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By Finlayson E, Hilyard D, Francis G

Papua New Guinea's mainland is dominated by a foreland thrust belt, which can be divided into two zones. The "body" zone is floored by Palaeozoic granites and metamorphics of the Fly Platform (Tasman Orogen). Underlying the "tail" zone is Papuan Plateau, rifted from the Tasman Orogen during Coral Sea spreading, and believed to underlie the Papuan Peninsula and Papuan Islands region (D'Entrecasteaux, Woodlark, Misima, Sudest, and Rossel Islands). Thrusting began in the Miocene and continues today in the crust below the "body" zone. The youngest known thrusted rocks in the "tail" zone are Pliocene in age. Recognition of foreland thrusting has major implications for petroleum prospectivity of the Papuan and North New Guinea Basins, mineral exploration prospectivity, and geological terrane identification in PNG.

Jan 1, 1987

By R Austerberry, S Green

The discovery of the Cuffley Lode at Mandalay Resources Costerfield Operations provided an opportunity to extend mine life via mining the offset depth extension of the previously worked Alison Mine. Access from the existing Augusta Mine placed the initial Cuffley underground workings at approximately 250 metres depth from surface. As the new orebody transitioned towards production, a secondary means of egress needed to be established. The depth of the initial capital development presented a challenge in establishing a secondary means of egress that could be confidently relied on. The availability of land to locate a surface shaft collar further reduced available options and geotechnical drilling further limited suitable shaft locations. Time limiting factors such as permitting and having a secondary means of egress in as soon as possible, further highlighted that an innovative secondary means of egress was needed. A consideration of using an emergency gig lowered by a suitable sized crane supplied by an external crane contractor was investigated and found to be a suitable outcome. This Emergency Gig was deployed via the Cuffley Return Air Raise. When trialled, the emergency gig was found to provide a reliable, repeatable extraction method with an acceptable level of risk. Issues discovered during such trials further improved the process to a point where this extraction method became the adopted secondary means of egress for additional lodes that existed at depth. When assessing possible methods of secondary means of egress, the use of a third-party crane and custom designed and fabricated emergency gig should not be discounted. Where a crane can be sourced within an acceptable timeframe, the emergency gig extraction method provides a reliable safe and cost-effective means of secondary means of egress, especially when multiple shafts are to be developed. Local laws may negate the ability to employ such a system, although it is believed with good communication and well-constructed risk assessments, this system can be safely deployed.

Mar 15, 2021

A combination of new radiometric age dates, local field relationships and the regional tectonic history indicate that the low sulphidation, fault breccia-hosted, epithermal gold-silver mineralisation at Umuna is related to continental rifting processes rather than subduction induced deformation and magmatism. K-Ar and Ar-Ar age dating of secondary sericite associated with the gold-silver mineralisation indicates that the alteration crystallised between 4.0 and 3.2 Ma, whereas relative age relationships and SHRIMP II U-Pb dating of the abundant Boiou porphyry intrusions on Misima confirm that the calc-alkaline plutonism is significantly older (8.1 f 0.4 Ma) and related to a different tectonothermal event. The Woodlark Basin sea floor spreading centre occurs to the north of Misima and has continued to propagate westwards, into the continental basement of the Papuan Peninsular, since the end of the Miocene. The westernmost tip of sea floor spreading centre is presently to the east of the D'Entrecasteaux Islands but would have been to the east of Misima roughly 4 Ma. Many of the young tectonothermal features in the D'Entrecasteaux Islands (hydrothermal activity and associated epithermal mineralisation, metamorphic core complex exhumation, detachment faulting, peralkaline volcanism, half graben type basin formation) can be attributed to major extensional deformation ahead of the propagating rift system. Similar tectonothermal features on Misima are temporally associated with the epithermal gold-silver mineralisation at Umuna, suggesting that the D'Entrecasteaux Islands are a modern day tectonic analogue for Misima at the time of precious metal mobility and deposition. The rapid exhumation of high grade metamorphic rocks and localised

Jan 1, 1997

As this district is so far distant from the other mining centres and its mode of approach so circuitous, I am afraid that many residents of other portions of the Commonwealth never think of paying this" Australia's Silver City" a visit, to learn personally the many and various lessons everywhere available, and to become familiar with the really wonderful and interesting features and deposits (which pature has so lavishly bestowed in the mineralogical world) yet seemed to almost ignore or overlook when disposing of topogr,aphical beauties of landscape and vegetation) unless professional or business duties require their presence here. So it is to those whose life is necessarily spent in other parts of the States where they answer their call of duty, and yet feel an interest, either for business or other reasons, that my paper is specially addressed and prepared, and for that reason I witl endeavour to make my remarks more of an explanatory than a dictatorial nature. I feel sure that there. are many members of our Institute who are much more familiar, and have had many more years' experience in the various methods of timbering, filling, and ore extraction, etc., than myself, but I hope that over I6 years' experience in connection with mines and engineering works, the last six of which have been spent in Broken Hill, where, I have been very closely connected.

Jan 1, 1903

By Hoppe AJ

Drilling and shooting techniques at Moura open-cut have evolved over a period of 16 years and are the result of hard earned experience combined with established practices and consul- tation with professional services. The wide range of overburden types encoun- ted in the field requires varying methods to achieve the best results at all times. Safe working conditions for the employees and protection of mining equipment is of para- mount importance and close liaison is maintain- ed with the Department of Mines Queensland to keep abreast with changing legislation. Drill patterns, charging profiles, types of explosives and ultimate results are des- cribed in detail along with a resume of equip- ment. Costs of drilling, labour and explosives are also analysed with a total of approximately 20c per cubic metre of shot ground. Future developments and improvements to facilities are also outlined.

Jan 1, 1978

By Snowden C. T

B Lens Main is a scheelite orebody with an average dip of approximately 15¦ and thickness ranging from 1.5 to 6.0 m. The orebody is overlain by a banded section of ore and waste which tends to slab off if left unsupported. It was originally planned to mine a large portion of this orebody by room and pillar methods, with existing diesel trackless equipment. This, however, proved unsuitable for a number of reasons and the smaller scale method of slot stoping with hand machines and scrapers was employed. The following major problems were encountered. 1. The method was new to the mine and the work force, and had to be commenced quickly using existing or easily obtainable equipment. This is gradually being overcome by training, modification of procedures and introduction of more suitable equipment. 2. The slabbing from the hanging wall had to be controlled, either by support or by mining this low grade section and accepting the resultant dilution. This has been approached in a number of ways, depending on conditions and the method will have to be further modified as different conditions are encountered in new areas.

Jan 1, 1977

By Christie AB, Bull VH

The geological environments of gold deposits are reviewed in relation to the strong resurgence in exploration for gold since 1979. The resurgence is due mainly to New Zealand's geological endowment with gold and its history as a gold producer. Major past production was from Cenozoic placers of Otago and Westland, late Cenozoic epithermal deposits of the Hauraki Goldfield, and the respective Paleozoic and Mesozoic lode deposits of the Reefton and Otago Goldfields. These same geological environments are the targets of current exploration, mainly in extensions of previously mined deposits. On the Westland and Otago Goldfields alluvial and fluvioglacial gravel placers, mainly representing lateral and depth extensions of previously worked ground, are being mined and prospected. Gold production in 1984 was exclusively from these deposits, and the development of mobile concentration plants has resulted in a great increase in mining activity. Mineralised zones adjacent to previously mined lodes in the Hauraki Goldfield, Reefton Goldfield, and at Macraes Flat (Otago Goldfield) are being intensively explored. At Waihi (Hauraki), an open-pittable resource of about 10 million tonnes of ore has recently been delineated. Some new deposit types and little explored environments are also receiving attention. They include: gold-sulphide quartz veins hosted in an alkaline granite dike in west Nelson; hot spring type gold deposits in fossil geothermal (epithermal) systems of Northland, the Hauraki Goldfield and the Taupo Volcanic Zone; and marine placers off the West Coast where an area of auriferous gravels has been outlined near Hokitika. There is potential in known deposits and prospects currently being evaluated for a large increase in gold production by the early 1990s.

Jan 1, 1986

By L M. Foster, J R. Kellett, G A. McMah

The Great Artesian Basin (GAB) contains one of the largest reserves of fresh water in the world. The volume in storage is enormous, being estimated at nearly 65 000 million megalitres (ML). Development of this resource, dominantly for the pastoral industry, began in the late-1800s and quickly accelerated. With exploitation of the resource, artesian pressures declined almost as rapidly. This loss of head is a result of the total discharge from the basin and much of this discharge is waste of water. The waste through uncontrolled bores and inefficient distribution systems still amounts to about 75 per cent of all discharge. However, the volume in storage has hardly been depleted. The major concern is the effect of withdrawal on artesian pressures. Due to the size of the Basin, the relatively flat gradients and low permeability, the movement of water through the aquifers is extremely slow and independent of recharge. Hence, the normal concepts of sustainable yield (ie discharge should equal recharge) cannot be applied to the Basin as a whole as travel times do not allow for the effect of recharge to be seen away from the outcrop areas within management timeframes. The large volume in storage, though, can provide an extensive buffer to the impacts of temporary water needs. This effect should be considered when assessing the acceptability of fixed life projects such as mines and the extracted volumes from their operations. Identifying a sustainable yield involves balancing the acceptability of the economic, environmental and social costs with the associated discharge and fall in head, to arrive at an acceptable balance.

Jan 1, 2003

Pillar mining methods at the Pasminco Mining Broken Hill Operations are not new. Since mining commenced on Pasminco's leases at the turn of the century virtually every pillar extraction method tried throughout the world has been used. Much of the remaining mineral resource in the Pasminco Broken Hill leases is contained in pillars.However, due to the on-going need for mechanisation with bulk mining methods, and the very peculiar physical circumstances surrounding the formation of these pillars, their exploitation requires the development of a virtually new method based on excavation technology not previously used in the Australian mining industry. Trials of the method are to take place at the southern operations during 1991.

Jan 1, 1992

By M A. Gontalves, A F. D C Varajpo, S A. Stachissini

Clays from the Santa Elena Peninsula, south-east of the Ecuador coast, were investigated with a view to identifying their main mineralogical, physical, chemical and textural characteristics as well as their potential for industrial use as adsorbents. Identified as calcic bentonites, two representative samples from the Tosagua Formation (Oligocene to Lower Miocene) were selected for acid activation trials. The selection criterion was based on the greatest amount of clay fraction (<2 ¦m fraction) associated with the greatest content of montmorillonite. For the activation treatments, HCl and H2SO4 solutions of 4, 6 and 8 N were used in a stirred glass reaction vessel with the clay sample under reflux during four hours at temperatures of 70¦C for HCl and 85¦C for H2SO4. Mineralogical analysis by X-ray diffraction (XRD), chemical analysis by X-ray fluorescence (XRF), differential and gravimetric thermal analysis and measures of density, surface area and porosity indicated the changes occurred in the crystal structure of the montmorillonite. The acid treated clays were utilised in trials of purification and decolourisation of soybean vegetable oil in a ratio of 2:100 (clay/oil) at 90¦C for 30 min, under constant stirring. After centrifugation of the suspension, the wavelength of the bleached oil was measured by UV-visible spectrophotometer and the bleaching capacity of the clays was determined. The best bleaching capacity of the samples was obtained with 6 N H2SO4 acid-activated clays. The bleaching capacity was compared to Tonsil, a commercial acid-activated clay and similar results between them evidenced the potential industrial application of the Ecuadorian clays to bleaching of vegetable oil.

Jan 1, 2008

Jarrah Decline is currently the only underground operation at the Boddington Gold Mine, (BGM). The mine is located 120 km SE from Perth in WA, with mineralisation hosted within deeply weathered felsic and intermediate intrusions and volcanic rocks of the Saddleback Greenstone Belt (Morley and McBride,1995). Open cut operations commenced in April 1987 with a mill throughout of 3.OMtpa. A number of upgrades have since taken place, with the oxide material throughput currently milled at a rate of 7Mtpa. In 1992 a separate circuit, the supergene mill, was commissioned to treat copper material from the open cut and now ore from the Jarrah Decline. Current throughput in the supergene plant is 30,000 tonne per month, with a varied blend according to mill requirements. Total gold production from the Jarrah Decline in 1994 was 60,000 ounces from 90,000 tonne of ore.

Jan 1, 1990

By Jensen B, Ofori P, He Y, White E, Stanmore B, Brien M, O&apos

As part of a large AMIRA project, an on-line moisture meter was installed at two mine sites in Central Queensland. This project investigated the factors which control the moisture content of coarse (>0.5 mm) coal from the centrifuges used in conventional coal preparation plants. It was placed immediately after the first centrifuge to isolate the factors pertaining to one machine and its feed.The meter was found to be accurate and precise when compared with manual and mechanical sampling methods. The Grubbs estimator technique indicated that its precision is better than 0.3 per cent at the 95 per cent confidence limit.It has been identified that:1. the variability of the measured moisture contents of coarse coal can be described by normal distributions. Standard deviations of about 0.6 per cent are common; and2. the treatment of the coarse coal on the drain and rinse screens immediately prior to the centrifuge can affect the final moisture content.

Jan 1, 1995

It is generally known that Charters Towers was discovered by Mosman, Clarke and Fraser in 1871. However, the time was ripe, and these three were barely in front of others. There is one account that prospectors from Ravenswood visited the area months before but decided it was too far from water, and that one of them had told Mosman and party of the find. There is another account that Joe Larkins found the discoverers before they had registered any ground - this may explain Mosman's quick departure for Ravenswood.When the news spread, the rush was rapid, and there was soon a sizeable population: probably too many, as within twelve months the infant settlement was under considerable stress. First, the presiding Gold Commissioners had adopted "unusual and arbitary" interpretations of the Regulations, and many of the miners were aggrieved; Charters, the senior Commissioner, was accused of favouring moneyed interests, and of retiring ill whenever a brawl or confrontation occured. As a result, the law of the field soon became "the survival of the strong". Second, the settlers were, divided on where the main town should be: Millchester, near the water, or Charters Towers near the mines. Third, the discovery of gold at the Millchester Deep Lead in August, 1872 was followed by highly exaggerated accoants in_' the southern papers, apparently fabricated by local business speculators. The resulting rush resulted in hundreds of unlucky prospectors having to return or seek other fields. In that period two men were killed in squabbles over ground. To make matters worse, by October 1872 a drought had set in, water cost three pence a bucket, fodder was scarce, cartage expensive, and the price of crushing ore rose to thirty shillings per ton.

Jan 1, 1986

The mining industry provides employment opportunities for individuals from a wide variety of disciplines. Solid Energy New Zealand Limited (Solid Energy) is New ZealandÆs largest coal mining company and the career opportunities for school leaver trainees and university graduates are numerous. Solid Energy also provides fixed term opportunities for consultants and contracting companies, who complement the wealth of knowledge already within the company.   Focussing on Stockton Mine and my involvement there as an Engineering Geologist, this paper looks at Stockton Mine and the Stockton Water Management Project and outlines the career paths of other young professionals also working at Stockton.

Jan 1, 2007

In recent years new instrumentation and digital technology have Wrote possible a new facet of goo-physics: broadband seismology. From digitally record-ing networks and arrays. broadband scistnograrns of body waves that are flat to displacement and veloc-ity in at least the frequency range from 0.01 to 5.0 liz can now be routinely obtained for most carthquakes of magnitude greater than about 5.5. In contrast to data from conventional narrowband seismographs, broad-band body waves have sufficient spectral information to nvest,igate the many frequency-dependent eflects that may arise from source finiteness and from wave prop-agat ion phenomenon. Besides the usual parameters of depth. moment and focal mechanism, broadband data have sufficient spectral information to provide estimates of radiated energy, associated stresses and the frequency dependence of source parameters. Moreover. teleseis-mically recorded broadband data and near-field strong motion accelerograms overlap in the frequency band be-tween about 0.1-2.0 Hz. Thus. v it h broadband data it is possible to connect far field and near field data in order to make estimates of acceleration for almost any seismically active region of the circum-Pacific.

Jan 1, 1990

By Petersen V, Potke W, Polthier K

The paper reviews some of the aerodynamic factors in the blast furnace process and outlines the areas requiring further study. Detailed discussion is given to the pressure drop in both the dry and the wet zone of the furnace and an optimum coke size is suggested for minimum pressure drop. The effect of various charging sequences on the distribution of the gas in the furnace shaft is treated and notes on stack injection included. Flow phenomena limiting blast furnace output and the influence of aerodynamics on the movement of the bed in the furnace are outlined and these include fluidisation, flooding and raceway formation. A mention is made of alkalis, sulphur, zinc, softening, and oil injection and the mixed effect in blast furnace economics of increased tuyere velocity as problems requiring further research.

Jan 1, 1975

By C Glassock, P Tilyard, T Sandeman

Computer simulation is a well accepted tool for modelling the behaviour of large and complex operating systems. It is a particularly useful technique in complex operations where there are multiple interactions between the inputs and outputs of various unit operations. It can be utilised during the early stages of a project as part of the business case definition phase or the early engineering phases, or alternatively to help understand the various options available in an upgrade or expansion. With the design of a new processing plant to handle a different ore type at Lihir Gold Limited (Lihir), there was concern that the existing conveying system could separately handle the increased tonnages. A simulation model was constructed which allowed Lihir to examine the impact on the conveying system of the new process plant, as well as investigate the effect of different trucking options. As is often the case, once the simulation model was built, further understanding of the downstream bottlenecks was able to be investigated, including the sizing of critical equipment.

Jan 1, 2006

Goodenough and Fergusson Islands, in eastern PapuaNew Guinea, lie in an area of crustal extension on the western end of the Woodlark Basin seafloor spreading system. The islands are made up of a number of mountainous domes of complexely deformed basement, and these are intruded by large bodies of granodiorite. The domes are bounded by curved shear zones and faults dipping outwards at angles of around 25 to 45¦. The cores of the domes contain lower crustal rocks of eclogite and granulite facies, these rocks have undergone retrograde metamorphism in the outer sheared zones. Movement indicators on the shear zones indicate a complex moverm.-It geometry which does not fit the models proposed by earlier workers. These dome-like structures are similar to the metamorphic core complexes of the western United States Cordilleran region, however there are a number of aspects which do not fit with the models proposed for the development of metamorphic core complexes. Uplift of the metamorphic basement probably resulted from a combination of forces associated with the extension of the crust and the intrusion and emplacement of granodiorite plutons.

Jan 1, 1990

By M Wen, J Gerit, C A. Pelletier, D Muggli

On-land waste rock dumps at BHP Billiton Base MetalsÆ Island Copper Mine (ICM) near the northern end of Vancouver Island, B.C. continue to discharge ARD. These waters, which amount to approximately five million cubic metres each year, are injected into a three-layer, meromictic pit lake for treatment. The top layer is brackish water, replenished by each yearÆs rainfall (amounting to nearly 2 m/year). This top layer of water must meet effluent permit limits for heavy metals. This water eventually exfiltrates through a æbeachÆ waste rock dump, which is 93 per cent submerged along the north shore of Rupert Inlet. The middle and bottom layers of the Pit Lake are saline and currently oxic (2 mg/L dissolved oxygen) and anoxic (0.03 mg/L dissolved oxygen), respectively. Spreading of a liquid fertilizer every ten days throughout the top layer results in plankton and bacterial blooms that scavenge zinc, copper and cadmium out of this layer eventually to become mineral sediment in the bottom of the pit lake. Adsorption on planktonic skeletons and mineral precipitates also scavenges these dissolved metals from the middle and bottom layers to form bottom sediment. Sulfate reduction has recently begun in the bottom sediments. Diagenetic processes in the bottom sediments will eventually transform most of the dissolved heavy metals into insoluble sulfides. Cycling of ferric iron between the sediment and the water column and back seems to contribute dramatically to the biogeochemical metal removal processes. This biogeochemical system serves to maintain the top-layer water well within permit limits for discharge to the environment.

Jan 1, 2003

By Neill A. O, Worth I, O&apos

The formation of Kalgoorlie Consolidated Gold \lincs 1't% Ltd hati pla,xd all the major the gold producing areas adjacent to the city of Kalgoorlie/Boulder under one management, enabling the development of the 'Super Pit'. This has facilitated the economic optimisation of the resource. Optimisation has been achieved by the timely collection and presentation of data and the use of these data to reduce costs and improve planning procedures.In particular the following issues have been addressed:ò the reduction of the impact of the mining activity on the adjacent urban population centre,ò implementation of safety procedures for mining through underground voids,ò the determination of the optimum bench height and mining method for ore production benches and blast design. This system is fundamentally based on maintaining a high degree of selectivity while achieving a balance of relatively low unit operating costs,ò assessment of the comparable benefits of contractor versus owner operated earth moving equipment, andò the development of effective ore body models, production reconciliation and the long term mine planning procedures to facilitate effective strategic planning.

Jan 1, 1993