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The information requirements of the Australian Stock Exchange Ltd for listing and reporting seek to ensure that the market is fully and correctly informed in a timely manner. This discussion confines itself to the technical reports from mining companies required for prospectuses, information memorandum, quarterly, annual reports and any other announcements to the Exchange. The Exchange requires that technical reports are produced by suitably qualified and experienced personnel and, in the case of a company listing, that these personnel have no interest in the company to be listed. Further, the Exchange has draft prospectuses reviewed by other independent suitably qualified and experienced personnel.

Jan 1, 1987

By A Hilli, K Kosmara, J Steyn

PT Nusa Halmahera Minerals (PT NHM) is an Indonesian joint venture company owned by Newcrest Mining Limited (75 per cent) and PT Aneka Tambang (Persero) (25 per cent). PT NHM operates two underground gold mines, Kencana and Toguraci at the Gosowong mine site in North Halmahera District, North Maluku Province, Indonesia.On 8 February 2016, a major ground movement occurred in the K-Link orebody of the Kencana underground mine, effectively blocking the only two access ways to the stoping area. Following mine clearance, it was found that a Solo production drill rig operator, who had been drilling in the Level 10 Extraction Drive was still underground, cut off from the rest of the mine by the ground movement.Communication, nutritional and logistic supply to the trapped operator was established with the breakthrough of two diamond drill holes. A range of technical expertise and opinions from both on and off-site were sought and two options were chosen for implementation of the rescue operation. The rescue was completed successfully on 16 February 2016 with the operator being rescued in good physical and mental health.CITATION:Kosmara, K, Hilli, A and Steyn, J, 2017. Eight days entrapped – PT Nusa Halmahera Mineral’s rescue of a trapped miner, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 155–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

It is often said in business that if you donÆt have a customer you donÆt have a business. The same rule applies to project evaluation; if you donÆt have customers you really donÆt have a viable project. It is therefore essential that in the early stages of project evaluation the following fundamental questions are addressed: What products will this project produce? Who are the potential customers? What are the customersÆ requirements with respect to grade and impurities? Do they have adequate capacity to take the production from the proposed project? Will the products introduce adverse effects in the customerÆs process circuits? Will additional waste streams requiring disposal be produced? In the past the attitude has been along the lines of the customer will take whatever we produce at the mine site. Times have now changed with customers now operating under much tighter environmental regulation with waste disposal becoming increasingly difficult. It would therefore be prudent that the principles of product stewardship be used as a tool in project evaluation. This paper will provide a general discussion on customer requirements and provide detail on case studies of the impact of mine products on smelter process circuits. It will provide examples where there were synergies between the mine product and the smelter circuit and where the mine product had adverse impacts on smelter performance.

Jan 1, 2007

The classical view of island arc geology is that of a plutonic intrusive/volcanic extrusive complex, derived from the products of oceanic lithosphere subdu.ction and constructed on an over-riding plate of oceanic origin. Such an arc is typically backed by a marginal basin, formed by seafloor spreading of a more or less conventional kind. Various studies undertaken over the last decade have modified this picture and provided a new tectonic framework within which to explore for resources. Formation of Marginal Basins During the 1970s, seafloor spreading magnetic anomalies were identified in various marginal basins in the SW Pacific. In one of these, the South Fiji Basin, there was clear evidence of a ridge-ridge-ridge triple junction, although no kinematic relationship to the major plate boundaries was determined. Palaeomagnetic studies conducted in Vanuatu and Fiji, and in the Bismarck Archipelago of PNG provided evidence of large scale arc rotations relative to major plates. This indicated a general pattern of marginal basin formation by ridge-ridge-ridge triple junction growth together with island arc growth by trench-ridge-trench triple junction evolution. Formation of Primitive Island Arcs The triple junction growth model strongly suggests that at least a significant amount of arc evolution occurs by the initiation of subduction at a spreading ridge. This has predictive implications for the nature of island arc basement.

Jan 1, 1987

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

The type of population encountered in the sampling of coal, ores and other products of natural phenomena is one in which the variance within a cluster of elements generally increases steadily as the size of the cluster increases. To enable estimation of variances of stratified random or systematic sampling for such populations one must model the serial correlation function or alternatively, the variogram function. The author has postulated a specific symmetry of the serial correlation function which leads to expressions with rich theoretical and practical implications. These expressions provide a spatial correlation function which explains power law relationships often observed in studies of dispersion variances. They also enable straightforward calculations of sampling variances. The importance of the role of finite population size in the equations leads one to examine previously held concepts of ælargeÆ and æsmallÆ sample populations. The model based on the symmetry postulate is a fractal model with the serial correlation function of a hypothetically infinite population being of the same form as that developed by Mandelbrot for discrete fractional noise. Techniques used in fractal mathematics apply, including box counting and fitting of a dimension function. The paper establishes a framework for the understanding of this fractal theory and demonstrates how to calculate sampling variances from the model variogram using simulated data fitting the model.

Jan 1, 2008

The aim of all modelling is to replicate geological reality as closely as possible using available data. This paper is aimed at one end of the spectrum, where very limited data is combined with intuitive geological ideas to synthesise models for either target definition or for determining minimum viable mining scenarios. Interactive 3D modelling allows a satisfactory hypothetical geometry of surfaces to be assembled, and provides a fast quantitative method for generating targets. As data flows from exploration, an evolving geological model assists with the progressive evaluation of a prospect. Two case histories are described where this approach has been used successfully, the Mosquito Hill Prospect in Queensland and the Longwood Ranges Platinum Prospect in New Zealand. The possibility is also discussed of hypothetically modelling an orebody which has yet to be discovered. The proper description of an orebody is the foundation upon which all mine design and planning is undertaken. The volumetric accuracy of the model is crucial in valuing an orebody. Geologists must form a geometry which matches the conceptual view of the ore occurrence and ensure that they understand how the computer system used calculates volumes. If the underlying assumptions inherent in the method conflict in any way with the conceptual model visualised for the ore occurrence, then that method must not be used.

Jan 1, 1995

In 1965, Peter Flawn author of the famous text-book on Mineral Resources (1966) published a paper in Economic Geology with the delightful title `Who took the `Economic' out of Economic Geology?'. He opened this most interesting article with the following paragraph:If one were called upon to cite an example of a fish out-of-water he could hardly pick a better one than a recent graduate of geology of an America university who is suddenly faced with the responsibility of evaluating or appraising a mineral property. And I venture to say that the 'ftsh' with a doctorate - even in economic geology - is not much better equipped than one holding a lesser degree. The new graduate with a major in economic geology probably knows the significance of the various sulphur isotopes, he surely knows a great deal about the chemistry of the ore forming fluids and he recites with ease the arguments which prove deposits are epigenetic rather than syngenetic. However he is a rare bird indeed if he knows anything about the economics of the mineral industry. The truth is that geologists who are engaged in evaluation work are largely self taught. I ask my more distinguished and experienced colleagues - `Has it always been this way? Who took the `economic' out of economic geology?

Jan 1, 1993

THE following paper is a description of the plant and operations of the above company in their recovery and treatment of the quartz tailings deposited as final residues by the various mining companies. at Waihi, Karangahake, and Waitekauri into theOhinemuri River. During the past few years the silting of the Ohinemuri River has increased to such an extent as to cause considerable interest and discussion, and has lately been the subject of a most extensive inquiry by a Royal Commission, to consider the best means of dealing with what is generally spoken of as a public nuisance.Ever since the commencement of mining in this district, which was opened as a goldfield in 1875, the various mines operating have been discharging their tailings into this river, it having been proclaimed a sludge channel in 1895. Up to the year 1900 the quantity of quartz crushed was not large, probably not exceeding 500,000 tons; but since that date the annual tonnages discharged have increased enormously, and at the present time would total from 550,000 to 600,000 tons per year. Records show that up to the end of 1910 at least 5,000,000 tons have been crushed, for an actual yield of bullion considerably exceeding £10,000,000 in value, and all the valuable tailings from...

Jan 1, 1911

Although the flotation cell has been under continuous development over the past 80 years, an understanding of the precise roles of a cell in produc- ing the flotation result had evolved slowly. In fact, detailed studies of cell dynamics began only in the 1940s when flotation practice had almost reached the half-century mark. The earliest generalizations related cell capacity to power intensity (hp/vol- ume) (Rose, 1946), and specific operating features such as aeration and power ' consumption to impeller submergence and operating speed (Read, 1933). In the 1950s hydrodynamic characterization of cells through power coefficients and air flow numbers began (Arbiter and Harris, 1961) and has continued to the present, with increasing industrial use of these concepts (Degner, 1982; Degner and Treweek, 1976). Liquid flow measurements in Wemco cells (Degner, 1982) made liquid flow numbers and turnover frequencies available for more complete under- standing of cell dynamics. The present overview of flotation technology is a critique of cell design. The cell process represents the interactions between cell dynam- ics, cell geometry, and ores, with the latter prepared for that interaction through size reduction and reagent treatment. While previous invest- igations of flotation cells have accepted all cell designs uncrit- ically, the present study considers the physical process components that an effective cell must provide, and then compares a limited number of

Jan 1, 1984

By Lin Bin, Minggao Qian, Zhiyi Yang, Fullan He

There are no efficient methods and instruments available in China at present for diagnosing the leakage problem for a hydraulic support system in underground coal mines. A new method has been developed to solve the problem. It is proposed that

Jan 1, 1998

By C M. Rebagliati, J G. Payne, K Roberts

The Pebble deposit, located in south-west Alaska, is one of the largest Copper- Gold-Molybdenum (Cu-Au-Mo) porphyry systems in the world, with a current resource of >8 billion tonnes which contain 73.7 billion pounds of copper, 87.1 million ounces of gold and 4.16 billion pounds of molybdenum. The Pebble deposit formed at ~90 Ma, during emplacement of subduction-related hornblende granodiorite porphyry intrusions emplaced into Jurassic-Cretaceous sedimentary, volcanic and subvolcanic intrusive rocks of the Kahiltna Terrane. The Pebble West and Pebble East Zones represent two thermal and fluid centres in a single large magmatic-hydrothermal system. The West Zone extends from surface to about 500 m depth, has thin zones of oxide and supergene mineralisation overlying hypogene chalcopyrite mineralisation, and is amenable to open pit extraction. The East Zone extends to at least 1700 m depth, is higher grade, occurs beneath an eastward-thickening cover of younger sedimentary and volcanic rocks, lacks oxide and supergene mineralisation, and is being evaluated for underground block-cave mining. Most Cu-Au-Mo was introduced with early K-silicate alteration and related quartz-sulfide veins. In the East Zone, a structurally-controlled overprint by advanced argillic alteration significantly increased Au and, to a lesser extent, Cu grades. Exploration potential at Pebble and its surrounding district remains high. Several other porphyry, skarn and epithermal deposits have been discovered in the district, but only limited exploration has been conducted. The eastern, higher grade part of the Pebble deposit remains open in several directions, with significant potential for resource expansion by ongoing, aggressive drill exploration. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

It's my privilege to welcome you here this afternoon on behalf of the Sydney Branch of the Australasian Institute of Mining and Metallurgy. This is a most important gathering. You, the delegates, represent what is probably the most influential cross-section of the mining investment community and the oil and gas investment community to meet as a group during the last decade. We are meeting today and tomorrow to review two related issues that will have far reaching implications for the effective use of capital by the natural resources sector in the 1990's. The views which will emerge over the two days will almost certainly 'influence the availability of new capital to the companies in the natural resources sector for the decade ahead. The two principal themes of Minval '89 are, first, the valuation of mining and oil and gas assets and securities, and second, disclosure and reporting requirements in the capital markets which relate specifically to natural resources companies. This conference is taking place at a time when further consolidation and rationalisation appears likely within the mining industry. Although the base metals and other sectors of the industry are enjoying profitability not seen since the early 1980's there is caution about committing to new capacity which could bring about a return to the low prices and excess supply which prevailed during much of the last ten years. These conditions have led to increased takeover activity within the mining industry overseas, and similar trends are as evident here in Australia as they are elsewhere. Recognition of value is therefore likely to become more important than ever before in preserving shareholder wealth, for creating new wealth and for preserving the financial health of the resources industry in the future. Valuation therefore is the first theme of the conference.

Jan 1, 1989

A significant resource of uranium has been discovered within a buried palaeochannel located in the south western corner of the Officer Basin of Western Australia by PNC Exploration (Australia) Pty. Ltd. The mineral- isation is redox controlled and is hosted by Eocene organic rich paludal sediments. Prob- able insitu reserves are 13,000 t of contained uranium with an average ore grade of 0.12% at a cutoff grade of 0.03% U. The Mulga Rock palaeochannel has been traced for at least 100 km beneath the Quaternary surficial cover. The main channel is horseshoe shaped with the channel arms vary- ing from 5 to 15 km in width. The western arm connects to the Lake Raeside-Ponton Creek drainage system, whilst the eastern arm'is open to the south. The headwaters of the palaeo- channel are thought to have been the Lake Minigwal drainage system, prior to its capture by the Lake Rason system. Differential.erosion of the basement rocks during the Late Cretac- eous to Early Tertiary strongly influenced channel shape and resulted in the main channel being confined to a Permian,mudstone filled valley. Upwards of 100 m of fluviatile sediments accumulated within the palaeovalley during a period of subsidence in the Early Tertiary. Three broad stratigraphic units have been re- cognised within the channel: 1. An upper unit of fluviatile sands with interbedded lacustrine sediments, which have subsequently been wholly oxidised and variably silicified and ferruginised. 2. A middle unit of lacustrine to paludal sediments, which host the main mineral- isation. 3. A basal unit of fluviatile gravels and sand. The presence of excellently preserved Nothofagidites in organic rich paludal sediments from the middle unit, suggest that unit was laid down in a non-marine, fluviatile, humid environ- ment during the Middle Eocene.

Jan 1, 1988

Titanium dioxide (TiG ) is produced 2 commercially by two methods generally referred to as the "sulfate" route and the "chloride" route. The SCM Corporation, in supplying 15% of the world's demand for TiO 2, uses both of these processes. Of the two processes the sulfate route is generally regarded as the older and more established technology. Worldwide the sulfate route accounts for some 70% of total Ti02 production. However, in the U.S.A. the chloride process accounts for 80% of production. The processes vary in chemistry and raw material requirements. In the "sulfate" process finely ground ilmenite or titanium slag is digested with sulfuric acid to produce a porous "cake" vrnich is extracted with water and recovered liquor. The solution is treated with scrap iron to reduce any ferric ions to the ferrous state which is then crystallised and removed as ferrous sulfate heptahydrate. The liquor is concentrated by evaporation and hydrolysed to form the insoluble hydroxide which is filtered and washed free of impurities. This is converted to the dioxide by calcination at 800 - 1000¦C and milled to break up any aggregates. The "chloride" process uses a higher quality feedstock of natural or synthetic rutile and/or high grade titania slag. The feedstock is mixed with ground high-purity coke and chlorinated at 950¦C in a fluidised bed. The resulting crude titanium tetrachloride is purified by distillation and chemical treatment. The purified titanium tetrachloride is burned with oxygen or oxygen enriched air to give titanium dioxide and chlorine, which is recovered and recycled to chlorination. Titanium dioxide pigment from both processing routes undergoes similar finishing techniques. It is subjected to further stages of wet and dry milling, then coated with layers of inorganic oxides in order to enhance its properties for specialist applications.

Jan 1, 1986

In this paper presented are the criteria used when assessing the harmfulness of shocks affecting the buildings. Those criteria are based on the value of speed or accelerations of building vibrations. Presented is the scale of harmfulness of vibrations of Langefors and Kihlstrom, Bureau of Mines, and SWD contained in the Polish Norm PN-85/B-02170. The parameters of the mining shocks measured by the Lubin coal mine station were compared with the parameters calculated as per the correlations (regression curves). The average acceleration calculated from the correlations for eight measurements is only two per cent higher than the actual one. But the average frequency of vibrations calculated from the correlations for eight measurements is as much as 2.22 times lower than the actual one. In order to analyse whether that takes place in the whole range of the energy of shocks compared were the results of calculations from the correlations for various magnitudes of shocks and various distances from their epicentre with the results of the measurements. From that it follows that only for the shocks of the highest energies the lowering of the frequency of vibrations by two times causes movement from the higher zone of harmfulness to the lower one (for example from the IV to III). In the one-family houses in Lubin there were the damages that are characteristic for not only for the III but also for the IV sphere of harmfulness as per the SWD scale. That should be explained via further research and maybe it would be feasible to draw out a new correlation to determine the frequencies only for high values of energy of shocks and determine the preciseness of the acceleration and frequency correlations used presently.

Jan 1, 2003

The smaller mining company with full ownership of, or participation in, a mining project is generally unable to obtain funding as easily as the major mining house. While the equity market remains the main funding source for small projects, debt fund- ing options are becoming more available. Many international banks possess in-house mine fin- ancing expertise which can assist the smaller company in financing its share of project development. A clear understanding is necessary of both the benefits and limitations of bank funding, to ensure that all potential sources of funds are properly considered and integ- rated into the financial plans of the smaller mining companies.

Jan 1, 1984

By M Lewis, A Cook

This paper is based on the technology and functionality of a Modular Mining IntelliMINE« system which is a real-time decision-making tool. The IntelliMINE« system, incorporating Dispatch, is a fully Integrated Mine Management System. Measuring, quantifying and analysing the performance of mining is considered a fundamental and strategic step towards changing the nature of technical and operational decision-making at the majority of international mining corporations. Successful implementation of electronic data capture devices and computerised tools have enabled many mining operations to improve their competitive position with an improvement in the utilisation of the key assets, mineral resources, capital mining equipment and human resources. Real Time Mine Management Systems are designed to direct the emphasis away from collecting data and focus decision makers on the real issues with well-presented and reliable information. The systems provide a common stream of information to enable senior management, operations, maintenance, technical and process plant staff to make complementary decisions based on reliable, accurate and timely data. The mine asset information tools focus all employees on performance and give them feedback on their area of responsibility. The resulting tangible benefits can be delivered in different forms depending on the mining method, ore type, workplace culture and the current competitive position. Typical areas of improvement reported by system users are:reduction in capital expenditure on mining equipment fleets; more effective planning and budgeting parameters and procedures; increased control over ore-extraction and processing; increased employee accountability and organisational performance; and improved co-ordination between planning, operations, maintenance and processing. These improvements can be delivered in different forms depending on the status of the mine and commodity markets. In times of market oversupply and low commodity prices, the benefits can be delivered to the bottom line in terms of reduced cash costs, reduced capital and operating resources to maintain constant production. In times of market expansion, existing capital resources will be more productive delivering increased production and revenue. Mine management systems have the potential to transform a traditional mine operation into a learning organisation with an improved understanding of the critical performance issues and enable development of relevant strategies to continually identify and eliminate operational inefficiencies. The effectiveness of each strategy and operational change can be accurately monitored and its success (or otherwise) will be quantified. The latest downturn in the world metal prices has forced many mining companies to focus on cost reduction and productivity improvements as a means of remaining competitive. Maintenance represents a significant proportion of the overall operating costs in the mining industry. A structured proactive maintenance approach such as Reliability Centered Maintenance (RCM) can achieve significant cost reductions and productivity improvements. Remote condition monitoring systems are becoming increasingly commonplace and have the potential to identify problems prior to failure. Detection of equipment degradation prior to failure will enable repairs to be scheduled, thereby reducing costs and interruptions to production.

Jan 1, 2000

Gold was discovered in the Bendigo area of Victoria in 1851 (Willman and Wilkinson, 1993), and all the early gold mining of any note involved washing (puddling) the gold out of the regolith or alluvium. The waste material from this process was a semi-fluid mixture of rock debris, soil and water, referred to as `sludge'. Puddling machines were gradually introduced to speed up the puddling process (Cole, 1994), and by 1855 an estimated 2000 machines were in the district (Anderson, 1978). In 1859 it was estimated that approximately 2 293 000 m3 of material was puddled annually by the machines on the eastern side of the goldfield, whose waste drained into Bendigo Creek and its tributary gullies. It was also estimated that after the gold was removed, approximately one-quarter of the residue/sludge consisted of the heavier, coarse-grained material which settled out fairly quickly, while the remainder, approximately 1 720 000 m3, was the fine-grained material which flowed downstream for some distance (VPP, 1859 - 60). From these figures it can be assumed that for the ten years during which this volume of puddling was maintained (1854 - 1864) over 5 700 000 m3 of gravels and sands and 17 200 000 m3 of fine-grained sludge had been discharged into and around Bendigo Creek. This was enough to cover an area of over 400 km2 to a depth of 5 cm. By 1859 the problems associated with the sheer volume of sludge being discharged were such that a Royal Commission was appointed to `Enquire into the Best Method of Removing the Sludge from the Gold Fields' (VPP, 1859 - 60). The goldfields referred to were those in the Bendigo area around the township of Sandhurst (now known as Bendigo). The Report of the Commission (VPP, 1859 - 60) stated that: `... inspection of the country bordering upon the course of the Bendigo Creek, to a distance of about fifty miles from Sandhurst . . . ' had revealed that the sludge had ' . . . filled up watercourses and flooded pasture lands . . . '. It also noted that ' . . . even on the plains, thirty or forty miles away from Sandhurst, where the sludge flows thin, and is relieved from its heavier particles, we found it baked into a perfect concrete, and in thicknesses varying up to two feet or more . . . '. The italics were used for emphasis in the original text. As it was considered unlikely that the physical evidence for such widespread inundation would have disappeared completely over the intervening 130 or so years, a project was initiated to locate any evidence of the inundation in the current landscape. If such evidence were to be found, then an estimate could be made of both its extent and its effects on the topography, drainage, and land-use of the inundated area. Extensive field work has determined that over 700 km2 to the north of Bendigo was inundated by the sludge. The area has not been uniformly covered, but has occasional `inliers' which have obviously escaped inundation by being slightly higher than the surrounding areas. Today the sludge is readily identified as a very fine-grained, hard-setting, concrete-like `capping' overlying a well-developed, well-structured, pedal horizon, or in some instances, the gravels and sands of a creek bed. The thickness of the sludge capping varies between a few centimetres and three metres (Peterson, 1996). The buried topography was gently undulating, in direct contrast with the almost unnatural flatness of

Jan 1, 1997

Thiess Dampier Mitsui's Moura-Mine is located in the south-eastern corner of Queensland's Bowen Basin, some 180 kms west of Gladstone. Current requirements of the open cut operation are to drill and blast 25 million cubic metres of overburden per year, consuming some 12,000 tonnes of explosive in order to meet the requirements of the mine's four operating draglines and one overburden shovel. By early 1985 it had become obvious that the existing drill and blast equipment and technology could not cope with the long-term needs of the open cut mining operation. Three 61R drills were in need of rebuilding or replacement. Bulk ANFO trucks working two shifts per day were unable to match the requirements of the four draglines dne to long travel distances, slow discharge rates and their inability to load water-resistant products into the increasing number of wet holes. This paper outlines the significant steps taken to introduce new equipment and technology and the resulting improvements in the mine's productivity and economics.

Jan 1, 1986