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The criterion for assessing the accuracy of coal reserve estimates proposed by Philip and Watson (1982) is criticized.Following Royle (1977), it is suggested that the global estimation variance found by geostatistical methods is more appropriate.This method is applied to coal data from the Bowen Basin. This shows that two factors (the inherent variability of the variable under study and the total number of drill holes) have more influence over the accuracy of the reserve estimate than the form of the drilling pattern. Comparisons between the relative errors for different sized regions demonstrate that the spacing between drill holes is of secondary importance. The dominant factor is the total number of holes.Comparisons between the relative errors show that some variables such as sulphur need a much denser sampling than the others to obtain the same level of precision.

Jan 1, 1983

By J Isarua, R Mabiria

The Ok Tedi copper and gold project, located in the Western Province of Papua New Guinea, commenced operations in 1983. The open cut mine has undergone several significant transformations throughout its project life including changes of ownership, mine life extensions and varying production performance profiles. As of today, the Ok Tedi Mine is a 100 per cent PNG owned company (67 per cent State and 33 per cent Western Province and Communities) and has a life-ofmine plan extending out to about 2032.

May 5, 2022

Differentiation of a basaltic (?) magma occurred in an active volcanic area during the late Miocene and Pliocene, and a change in the general mode of extrusion from fissure flow for the basalt to explosion for the andesite reflects an accompanying increasing magmatic viscosity. A caldera formed after the flow phase was completed and was filled with coarse agglomerate, much of which has a fused appearance. After an erosion interval its shape was modified and it became gradually deeper as repeated explosions from growing andesitic volcanoes caused large quantities of pyroclastic material to be deposited. At the close of this phase the floor abruptly collapsed when a, large block of the underlying crust was engulfed. The incompetent pyroclastics filling the caldera steepened in dip and the ensuing fractures were filled by the rising magma as dykes and sills and a chonolith formed below the caldera at a shallow depth. The ensuing activity reveals a further stage in differentiation and biotite is an important new ferromagnesian to be observed in the new rocks.Fracturing of the surrounding basalts was most intense in the rocks forming the periphery of the caldera where steeply and flatly dipping faults resulted from increasing horizontal pressure directed towards the caldera.Further differentiation resulted in the increased crystallization of orthoclase felspar, as evidenced by the numerous intrusives of trachy andesitic composition. Magmatic freezing caused mineralizers to accumulate at the top of the chonolith. These eventually escaped and auriferous pyrites, tellurides, quartz, and calcite were deposited in the surrounding rocks.The flatly dipping fractures are the most important and can be expected at various depths in a zone about 4,000 ft wide surrounding the caldera. Latest movement along these was controlled by magmatic consolidation rather than the shape of the caldera. Some flat faults were able to remain open during mineralization and acted as a feeder for the shallower fractures, thus limiting the depths to which the steeper dipping fractures were mineralized with the possible exception of one particular Nw.-striking lode (the Crown-Crescent).INTRODUCTIONThe gold deposits of the Tavua district were discovered in 1932 and from 1935 to June, 1961, 1,985,041 fine ounces of gold were produced from 4,202,504 tons of ore. Of the original three producers, only the Emperor remains active in the...

Jan 1, 1962

By R W. Wilson, F H. von Glehn

With ever-increasing energy costs and the modern focus on system efficiencies, the practice of æventilation-on-demandÆ is gaining momentum. Several examples, ranging from paper studies to practical examples have been recorded and another recent case study is presented here to encourage the practice. In comparison, æcooling-on-demandÆ has received far less attention. This paper explores the possible merits of this practice by investigating the theoretical response of cool intake airways and the thermal interaction between the air and the rock, in order to gain a better understanding of the system behaviour and to quantify the possible savings. A case study is presented that demonstrates the improvements that can be achieved. Recent developments that allow live interaction between ventilation network models and on-line monitoring systems, have the potential for intelligent active control and alarming of ventilation and cooling networks. This will facilitate and maximise the benefits to be derived from ventilation and cooling-on-demand.

Jan 1, 2005

Within ten months of the first significant intersection on the Vera deposit, approval was given to proceed with a $28.3 M underground development of the Vera-Nancy gold mine. Contrary to what the timeframe suggests, the development of the underground mine was planned in a logical and methodical manner which enabled confirmation of the resource, evaluation of the orebody for mining and sufficient production to recommence milling operations at the Pajingo treatment plant. This paper describes the underlying factors on which the project was planned and developed. The approach has successfully enabled the mine to be in production 18 months after discovery without compromising any future production or potential expansion

Jan 1, 1998

By T Napier-Munn, D J. Bradshaw, M Chauhan, L Keeney

An important aspect of geometallurgy is quantifying mineral processing attributes, which leads to improved orebody understanding. One of these attributes is flotation performance. Several methods have been developed as indicators for flotation performance, including batch testing leading to kinetic information and the standard grade-recovery curve. This paper makes a preliminary statistical comparison between a newly proposed geometallurgical batch flotation procedure and the æstandardÆ batch flotation test commonly used to measure flotation performance in the laboratory. The new test uses much less material than the standard test, and is much faster. It is concluded that the new method follows the final recovery of the standard method well, suggesting that it will be effective in reflecting ore variability for geometallurgical purposes. Comparison of the methods based on the full grade-recovery curve shows less agreement, but this may be due to the fact that the curve is sensitive to the particular experimental set-up and conditions, which make such comparisons quantitatively challenging. Further development work is therefore planned.CITATION:Chauhan, M, Napier-Munn, T, Keeney, L and Bradshaw, D J, 2013. Progress in developing a geometallurgy flotation indicator, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 201-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

This paper will review some of the work conducted in the past at the Dynamic Effects Laboratory to examine the use of stress waves and fracture mechanics in understanding dynamic fracture and fragmentation in blasting applications. Along the way, we will use photoelasticity and high-speed photography to better understand the mechanisms of fracture and fragmentation.CITATION:Fourney, W L, 2015. The role of stress waves and fracture mechanics in fragmentation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 27–40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Fullagar P. K

In resource definition and mine development, major capital expenditures are committed on the basis of sparse information and even in production surprises such as bad ground are not uncommon. Drill holes constitute the principal source of information about the orebody and its environment and optimisation of drilling implies maximising the yield of useful information per dollar expended. Geophysical borehole logging provides new flexibility for optimising the drilling budget. Economic benefits can flow from geophysical logging at all stages of the mining cycle. The most commonly cited benefit is substitution of diamond delineation drilling with cheaper percussion or reverse circulation drilling in cases where geophysical logs can substitute for core. This approach can deliver an attractive direct saving in drilling costs (and time) if drill meterage is unchanged, or a potentially greater indirect benefit from better ore control if more holes are drilled within the original drilling budget. More ore contact intercepts per dollar can translate into lower dilution and enhanced ore recovery, thereby increasing revenue as well as reducing mining costs. Substitution of diamond drilling with percussion drilling is not always feasible. However, geophysical logging of diamond holes is often highly advantageous in its own right, both for geotechnical characterisation as well as ore delineation. Operational advantages of logging include data objectivity, speed of interpretation and reduced core handling and analysis costs. Geophysical logging assists mining engineers by providing a continuous measure of in situ rock strength, even over intervals with poor core recovery. The additional expense of geophysical logging in blast holes can be justified in terms of more accurate ore boundary delineation and rock strength evaluation. Precise ore boundary delineation permits refinement of charge placement, to minimise dilution and maximise recovery. Detailed knowledge of rock strength can enable optimisation of blast design. Rock strength can be evaluated in real-time via analysis of drill performance data recorded with measurement-while-drilling (MWD) technology. To successfully apply geophysical logging in mines, its technical, operational and economic viability must all be established. This entails verification of the existence of appropriate physical property contrasts, investigation of the best way to integrate the geophysical results with the mining method and an objective assessment of the value of the resulting mine performance benefit. Geophysical logging is already well established in many mining operations. The greatest impediments to its wider utilisation at mines are: lack of appreciation of geophysics by most mine geologists, engineers and managers; limited interpretational aids; and the necessity to re-enter completed drill holes. In this paper we endeavour to address these issues by informing mine geologists about potential applications of geophysics, by illustrating automated interpretation of geophysical logs and by highlighting the importance of emerging MWD and logging- while-drilling (LWD) technology.

Jan 1, 1997

By A Prinsloo, R Tewu

Automatic control of semi-autogenous grinding (SAG) mills has often been considered complex. Recent experiences at Century Zinc (worldÆs second largest open pit zinc mine) refute this. Together with operating knowledge and appropriate control techniques high quality control is achievable. In this application model-based, constraint, and multiple output control were employed. The control was implemented using standard blocks in the plant DCS. The resulting overall control strategy fulfils the operating objectives and controls the mill with minimal operator involvement over 95 per cent of the time. Previous campaigns using expert systems and complex DCS based control have lacked durability. Their fall into disuse is briefly discussed.

Jan 1, 2009

By L H. G McClean

Diversity, equity and inclusion are often cited as ‘important priorities’ by mining companies and industry organisations in their public presentations and reports, but is the minerals industry really making strides forward? The mining industry is the least gender diverse industry in Australia (WEGA, 2023). Women make up just 22 per cent of the mining workforce and mining has a gender pay gap of 15.1 per cent (WEGA, 2024a). Only 8 per cent of the CEO roles are female and 20 per cent of boards have no female members (WEGA, 2023, 2024a). Gender diversity, equity and inclusion is a highly topical issue with the recent release of the Respect@Work report, Western Australia Parliamentary Inquiry as well as the publication of company specific workplace culture reports and the national legislative changes to implement a positive duty for organisations to prevent sexual harassment in the workplace. This comes at a time of a skills and labour shortage in the minerals industry as well as declining geoscience study and participation. This is a perfect storm for our future workforce. Governments, industry associations, networks and companies are developing and supporting initiatives to make strides towards equity and inclusion, with some shining examples on both an industry and company level, but the dial is only moving slowly and, in some ways, going backwards. Every company is unique, but every company can review and support gender diversity, equity and inclusion. Actions to progress gender parity could include establishing a clear company position; ensuring that this position is cascaded throughout the company with appropriate training; reporting and reviewing gender participation as well as supporting positive workforce initiatives and a positive culture with a people-centric issues reporting process. At the industry level, there are clear gaps in the support for gender diversity and inclusion including a national voice and ‘one-stop-shop’ to support women in the industry and provide resources. Recommendations include improved co-ordination and collaboration of support for women as well as improved promotion of the suitability (and safety) of the industry for women. The new independent organisation, Women in Mining and Resources Australia (WIMARA) has the objective to address the challenges of gender diversity and inclusion as well as foster co-ordination, co-operation and collaboration between the different stakeholders and state or territory groups and amplify reach. To deliver the future workforce that the minerals industry needs, the time is now for the industry to make some giant leaps for womankind.

Sep 1, 2024

Undisturbed minor sedimentary structures-cross-bedding, ripplemarking, scour-and-fill, slumping-are present in most of the rock types in the Willyama Series of the Broken Hill district and in the orebodies.This indicates that there has not been any significant movement of mineral matter within or into the rocks during or after metamorphism, that the rocks have not flowed during tectonic deformation or during metamorphism, and that the ore is an original sedimentary deposit in its sedimentary position.Sedimentary processes, depositional and mechanical, are indicated to explain the deposition of sedimentary metallic minerals and their concentration into large masses. The Broken Hill orebodies show evidence of these processes.INTRODUCTIONI visited Broken Hill for one week in May, 1958, at the invitation of Mr. Haddon F. King, Director of Consolidated Zinc Pty. Ltd. He asked me to examine the rocks and orebodies in the mines and outcrops at Broken Hill for:1. Sedimentary structures that might be used to determine the facing of the banding;2. Indications of the original nature of the rocks if I considered they may have been sedimentary; and3. Indications of any possible sedimentary origin for the ores.It has been stated (Gustafson et al., 1952, p. 30) that there was no indication, in the banding, of the facing of the banding, but recently B. P. Thomson had found examples of what he had interpreted as graded bedding (personal...

Jan 1, 1959

In the past decade several significant intrusion-related gold deposits have been discovered in terranes historically exploited for tin-tungsten mineralization (eg Tintina Gold Province, Yukon and Alaska, Tasman Fold Belt, Australia and the Altaid orogenic collage in central Eurasia). This paper presents new data on the geological and geochemical characteristics of these deposits that links them to magmatic-hydrothermal processes and highlights their implications for exploration. New data from several intrusion-related gold provinces suggest that these deposits are found in areas that contain granodiorite to granite, but with a locally significant mafic component, have Rb/Sr ratios ranging between 0.1 and 1.0, and are moderately reduced (Fe2O3/FeO ~ 0.1 to 0.6) ilmenite series, metaluminous, I-types. The intrusions are distinct from porphyry copper intrusions and tin granites, but are more akin to tungsten granites. Hydrothermal fluid types vary with depth of emplacement in intrusion-related gold deposits and new proton induced X-ray emission (PIXE) data from syn-ore fluid inclusions in shallow and deep deposits provide fascinating insight into the variation in metal content between the different settings consistent with observed deposit metal associations. Exploration for intrusion-related gold deposits in tintungsten terranes should focus on regions that contain both mafic and felsic intrusion that are moderately reduced, metaluminous, I-type granites rather than terranes with dominantly highly fractionated, strongly reduced, peraluminous S-types. Intrusion-related gold systems occur in variety of deposit styles (in part controlled by host rock, proximity to granite, and depth of emplacement) and exploration geologists need to be aware of the variety of target types in and around the intrusive environment, and be able to recognise whether they are exploring a shallow or deep intrusion-related gold setting.

Jan 1, 2005

Solvent extraction has recently been introduced into Australian hydrometallurgical practice for the production of a high grade uranium concentrate from El Sherana ore by a sulphuric acid leach and solvent extraction process. The solvent is a 5 per cent solution of tri(iso-octyl)amine in kerosene modified with 4 per cent of a long chain alcohol. The stripping reagent is a molar solution of sodium chloride.Preliminary testing for the development of the process showed that the leach liquor was quite amenable to the solvent extraction process and that the equilibrium and rate considerations of both the extraction and stripping steps were very favourable.The industrial plant contains four stages of extraction, three stages of chloride stripping and one stage of secondary carbonate stripping. An internal type of mixer-settler is used for the stagewise contact, the design being based on tests with model equipment.The performance and control of the industrial plant is satisfactory; 99·7 per cent of the uranium is recovered for a loss of 0·3 gallons of kerosene and 0· 4 pounds of amine per 1,000 gallons of liquor treated.INTRODUCTIONThe processing of El Sherana uranium ore from the South Alligator River valley commenced in April, 1959, and thereby introduced into Australian hydrometallurgical practice the unit operation of solvent extraction on an industrial scale. Although there are now some twelve mineral processing plants in the United States and Canada using solvent extraction, its application to the field of primary hydrometallurgy is quite new. Prior to 1956 none of these twelve plants was operating and hydrometallurgical application waslimited to the refining of comparatively high grade uranium compounds and fission products from nitrate and nitric acid solutions.

Jan 1, 1961

Geochemical projects in progress or recently completed in the Bureau of Mineral Resources, Geology, and Geophysics (BMR) cover a wide range of topics and include research projects, regional studies, and prospecting programmes. However, in these notes emphasis is given to projects which are directly relevant to mineral exploration.FIELD INVESTIGATIONSStream sediment sampling, rock and soil sampling, and geobotanical surveys have been used by the BMR in a number of areas, partly in attempts to locate specific zones of mineralization, and partly to investigate the effectiveness of the various methods under different conditions of climate and topopraphy and in different geological settings.Stream sediment sampling has been most successful in the Territory of Papua and New Guinea. For example, in the South Sepik area, zones of disseminated su1phide mineralisation were found to give rise to anomalies with peak values of up to 1,000 p.p.m. copper, compared with background values of about 40 p.p.m. (Dow et al., 1968). By contrast, the results of rather limited work in the Northern Territory and in the Kimberley district of Westen Australia were inconclusive.Rock and soil sampling, on the other hand, was successfully used in a number of areas in Northern Australia, particularly at Rum Jungle and Tennant Creek.Rum Jungle area In the Rum Jungle area, where uranium and base metal mineralization is mainly associated with a Lower Proterozoic black slate sequence, samples, of c-horizon soil or weathered 'rock are generally collectedfrom the bottom of drill holes, usually 15 to 20 ft deep, bored with a power-operated auger.Surface sampling indicates that such a technique would probably have shown up all the major geochemical anomalies delineated by deep sampling, but the latter gives slightly more consistent and slightly

Jan 1, 1970

By Maslov LA

We have considered the following characteristics of the crust and upper mantle of the Pacific Belt: seismic wave velocit> anomalies, mechanical stress and shear deformation rate fields, heat flow and the pattern of metallogenic provinces of the Belt. It has been noted that there exist certain regularities in distribution of the above mentioned geophysical characteristics and metallogenic zones within the Belt, displayed by prevalence of the lithophile elements in the Asia-Australian part of the Belt, and of the chalcophile ones within the American part.

Jan 1, 1995

The celebrations which took place in 1986 to mark South Australia's Jubilee 150 served to focus attention on all aspects of the State's heritage. Until that time the sites and relics of South Aus- tralia's early mines had been generally neglected. Marked by the ruins of enginehouses and littered with the remains of the massive technology of the Industrial Revolution, these sites have now been recognised as containing the threads of a fascinat- ing story. In the early days of settlement the economy of the Colony was based on land and farming. Droughts caused periods of economic depression which were alleviated by chance discoveries of gold, lead, silver, and copper ore. Some of the mines which were opened on the copper deposits were the largest in the world at that time and their names well-known throughout mining circles. Working by hand with primitive equipment, the early miners excavated vast networks of shafts and stopes often extending to great depths: at Moonta- Wallaroo Mines for example workings extended to 860 m below ground. Because of the presence of underground water, mining to these depths would not have been possible without the Cornish pumping engine. Operated by steam power these massive engines and their associated equipment were transported from Cornwall by clipper and delivered to the mines by bullock cart. At this time the engines were at the peak of their devel- opment and, although expensive to import and install, they were highly reliable: the engine oper- ating Hughes pump at Moonta worked continu- ously for sixty years without a major breakdown.

Jan 1, 1987

By A A. Latscha, D O’Connor

Increasing orebody complexity, restrictions in ground access, and longer lead times for disturbance approvals, have generated the need for the Resource Development Team within Rio Tinto Iron Ore (RTIO), to explore optimised drill design techniques that deliver resource conversion value while maximising program outcomes. In response to this challenge, the Team initiated a case study to produce an AI assisted/designed drill program using a non-machine learning AI. The case study involved the assessment and implementation of an AI generated drill program at one of RTIO’s Pilbara iron ore deposits, located in the Hamersley Province of Western Australia. The Mineral Resource is currently classified as 100 per cent Inferred. Access constraints inherent to topography, and the presence of exclusions zones have prevented adequate drilling coverage, resulting in lower resource confidence and a poor definition of the orebody extents and geometry. The drill campaign, planned in Q1 2023, needs to consider access constraints, complex topology and the limitations related to additional ground clearance, while addressing the requirement of improving orebody knowledge. The drill plan had to address two objectives. The first and main aim of drilling was to upgrade the Resource Classification to allow for possible conversion to Ore Reserve. The input for this objective was a volumetric representation of the areas currently not meeting pre-defined quantitative Resource Classification upgrade criteria. The second objective was to better define the orebody extents and geometry. For the second objective, the input to the drilling optimiser was a volumetric representation (blocks) of the areas of high uncertainty in the mineralisation/waste boundary, which were defined using an indicator conditional simulation technique. The drilling optimiser output was a range of compliant drill plans. A set of KPIs based on economic and orebody knowledge criteria were used to assess the plans and to select the most optimal drill design to be drilled in 2023. The geology and management teams were able to make better informed, objective decisions using the trade-off between cost and orebody knowledge gained. As part of the assessment, the AI generated plans were compared to our current planning practises. The AI assisted plans, when gauged against the project KPIs, showed clear and measurable improvements in both meeting project objectives and in managing operational risk.

May 24, 2023

This paper considers the standard of ore reserve assessments required by lenders when presented to support requests for project based loans. The way lenders use this information to structure a suitable financial package shows why ore reserves should be measured by industry set standards. This in turn raises questions concerning the assumptions used to derive mineable reserves from geological reserves. Consideration of the variety of related problems highlights the need for assessments to be defined according to acceptable standards. These should also address the suitability of the methodology to the assumed configuration of the orebody; the degree of variance and relaibility of estimates of grade and tonnage presented; and the estimation of probability that ore will in practice fall within the defined limits. In an increasingly international marketplace it is appropriate to compare Australian industry requirements to those of similar overseas industries, in this case the United States. Lenders would like to see that individuals responsible for the preparation of ore reserve estimates are certified on the basis of their skill and expereince by an industry body such as The AusIMM. The paper discusses how each of the parameters indicated above may impact upon a lender's assessment of the viability of a project. A number of practical examples are presented where inaccuracies or inadequacies in ore reserve information have led to reduced project performance.

Jan 1, 1987

By Ward S. C, Gardner J. H

In 1990, Alcoa of Australia Limited was elected to the Global 500 Roll of Honour of the United Nations Environment Program for the environmental management and rehabilitation of the bauxite mines in Western Australia. This award placed Alcoa in the international best practice category. The story of constant improvement spans more than 20 years from a 'trial and error' start to a strategically focussed and research driven program today. The main driving force has come from within the company, against a set of strong corporate values and a well publicised Vision based on 'excellence through quality'. Along the way public opinion, action group protests, increased legislative controls together with the professional competence of internal and external environmental resources have all played a part in arriving at the level of current environmental management and mine rehabilitation performance. There were numerous lessons learned here during the evolution and maintenance of best practice. These included: I . To work diligently in obtaining a vision or strategic intent on mine site rehabilitation and environmental management - don't be easily dissuaded.

Jan 1, 1995

Gas well tests were performed on 17 wells in the Roma area. The procedure used in the test programme incorporates an initial isochronal test followed by what is described as the "two flow drawdown" technique. The second flow of the two flow drawdown test was conducted for sufficient time to allow transient investigation of the surrounding reservoir. This combination of tests allows the evaluation of stabilized production capacity in addition to the determination ,of several important reservoir characteristics.It also provides a qualitative indication of reserves, by reflecting the presence or absence of reservoir boundaries within the drainage area affected during the test.

Jan 1, 1968