Search Documents

By Ryan A, Dennis R, Dekker D, Ellis W, Sowerby B

An automated facility for non-destructive elemental analysis of mine samples has been developed and tested at Mount Isa in association with the CSIRO. The analysis is based on the prompt and delayed measurement of gamma radiation emitted by the sample during and after separate fast and thermal neutron irradiation. No sub-sampling or sample preparation is required and the analyser is operated by one person that would otherwise be splitting drill core in preparation for conventional analysis. The analyser has been calibrated to measure the following (precision in parenthesis): Ag (14 ppm), Pb (0.5 wt%), Zn (0.5 wt%), Cu (0.04 wt%), Fe (0.7 wt%), S (1.1 wt%), SiO2 (0.8 wt%), A1203 (0.07 wt%), Mn (0.05 wt%), specific gravity (0.02 g cmt). Crushed or whole drill core samples that range in size between 0.5 m and 1.8 m of equivalent BQ size drill core can be analysed at a rate of six samples per hour. If required, drill core samples can be re-packed in their original configuration for storage following analysis. Standard samples are measured every day to ensure operational stability. The analyser is controlled by a personal computer which prints the results and stores them along with the raw data on the computer hard disk. This paper reports the performance of the analyser during 1992 for routine analysis of drill core from the lead ore bodies of both Mount Isa and Hilton mines.

Jan 1, 1993

Since 1969, a substantial number of geophysical methods have been applied in the search for porphyry copper and mesothermal type -sulpha-de deposits. These have assisted with geological mapping as well as the definition of various sulphide depos-its. The application of these methods at the Frieda-Nena deposits, Papua New Guinea, can be used as a case study for exploration in other parts of New Guinea.In 1993, Highlands Gold Limited carried out an intensive geophysical program over the Nena deposit. The methods employed included, CSAMT (controlled-source audio magneto-tellurics), airborne and ground elect-romagnetics, IP/resistivity and ground magnetics. The magnetic method was used as a regional mapping tool as well as a way of mapping alteration zones over both the Nena and Frieda River copper deposits. Electromagnetics, in part-icular FLAIRTEM, is a rapid reconn-aissance tool as well as a detailed mapping tool for the location of Nena-style massive sulphide deposits. IP/ resistivity is an expensive but most useful tool for mapping out Frieda porphyry copper style disseminated sulphides as well as Nena style deposits. It can be used to define drill targets in areas of difficult Access.a

Jan 1, 1994

By Marshall K. I

THE problem of satisfactorily eliminating the fumes and dust which are unavoidably produced in various metallurgical and manufacturing industries is one which has received considerable attention in the past, and has been the subject of much investigation and research. The solution of this problem was urgently desired for two reasons, the principal one being the fact that a considerable percentage of the total process losses in many industries was represented by the commercial values of the fumes and dust that escaped from the stack.The other reason is that, in some instances, the emission of the matter is regarded as objectionable. Various methods have been designed with a view to solving the problem thus presented, and the latest development that has beendesigned is the process of electrostatic precipitation. Continued investigational and developmental work with this process has already demonstrated its applicability to many industries, and new uses to which the process can be put are being opened up. Its use is already widespread, and the economic success that has attended its application in most instances would indicate that its use will become more general in the future.It has proved its ability to treat gases over wide ranges of temperature, and has successfully handled various types of fumes whose chemical characteristics differ very considerably. In many processes it has now come to be regarded as standard equipment.HISTORY OF ELECTRICAL PRECIPITATIONThe first recorded observations on the influence of an electrified insulated wire on gases containing solid particles in suspension was made as early as 1824 by Hohlfeld, in Leipzig. He found that, if he electrified a wire hung in a bottle filled with smoke, the smoke cleared rapidly, and a deposit formed on the sides and bottom of the bottle.

Jan 1, 1923

By Smith I. W

Australia has, and faces, a growing problem with regard to the ability to meet the demand for liquid fuels from indigenous petroleum resources. The position for natural gas is better but there is no room for complacency. Since the coal resources are relatively extensive, interest in the prospect of producing liquid fuels from coal is in- creasing. The approaches to the production of gaseous and liquid fuels are briefly reviewed and the present status of coal conversion technology is discussed. Many problems remain to be solved and it is estimated (in the USA) that another 8-10 years will be required before any of the processes for liquid fuel production are considered sufficiently efficient and viable to go to a demonstration plant. Coals represent complex feedstocks and the effects of variations in coal properties on oil-from-coal processes are not fully understood. The thermal efficiencies of various coal conversion processes are considered in relation to their impact on coal requirements. The production of Australia's present requirement for liquid fuels by the only commercial process in operation would require a four-fold expansion in the local consumption of coal. Any assessment of the suitability of oil-from-coal processes currently under development overseas for Austra- lian coals and requirements must take heed of the differences in coal properties and motivation. The economic via- bility of processes for producing oil from coal will continue to be uncertain because of the large difference between the World price for crude oil and the actual production cost.

Jan 1, 1975

Universal Resources Ltd has acquired a large portfolio of high quality exploration projects in two of Australia's most prospective regions for base and precious metal exploration: the Mt Isa Inlier (the Mt Isa-Cloncurry area) of North West Queensland, and the southern Lachlan Fold Belt in New South Wales. Drilling techniques commonly employed by the company for mineral exploration include diamond core drilling, air core drilling, reverse circulation (RC) drilling, and rotary air blast (RAB) drilling. Using examples from these two regions, each drilling technique is briefly described and compared, with particular reference to the specific advantages and disadvantages of each method for: sampling size, sample representivity, recovery, integrity and potential contamination. The applicability and implications of the different drilling techniques described for subsequent mineralogical and metallurgical evaluation work are discussed.

Mar 1, 2010

By G J. Keyter, P J. Terbrugge, Yu Xianb

There has been disappointingly little development in the understanding of the behaviour of rock slopes in open pit mines over the past 30 years. The lack of development in general, and of robust, standardised approaches in particular, are surprising in view of the æultraÆ deep open pit mines that are being developed to depths in excess of 1000 m. Research has recently been carried out into the occurrence of zones of extension strain in open pit slopes. This showed that very large zones of extension strain can occur, and this finding represents a significant new aspect in slope stability that has not been considered before. The greatest magnitudes of extension strain occur near the toe of the slope, either in the slope itself, or in the floor of the pit. Results of the research will be presented for different slope heights, slope angles and horizontal to vertical in situ stress ratios. The magnitudes of the strains are considered to be large enough to result in fracturing of intact rock, and the fracture orientations predicted are adverse for slope stability. Fracturing that is extension in nature is common in competent, brittle rocks and often develops with some violence and little or no warning, producing easily measurable seismicity. In the slope situation, the expected physical manifestation of this behaviour would be popping off of rock slabs and plates of rock from slope surfaces and popping up of the pit floor, as well as the formation of new fractures within the rock mass. Such behaviour may cause overall slope failure, or may initiate failure, which may then be driven to overall slope failure by other influencing factors or combinations of factors. In addition to instability resulting from the fracture surfaces themselves, all induced fracture surfaces could interact with natural geological structures to facilitate formation of a significant failure surface. Case studies of slope failure in two open pits will be described. In both cases failure occurred æsuddenlyÆ after very limited amounts of deformation. In the first, the slope crest moved suddenly upwards and backwards over a length of more than 200 m, with associated instability. In the second, the horizontal displacement of the slope face was almost an order of magnitude greater than the vertical displacement and occurred æsuddenlyÆ. A recently installed seismic system is detecting events in a significant zone behind the slope face. Both pits were in the 200 m to 300 m depth range at the time of the occurrences.

Jan 1, 2003

By Corbett GJ, Leach TM

The Nena Cu-Au high sulphidation deposit has formed within the Frieda River Intrusive Complex in association with a major dilatant structure. Multiple intermediate intrusives of Miocene age are localised by a splay (Frieda Fault) of the Fiak-Leonard-Schultz Thrust, a several hundred kilometre long structure, formed parallel to the accretionary prism of northern Papua New Guinea.The high sulphidation systems including Nena, crop out as narrow silica-alunite ridges extending for up to 5-6km in length within a dilational structural environment. Alteration at Mena exhibits two phases of hydro-thermal activity: an initial stage, inferred to be volatile-rich, which has produced zoned alteration; and a later phase, postulated to have been a liquid-dominated fluid, which has brecciated earlier alteration zones and deposited gangue phases as well as Cu/Au-bearinq sulphides in open spaces.

Jan 1, 1994

By Kobe HW, Balance PF, Black PM, Sporli KB, Smith IEM, Locke CA

The Hauraki Goldfield consists of a large number of volcanic-associated epithermal gold deposits within the Coromandel Volcanic Zone (CVZ), North Island , New Zealand; it is the most accessible and most studied of the Southwest Pacific gold regions. The deposits occur generally as steeply dipping quartz veins and breccia sheets in faults and fractures.From a tectonic perspective, the CVZ is generally considered a Neogene convergent volcanic arc constructed under an extensional tectonic regime; the common tectonic setting for epithermal mineralisation. The gold deposits are mostly hosted in subaerial andesitic arc-type volcanic rocks. Temporally, however, mineralisation is associated with rhyolitic rocks of a bimodal volcanic suite that may represent a back-arc environment. Rifting and calderas may be important components of the latter regime, but this is not yet clear; the general structural framework controlling the location of CVZ gold deposits remains poorly understood. Geophysics, particularly aeromagnetics, has a role in mapping regional fault patterns in the CVZ

Jan 1, 1990

By Espi J

The Nena high sulphidation deposit, located in the Sandaun Province, PNG, contains a measured and indicated resource of 51 Mt of copper ore grading 0.5% Cu and 0.6 g/t Au at a 0.5% Cu cut-off. The copper orebody is overlain by an 18Mt oxide gold resource grading 0.1 % Cu and 1.4 g/t Au at a 0.6 g/t Au cut-off. The deposit is hosted in advanced argillic altered pyroclastics interstratified with lavas, volcanoclastics, epiclastics and sediments of the Debom Volcanics within the Frieda River Intrusive Complex. Foraminiferal sediments indicate the Debom Volcanics to be Early-Middle Miocene in age. Alteration is elongated along, and concentric about a northwest trending structure (Nena Structural Corridor) which is about 7km in length. The inner two alteration types, residual and massive silica-alunite are strongly brecciated and host the bulk of later hypogene Cu-Au mineralisation. Weakly mineralised weak silica- alunite and barren peripherally zoned clay alteration surround the inner mineralised alterations. The hypogene sulphide deposition was polyphasal, episodic and is zoned from north to south from covellite-enargite ¦ chalcocite (5600N to 5200N) to a mixed enargite-luzonite (5200N to 4700N) to luzonite-stibioluzonite (4700N to 4400N) in the south within a 1200m long by 300m diameter sub horizontal pipe like body. Paragenesis studies indicate that pyrite ¦ marcasite were introduced early with barite and black native sulphur before deposition of banded pyrite (melnicovite) with barite during a period of brecciation. Continued brecciation allowed bladed covellite ¦ chalcocite followed by enargite-luzonite-stibioluzonite ¦ pyrite (brassy) and minor acicular covellite deposition. Yellow native sulphur and trace amounts of galena were deposited in remaining pores. Pre-acid alteration intrusives domed the mainly volcanic stratigraphy in the southwest and post-mineralisation porphyries in the northeast truncate mineralisation. Supergene processes and erosion have modified the top of the deposit, creating a 45m thick goethitic-scoroditic-haematitic gold cap above a 40m thick (on average) chalcocite rich supergene blanket. Lesser amounts of digenite, covellite native copper and rarely seen malachite occur in the supergene copper zone.

Jan 1, 1997

Many volcanoes in western Melanesia have tectonic settings and rock compositions that do not conform to conventional models of arc- trench systems. Part of the reason for this may be that in an environment of rapid tectonic change mantle source regions bear the imprint of former subduction even though subduction has now ceased. Results bearing on this concept and on other important aspects of Plelit nesian v ican ism and tectonics, were obtained in 1982-1986 from >e,:eral marine - geoscience studies in the re,,ii n

Jan 1, 1987

By Quast K. B

Samples of limestone and micaceous hematite have been ground in a laboratory batch mill using equal weights of either rods or balls. Values of the Schuhmann distribution modulus, a, have been shown to depend on grind time and do not remain constant as often reported. The linear reduction in a with grind time was attributed to a change in grinding mechanisms with time. The product sizing from ball milling limestone showed a bimodal distribution, but rod milling produced a unimodal size distribution. The product sizing from milling micaceous hematite was difficult to interpret due to the major influence of the shape factor on the transition from screen sizing to cyclosizing.

Jan 1, 1995

By Collins M. J, Ozberk E

A major advantage of the Sherritt Zinc Pressure Leach Process is the conversion of sulphide sulphur in zinc concentrate to elemental sulphur during pressure leaching. Elemental sulphur can be recovered as a marketable byproduct by flotation of the leach residue, and melting and filtration of the sulphur flotation concentrate. The behaviour and deportment of sulphur during pressure leaching, flotation, and melting and filtration are discussed in this paper using data obtained from the treatment of a wide variety of zinc concentrates in the laboratory miniplant at the Sherritt Research Centre. The quality of the elemental sulphur byproduct and a process for purifying the sulphur are also Presented.

Jan 1, 1993

The theme of my address to your Institute, indeed its name, is "The Mineral Industry - What Next?" Knowing that I was required to make four appearances, and not wanting to be too repetitious, I wrote a rather long speech of which I will deliver various sections at different places, with a common introduction. Specific areas I have addressed are "Exploration", "New sources of minerals and energy", and "Mining and metallurgy of the future".

Jan 1, 1984

By M B. Lovitt

At present there exist few engineering calculations and principles to determine exclusion zones for personnel in the vicinity of underground explosive storage areas. This paper is written to encourage discussion and proposes a method to determine the impact of a blast wave through scientific principles. Then, criteria to determine an ‘exclusion zone’ need to be identified.There has been much work on identifying the pressure rise and the energy of explosive detonations underground but little to develop standards in criteria that can be used to identify exclusion zones for useful design of underground infrastructure. The author presents the newest ways of calculating the pressure rise and energy (impulse) of detonations and puts forward some criteria to be used in the identification of personnel exclusion zones to spark peer review and discussion of these criteria towards developing standards for engineering design.Smith and Sapko (2005) used Sach’s scaling laws to develop a relationship for both pressure rise and impulse, which incorporated factors for intersections. Intersections will have a large bearing on the peak pressure and the energy of the blast wave and needs to be incorporated. Silvestrini, Genova and Leon Trujillo (2009) developed the scaling laws with an energy concentration factor to predict blast propagation in partially confined geometries and together the author has proposed equations for determining the peak side pressure and the impulse in a tunnel. Given the weight and type of the explosive, the average cross-section of the tunnel complex and the number and type of intersections encountered, the pressure and impulse can be calculated.The military has carried out many investigations as to the influence of blast pressure and impulse on the human body. Lung damage, ear damage and velocity knock down are three of the criteria standards that are presented as possible methods of determining exclusion zones around an underground explosives magazine. The author suggests that the velocity curves presented by Bowen, Fletcher and Richmond (1968) could be an acceptable method of determining an exclusion zone as it incorporates the side pressure and the energy of a blast wave to determine the ability of the wave to knock down personnel.CITATION:Lovitt, M B, 2014. Exclusion zone calculation for underground explosives storage, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 319–326 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

Tumbling mills have been used in the minerals indusu) for occr WO years, with the design changing little, but the size of the individual pieces of equipment increasing significantly with the lowering of head grades, and the push for greater

Jan 1, 1997

The Barra Mine was the most significant mine of Australia's earliest mining era, which took place in South Australia between 1841 and 1851, the decade prior to discovery of gold in eastern Australia. Between 1845 and 1860, Barra was the largest metalliferous mine in Australia and employed up to 1000 men and boys, most of them Cornish.""Today the site is also important in a physical and archaeological sense as it contains extensive remains of mining and processing operations of the period 1850 - 70. Most significant are three cnginchouses which housed Cornish beam engines.

Jan 1, 1993

Myuna Colliery long term ventilation requirements were included as part of the overall planning of colliery construction and underground development. Ventilation, during the simultaneous sinking of two drifts and the downcast shaft, was accomplished by established methods of ducted exhaust and blower fans. Drivages for the 3 seam interconnections of shaft and drifts were ventilated by extension and duplication of the exhaust systems. Ventilation, for the below seam extension of the belt drift, construction of between seam and below seam bins, and the completion of a circular between seam drift, required a step by step changeover to a temporary main ventilation exhaust fan mounted adjacent to the top of the completed downcast shaft. The second, permanent upcast, shaft was commenced and colliery production started one seam at a time, using the transport drift, while the underground bins, belt and between seam drifts were completed. The uocast shaft was completed and a connection made in the upper seam, completing all contract mining and allowing the main fan to be erected. The permenent twin centrifugal fan system was installed, commissioned and test run to

Jan 1, 1983

As mining and extraction processes improve and lower grade ores become economic, mining for most ores have extended to depths beneath the zone of weathering oxidation created over geological history. These deeper openings expose sulphidic formations and reduced mineral species as either primary ore or simply as accessory or gangue minerals in the country rock. This is not new, underground mining for primary base metal and gold have long been familiar with these problems, as have coal and uranium miners. The change is simply that the number of mines exposing sulphidic waste rocks, tailings to the atmosphere and/or leaving behind dewatered sulphidic rock surrounding the mine void has increased the number of sites from where acid mine drainage (AMD) may emanate with consequential problems for the hydrological environment including downstream catchments (Miller et al, 1996). The principles of ecologically sustainable development (Brundtland, 1987) have been more or less ratified by all the developed nations of the world and this has led, amongst other things, to an expansion unprecedented in the research and documentation of means for achieving long-term environmentally acceptable stabilisation of solid wastes of all sorts. These have revealed that AMD problems can be minimised and even reversed in many cases by the integration or co-disposal of biodegradable organic wastes with oxidising sulphidic wastes (Elliott et al, 1996). This paper considers how this might be achieved at mine sites in Australia and the results encountered at some relevant sites.

Jan 1, 1997

Recent and on-going studies on the leaching of gold, the properties and activity of carbon, developments in the elution of gold from carbon, and methods of recovering gold from solution are reviewed. Emphasis is placed on Australian contributions, and their impact on gold metallurgy. Consideration is given to the future development of selective solvent extractants, ion exchange resins or alternative reagents for cyanide.

Jan 1, 1987

I WISH to express to the members of the Institute my sincere appreciation of the distinction which they have conferred upon me by again making me their president. It also gives me great pleasure to once more welcome the Institute to Mount Lyell.Since your last visit certain improvements in plant have been made, which I trust you will have found interesting, and which show that, though located in a remote corner of the world, we are abreast of the times.The opportunities which a recent lengthy trip to America has given me to observe the degree of interest which our local smelting practice continues to arouse in metallurgical circles make it seem appropriate that I should take advantage of your visit to lay before you some detailed information on the more practical features of pyrite smelting, particularly as carried out at Mount Lyell. There are only a few places in the world where the method is now being practised in approximate purity-only about half...

Jan 1, 1915