process efficiency, higher metal recovery, better plant utilisation, reducing plant downtime, better utilising mined material, all achieved using the same process plant throughput capacity.CITATION:Kurth, H, 2015. Optimising plant feed quality and process performance using Geoscan elemental analysis, in Proceedings MetPlant 2015, pp 373–380 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Dionne S, Goodwin F. E

Zinc-aluminium alloy cast matrix composites have been made by squeeze casting, pressure infiltration, spraying forming and stir casting. The overview describes composites made . with these processes. Improvements in properties compared to the conventional alloys are most significant at elevated temperatures. Since stir casting is the most economical viable route of producing composites, progress made in this area is particularly emphasised.

Jan 1, 1993

Arrow Energy NL has been operating a number of coal seam gas wells in the Darling Downs region of Queensland. At the time of writing this paper, the region is enduring an extended drought period. The local aquifers are depleting and have not been significantly recharged in over a decade. The local communities (both rural and townships) are struggling to obtain water. Currently, coal seam gas (CSG) operators (under licence) draw water from the coal seams as part of the gas production process and the majority of operators choose to evaporate this water, as it is characteristically brackish to saline in quality and as such must be contained. Although the water produced from one CSG operator is not sufficient to drought-proof the greater area of the Darling Downs, there is potential to supply smaller local areas and contribute to the sustainability of these communities. This paper outlines the work completed by Arrow and its local community partners on the Darling Downs to date, and discusses the application of the produced formation water for:stock watering in feedlots, as a feedstock for coal washing, as a potable water supply for Dalby, as an agricultural water supply for cotton farming, and use as a medium for growing salt-water fin fish.

Jan 1, 2006

The paper outlines the philosophies and the methods applied to resource estimation by North Flinders Mines Limited at The Granites. These are based on recognition of the prime importance of quality data, accurate geological perception of the deposit, and the judgement of the estimator. With reference to one particular deposit, East Bullakitchie, the series of resources statements published over a 5 year period is compared with the corresponding history of discovery and development. The comparison Illustrates:

Jan 1, 1990

During 1979 the writer had the privilege of interviewing about 50 people with varying degrees of involvement in the industrial arena and all of them in one way and another, had a part to play in the huge and intricate saga of Australian employee relations. They fell into the following' categories Industrial Relations Officers/Managers Academics Politicians Union Officials Representatives of Employer Associations Senior Industrialists Commission Members (State and Federal) Sundry (Journalists, Government Officials). This paper seeks to give an account of their views on various aspects of industrial relations. The interviews conducted were all on a personal and confidential basis so it can be expected that sources will not be identified. Suffice it to say that this account represents, albeit in "potted" form, the opinions of some of the most experienced individuals in the country. It will be seen that in most of the vital areas there is a remarkable lack of consensus. It should be noted that this lack of consensus existed within each of the groups mentioned.

Jan 1, 1980

By Colston M. B, Johnson I. D

The importance which matters of social welfare and environmental quality have assumed recently is the underlying theme of this paper. Demands for infrastructure reflect the change in emphasis from economic and technological development to those issues which affect the total well-being of the community. To put the importance of social change in perspective, examples are cited and a theme is developed which underlines the relevance of changes in public attitude and in government policies on mineral exploitation and related development and on the regimen of associated infrastructure sought. Planning on a long term or strategic basis and on a broad scale is put forward as an effective means of identifying changing social attitudes for the purpose of framing government and corporate policies. As a prelude to a section in which a description is given of a novel 'services baseline' concept and its use in the assessment of the current backlog of services

Jan 1, 1977

Economies in cemented fill demand the utilisation of the full potential of the portland cement component of the mix. If declined tailings are used, it is desirable to establish the optimum particle size distribution. Pozzolic materials and slags are. very useful additions to increase the amount of cementitious material through reaction with calcium hydroxide produced by hydration of the cement. It is also essential to check out the presence of substances which may seriously affect the setting and hardening of the cement or the durability of the cement bond. The importance of quality control in the preparation of cemented fill cannot be over Emphasised.

Jan 1, 1973

The ownership, policies, organisation, structure, market, financial considerations and communications of a large resource project vary significantly through its discovery, feasibility, development and production phases. The extent of these changes, from discovery in 1957 through to 1979, is examined for the Mt. Newman iron ore project in the Pilbara region of Western Australia and some of the factors that influenced it are detailed. This shows that only some of the influences are under the control of the mine owner/operator, despite their significant impact on the returns for the massive capital invested. The effect of the general business climate on the various phases is also examined.

Jan 1, 1980

The HYC mineral deposit at McArthur River is about 1.5 kilometres long by 1.0 kilometres wide and 55 metres thick, and contains 227 000 000 tonnes of ore of average grade 9.2% Zn, 4.1% Pb and 41 g/t Ag. Major studies have been carried out continuously since 1955 over the deposit and in the general region. This work is continuing. A small underground mine was developed by driving a decline tunnel to intersect the mineralization 80m below the surface. This provided a fully representative sample of the total deposit unaffected by weathering or oxidation, and was available for the major test program carried out in a pilot plant built to determine the full metallurgical charac- teristics of the ore. The pilot plant operations followed investigations by research institutions, both in Australia and overseas, into the problems of this ultra-fine grained ore. The ultra-fine grained nature of the ore required grinding to an average size of 95% passing 37 micro metres or 400 Tyler mesh. A major feasibility and environmental report was submitted to the government covering all aspects of a development program. The geological, engineering, metal- lurgical, economic, cultural and environmental submissions contained in this report were studied by external consult- ants employed by the government, who agreed with the conclusions that the McArthur HYC deposit is at present Uneconomic.

Jan 1, 1984

By J Pearse, N Acosta, N McIntyre, M Angarita, L Camacho, C Huguet, D Arbelaez-Ruiz, J Ossa-Moreno, O Restrepo

Colombia is an example of a nation where mining makes a significant contribution to local and national economies. Due to the abundant resources present in the ground, there are good prospects for further development. However, the impacts of mining projects can include reduced access to good quality freshwater for other economic activities and/or biodiversity preservation (Ossa et al., 2018). As well as the water management challenges common to all mining regions globally, Colombia has particular challenges associated with its biophysical and socio-political traits. Land use change in many regions is dynamic including rapid development of agriculture and the development and abandonment of small scale mines. The value of ecosystem services provided by prospective mining regions also creates challenges in particular with regard to the páramos, the headwater wetlands from which about 70% of Colombia’s water supply has originated (Cleef 1981). Colombia also has particular challenges related to strong preconceptions about mining and its impacts on water. On the one hand, there is recognition that new large-scale mines are important for Colombia’s economy; on the other, there is deep distrust of the sector’s ability to operate with minimal adverse impacts (Gutiérrez-Gómez, 2017). Hence, any impact assessment is likely to face high levels of scepticism and scrutiny. Summarising the work of McIntyre et al. (2018), this abstract proposes a framework for assessing and communicating risks to regional water resources arising from the impacts of mines. The framework outputs aim to provide government and other stakeholder groups the scientific evidence needed to inform their viewpoints about mining development in the selected region, and a baseline from which to design a program of priority scientific research. CITATION:McIntyre, N, Angarita, M, Acosta, N, Camacho, L, Pearse, J, Huguet, C, Restrepo, O, Ossa-Moreno, J and Arbelaez-Ruiz, D, 2018. A framework for assessing and communicating water risks in prospective mining regions of Colombia, in Proceedings Life-of-Mine 2018, pp 49–51 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Durucan S

The southern Attiki peninsula is a very interesting area from an environmental point of view. The port and the city of Lavrio is situated at the east coast of the peninsula with about 10 000 inhabitants and there are also a few villages in the vicinity. The south-eastern part of the peninsula hosts the famous Lavrio mines which exploited the silver bearing orebodies of the area for more than 25 centuries. As a result, soils around the city of Lavrio are polluted with high heavy metal loads. The area is also of archaeological interest, as there are well preserved remnants of ancient mining and processing plants and archaeological sites. Soil samples collected from an area of approximately 120 km2 around Lavrio were analysed for their metal contents and the spatial distribution of the concentrations of ten selected elements were estimated from these data sets. The spatial data analysis and transformation capabilities of Geographic Information Systems, combined with extensive mining and geological data, helped the authors to identify the extent and causes of metal pollution around Lavrio.

Jan 1, 1995

By Vanderberg B

A 3D, PC based computer program is currently under development by Blasting Analysis International, Inc., to analyze the kinetics of full scale blasts with two or more high-speed motion picture cameras. Todays common approach of utilizing only a single camera system can, in some cases, lead to great errors and erroneous conclusions when motion is assumed to be in a predefined plane of motion. CMe phrase, "What you see is what you get, it no longer true in 3D."). This is especially true in blasting environments which exhibit complex and/or predominant structural geology. The 3D system eliminates this problem, and includes automatic corrections for vertical and horizontal camera optic axis orientation, dimensional controls, lens distortion, field set-ups, projection imaging and digitized inputs. The only information required is the surveyed or known coordinates of at least six non coplanar points in the field of view. Motitn from each camera view is then digitized, transformed through a direct linear transformation, and processed with the 3D software, which also automatically time matches the data, even when the high-speed cameras are operated at different speeds. Eleven calibration constants are generated using an overdetermined system of linear equations to output the true 3D coordinates of motion in the time domain. Applications for this 3D approach are not restricted to just analyzing the kinetics of a blast. The system is sufficiently flexible to allow an accurate, quick and economical method of bench face profile analysis, generate muck pile profiles and estimate volumetric calculations. The recording systems for these applications can be common 35mm still photography and/or video equipment. It is envisioned that this system will soon replace expensive laser surveying systems at a fraction of the cost in the near future. It is also an excellent system to accurately quantify drill pattern layouts and the spatial locations of each blasthole. This information is required for generating single hole based synthetic seismograms to accurately predict the vibrational outputs of full scale blasts. In terms of litigation concerning claims resulting from blast induced ground vibrations to structures, the system is proving to be an excellent and economical method of performing pre-blast surveys where differential settlement is suspect.

Jan 1, 1990

By Wu Y. H, Lu J. P

Slope stability has now become a practical tool in the design and oper- ation of open pits. The stability of rock slope depends on many factors, including not only structural geology, the existence of weak layers, ground- water, blasting and weathering, but also the virgin stress field. This paper presents an application of a numerical method to investigate the effect of the virgin stress on slope stability. The finite element method is employed to simulate the excavation of open pits. Redistributed stress fields in the slope of open pit are computed for several different virgin stress fields. Based on the redistributed stress fields, the shear force which tends to produce sliding of a rock mass and the frictional resistance to sliding are evaluated. The possibility of potential failure is assessed by the limit equilibrium method. The combination of the finite element method with the equilibrium method provides a powerful analytical tool for slope stability. The significant effect of virgin stress on the stability of slopes is shown by studying a typical case.

Jan 1, 1989

Graded macadam slag base has been used successfully by the Department of Main Roads, N.S.W., in the construction of Expressways. However, the use of graded macadam in urban conditions introduces problems which can be avoided by the use of material meeting the specification outlined in M.R. Form 744. This paper outlines the rationale behind the technical requirements of the specification for the "Supply of natural gravel or crushed rock for road pavement (bitumen surfaced) M.R. Form 744". A blend of materials produced from slag is proposed as a potential solution for the production of slag base which would be suitable for use in urban construction or maintenance of roads.

Jan 1, 1979