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By Clark GH

Batu Hijau is a porphyry copper-gold deposit located on Sumbawa Island in the western Banda Arc of Indonesia. The deposit has been evaluated from 54000m of drilling in 105 diamond drill holes over a surface area of 1.2km2 and to a depth of 1000m below surface (412m below sea level). A provisional plan is being evaluated to mine 642 million tonnes at an average grade of 0.61% Cu and 0.55g/t Au (variable cutoff) from an open pit in the higher grade portion of the resource. The deposit is associated with a caic-alkaline intrusive complex that was emplaced in a thick sequence of andesitic pyroclastic rocks. The oldest and most widespread intrusion is porphyritic to medium-grained, equigranular, quartz hornblende diorite. At Batu Hijau the western diorite contact zone was intruded by two phases of tonalite. The older tonalite is a stock increasing from 200m diameter at surface to 500m at sea level. It consists of quartz, plagioclase and hornblende phenocrysts set in a groundmass of similar composition. A younger tonalite intrudes the tonalite stock, quartz and plagioclase phenocrysts are more abundant and it has a finer groundmass than the older tonalite. Brecciation occurs near the older tonalite contacts but there are no breccia pipes or late-stage features such as pebbldykes or postmineralisation intrusive rocks.

Jan 1, 1995

The Banda arc, a U-shaped orogenic belt which separates oceanic crust of the Banda Sea from continental crust underlying the Australian- New Guinea shelf, has been interpreted to mark the convergent boundary between the northward-moving Indian Ocean- Australian plate and the Southeast Asian plate (Hamilton, 1979; von der Borch, 1979; Bowin et al., 1980). East of the island of Sumba (Fig. 1), the oceanic crust of the Indian Ocean has been completely subducted and Australian crust is now thrust under the Banda arc. Controversy has centered over the interpretation of the Timor trough as the surface location of subduction and the significance of the Savu Sea between Timor and Flores as either a forearc basin or the continuation of the Java trench (Karig et al., 1987). Two concentric island ridges, called the inner and outer Banda arcs (Hamilton, 1979), separate Australian continental crust from the oceanic crust of the Banda Sea (von der Borch, 1979) (Fig. 1). The inner arc is a typical volcanic island arc composed of calc-alkalic volcanic rocks of Neogene age, while older (Permian and younger) complexly deformed sedimentary and metamorphic rocks make up the outer arc. Timor is the largest and most extensively studied island of the outer arc and is separated from the inner arc by the Savu Sea. The triangular-shaped Savu Sea appears to be a complex forearc basin divided by a series of buried basement ridges (Karig et al., 1987). The outer, convex side of the Banda arc is followed by a major negative bathymetric feature known ne rho Timor trnnnh

Jan 1, 1987

By O K. Paki

A 14/12 millMAXTM pump was installed in the SAG1 grinding circuit as a trial replacement for the existing 12/10 Warman for performance comparison and in an attempt to overcome process difficulties. Krebs Engineers have developed the millMAXTM pump wet end to adapt to a variety of power frames. This system has been developed specifically for coarse material contained in mill discharge. SAG1 discharge screen undersize with a top size of 10 mm is collected in a flat bottom sump. Two 12/10 Warman pumps located on the same side of the sump, pump the screen undersize at 50 to 65 per cent solids to a distributor box which splits into two separate ball mill circuit sumps. One pump is installed towards the screen feed, while the other is towards the screen oversize discharge. The pump located towards the screen oversize discharge is prone to continual operating problems including pump bogging, high impeller and casing wear, and has consequently restricted SAG mill throughput. To rectify this pumping problem, it was decided to change-out the wet end of this pump with a millMAXTM. The design of the new pump enabled the wet end only to be retrofitted to the existing Warman pump frame, thus reducing change-over time. This was undertaken in the workshop under the supervision of a company representative where the pump, complete with bearing frame, new wet end, motor and base frame, was assembled. After installation of the millMAXTM pump during a SAG mill shutdown, performance indicators including motor power draw, sump level, and pump discharge pressure have been monitored. The trends indicate an increase in discharge pressure, low sump level, and low motor power draw. With the improved pumping efficiency there has been minimal pump bogging and no consequent SAG mill throughput restrictions. Pump wear rate has also decreased.

Jan 1, 2000

By J Tuma

Technical measurements are an integral part of research and development of new technical devices. Now they are also an integral part of production too, especially as a part of quality control systems. More new problems started with they applications up, like storing and following preservation of big data files. Many problems are also with processing of the measurement results, especially to be up to standards of ISO 9000 normative. It includes basic data about the measurement (structured data) and measurement outputs (huge data streams). Using database systems looks as good idea, because of structured measurement data and they processing. They were developed more concepts of database measurement system support during the research project MSM 272300012. It was decided to develop specialised measurement systems, on the base of experiments and experiences with they use in operating conditions. It proved to be wrong to develop general system, because of compound operating and long response of the system. And it is not possible to use these systems for mass production systems. The problem of data storing is not as easy to be answered, because of dependence on used technical devices. During realisation the measurement system for gearbox noise measurement are data stored to the database, because used analyser system PULSE (Brnel and Kjµr Co) is open structure and can cooperate with other software systems. Anyhow the data streams are not longer (after compression) than the Memo data type, in practical use increases the data file too fast (about hundreds MB daily). Therefore we must include a special supervisory system for administration and creating data files to the system. Nevertheless the used system MS-Access supports data files up to 1 GB, for practical application is better if the file size do not exceed the capacity of CD-ROM disc.

Jan 1, 2003

By Li G, Dean-Jones G. L, She T

Highwall mining is a specialised and largely automated mining method developed in the United States for the extraction of coal left under a shallow overburden cover after cessation of economical open cut mining operations. As the name indicates, coal is extracted from the seam exposed along a highwall by a remotely controlled continuous miner operating in a single unsupported opening and brought to the surface by a string of conveyor segments. The single entries are separated by coal .pillars and driven normal to the highwall, over areas where the thickness of cover and volume of recoverable coal is insufficient to allow or justify conventional underground mining. An additional highwall mining method is augering. The success of high wall mining operations depends significantly on geological features, notably the stability of the working roof, determined by the type and mechanical properties of the immediate roof strata. Stability of the ribs, absence of floor heave, faults and dykes are further important prerequisites for profitable highwall mining. The geometric relationship between the spatial attitudes of existing joint systems, the direction (azimuth) of the single entry opening and its vertical profile determine the unimpeded depth of penetration into the coal and thus its economic success. The mechanical implications of the lithological transition zone from a coal seam to either primary or original roof strata, compared to an interface between the coal seam and overlying strata, characterised by a sharp erosional boundary between coal and a secondary immediate roof stratum, are very significant. The compatibility between the response to mining by the geological system (floor-seam-roof) and the capability of the mining equipment to prevent the development of instability are essential requirements from a mechanical viewpoint. The minimisation of vibrations, very good horizon control, an ability to vary the profile of the opening, and the maintenance of consistently high advance and retreat rates, are also important aspects of profitable highwall mining.

Jan 1, 1995

The perception of the mining industry in the Australian community has changed considerably over the last four decades. This has been partly brought about by changing values and expectations of the Australian community as well as by global factors. The legal environment for the Australian mining industry has undergone significant changes. Among them, the High Court's Mabo decision which confirmed native title rights as part of the common law and environmental legal developments are dealt with particularly. It is suggested that the Australian legal environment is not necessarily the prime cause for Australian mining companies taking their investment off shore. This is a summary on how native title impacts on land tenements and some of the major issues that emerged since the `Mabo decision' and the Native Title Act 1993 are discussed. Environmental legal developments have resulted in liability facing directors and senior management in compliance matters .and in operating mining and other businesses because of changes in community expectations. In the next decade it is suggested there will be many drivers for more changes in the legal environment. Some of these are touched on including the changing roles of the Commonwealth and State Governments, the High Court as -law-makers and the changing relationships with indigenous people in Australia and in overseas countries. The changing legal environment for mining demands a national approach in many areas on the proposition that resource based industries are part of a national industry. The uniform law approach among the States has been taking place but this needs to further. An appropriate task force should be forward to review the entire legal structure and regulations affecting mining on a national rather than a State basis . The mining industry will need to work with expectations of a changing community which have powerful, but sometimes contradictory, interest groups.

Jan 1, 1997

By Pollmans GJ, Hoberg H, Schneider FU

The Institute of Mineral Processing at Aachen University of Technology has been engaged in fine and ultrafine comminution for several years. Former investigations had been dealing with the mechanical activation with the aim of increasing the solubility of highly resistant oxides such as tantalite and niobite while research on the product of ultrafine powders is of major importance at the moment. Materials of that kind are of increasing interest in the production of extremely resistant ceramics, in the development of new raw materials, in powder metallurgy and in the production of fillers (extender pigments) and pigments. The creation of ultrafine powders is difficult and very expensive. They can be produced by means of condensation or dispersion methods. One important method of dispersion is mechanical comminution. Due to long and intensive research and development all over the world important advances have been achieved but still a great number of questions and problems occur especially in producing materials of submicron and nanometer grain sizes which could be answered or solved only insufficiently up to now. These mentioned difficulties refer especially to: ò the required energy input into the feed material, ò the forming of strong agglomerates and wall stickings, ò the required product qualities, and ò the entire and reliable characterisation of the products. Basic investigation aim to clarify the micro and macro processes of ultrafine grinding and work towards solutions to the difficulties mentioned above. The aim of the Institute's research is the development of a new grinding device for producing ultrafine powders. First results of a laboratory scale mill of that type will be presented in this paper.

Jan 1, 1993

By H Zhang, Y Wang, S Sukenaga, H W. Ni, H Shibata, W Z. Mu

The crystallisation behaviour of low melting point CaO-SiO2-Al2O3-MgO inclusions greatly affect the deformability of inclusions during the rolling process. The crystallisation characteristics of CaO-SiO2- Al2O3-MgO melts representing the oxide inclusions in Si-Mn killed steel were systematically investigated. The effect of Al2O3 and MgO contents on the crystallisation change were analysed under a fixed CaO/SiO2 in the complex inclusions. The continuous-cooling-transformation (CCT) and time-temperature-transformation (TTT) experiments were conducted. The results showed that the increase of MgO content increases the crystallisation ability of CaO-SiO2-Al2O3-MgO inclusions, while the increase of Al2O3 content has the opposite effect. The viscosity, liquidus temperature of oxide melt and also the initial crystallisation potential might be the reasons for the change in crystallisation behaviour. Also, the crystallisation activation energy could semi-quantitatively characterise the crystal growth during the crystallisation of inclusions. To obtain low melting point plasticized CaO-SiO2-Al2O3-MgO (CaO/SiO2=1) system inclusions, the Al2O3 content of the system needs to be controlled larger than 15 wt per cent and the MgO content should be kept at a small amount.

Aug 21, 2024

The seemingly insatiable world demand for mineral and energy products is continuously pushing out the frontiers of exploration and development in countries around the Pacific Rim.

Jan 1, 1990

By I Haine, J Penm, T Waring

During 1999 there was a considerable turnaround in world prices for most minerals and energy commodities, except for the bulk commodities (coal and iron ore). The main reasons for this turnaround were: improved prospects in demand for most minerals and energy commodities in the Asian region following a return to both economic and industrial production growth in key economies in that region; continued moderate growth in demand in Europe and North America; substantial production cutbacks in a range of minerals and energy industries; effective reductions in the supply of oil by OPEC nations; and an announcement by European central banks that they would cap the amount of gold they sell and loan in the next five years. Most of these influences are expected to be sustained into the first years of the new millennium. In 2000, with exception of coal, average world prices of minerals and metals are forecast to rise significantly. Gross domestic product and industrial production is expected to grow in some European countries and most Asian countries in 2000 and, with moderate growth expected to be sustained in the United States, demand for minerals and energy is expected to increase. AustraliaÆs main bulk commodities, iron ore and coal, saw prices set for 1999 - 2000 at substantially lower levels in negotiations in early-1999. Double digit price cuts were locked in. However, similar falls appear to have been avoided for coal in Japanese Fiscal Year 2001, while increases of between four and six per cent were achieved for iron ore. Forecast modest recovery in economic growth in Japan and increasing demand elsewhere in Asia are expected to lead to tighter market conditions in 2000. Beyond 2000, world minerals and energy markets will be influenced by the expected robust global supply responses of minerals and energy companies, against a background of sustained economic growth and industrial production growth in major consuming countries. Over the medium-term, a return to declining real prices which have been evident for most commodities in the recent past, is expected as exploration, mining and processing technological change and associated productivity growth continues to reduce industry costs. While lower rates of exploration and mining investment in Australia between 1998 and 2000 will modestly constrain the rate of future industry expansion, Australia remains an important contributor to expected growth in global minerals supply over the medium-term. Australian mine production is forecast to grow between 1999 - 2000 and 2004 - 05, boosted by production from recently commissioned mines and minerals processing facilities and comissioning of other projects at advanced stages of planning.

Jan 1, 2000

A general approach to the analysis of processing technology is presented using the concepts of Process Aims, Process Characteris- tics and Process Costs. From an examination of the processes used in extractive metallurgy a hierarchy of process aims is identified, these aims are separation, compound formation,, metal production and metal purification. The application of this methodology to process flowsheet development is described.

Jan 1, 1984

By A Turichshev

The synthetic rock mass (SRM) approach for modelling jointed and veined rock has been at the forefront of caving geomechanics research for years. A well-constructed and calibrated SRM model can capture the full rock behaviour at a macroscopic scale. Traditionally, SRM technology employed bonded particle models (BPM) due to their ability to model rock’s response to loading without prior specification of behaviour. The SRM modelling process requires the BPM to simulate intact rock and the subsequent introduction of fractures or veins by changing bonding characteristics between the particles. However, bonded particle materials have difficulty reproducing both the compressive and tensile strengths of intact rock. This and other limitations of BPM have been the driving force in exploring the potential of grain-based (2D) and bonded block (3D) models (BBM).This paper reports on recent work exploring the applicability of both BPMs and BBMs in 3D to the modelling of intact rock. The advantages and limitations of both BPMs and BBMs are addressed based on the results of numerical simulations using the PFC3D and 3DEC distinct element codes. The preliminary results suggest that BBMs are better suited for simulating intact rock behaviour than BPMs. Ongoing work aims to better qualify the applicability of BBMs under different conditions. This has significant implications for our understanding of rock mass behaviour in a caving environment.CITATION:Turichshev, A and Hadjigeorgiou, J, 2016. Simulating intact rock behaviour using bonded particle and bonded block models, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 453–460 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Opinions vary widely within the community on what are legitimate environmental social respon- sibilities. The extreme conservationists see the responsibility as the total preservation of the natural environment achieved by opposition to all forms of industrial development that would disturb it. The `growth-at-any-price men' consider it more important to stimulate economic growth, develop new industries, and maximize profit letting the environment take care of itself: within this wide spectrum of concern are the middle-of- the-road men, part of the vast majority, fully aware of the need to compromise to achieve a satisfactory economic growth rate whilst pre- serving to the greatest extent practicable the con- ditions upon which we depend for a balanced self-perpetuating existence. Environmental change is not new. It is the inevitable accompaniment of human activity. Plato wrote in the 5th Century B.C.* of the devastating changes wrought by man and his animals on the ancient world of the Mediter- ranean. Down through the ages rural development to *The Dialogues of Plato: `What are now her moun- tains were lofty, soil-clad hills; her so-called shingle plains of the present day were full of rich soil; and her mountains were heavily afforested-a fact of which there are still visible traces. There are moun- tains in Attica which can now keep nothing but bees, but which were clothed, not so very long ago, with fine trees producing timber suitable for roofing the largest buildings; and roofs hewn from the timber are still in existence. There were also many lofty cultivated trees, while the country produced bound- less pasture for cattle. The annual rainfall was not lost, as it is at present, through being allowed to flow over the denuded surface into the sea, but was received by the country, in all its abundance, into her bosom, where she stored it in her impervious potter's earth and so was able to discharge the drain- age of the heights into the hollows in the form of perennial springs and rivers throughout the land.' provide the necessities of life for expanding populations has required the destruction of vast areas of forest. Industrial activities over the last 200 years have discharged enormous quantities of solid wastes, liquid and gaseous effluents that were environmental pollutants of the worst kind. Urbanization has drawn people, their machines, and industries into vast concentrations aggregat- ing the environmentally bad effects of each to the extent that there is evidence that through thermal pollution these large urban industrial complexes nrp nffPrtina raainnnl rlimnta.c

Jan 1, 1978

A computer programming language known as GPSS is described and possible applications for the mining engineer are presented. The language is continually being upgraded with improved versions appearing about every three years. The tremendous power of the language is considered by comparing it with standard engineering programming languages, such as Fortran or Basic. Sample problems that can be solved using the language are indicated. The advantages and disadvantages of the languages are also discussed.

Jan 1, 1987

In-stope long hole drilling (face parallel drilling) is a new technology currently being applied to shallow dipping (

Jan 1, 2003

The environment under discussion is that of the sandy coastal plain and adjacent offshore sandy islands. The environment is the result of natural forces of the past which moulded it. Only very recently have men and machines participated in this moulding. The future of the environment - the changes which it must undergo - is in the hands of natural forces with, presumably, man's continued participation. In essence, we are concerned with the forces operating on a mass of sand.

Jan 1, 1971

For the purposes of this paper the Newcastle Coalfield is considered to be that 35 km wide rectangular tract of country west of a line running 45 km along the coast, south from Newcastle.

Jan 1, 1993

By Miller B

General experience with improvement programs in the mining industry has been that, after some initial success, performance tends to deteriorate back to pre-improvement program level in a relatively short time after the spotlight is switched off.

Jan 1, 1998

In-pit crushing systems have been known in the mining industry for many decades. The question whether in-pit crushing is a viable option has often been asked. More than 200 mobile and semi mobile crushing systems have been installed worldwide at various locations and applications. Economic pressures have forced mine operators to reconsider the use of a conventional truck-shovel operation and have contributed enormously to the development of in-pit crushing and conveying systems. The in-pit crushing concepts have varying mobility capabilities. These range from fixed, stationary crushing plants to semi-mobile and fully mobile crushing plants. All these systems are operated in connection with a conveying system. In general in-pit crushing systems have technical and economical cost advantages over truck-shovel operation, particularly as mine capacities increase and mines become deeper. The integration of an in-pit crushing system represents a significant up-front capital investment and the mine is only able to depreciate the capital investment over a sufficient mine life including plant capacity to realise the benefit of the much lower operating cost.

Jan 1, 2003

In order to do the discharge estimation better, it is valuable to find out appropriate formulas for estimating discharge in various pits, based on accumulating data, summarizing discharge patterns applying optimum seeking method and principle, by seeking redical exponent with help of the method of exhaustion, as well as testing and making statistics, in accordance with the quality standards established by our practical experience.

Jan 1, 1988