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By Millett R

In January 1989, Western Mining Corporation (WMC) acquired the Perseverance and Rocky's Reward orebodies and associated infrastructure from the Agnew Mining Company (AMC). AMC had closed the operation in August 1986 and it had been on care and maintenance since that time. To return the operation to full production as quickly as possible it was planned to mine the Rocky's Reward orebody by opencut mining and treat this ore whilst the underground Perseverance workings were rehabilitated. Removal of overburden from Rocky's Reward thus commenced immediately with a target of April 1989 for delivery of the first ore to the concentrator. Extensive rehabilitation and upgrading of the concentrator commenced in late January, and continued in stages for an 18 month period. The first stage consisted of overhauling all existing equipment and completing a crusher upgrade commenced by AMC prior to the mine closure. During this period, it was necessary to recruit a workforce and re-establish all the required support structure. In late April the plant commenced commissioning trials on mullock. The first ore was crushed on the 11th May 1989 and concentrate produced the following day. From May 1989 to June 1990 the plant was producing nickel concentrate whilst further upgrading continued. During this period, the flotation capacity was tripled by installation of a bank of eight Wemco 144L flotation cells in rougher-scavenger duties and two 12 metre by 2 metre diameter columns in cleaning duties. The existing vacuum drum filters were replaced by two Larox PF32 pressure filters, eliminating the need for solar drying and allowing the flash drier to be fed direct from the filters. These, along with a major borefield expansion and further work to the crusher increased the nominal plant capacity from 600,000 to 1,000,000 t/yr. The plant achieved the 1,000,000 t/yr rate in April 1990.

Jan 1, 1991

Unnamed early prospectors panned gold from creeks drain- ing the Great Dividing Range in the early part of 1851. The first publicised discovery was credited to Edward Hargraves near Bathurst in New South Wales later in 1851 and during the ensu- ing gold rush, prospectors rapidly made discoveries elsewhere in New South Wales and later across the border in Victoria. Reference to the attached graphs of gold production indicates that for much of the first 100 years, gold production came from the easily worked and readily discovered shallow alluvial deposits, many of which were located in the creeks draining mountainous regions of Victoria, New South Wales and Queensland (Fig. 1 and 2). As these deposits were exhausted, prospectors turned their attention to outcrop lode deposits which led to the development of underground mining techniques and a significant boost in over- all gold production. With the discovery of the rich Golden Mile lodes in Kalgoorlie in 1893, gold production increased signifi- cantly and peaked around the turn of the century. At that time, the enormous potential of the great Witwatersrand deposits in South Africa had only just been appreciated and for a few years, Australia led the world in gold production (1855-1863 and again in 1903). Underground mining continued in the Eastern Goldfields area of Western Australia, the Bendigo-Ballarat region of Victoria and in northeast Queensland. Very few of these operations continued beyond the Second World War, except the larger producers in the Kalgoorlie region where recovered grade had dropped to about 6 g/t Au. By the early 1970s with the gold price fixed at US$35 per ounce, most of the operations were shut down as labour costs escalated, with only the low cost bulk mining operation at Mt. Charlotte and the high grade reefs at Norseman continuing in Production.

Jan 1, 1988

By Haslam C. O, Taylor S

Four historical periods of Australian lead-zinc-silver exploration and development are identified.In the first period, 1841-1900, Australia's deeply weathered surface yielded bonanza deposits. The outcrops of easily worked secondary ores, enriched in silver and lead, were discovered by prospectors with the incentive of production at times of high silver price. Districts discovered in this period still contributed, in 1982, 60 per cent of Australia's lead-zinc production, mainly from Broken Hill.The second period 1901-1944, was one of strong mine development but stagnant lead-zinc-silver exploration. Mount Isa was discovered and developed, but otherwise effort was devoted mainly to the mining of deposit extensions and to the metallurgical flotation of zinc. The deposit discovery rate was low but the discovery of Mount Isa was so significant that discoveries of this period contributed, in 1982, 30 per cent of Australia's lead-zinc production.The third period 1945-1972 was one of re-invigorated exploration.New geological and geophysical surveys, developing concepts of ore genesis, and worldwide comparisons of orebody settings improved target area selection. Evolving remote sensing methods, and rapid analytical techniques, assisted detection of lead-zinc deposits. Initiation of exploration led to discovery:1. in regions of previously unsuspected lead-zinc-silver potential (Sorby Hills, Mons Cupri, Golden Grove).2. of poorly exposed deposits in recognized mineral districts (Hilton, H.Y.C., Woodlawn, Elura, Que River).3. during active exploration for another commodity (Brown's, Woodcutters, Mary River, Beltana, Lady Loretla and Pegmont).The period saw a sustained growth in lead-zinc-silver production mainly from established operations. Mines discovered during the third period contributed, in 1982, 7 per cent of Australia's lead-zinc production.In the fourth period from 1973 to the present, exploration initiatives became fewer but resulted in continued discovery of poorly exposed deposits at Teutonic Bore, Thalanga, Benambra, Scuddles, Hellyer, and Jillawarra. Development initiatives strengthened in the period and production commenced at Woodlawn, Teutonic Bore, Que River and Elura; pre-feasibility work commenced at Scuddles, Hilton, Lady Loretta and Thalanga.

Jan 1, 1984

By E R. Ramanaidou

The presence of clays in channel iron deposits (CID) within the Pilbara region of Western Australia causes problems in the classification and subsequent processing of the iron ore. In particular, the presence of clay adversely affects the processing and ore metallurgical properties by increasing the amount of Si and Al. Iron ore companies are seeking new methods to quickly and objectively detect the type and amount of clay in these deposits. Traditional methods of clay quantification such as X-ray diffraction (XRD) and thermal analysis are time consuming and expensive. Reliance on bulk chemical techniques (eg X-ray fluorescence, (XRF)) to derive normative mineral abundances can give misleading results. For example, the replacement of Fe by Al in the structure of the iron oxide minerals, goethite and haematite, which dominate in CIDs, can be significant. Silicon can also occur in association with these Fe minerals. If not accounted for, chemical techniques may overestimate the normative abundance of clays. In comparison, reflectance spectroscopy in the visible-to-near infrared (VNIR) and short wave infrared (SWIR) wavelength range (eg 400 - 2500 nm) and Fourier transform infrared (FTIR) (6000 - 900 cm-1) analysis are non-destructive techniques that can provide rapid and objective mineralogical information. Both techniques are particularly suited to Al-, Fe- and Mg-OH bearing minerals such as clays. Kaolinite and, to a lesser extent, montmorillonite are the most common clay contaminants that occur in the Pilbara CIDs. Previous applications of VNIR-SWIR spectroscopy have demonstrated the potential of these methods in quantifying the clay mineralogy of CID ore. In this study, variations in the depth of diagnostic spectral adsorption features in the SWIR wavelength range of kaolinite and montmorillonite in standardised mixtures, with known proportions of clay, were well correlated to the abundance of kaolinite and montmorillonite, and to the clay alumina content (ie per cent Al2O3 û clay).

Jan 1, 2007

Forty two new apatite and zircon fission track analyses on the Kubor-Marum-Bena Bena area of northern Papua New Guinea severely constrain the timing of tectonic events and hence the tectonic models for New Guinea, particularly arc-continent collision. In addition, the data can be analysed regionally in terms of known and assumed lithospheric fault zones inferred to control mineralisation (eg. Corbett 1994; Kendrick et al 1995; Hill et al 1996) to determine reactivation of these zones. When combined with the new kinematic plate models for the evolution of New Guinea (Hall 1997) there is the potential to predict likely zones of mineralisation. The low-medium grade? Palaeozoic rocks of the Bena Bena terrane yielded a zircon fission track age of 17 Ma, indicating the time of cooling below 200¦C. The age is consistent with `the shift, at about 16-18 Ma, from volcanolithic sediments to mixed provenance sediments rich in quartz and metasedimentary lithic fragments in the southern Finisterre Ranges (Abbott et al. 1994). This shift was recorded in the Sukurum Formation, which ranges in age from Middle Miocene to Pliocene with quartzose and metasedimentary grains in all samples. Although recording rocks at temperatures of 200¦C and hence depths of ---5km, the 17 Ma age suggests the Bena Dena terrane was rapidly cooling at that time due to uplift and erosion, supplying metasediments to the southern flank of the Finisterre Range, currently 100 km to the east. Significantly, the Middle Miocene Akuna Intrusive Complex, dated 14-17 Ma by Page (1976), lies almost entirely within or adjacent to the Bena Bena terrane. Potentially the uplift, erosion and cooling of the terrane at 17 Ma may have been caused by the rising plutons. If so the 800 sq km exposure Akuna Intrusive Complex at the SE end of the Bena Bena terrane may have been the focus of uplift and supplied the metasedimentary detritus to the Finisterre Range. This suggests that the Finisterre Range was not far removed from the Bena Bena terrane, perhaps less than the 200 - 400 km indicated by Abbott et al (1984). The Akuna Intrusive Complex probably resulted from subduction of the Solomon Sea Plate beneath the PNG margin. In order for the subducted slab to reach depths of -100km below the area to facilitate partial melting and plutonism (Hamilton 1994), subduction probably commenced 3-5 Ma Ma before plutonism, ie at or prior to 20 Ma suggesting a significant change in the tectonic regime at -20 Ma, perhaps related to collision of the Solomons - Ontong Java Plateau collision (eg. Hall 1997). The main result to emerge from the 28 apatite fission track analyses is that the whole of the study area underwent rapid cooling due to uplift and denudation in the Late Miocene, mainly between 7-10 Ma. Results from several samples indicate that they were not totally overprinted prior to uplift indicating maximum burial of -3 km in the Middle Miocene, assuming normal temperature gradients. The burial is less if higher gradients are assumed, allowing for Middle Miocene plutonism. The Late Miocene cooling in the Mobile Belt agrees well with the Pliocene to Recent cooling in the Fold Belt to the SW, interpreted to be due to uplift and erosion associated with fold and thrust deformation of the Miocene Limestones (Hill & Gleadow 1989). This timing relationship suggests, that compressional deformation in the Mobile Belt occurred in the Late Miocene, at 105 Ma, and that the deformation migrated towards the undeformed foreland in the southwest in the Pliocene, at 5-2 Ma. The regional Late Miocene uplift and denudation in the Mobile Belt is also consistent with that postulated by Crowhurst et al (1996; 1997) for northwest PNG, although they considered the event to have occurred mainly from 8-5 Ma. If so, then the uplift and denudation may have been migrating from east to west as well as to the south into the Fold Belt. These timing relationships place significant constraints on tectonic models for the area, indicating that the major compressional pulse in PNG commenced in the northeast at -10 Ma and migrated to the southwest and west in the latest Miocene to Pliocene. This suggests that the initial arc-continent collision and associated shortening occurred in the Late Miocene around -10-12 Ma. This immediately followed intrusion and cooling of the Akuna Intrusive Complex at -17-14 Ma and the Bismarck Intrusive Complex at -12.5 Ma (Page 1976), indicating a linkage between the end of plutonism and the start of compressional deformation. The timing is consistent with the observation of Hamilton (1994) that in areas of subduction `the common regime in overriding plates is extensional and leading edges are crumpled only in collisions. This suggests that the Middle Miocene magmatism in northern New Guinea occurred during extension above a subducting slab and was terminated by Late Miocene arc collision and resultant compression commencing at -10-12 Ma. In general, these data indicate that the acme of denudation and cooling in the Mobile Belt was in the Late Miocene, with relatively little denudation there since. In contrast, Hill & Gleadow (1989) found that the peak of denudation in basement outcrops in the Fold Belt was in the Pliocene at -4 Ma. However, in this study some samples from the Mobile Belt yielded Pliocene ages or high

Jan 1, 1997

By R Polmear, G Mauger

You wouldnÆt start excavating before testing core samples, so why would you approve a project plan before all factors have been identified, reviewed and addressed? Even a champion sports team made up of the best players canÆt produce optimal results without a well understood and agreed game plan. Could an F1 racing team produce their outstanding performance without rigorous evaluation and testing of the factors for successful performance? Why would we expect a capital works project team to be able to get it right without an understanding and an involvement in setting and implementing the overall game plan and without an understanding of all stakeholder requirements? For International PowerÆs Hazelwood (IPRH) mine in Victoria, the challenge was development and delivery of a 40 year mine plan, ultimately involving relocation of existing mine operations into an adjacent new coal field, land acquisitions and major environmental and other approvals to allow diversion of three streams, a highway, an Over Dimension route and other infrastructure in a political and environmentally sensitive atmosphere. The lessons from International Power HazelwoodÆs (IPRH) experience are: that the clear set of project principles and guiding values ensured delivery of a robust plan; a robust plan can withstand significant change; and value management (VM) played an important role in providing assurance, to all, that the plan was sound at both the strategic and micro levels. This Hazelwood mine project included five major VM workshops. The first was a critical review process in addition to design and cost reviews. This VM workshop was used to analyse, at a high level, the preferred coal mining sequence and design concepts, together with the interaction between design elements, risks and costs. In addition to this, the workshop provided an agreed common pathway for all downstream decisions. A second VM study was conducted to ensure that the proposed plan and design for relocation of the conveying systems from the existing mine into the new field were planned for optimum achievement from a whole of life cost, time, operational and maintenance perspective, plus the logistics of continuing operations while relocating assets. A third study followed to review the Conveyor Transfer Alliance and review functional design. A fourth VM study workshop was formed at the start of Phase 2 Alliance to ensure that the best value for money was being achieved through the current design, schedule and project arrangements and that all interfaces between parties had been reviewed and responsibilities were clear and understood. Other studies are outlined later in this paper. This paper details the evaluation criteria and processes used in the project evaluation that led to the WestField Mine Development.

Jan 1, 2007

HISTORY OF PROCESS DEVELOPMENT The manufacture of coke from coal commenced at the beginning of the 17th century by heaping coal into circular mounds in the open, covering with earth, clay or ash and slowly burning the coal in the mounds to produce a heap of coke. Naturally the process was slow in production rate with low coke recovery due to the loss of that part of the coal which was completely burnt to ash. As a natural consequence of this initial carbonisation method, a coke oven design was developed so that the coking chamber, which was constructed of brick, was circular in plan, cylindrical in section with a dome shaped roof - similar in shape to the original coal mounds. As the shape of the chamber was similar to the old dome shaped beehive, the ovens were called beehive ovens. The ovens were built in long single or double rows with retaining walls between each oven and as such were known as a battery of beehive coke ovens. In these early beehive ovens, coal was charged from hand wheeled tubs into a hole into the top of each oven, hand- levelled with a rake and the oven side opening sealed with bricks and clay except for some small holes in the opening to admit limited quantity of air for combustion. Coking commenced by the heat retained in the brickwork from the previous charge. The gases evolved from the coal, together with the admitted air, were partially burnt inside the oven to supply the heat for carbonisation and the surplus gases were burnt to waste at the top charging hole. The heat from this gaseous combustion inside the oven together with the reflected heat from the brickwork of the arched roof of the oven allowed carbonisation of the coal charge to proceed from its surface slowly downwards to the floor of the oven. At the end of the coking cycle (usually 4 or 5 days) when there was no more evolution of gases, as indicated by diminishing gas flame and a drop in oven temperature, the brickwork of the oven opening was removed. The coke was then quenched by inserting a pipe with spray holes to spray water over the coke charge in the oven after which the coke was raked from the oven. The work of charging and levelling the coal, bricking and removal of oven opening, quenching and raking out the coke all required manual labour. As these ovens only carbonised a 5 to 7 ton charge of coal per cycle of 4 to 5 days, to produce 3 to 41/2 ton of marketable coke, the labour required per ton of coke was high.

Jan 1, 1975

In the course of an investigation of the influence of bismuth on copper carried out some years ago, (1) the author found that phosphorus exerted a beneficial effect on bismuth-copper alloys of low bismuth and oxygen content by neutralizing the embrittling effect of the bismuth. In the intervening years, a further examination of bismuth-phosphorus-copper alloys has been canied out and the influence of other elements and combinations of elements on copper containing bismuth has been studied.The results recorded in the present paper are part of this investigation.MATERIALSAll the alloys were made from high-grade copper (KS.A. wire-bar) of the following composition: copper 99·95%, oxygen 0,040'%, iron 0·0015%, sulphur less than 0-001%, bismuth less than (j>'OOl%, other elements each less than O· 0010/<-. The bar was hot rolled and cold drawn to strip which was cut into short lengths and cleaned in nitric acid ready for melting.A piece of this 'strip was drawn to wire 0·08 in. diam., annealed at 5000 C, and measured for electrical conductivity as a check on purity. The result was 101·5% of the I.E'.C. standard.In making the alloys, phosphorus was added as 14% phosphor-copper, bismuth as 17% bismuth-copper, and the other constituents either as copper alloys or as elements of a high degree of purity.PREPARATIQN OF STRIPSThe charges were melted in plumbago crucibles (Morgan salamander brand) in an oil-fired furnace, Le;, in the manner commonly adopted in industrial practice. The copper was first melted under charcoal, well stirred with a chaned stick, and the necessary alloying elements added and stirred in with the stick. The weight of a charge varied according to requirements but generally was about 4 lb. The charges were poured into slightly tapered brass moulds heated to about 1000 C and dressed with a mixture of mineral oil and tallow. They were not only poured under charcoal through the burning mould dressing but also- through a ring of flame produced by burning kerosene on asbestos cord wrapped round the top of the mould. Experiments carried out with plain copper proved that by this means oxygen could be excluded from the stream of metal. The billets were 7·5 in. long x O·83 in. diam. x 1·3 lb. weight.The billets were cropped about 1 in. from the top, cleaned in nitric acid, and measured for density by the usual method of weighing in air and -in water. As these measurements were required only as a check on casting, technique a high degree of accuracy was not essential (accuracy = -+ 0·2%).

Jan 1, 1942

Life inside the mining family was regulated by the mine. The whistle shrieked the change of shift to the Cornish, Welsh and German miners digging the alien soil for copper at Burra in the 1840s and the deep quartz gold mines at Bendigo in the 1880s.During the golden years of alluvial mining in the 1850s, and later out on the frontier fields of Kalgoorlie and Jarrahdale in Western Australia, the lure of the mine dominated family life. How could it do anything else? The canvas tent, bark hut or weatherboard cottage in which the mining family lived close by the mine facilitated prompt access. The working man of the family attended to the demands of the mine first, and those of his family afterward. Who then organized and nurtured the mining family? The role of the mining wife was multi-fold. She played the traditional roles of home-maker and comforter, raising her children, tending her house and vegetable garden and supporting those friends and acquaintances who had lost children to disease, or menfolk to the mine. Epidemics of measles, the whooping cough or influenza carried away children in infancy or at too young an age. The death of a husband through accident or disease (pthisis was a likely killer) forced upon the mining wife another role, that of provider. When Elizabeth Vigus' husband died in a Bendigo mine accident in March 1880 Elizabeth set up a grocery business to support her young children.' But in other cases the mining wife supplemented the family earnings by part time work, not in the mines for the Mines Act legislation of 1842 forbade the working of women underground, but in auxilfiary occupations which were in demand.2 Ann Mitchell, a herbalist ,found plenty of work in the goldfield towns of Daylesford and Maldon in the 1860s and 1870s.3 So too did Susan Rule and her daughter Catherine who conducted a sewing and millinery establishment in Beechworth in the 1870s.4 The making of the family's clothes was another task of the mining wife and mother.Until the wonderful invention of the sewing machine, this was a tedious and time-consuming task. James Slater Edmonson bought his wife a Wertheim for the sum of 12 pounds in June 1886, just before leaving her and his chil- dren in the Adelaide suburb of Goodwood whilst he went alone to the goldfields of the West. In October of that year he wrote to Louise telling her how he missed the childrens' wondering "whether Slater wore my old shirt now. I always think of him as he sat on my knee at breakfast in that old shirt; and how pleasant it would be if I could rock both of them and sing as I used to do".5

Jan 1, 1988

The mechanism of caving is of interest to the mining engineer only in areas where he is directly concerned. One area is surface subsidence which is outside the scope of this paper. Another area is at the face where coal is being extracted and where control of caving is of vital importance. Coal mining systems have been developed with many considerations in mind, but in this list of considerations, strata control has seldom been given much importance. Research is in progress in Australia to endeavour to determine an optimum sequence for coal extraction underground. As information becomes avail- able from this work it is hoped that appropriate methods of controlling caving in various strata conditions will be devised. When this is done, equipment may be introduced to permit the mining operation to proceed under optimum conditions for strata control, rather than devising a mining procedure to suit the equipment available and methods developed for other reasons.

Jan 1, 1974

By J E. Everett

When ore is being selected from a regularised block model, a common procedure is to accept as ore any block whose iron content exceeds a cut-off value, and whose content in each contaminant analyte is below an appropriate cut-off value. This method defines a quadrant within the multidimensional analyte space, such that any block lying within the quadrant is accepted as ore and any block lying outside the quadrant is rejected as waste. The cut-off levels can be adjusted to maximise ore tonnage at a target grade (or analyte vector). When the method is applied to a project comprising multiple pits with systematically differing grades, it is found that ore tonnage at target grade is maximised if different cut-off quadrants are used for the different pits. This is apparently illogical, because it implies that an ore block from one pit may be accepted as ore, but an identical block from another pit is rejected as waste, even when ore from both pits is to be blended into the same product and there are no production cost differences between the pits. The paradox is an example of the ætheory of the second bestÆ: if there are multiple conditions for optimality and one condition is broken, then obeying the other conditions may not be the best policy. The problem lies with the quadrant cut-off method, which is shown to be inconsistent even for selecting ore from a single pit. A criterion that is inconsistent cannot be optimal. It is shown that a linear composite cut-off function provides maximum ore tonnage, and that a single composite cut-off criterion is consistent and optimal over multiple pits. Further, it is shown that a composite cut-off function not only maximises ore tonnage at a specified composition, but also can be used to select ore so as to maximise project value, if marginal costs and values are available.CITATION:Everett, J E, 2013. Selection of ore from multiple pits, in Proceedings Iron Ore 2013 , pp 185-192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Yushan Ma, Jiqing Wang, Hanyi Jia

The Hedong Gold Mine is located in the Yantai area, Shandong province, China. It is an underground mine with an annual gold output of some 700 000 grams. The orebody is located on the edge of the Wanger Shan metamorphism zone, and the hangingwall of orebodies is thus defined by a prominent set of fractures. The proximity of the metamorphism zone and the inclusion of the fracture set ensure that both the orebody and the country rocks are unstable. The main orebodies dip at an angle of between 40 to 45¦, with a strike length of 160 metres and a horizontal width of 50 metres. Surface subsidence in the area is not permitted. Cut and fill mining is usually practiced. As the mining operation proceeds to greater depths, the ore grade is diminishing and it is necessary to find a more efficient stoping method. Sublevel open stoping with sequential extraction and filling of each sublevel has been designed and applied in situ. This new mining method is called æsublevel open and fill stoping methodÆ in the mine. Experience to-date is that new mining method is satisfactory.

Jan 1, 1998

IN any assay office it is of paramount importance to keep the men interested in their work; and in order to do this, men on routine work, such as lead, zinc, and sulphur deterrrrinations, slag analysis, etc, should be changed around monthly. This gives some variety and helps to keep a man's interest on his work, so that better work results. It may be maintained that to keep a man on the same class of work indefinitely makes him more expert at his work. This is certainly true; but in assaying, where accuracy is so essential, it is absolutely necessary for a man to keep his mind on the work, and not 'get' into a mechanical method of working. He is also on the alert to discover means for shortening his analytical methods, and his capacity forwork is increased. Another advantage is that the men get a good all-round training, and one is never at a loss to replace a man on any class of work when he is absent from any cause. This tends to smoother and more efficient running of the assay department. In industrial assaying it is often advantageous to have a result quickly, so that it will be of maximum benefit in the running of some part of the plant, In such a case it pays to sacrifice a little accuracy to speed up a method. The shortest method is less costly, and a quick approximate method is all that is required to give the superintendent the requisite information. Time is thereby saved, and the cost is less. In carrying out assaying for any large industrial plant, such as a smelting works, there is always a tendency for superintendents running the different departments to send in more samples for assay than are absolutely necessary when no system of costing is in operation. Some of these samples may involve a lot of work and heavy expenditure, as, for example, the estimation of only one impurity in a sample of refined lead. If the superintendent knows that the cost of assaying all samples sent in by,him is charged up directly against...

Jan 1, 1922

By Folie M

Energy models are evaluated according to their contribution to policy decisions. The view taken is that if any model is to provide policy insights, it should be based on economic theory. The difference in modelling methodology between economists and technol- ogists is discussed. The technique of energy analysis is criticised. The basic structure of some of the large economic models is presented and their policy usefulness is Discussed.

Jan 1, 1977

The perception of New Zealand as an exploration destination has improved compared with other countries. There has been a realisation that New Zealand's potential is greater than previously thought. Other countries are not as attractive as before, and explorers are looking at alternatives that are geologically prospective and politically stable.   New Zealand is regarded as geologically prospective, especially for gold, with potential for world class deposits. It is also prospective for other metals, coal and industrial minerals. New Zealand is politically stable, and has an economy that is attractive to overseas investors. It is one of the least corrupt countries in the world, which overseas companies see as providing a high degree of certainty for investment.   New Zealand has good opportunities for investment in gold exploration at present. Otago has been the focus for new companies and is the favoured exploration location. Otago is regarded as very prospective, and hosts New Zealand's largest gold deposit at Macraes. There is potential for other similar deposits elsewhere in Otago.   The mineral industry previously had an excessively pessimistic view of New Zealand, which has resulted in little new investment in New Zealand for some years. Previous pessimism is turning to optimism, and there is increasing interest in New Zealand as an exploration destination by overseas explorers.

Jan 1, 1997

The theme of the conference this year is diversification. One way to diversify is through acquisition. The principle underlying the winner's curse is that in competitive bidding situations where the value of the asset bid for is uncertain the winning bid will overstate the true value of the asset. The successful bidder is blessed with the winner's curse. What this paper will explore is to what extent this is true; how acquirers can avoid being blessed with the winners curse; and show how joint venture deal structures are used within the mining industry to avoid the winners curse.

Jan 1, 1996

By Ketteridge IB, Mulcahy DE, Quast KB

The long term energy demands in South Australia are such that there is a distinct possibility that one of the lignite deposits in the State will be exploited to feed a pulver- ised-fuel power station. Bowmans lignite deposit is the largest lignite deposit in South Australia and is considered to be a contender. The deposit is ideally situated (100 km north of Adelaide) but the quality of the lignite is poor (see Table 1). TABLE 1

Jan 1, 1984

The metallurgical works of the Electrolytic Zinc Company is situated on the Derwent Estuary, approximately five miles north of the city of Hobart and near a relatively dense housing area. Zinc concentrates, consisting chiefly of zinc and sulphur, have been roasted at Risdon for 53 years;- recently at rates of 1, 100 tons per day. The zinc content of the ores is converted to zinc calcine (ZnO), which is a dusty material. The calcine is leached with acid to form zinc sulphate, which is then electrolysed to make zinc. The sulphur is oxidised during roasting to sulphur dioxide, part of which is converted to sulphuric acid and part is dissolved in estuarine water which is then discharged to the Derwent Estuary. Photographic slides were exhibited showing the unaffected green flora of the nearby hills, of clear exit stacks, of green lawns, and of a w ll lrcnt nines hnlP anlf nniir.qa within the Wnrka hnnnrla_rv_

Jan 1, 1971

A useful sampling device can be constructed using three movable flaps. One is moved between its two extreme positions as material is flowing past it; the other two are only moved while no material is flowing past them. Material commences to flow into a sample container as the primary flap is moved from right to left, continues to flow into the sample container as the primary flap is moved from left to right, and the flow is terminated as the primary flap is next moved from right to left. As for several other sampling devices, an argument that there is no delimitation error can be made on the basis that the sampler conceptually divides the stream up into discrete portions and takes a set of equally-spaced portions as a sample.

Jan 1, 2008

THIS instrument, depends on the principle that, over a short period, the surfaee of a porous substance from which a liquid is evaporating receives the same amount of heat by conduction, convection, and radiation as it loses in the latent heat of the evaporating liquid. If, then, the amount of heat being received by a surface can be measured, the rate of evaporation can also be obtained. The Kata thermometer is also based on this principle differently applied.The instrument, as shown in Fig. 1, consists essentially of a thermometer with a sliding which is divided by three pointers into two equal parts which may be spaced so as to cover a distance of, for example, 5° of the thermometer scale. The instrument is calibrated so that the amount of heat required per unit area of the bulb to raise the menissus is known. The method of using the instrument is as follows:The slide is first set so that thc central pointer is at the temperature of the evaporating surface.The thermometer is cooled by any convenient means so that the meniscus is several below the lowest pointer. The thermometer is then placed near the evaporating surface, when the Ineniscus begins to rise and the time taken for it to rise from the lowest to the top pointer is measured. From this and the calibration results the amount of heat retained per unit area of the bulb at the mean temperature...

Jan 1, 1928