Search Documents

By D J. Corp

The Halmahera Contract of Work is a sixth generation contract held 82.5 per cent by Newcrest Mining Limited and 17.5 per cent by PT Aneka Tambang and takes in the Gosowong Project area. In 1991 Newcrest Mining Limited established a small exploration office in Jakarta and proceeded to seek exploration opportunities. The Halmahera area was identified as a substantial prospective ground position in a relatively unexplored area. In late-1991 Newcrest Mining Limited and PT Aneka Tambang agreed to explore in Halmahera. Initial field work commenced in July 1992. A vigorous ground reconnaissance programme led to the discovery of the Gosowong deposit a little over 12 months later in September 1993. In April 1997 the Contract of Work was approved covering much of the island of Halmahera. Between September 1997 and November 1998 activities were directed principally towards obtaining the necessary permits required to commence construction activities. Some particularly ambitious targets were set for achieving this outcome. An aggressive construction programme commenced in late-1998. Construction took place during a period of unseasonally high rainfall, which in itself presented additional challenges to the construction team. A key milestone for the project was achieved on 1 July 1999 when wet commissioning of the process plant commenced. Construction of the Gosowong Mine was achieved on time and within budget. A period of some six years elapsed from the initial discovery of the Gosowong deposit to the time of the first gold pour. Much of the permitting, construction and commissioning activity took place between September 1997 and July 1999. This coincided with a period of significant social, economic and political upheaval in Indonesia. During the construction period a high level of importance was placed on the structured recruitment and training of local people, as well as fostering appropriate community and local business development programmes in the communities nearby the project. Emphasis was also placed on environmental management with detailed long-term planning and progressive rehabilitation commencing during the construction phase. The permitting and subsequent development of the Gosowong Project has demonstrated that even during the difficult times, with commitment, it is possible for mining and exploration companies to conduct business in Indonesia.

Jan 1, 1999

By Patterson B. G

The small party of mining men who formed the original Mount Morgan Syndicate in 1882, commenced operations on the top of the mountain with what were practically nothing more than small hillside quarries, It was not until 1891 that underground stoping began, and open-cut mining therefore commenced with the commencement of operations. This hillside quarrying, however, seems to have been quite haphazard and unsystematic ; there is no trace or sign of any properly devised mining scheme. This can be seen plainly enough from an examination of old mine plans; for in less than five years after stoping was; adopted, the open-cut was down into the stoped-out ground. The following table, prepared from these old plans, shows the downward trend of the excavation in the past fiftyseven years:-

Jan 1, 1939

By Slechta J. J

An evaluation of a pilot scale Delkor horizontal belt filter at Bellambi's South Bulli Colliery showed high productivities and low moisture contents for a range of feed slurries. When treating flotation concentrate, a productivity in excess of 1000 kg/m2/hr (dry) at a moisture content of less than 22 per cent was obtained. The results indicated the belt filter had a capacity twice that of conventional drum or disc filters, and was capable of dewatering a very fine, thickened, classifying cyclone overflow slurry to an acceptable moisture content. The superior performance of this filter is discussed in terms of the factors influencing cake formation and the stratification of solids in the filter bowl of a conventional rotary vacuum drum filter.

Jan 1, 1986

The use of walk-through inspections, approvals and ad hoc investigations to ensure risk is kept within acceptable levels is reaching its limits of effectiveness. Further improvement in occupational health and safety requires a systems approach, and the use of Quality Management principles is an obvious basis for this. SafeGuard, a æbest practiceÆ model health and safety management system and audit criteria based on AS/NZS ISO 9001:1994, has been produced by the Department of Mines and Energy. Quality style audits of mine and quarry health and safety systems are now being carried out by the Inspectorate.

Jan 1, 1998

By T Christie, A Swain

Patterns of quartz veining in epithermal gold-silver deposits at Wharekirauponga, Neavesville and Ohui in the Hauraki Goldfield, have been analysed to determine the effects of different lithologies on vein distributions. At Wharekirauponga, quartz veins are hosted in rhyolite and minor andesite, with the andesite containing slightly higher gold grades. Local basement andesite, rhyolitic tuff and silicified black shale host gold-bearing quartz veins at Neavesville. At Ohui, quartz veins are hosted in rhyolite, rhyolitic tuff and andesite. Fractal analysis was used to quantitatively describe the distribution of veining. The fractal dimension (D) of veining in silicified tuff is 0.25, moderately silicified rhyolite has D = 0.23 - 0.26, clay-altered andesite has D = 0.3, strongly silicified rhyolite has D = 0.3 - 0.39, silicified andesite has D = 0.4, and silicified black shale has D = 0.43. The D values are related to the composition of the host rock, and appear to be controlled by its competency. Hydrothermal silicification results in increased competency and higher D values. Vein thickness frequency plots for different lithologies show that andesite at Ohui, and to a much lesser degree at Wharekirauponga, contains more thick veins than rhyolite and tuff. Gold grades show a strong to fair correlation with higher vein density in three drillholes at Wharekirauponga. The fractal dimension of veining is an important control on fluid flow and gold deposition within an active epithermal system. Vein systems with higher D have a greater density of veining which would have favoured increased fluid-rock interaction. Lower D vein systems have more clustered arrays. The increased fluid-rock interaction induced by a high D vein system, when combined with a reactive host rock, results in an environment which is highly favourable for gold deposition. This situation is seen in the andesite at Wharekirauponga.

Jan 1, 1994

There are many types of environmental audit: compliance, impact, risk and management audits; internal and external audits; single and multiple-project audits. All are becoming increasingly important in corporate management as new legislation confers increasing personal liability on directors, executives and staff of corporations and agencies in both private and public sectors.

Jan 1, 1990

Contract mining is an integral part of the underground and surface hard rock mining industry in all states of Australia. Contract mining is now makes a major contribution to the opencui coal industry in Queensland and New South Wales with Thiess alone producing over 16 million tonnes per annum with safety performances that most coal companies would be proud of. Contract mining is now attracting interest in the underground coal sector.

Jan 1, 1998

By McElrae AJ, McTaggart SM

The recent rapid escalation in computer use by mining companies, particularly in technical applications, can in part be traced to a growth in the availability of specialist packaged software. Such software, often developed by independent software companies provides economies of scale, end user orien- tation and breadth of scope imposed by market forces. This paper reviews the emergence of these companies and current software econo- mics before extrapolating present trends to consider the effect of future fourth gen- eration languages upon productivity.

Jan 1, 1983

After the last world war, management tended to change from an acquired skill more associated with experience than formal training, to a specific widely-recognised specialism requiring an involved formal education process.That process, of necessity, required the development of business schools, M.B.A. courses -indeed the setting up of professional chairs to deal with the intricacy of general management development.Management research burst forth bringing forward new and exciting theories which developed new techniques, tools and terms.

Jan 1, 1985

By Johnston G, Joyce C

The permitting of new mining projects has evolved into a highly complex process that must be carefully managed. Only by developing a thorough understanding of the issues involved and stakeholder interrelationships can successful strategies be developed that integrate the often competing demands of: ò regulatory requirements, ò commercial requirements, ò social/cultural needs, and ò technical issues. Properly implemented, this approach can result in: ò shortened approval timeframes, ò better project definition ò broad based community support, and ò favorably disposed government departments.

Jan 1, 1997

A number of forecasting methods are available to mine management to help predict the most likely outcome of some particular event thus enabling management to make more cost effective decisions. Three general classes of models can be used to predict future events qualitative, structural and time series, the most effective method in most cases being time series. Time series methods can be applied to predict future events from a series of past observations. Various time series techniques are reviewed with a comparison of their relative advantages and disadvantages.

Jan 1, 1980

By Hare G

The emphasis in Australia, until recently, has been on large scale mining methods with drive sizes in excess of 4.5 metres square and the acceptance of high dilution ratios, even when working in relatively narrow orebodies. The rising cost of extracting and treating the recovered ore and the lower prices available in the world markets has seen a growing trend to narrow mining methods.Traditionally narrow orebody mining has been carried out using hand held drilling methods and rail mounted boggers. Recent advances in mobile equipment now offers the operator of narrow method mines the opportunity to completely mechanise the mine from the drilling, through bogging to haulage, while maintaining minimal dilution in drive sizes to two metres wide or less.

Jan 1, 1993

The commonly used stainless steels, their properties and uses are briefly discussed.Two specific topics are then explored in more detai's to highlight development areas, the potential of which has been largely unexploited in mining milling, refining and smelting operations. The high strength to weight ratios achievable in austenitic stainless steels has been widely used in the transport industry to design high integrity light weight vehicles,especially railway carriages. This use has rarely been extended into other structural areas where highly aggressive environments could make stainless steel a cost effective material compared to protected carbon steels. The recently developed weldable ferritic steels are described and their potential in materials handling discussed. Particular attention is paid to 3CR12, a nominal 12% Chromium, titanium stabilised steel finding wide acceptance in the mining industry.

Jan 1, 1985

Process control computers are finding ever increasing applications within the chemi-cal and mineral processing industries.To purchase a system which fulfils both the immediate and future needs of operating, technical and management groups, requires an appreciation of the capabilities of the system software and the constraints which apply to user development of application software. Early decisions are then required as to who will develop and maintain the software. Rules and conventions must be determined and adhered to if the end result is to be an orderly, well structured and properly documented system. Software development and maintenance represents a substantial, and often hidden, cost. Getting it right the first time will avoid either a major re-work, or having to live with a system which is extremely diffi-cult (at the worst, impossible) to trouble-shoot or modify.

Jan 1, 1985

By Butcher NM, Walker GS

Argyle Diamond Mines Pty. Limited (ADM), manager and operator of the Argyle Diamond Mines Joint Venture (ADMJV) will recruit approximately 400 employees during 1985 to operate the new large-scale, open-cut diamond mine and treatment plant being developed at Argyle, in the East Kimberley Region of Western Australia. These employees will live in Perth or environs and will commute to work at Argyle via chartered jet aircraft. On site, they will be accommodated in self-contained single person's quarters, with central messing and recreational facilities. Rostering systems have not been finalised, but it is likely employees will rotate through a cycle of 14 days at site and seven-days on leave in Perth. ADM spent three years evaluating residen- tial options before deciding to commute its workforce from Perth. Another 70 senior staff will reside in Kununurra (the nearest established town, 250 km from Argyle) and commute to the mine daily by air.

Jan 1, 1984

In 1965, Peter Flawn author of the famous text-book on Mineral Resources (1966) published a paper in Economic Geology with the delightful title `Who took the `Economic' out of Economic Geology?'. He opened this most interesting article with the following paragraph:If one were called upon to cite an example of a fish out-of-water he could hardly pick a better one than a recent graduate of geology of an America university who is suddenly faced with the responsibility of evaluating or appraising a mineral property. And I venture to say that the 'ftsh' with a doctorate - even in economic geology - is not much better equipped than one holding a lesser degree. The new graduate with a major in economic geology probably knows the significance of the various sulphur isotopes, he surely knows a great deal about the chemistry of the ore forming fluids and he recites with ease the arguments which prove deposits are epigenetic rather than syngenetic. However he is a rare bird indeed if he knows anything about the economics of the mineral industry. The truth is that geologists who are engaged in evaluation work are largely self taught. I ask my more distinguished and experienced colleagues - `Has it always been this way? Who took the `economic' out of economic geology?

Jan 1, 1993

Australia is the dominant iron ore supplier to the Asian market, a position that began to emerge with the development of the Pilbara in the 1960s. Iron ore is now one of AustraliaÆs main commodity exports and is likely to remain so well into the future. The annual price negotiations are the focus of widespread comment and speculation by financial analysts, journalists and mining professionals. Much is written on the subject, but how much is understood? What is the process all about and what can mine managers learn from understanding the pricing mechanism? Every one of the major regional iron ore markets has its own characteristics. The focus here is Australian supply specifically to Asia, far and away the biggest and fastest-growing of these regional markets. The core of the paper reviews and explains the key elements and procedures that contribute to pricing iron ore in Asia, a market that has long been dominated by the Japanese steel mills (JSMs) and that is now feeling the full force generated by the rapid industrialisation of China. First, however, it is important to understand how this market has evolved over the past 40 years, and the key relationships that have shaped and continue to shape the iron ore price. A description of the essential technical and commercial factors follows. Each area is explained in some detail to provide an overall demonstration of the linkages and the importance of understanding the various influences on the pricing process.

Jan 1, 2006

By Browning E. J

The application of conventional dust control systems in British Coal mines has considerably reduced the incidence of pneumoconiosis. A number of new techniques have been developed involving extraction close to the cutting heads of mining machines which will be capable of controlling airborne dust with the greater intensity of production necessary in the present economic climate.

Jan 1, 1988

In the current climate, there is a real need to bridge the gap between theory and the real world mining considerations, and develop viable, cost-effective, high performance thickeners. With a greater need to extract profits from both difficult-to-process ores and lower grade orebodies, coupled with the necessity to produce 'greener', less water intensive technologies, suppliers need to take current thickener designs to the next level and into the 21st century. The complexity of 'getting it right' within a thickenerÆs feedwell, the 'nerve centre' of the thickener, is no small task. Delivering dilution water and mixing this water with incoming feed slurry, addition of flocculant, maximising flocculant-slurry interaction to build aggregate size, minimising unabsorbed flocculant percentage, volume average of solids volume fraction, momentum dissipation ratio, dilution recycle ratio, volume average shear, maximum shear rate at exit, aggregate size on exit, uniform discharge profile and more ù all of these need to occur in the right order and in the right proportions within the feedwell. This paper discusses the genesis and evolution of a new feedwell design, the first major innovation in the thickening industry in over 15 years.

Jan 1, 2008

By N S. Weerasekara, S Town, E Lessing, J A. De Torres

Philsaga Mining Corporation (Philsaga) had three main aims in converting their lining system from steel to metal cap. They wanted to increase mill availability, minimise localised high wear and optimise particle breakage to deliver increased efficiency within the milling circuit. Combining Discrete Element Method (DEM) modelling and empirical interpretation of liner wear resulted in a rigorous approach to understanding the impact of mill liners on overall mill performance. This new understanding was subsequently used to not only derive a new lining design to optimise performance and thereby improve overall plant economics, but also to guide further lining development.In this work, detailed DEM modelling, developed from actual plant data, together with optimising liner design for wear paved the way towards the installation of a Metal Cap lining system at Philsaga’s Ø6100 mm SAG Mill. The results were a reported increase in SAG mill throughput of 16 – 20 per cent due to improved breakage through more efficient use of installed power, a reduction in localised high liner wear with overall increase in liner life and reduction in liner replacement time. Site also reported an increased gold recovery of 2 per cent which the improved breakage might have contributed to. This paper will present the design challenges and compare the Metal Cap lining systems performance against Steel lining system. CITATION:Weerasekara, N S, Lessing, E, Town, S and De Torres, J A, 2018. Metal cap versus steel lining system at Philsaga Mining Corporation’s Ø6100 mm SAG mill, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 653–664 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018