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Alluvial gold mining in New Zealand and in particular on the West Coast underwent a renaissance during the early 1980's. This was based on two main factors: a) the sharp rise in the gold price b) the advent of the hydraulic excavator with which to mine the auriferous gravels. The scale of operations varies considerably. A small operation typically consisting of one or two people using an excavator to feed either a land based or pontoon mounted (floating) gold recovery unit, which will typically feature a rotary screen with or without a tailings stacker with the screened fines < 10 - 15 mm) fed over riflle tables. The largest screening plants of this type are operated by DML Resources in their Arahura and Mikonui mining operations where the plants have the capacity to screen up to 250 m3 of gravel per hour. These plants usually employ jigs and centrifugal concentrators for gold recovery. Unique amongst current operations is the Grey River Dredge, a bucket ladder dredge capable of processing 700 m3 per hour similar to those that operated earlier this century. Gold concentration is by a series of jigs. The number of plants operating in recent times peaked at around 130 in 1987 (coinciding with a nominal average gold price of $751) and since that time has steadily declined to 80 units in 1993 and about 45 - 50 units today. This cycle of rapid expansion and then steady decline has been repeated on the West Coast since the original gold discoveries in the mid nineteenth century.

Jan 1, 1996

By S Jokanovic

At New Zealand Steel MiningÆs Waikato North Head operation a Bucket Wheel Excavator û shiftable conveyor mining system is used to excavate titanomagnetite bearing sand and clay. The system utilises two Bucket Wheel Excavators and two Beltwagons with a two shiftable bench conveyors and two common trunk conveyors to deliver material to a processing plant. The original system was commissioned in 1984 as a high capacity, low cost method of excavating. In 1996 a second Beltwagon was purchased, increasing the flexibility of the mining system.

Jan 1, 2002

By G S. Lane, G D. Richmond, J Dioses

This paper discusses the methods used in the design of flotation plants, including benchscale batch and locked cycle tests and pilot plant trials. Two case studies are presented, one for the Cadia Hill Gold Mine and the other for the Hellyer copper, zinc and lead plant. These case studies present different problems with widely different target grind sizes, liberation characteristics and HellyerÆs sequential flotation circuit versus CadiaÆs æsimpleÆ copper/gold flotation circuit. They have a common theme in that pyrite forms the principal floatable concentrate diluent. Hellyer ore contains finely disseminated chalcopyrite, sphalerite, galena, and tetrahedrite. The flotation plant design was based on extensive benchscale testwork (including locked cycle tests) on drill core and many months of operation of a 30 tonne per hour æpilot plantÆ, using the old Cleveland Tin Mine process plant suitably modified for the duty. The Cadia concentrator was designed on an extensive benchscale variability testwork program, approximately a dozen locked cycle tests conducted on drill core and two weeks of continuous pilot plant trials on three separate samples obtained from an adit into the orebody. The orebody is a monzonite porphyry with disseminated chalcopyrite/bornite/pyrite of very low grade (0.17 per cent Cu, 0.73 g/t Au). Methods used to establish the appropriate flotation circuits for the treatment of the Hellyer and Cadia ores, as well as the interpretation of the testwork data, are discussed in this paper. Plant performance is reviewed in the context of predicted versus operational performance.

Jan 1, 2002

The Winton Basin is one of three Southland sub-basins. The oldest known sediments are Early Oligocene terrestrial shales, sands and lignites deposited in half grabens formed as a result of oblique extension. A marine transgression in the Oligocene deposited mid-outer shelf to upper bathyal mudstones. Shallowing of the basin and tectonic quiessence lead to limestone deposition in the Early Miocene. Regional tilting led to uplift in the north and east and deposition of terrestrial lignites and gravels across the basin and the basement high to the south.

Jan 1, 1992

By Litvinenko V. I

Being a source of structural materials for many centuries, the modern image of the ferrous metallurgy is burdened with obsolete technologies with disregard towards new environmental protection requirements. The production cycle of metallurgical products have two clear-cut stages: I . production of liquid metal and casting into steel billets; and 2. processing of steel billets in solid state under high temperature to produce various shapes and profiles of metal products. Plastic deformation of metal at the second stage is least associated with environmental pollution and is presently being provided with more and more advanced equipment.

Jan 1, 1999

The labour question is one that has caused mine managers much thought and anxiety and is likely to continue to do so as long as human beings exist. The difficulty is to devise some arrangement whereby the interests of miner and mine ownerare identical. Mines cannot be worked without capital, and capital is no good without labour, yet, though both have the mine in common, their interests are not exactly the same. Some men are happy so long as they can scrape through by exerting themselves as little as possible, but capitalists do not work mines for charity, they want some return for their money.Where a large number of men are employed there are bound to be examples of all sorts, good and bad, and it is because one cannot depend on all, that different methods of employment have to be adopted. Which method is selected depends to a great extent on the labour market, local conditions, nature of the ore and the way in which it occurs.A big step towards success is obtained by securing the services of good bosses, not only those who know how work should be done, but men who have a knowledge of human nature. It is a big mistake to be too lenient with a man, also to be unnecessarily harsh. A good boss will always be sought out by good men who have worked under him before, or who have heard of him from others. By a good boss we do not mean one who employs two men where one would do, or who lets the men loaf...

Jan 1, 1901

By G P. Taylor

Mining Lease SML 57 was registered to Mount Kasi on 5 January, 1995. The Mount Kasi gold mine is located in Vanua Levu, Fiji's second largest island and operated from 1932 to 1946 producing 261,000t of ore at an average grade of 7.5g/t Au. The deposit represents a structurally controlled style of high sulphidation copper gold mineralisation with peripheral low sulphidation mesothermal vein type gold mineralisation. The resource consists of 1,048,000 tonnes of residual soils (eluvium) containing 1.9 g/t Au at 0.5 g/t Au cut off and 1,240,000 tonnes of hard rock at 3.0 g/t Au and 1.0 g/t Au cut. 94 drill holes, 298 auger holes and 85 pits were modelled to outline the resource. 29% of the pits bottomed in mineralisation and it is likely the full thickness of eluvium has been understated. The pit is scheduled to produce 500,000 tonnes of ore per annum to yield 35,000 ounces of gold with an initial 2 years of eluvial ore followed by a further 2 years of hard rock ore. Total capital costs are estimated to be less than 10.0 million dollars with construction planned to commence in 1995. The likelihood of locating further ore is high.

Jan 1, 1995

Important factors in dredge design are the estimation of total head, and the determination of flow in and around suction nozzles and in pipe lines. Total head for the dredge pump is calculated from velocity, static, and friction heads. Flow into suction nozzles depends on whether hydraulic jets or mechanical cutters are used, and on nozzle shape. Design of pipe lines depends on the transportation characteristics of the pulp, skin friction, swirl, and the avoidance of cavitation. Measurement and control of flow is important.INTRODUCTIONEconomic deposits of heavy minerals along the east coast of Australia occur in frontal dunes, which are normally unconsolidated and granular, or in hind dune areas which may contain indurated seams interspersed with loose material. In working frontal dunes, dredging depths are usually shallow since values do not persist for more than a few feet below sea level. However, the controlling factor in dredging the hind dune areas is the level of the water table and suction dredges may be designed to mine to depths of 120 ft, or even more, if necessary.In previous applications of suction dredges in the industry attention was directed primarily towards production and there was only limited research on fundamental techniques. However, with lower grade deposits now forming the major ore reserves, production levels and profit margins will fall unless more efficient dredges are developed.For satisfactory design of dredges it is essential that the total head be accurately estimated and that detailed information of the principles of flow in and around suction nozzles be determined. This paper presents information gained from field experience and laboratory investigation on these aspects.

Jan 1, 1962

Perhaps one of the most important conferences or symposia which our Institute has conducted, was the joint Aus. LM.M./AJ.M.E. meeting held in Canberra in May 1978, with the theme International Resource Management (Woodcock, 1978).We were privileged to witness active participation in the meeting by outstanding personalities from the mining and metallurgical industries of Australia and New Zealand, the United States of America, Canada and the United Kingdom and to hear addresses on subjects of international significance to the mining and metallurgical industries.Our Institute is one concerned with professionalism.The principal objects of The Institute as described by our founders include, "promoting the arts and sciences connected with the economical production of the useful minerals and metals, and the welfare of those in the industries, by meetings for social intercourse, and the reading and discussion of professional papers, and to circulate by means of publications amongst its members and associates, the information thus obtained".Sir Maurice Mawby (1968) said in his Presidential Address to the Institite, "the most important aspect of these objects was the promotion of the arts and sciences of the mining industry".Why is it then, that a large proportion of the papers given at the meeting in Canberra dealt with world wide social aspects of the mining and metallurgical industries, rather than the technology, the arts and sciences of mining and metallurgy as principal factors in international resource management?The answer is quite simple of course, and that is that the social and political factors are the principal factors which create the demand for basic raw materials and in the long term determine the costs and prices of the commodities which our professional abilities are drawn upon to produce.

Jan 1, 1979

The paper is a general review of practice in design of sub-level open stopes in Northern Rhodesian copper mines and gives examples of some interesting developments during the last five or six years. It discusses the effect of hangingwall subsidence and the methods used to combat rock pressure on working areas.INTRODUCTIONAll producing mines on the Northern Rhodesian Copperbelt have large ore reserves and are designed for high rates of production. The three mines (Mufulira, Rhokana Corporation, and Roan Antelope) where sub-level open stoping is used, hoist from 250,000 to over 400,000 short tons of ore a month so that any stoping method used must be adaptable to concentrated' mining. Individqal stopes produce from 5,000 to over 25,000 short tons of ore a month.Structure af the ore bearing sediments is simple; faulting in ore is almost entirely absent and copper mineralisation is found in the same beds over great distances...

Jan 1, 1954

Crocidolite deposits in the Hamersley Ranges, NW. of Western Australia, occur over a length of 180 miles and a width of 20' to 30 miles. Their stratigraphic environment and mineralogy is comparable to that of similar deposits of the Cape Belt, South Africa. It is probable that the known exposures' represent only a small portion of the total extent.Current production is wholly by Australian Blue Asbestos Pty. Ltd. at Wittenoom Gorge and has been in the order of 1,2,000 to 14,000 long t.p.a over the past six years.INTRODUCTIONThe Hamersley Ranges are located in the NW. Division of Western Australia and extend, approximately, from latitudes 21° 30' to 23°S and longitudes 117° to 1200 E. Their mean height above sea level is 2,000 ft, and they rise from 600 to 800 ft above the general level of the tableland which extends SE. from the coastal town of Roebourne.Mt. Bruce, the highest peak, is 4,024 ft above sea level. The ranges are intersected by numerous north-flowing streams, which are dry during the greater part of the year. These streams have carved deep gorges, and it is in these that the principal deposits of crocidolite outcrop.The presence of the mineral was first recorded in 1917, but the deposits remained untouched until 1937 when strong market demand for crocidolite resulted in considerable prospecting and mining activity, particularly in Yampire, Wittenoom and Dale's Gorges. It was established also that the blue asbestos belt extended from Willi Wolli Springs NW. to Millstream station, Le., over a length of 180 miles and a width of 20 to 30 miles. A number of attempts were made to develop and treat the Yampire and Wittenoom...

Jan 1, 1964

By A Harris, N Fitzpatrick, F MacCorquodale

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Gosowong epithermal Au-Ag deposits, located on the island of Halmahera, North Maluku Province, Indonesia, are owned and operated by PT Nusa Halmahera Minerals, a joint venture between Newcrest Mining Limited (75 per cent) and PT Aneka Tambang Tbk (25 per cent).The Gosowong deposit was a greenfields discovery in 1994. Subsequent brownfields discoveries, most recently in 2009, have resulted in a total endowment of more than 6 Moz Au. The three main deposits include Gosowong, Toguraci and Kencana, and as of December 2013, production comprised 5.7 Mt Au at 24 g/t for 4.3 Moz with remaining resources of 4.2 Mt Au at 13 g/t for 1.7 Moz.Mineralisation primarily occurs in multistage veins, breccias and stockwork veins, with at least four texturally- and mineralogically-distinct vein events, including: banded crystalline quartz, quartz-adularia, quartz-chlorite and quartz-sulfide stages. Vein mode, texture and mineralogy are zoned around areas of maximum dilation, vein width and vein grade. Within banded quartz-chlorite, grades of >1000 g/t Au are common. Anomalous Au-Ag-Pb-As-Sb-K-Li geochemistry in rocks is commonly associated with the epithermal mineralisation. Four major types of hypogene alteration are recognised at Gosowong: silicification (quartz-illite-adularia-pyrite) within the immediate vein zone, argillic (illite-quartz-pyrite) alteration enveloping the vein zone, advanced argillic (dickite-kaolinite-quartz) alteration above and adjacent to the vein zone and within the overlying Kayasa Formation, and propylitic (chlorite-epidote-albite-calcite-pyrite) alteration within the footwall and distal to the vein zone.CITATION:Fitzpatrick, N, Harris, A, MacCorquodale, F and Wardiman, D, 2015. The Gosowong goldfield – a world-class epithermal gold-silver district in Indonesia , in Proceedings PACRIM 2015 Congress, pp 235–242 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By B B. Du, Y N. Lu, L X. Wang, S L. Wu

The cohesive zone in the blast furnace is largely affected by the softening and melting behaviour of ferrous burden because of its vital role in the blast furnace process. The Visual High Temperature Methodology (VHTM) has been given to study the softening and melting behaviour of sinter, two kinds of lump ores and acid pellet intuitively. Before softening, both two kinds of lump ore swelled and more serious for lump ore B because of its denser structure than lump ore A. The softening and melting temperature intervals are different from one another and this phenomenon contributed to the gas permeability of ore layer in the cohesive zone since the ‘ore window’ has formed. Besides, the softening and melting behaviour of mixed burdens have been studied, where it has been found that the softening and melting characteristics of mixed burden A (consisting of sinter and lump ore A) is better than mixed burden B (consisting of sinter and lump ore B) and mixed burden C (consisting of sinter and acid pellet) despite the poorest characteristics of lump ore A. The reason is that the high temperature interactivity between lump ore A and sinter is much better than lump ore B and acid pellet. The high temperature interactivity is mainly influenced by the chemical compositions, porosity and contact condition. This paper provides a new research method for the softening and melting behaviour of iron ore and an important technical basis for the optimisation of blast furnace burden.CITATION:Wang, L X, Wu, S L, Lu, Y N and Du, B B, 2017. The softening and melting behaviour of single and mixed iron ore burdens, in Proceedings Iron Ore 2017, pp 605–610 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Australia's iron ore industry is entering a challenging period with the development of new orebodies, the introduction of new products and the push for further downstream processing. In addition, the recent price reductions for iron ore exports have intensified the focus on reducing capital and operating costs. To assist in these areas, CSIRO is expanding its research capabilities, including the incorporation into CSIRO of the Mineral Processing Laboratories in Perth, which were previously managed by the WA Department of Minerals and Energy. In addition, a large part of the $24.4 million expansion of CSIRO's Pinjarra Hills laboratories in Brisbane will be devoted to enhancing iron ore processing research, providing purpose built laboratories and large process bays.

Jan 1, 1999

By Madgwick J. C

Microaerobic biodegradation oflow-grade manganese dioxide slurry tailings was demonstrated in enrichment cultures treated with dilute molasses at 30°C and pH 5·8. Supplementary nitrogenous nutrients, yeast extract addition and pH adjustment were not required.Continuously stirred, air-limited reactors were superior to still intermittently agitated cultures, in that, at 5 per cent (w/v) MnOz tailings and 5 per cent (w/v) molasses, the yield of 0.12 g Mn++/g molasses, the rate ofleaching of 1·06 g Mn++/l/d and a recovery of Mn++ of 58 percent from MnOz were 2·8 times, 1·7 times and 1·9 times greater, respectively. The best compromise in yield (0·45 g Mn++/g molasses) and rate ofdissolution (0·73 gMn++/l/d) was at 1 per cent (w/v) molasses in a stirred reactor.Where leaching organisms were separated from sterile ore by a bacteria impermeable membrane leaching was shown to be some 20 per cent due to diffusible metabolites and 80 per cent due to a direct contact between the bacteria and the ore particle's surfaces.

Jan 1, 1986

Two outstanding features of the world's young orogenic belts are their very consistently developed suites of volcanic rocks and, it is now recognized, the rather distinctive types of mineralization they contain. Further,it is now known that these volcanic suites exhibit evolutionary patterns, and it is beginning to appear that this evolution in style of igneous activity is accompanied by a parallel evolution in style of mineralization. Specifically,podiform chromite and stratiform pyritic copper ores of Alpine ultramafic/submarine tholeiite association progressively give way to more zincian stratiform ores associated with andesites and dacites, "porphyry copper"deposits developed in quartz dioritic to dacitic plugs, and lead-zinc stratiform ores related to increasingly pyroclastic, rbyodacitic volcanism.This "coupling" is exhibited well in the volcanic arcs - the young orogenic zones-of the SW Pacific which, with tbeir abundance of youthful and commonly unmetamorphosed materials provide an opportunity for investigating, through a petrochemical approach, the possible significance of ores in the elucidation of mechanisms of lava formation. It is suggested as a working hypothesis that in the orogenic (voleanic arc) regime ores are associated with the cale-alkaline rocks because these cale-alkaline rocks are in part generated by exhalative loss, and the ores are among the manifestations of tbat loss.

Jan 1, 1978

The Canada Centre for Remote Sensing (CCRS) has developed an airborne sensor, the SWIR Full Spectrum Imager (SFSI) which detects in the short wave infrared range of the solar spectrum from 1220 to 2420 nm. In June of 1995, a demonstration flight was undertaken in the state of Nevada with the support of the companies listed above. The focus of the flight was to collect image data over well known mineral deposits with the objective of evaluating the applicability of this sensor to alteration mineral mapping. Some of the Nevada sites chosen include Cuprite and Goldfield, volcanic hosted acid sulfate systems; Yerington, a structurally complex porphyry copper deposit; and Virginia City, a quartz-sericite-pyrite vein system with advanced argillic pods. Ground spectral data was collected with the PIMA-II spectrometer. Solar reflectance calibration was done by Desert Research Institute personnel at Virginia City and Cuprite. This paper will discuss the configuration of the sensor and present image and ground data for Goldfield and Virginia City.

Jan 1, 1995

In the plumbing of vertical shafts the methods employed and equipment used, are generally made to best suit existing conditions. Undoubtedly, there is no method that can be called standard or that can be used with equal ease and success on all shafts. At the Mount Isa Mines Limited property in Northern Queensland, Australia, local conditions have presented no major difficulties to be overcome in shaft plumbing work. In fact, compared to those at many shafts, the problem has been rather simple. There are three vertical shafts connecting main mine workings, with the greatest plumbing depth for any single lift, 350 ft.Other conditions pertaining to plumbing work have been generally normal.The method we have employed is, in principle, similar to the Weisbach orientation method with a variation that does not necessitate damping of the wires to bring them to rest. Although conditions encountered have not been such that damping the wires would have been inconvenient, we feel we have saved much time and eliminated unnecessary...

Jan 1, 1940

Cook Colliery currently mines in the Argo Seam, beneath old workings in an overlying seam. The Argo seam is up to 4.8 m thick and a continuous haulage system behind an ABM25 is used to develop first workings. Current partial secondary extraction utilises floor stripping and pocketing or sumping first working pillars on retreat. The following paper summarises this recent secondary extraction experience, particularly from a geotechnical perspective, but also considering production and ventilation issues. Outcomes and learnings are presented for mining in this challenging and close multi-seam environment. The sealed castor seam workings are within 20 m, and vary from unmined areas to large first working pillars, to partial extraction panels and full extraction panels. High stress remnant pillars and goaf-edges are notable mining considerations. The mining environment is further complicated by faulting, thrust zones and weak laminated roof.

Nov 25, 2010

By Matthew I. G

A new process for leaching zinc sulphide concentrates with gaseous mixtures of SO2 and O2 in aqueous solution is described.The reaction of SO2/O2 with Rosebery, Mt. Isa, Broken Hill and Elura zinc concentrates yields zinc and iron sulphates, elemental sulphur and some sulphuric acid. Rates of zinc extraction are controlled by a surface chemical reaction without apparent interference from the elemental sulphur layer for SO2 concentrations up to 9 per cent in the gas phase. Pyrite in concentrate exerts an activating effect, possibly through galvanic interaction with the sphalerite. Metal extractions are dependent on SO2 and O2 tenors of the gas, particle size, and the acidity and zinc content of the solution, but are independent of the ferric ion level. Extractions also reach maxima at about 85°C.Generation of acid may be prevented by conducting the reaction in the presence of ferrous iron and at acidities of 40 g/l or greater. Zinc and iron levels in Elura lead concentrate may be reduced by leaching with SO2/O2.

Jan 1, 1981