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By English W, Poppit I

COALEX Pry Limited operates two underground steaming coal mines on the western edge of the Sydney Basin near Lithgow, New South Wales. Baal Bone Colliery uses longwall technology for an output of over two million tonne/year while Clarence Colliery currently uses continuous miners and breaker line supports for an output of two million tonnelyear.A computerised geological database and modelling system has been implemented to service these mines routinely, as well as several outlying prospects. The database is constantly upgraded for drillhole information, surveyed spot levels on the surface and underground, quality sampling details, surveyed mine workings and geological mapping. This information is edited on a routine basis, allowing dynamic modelling of key aspects of geology for ongoing operations.

Jan 1, 1991

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

By He BQ

Static attachment of bubbles to solids is contrasted with dynamic attachment in flotation cells. The times of contact during particle-bubble collisions in dynamic attachment are compared with the induction time determinations and the kinetics of thinning of the liquid films separating solids and bubbles. The thinning is examined mainly in terms of electrostatic and dispersion (van der Waals) contributions to the disjoining pressure existing in the films. The local heterogeneity (on a molecular scale) of charge distribution invariably present at all interfaces (even at conditions of zero zeta potential) calls for some means to minimize possible electrostatic repulsions which arise when the electrical double layer at the air-bubble interface begins to overlap that present at the solid surface, on encounter between particles and bubbles. It is postulated that dipoles of frother molecules, owing to their ability to "flip over" (polarise), replace localized electrostatic repulsion by attraction within fractions of a milli- second, as long as the structure of the frother molecules is sufficiently "bulky" to maintain diffuse films (of mixed collector-frother) at the air/liquid interface of bubbles. The relaxation times of dipoles (signifying their "flipping over" ability) have to be shorter than the collision times between particles and bubbles for particle-bubble attachment to be facilitated under dynamic Conditions.

Jan 1, 1984

By C Vejrazka, A Wyllie

A common problem faced by underground mining operations around the world is airborne dust sourced from production and auxiliary processes. In most underground mining methods, air is generally directed through a limited number of drives and is thus more effective at carrying dust away from operational areas quickly. In a block caving operation, there are a number of ways to set up ventilation systems. In its simplest form the air is entering the extraction level through access drives and then split over the number of extraction drives—based on the pressure differences—without being regulated. This is the case at Northparkes Mines. Larger operations and panel caves most often utilise designated ventilation levels and ventilation raises with some form of regulation to ensure adequate airflow to all work areas.Northparkes Mines utilise electric loaders as a productive means to transport ore to the run-of-mine (ROM) bin, which have the added advantage of allowing the mine to require less airflow through the extraction drives as dilution of exhaust gases is no longer required. Dust was controlled during the operational period of the previous two block caves by using water spray bars in each of the drawpoints, which were seen as the main source of dust. These drawpoint spray bars only wet the surface of muck piles and require a lot of water to achieve an effect on the overall air quality. The drawpoint sprays can be remotely operated from mine control, whenever a loader is sent to bog a particular drawpoint. A significant amount of airborne dust is also generated during loading as rilling of material occurs, with further dust being generated during tramming and dumping activities as only limited mixing of the water and ore occurs. The water sprays are ineffective at precipitating dust that has already become airborne.When built, the currently operational E48 cave was fitted with drawpoint water sprays. As the cave is in a different orebody with higher silica content, the water sprays were not able to keep airborne dust and thus silica quantities under control efficiently. It was therefore necessary to find more sustainable solutions. The problem was further intensified by the concurrent load-haul-dump (LHD) processes across multiple extraction drives and tipping points, as well as secondary breaking, using non-explosive blasting and development activities occurring nearby.This paper describes the practical approach taken at Northparkes Mines to reduce personal dust exposure on the E48 extraction level. As the extraction level is one of the main contributors to airborne dust at the mine, it is believed that much can be learnt by focusing improvement efforts initially on this part of the mining process and later applying the effective solutions in other parts of the mine.CITATION:Vejrazka, C and Wyllie, A, 2014. Reduction of airborne dust on the E48 extraction level at Northparkes mines, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 227–232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

Separating Particles by Horizontal Deflection in a Paramagnetic Fluid This paper describes the horizontal deflection behavior of particles in paramagnetic fluids under a high-gradient superconducting magnetic field. Movements of single particle were observed experimentally and indicated that they could be deflected to different positions. Based on these results, the behavior of groups of particles from ore samples was examined in the superconducting magnetic. It was found that these particles could be deflected and settled at a certain position due to the combination of gravity and magneto-Archimedes forces as well as a lateral buoyancy (displacement) force. Mineral particles with different susceptibilities and/or densities could be deflected to different positions, thus producing groupings of similar types of particles. The work described here, although in its infancy, could form the basis of new approach to separating particles based on a combination of susceptibility and density.  

Sep 13, 2010

By Read T. A

PART 1The quantity of dust present and the methods used for suppression of dust in metalliferous mines has, in recent years, received considerable attention from mining engmeers in various parts of the world. Shortly after the publication of the General Report of the Miners' Phthisis Prevention Committee, South Africa, in 1916, the officers of the Broken Hill South Limited started investigations into the conditions of the dustiness of the air in the underground workings. As the methods used are not generally known in Australia, the writers are of the opinion that the present is an opportune time to place them before members of the Institute. A large amount of the subject matter of this paper has been drawn from the 1916 and 1919 reports of the Miners' Phthisis Prevention Committee, South Africa, the paper of Mr. Innes published in "The Chemical, Metallurgical and Mining Society of South Mrica"; also various articles appearing in the Journal of Industrial Hygiene, and the American Journal of Public Health. A great deal of research work into the cause, prevention and estimation of mine dust has been made by the Miners' Phthisis Prevention Committee of South Africa, and officials of the United States Bureau of Mines. The writers considered it advisable to begin the investigation at the South Mine with apparatus and methods developed by the South African Committee.Through the Australian agent of the Cape Explosives Company, inquiries were made preliminary to procuring the necessary apparatus for the determination of dust, from South Africa. The writers then learned that the older gravimetric method used by the Phthisis Prevention Committee was likely to be superseded by the konimeter...

Jan 1, 1922

All large open pits in Australia have been mined, or are planned to be mined well below the local water table. This raises several issues that impact on mine safety, mining costs and regulatory approvals. Some pits will be æwetÆ, where they are mined through permeable horizons and where there will be measurable groundwater inflows. These will require some form of dewatering. There may also be some difficulties in the disposal of excess water. Other pits, may be ædryÆ, where they are mined through impermeable material and there are no measurable groundwater inflows but where there are stability issues related to hydrostatic pressures within the pit walls. These may require some form of depressurisation. Some pits are a combination of both. Effective management of groundwater inflows and groundwater related stability issues and the development of cost effective and environmentally acceptable dewatering and depressurisation systems requires an understanding of site specific hydrogeological conditions and practical experience in what works best for different conditions. The presentation will include an outline of the key hydrogeological factors that impact on large pits, practical methodologies for achieving dewatering/ depressurisation, and some case studies from the Goldfields, Pilbara and North Queensland.

Jan 1, 2003

By Dods G. H, Hewitt W. V

Ashton Mining Limited is currently one of the active companies undertaking gold exploration in Indonesia. Presently 7 Contract of Work areas are being explored for hard rock and alluvial gold. Hard rock exploration is focussed on the Tertiary volcanic arc terrains in which a variety of epithermal mineralisation styles have been identified. At the regional stage remote sensing techniques using Landsat, Spot and SLAR imagery where available, and photogeological studies are carried out in parallel with regional reconnaissance fieldwork programmes. These involve geological mapping and geochemical drainage sampling. Remote sensing techniques have proven useful in both the extrapolation of known geology and the identification of tectonically favourable settings as controls to mineralisation and volcanicity. The variety of mineralisation styles and settings is reflected in the highly variable geochemical signatures encountered. This has necessitated the refinement of sampling methods and sample preparation techniques for pan concentrate, stream sediment and soil samples in specific project areas. At the detailed prospect stage, mapping with particular attention to structural controls, wallrock alteration assemblages identified by petrog- raphy and XRD clay mineralogy, have proved useful in focussing drill targets. Drilling to date has utilised conventional diamond core drilling methods, the use of lightweight, man-portable "Winkie"-type rigs and hammer auger bedrock sampling systems. Geophysics methods successfully employed on various projects have included airborne magnetics and radiometrics, detailed ground magnetic surveys, VLF-EM and SIROTEM.

Jan 1, 1991

Since its commercial in Australia at Broken Hill in the early part of the 20th century, the flotation process has grown to become the single most important minerals separation method available to mineral processing engineers. Statistics on flotation are impressive both in terms of growth of tonnages treated and in terms of the variety of separations accomplished. Because of the steady decline in the grade of ores and because many of the ores remaining are finely disseminated mixtures of minerals (many of them in a highly oxidized state) mineral processing scientists and engineers are now con- fronted with the problem of improving and modifying conventional flotation techniques so as to be able to effic- iently process these more refractory types of-ores. The flotation process did not come into being as the result of an intensive fundamental research effort but, in a similar way to so many other methods used in the processing of raw materials, it was developed over the years by the continued application of empirical methods. As a result, most of the basic research in this field has long been concerned with the problem of explaining why the existing process works so well. We are now at the stage where any further substan- tial extension of the flotation process will demand a more profound understanding of its fundamental principles. Current knowledge of flotation fundamentals is still far from the stage where processes can be designed, optimized, and controlled from first principles. The extensive

Jan 1, 1984

By S M. W Rajaratnam, P Varma, T L. Sletten

Mining employees undertaking shift work are at considerable risk of experiencing sleep disturbances and circadian rhythm disruptions. In the complex, high-risk environment of mining, these sleep and circadian disruptions lead to adverse impacts on employee health, alertness and safety. Evidence-based tools that effectively target improvements in sleep health amongst shift workers are needed. Variability in work hours and individual differences in the response to shift work mean that a ‘one-size-fits-all’ solution is often insufficient in complex work environments. Currently no interventions provide tailored support for shift workers based on their rosters, personal commitments and sleep habits. Existing technologies, such as smartphone applications and watches, allow sleep monitoring, but their strategies are targeted towards night sleepers, which does not translate to shift work contexts. To address this, our team has developed an innovative digital tool that implements biomathematical models to provide automated, personalised sleep and circadian intervention strategies to optimise sleep, alertness and performance during shift work. The tool uses mathematical models of sleep and alertness regulation that provide physiologically optimal times for an individual to sleep when experiencing circadian disruption. This program of work included co-designed development of a world-first app with shift workers and the examination of the preliminary efficacy of the intervention for improving sleep, alertness and performance.

Apr 16, 2024

By Tonks E. E

The earliest discovery and mining of coal in the northern area of the Greta Coal Measures at Anvil Creek in 1862 was by William Farthing, however, some official records attribute the discovery to Thomas Frost in 1864. Frost's discovery was examined by William Keen, government examiner of coalfields, and further prospecting was carried out. This was followed by the pioneering work of C S Wilkinson, government geologist in 1884. Subsequently in 1886 C S Wilkinson entrusted a detailed survey of the coalfield to the then geological surveyor, T W Edgeworth David.The outcrop of the Greta Coal Measures around the Lochinvar dome was mapped by Edgeworth David and as soon as he reported his discovery, the Department of Mines reserved in the interests of coal mining an area of 23700 acres, which extended between what became the South Greta and Abermain No I Collieries.

Jan 1, 1993

HoistEM is a helicopter-towed time domain electromagnetic system. This paper presents details of the towed array structure (the Hoist) as well as a description of the instrumentation. A comparison between HoistEM and ground TDEM (from which HoistEM was derived) is given. Over 50 000 line kilometres of HoistEM have been completed to date and datasets for structural mapping, nickel, base metals, manganese, ground water and bathymetry are presented and discussed.

Jan 1, 2004

By MacLean L

In 1975 the Commonwealth Government established import parity pricing for all liquid hydrocarbons discovered after the 16th September, 1975. These discoveries were termed "new oil" to differentiate them from existing discoveries and production. Overnight the price of the product being sought trebled, resulting in greatly enhanced economics by increasing the potential returns on existing prospects and by making smaller plays economically viable. After 18 years of drilling, the offshore Gippsland Basin has attained a moderate level of exploration for a basin of its size. Fifty seven prospects have been drilled within the basin but only a few of these were drilled along the southern and northern margins, while the deep water areas along the eastern margin have remained virtually undrilled following the Hapuku-1 oil discovery. The major hydrocarbon accumulations within the basin are trapped beneath the Latrobe Unconformity surface and exploration has largely concentrated on this single play in areas immediately adjacent to the major producing fields.

Jan 1, 1982

The carbon-in-pulp (CIP) process is now well established in the South African gold industry, with a total of over I million metric tons of material being treated each month in six large plants. This tonnage is derived from ground ore, from filtered pulp, from calcine, and from reclaimed sand-tailings dumps. With this new process and the new large plants, those concerned with CIP are experiencing a learning process, since each new plant presents a different set of problems to be overcome. The knowledge and experience gained from these plants is being shared, and will be of benefit in the design and operation of new plants. The CIP process can be subdivided into the following unit operations: prescreening at a fine size, adsorption, acid-washing and elution, reactivation, and electrowinning. Results concerning each of these unit operations, which were obtained from pilot plants and from large-scale CIP plants in South Africa, are presented. The latest developments in each of these areas is summarized. Tables that are included as an appendix contain some information concerning the equipment in these new CIP plants plus operating results from some plants.

Jan 1, 1982

The future of the United States (US) mining industry will be affected greatly by recent coal mining disasters. These have resulted in new legislation which will have an impact on mining economic costs as well safety and health of miners. This paper discusses the changes that new legislation and regulations are making to the industry and current research that is producing technologies to make mining safer and will likely impact the future of mining.

Jan 1, 2008

By Yambu J, Titus K

Geotechnical investictations and monitoring have been integral to development of the Porgera Gold Mine. The steep, unstable terrain has required a program for monitoring of slopes and foundations which includes survey stations, borehole inclinometers and piezometers. Case studies of the Maip Pass landslide, Yakatabari land-slide, Anawe Plant Site CIP pond excavation and batter, and a load test study for mine waste dumps are presented.Monitoring is needed to ensure that geotechnical risk is kept to a minimum. A vigilant program will be required for the life of the mine.

Jan 1, 1994

By Abdulhadi H. M, Soliman S. A

The Western Desert of Egypt is a part of the arid Great Sahara of Africa which extends from the Nile Valley in the east to the Atlantic Ocean in the west. It is covered by a sedimentary sequence of Mezozoic and Teriary rocks. Recently this part of the country (about 65% of its surface area) has attracted an increasing attention in the plan of finding new agricultural and industrial communities outside the crowded Nile Valley. The plan aims to reduce the high population density in the narrow Nile Valley and to cover a considerable part of the increasing food demands in the country of Egypt. Accordingly, the groundwater exploration work in the Western Desert has been remarkably increased in the last decade, however it is still limited compared with the vast area of the Desert. The present work is a part of the groundwater exploration in the 6th October City, a new community located at 40kms west of Cairo. The rock exposures belong to a sedimentary stratigraphic section starting from the Cretaceous in the east to the Pliocene in the west. The Cretaceous outcrops due east are attributed to an almost N-S uplift and forms a thick massive limestone plateau which separates the present area from the Nile Valley. The Teriary section in the west have alternations of different porous formations such as the sands and sandstones which may acquire a good potentiality of groundwater resources. The previous groundwater exploration work included combined geological and geophysical investigations followed by exploration drilling. Although the area lies directly to the west of the Nile Valley, the discovered groundwater is saline and located at deeper reserviores compared with the groundwater in the Nile Valley. This groundwater was described as marine fossile water by the oil companies working in the Western Desert. From the geological point of view, it is believed that the Cretacious massive limestone plateau, in the east, roots to a depth which far exceeds the groundwater levels in the Nile Valley and acts as an impervious barrier between the aquifers in the Nile Valley and the area under investigations.

Jan 1, 1988

By Y Bissiri

The ever increasing demand for metals and minerals is putting significant pressure on current mining companies to find more ore. As these companies explore and mine, the future appears to be to go deeper and deeper underground. With depth, however, comes ever increasing costs as infrastructure such as hoisting, ventilation, the movement of workers and materials increase in size and scope. Further, the actual rock mass becomes prone to destruction through rock bursts and the heat generated becomes a major issue resulting in extreme expenditures in cooling plants and some of the biggest air movers in the world. All these issues result in dramatic changes in both capital and operating costs, subsequently making cut-off grades rise. As this trend continues there is an economic limit to how deep one can go, resulting therefore in a severe shortage of accessible ore deposits to mine. This paper discusses the need for larger marine robotics technology and presents the state-of-the-art in current research in underwater tele-autonomy, specifically the development of high bandwidth optical communication networks critical to any future activities (mining, construction, etc) underwater. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

ATTENTION has recently been directed to the subject of dust production and methods of allaying same in the Broken Hill mines, so that the time would seem opportune for the local branch of the Institute to discuss certain features of an important phase of the health question in connection with underground work. Tests conducted in the Broken Hill South mine and at other mines at Broken Hill have shown that the ordinary operatioils of mining, such as boring, blasting, and shovelling, may be accompanied by the production of considerable dust unless water is judiciously used.In South Africa·dust particles under 5 microns size are regarded as dangerous, becailse they are so small as to be invisible to the naked eye, and wm esc'ape the protections set up by nature in the nose and throat, and thus may be inhaled in large quantity. A micron is 1 25000th part of an inch. This paper contains an account of the work done on the Broken Hill South mine chiefly, though some tests were done on other local mines.An acknowledgment is due to Mr. T. A. Reid, of the Broken Hill South mine, who conducted some of the tests herein mentioned, and under whose supervision most dust counts were made. Numerous dust samples have been taken by means of thekonimeter, an instrument designed by Dr. Kotze, the Government mining engineer of the Union of South Africa, and fully described...

Jan 1, 1921

By Dunn J, Nguyen G, Graham J

A pyritic gold concentrate from the Golden Mile, Kalgoorlie, was roasted over a range of temperatures in a pilot scale fluid bed reactor. The calcines were subsequently cyanide leached. Mineralogical studies of the con- centrate, calcines and leached residues were also undertaken. Calcines produced at 500'C gave the poorest gold extractions and high cyanide consumptions. Gold recoveries of approximately 90 per cent were obtained from calcines produced at 550-600'C but higher roasting tempera- tures resulted in an increase in the residual gold content of the leached calcine. There is some evidence of flash smelting of the pyrite at the higher roasting temperatures and encapsulation of gold particles. Mineralogical examination of the calcines shows that the mechanism of oxidation is temperature dependent. At 500'C pyrite is directly oxidized to hematite with a concentric layered texture which appears to inhibit lixiviant access to enclosed gold particles. At higher temperatures the conversion sequence pyrite-pyrrhotite-hematite produces a spongy calcine which al- lows easier penetration by the leaching medium.

Jan 1, 1991