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By C Smith, D Lilly

The Lafarge Marblehead Plant in Marblehead, Ohio, USA produces 4.2 million tonnes of sized aggregate yearly. In 1997, a program was instituted to maximise primary crusher productivity through the optimisation of blasting variables and procedures. A proprietary blasting shot report database and the Lafarge production database was statistically analysed to provide guidance in the program. Blasting powder factor (kg/m3) was the main control variable utilised to increase crusher throughput. In 2005, the program was refined to increase the production of certain high margin aggregate sizes and the reduction of fines. The principal blasting component affecting the percentage of high margin size production appears to be pattern area (burden and spacing area). This can be coupled with powder factor to optimise the production rate of high margin aggregate sizes. The size optimisation program incorporates the blasting shot report database, Lafarge production database, statistical analysis and aggregate sampling. A preliminary indication is that the production of high margin sizes (12.7 mm X 4.8 mm, 24.4 mm X 12.7 mm, and 50 mm X 25.4 mm) has been increased seven to 12 per cent utilising these techniques. As an added benefit, blasting costs have been reduced linearly as burden û spacing pattern areas have increased and powder factors have decreased. The program is ongoing and will investigate other blasting procedures and variables including electronic blasting caps to further increase the production of high margin products. The statistical methods involved in the analysis are described in this article for use in other mines and situations. The methods described can be used to optimise crusher throughput, digging rates and product size.

Jan 1, 2007

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

Following GyÆs earlier proposals for the use of StudentÆs t-test, a simplified, effective method and philosophy are proposed to test for maximum tolerable bias in data sets as well as in sampling devices. The philosophy of testing is particularly emphasised to derive important practical implications in terms of decision-making and risk control. Conclusions are offered which should equally matter to manufacturers and users of sampling equipment.

Jan 1, 2005

By Giannini L. M

A method using dynamic programming for solving the optimum pit limit problem was presented in an earlier paper. A recent issue of this journal contained some contributed discussion on the implementation of this technique. In this paper we provide some additional ideas and possible options one can incorporate into the method. In particular, an efficient procedure for obtaining further optimum pit outlines on extensions of the original block model is described.

Jan 1, 1987

By Agrawal R. D, Kapoor M. L

Activity of FeO in the ternary system MgO-FeO-CaO in contact with metallic iron has been measured at 1000 K employing the cell.PtIFe, (Mg, Fe, Ca)OIZr02 - CaOIFe, FeOlPt. Measured data are used to study the phase stability relations in the system MgO-FeO-CaO and an isothermal section at 1000 K through this system is drawn.

Jan 1, 1987

The exploration industry generally has a low opinion of the quality of the service supplied to it by government departments. In particular, the academic research-related emphasis of the Bureau of Mineral Resources (BMR) and the relatively low level of explora- tion assistance offered by several Mines Departments are of concern. In a number of areas of geoscience research, the industry perceives a mixup of priorities and a lack of understanding on the part of governments as to its needs. While government's sights are, and should be, set on the future needs of the community at large, the industry doubts that government budget allocations to the BMR and Mines Departments are either large enough or being cost-effectively spent. This is certainly the case for such areas as exploration assist- ance, provision of basic exploration data, and applied geoscientific research. On balance, the exploration industry's perceptions are misguided in a number of respects because of a lack of communication with government. However, this reinforces the need for changes in the manner in which govern- ment departments communicate with industry and, in particular, the criteria upon which research priorities are based. At a time of contracting oil and mineral exploration expenditure, and near-record levels of geoscientist unemployment, the government's role is critical and should be open to question.

Jan 1, 1986

The main iron ore deposits of Western Australia fall into three very different geological classes, which are, in order of importance: hematite enrichment ore, pisolitic limonite ore, and sedimentary ore. These are presently (1973) being mined in the approximate proportions 20 : 2 : 1, while the equivalent proportions for reserves are, very approximately, 200 : 70 : 1. Two minor categories which mar- ginally qualify as ore are detrital material variously referred to as scree ore or canga, and potentially beneficiable iron formation. These two latter types are dealt with very briefly, and the three main categories are dis- cussed in order of economic significance. Hematite enrichment ore results from the selective replacement of a pre-existing host rock by hematite. Almost without exception, this host is cherty banded iron formation (BIF); but certain exceptions have great genetic inter- est. Ore bodies of this kind occur both in the Archaean BIFs of the Pilbara and Yilgarn Blocks and in the Proterozoic BIFs of'the Hamersley Basin. It follows from their virtual restriction to a single kind of sedimentary host that there is strong stratigraphic control over the shape of ore bodies: these may be almost flat, of dyke-like form, or of complex configuration, according to the pre-enrichment structure of the host bed. This structure was an important control over the position in which ore formed:

Jan 1, 1973

The Department of Conservation (DOC) manages public conservation land throughout New Zealand in terms of section 6 of the Conservation Act 1987. In brief, this requires DOC to manage the natural and historic resources of the land; promote the benefits of conservation to present and future generations; provide information about conservation; to foster recreation on the land; and allow for its use for tourism.   Locally the department's Tauranga Area Office manages approximately 60 000 hectares of Conservation Park (known as the Kaimai-Mamaku Forest Park) which includes early gold mining relics and former bush tramways associated with the logging and the mining industries. The Department has recently developed the Kaimai Heritage Plan which seeks to restore some of the relics and encourage involvement by the local communities in the restoration and interpretation of their history in the hills. It provides a unique opportunity for the Department to help bring alive for New Zealanders an important, and often overlooked, part of our history as a nation in a stunning natural setting.   The purpose of this presentation is to: +        display the endeavour and ingenuity of the early miners and loggers, the relics of those industries and the dramatic environment in which they worked; +        identify the linkages between those early industries and gold mining today; and +        promote a co-operative approach to heritage and recreation management involving all facets of the community.

Jan 1, 2006

By S F. Cox

The development of low displacement, moderate to high-angle reverse faults during the formation of the Argo gold deposit within a tholeiitic gabbro host-rock involved a four stage evolution of deformation and associated hydrothermal alteration. Fault zone evolution and Au mineralisation were associated with high fluid flux, fault-valve behaviour in a severely misoriented fault zone. The far-field maximum principal stress was approximately east-west and horizontal, and the far-field minimum principal stress was subvertical. The fault system developed at approximately 400¦C in a transitional brittle-ductile regime. Initial Stage 1 deformation involved ductile shear and the development of potassic (biotite-rich) alteration assemblages and associated reaction-weakening in shear zones; minor quartz extension veins were formed. Stage 2 is marked by the onset of predominantly brittle shear failure, the widespread development ofmatrix-supported breccias in fault zones and a change to sodic (albite-carbonate-quartz) alteration styles. Extension veins have limited development. Stage 3 is also dominated by brittle shear failure and characterised by a change to quartz-carbonate assemblages in fault-fill veins and breccias. However, large arrays of extension veins are also well-developed adjacent to faults. In Stage 4, widespread subhorizontal quartz-carbonate-biotite extension veins were developed, but shear failure was limited. This is an ABSTRACT only. A full-length paper was not prepared for this presentation.

Jan 1, 2008

AustraliaÆs current interest in renewable energy is based on a desire to reduce the countryÆs greenhouse gas emissions. Wood from sustainable sources offers a unique opportunity to combine greenhouse gas benefits with other significant environmental and social benefits, including salinity mitigation, carbon sequestration, soil replenishment and rural industry. The challenge is to make renewable energy from wood in a cost competitive manner, so that this broad range of benefits may be best realised. Bioenergy and carbon products are of great interest as new, commercial forestry products that can drive large-scale environmental tree planting:In Western Australia, Enecon has worked with Western Power Corporation to build the first full-scale plant for integrated processing of mallee eucalypts, to produce activated carbon, renewable power and eucalyptus oil. It is intended that this plant is the first of a number of such plants to help catalyse environmental tree planting in Western Australia. New technologies being developed overseas may provide competitive bioenergy in areas where traditional markets for wood do not exist. For example, pyrolysis converts wood into a bio-oil that may be transported to remote sites for power generation in gas turbines. Pyrolysis also produces wood char. Pyrolysis and wood-to-ethanol technologies, coupled with short rotation coppicing trees, offer the long-term prospect of large-scale production of renewable fuels around the country.

Jan 1, 2006

ALTHOUGH the mineral Stannite (Cu2S, FeS, SnS2 , also known as "bell 'metal" ore, tin pyrites, etc.) is found in various parts of the world, in only three iocalities has development proved it to exist in sufficient quantity to warrant the erection of treatment plants. Two of those mines are in New South Wales and one is an Tasmania. The writer will deal with the latter-the Conah mine, Zeehan, Tasmania, it being the most important and extensive occurrence so far worked. The Conah mine was first worked by a Tasmanian company for silver-Iead, and was fairly remunerative until the zone of secondary enrichment was passed through, when the lodes became too poor for further exploitation. During the time that the line was thus operated the stannite lode was discovered. It occurs in a graphitic slate, which, in common with the slates and spilites of the Zeehan field, is probably underlain by the stanniferous granite which outcrops two miles to the west. The Conah stannite lode is older than the galena lodes of the district, being faulted by one of the latter. Near the surface the lode was very rich.Shipments were sent out assaying 150 oz. of silver per ton, 20% copper, and 18% tin. An .apparently homogeneous sample of stannite, analyzed by the writer for the Tasmanian Geological survey, gave the following results:

Jan 1, 1915

By Bragg R, McMahon B, Lenton R

In 1992 environmental audits were carried out at seven coal mines operated by Oakbridge Limited in the Hunter Valley and Lithgow areas of NSW. The audit reports recommended a course of action designed to improve the environmental management system already in operation at the mines. This program started with training in environmental awareness for the Board of Directors, and the development and authorisation of an environmental policy. On-going programs at each mine were expanded to include environmental awareness training for all 2000 employees at the mines, and the development of a 20-module environmental training program which included air, water, soil and noise management, oil and chemical handling, sampling and monitoring, rehabilitation techniques and many more. Environmental incident reporting was introduced, and a system of reporting from the coal face through individual mine site environmental committees, to a Corporate Environmental Committee and up to the Board Environmental Committee became an effective part of a due diligence program. The Board resolved to undertake external independent environmental audits every two years, with internal reviews in the alternate years. An Environmental Management Group was formed, consisting of four internal environmental personnel and Oakbridge's appointed environmental consultant, to effectively resolve many of the environmental issues facing the Group. This program is continuing to evolve as an industry leader in environmental management Practice.

Jan 1, 1995

By Sanders GJ

Coals from the Southern Coalfield of New South Wales treated in the Port Kembla coal preparation plants of Australian Iron and Steel Pty Ltd differ substantially in their characteristics. Knowledge of, performance not only enables comparison and promotes better control, but also provides the means for predicting results. Evaluation of performance of cleaning equipment has been made in terms of probable error (Ep.) Results for Baum jigs, a Chance cone, heavy medium cyclones and water washing cyclones are examined. The efficiency factors derived from the probable error are applied to the float and sink analysis, mathematically simulating operating conditions. This method is applied to the Balgownie seam. The Balgownie seam lies between the Bulli and Wongawilli seams in the Coal measures of the South Coast and mining on a large scale began recently in the Bulli area. It is known locally as the Four Foot seam and exhibits er difficult washability characteristics, due to a comparatively high middlings content. These properties and the tively high inherent ash make careful selection of cleaning equipment essential for optimum recovery. The prediction technique is used to determine the possible results when this coal is cleaned in the Port Kembla plants. Predicted values are compared with results from full scale trial washings demonstrating the validity and accuracy of the technique. Applications of result forecasting are listed.

Jan 1, 1970

By Oliveira JF

Thiourea is an alternative reagent for cyanide in gold leaching. The recovery of gold from acidic thiourea solutions by adsorption on activated carbon is based on methods similar to those applied for the extracting of gold from cyanide solutions, but the mechanism involved in the process is not completely understood. In the present work, studies were carried out to evaluate the adsorption of gold onto activated carbon. Experimental data showed good agreement with both the Freundlich and Langmuir isotherms. The adsorption of gold from acidic thiourea solutions proved to be an endothermic process, while the adsorption from cyanide is known to be exothermic. The isosteric heat of adsorption of -11.3 kcal/mol in the early stages of the adsorption is an indication of a process involving chemisorption. The effect of temperature was studied between 15¦C and 55¦C. An activation energy of 3.5 kcal/mol was determined by the Arrhenius plot, which indicates that the controlling step in the kinetics of adsorption is the diffusion onto the porous structure of the activated carbon.

Jan 1, 1993

Your Worship the Mayor, Ron McCullough; the Honourable Tony McGrady M.L.A., Minister for Minerals & Energy; distinguished guests, ladies and gentlemen.It's both a pleasure and a privilege to have been invited by the North West Queensland branch of the AusIMM to speak at a forum in Mount Isa to discuss the potential, and more importantly, the development of the great North West. I spent 25 years of my life proudly living and working in this part of the world, marvelling at its riches, exploring its potential, assisting in its development and responding to its challenges.As President of the North West Queensland branch of the AusIMM in the early 1970's I can clearly recall helping to organize a major symposium extolling the geological potential of the region, revealing the extensions of the Mount Isa copper orebody at depth and describing the potential of the then untapped Hilton Mine. Our optimism in the North West so obviously reflected two decades ago remains today.

Jan 1, 1993

By Tapponnier P

In North Vietnam, large ductile shear zones are observed along the Red river fault and the Dienbien fault. Left-lateral sense of the Red river shear zone is related to the direction of shortening E-W. NE dipping foliation planes is subvertical. Stretching lineation is subhorizontal ( 25¦). Left-lateral slip observed in the Oligocene Yansun granites demonstrates the major tectonic phase in Neogene, The stress field established from microfaults observed in triassic limestones, Oligocene granites and Neogene Conglomerates. Measurements of striations on fault mirors are used for calculating the stress tensor and for separating tectonic phases. Two tectonic phases in tertiary are separated : first tectonic phase related to the compressive direction E-W corresponds to the major tectonic phase represented by NW left-lateral shear zone. Second phase having the compressive direction N-S associated with the right-lateral movement of the Red-river fault zone opening of the Eastern sea and the Red-river and the Red-river delta is associated with the left-lateral movement along the Red-river.

Jan 1, 1990

The economic future of the Palmer Goldfield lies with both the gold mining and the tourist industries. An equitable solution to the competition between the two involves putting a dollar value on the historical evidence there for our Australian heritage.On 23 October 1986 the Queensland Government gazetted the Palmer River Reserves R16 of 16 200 hectares, in recognition of the competing land uses emerging in the region. The intention is that historically significant gold mining sites and relics will be preserved in situ with provision for continued gold exploration and mining.This paper explores and explains the administrative process of achieving a set of Management Guidelines for Rl6 within the Queensland political milieu. The result of that process is the achievement of some of the highest preservation standards in Australia, prohibiting surface disturbance of defined Category 1 sites, and no mining proposal has yet been refused approval.The Palmer Goldfield R16 experience is a major step in achieving a co-ordinated approach to both current mining and preservation of Queensland's mining heritage.

Jan 1, 1990

By Bailey H. W

Power supply for remote mining developments is compared with supply to the general public with the conclusion that the private power plant operator has many opportunities to minimise his costs which are not open to public utilities. The main features of diesel, gas turbine and steam power plant and the limitation upon their application which may be imposed by the fuels available and the local conditions at remote sites are outlined. Reference is made to the value of joint examination by the mining engineer, metallurgist and power engineer to decide how to make best overall use of capital, labour and energy in co-ordinating the design of power and process plant and in setting no more than adequate standards of reliability and efficiency. Fluctuations in world markets make it difficult to plan mining operations to a firm time base. Suggestions are made to minimise the financial risk in forward expenditure upon power plant which in large sizes due to longer construction time may have to be ordered before a final decision is taken upon the mining development it is to serve.

Jan 1, 1973

By Lai KF

The Hellyer orebody is a fine grained, massive sulphide Pb-Zn-Ag- Cu-Au deposit located in western Tasmania. Initial testwork showed that the orebody would be difficult but not impossible to treat by conven- tional flotation. A staged programme-of work was commenced to demon- strate that marketable concentrates could be produced with satisfactory recoveries. Following laboratory testing of drill core to define two flowsheets, bulk samples of Hellyer totalling 20,000 tonnes were trialled at 6 tph in the Cleveland concentrator over six months. The high through- put and extended duration of the trials ensured maximum confidence in the results and that scale-up to subsequent plants would be with a mini- mum of risk. The milling trials were successful and the Cleveland concentrator was expanded in early 1987 to treat 250,000 tpa of Hellyer ore to produce 85,000 tpa of bulk concentrates. Late in 1987 construction commenced on a 1 mtpa concentrator at Hellyer to produce separate copper/silver, lead, zinc and bulk concentrates.

Jan 1, 1988

This paper looks at the problems associated with surface settlements and other subsidence effects from the underground extraction of coal in relation to consent applications under the Resource Management Act. The main features of subsidence are examined with respect to identifying the adverse effects as defined under the RMA. Particular attention is paid to sites where little or no data is available as in the case of greenfield sites or at mines where new or different mining methods are being introduced. In these situations it is not possible to make accurate predictions of settlements or strains and therefore other factors need to be considered. The long term effects which might occur post mining are examined in relation to mitigation and management options.

Jan 1, 2003