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The treatment of steels with acid solutions for the removal of oxide products represents possibly the largest outlet for chemicals in steel processing. Organic pickling inhibitors are required to prevent base metal attack by these acids otherwis

Jan 1, 1980

By A M. Myrvang, B Nøst, N Q. Trinh, I S. B Bergh

The iron ore producer Rana Gruber AS is situated in northern Norway just below the Arctic Circle, and has been producing hematite and magnetite concentrates for more than 60 years. Since the late 1990s, the major part of the production comes from a sublevel stoping underground operation after many years of open pit mining. Despite moderate mining depth, the operations have experienced considerable rock stress problems due to quite high tectonic, horizontal stresses. To manage the problems, comprehensive rock mechanics investigations have been carried out by SINTEF, a major contract research organisation. This has included in situ rock stress measurements, laboratory investigations and numerical modelling. Based on this and practical experience, satisfactory design of vertical and horizontal pillars was achieved. At depth, the ore width increases from 30–40?m to more than 100?m. This, together with a major planned increase in production, called for a change of the mining method. After thorough investigations and considerations, it was decided to change to sublevel caving, very much like the LKAB system. The development of the new system has been closely followed up by rock mechanics measures, including 3D numerical modelling and comprehensive monitoring of deformations and rock stress changes. To achieve a satisfactory caving of the hanging wall, all vertical and horizontal pillars in the sublevel stoping area had to be removed. This has been a challenging task, and the development of the caving has been slow until recently. However, now the caving develops satisfactorily.CITATION:Bergh, I S B, Trinh, N Q, Myrvang, A M and Nøst, B, 2014. From sublevel stoping to sublevel caving at Rana Gruber, Norway – rock mechanical aspects, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 323–330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

A brief introduction is given of the scale and of some special features of South African gold mining; it is noted that great depth of mining and narrowness of the reefs, and hardness and abrasiveness of the rock are the main sources of the problems of the industry. The most inhibiting problems are: Excessive rock pressure occcurring in conjunction with rockbursts, hot and humid working places due to high virgin rock temperature and auto-compression of the air, and low level of productivity. Conventional solutions applied ordinarily in mining do not promise to eliminate, or even alleviate, these difficulties.

Jan 1, 1985

By Cusack BL

The addition of cement to underground backfill at The Zinc Corporation, Limited and New Broken Hill Consolidated Limited, Broken Hill commenced in 1967. This resulted in a deterioration in metallurgical performance with increased loss of lead and zinc to residues at each concentrator. Investigations to determine the cause of the problem and methods to counteract it have been undertaken. This paper outlines the effects of cement on lead-zinc beneficiation at Broken Hill and presents an interim report on attempts to overcome the metallurgical Deterioration.

Jan 1, 1970

By Maru Y

The use of mercury for amalgamation has been an integral part of the small-scale gold mining industry in developing countries owing to its low investment cost, simplicity of the technique and high gold recovery. However, its impact on health and environmental hazards have not been given the attention they deserve. In spite of the growing awareness and concerns over the mercury pollution problem by regul-atory authorities, precautionary measures such as bans on the use of mercury in some countries have been largely ineffective.This paper first reviews some of the mechanisms of mercury poll-ution, and mercury toxicity which varies according to its oxidation state. It then describes how mercury released to the atmosphere would go through the "Mercury Cycle". Compar-isons have also been made with previously measured mercury levels in small scale Papua New Guinean miners with their counterparts in other developing countries.

Jan 1, 1994

By Mishra S. N, Mishra R, Sen P. K

Control of silicon in produced through the submerged-arc furnace can result in reduced power and coke consumption in addition to improving the quality of the hot metal. A thermo-chemical analysis of the production of ferro-chromium was carried out to devise strategies to control the recovery of silicon during the manufacture of ferro-chromium. The presence of three thermochemical zones in the furnace with respect to the reduction of silica was recognised from this analysis. Any strategy for the control of silicon recovery has to take cognizance of these thermochemical zones. The effect of various strategies on the silicon level in the hot metal have been evaluated. Possible strategies, such as the reduction of coke level in the charge; the replacement of quartz; pre-reduction of the ore and the control of the temperature profile are discussed in this paper.

Jan 1, 1999

Over the past 18 months the De Beers Consolidated Mines Ltd operations have made a concerted effort to move away from using the traditional shock tube initiating systems. These systems are being systematically replaced by the use of electronic delay detonators (EDD). Various trials were conducted in both host rock and kimberlite rock masses to improve tunnel advance as well as to optimise delay timing during trough openings (Ngoma et al, 1999; Mohle, 1999; Baltus, 2000). The high cost of EDDÆs, when compared with traditional initiation systems, led to a number of detailed studies being conducted on the mines where EDDÆs were being used. These studies aimed to quantify the additional benefits when blasting with electronic detonators. The studies showed that the change was justified on the basis of increased quality control and reliability gained through the use of EDDÆs. However, these benefits attract other related benefits, like fragmentation control, and backbreak reductions. When compared to the shock tube initiating systems the increased development face advance and the reduction of oversize during production blasting using EDDs, compared favourably to the less costly systems. As blasting engineers gained experience and confidence in the use of the system bigger blasts were initiated in mass under-cut blasts and slot raise development, by using multiple hole firing and second delay periods between holes. In the open pit and sublevel open stope mining methods the control of the fragmentation distribution and the effect of the mass of explosive detonated during a blast is detrimental to the loading and hauling production rates and the stability of the rock mass behind the blast. With a stable rock mass the bench cutting can be executed to establish steeper overall slope angles leading to large cost savings due to a reduction in waste stripping. It is the purpose of this paper to indicate through quantification that the use of the EDDs as an initiating system improves all-round blasting performances and assists in meeting customer requirements. The customer being the ore treatment plant.

Jan 1, 2001

By B Hall

The authors have undertaken many independent mine optimisation and operational improvement projects at Australian and international mining operations over the past decade. This work has provided an understanding of the underlying practices responsible for the good long-term performance of some operations, and the failure of others to achieve their objectives. Good long-term performance, and value creation can be achieved through a logical and rigorous process of identifying the optimal mine plan (æThe PlanÆ) that delivers the corporate goals, establishing appropriate performance measures that are aligned with these goals, and ongoing monitoring of compliance with the established targets to ensure the operation reliably achieves The Plan. A number of practical methods have been developed and implemented to assist mining operations deliver their corporate goals. This paper outlines some of these methods, providing some fundamental guidelines that will assist in the establishment, and reliable achievement of The Plan that delivers the corporate goals.

Jan 1, 2006

David Pollard will raise this matter in more aetail in a later paper, but mere are some obvious points that I wish to make. It is a relatively straightforward exercise to assess the competency at a low level in the workplace where the consequences of a worker's actions can be observed immediately. Assessing competency at higher levels which may involve creative, planning, design or supervisory functions is more difficult, especially where managerial responsibility and accountability for the output of others is involved. This is generally the case with the daily activities of most mining professionals, whether they be in operations, in a consulting capacity, in research, or in government.

Jan 1, 1994

By J G Bastias

It is sometimes necessary to resort to extremes in order to call attention to something that is pertinent to safety in mining. When some of the experts in occupational safety talk about this topic, they usually refer to a 'regulation' established by the Romans which stated that, due to the health hazards, usually death, no Romans but only slaves should work in mining. Since the time of the Roman Empire, a lot of ground has been covered in the field of mine safety. Nowadays, it can be said that occupational safety is being seriously addressed, with the result that the number of mining accidents has reduced dramatically, fatalities in this industry are less frequent, and the rate of accidents compared with other activities, such as construction or fanning, is low. This achievement has been possible initially through government legislation and by procedures established by the mining companies themselves. However, the dilemma for government is whether to regulate and if so, how much. It is pleasing to observe that most companies are establishing working procedures which conform with new government legislation, placing strong emphasis on the duty of care for mine employees. There will always be some regulatory aspects of legislation, and perhaps the best example of this is in the use of mine hoists where there are no international or Australian standards, and the regulations applied are of an empirical nature that err on the side of safety.

Jan 1, 1994

By Tapp BA

Australia, considered an energy and mineral resource rich country, is poised on the verge of a major mineral industry 'boom'. It has been repeatedly emphasised that this growth in the mineral industry will form the basis of future economic development. Currently the mining and mineral processing industries use some 32% of the annual primary energy consumption in Australia. This share, although large even now, will increase with the realisation of the 1980's production expansions to 40% by 1985. Two metal industries dominate the energy scenario; iron and steel and aluminium. Major expansions in the local industry will be dominated by the aluminium industry. This highly energy intensive industry has planned major increases in metal production throughout the eighties. The implications of exporting cheap energy to pay for expensive oil imports, the ramifications on Australia's infrastructural ability to supply these major energy needs and the other options that might be

Jan 1, 1981

By Stewart C. A

The Northparkes copper-gold project is being developed in Central Western New South Wales approximately 30 km NNW of the town of Parkes and approximately 350 km west of Newcastle. The project is a joint venture between North Limited (80 per cent) and the Sumitomo Group (20 per cent). North is the manager. The basis of the project is three copper-gold orebodies, the northern two of which are being mined by conventional open cut methods with the third and largest orebody at the southern end of the lease to be mined by block caving. A fourth mineralised body has been identified in the centre of the lease. While further evaluation of this deposit is required it would appear to be amenable to block caving. Oxide caps of gold ore and copper-gold ore over-lie the two northern orebodies. Development commenced with the construction of a carbon-in-pulp (CIP) plant to treat the oxide gold ore. Construction of a flotation plant to treat oxide copper-gold ore and sulphide copper-gold ore is underway. When full-scale operation is achieved late in 1996 the plant will treat 5.0 million tonnes of ore per year of which 1.1 million tonnes will be open cut ore and 3.9 million tonnes will be block cave ore. In terms of annual ore tonnage the underground mine will be the largest metalliferous mine in New South Wales and the second largest in Australia.

Jan 1, 1995

The perennial challenge facing mining and minerals operators is to improve productivity, usually by a combination of cost reduction and performance improvement. In a typical production situation involving mining and processing activities, the standard approach has long been to seek improvements in each activity, effectively in isolation from each other. However, the realisation is growing that there is considerable potential to achieve really substantial productivity gains by much improved integration of mining and processing with the key being to consider what is best in the total sense. Some of the linkages between fragmentation in mining and downstream processing are considered in this paper. These linkages involve technical, operational and economic Considerations.

Jan 1, 1997

The optimization of management structure systems for coal mines is undertaken with the use of economic and mathematical models of the monitoring, manufacturing, and functional subdivisions of the systems. The main para- meter to be minimized is economic loss result ing from organization faults and this is achieved, in part, by optimum distribution of both technological objects and engineering and technical personnel. Models used are of the "gated" type, parameters for which are derived from analysis of manufacturing processes and from automatic information systems. The use of these models ofmanagement structures is only part of the process of optimization of those structures for coal mining operations.

Jan 1, 1977

Over the last thirty years production of heavy minerals from Australian deposits has dominated the world market. The main incentive has been to suoply the raw material for titanium dioxide based pigments. These ~ninerals include ilmenite, rutile, leticoxene and more recently, synthetic rutile. Inevitably the viabilit/ of developing placer type deposits has seen influenced by other heavy minerals present, such as zircon and monazite, but these have been of secondary importance. For most of the sixties and seventies, Australia supplied the 'najority of free world rutile and zircon, and a large proportion of the ilmenite. With the run-down of rutile- rich reserves in eastern Australia, the emphasis has s:iifted in several countries, including Australia, to fill }the gap with i l Wen i to and its derivatives, leucoxene, synthetic rutile and titanium rich slag. over the next 15 - 20 years, as high grade beach placers in Western Australia are mined out, less traditional sources for mineral sands products will be opened up. Low grade placers (particularly those dominated by ilmenite) will be reassessed in Australia, U.S.A., Africa and Asia, and exploration will shift from beach and dune environment, to heavy mineral concentrations in alluvials, lake deposits and continental shelf deposits. At the same time, production of anatase and bastnaesite will be expanded, as required, from the huge resources contained in carbonatites in 3razil, U.S.A. and China.

Jan 1, 1986

By S Morrell, D Clark

æMine to MillÆ improvement involves optimising the chain of rock breakage processes from the in situ rock in the mine to the output of the concentrator. A growing number of paper studies and case histories from metalliferous mines (AusIMM, 1998; JKMRC, 1998; Clark and Scott, 2002) demonstrate that generating more breakage in the pit and the primary crusher can lead to benefits to milling that result in significant improvements to the economic performance of a mining project. However, unless the ævalueÆ of doing this (benefit over cost?) can be appropriately quantified, the approach cannot be effectively managed and the increases in blasting and monitoring costs cannot be justified.Mining operations have traditionally been organised into the separate departments of geology, mining and processing based on the specialist skills required and the different professional disciplines involved. Process optimisation across these boundaries has commonly been frustrated by management requirements to minimise the costs incurred by each department without adequate reference to the ævalueÆ being created. Companies have tended to discard positions that provide a technical over-view of the value chain, reducing the number of people with the opportunity to influence practices across these process boundaries.This paper discusses these issues and identifies measures required to quantify and manage the ævalueÆ provided by æMine to MillÆ improvement generated by the intense blasting of ore.

Jan 1, 2002

Delivered by K. B. Gross at the First Ordinary Meeting of the Australasian Institute of Mining and Metallurgy, August 18th, 1952.Mr. President, Ladies and Gentlemen:Confronted with the task of reviewing the progress of Mount Isa Mines Limited, since the inception of the Company 28 years ago, I soon found that effective coverage was a task beyohd me, if I were to confine the address within the limits of time allowable. Faced with the alternative, a summary, that could only fail to -do justice to the subject, I turned elsewherl? for inspiration and found it in Chester Wilmot's book "The Struggle for Europe". Those of you who have read this masterly contribution to the literature of World War II will recall that he takes us, most dramatically, behind the scenes and we learn of the thoughts and ideas that were uppermost in the minds of both allied and enemy leaders at times when decision's that profoundly influenced the course of the war were taken. I felt I could safely follow this rather novel approach to my own problem. Strengthened by the realisation that the technical achievements of the Company have largely been covered over the years, and that the results of our labours are mainly here before you, I have attempted to liven up my modest canvas by going behind the scenes, and have sought to deal with ideas and the reasons for important decisions, rather. than to embark upon a purely descriptive essay.If then, you will bear with me, we shall skip back through the years to the days of struggle that our President's address has so aptly covered, and find that one man's ideas and faith stand out beyond all others. W. H. Corbould must always be credited with having founded the enterprise, for he correctly appraised the potential of the struggling prospect and foresaw what could be done, despite the handicaps of geography, climate and need for heavy expenditure.

Jan 1, 1953

By S Vianna

Mineralogical information obtained from plant surveys is subject to errors, both due to sampling and experiment. To reduce these errors, and to ensure that information is consistent, a data reconciliation model has been developed for mineralogical data. Its capability includes mass balancing size data, total assays, assays within size-classes and liberation data. Unlike any other mass balance package, this package also allows reconciliation of the complex mineralogical information. For example, particles cannot simply be treated as binary, but consist of combinations of many minerals. Hence the distribution of mineralogical information is multidimensional and the mineralogical distributions are referred to as multiphase. In this paper, the different levels of mass balancing are explained, including how to mass balance liberation data. Furthermore a new technique based on probability theory can be used to infer distributions even when there is insufficient information to perform a mass balance, and this technique is also explained. Results for various stages are given.

Jan 1, 2002

Over the last 15 years the contract mining concept has developed into an integral part of the Australian mining industry. Today it is a $2 billion per annum industry with the potential to continue to grow at a rate of between ten and 20 per cent. Australian contract miners have also exported the concept overseas where growth prospects are unlimited. The industry today is at a cross-road where both contractors and mine owners must consider the current state of the contract mining industry and where it is heading. To look at the present and the future, it is necessary to look back at the history of contract mining and why it has developed. Current industry concerns can then be summarised and the areas that need to be considered to enable the industry to prosper, reviewed. The ultimate goal is to reach solutions with benefits to both the mining companies and the contractors.

Jan 1, 1996

By Croggon R

Passing a direct current through a jointed fine grained soft rock mass auses the movement of water by the process of electric-osmosis. There are other processes such as electrolysis which transport ions that interact with associated ions and can, in turn, be oxidised. This results in the dissolution products being transported towards the cathode electrode. In the cathode region the ferrous hydroxide is oxidised to ferric hydroxide %%ith consequent precipitation. The cracks and joints are current pathways, along which the ferric hydroxide is deposited. This deposition reinforces the joints and increases the shear strength. By adding calcium chloride to the anode, the rate of corrosion is increased with the concomitant increase of deposited ferric hydroxide along the joints. This, in turn, significantly increases the joint shear strength. The process is pervasive in that the current via the water paths travels through the crack and joint systems The result is that not only specific joints are reinforced but the cracks and mtciconnected voids are also reinforced.

Jan 1, 1997