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By P G. Self, M D. Raven, R A. Eggleton

Investigation of an abandoned quarry near Rowland Flat in South Australia identified asbestiform antigorite as the fibrous serpentine mineral mined during the 1940s to 1978 for filler applications, not amphibole asbestos or chrysotile as reported in earlier investigations. Scanning and transmission electron microscopy (SEM and TEM) and selected area electron diffraction (SAED) of individual fibres were used to confirm the identification. Chrysotile is widely regarded as the only asbestos mineral in the serpentine group. Further work was done therefore, on the geology and mineralogy of the occurrence, and the health implications were reviewed. A zone of antigorite alteration, with associated talc, is traceable for 750 m along strike of recrystallised dolomitic siltstone within Woolshed Flat Shale of Neoproterozoic age. The antigorite formed, in part, by replacement of prismatic crystals of probable tremolitic amphibole. The deposit is proximal to the Williamstown Fault and the serpentine-talc alteration is possibly due to fluids expelled along the fault during late-stage deformation in the Early Palaeozoic Delamerian Orogeny. The antigorite comprises white to pale green bundles of lath-shaped fibres that occur either as randomly- arranged equant patches after amphibole or as cross-fibre veins, both intimately mixed with calcite. Highly fibrous product was mined from the weathered zone where calcite was leached during weathering. Gentle grinding releases fibres with a high aspect ratio (>10:1) that show a wide range of fibre thickness, including a significant proportion of fibres <0.25 ¦m width. Toxicological studies on fibrous antigorite from Poland and Italy indicate that the carcinogenic potential of this form of serpentine is similar to amphibole asbestos. X-ray diffraction (XRD) and fourier-transform infrared (FTIR) techniques readily distinguish antigorite from chrysotile. Determination of asbestiform habit and confirmation of antigorite mineralogy is most reliably done using electron microscopy, preferably with SAED capability.

Jan 1, 2008

By G J. Delemontex, N J. Grigg

Pre-concentration of precious metal and base metal ore types is becoming more relevant with the discovery, development and operation of many lower grade deposits around the world. The fluctuations in metal prices expose many mines to risks especially dealing with low and variable ore grades.Pre-concentration, the process of concentrating the valuable metal into a smaller mass yield, effectively results in the introduction of higher feed grades to milling circuits. Gangue Rejection, the removal of lower S.G. waste rock from the circuit not only results in higher downstream grades but also potentially removes harder, non-valuable mineral, providing significant power savings within the circuit. The pre-concentration or ‘gangue rejection’ process offers a number of benefits when considering the treatment of marginal ore deposits, especially if it can be performed at a coarse crush size; these benefits include a reduction of the operating costs and the feed of more metal units to the mill.Gekko Systems has effectively utilized the Inline Pressure Jig (IPJ) to pre-concentrate the valuable metal, achieving high primary recoveries into a range of mass yields resulting in upgrade ratios between 2 and 10 times.This paper explores the benefits of pre-concentrating ‘marginal’ ore deposits prior to the milling circuit; the selective rejection of ore types that may affect either the recovery or comminution process, and also looks into the potential to effectively reduce the ‘cut-off’ grade when considering the mine planning process. Case studies of projects using the IPJ to pre-concentrate and reject gangue are also included.Pre-concentration and gangue rejection provide the potential to develop marginal ore deposits, thus providing higher grades, less gangue and more metal at a lower operating cost to producers.CITATION:Grigg, N J and Delemontex, G J, 2015. The pre-concentration of precious and base metal deposits using the Inline Pressure Jig – higher feed grades and more metal, in Proceedings MetPlant 2015, pp 296–310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

The development of research activities at Risdon and the implementing of a policy of instrumentation in plant processes have, in recent years, entailed a considerable increase in research staff and created an urgent need for more space and modern laboratory facilities. The existing laboratories have been in use for 25 years and are now inadequate. New buildings have been authorized.The new buildings will comprise, firstly, a laboratory building of three floors giving a totai .floor space of approximately 11,000 sq.ft., and a pilot plant building as an annexe to the laboratory building, of approximately 4,900 sq.ft. The laboratory building will accommodate from 20 to 22 research workers, and additional plant operatives will be used for the control of processes in the pilot plant building. The new buildings are designed to provide facilities for three principal functions; the investigation and improvementof existing processes, the development of new processes up to the pilot plant stage, and the control and maintenance of instruments.LOCALITY AND ORIENTATION OF BUILDINGSThe site of the buildings is elevated ground on the eastern side of the main plant, near the main entrance and general office building. There will be no obstruction to sunshine at any time of the day, and the laboratory building will command views of wide radius from wooded hills across the River Derwentto the open sea on the south-eastern quarter.The buildings are located to provide space for future extensions. The main laboratory building faces approx...

Jan 1, 1949

By Tyler R. J

Methylene blue dye adsorbs on chalcopyrite concentrates slurried in aqueous solution. Saturation adsorption can be achieved within about 24 hours for dye equilibrium concentrations greater than about 10-5 M. The dsorption coverage is obtained from a measurement of the' colour change of the solution. Comparison with BET measurement of the concentrate surface area shows that 2.4 ± 0.1 µmol of methylene blue are adsorbed per square metre of surface accessible to the dye cation. The procedure described can be used as a single-point measurement and values for the surface area can be otained to within about 10 per cent with inexpensive instrumentation.

Jan 1, 1979

By Gordon DM

Tyres account for 25-30 per cent of the operating costs of large capacity haul units as used in open-cut mines.Tyre operating costs can be substantially reduced and often contained in real terms by applying knowledge that is now available.This paper describes certain specific advances in tyre management, namely batching, bias adjustment, cumulative plotting and the so-called "pressure-temperature" system of tyre pressure control, originated on the Mt Newman Mining Company's Newman minesite, and discusses the contribution that each has made to improving tyre management and reducing costs.

Jan 1, 1983

By M P. Simpson, J L. Mauk

The Golden Cross, low-sulfidation, epithermal deposit shows a number of features that are directly or indirectly related to boiling hydrothermal fluids. Occurrences of lattice calcite and their quartz pseudomorph equivalents in veins, and occurrences of adularia in veins and in the surrounding altered rocks in the vicinity of ore, are both direct evidence of deposition in the presence of boiling hydrothermal fluids. Loss of carbon dioxide causes calcite deposition (platy variety) near the level of first boiling, while adularia deposits due to the attendant pH increase along the cooling flow path. Indirect evidence of boiling include crustiform-colloform quartz banding, late massive calcite veins, clay-carbonate alteration in the shallow and peripheral parts of the ore zone, and the restricted vertical interval of precious metal mineralisation. The colloform quartz banding strongly resembles the banding in amorphous silica deposits found in geothermal surface pipes. This implies that fluids ascending the Empire Vein structure were saturated in amorphous silica. If so, then they must have undergone phase separation, which initiated at considerable depth (e.g. =1000 m) and very hot temperatures (e.g. =300¦C). On the basis of stable isotope data, late massive calcite veins appear to have deposited from CO2-rich steam-heated waters. Calcite deposited along heating paths as these waters descended into the upflow zone during late stage collapse of the hydrothermal plume. In active systems, such steam heated waters form by deep boiling. The high CO2 contents of these waters promote hydrolytic alteration and the formation of clay-carbonate alteration. Reaction path modelling using CHILLER and a deep, Broadlands-Ohaaki water as an analogue, shows that minerals deposit along boiling flow paths over discrete spatial intervals. Calcite and adularia deposit near the site of first boiling, followed by gold and then by amorphous silica. For deep boiling starting at 300¦C, these minerals deposit over a path length that exceeds 1000 m. The distribution of banded quartz and gold at Golden Cross are consistent with such a boiling model. However, the elevation of first boiling must have fluctuated over 500 m to account for the coincidence of lattice quartz (pseudomorphs of platy calcite) and adularia, crustiform-colloform silica and gold over distances of a few centimeters in veins. We deduce that a downward propagating boiling front and expansion of two-phase flashing in a flowing water column occurred during episodes of high vertical permeability and fluid flux in the Empire vein structure.

Jan 1, 2000

By K Gordon, A Black

Two remediation strategies have been considered to reduce the levels of acidity and dissolved metals in acid mine drainage discharging from Sullivan Mine, West Coast, New Zealand. The oxidising strategy involves adding alkalinity and dissolved oxygen (DO) resulting in the precipitation of metallic oxides and decreased acidity. The reducing strategy involves removing DO, resulting in the precipitation of metallic sulfides, followed by addition of alkalinity to decrease acidity. Field remediation trials indicate a reducing system may be more effective for this site than an oxidising system. A residence time of only two hours in the limestone layer of a successive alkalinity producing system (SAPS) is sufficient to reduce acidity by 100 per cent, iron by 71 per cent, aluminium by 59 per cent, nickel by 38 per cent and manganese by 26 per cent. The proposed remediation plan will likely include a series of SAPS, followed by an anoxic limestone drain, and settling ponds to capture any remaining precipitates.

Jan 1, 2003

A brief review is given of the history of the Colliery to date together with the reasons for the development of an additional seam.Investigations into the quality of the coal ami its suitability for the production of metallurgical coke and determination of the economic mining limits and coal reserves are discussed. The commencement of mining operations and the inter-seamarrangements necessary for the disposal of coal won are described with the stages in the opening out of the seam itself and the reasons for the installation of a 48-in. trunk conveyor belt. Choke and manning of face equipment are considered and also the work of secondary development and pillar extraction.It is concluded that with modern face equipment and conveyor belt lines, concentrated mining followed by immediate extraction of pillars is practicable and is giving excellent results at Burwood Colliery.INTRODUCTIONBurwood Colliery, the total holding of which now comprises some 3,140 acres of land and 1,450 acres of sea leases, has mined the Borehole Seam since 1883. The early work took place from Nos. 1 and 2 shafts at Glenrock Lagoon and later on at Nos. 3 and 4 shafts at Whitebridge to which the centre of operations shifted in 1893, shaft sinking at this latter area having commenced in 1888.As all the early operations were confined to the Borehole Seam, reserves of coal on this horizon had been considerably reduced by the mid 1930's, so a cross measure drift was driven to the Victoria Tunnel Seam which is about 300 ft. above the Borehole Seam, and fully mechanized coal winning commenced from the second seam in 1938. Subsequently this cross measure drift was extended to the Borehole Seam and complete mechanization of the south-west sections of this seam achieved by 1945.Four track mounted mechanical units were put into operation in the latter area and these worked in a southerly and...

Jan 1, 1958

By G Small, A Lazamanana, C Greet

When conducting gold leach tests on free milling gold ores which method is the best, bottle rolls or the stirred beaker test? Recently, a client requested that gold leach tests be conducted using the stirred beaker methodology. When asked why, because the laboratory was set up to conduct tests using the bottle rolls technique the reply was that the stirred beaker leach test would replicate the plant more closely. Not wishing to upset the client, the instructions were followed. However, the opportunity was taken to complete additional tests so that the two leach procedures could be compared. Further, this comparison was completed on two different gold ores as well as a number of different grinding media types.This paper provides a description of the two laboratory techniques employed, and presents the results of these parallel tests. Interestingly, the assertion that the stirred beaker methodology more closely replicated plant performance was not validated. In fact, the results obtained using this procedure were noticeably different from those observed in the plant, with lower recoveries and significantly higher cyanide consumptions. The bottle rolls test however more adequately replicated plant performance in terms of recovery and cyanide consumption. The reasons for this are discussed in the paper.CITATION:Greet, C, Lazamanana, A and Small, G, 2015. Bottle rolls versus stirred beaker leach testing – which is best?, in Proceedings MetPlant 2015, pp 188–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Wylie A. W, Mathew P. J, Eisler P. L

Field studies of the radiations backscattered by iron ores from a 60Co source of primary gamma radiation located in a borehole logging probe have confirmed thatthe P" factor, a ratio of high energy gamma ray intensities to low energy intensities in selected energy windows of the backscattered gamma-ray spectrum, is a valuable measure of grade for sedimentary iron ores of the Pilbararegion of Western Australia.Laboratory studies of model boreholes have shown that variations in borehole diameter and variations in bulk density of the formations have a significant influence on the measurement of P" ratios. If these influences 'are taken into account the mean ore grade in a new blast hole, for instance, can be predicted with a probe of suitable configuration to within 0·8 per cent Fe at the 95 per cent confidence level, while the grade of a single 120-cm split can be determined to within 2·6 per cent Fe. These results were obtained by pooling data from five blast holes covering the range of iron concentrations 20-68 per cent Fe and apply to the mean hole grades 54-68 per cent Fe.Results for two development holes were generally comparable to those obtained from individual blast holes95 per cent confidence limits of ±0·9 per cent Fe for mean ore grade and ± 4·1 per cent Fe for single splits. A greater number of data points is needed before these confidence limits can be further improved.The technique utilized to obtain these results was derived from a "multiband" approach to collection of backscattered spectral intensity data, an approach which permitted selection at the data processing stage of the most statistically significant P" ratios for the type of mineralization encountered in the field. The multiband technique also permitted selection of the most significant of another set of windows in the backscattered gammarayspectrum to measure a newly developed "S-factor", a ratio sensitive to borehole diameter. Another window provided information on bulk density. All these measurements were made with a single pass of the same loggingprobe.

Jan 1, 1977

YOUR Excellency, Fellow Members of the Australasian Institute of Mining Engineers and Gentlemen:-Nearly a decade has passed since our Institute first met in New Zealand. May I, at the very outset of this second gathering, congratulate the Institute on the great progress that has been made in the interval. At the first meeting in New Zealand in the year 1903, I understand that less than 20 persons were present, and now in the large concourse before me I believe there are not fewer than 140 persons, while if every member of the Institute to-day where here there would be over 500 with usagreat change from a membership of only 250 in 1903. I feel deeply appreciative of the honour you have conferred upon me by electing me your President for the year 1911. In return for the compliment, may I ask you to believe that I shall do everythingin my power to further the interests of the Institute throughout the coming year.It is a great regret to me to realise that soon my work in New Zealand will be over. However, I trust that the new...

Jan 1, 1912

By A M. Hagni

Certain copper ores from the Nchanga Copper Mine in the northern Zambia Copperbelt are refractory with respect to conventional beneficiation techniques. This paper reviews recent study of those ores to determine their mineralogy, textures and nature of copper occurrence. Two suites of refractory ores were selected for study: 1.  samples of stockpiled ores from an open pit, and 2.  drill core samples from copper ores. Both sample suites are from the upper orebody at Nchanga and contain about 0.3 - 1.4 per cent copper as determined by atomic absorption, but they represent separate stratigraphic, mineralogical and beneficiation problems. Ore microscopic examination showed that fine-grained copper sulfides are totally lacking from both suites of refractory ores. Petrographic study found malachite in the refractory ores from the open pit, but that malachite probably is post-mine. The opaque mineralogy of the open pit refractory ores is dominated by goethite that occurs mostly as pseudomorphic grains after pyritohedral pyrite crystals that average 200 - 250 ¦m across. Haematite occurs as bands within or as outer shells of the goethite grains. Additional goethite occurs locally as finer-grained areas of exotic goethite. The opaque minerals in the drill core refractory ores are dominated by euhedral ilmenite crystals about 50 - 175 ¦m long. Anatase is the dominant opaque mineral in some drill core samples where it is largely pseudomorphic after ilmenite crystals. Goethite accompanies malachite in unusual drill core refractory ores that have experienced intense hydrothermal alteration. Thus, ore microscopy and petrography showed that fine-grained chalcopyrite and bornite and pre-mine malachite were not the causes of the refractory nature of the ores studied. Electron microprobe revealed that most of the copper occurred in solid solution within micas. Application of automated SEM techniques has provided a detailed understanding of the distribution of copper in these refractory ores.

Jan 1, 2008

The mineral industry is an important element in the human environment and in varying degrees contributes to the general standard of living throughout most of the world, both by supplying the basic materials required for heavy industry, transportation, construction, scientific equipment, and many labour saving tools and also by its contribution to the international economy.When projecting population growth and per capita resource utilization against a finite amount of nonrenewable mineral resources, it is apparent that at some future time, if the established trend continues, the supply of industrial minerals will progressively become exhausted according to their relative scarcity and world demand.In one way or another all of nature's mineral resources are used in the sel'vice of man. Some of the products of their manufacture are essential to the survival and further development of our civilization, others are luxuries, desirable but not essential. Marine vessels are essential to maintain a flow of resollrces around the world, and as trade increases the size of the fleet will grow and the quantities of metals needed will be greater.The commodities they transport, may be used in an inefficient or extravagant manner causing unnecessary depletion which may adversely affect the activities of future generations. An example that comes readily to mind is fuel oil, the international transport of which uses a vast tanker fleet. When refined, large quantities of motor spirit are used in motor vehicles. The U.S.A. alone uses 70 billion gallons annually in the 90,000,000 automobiles in use.Much of this is used in private cars-of which there is one for every 2'3 people-for transport between home and city. Well organized community transport would serve the same purpose, conserve a scarce commodity, take some of the stress out of livingdriving in a major city can hardly be considered a relaxing experience-and minimize the problem of atmospheric pollution.Whilst man has demonstrated his great versatility...

Jan 1, 1973

FOR rapidly marking in geological and topographical features on parish plans, the author has used the Veeder cyclometer with very satisfactory results. A simple Veeder cyclometer, usually retailed at cycle depots at 4s., is fixed to the axle of the front wheel of an ordinary bicycle. The cyclometer is desigued to read in miles and tenths of miles, which are recorded through gearing actuated by a striker on a spoke of the bicycle wheel engaging one of the vanes of the cyclometer once every revolution.By using 80 strikers the reading would be in chains and tenths of chains; therefore the use of 8 strikers gives the reading in chains, utilizing all the figures. The cyclometer is designed to be placed on the right-hand side of the bicycle, and takes up a minimum of space, being only about the size of the top joint of the thumb. With some makes of cycles there is insufficient clearance, so the cyclometer must then be placed on the left side, and the 8 strikers made to engage the top vanes, as shown in the sketch (Fig. 1).Very accurate readings can be obtained by this instrument. The author has found by numerous tests that the maximum error...

Jan 1, 1916

The rapid advance in the adaptation of scientific knowledge to the treatment of ores, resulting in improved chemical and metallurgical processes, has enormously increased the possibility of working lodes profitably, which a few years ago were passed over as unpayable. By the discovery of chlorination, and later of "Cyanidation," by the highly improved methods of concentration, and by the rapid advance in our knowledge of smelting (for which we are greatly indebted to Americanmetallurgists), and by the gradual replacement of scientifing principles and enlightened management, for rule-of-thumb methods formerly in vogue, many large low grade bodies have been opened, and are now paying dividends, which were,twenty years ago, looked upon as hopelessly unpayable. It has been more especially in these large low grade ore bodies, that modern methods have been benefical; for small lodes must be rich to pay at all, as they cannot be worked on the same gigantic scale, but even in these a percentage of metal is saved which formerly was absolutely lost.To make these large deposits remunerative it is, however necessary to try and find the point of greatest economic advantage, to handle the ore in vast quantities, to erect huge plats to treat it, to substitute automatic appliances for hand labour as far as possible, and to combine several processes supplementary to one another, so that ore which is not amenable to one process, shall be saved, by another; and by doing...

Jan 1, 1901

The Illawarra District, from 50 to 100 miles south of Sydney, is one of the State's important coalfields. It extends from Clifton on the north, to the Shoalhaven river on the south, and from the coast westward beyond the coastal scarp.For descriptive purposes, this area falls naturally into two zones:(a) the coastal belt backed-by the eastern edge of the plateau;(b) the plateau, westerly from the coastal scarp.(a) The Coastal Belt.A triangular shaped area extending from Clifton to the Shoalhaven river, composed for the most part of soft coal measures strata of Permian age, which, on weathering, undermines the massive overlying Mesozoic sandstones and causes the gradual recession of thecliffs.South of Wollongong, upper marine sediments and contemporaneous igneous rocks make their appearance beneath the coal measure beds and occupy the greater portion of the coastal belt.(b) Plateau Area.Extending westerly from the coastal escarpment is a plateau known as the Robertson Tableland, composed of Triassic sandstone and shales dipping gently in a northerly direction, and capped in places by Wianamatta. shales and r.rertiary basalts. This tableland is approximately 2400 feet above sea level in the vicinity of Robertson, and gradually falls to about 750 feet at Waterfall.The plateau area for the most part is highly dissected, rough, steep gorges alternate with sharp ridges.A large part of the northern watershed of the Robertson tableland is a reserve for Sydney water supply, and large dams have been constructed at Cataract, Avon, Burke, and Cordeaux.

Jan 1, 1938

The objectives of this paper are two-fold. First, it will show what problems can arise when single estimated values are substituted for a distribution of values when evaluating an open pit mine project in the face of uncertainty. Secondly, it will show how the ability to deal with uncertainty and risk in mine project evaluation can have a significant impact on the ownersÆ and stakeholdersÆ investment decision-making. Here a new mine evaluation framework, the integrated valuation/ optimisation framework (named IVOF), is introduced as an alternative tool for mine project evaluation where uncertainty and risk are incorporated in the evaluation process.

Jan 1, 2009

By A Goldstone, T Maton

The Golden Cross Mine is located on the North Island of New Zealand, at the base of the Coromandel Peninsula, approximately 8 km northwest of Waihi. The project is operated as a Joint Venture with Coeur Gold New Zealand holding 800/0 and Viking Mining Limited with a 20% interest. The past open-pit and underground gold and silver producer has been in the reclamation phase of the operation for approximately 2.5 years and is now nearing completion. Although rehabilitation of the site is a regulatory requirement, the Closure Plan has been enhanced by the ongoing commitment of the Joint Venture to establish a sustainable land use for the site by commissioning engineered facilities designed to last for perpetuity. The Joint Venture identified six significant design features that were key to successful rehabilitation. These were the controlled placement of acid generating waste rock into engineered disposal sites; the design and placement of sealing layers over the waste rock disposal sites; the design and construction of diversion drains; the establishment and management of vegetation to protect the oxygen diffusion layer; a partial capping of the tailings to accelerate consolidation adjacent to the tailings dam embankment, and the implementation of a cyanide recovery circuit to recycle cyanide from the tailings prior to disposal. Another key to success for the project involved genuine consultation with all parties participating in the planning, evaluation, and consenting of the closure process at Golden Cross. The local and regulatory community has been widely represented in the Joint Venture's operating and closure plans throughout the history of the mine. Participants include: Regional and District Councillors and staff members, professional peer reviewers, environmental groups, local residents of the valley, and Iwi. This overall commitment to the project has resulted in a world-class rehabilitation program for the first modern metal-mine closure in New Zealand and we believe that collectively, the work done at Golden Cross is helping to set a standard for the success of future programs within the extractive industry.

Jan 1, 2000

By Ralph B. S

Bacterial leaching of low grade quartz felspar porphyry copper ore was studied in large-scale laboratory percolation leaching columns.Limitations in the release of soluble copper showed up before fifty per cent recovery, due to occluding precipitates of iron oxides and hydroxides. Precipitates were removed by increasing the acidity of irrigation feed four-fold with respect to sulphuric acid. However, irrigation at low pH (pH 1.5) inhibited copper leaching. Resumption of bacterial leaching at pH2 was achieved by introducing a period of non-irrigation. The results suggest a 'direct' attack by bacteria on the chalcopyrite substrate rather than an 'indirect' ferric-leach mechanism.

Jan 1, 1981

E. W. Stutchbury (Internationa~ Oombustion Aust. Ltd.) : Mr. Callcott made particular mention in his paper of erosion in primary air fans which are placed after the mill discharge. He adds that subsequent reduction in plant performance and resulting increased maintenance costs occur. It is generally assumed that this statement is substantially correct as the fan handles the complete output from the mill, but with modern materials, reduction in performance and subsequent .maintenance are not now a problem. This consideration of handling the pulverised coal in the fan is more than offset by the advantage of operating the mill under suction which results in cleaner operating conditions, simpler feeder arrangements and elimination of complicated seals on the mill.and feeder unit. It should be specially noted that whereas mill exhausters in the past have used chequer plate blades (sometimes with the addition of hard facing by electrode deposit) it is modern practice to provide fan blades of up to 1 in·. thick Ni-hard suitablyheat treated, with the circumferential section of the fan also in Ni-hard. By the use of this material large power...

Jan 1, 1957