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By Cutafani M, Lama R

An approach to combatting abnormal roof control conditions in underground coal mines is outlined. Support techniques available are discussed along with the methods available to be adopted in different situations. Properties of materials available presently are tabulated together with the conditions of their Application.

Jan 1, 1988

ABSTRACT' Mainland Papua New Guinea is formed of a microcontinental / island arc system (?Eocene - latest Oligocene Sepic arc) which in Middle to Late Miocene times was obducted over the northward- moving Australian plate. The sedimentary and volcanic units of this system form part of the Wogamush Group (Aure beds, Mena beds, Omaura Formation, Movi beds, Wogamush beds, Wogamush Formation. Nansananka Conglomerate and other correlates in- eluding cale-alkaline volcanics and carbonate beds). This Sepic event was followed in Pliocene-Present times by the obduction of the Finisterre-Adelbert-Oenake fore-arc or possibly oceanic plateau. Obduction of the Sepic arc produced crustal thickening

Jan 1, 1997

The weathering of different types of base metal deposits in the semi-arid environment of the Lachlan Fold Belt of western New South Wales affects the geochemistry of outcropping ironstones (gossans) and derived soils. W eathering of the pyrite- and pyrrhotite-rich mineralisation at the Elura Zn-Pb-Ag deposit leads to highly acidic conditions and strong depletion of Cd and Zn throughout the profile. There are local attainments of high concentrations of Ag, As, Ba, Cu, Hg, Pb, Sb and Sn in the profile and As, Ba, Pb and Sb are still highly anomalous in surficial material (ironstone and soil). However, at Parkers Hill, in the Mineral Hill Field, the primary Zn-Pb mineralisation is pyrite-poor and so weathering is not as acidic as at Elura. Thus, although Ag, As, Cd, Cu, Sb and Zn may be concentrated at various levels in the Parkers Hill weathering profile, Cu and Zn (as well as As, Pb and Sb) are retained in surficial ironstones in essentially the same abundances as in primary mineralisation. Thus, variations in the suite of geochemical indicators present in ironstones and residual soils are likely to reflect differences in the original mineralogy and the degree of acidity produced during the weathering of base metal mineralisation. Hence, an understanding of weathering processes is necessary to fully interpret exploration geochemical data.

Jan 1, 2004

Pyrite is one of the principal Au-bearing minerals in refractory gold ores. Significantly high Au concentrations of up to 5200 ppm are present in pyrite. Pyrite hosting high levels of Au is also enriched in As. Pyrite as an unwanted mineral ends up in wastes and constitutes one of the primary sources of As in the mining and metallurgical wastes. Arsenic can be readily released to the environment due to rapid oxidative dissolution of the host pyrite under atmospheric conditions. In order to determine the form and occurrence of arsenic in pyrite, micro-X-ray absorption fine-structure spectroscopy (XAFS) spectra were collected from a range of arsenical pyrite grains having different morphologies and a range of arsenic and gold concentrations. All the pyrite grains are characterised by the dominant edge aligned with As-1 valence state. In pyrite, arsenic atoms substitute for S atoms that are in six-fold coordination about each Fe atom. XAFS data suggest that As atoms occur in clusters within the pyrite structure. In addition to As-1, fine-grained, inclusion-rich and framboidal-type pyrite grains have a second As species at ~11 875 eV corresponding to As5+. This As5+ species in pyrite is highly variable and attributed to the oxidation of arsenic exposed on the surfaces of pyrite.

Jan 1, 2008

By Boyce WH

Earthquakes are the most frightening and devastating natural phenomena known to mankind. They strike without warning and their consequences can be disastrous in terms of the toll of human life, financial crises related to the damage or destruction of man-made structures and the social and economic effects on a wide spectrum of the affected communities in the aftermath of the event. Such situations can be widely attested to by most areas around the Pacific Rim. Indeed, the threat of earthquakes is always imminent because of the geological-tectonic nature of the region as manifested by past experiences. It is patently obvious that earthquake occurrences are not only a geological hazard but also pose a serious social danger. When one considers the 19 September 1985 Mexico (Michoacan) earthquake (Mitchell at al., 1986), the necessity of continuing research is of paramount importance. An estimation . of earthquake risk encompasses both qualitative and quantitative aspects and demands a multidisciplinary research effort integrating seismology, tectonics, geology, enginering, sociology, economics, insurance and governmental policies (Bolt, 1978; Booth, 1984). These roles in mitigating such a hazard have been aptly discussed by Press (1985). A series of discussion papers based on an intergovernmental conference covering the whole scenario were published by UNESCO (1978). A comprehensive case history was provided through a workshop on the 1886

Jan 1, 1987

The Committee for Mineral Reserves International Reporting Standards (CRIRSCO) was formed in 1994 to promote development and adoption of international standards for estimation and reporting of exploration results, mineral resources and mineral reserves. The CRIRSCO standards have been accepted by most mining companies and professional societies worldwide. Market regulators from Australia, South Africa and Canada require that these standards be followed when releasing public information. Among these requirements is the use of specific definitions for what constitutes exploration results, mineral resources and mineral reserves. If such information is publicly disclosed in must be estimated by a Competent or Qualified Person. In the United States of America, public disclosures are regulated by the US Securities and Exchange Commission. The SEC does not recognise the CRIRSCO guidelines, and some of the SEC requirements for public release of information are materially different from those applicable in other countries. The CRIRSCO definitions and the Competent Person requirements are reviewed and compared with those of the SEC. The organisation of the SEC and its rule making process are briefly discussed. Ongoing efforts to bring the US regulatory requirements closer to those applicable in other countries are presented, as well as other activities that CRIRSCO is entertaining with the United Nations, the International Accounting Standard Board and other international organisations to reach the objective of worldwide standardisation of reporting procedures.

Jan 1, 2006

By C M. Hill

This paper aims to provide a brief overview of the Australian Coal Bed Methane (CBM) industry and more importantly the challenges to sustainable management of the industryÆs by-product, groundwater. In a country where water is scarce and having gone through one of the worst recorded droughts it is vital that this important industry be seen to be managing water in a responsible manner with the greatest environmental and social benefit. Benefits of the water from CBM wells can be enhanced through treatment to produce potable water for domestic or stock purposes, water for irrigation or aquaculture or lower quality or untreated water for industrial or mining purposes. Other options are re-injection of raw water or waste from the treatment processes or discharge to surface waterways. The critical change and difference between CBM projects and traditional oil and gas operations should be that where possible water is no longer disposed of via evaporation ponds with the dual legacy of waste of the water resource and an environmental contamination problem with the remaining salt and brine product.

Jan 1, 2003

An intensely sheared and mineralisedIzone occurs in the Quartz Dolerite Greenstone (or Younger Greenstone) mass on, the western limb of the Kalgoorlie Syncline. This zone comprises the western part of the Golden Mile and has produced the greater part of the 33,000,000 ounces of gold produced to date from the main mining belts. A study of.th e general geological and structural features gives rise to the expectation that the lode shear system,will continue southward on a pitch similar to that of the maln syncline whose axial plane may be referred to as the "Boulder Dyke". Although payable ore has recently been found further south than previously, the expectation of large quantities extending southward from the present mining areas is Problematical.'

Jan 1, 1964

This paper deals with the evolution of present mechanised declining and orebody development practices at Kambalda, since their inception in 1969. Eight separate decline accesses have been established over the past eighteen years and to date some 175 kilometres of declining and lateral development has been achieved utilizing a wide range of mechanised development and mucking units. Improvements in-the range of equipment available, functionalization of the develop- ment tasks and the resultant changes to piecework contract structuring have all contributed to the improved performances achieved in this concept of mine development. Even though numerous development advance rate records have been established at Kambalda, an ongoing evaluation of changes to both drilling and mucking units is underway to further improve these development performance rates.

Jan 1, 1987

By N Vagias, R Shaw, M Coghill, W Easman

Rio Tinto Technology and the Rio Tinto Foundation for a Sustainable Minerals Industry have funded the development of a practical floating module that can reduce water losses through evaporation from water dams at mining and mineral processing facilities by about 75 per cent. The modules, which are also suitable for use by farmers and communities, were designed for easy deployment, to allow the water to æbreatheÆ, harvest rainfall and resist wind speeds of more than 100 km/h. A large-scale demonstration trial will be conducted at the Northparkes Mine, located near Parkes (New South Wales, Australia). The objective of the trial is to demonstrate to Rio Tinto business units, community, farming and government groups the moduleÆs operating costs and water saving potential.

Jan 1, 2006

Pajingo Gold Mine Pty. Ltd. is a subsidiary of its United States of America parent the Battle Mountain Gold Company. Battle Mountain Gold Company was created in August 1985 as a spin-off of the United States of America Pennzoil Company's gold interests.Pajingo Gold Mine Pty. Ltd. currently has its headquarters and base for operations located in Townsville, Queensland. The Company's main current activities are the exploration and evaluation of the Pajingo Gold Property situated some 50 kilometres south-east of Charters Towers and in the northern Drummond Basin.The discovery of the Pajingo gold mineralisation by the Company was the indirect result of a regional program established to evaluate Carboniferous age volcanic plugs in north Queensland for gold mineralisation.

Jan 1, 1986

By McNabb K. E

Significant coal reserves in New South Wales lie under areas with steep topography such as valley slopes and cliffs. Subsidence predictions are difficult to make for these locations as existing empirical databases cannot cover all permutations of topography and mining geometry. Two dimensional numerical model alternatives are of limited applicability. Consequently a novel three-dimensional numerical model is developed including the detailed panel layout, realistic rock mass properties including the full stratigraphy, goaf behaviour and actual surface topography. Model results show the same trends as subsidence measurements from Baal Bone Colliery in the Western Coalfield of New South Wales.

Jan 1, 1992

Wire rope, when used for hoisting on a mine is the weak- est and most vulnerable unit in the most expensive'-group of installations or! the mine. With the introduction' of hoisting on the S1Koepe"' sheave, a new technique was-established. This innovation brought with it the certain- advantages which long had been recognised and which are being developed further. For many years, drum winders of many types had been the sole means by which ore had been hauled from mines. This type of winder, with its capacity for rope storage on the drum, permitted mine operating personnel to cut short lengths from

Jan 1, 1964

By R Balusu

This paper provides an overview of computational fluid dynamics (CFD) modelling capability developed by CSIRO with the aim of improving the knowledge of flow migration dynamics within longwall goaf areas. The CFD models can be used to study the ingress of oxygen into the goaf in different ventilation scenarios and goaf drainage arrangements. This approach not only helps the design of effective gas control strategies but also the management of spontaneous combustion risk in the goaf. Innovative goaf inertisation strategies have been developed and implemented during longwall sealing operations. Work is continuing to develop general guidelines of proactive goaf inertisation strategies to suppress the development of spontaneous heating behind active longwall faces.

Jan 1, 2005

Electronic detonators bring a fundamental and radical change to the potential of rockbreaking operations. The immense technical challenge of safely merging electronic systems with explosives has been largely overcome, but a surprisingly difficult obstacle has been to convert users to the much more capable electronic systems, in routine as opposed to exotic applications. Unit cost is probably the main point of resistance. For years papers have confirmed significant improvements in blasting results, feeding through to enhanced bottom line value for the whole operation: much reduced environmental impact, and improved control over fragmentation, muckpile shape and overbreak. In Africa, a number of operations have been employing the technology for sufficient time to see enduring improvements in throughput, control and cost structure, and these improvements have fed through to the planning process: both the cost and the benefits are part of the plan. This has essentially rendered very unattractive the option of reverting to pyrotechnic systems and incurring the penalties previously unseen but now understood to be avoidable. Examples given are of improved throughput at opencast and underground mines, and greatly extended life at an urban quarry. The general experience of management in implementing the technology is that it over-delivers: adopted to solve one particular problem, significant other issues are also addressed. These extra benefits were quite logical, but not at all obvious prior to implementation. Exploring this reality is essential for harvesting the benefits of the technology sooner rather than later.

Jan 1, 2004

By Winter W, Steele DA, Trudu AG, Gray CM

The Luzon arc extends for about 900 km from Taiwan to the island of Mindoro (central Philippines); in this area late Tertiary to Recent volcanism is considered to be the result of eastward subduction along the Manila Trench. The arc is composed of five segments, all of which have individual characteristics with respect to tectonic setting and magma chemistry (Defant et al., 1989). From the north to the south these are (Fig. 1): (1) the eastern Coast Ranges of Taiwan and the islands Lan-Hsu and Lu-Tao (Taiwan Segment), (2) the islands off the north coast of Luzon (Babuyan Segment), (3) the Northern Luzon Segment, (4) the Bataan Segment, and (5) the Mindoro Segment. Defant et al. (1988) suggest that the Bataan and Mindoro segments of the arc, both of which are characterized by different isotopic compositions and levels of large ion lithophile element (LILE) enrichment in the lavas, are separated by a 'pull-apart' zone, the Macolod Corridor.We are currently studying the mineralogy and petrochemistry of Late-Miocene to Pliocene volcanism in the Northern Luzon Segment (NLS), which comprises the geographic area of the Cordillera Central. This area has so far received limited attention, inspite of its wealth of porphyry copper, skarn and epithermal gold deposits. In this contribution we report the first results of our study of igneous rocks from the Mankayan Mineral District (MMD) which is located in the centre of the arc segment under consideration.

Jan 1, 1990

Australasian mining companies expect a high standard of professionalism from their metals exploration teams. They also have, increasingly, a global perspective, employing explorationists of diverse cultural backgrounds and operating in diverse environments. Human resource development (HRD) of these professional explorationists needs to address all personal facets of functioning independently and interdependently in a modem working culture, as well as the needed technical competency. Creation of a learning organisation to promote this development is critical. Organisational consultants can support managers and supervisors as mentors facing the wide spectrum of development required by the explorationists; mentorship and guidance counselling can then complement training in the maturing of professionals from technical competence to professional independence and interdependence. Empowerment and clearly stated expectations are keys by which professionals can learn efficiently and effectively.

Jan 1, 1996

By C P. Kramers

The need to provide a sufficient quality and quantity of backfill continues to increase in South Africa, particularly as related to the increasing depth of mining. More and more applications require well designed fill systems either as classified or cemented backfill, and in some applications even tailings/aggregate based backfills. The paper discusses developments in backfill technology in South Africa with special emphasis on reliable system designs and operations, particularly as related to the preparation and hydraulic transportation aspects. Approaches for the alleviation of previous problems associated with premature pipe failures in vertical shaft columns for the distribution of tailings based backfills are discussed. Resulting from CSIRÆs developmental work, reliable full-flow systems, which can operate at low system pressures, have become a common practice, provided that backfill flowrates and internal pipe sizes are well matched. This aspect is reviewed. With regard to the tailings/aggregate based backfills the paper reviews some of the results of comprehensive in situ monitoring and the development of such systems. It is shown that a thorough understanding of the effects of aggregate top size, fines content and slurry relative density is required in order to ensure the restartability of temporarily shut-down pipelines. Some innovative technologies for the comminution of development waste underground to yield aggregate products potentially suitable or hydraulic transportation and backfilling, are briefly discussed.

Jan 1, 1998

IN presenting the following short paper the writer hopes to illustrate some uses of explosives in industrial work under conditions different to those prevailing on mining fields. This paper is based on experience gained at the Newcastle steel works of the Broken Hill Proprietary Company Limited. The management had decided that as soon as No. 2 blast furnace which is of an improved design was ready to be put into commission, No. 1 blast furpace was to be dismantled and reconstructed to a similar design to No. 2 furnace. This reconstruction entailed the removal of the brick lining of the furnace shaft, and, also the removal and disposal of the,"salamander" and hearth-lining. For the information of members who may possibly be unacquainted with the term "salamander," it might be explained that this term is used by iron metallurgists to denote the mass of iron and slag formed at the- bottom of the furnace, whilst in commission.The method of disposal depends upon the size and nature of the salamander, and in the case under review it was decided to bury it below the hearth of the 'furnace' to be reconstructed. A passage-way was made in the concrete walls of the cast house, and the sand-filling of the cast house removed sufficiently to allow of the concrete foundations of the furnace being reached. This passage-way was extended until the hearth was encountered. The next operation was the removal of the hearth-lining below the salamander. The removal of the concrete was not difficult...

Jan 1, 1921

By Pollard D. M

The BHAS copper-lead matte leach process, developed in Port Pirie, South Australia, has been in operation on a commercial scale since 1984. This process is one of many developed in the past decade to recover copper via the hydrometallurgical route. In essence, the process involves a single stage agitative leach of 100% -75um matte in an acid chloride-sulphate lixiviant with gaseous oxygen as oxidant. The leach temperature is controlled at 85¦C to assist with reaction kinetics. After leaching, divalent copper is recovered from solution via a conventional solvent extraction/electrowinning circuit to yield cathode copper for sale The BHAS matte leach process has several unique characteristics cf. other commercial oxidative acid leach processes. These include i) the use of gaseous 02 as oxidant ii) H2SO4 addition as make up acid iii) Relatively low chloride ion addition (30 g/1) For this reason, extensive work was carried out into the optimization of leaching by Meadows (1985). Variables investigated included ò Oxygen flow-rate ò Agitation intensity ò Leach temperature ò Free acidity ò Chloride ion concentration ò Matte particle size The current work was conducted to determine the effect of cooling rate, and hence mineralogy, on the leaching characteristics.

Jan 1, 1989