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CENTRAL mine ore consists mainly of galena and marmatite in a siliceous and rhodonitic gangue, the average assay values being approximately 11.5 oz. per ton Ag, 14.5% Pb, 14.5% Zn, 1.3% Ox Pb, 0.3% Ox Zn.Owing to the 1923 fire in the underground workings, much of the ore now being mined has been subjected to a certain amount of oxidation, as shown by the oxidised values above.This factor is of great importance from a flotation point of view, as a sulphide surface which has been subjected to the influence of oxidation is not as amenable to flotation concentration as a fresh sulphide surface. The importance of this factor is increased when a differential flotation is to be made, and, as in the case of Central mine ore, the sulphide, which is to be floated first, has been oxidised...

Jan 1, 1931

By K Lownie, R Sani, A Sianturi

Part of the PT Freeport Indonesia (PTFI) mine production is in the process of transitioning from the deep ore zone (DOZ) mine to the deep mill level zone (DMLZ) mine. The DMLZ mine is the next lift in the caving series and lies 500 m below the current DOZ footprint.In order to reduce the need for a very expensive additional ventilation system for the DMLZ mine, it was decided to reconfigure some infrastructure and upgrade the performance of the three existing DOZ mixed flow ventilation fans in situ, reducing the new fans required to two. This was far less costly than providing complete new installations.These fans are installed in individual underground chambers in DOZ mine exhaust drifts and connected to the DMLZ mine exhaust drifts system in 7 m × 7 m airways size, through sets of 6 m diameter by 500 m high raises.The upgrade process involved replacement of motors, fan shafts and bearings. The existing 1600 kW DOZ mixed flow fans are 3500 mm diameter and operate at a speed of 595 rev/min and were originally designed to deliver 390 m3/s at 3.3 kPa. Efficiency optimisation may be required at a later date.The upgraded DMLZ fans are required to deliver 425 m3/s at 3.7 kPa and it was necessary to increase in motor size and speed to 2200 kW at 710 rev/min. This paper will discuss the fan upgrade project and in particular the integration of an unusual ventilation system, which is based on the semi parallel operation of multiple large fans.CITATION:Sani, R, Sianturi, A and Lownie, K, 2017. Operation of deep mill level zone mixed flow fans after the first fan upgrade – a parallel fans case study, in Proceedings Australian Mine Vent Conference 2017, pp 285–292 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

A modified liquation technique was developed for recovering tin from tinhouse scruff metal or hardhead containing about 10 per cent iron and 15 per cent occluded flux, palm oil, and moisture. This was effectedby heating the scruff metal to 950°C followed by rapid cooling to suppress the formation of FeSn2 and FeSn, and then subjecting it to the ordinary liquation and drossing processes of refining. By this method it was possible to recover about 83 per cent of the original tin content and, with subsequent smelting of the irony drosses, an overall recovery of 92 per cent was obtained.

Jan 1, 1969

A consideration of mining ventures and the changes of an environmental nature that occur. The paper is introduced with a general statement claiming recognition that mining ventures are important to human well-being but that these need to be justified against the environmental changes that they bring about. The various factors that need to be considered are cited followed by an historical review of mining activities. The various environmental issues are discussed under three headings; socio-economic, physical and biological, prior to reviewing the world's demand for minerals including fossil fuels. In conclusion guidelines for appraising mining ventures relative to environmental changes that may occur, are given.

Jan 1, 1981

By P Illig, R Newberry

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Recent exploration efforts in Eastern Interior, Alaska have discovered significant ca 72 Ma Au-Cu-Ag sulfide-amphibole skarn mineralisation within metamorphic rocks of the Yukon Tanana Terrane, 20 km SE of Tok, Alaska. Contango ORE, Inc’s 1.1 Moz Au-equivalent Peak deposit skarn discovery is hosted by an argillaceous marble layer in quartzite and micaceous quartz schist. This skarn mineralisation is both younger and much more Cu-rich than the typical ca 90 Ma Au intrusive-related gold deposits in the Tintina Gold Belt (eg Ft Knox and Pogo). Silicates at the Peak skarn are predominantly high Cl-, randomly oriented, Fe-rich amphibole, lesser chlorite and minor (<1 per cent) residual clinopyroxene (Hd80–90). Amphibole is ferroedenite to hastingsite and contains up to 4.2 wt per cent Cl-. Pb-Zn-Sb veins are most distal and cut schist wall rocks and amphibole skarn. The predominant sulfide mineral is pyrrhotite, with subordinate arsenopyrite and lesser chalcopyrite, native gold, minor pyrargyrite (Ag3SbS3), trace Jonassonite (AuBi5S4) and maldonite (Au2Bi). Native bismuth, galena, hedlyite (Bi7Te3) and Joseite-A (Bi4TeS2) are also present.Unmineralised garnet (Ad38–43) + pyroxene (Hd60–63) and pyroxene-rich (Hd76–80) skarn occurs in different fault blocks from the Peak skarn and represent proximal skarn related to different intrusive centres. Amphibolites in the region are true metabasites, display metamorphic fabrics and lack the high Fe-Cl compositions of the amphiboles in mineralised skarn. Residual clinopyroxene in the Peak skarn is rare, and most of the hornblende is coarse radial splays that shows no evidence for replacement of pyroxene. Consequently, we propose that the sulfides and hornblende were mostly direct replacements of argillaceous marble and not formed by retrograde alteration of pyroxene-rich skarn. The high-Cl amphiboles indicate that the fluids were Cl-rich and presumably carried Cu via Cl complexing, unlike the Cl-poor fluids associated with ca 90 Ma Cu-poor deposits of the region.CITATION:Illig, P and Newberry, R, 2015. Amphibole Au-Cu skarn and massive sulfide replacement at the Peak deposit, Eastern Interior, Alaska, Peru , in Proceedings PACRIM 2015 Congress, pp 415–422 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By R L. Braithwaite

Mesothermal quartz lodes in Paleozoic Greenland Group metasediments of the Reefton area have produced 67 t of gold up to 1951, and recent exploration has identified new gold resources in several deposits, including the largest past producers, Blackwater and Globe Progress. The metasediments consist of alternating sandstone and argillite, metamorphosed to lower greenschist facies and hydrothermally altered near the quartz lodes. We examined and sampled drill core from four prospects, Globe Progress, General Gordon, Merrijigs and Blackwater, to determine the mineralogical and geochemical characteristics of hydrothermal alteration in the sandstone units. The sandstones are feldspathic litharenites averaging Q65, FlO and R25, with detrital grains of quartz, feldspar, rock fragments, muscovite, biotite (mostly altered to chlorite), and trace quantities of graphite, apatite, zircon, tourmaline and titanite. Hydrothermal alteration has developed a secondary mineral assemblage of K-mica (muscovite, sericite and illite), carbonate, chlorite, pyrite, arsenopyrite and limonite. The abundance of secondary chlorite is greater at Blackwater than at the other locations studied. Features in the sediments associated with increasing hydrothermal alteration towards quartz lodes include, the development and increasing intensity of colour bleaching and carbonate spotting, increasing quantities of disseminated pyrite and arsenopyrite, and the appearance and increasing quantity and size of thin carbonate, quartz and sulphide veins. This is accompanied by increasing concentrations of sulphur, arsenic and antimony as shown in assays, and of volatiles (loss on ignition) and iron as seen in XRF analyses. We were unable to identify consistent trends in the behaviour of potassium, sodium, and calcium that are exhibited by similar mesothermal quartz lode deposits inVictoria, Australia.

Jan 1, 1998

The observation of lower-than-predicted Fe/Cu ratios in the cementation of copper on iron in tests at elevated temperatures indicated that some other reaction was contributing to the reduction of cupric sulphate in addition to the reduction by elemental iron. Experiments showed that the copper sponge, which initially formed on the iron, subsequently reduced the cupric sulphate giving the products cuprous oxide and sulphuric acid.Tests were undertaken to determine the rate and equilibrium conditions of the reduction reaction with variations in the types of the reducing agent and solution parameters. The reaction first became apparent at temperatures above 50°C and as it ceased at pH 1·8 it was possible to induce further reaction by alkali addition.

Jan 1, 1974

By C Ross

This paper uses the results of research trials by Landcare Research and Forest Research Institute and assessments of reclamation plantings at mines and other drastically disturbed sites to describe methods of enhancing restoration of native forests. The characteristics of mine and forest environments are compared to highlight the difficulties facing restoration and techniques which result in successful restoration are described. Selection of the most appropriate technique is illustrated by describing restoration of lowland beech-podocarp forest at a West Coast coal mine. The key to successful reclamation is to understand the factors controlling and limiting plant establishment and growth, then to design rooting media, surfaces and management regimes to create a favourable environment. This paper concludes with a summary of the planning and technical factors which are critical for successful restoration of native forest.

Jan 1, 1995

The Bureau de Recherches Geologiques et Minieres (BRGM) (a French Government-sponsored geological and mining agency), through international experience gained over many years, has become very skilled in alluvial prospection, particularly for diamonds. The research laboratories within the BRGM have also been active in creating new mineral processing equipment, some of which is directly applicable to such prospection. One such development, the mobile prospection unit, is described and its application in mineral exploration is demonstrated by a consideration of the diamond search in Australia and the general exploration of the Massif Armoricain (France). Because this latter study was fundamental in the development of the concept of 'mineral-geochemistry', and its application in mineral exploration, it is also briefly described.

Jan 1, 1971

By Penrose E. K

With the exception of occasional periods, when up to 80% of oxidized ore was treated, the G.M.K. plant treated all sulphide ore until October, 1939. The treatment was, briefly, as follows:The ore was ground to approximately 17% plus 200 mesh Tyler and agitated in cyanide solution, after straking. After agitation, the pulp passed through two stages of counter-current decantation washing in Dorr thickeners and was filtered once, to complete the precyanidation stage.The precyanide filter cake was repulped with flotation circuit solution and floated in a Denver Sub A flotation machine, consisting of twelve cells. The concentrates were roasted, cyanided and filtered four times before disposal to the' dam. The flotation tailings were thickened to conserve water and pumped away to a separate dam.The average results of flotation operations for the six months before October, 1939, are shown in Table 1.

Jan 1, 1942

GOOD ventilation is recognized as an essential for the preservation of health, and laws have accordingly been framed in many countries for the provision of adequate ventilation in factories and places of public resort as well as in mines.Apart from the legislative enforcement of hygienic measures as a matter of public 'policy, the ventilation of mines has an important economic aspect, since it affects to a large extent the industrial efficiency of the workmen, and consequently the cost of mineral production. Until recent years the ventilation of metal mines has not generally received much consideration, and the importance of pure air has been sometimes overlooked. To the absence of explosive gases in such mines, and to the cost of the installation and working of mechanical ventilators, may generally be attributed disregard of adequate ventilation. In this paper it is not proposed to furnish statistics on the mortality and morbidity of miners, or a treatise on the medical aspect of the rock-dust problem, to further elaborate which would be superfluous, the deleterious effects of the latter having been...

Jan 1, 1912

Upon cessation of mining activity open-cast mine pits typically fill with water, forming a æpit-lakeÆ. The water in these lakes, in some instances, contains high concentrations of ædeleteriousÆ material. Containment and/or dilution typically requires an understanding of how stratification in the pit-lake will develop over a long timescale (say 100 years). Vastly different transport rates can develop due to differing hydrogeochemistry, basin morphology and climate. Numerical (computer) modelling is the most likely approach for successful prediction over long times. While lake modelling tools are available, useful numerical modelling requires improved understanding of transport in such systems because they are different to natural lakes in a number of ways. Notwithstanding the effort required to improve our understanding, the modelling provide a means of testing approaches to active management of pit-lakes.

Jan 1, 2002

By W B. Edgar, I M. Platten, C A. J Towsey, B W. Cuffley

The evaluation of historical goldfields has been common over the past 15 years, reflecting changing economic conditions, improvements in knowledge and technology and lack of greenfield sites. Many goldfields comprise narrow gold-quartz veins, which are structurally complex with an irregular distribution of gold, have variable geometry and architecture and display late deformational effects. The study of historical mine records can be an important tool during early and advanced project evaluation, since it contributes to understanding the orebody, exploration target size and setting expectations. Mine records include documents such as plans, sections, reports, news cuttings, production tabulations, etc. A major advantage for the modern explorer is the capability of computer modelling to display this data in 3D. Historical records can give the explorer substantial information on various deposit characteristics, not least grade and geological continuity, geometry and architecture, mineralogy, metallurgical properties, bulk density and ground conditions. From an evaluation perspective, historical records can be used to support a Mineral Resource estimate, though its application will depend upon the quality and quantity of the data and judgement of the Competent Person. Effectively used, historical records can reduce geological uncertainty and focus evaluation efforts û thus reducing project risk.

Jan 1, 2009

By J Kelly, C Kelsey

The Autogenous Kelsey Axial Displacement (KAD) mill is essentially a short retention time centrifugal mill, designed to effectively harness extraordinarily high concentrations of input energy for efficient particle size reduction. The mill which has an operating duty band extending from primary to ultra-fine also has the unique capacity to generate fine and ultra-fine products from single stage size reductions of either coarse or fine mineral feeds, in both wet or dry operating modes. This paper covers developments following a recent optimisation programme which confirmed that mill shell speed and the velocity differential between the shell and the rotating internal disc assembly tips could be optimised in relation to specific energy for a given feed rate and feed size providing the product size remains constant. Subsequent test-work further demonstrated the versatility of the mill with duties ranging from the removal of surface contamination associated with heavy mineral concentrate particles to the production of premium ultra-fine talc, from a single stage of size reduction. Open circuit grinding of a rougher gravity concentrate to liberate gold ahead of leaching also highlighted the scope for the application of low cost KAD milling for a range of hydrometallurgical feed preparation duties, which involve fine and ultra-fine grinding.CITATION:Kelly, J and Kelsey, C, 2013. Advanced media-free fine and ultra-fine grinding - The Kelsey axial displacement mill, in Proceedings MetPlant 2013 , pp 152-161 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

This paper focuses on two sites in the Mount Pleasant - McCormacks Bay area of Christchurch where residential development has taken place either within or immediately adjacent to former quarries for the extraction of volcanic rock. At the Quarry Road site less overburden was dumped on adjoining land around the turn of the century, and c.1980 dwelling and related construction took place on approximately 6 m of relatively loose fill material without the recognition of its presence or geotechnical characteristics. Subsequent settlements led to abandonment of a swimming pool and the underpinning of the 3-storey architect-designed house, whilst litigation brought by the owner resulted in findings of negligence against both the architects and engineers. At the Tramways Quarry site the Council approved subdivision of the former quarry area in the early 1980s without requiring any geotechnical evaluation of batter stability or related issues. During development it became apparent that significant blast damage had occurred to rock faces, necessitating a variety of remedial measures, and that waste materials had been dumped down faces without regard to long-term stability. Both case studies confirm the requirement for careful documentation of former quarry sites by territorial local authorities as part of their administrative function, and for detailed engineering geology and geotechnical evaluation of such areas prior to any residential use of the land.

Jan 1, 1998

Owing to the number of chemical processes now in use for the separation of metals from their ores, and the consequent employment of chemicals at the mine, it is sometimes necessary to be able to produce them on the spot. This particularlyapplies to sulphuric acid which may be required for the manufacture of chlorine and of sulphate of copper, or for the treatment of'sulphides and other purposes. It can be made from brimstone for rather less than £3 per ton, but when delivered to any distance from the works, the cost of packages and other charges would amount to more than the value of the acid.I hope therefore, that to any of the members of the Institute who may find it necessary to make sulphuric acid for their own requirements an outline of the process, and some details of the plant etc may be useful, and perhaps lead to their devising improvements, mechanical or otherwise. Though acid can be made from pyrites in Europe for about 15/- per ton, it is probable that for most metaIIurgical purposes the quantity required. and the uncertainty as to how long it would be needed, would make it advisable to spend as little as possible on plant, and so use brimstone, though more expensive, I have therefore given no details of pyrites burning, which is very fully treated by Prof, Lunge in his work on " Sulphuric Acid and Alkali."

By Johnson N. W

After an unsuccessful transfer from the laboratory to the pilot plant of galena flotation technology which used sodium metabisulphite and ethyl xanthate, laboratory flotation tests were conducted to identify any unusual variables which had a deleterious effect on the position of the lead rougher grade recovery curve for Hilton and Mount Isa silver-lead-zinc ores. Two variables (pulp temperature and contact time for ethyl xanthate and sodium metabisulphite) had important deleterious effects.The findings allowed a successful transfer of the laboratory process to a pilot plant scale process. The effect of temperature was important because the higher temperature (40°C) in the pilot plant pulp increased significantly the rate of reaction between ethyl xanthate and sodium metabisulphite. In the laboratory process at 20 to 25°C, the reaction rate was lower and did not interfere significantly with the process. The contact time for the two reagents was also important in the pilot plant scale process because of the higher reaction rate at 40°C.To employ ethyl xanthate in the pilot plant process, special precautions were required. Further, a collector (Aerofloat 241) from the dithiophosphate family was used successfully in the pilot plant process.

Jan 1, 1988

Recovery of Tantalum Capacitors from Waste Printed Circuit Boards Using a Pneumatic Separator

Sep 13, 2010

This paper highlights the agricultural sector's primary concerns with mining in New Zealand: the information gap, land rehabilitation and compensation. It suggests how these issues can be resolved between the competing land uses in the interests of New Zealand.

Jan 1, 1981

By M Wortley, R Morrison, T Rivett

The tracking of ore through process hold-ups such as stockpiles has been traditionally been difficult to achieve. The inability to pinpoint the exact source in the mine of material that is feeding a processing plant has led to inefficient mine-mill reconciliation processes. In addition, a lack of understanding of the behaviour of ore in process hold-ups such as bins and stockpiles often leads to poor predictions of plant performance and to poor reconciliation of this to the orebody.This paper reports on two short case studies. One case study addresses tracking ore from various parts of two mines to the concentrator. The other follows synthetic particles through the coarse ore stockpile. Both studies use radio-frequency identification (RFID) tracer technology. The paper concludes by discussing general strategies for implementation of such concepts into mine-mill metal accounting and reconciliation systems. As shown in this paper, reliable ore tracking systems will allow much more effective mine-mill reconciliations as well as the ability to model process hold-ups with regard to size by residence time distributions. This should, in turn, allow metallurgists to have a better understanding of the size and grade of material that will report to the plant at different process hold-up (eg stockpile) conditions.

Jan 1, 2009