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By D Craw

Middle and Late Cenozoic fluvial conglomerates and gravel in northeastern Southland record the transport of alluvial gold from Central Otago into Southland, and subsequent reworking and concentration of this gold into economic placer deposits. A corridor of geochemically distinctive, Hg-free gold derived ultimately from veins in Torlesse Terrane schist in Otago extends through the Caples Terrane and into Southland. The initial repository in Southland was fluvial sediment of the East Southland Group, specifically weakly auriferous, quartzose delta plain strata of the Gore Lignite Measures (GLM), a downstream equivalent of Dunstan Formation in Central Otago. Miocene uplift along the northwest trending Old Man Range beheaded the parent river system, isolating GLM from its Central Otago source area and establishing the proto-Waikaia River system. Rising topography between Otago and Southland increased fluvial gradients, and initiated erosion of cover strata and a sequence of tectonically induced gold recycling events. Auriferous GLM were recycled from the hinterland into broad braided fluvial channel and floodplain deposits of the Waikaia Group (new), specifically the highly auriferous Waikaka Quartz Gravels and equivalent Waimumu Quartz Gravels downstream (WQG), superimposing more proximal depositional environments over parts of the former GLM delta plain. WQG were deformed, and locally cannibalised during the later stages of their deposition by reverse movement on north-northeast trending faults of the Dunsdale System (NW side up). Increased tempo of uplift in the hinterland (Old Man, Garvie, Umbrella, and Blue Mountain Ranges) in the Pliocene and early Quaternary resulted in further reworking of GLM and WkQG from the hinterland as well as basement erosion. Progressively more basement-rich detritus was deposited as a locally auriferous piedmont (Gore Piedmont Gravels - GPG) over earlier channel and delta plain (GLM, WQG) strata, extending from the Blue Mountains to Waikaia, and southward through the Gore Gap to beyond Mataura. Southward propagation of the north-northeast trending ranges, local warping, and uplift of the Murihiku Terrane in Pliocene and Quaternary progressively deflected GPG fluvial systems and ultimately constrained them to the present valleys. Pre-existing auriferous strata (GLM, WQG, GPG) were reworked and deposited with or without basement detritus as these fluvial systems migrated toward their present positions. Auriferous remnants of these transitional deposits are preserved in local structural depressions on the uplifted blocks that deflected the systems (eg King Solomon Mine), and on locally abandoned floodplain segments on the lowlands (Pebbly Hills-Gore Gap). The present drainage has continued to incise and cannibalise its own and earlier deposits during late Pleistocene-Recent uplift to form confined channel placers within the present valleys.

Jan 1, 2002

By Propster M, Choudhry M

THIS note gives comments on the paper by Kitaev et al on p. 68 of this book and compares results with those obtained by ourselves. We wish to say that the authors are to be congratulated on their sophisticated approach to an important problem and that it complements our efforts on flow maldistribution.1-5 It is our view that Eqs. (1)-(5) on p. 69 are impressive, but unfortunately with present day computers and computational facilities, it would be quite impractical to contemplate the numerical solution of these. Eq. (8) in the authors' paper, on p. 70, does provide the logical starting point for tackling flow maldistribution problems and strictly speaking this equation is more accurate than Eq. (1) in our paper in this book. We note in passing that there is direct experimental evidence to support the contention that our Eq. (1) is at least a reasonable approximation and one may question in a practical sense whether the refinement afforded by Eq. (8) in the paper by Kitaev et a/ is justified. While one must readily accept the appropriateness of Eq. (8) of Kitaev et al as a starting point, the subsequent mathematical manipulation by the authors is open to serious criticism. In order to solve this complex, non-linear equation Kitaev et al postulated irrotational flow, which afforded considerable simplification. One can argue simply on physical grounds that the assumption of irrotational flow is inappropriate, a fact which should be readily apparent on inspection of the flow fields shown in Figs. 2 and 3 of Kitaev's paper. It follows that while the starting point through the use of Eq. (8) is correct the results derived from this starting point may be suspect because of the erroneous nature of the irrotational flow assumption.

Jan 1, 1975

With mining development on hold and other underground works in a slowdown, the develop- ment of nuclear waste repositories takes center stage on the American rock engineering scene. Three repositories for commercial spent fuel -- in salt, tuff, and basalt -- are in the phase of site characterization and conceptual design, and one pilot project for defense high-level waste in salt is under construction. A repository design for crystal line rock has recently been postponed. Because of strict quality assurance requirements throughout design and construc- tion, and because of the need to predict and ascertain in advance the satisfactory perfor- mance of the underground openings, much intellectual energy has been expended to analyze underground openings in the unusual circumstances of the repository environment. In the long term, these efforts will lead to an improved understanding of rock behavior and improved methods of underground analysis and design. For the shorter term, a formalized ground control plan was developed, the princi- ples of which may be applied to other types of projects. This paper summarizes the status of underground design and construction for nuclear waste repositories and presents some details of the ground control plan and its individual elements.

Jan 1, 1987

By Toguri JM

A solid electrolyte technique has been used to measure the activity of cobalt in liquid cobalt-gold alloys containing between 0.085 and 0.50 mole fraction of cobalt, and for temperatures from just above the liquidus to around 1550 K. The system exhibits positive deviation from ideality, both in the activities of cobalt and gold, and in the enthalpy and excess entropy of mixing. The results agree with previous measurements using a Knudsen cell - mass spectrometer technique, but differ from those reported for a gas equilibration method. The data have been used to calculate the activity coefficient of cobalt oxide in silica saturated iron silicate slags and to express the solubility of cobalt in such slags as a function of cobalt activity and oxygen pressure.

Jan 1, 1984

This paper reviews the issues of mining machinery automation with special emphasis on underground applications. Automation is desirable because it offers the following advantages: ò increased safety by reducing human exposure to hazards of underground mining; ò higher productivity; and ò reduced wear of equipment. In spite of these advantages and in spite of numerous attempts over the past several decades, mining automation has been a difficult proposition, partly because no two mining operations are exactly alike and these operations are carried out in an unpredictable environment. This is the main difference between automation in factories and in mines and that is why mining automation has been lagging so far behind factory automation. Automation is possible only when the machine 'knows' its workspace. In a factory, this workspace can be 'described' to the machine because it is sufficiently controlled. In a mine, the environment undergoes continuous change and the only way the machine can 'know' its workspace is through real-time sensing.

Jan 1, 1995

By Cheung L. C C, Maconochie A. P

SIROFRAG is a computer-based imaging system that quantifies the post-blast rock fragment size distribution in a muckpile in a mine environment. Improvements in blast performance and blast modelling are being hampered by a lack of a quick and objective method to evaluate the major result of the blast: the fragment size distribution. This is usually done by hand digitising muckpile photographs: a labour intensive and tedious process. SIROFRAG is being developed to quickly, cheaply and objectively provide this information. SIROFRAG is based on active stereo image analysis. It uses a light stripe to illuminate a muckpile and a pair of video cameras to determine the 3D nature of the scanned objects. The imaging system is based on a novel prototype scanning projector that allows images to he captured in full daylight. The Microsoft Windows based software controls the projector and interprets the captured images to provide a size distribution of exposed rock fragments.

Jan 1, 1995

The 1980's have produced an outstanding revival of the Australian gold industry. In contrast to some previous mining booms, the economic aspects of the growth in gold production are soundly based. In general the new developments have been highly profitable and this is beneficial to all parties- whether they be government, shareholders employees or suppliers. Mining companies are showing a large commitment to gold exploration with approximately 50% of Australian exploration budgets now being directed towards gold. An increasing proportion of this expenditure is being channelled towards the eastern States with Queensland 'being the major centre of interest. Further strong growth in production is expected with some 50 projects likely to come on stream before 1990. A very significant aspect of the foundation for this growth is a continuation of the existing tax status of the industry.

Jan 1, 1987

The dielectric properties of practically all oxide and sulphide ore minerals are such that they heat rapidly when irradiated with microwaves particularly at the standard frequency of 2450 MHz. The presence of carbon or low rank coal mixed with the minerals still further enhances the heating rate. Amongst the patented technologies being investigated are: (i) the direct reduction of oxides with or without carbon included in the pellets or briquettes; (ii) microwave precursor heating of composites ahead of smelt reduction; (iii) microwave smelting of ore or concentrate mixtures with carbon, sometimes assisted with oxygen. Microwaves appear to stimulate endothermic reduction reactions as readily as they do exothermic oxidation reactions. Being a method of achieving "bulk" heating, composites or columns of ore-char blends rapidly heat throughout rather than from the outside inwards as in conventional heating. The microwaves of themselves do not generate any gas - the only gases to be cleaned are the products of reaction in the composites or blends, plus the products of oxygen smelting. In the case of sulphide composites, depending on the quantity and type of low rank coal or char present, sulphur may be eliminated, and collected, in the elemental form. Furthermore, reactions seem to take place at lower temperatures than in conventional smelting but no doubt at the "points" where actual reactions are taking place the atomic or molecular vibrations are such as to satisfy the laws of thermodynamics. Examples are given of the production of unusual products of smelting sulphide concentrates and also the alloys produced from refractory minerals such as chromite and ilmenite. The techniques have been used to produce products with as wide a range of melting points as relatively pure tin and tungsten-molybdenum alloys. Special equipment is being designed and evaluated for these new fields of pyrometallurgy.

Jan 1, 1989

In response to requests from the iron ore mining industry, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Division of Mineral Physics has developed a number of bulk analysis techniques in which analyses are obtained directly from ore samples weighing many kilograms or from ore located on conveyor belts.Because penetrating neutron and gamma radiation is used, measurements are obtained from a large volume of ore, which ensures thal the analyses are represelllative of the bulk.Two different gamma-ray techniques have been developed to measure iron ore grade. The first is based on backscallering of 60CO gamma rays, while the second involves measurement of the annihilation radiation which arises when the ore is irradiated wilh 226Ra gamma rays. Both techniques measure the iron concentration with an accuracy (1 s) of better than 0.4% Fe.A thermal-neutron irradiation technique using a 252Cf neutron source has been developed for the simultaneous determination of iron and the aluminium impurity (expressed as AI2O3) in iron ore fines on a conveyor bell. Because the conveyor speed must not exceed about 0.05 m/s, if good accuracy for AI2O3 is required, an auxiliary analysis bell is required Lo avoid inLerference with normal ore processing. Dynamic trials have demonstrated that accuracies of 0.6% Fe and 0.1% AI2O3 can be obtained.

Jan 1, 1985

The Olympic Dam copper-uranium-gold-silver deposit, located 520 km NNW of Adelaide, S.A. was discovered by Western Mining Corporation Ltd in 1975, and is now being developed as a joint venture between WMC (5107o) and the BP Group (4907o). The discovery of this deposit resulted from the application of a conceptual model for the formation of sediment-hosted copper deposits. This model postulated that the oxidation of basaltic rocks could release significant amounts of copper into solution and that, under favourable conditions, these solutions might pass upwards along faults, and the copper be precipitated in reduced- facies sediments higher in the sequence. The Stuart Shelf province was chosen for exploration because geological interpretation suggested the presence of suitable basal- tic source rocks at depth, and favourable host sedimentary rocks in the overlying sequence. The Olympic Dam site was selected for drill-testing because of the presence of coincident gravity and aeromagnetic anomalies suggesting the presence of basalts and/or mineralisation at depth. This site also had a favourable tectonic signature, indicating the presence of deep crustal structures which might have allowed fluid migration.

Jan 1, 1988

By Smith F. A, Both R. A

The application of biogeochemical methods in mineral exploration in the semi-arid to and environment of Western Australia was investiga- ted in an area near Norseman. The reliability of these methods was evaluated by comparing trace element characteristics of rock, soil and plants in the vicinity of the Pioneer BB pros- pect. The prospect is located in the south- western part of the Pioneer Dome, where granite gneiss core is surrounded by a 'greenstone' sequence of ultrabasic, basic and sedimentary rocks. Nickel-iron sulphide mineralization occurs discontinuously along one of the basic- ultrabasic contacts. Analyses of unweathered and partly weath- ered rock from diamond drill cores show the ultrabasic rock to be highly variable with re- spect to nickel, copper, cobalt, zinc and manga- nese. Samples of weathered bedrock and over- lying soil were analysed both for total trace element contents and for the trace elements associated with secondary iron and manganese oxides. Approximately 30 per cent of the total nickel content of the weathered basic rock is associated with secondary iron and manganese oxides, compared to approximately 15 per cent in the weathered ultrabasic rock. The soil is partly transported but has a residual component sufficient to provide a reli- able indication of the underlying rock chemistry, although the trace element content of the soil is less variable than that of the rock. Total

Jan 1, 1973

Gold mineralization like other low concentration high value commodities has gained the notoriety of being difficult to sample. This adversely affects the confidence that can be placed in resource estimates and ore reserves. As an example, it is not uncommon to find differences of the order of 30% between duplicates of a single sample sent to two different commercial laborartories. Two halves of drill core generally show marked differences in grade. Again differences of 50% are not uncommon in halved core. In the context of this type of "error" within the base data used for the resource estimate, many of the subtleties of computation methods and expert judgement of resource categories, are almost a case of shutting the gate after the horse has bolted. Managers, financiers and consultants must question the quality of the base data upon which resource estimates are made. They must insist that standard and duplicate samples are used to measure the accuracy and precision of commercial analytical laboratories, that sampling practices have been checked for possible bias and give tolerable repeatability. Further they must ensure there can be a realistic confidence in the estimates by correctly using these measures of data quality to quantify risk.

Jan 1, 1990

By Fiedler VA, Threadingham GM, Leckenby DF, Clarkson CJ

The Utah Development Company Research and Development Laboratory has embarked upon a programme of optimisation of the company's coal preparation plants. This goal is being accomplished in a three-fold manner - use of pilot plant equipment for optimisation and modelling of the various unit operations, evaluation or development of on-stream ash analysis for process control, and evaluation or development of alternative processes. In each of these areas, digital data acquisition- and at a later stage, process control feedback, is being extensively utilised, based largely upon the use of the HP85 and HP9915 desktop computers. A variety of input/output configurations such as HPIB, BCD, GPIO are used, and at times supplemented by microprocessors such as the Intel 80/05 to assist in data transfer. This paper will discuss a number of specific projects, especially in relation to the manner in which the variables are monitored, and the data later retrieved and analysed.

Jan 1, 1983

A nine-month investigation was conducted into the effect on coke quality and blast furnace operation of the addition of bentonite and southern coal to the northern coal fed to the coke ovens at the Newcastle steelworks.Additions of 0·3 per cent bentonite or 25 per cent southern coal to the northern coal increased the coke strength from 15-20 A.S.T.M. stability to 25-30 A.S.T.M. stability. It is likely that improved mixing and blending facilities would, in both cases, give a coke of over 30 A.S.T.M. stability.For the same coke strength, the use of 0 3 per cent imported Wyoming bentonite was considerably cheaper than the use of 25 per cent southern coal, but the use of Australian bentonite promises the same coke strength for still lower costs. Other additives such as coke breeze, charcoal, iron ore fines, and certain other finely divided materials, gave relatively minor improvements in coke quality.There appeared to be sufficient improvement in blast furnace operation and production to justify full scale addition of bentonite to improve coke quality, although other variables, particularly iron ore physical quality, overshadowed on many occasions the effect of coke quality. Further coke trials with southern or bentonite will be carried out when ore quality has been improved by the introduction of ore sintering at Newcastle.INTRODUCTIONDuring the period of operation of the Newcastle coke ovens and blast furnaces from April 1960 (when No. 3 blast furnace was blown in after rebuilding) to December 1960, a bentonite coke trial was carried out based on earlier research findings (Gregory, 1959a, 1959b; Felton and Gregory, 1960; Gregory, 1960) that as little as 0 3 per cent to 05 per cent bentonite clay added to northern N.S.W. high volatile coking coals gave a significant increase in coke strength. The bentonite coke trial was followed by trials...

Jan 1, 1962

The Coal Corporation of New Zealand Ltd (CoalCorp) is the largest coal producer in New Zealand, with extensive properties in both the North and South Islands. CoalCorp's North Island operations are kilcmetres to the south of Auckland. opencasts, are located in the catchment wildlife, historical and scenic values. in this catchment is the single most mining operations. centred on Huntly, a town some 80 Five coal mines, four of which are of Lake Waahi, a lake with significant The discharges of mine lodgement water important environmental constraint on Throughout New Zealand the use of water is controlled by a statute called the Water and Soil Conservation Act 1967. All industrial water users are required to hold Water Rights, which are in effect licences to take, use, dam, divert or discharge water. Water Rights are obtained through a legally defined process and any potentially affected party has the per to object to their granting. A special tribunal hears the evidence for and against an application, and issues its decision, which is reviewable in a higher court on Appeal. Rights, if granted, are issued subject to conditions and, in the case of mining discharges, limits would be set on flaw rate, suspended solids concentrations, turbidity, pH and the concentrations of any potential toxicants. This paper presents a case study of an integrated, catchment wide water management plan for Lake Waahi, that was prepared by the author, and others while the author was in the employ of CoalCorp, and its predecessor, State Coal Mines. The author is grateful to CoalCorp for their permission to submit this paper.

Jan 1, 1988

This paper briefly reviews the history of mine haulage trucks. It reviews producti- vity limitations with respect to size or speed. Changing haul requirements once again create the need for more flexible mechanical drive power transmission equipment. The new equip- ment however is designed to provide extended life between overhauls as compared with previous mechanical transmissions.

Jan 1, 1981

I am honoured and very pleased to have been given the opportunity this evening to say a few words of thanks not only on behalf of all the guests but especially for the delegates and accompanying persons attending the 13th Congress of the Council of Mining and Metallurgical Institutions. Firstly, I would like to congratulate Sir Hamilton Whyte,KCMG for his most interesting address. In his far ranging talk, when he showed knowledge of widely diverse subjects, I had a brief fear that he was going to be talking about the details of support methods in deep level mines, or how to avoid flotation problems in multi-metal mines. Although he did not go that far, he touched on subjects which have arisen this week - long term planning and secure supply of minerals at acceptable prices. The dire predictions of the Club of Rome have been debunked with a far more elastic supply of minerals having been proved. Combined with the importance of a falling birthrate in some parts of the world, this will lead to many changes in the future, when hopefully governments will take the long term view rather than look at the next budget or the next election. Maybe some of them are not too lazy to do this for all of us. However as a fellow Ukranian, I feel that he might have been called something different if he had been in Australia. Sir Hamilton, thank you for your talk. Once upon a time - and this is not a fairy story - there was a cobbler who had two sons; one very bright who became a professor of mathematics; the other, dim, who became a millionaire shoemaker. Asked for the secret of his success, the millionaire attributed it to a vital piece of economics which his father had imparted, "Be content with small margins on a large turnover." "So", said the millionaire, "I make my shoes for $2 a pair and sell them for $5. I am very happy with the three per cent profit."

Jan 1, 1986

As part of its Concentrator operation Hamersley Iron Pty. Limited uses wet high intensity magnetic separation to upgrade shaley low grade ore in the minus 0.5mm size range. Materials handling problems, largely caused by fine ore types and design deficiencies, surfaced in the Fines Treatment Plant soon after Concentrator commissioning in 1979. Surging throughout the circuit impaired process efficiency and added to problems caused by capacity and process control limitations. In 1981 extensive modification works were initiated to supplement minor changes made to that date. The new circuit significantly increases capacity and provides greater process control.

Jan 1, 1978

The O.K. deposit occurs within a belt of cherts and spilitised basic volcanics near the western margin of the Hodgkinson Province. The tabular to lenticular shape and gross conformability of the ore bodies; the common occurrence of colloform, framboidal and banded textures in the ores; the lack of significant alteration adjacent to the massive ore horizons and the apparent restriction of stockwork mineralization to the foot-wall side of the massive ore zone at the O.K. mine, all favour a syngenetic origin for the massive sulfide bodies. Furthermore, the micro- structural evidence suggests that the ores have undergone the same deformational history as the country rocks. The invariable association of the ores with spilites; the S isotope values and Co-Ni contents of the pyrites, together with the primitive metal assemblage (Fe, Cu, minor Zn) strongly favour a basic magmatic source for the sulfides. It is suggested-that the sulfides were probably precipitated sub aqueous- ly during a hiatus in volcanic activity. The O.K. deposit is of the cupreous pyrite variety, but unlike other well known occurrences of this type, it does not con- stitute part of an ophiolite complex. While the host volcanics exhibit strong ocean floor tholeiitic affinities, no associated ultra

Jan 1, 1978

By D Obeng, D Alexander

Over the past five years, commodity prices have been high and the focus of many plants has been æthe more metal the better, at whatever costÆ. In the recent economic crisis, the focus has shifted more to reducing the cost of production and operating at higher efficiency. Since 2002, JKTech has partnered with the Century mine in north-west Queensland to transfer technology and understanding through the good, bad and ugly economic environments, using methodology and techniques arising from research at the Julius Kruttschnitt Mineral Research Centre (JKMRC) and other research institutions around the world as part of the AMIRA International P9 Project. The JKTech studies were concentrated around the primary zinc circuit. During this period, Century expanded the primary zinc regrind capacity, installed additional scavenging capacity, installed and commissioned a Jameson cell for concentrate cleaning in the carbon preflotation circuit, and installed additional primary grinding capacity. Flotation circuit models were developed for each of the survey campaigns and enabled opportunities for further improvement to be identified, implemented and tested in the subsequent campaign.

Jan 1, 2009