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Project developent proceeds by increasingly detailed studies addressing overall project returns through an analysis of the substance, risks and costs associated with the following elements: ò Reserves ò Mining ò Processing ò Infrastructure ò Environmental Impact ò Product Market Computer-based expertise has a potential to ò Capture perishable expertise, making this available for shared access and so reducing the cost of human experience ò Consolidate know-how for optimising process operations, bringing consistency of judgement and advice to decision- making by making the rules, facts and preferences explicit ò Allow assignment of the basis and authority of decisions, so experts can pass routine expertise down the line, freeing their time to generate more. ò Force a review of expertise when creating the knowledge base.

Jan 1, 1989

Tumbling mills and some theoretical and practical aspects of milling are discussed. Attention is directed towards the difficulty of relating the dynamical analyses of the motions of particles within mills to the existing treatments of breakage processes. This synthesis may be advanced by a study of milling that utilizes the matrix analysis of breakage processes. Application of the matrix analysis to results obtained on (i) grinding in open-circuit a zinc ore in a conical pebble mill and in a modified conical mill, (ii) "grinding of cement clinker in a compound mill, and (iii) to some drop-weight grindability tests is discussed. It is shown that the 'IT-breakage model adequately describes the breakage processes of each of the tests. (The proportion broken in each breakage cycle is given by 'IT and is independent of particle size.)The size distributions of the products are accurately predicted in the cases considered. Matrix analyses of the breakage of coals, various ores and a cement clinker have been made. Appendices give an elementary account of the matrix methods and give the equations fully describing reverse order closed circuit operations. The matrix analyses of breakage processes and the survey are used to examine briefly closed circuit grinding.INTRODUCTIONTumbling mills are slow-speed crushing and grinding machines which have been developed from some fairly simple types into many widely differing forms. Many of these versatile mills have proved extremely useful in ore dressing and mineral beneficiation, whereas others have been used in the cement industry and less extensively in the coal industry.The performance of even the simplest tumbling mill is very imperfectly understood, whilst the more difficult problems associated with the balancing of complex milling circuits and with the establishment of the optimum operating conditions for the whole of a complex circuit are even less well apprehended.Our knowledge of the performance of tumbling mills is rather sharply divided into two categories: the first consists...

Jan 1, 1957

In setting out to describe the methods and machinery employed at Iron Knob the writer does not attempt to give any information as to the situation, topography or geological features of the locality. This, together with estimates of the quantities of ore still available, has been carried out in a most thorough manner by R. L. Jackr and F. R. Hockey. This essay is intended to deal with working methods as they exist to-day, beginning with drilling, blasting, quarry traction, etc., and touching on such details as the supplyof electricity, water and compressed air.At the present time almost the entire output of ore is won from the hill known as Iron Monarch. The form of the hill, a smooth, rounded dome, rising some 640 ft. above the plain and having a base diameter of n miles, lends itself ideally to the "bench" system of open-cut quarrying.Fig. 1 shows the relationship of the benches "A," "B" and "E" in their order of development. Bench "E" is at present the principal working, but, as the greater part of the ore above this level has now been removed, bench "A," some...

Jan 1, 1936

By P Rowe

New Zealand Steel's Taharoa titano-magnetite mine, south of Auckland, set two national load records when it transported around 2000 t of mining equipment three kilometres overland on time, under budget and without safety incident. It was the first time in New Zealand that four platform trailers were assembled end-to-end to transport a load. It was also the first time that a single load of 1000 t was transported on platform trailers. The need for the relocation of all equipment was realized five years ago. It took two years of planning and specialist advice to relocate the mine's 250 t dredge, 500 t surge bin, 1000 t concentrator plant and ancillary equipment from the Southern Mining Region across a specially designed haul road to the Central Mining Region. The project was carried out during a six-week shutdown in early 2001. Two dry docks were constructed, one at each end of the relocation route. The equipment was floated into a dismantling pond that was interconnected with the dry dock in the Southern Region. Through pumping, the water levels were controlled to allow transfer of the separated units from the dismantling pond into the dry dock. Once drained, sets of self-elevating platform trailers were used to transport the main units, one at a time, between the dry docks. Five prime movers were used to pull the loads. At the receiving end, the units were off-loaded in a dry dock interlinked with ,the first mining pond. The equipment was relocated because the reserves in the Southern Mining Region were mined out. A natural watercourse û the Wainui Stream û defines the northern boundary of the Southern Region and the objective became to relocate the mining plant to the other side of the stream and re-establish in the Central Region. The project team selected the trailers as the most effective means of transporting the equipment, particularly given the non-invasive means of crossing the Wainui Stream. Negotiations with prime contractor Tranzcarr Heavy Haulage Ltd commenced in mid-2000. The remainder of 2000 was spent in developing concepts with the contractor, detailed designing, preparing the dry docks, haul road and initial mine plan for the Central Region. These activities occurred with no conflict to the normal site production.

Jan 1, 2001

Flotation Circuit Optimisation - Towards More Sustainable Practice

Sep 13, 2010

The variation of carbon monoxide and hydrogen utilization with the amount of the reductant in the blast furnace bosh gas was investigated for the No. 4 blast furnace at The Broken Hill Proprietary Co. Ltd.iron and steel works. Newcastle. The degree of CO utilization decreased with increasing CO in the bosh gas; the H., utilization increased with the H., content of the gas. Empirical relationships for CO and H., utilization are proposed.H2, is 3-6 times as effective a reductant as CO at present levels of CO (34-39 per cent) and H2 (6-10 per cent) in blast furnace bosh gas. H2, gas injection into the blast furnace is proposed as a means of lowering the coke consumption, and the economics of H2 injection are evaluated.

Jan 1, 1975

The Morley Coal Measures (Upper Cretaceous) at Ohai Coalfield were deposited in an intermontane basin alluvial environment of entirely terrestrial aspect. Within this regional setting, three distinct types of depositional environment are recognised; these are: (i) a sand-dominated (South Saskatchewan type) braided river system characterized by channel-bed dunes and possibly compound bars; (ii) a well-drained floodplain environment frequently subject to crevasse-splay and overbank-flow sedimentation; and (iii) a poorly-drained, commonly peat-accumulating backswamp environment locally traversed by tributary drainage systems and occasionally inundated by crevasse splays and overbank flows. All major coal seams of the Morley Coal Measures originated within forest moors under predominantly telmatic (periodically inundated) conditions. The peat-forming vegetation comprised largely arborescent forms (dominantly conifers), in addition to pteridophytes and bryophytes. In-seam vertical variations in coal type indicate groundwater levels initially decreased and then increased during the lifetime of a particular peat swamp, possibly in response to a change in the migration direction of an adjacent fluvial system. The proposed depositional model for the Morley Coal Measures has the potential to be utilised during exploration programmes and mine development to impart greater objectivity to predictions concerning seam geometry and continuity, trends in coal type and quality, and likely roof and floor conditions.

Jan 1, 1985

By Both R. A, Daily B

The Patawarta Diapir, located in the northern Flinders Ranges (South Australia), has intruded into late Proterozoic Wilpena Group sedimentary rocks. The diapir contains disrupted blocks of a wide variety of rock types, most of which can be correlated with the Lower Callanna Beds of Willouran age, in a matrix of predominantly carbonate and siltstone breccia. Mafic rocks in the diapir appear to predate intrusion of the diapir. As with many other diapirs in the Flinders Ranges, copper mineralization is present in the diapir and occurs as narrow veins consisting essentially of carbonate with chalcopyrite and pyrite that formed after diapiric intrusion.Fluid inclusion studies demonstrate that the mineralizing fluid was a Na-Ca-K-Cl brine; probably derived by expulsion of interstitial water following emplacement of the diapir, with dissolution of evaporites within the Callanna Beds sediments and enrichment in copper by reaction with these sediments and associated basic igneous rocks. Mineral assemblages combined with fluid inclusion and geochemical data indicate a possible environment of vein formation of T ÿ 165°C, pH ÿ 4.3 ± 0.9 and log fO2 ÿ -47.3 ± 0.5. Sulphur isotope analyses indicate d34Sfluid ÿ 10 per mil, suggesting evaporites in the Proterozoic sediments as the major source of the sulphur but with some additional sulphur from an igneous source, possibly leached from the malic rocks of the diapir.

Jan 1, 1986

An optical computing system was used to determine spacings and frequencies in geological fabrics and engineering joint fabrics.Three-dimensional arrays of joints were plotted on an equal-area net. Directions in which true spacings are seen were determined from these plots. Photographs taken along these directions were used for optical computing.

Jan 1, 1970

The following notes apply more especially to the purchase of silverlead ores produced in the neighbourhood of Zeehan and Dundas; for it is this class of ore that is principally mined in those parts, and which creates competition among the ore buyers.In the early days of this field, most of the ore passed through the hands of the first buyer who had sufficient enterprise to establish himself at Zeehan but in more recent times, competition has been so keen that there are generally three or four buyers tendering. lf the output was large this would not matter so much from the buyers' point of view but when we consider that the output of the field is only some 1,650 tons per month, and that of this 70 odd tons are produced by the Western and Montana mines, aud being sent home for realization, is withdrawn from local purchasers, there is really not enough for four buyers, especially at the present exorbitant prices they pay the miners.Some of the mines have a fixed sampling day, on which it is tacitly understood that the ore buyers will attend. Others, such as Grubb's Silver Mining Oompany, No-Liability, send round a printed reminder, stating the quantity of ore, and the date of sampling.

I would take this, opportunity of thanking you for the high honour you have conferred on me in electing me to the responsible position of President. You may rest assured I will use my best endeavours to promote the interests of the Institute in every way that lies in my power. In reviewing the work of the past year, it is a matter for congratulation to find the Institute in a position at once so healthy and robust, and that notwithstanding the acute depression which has prevailed in the mining industry.Owing to deaths or departures from the colony, the names of six members have disappeared from the roll of membership, but you will be pleaed to learn that several new members have been elected, the register now, showing 56 Members, 25Associates and 2 Students. A complete record of the papers read and the discussions that took place will be found embodied in the splendid volume of Transactions which has just been issued, and which I am sure will be welcomed by mining engineers in all parts of the world.

Jan 1, 1901

By P C. Couper, P C. Keall, S J. Mathews, A Francis

An epithermal gold-silver deposit is presently being developed at the Golden Cross Mine in the Waitekauri Valley, 8 km northwest of Waihi, New Zealand. Highest grade mineralisation underground is mainly confined to an elongate zone of strongly banded quartz veining on the hangingwall. Footwall veining is irregular, flatter lying, and of lower grade. Hydrothermal breccias in the ore zone may have economic grades where clasts of vein quartz are present. Jigsaw breccias, shingle breccias, and layered breccias with sedimentary type structures such as layering, crossbedding, and graded bedding have been identified proximal to, and within, quartz veins. Mineralisation in the open pit occurs in and adjacent to stockwork quartz veining.   Three alteration zones are recognised: a central silicic zone enclosing Au-Ag bearing quartz veins, an argillic zone above the stockwork zone and in the footwall of the underground ore zone, and a propylitic zone which is gradational with argillic zone. Intense shearing is confined to the less competent argillic zone.   Precious metal mineralogy consists of electrum (65% Au; 35% Ag) and argentiferous tetrahedrite, polybasite, pyrargyrite, argentite, and native silver. Pyrite is the dominant sulphide mineral. Marcasite, arsenopyrite, and rare chalcopyrite and sphalerite also occur. Oxidation ranges from a few metres in the argillic western stockwork zone to 100 m in fractured rock in the footwall of the stockwork.   The open pit contains a proved and probable reserve of 2.1 million tonne grading 3.5 g/t Au and 17 g/t Ag. The underground mine will produce 2.7 million tonne grading 7.8g/t Au and 27g/t Ag.

Jan 1, 1991

The leaching characteristics of a number of Australian uranium ores were determined under acid and alkaline conditions. Ores from the Ranger, Nabarlek and Koongarra deposits in the Northern Territory were readily leached in dilute sulphuric acid. Suitable processing conditions were: leaching at 35-40°C, pH 1·52·0 and redox potential -475 mV for periods of 16-24h with ore ground to 50 per cent -200 mesh CB.S.S.). Ore from the Roxby Downs deposit in South Australia required leaching at 55°C and a redox potential of -650 mV to achieve a satisfactory recovery. All ores contained refractory minerals which were not leached under conventional conditions, limiting uranium extraction to 86-96 per cent.Carbonate leaching of carnotite in calcrete ores from Yeelirrie and Lake Way in Western Australia yielded uranium extractions of at least 98 per cent. Leaching rates were considerably faster than those reported for other applications of alkaline leaching as the slow oxidation step was not required.

Jan 1, 1979

Rutile Beach Sand from Hard Rock

Sep 13, 2010

The Greymouth Coalfield contains New Zealand's greatest known resource of bituminous rank coal. The coals are of very high quality, with low ash and sulphur contents and a range of other properties that makes them desirable for a wide range of uses. In fact only a few producers around the world today can offer coals with such exceptional properties. This suggests that Greymouth coal has potential as a premium export trading commodity. These assertions have been largely confirmed by a comprehensive exploration drilling programme funded by Mines Division û Ministry of Energy between 1979 and 1984. The program, forming part of the NZ Coal Resources Survey, was carried out under contract by Lime and Marble Ltd. The drilling of 49 deep, predominantly cored, holes at 1000 m intervals over the coalfield has generated a vast amount of data. It has shown the existence of three major potentially minable coal deposits containing 233 x 106, 33 x 106 and 15 x 106 tonnes of coal in ground. Investigations have at this stage only identified targets and these estimates represent 'in ground' resources, not recoverable reserves. Recent geological studies as well as past and present mining have clearly highlighted the problems posed by the complexity of the coalfield geology. The coalfield lies within a mobile zone in the earth's crust known as the Paporoa Tectonic Zone, which has been active from at least mid-Cretaceous to the present time. Currently this factor poses the greatest obstacle to the determination of mining possibility of the, defined deposit and ultimately will strongly influence any future mining development. The Greymouth Coalfield has, however, had a long and eventful mining history spanning the last 120 years, where 32.5 x 106 tonnes of coal has been won from over 100 mines. In spite of the problems facing development, the large quantities and exceptional quality of the remaining coal will act as a strong inducement to persevere with this difficult but potentially valuable resource.

Jan 1, 1985

By A Prinsloo, R Tewu

Automatic control of semi-autogenous grinding (SAG) mills has often been considered complex. Recent experiences at Century Zinc (worldÆs second largest open pit zinc mine) refute this. Together with operating knowledge and appropriate control techniques high quality control is achievable. In this application model-based, constraint, and multiple output control were employed. The control was implemented using standard blocks in the plant DCS. The resulting overall control strategy fulfils the operating objectives and controls the mill with minimal operator involvement over 95 per cent of the time. Previous campaigns using expert systems and complex DCS based control have lacked durability. Their fall into disuse is briefly discussed.

Jan 1, 2009

The Wamum and Idzan Creeks Prospect, located 79km W of Lae, Morobe Province, Papua New Guinea (PNG) was discovered by the exploration arm of Conzinc Riotinto of Australia Pty Ltd (CRAE). The detailed surface exploration and 11 vertical holes drilled by CRAE, combined with the recent work by Highlands Gold Limited, indicate the occurrence of porphyry copper-gold mineral- isation and associated alteration. The prospect occurs within andesitic volcanics of the Middle Miocene Langimar Beds. It is bounded by NE trending faults to the NW and SE. The alteration and mineral- isation is hosted in the andesitic tuffs adjacent to high level quartz diorite and hornblende diorite stocks. A NW trend to alteration and mineralisation is obvious in Wamum and Idzan Creeks. The main alteration type is propylitic with minor zones of potassic alteration. A late sericite-quartz-kaolinite-pyrite alteration overprinted the earlier alteration and mineralisation. Copper and gold mineralisation is related to a quartz-carbonate-chalcopyr-ite-pyrite (¦ bornite) vein stockwork and biotite ¦ K-feldspar alteration. The mineralisation system at Wamum and Idzan creeks is low in total sulphides. It is considered as a high- level fracture-controlled system with limited low grade Cu-Au mineralisation.

Jan 1, 1991

By N Phillips

Fosterville gold mine recently celebrated production of its one millionth ounce of gold based firmly within a history of refractory sulfide gold mining. Compared with other Victorian gold mines, the disseminated nature of the sulfide gold is a deposit style with low estimation variance combined with established processes to accurately delineate the controlling structures. The systems in place had been established and have worked effectively for the majority of the one million produced ounces.By the end of 2014, diamond drill campaigns targeting the lower Phoenix orebody at depths of 800 m below surface began showing a change to the nature of the gold within the deposit. Coarse visible gold within 0.5–2 m thick quartz carbonate veins were being intersected with regularity showing the emergence of a different zone of gold mineralisation.Data about the new and exciting discovery couldn’t be gathered fast enough, however, established systems and processes throughout the geology and processing departments were not developed to handle a coarse gold environment. Change would be commensurate with the size and scale of the discovery, and new learnings would need to be implemented quickly to keep in front of a mining schedule that was focused on producing tonnes due to the dropping grades of the sulfide ore.Gold assays being returned were showing that the gold nature was different to those of other Victorian deposits. Comparative to the highly nuggety nature of gold found in other Victorian goldfields, the fine grained gold accumulations were dispersed in relatively consistent narrow linear trends grading consistently into the hundreds of grams per tonne. New drill intersections were being returned by the day and research to find developed orebodies that had published information into how to handle such a rapid change yielded few examples.The challenge was to review and set new standards with regards to handling an orebody that transitioned the very nature of the gold being mined. This involved reviewing all steps in the estimation process including data capture and quality control and quality assurance through to mineral liberation through the mill. Difficulties also involved finding analogous orebodies that consisted of both free milling and refractory ores that were dealing with drill assays that were measured as percentages of gold.CITATION:Phillips, N, 2017. Fosterville gold mine – breaking the mould for Victorian gold, in Proceedings Tenth International Mining Geology Conference 2017, pp 393–400 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By Caithness SJ, Heape JMT

Following the discovery by CRA of gold at Mt Kare, and the subsequent 1988-90 gold rush, mechanised mining of the alluvial resource is now being carried by a company jointly owned by CRA (51%) and landowners of the area (49%). Mining is currently being carried out using small gravity processing plants fed by hydraulic excavators. Use of hydraulic mining techniques will be limited to over- coming difficulties related to the high clay content of the material and the soft nature of the bedrock. Current resource estimates suggest that the alluvials will have a mining life of three to four years. During this time, exploration of the hydrothermal gold mineralisation at Mt Kare will be carried out by a wholly-owned company of CRA. It is hoped that this will lead to establishment of an economic primary gold resource.

Jan 1, 1991

By P M. Hancock, Associates

Lacustrine sediments, hydrothermal explosion breccias and spring precipitates deposited 5200 - 1800 years BP as a result of geothermal activity at Lake Rotokaua, contain New Zealand's largest known sulphur reserves. Current drill indicated reserves are 2 600 000 tonnes of elemental sulphur, assuming a ten per cent (dry basis) cut-off, contained in some 17 000 000 tonnes of ore with an average grade of 214.0 per cent (dry basis) sulphur. Additional inferred ore containing 500 000 - 900 000 tonnes of sulphur has yet to be prospected by drilling. Geological factors will be important in exploitation of the deposit, particularly the extent and disposition of the orebody, sulphur grades and distribution, physical characteristics of the ore, permeability and stability of the overburden and the nature and extent of geothermal activity in the area. Trials to date indicate that Frasch mining and possibly opencutting are unlikely to be successful mining methods. Further mining feasibility studies will be required to ascertain the most likely mining system for the deposit.

Jan 1, 1984