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The problems encountered with the introduction and use of Isanol underground are described. Significant direct as well as indirect savings have resulted from the use of Isanol. Field studies have shown that the concentration of common gases released during detonation is considerably lower than with conventional nitro-compound type of explosives.

Jan 1, 1977

It is a great privilege to be invited to give this address at this centenary conference. A centenary is a time for recollection, for celebration and for looking ahead. The AusIMM has much to celebrate and many things to recall. I hope in this address to make some useful comments about Australia's future (and mindful of but not forgetting New Zealand), looking ahead for 25 years or so, and the mining industry's role in that future.

Jan 1, 1993

This paper examines the concepts of risk analysis and uncertainty in open pit mine design. It describes the relationship between risk analysis and uncertainty, describes methods that can be used to quantify uncertainty, and suggests ways of reducing the geological and geotechnical uncertainties that are inherent in open pit mining.

Jan 1, 1994

By Dight P. M, Dugan K. J

Design approaches for the artificial support of open pit walls have been reviewed and the main factors affecting support performance have been identified. An example of passive support in a potentially unstable pit wall has been used to demonstrate the importance of slope displacement as part of the support design process.

Jan 1, 1989

In his introductory remarks Mr. MacKellar referred to three types of development which may be considered to compete with mining for land use. 1. Total Development - in which he cited urban development, and intensive agriculture. 2. Partial development - in which he cited pastoral, and in this category would come National Parks. 3. Non development - in which category would fall the primitive or wilderness areas.

Jan 1, 1971

By Dickin FJ

Advances in the development and application of in situ imaging of mineral processing operations using electrical tomography techniques are reviewed and illustrated with case studies relating to pneumatic conveying, mixing and centrifugal separation processes. The potential for applying these methods to full three-dimensional visualisation of the dynamic behaviour of flow in pipelines and separators, and the resulting consequences for process-modelling strategies, are discussed.

Jan 1, 1993

By P Aspinall

Safe work Australia (SWA) has a number of proposed amendments to existing Workplace Exposure Standard (WES) values that may dramatically change how mining workplaces using personal gas monitoring instruments will operate. In consultation with leading gas monitor manufacturers and distributors, an assessment of common Australian alarm settings values and analysis of potential frequency of increased alarm likelihoods has been conducted. This assessment explores the relationships between current monitoring practices, using instruments as health and not just safety tools and identify what will be needed to minimise worker ‘alarm fatigue’ and for common tasks to continue safely. This paper provides the necessary information to aid industry and hygienists to be ‘future ready’ given the likely impact that order of magnitude reductions in time weighted average (TWA) values for NO2, SO2, H2S and other common gases will have on current working practices. Reductions to gas alarm values will provide significant challenges to existing work methods and will require, practical application of the pending future values. Improvements and awareness of instrument capabilities by safety and hygiene professionals will better utilise gas monitors real-time data monitoring capacity and no longer be just ‘safe or not-safe’ instruments. The presentation seeks to promote the practical steps required in setting alarms based on risk consequence and likelihood, increase general awareness of the tools and data available in modern instruments and will enable industry professionals to better manage the challenges of any potential future changes.

Apr 16, 2024

By P W. Cleary, M D. Sinnott

Cross-belt cutters are commonly used for sampling coal. They are generally cheaper than falling-stream cutters, particularly when a cutter must be retrofitted. The major mechanisms thought most likely to lead to sample bias are being investigated by discrete element modelling (DEM) in a project funded through the Australian Coal Association Research Program. This paper describes a benchmark run and the current direction of research.

Jan 1, 2008

The paper describes the geotechnical as- pects of design and construction of two 12 m diameter concrete lined tunnels from the start of design to completion of construction. Prob- lems occurred due to delay in supply of essen- tial rock support materials from overseas and alternative methods using locally available materials were developed. Several major rock- falls and rock movements occurred and remedial measures are outlined.

Jan 1, 1981

By Coates J. R, Firth I. C

The Imperial Smelting Furnace at Cockle Creek, NSW, was constructed in 1961 and is the oldest facility using the Imperial Smelting process in operation. In recent years there have been significant improvements in many areas of the operation, including production, safety, hygiene and environmental performance. Steps taken to achieve these improvements are described. Plans to secure a profitable future while meeting environmental requirements are outlined.

Jan 1, 1993

A small-charge rock excavation method based upon the Penetrating Cone Fracture (PCF) technique has been demonstrated to be capable of excavating the hardest of rocks. The PCF technique involves drilling shallow holes in the rock which are then pressurised at the bottom by a propellant charge device. A controlled fracture is initiated at the hole bottom comer and propagates in such a manner as to excavate the rock at an energy efficiency three to five times better than explosives. Due to the low flyrock velocities and airblast pressures realised with PCF breakage, the method may be used in close proximity to equipment and personnel and is thus ideally suited for integration into continuous hard rock excavation systems. Over the past 18 months full-scale testing of the PCF method has been carried out in mines in the US and Australia. This testing has utilised a 76 mm diameter gas injector for hole pressurisation and employed propellant charges ranging from 80 to 320 gm. In addition to extensive data on rock excavation performance, data on ground motion, dust, carbon monoxide and air blast have been obtained. These data indicate that none of the parameters associated with PCF breakage are detrimental to the development of PCF-based, continuous-excavation machines. Machines employing the PCF method may range from simple single-boom machines for secondary breakage and small precision-blasting jobs to integrated systems with several booms, continuous mucking capabilities and ground-support equipment for drifting and tunnelling.

Jan 1, 1993

By Jones M

The concept of precise, accurate timing with Electronic Delay Detonators (EDDs) was first seriously addressed in the mid-1980s and much was made of the cheapness and profusion of digital watches in terms of the likelihood of EDDs also being cheap and easy to produce. Ten years later, with every major explosives company and many electronics groups having instituted projects to capitalise on the promise of these devices, production devices are still to come into general use. In South Africa, Expert Explosives units have been used in most applications during proving trials and more recently for production blasting in underground ring stoping and open cast coal. The outcome has been valuable learning both as to the benefits and technical requirements for electronic delay blasting, and especially, safety aspects. Examples are shown of production blasts which utilised the power of EDDs. It is evident that it is not delay accuracy alone which determines the value of these systems, but the whole robustness, flexibility and ease of delay allocation when harnessing blast engineering knowledge. Muckpile movement and shape, fragmentation and vibration frequencies have shown to be greatly influenced by designs which can be implemented no other way. The flexibility of a system and the power of the software controlling it are crucial in capitalising on blasting potential, which lies in integrating control of blast timing with other developing electronic Technologies.

Jan 1, 1995

By Khosia NK, Ravishankar SA, Sankar TAP

Alumina reduction in Rajhara iron ore slimes essentially involves separation of hematite from gibbsite in relatively coarser fraction and from kaolinite in the finer fraction. Selective dispersion flocculation studies on synthetic mixtures clearly indicated that while it was possible to achieve almost perfect separation of hematite from kaolinite using starch and PAMX (modified polyacrylamide containing hydroxamate functional groups) flocculants, no selectivity was observed in iron oxide-alumina system. A schematic flowsheet suggested on the basis of this work for the beneficiation of Indian ore slimes thus consists of classification in a hydrocyclone, followed by selective dispersion of coarse fraction (underflow) and selective flocculation of the overflow fraction. Starting with a feed assaying 46 per cent Fe and 11.6 per cent A1203, a concentrate assaying 60 per cent Fe and 4.7 per cent A1203 could be produced at an overall iron recovery of 60 per cent using conventional Reagents.

Jan 1, 1993

Despite improving technology, better training and the use of modern monitoring and communication systems there is a disproportionate rate of diameter occurrences in the mining industry. The use of appropriate plans and a practical approach and managing risk can reduce the number of occurrences and ensure better control of emerging situations when they do Occur.

Jan 1, 1998

The procedure used for Truck Maintenance is described systematically in this paper. Emphasis is given to manpower required, work facilities, daily maintenance and oil sampling procedure. Scheduled Preventative Maintenance Service, Electrical Service, Component Change, Truck Overhaul and Outside Contractors are also discussed. The system used, achieves the required results with an average haul truck availability in 1981 of 87.9 per cent. INTRODUCTION Situated on the Island of Bougainville, in Papua New Guinea, the Bougainville Copper mine nestles in a valley near the crest of the Crown Prince Range, between 600 m and 980 m above sea level. The mine is serviced by two towns, Arawa - an open town on the Coast and Panguna at the Mine Site. Currently Bougainville Copper operates an open pit mine removing an average of 198 000 dry metric tonnes of material per day (115 000 tonnes ore and 83 000 tonnes of waste) with a fleet of electric shovels and 154 tonne electric haul trucks.

Jan 1, 1982

By Lloyd F, Bayley F. J

The new South Mine in the Western Deep Levels complex is destined to become an ultra deep project extending to depths of 4 200 m below surface and where rock temperatures are likely to exceed 65 ¦C. Initial estimates put refrigeration requirements at 133 000 kWR. A surface refrigeration plant with an initial capacity of 42 000 kWR has been commissioned and will be used for mining the upper levels.

Jan 1, 1988

By Chitombo G. P, Thompson A. G

Excavation engineering involves three key design processes; excavation design, blast design and reinforcement design. An excavation engineering methodology is proposed in an attempt to promote integration and simultaneous consideration of these three design processes. This methodology requires research and development of, inter alia, a universal rock mass classification system and a universal data display system. Simple examples are used to explain and illustrate the concepts central to these components in the three design processes.

Jan 1, 1995

Pipe Jacking has been a recognised method of tunnelling in the U.K. since the early 1950's, although I understand that pipes were pushed blind by the soldiers in the first World War from trenches on the Allied side to, or adjacent to, trenches on the German side, thus allowing explosives to be used with a certain element of surprise! 'However, on its more conventional to the U.K. in the 1950's, Pipe Jacking made considerable inroads into the tunnelling market place as an alternative to timber supported headings. This success was, unfortunately, fairly short lived because, owing to its simple method of operation, contractors paid insufficient detail to the engineering (or surveying) aspects and as such the system soon had a bad reputation for unreliability and lack of accuracy. Due to these failings, the market was not exploited and, therefore, there was a lack of investment by contractors, pipe manufacturers and also by any client, or research organisation, which is client associated. The effect of this meant that the system stagnated for a number of years and was used generally only for short crossing work (i.e. railways, canals and motorways), and then only in good homogeneous ground. Albeit, a limited number of full scale sewage disposal contracts were carried out, but with the lack of knowledge and experience of the clients, contractors and suppliers, (particularly the pipe suppliers), no reasonable success, either physical or financial, was achieved on any such contract.

Jan 1, 1987

By Taylor L. M

Accurate computer prediction of the muck pile produced by a conventional blast requires modeling of the physics that occurs during the rock motion phase of a blast. The ability to predict the motion and the subsequent muck pile can have a significant economic impact on the mining industry. Some of the computer programs previously used to predict rock motion employed polygonal elements with comers and sides to model the rock (Cundall, 1971; Walton, 1982; Taylor, 1983). This approach allows the elements to bulk because of the corners and the aspect ratio. However, tracking the many interactions of the comers and sides of the elements is a computationally intensive process. Several other rock motion computer programs were developed that employed spherical elements, (Schamaun, 1984; Gorham-Bergeron et al, 1987) but they lacked correct bulking mechanisms or could not be vectorized for efficient execution on vector processing machines. A new spherical element code called DMC (Distinct Motion Code) (Taylor and Preece, 1989a, 1989b) has been developed this past year. DMC was designed and written to take advantage of super-computer vector processing capabilities. The efficiency has also been increased through the use of spherical elements, explicit time integration and a new contact search algorithm. When spherical elements were chosen for efficiency, some physically correct mechanisms for capturing the bulking behavior of the rock mass also had to he developed. This paper will treat several mechanisms that were developed to allow spherical elements to exhibit correct hulking behavior.

Jan 1, 1990

By Torres F, Cerda I, Gimenez P, Gonzalez G, Castelli L

Slurry density measurement, specially in cyclone feed streams, is fundamental to grinding circuit control. With the purpose of increasing the availability of such a measurement, the design of a soft-sensor in an actual grinding plant is addressed in this paper. The system is designed to substitute the momentary unavailability of the real density sensor, either because it has failed or because it has been removed for any other reason. The ARMAX model structure is determined using the stepwise regression method. Starting with a list of the candidate variables, the method selects, one by one, and in a systematic manner the variables which best model the measurement to be replaced, choosing them from the set of presumably correlated candidate variables. In this paper not only the single measurements are included in the list of candidates, but also combinations of such measurements having physical significance. A phenomenological model has been built with the purpose of determining these combinations. It turned out that in most of the cases the components of combined measurements having physical significance were selected by the stepwise regression method, instead of the single measurements. Actual grinding plant data is used to determine the model structure, to estimate the model parameters and to test the predictive capability of the developed soft-sensors. Good results are shown to be obtained during periods of up to 30 hours of the density soft-sensor operation.

Jan 1, 1995