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By Y Li, B Shen, S Zhang

Jointed rock mass is often encountered in rock engineering and its stability has always been a major concern in underground engineering. To analyze the stress characteristics and their variations in jointed rocks, in this study, a new concept of sub-instability stage before rock failure is defined, and a new experimental method is used to investigate interaction between defects and intact rock of the jointed rock mass during the subinstability stage., Firstly, external characteristics of stress and failure mode of the whole jointed rock are investigated systematically by conducting uniaxial compression tests on red sandstone samples with a set of preexisting open flaws of different sizes, and the interactive damage of intact parts and defects in the subinstability stage was further studied. Secondly, rock-like material samples made of bonded plaster blocks were tested and internal data from stress sensor between the strong and weak segments were collected. The transforming processes from independent activity of the individual segment to overall interactive movement of jointed rock before the unstable failure were analysed. The test results indicated that the subinstability stage marked the beginning of interactive failure between the intact rock and defects. In the early subinstability stage, the relatively intact parts bore most of the load in a jointed rock mass, and the defects were damaged firstly which caused high strain around it. The areas of high strain increase rapidly, extending and migrating, causing damage to the intact parts. In the later sub-instability stage, the interaction effect reached its maximum, and a large number of cracks appeared in the intact rock and they propagated and coalesced. Intact parts experienced rapid failure and then the jointed rock failed. The experimental method used in this paper to identify the sub-instability stage could be used to identify failure precursors of jointed rock masses and to develop technology for disaster prevention in rock engineering. CITATION:Zhang, S, Shen, B and Li, Y, 2018. Experimental studies on interactive failure characteristics of jointed rock, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 453–461 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

PAPERS : 1 COMPUTER AIDED DESIGN OF MINE WATER MANAGEMENT - Z KESSERU 2 THE HYDROGEOLOGICAL PROBLEMS OF GROUNDWATER PROTECTION IN MINING REGIONS - V A MIRONENKO 3 WATER MANAGEMENT OF THE MAE MOH PROJECT -òò SIRI CHITCHOB 4 WATER MANAGEMENT AND WATER TREATMENT AT GOLDPN CROSS - M P A WILLIAMS

Jan 1, 1988

AustraliaÆs success as a mineral producer and exporter rests heavily on its technological competence. That competence is based not just on adopting internationally-developed technology but also on ground breaking research conducted at Australian research institutions, many of which have global reputations. A number of forces are now operating to speed the introduction of advanced technology to mining and processing operations around the globe and this will create pressure on the Australian industryÆs ability to retain its competitive edge. Examining the foundations of that national research base and the associated culture of innovation may provide some guide to the dynamics that will be required to maintain technical competitiveness in the future.

Jan 1, 2008

By P Lilly

Blasting is the primary comminution process in most mining operations. This process involves the highly complex and dynamic interaction between two main components. The first is the detonating explosive and the second is the rock mass into which the explosive is loaded. The mechanical properties of the rock material (such as dynamic strength, tensile strength, dynamic modulus and fracture toughness) are important considerations in understanding the blasting process. However, it is the characteristics of the geological defects (joints, foliation planes, bedding planes) within the rock mass that ultimately determine how effectively a blast performs in terms of fragmentation, all else being equal. The defect characteristics include, but are not limited to, their orientation, spacing, and mechanical properties. During the blasting process, some of the geotechnical characteristics of the rock mass are substantially changed. From the blasting outcome point of view, the most notable and important is the change in fragment size distribution that the rock mass undergoes. The pre-blast in situ defect-bounded block size distribution is transformed into the post-blast muckpile fragment size distribution. Consequently, it is fundamental to our understanding of and ability to predict the blasting process that both the blastability of a rock mass and its transformation into the fragment size distribution can be appropriately quantified.

Jan 1, 2001

The Malvern Hills coal project is now in an advanced stage of development with the stripping of overburden from above former underground workings in which a 3 m seam of subbituminous C coal with very low ash and sulphur was previously mined. The main seam dips at 45¦ to the south-east, along with other adjacent potentially recoverable thinner seams, and the strike extent of past coal mining in the Malvern Hills approaches 10 km with most extraction by underground methods. Overburden and interburden is predominantly weak mudstone, with only very minor sandstone, whilst a 1 - 2 m thick veneer of Last Glaciation loess covers the area. The coal product from the present mine site will supply the local industrial market, with production planned to peak at about 20 000 tpa. Settling pond design has been based on several different approaches, including an estimate of likely inflows from the contributing catchment of about 5 ha under predicted storms having a ten year recurrence interval. A pond of about 1000 m2 in area has been constructed with its invert in mudstone bedrock, and soil slopes have been lined with lime-stabilised clayey loess silt incorporating a gravel armour layer. The pond outflow takes place via a 2 m high 1.8 m diameter concrete dewatering tower, with a skimmer arrangement to lower the pond by approximately 500 mm between storm events. The overflow water discharges to the main stream above a natural wetland, which will act as a secondary polishing pond, and this is to be enhanced in conjunction with the neighbouring forestry company. Discharge consents specify turbidity and pH as the controlling criteria, and both will be monitored at the settling pond discharge point as well as at the entry to the main stream. Investigations to date indicate that the pH of water exiting from previous underground workings is in the range 6.8 to 7.2, and that acidic drainage will not be an issue with this mine site. No dispersive clays have been identified in assessing the overburden and batter materials, although erosion during storm events is expected and all drains will ultimately be routed through the main settling pond to ensure adequate control of runoff-generated sediment. Reestablishment of vegetation on cut and fill batters remains a priority, and ongoing monitoring will ensure satisfactory long-term performance of the pond system.

Jan 1, 2003

By Riley S

Many regulatory bodies have, or are considering, guidelines that require rehabilitated mine spoils to be erosionally stable (satisfying quantitative limits) over specified design lifetimes. One of the problems facing the industry is that many of the computer models used for erosion assessment were developed for agricultural applications and are unable to predict the change in the shape of engineered landforms over extended periods of time. In particular, they cannot predict where valleys and gullies will develop in the landforms and how big or deep they will be. Furthermore, many existing models require considerable skill to use. A computer model (SIBERIA) developed by the first author, able to model this valley and gully development over long design lifetimes, and which is directly based on digital terrain maps is discussed here. Proposed rehabilitation strategies for waste rock dumps at Ranger Uranium Mine as assessed with SIBERIA are discussed. New features of SIBERIA of interest to the mining industry include the spatial distribution of erosion, deposition and gully development, and various measures of the quantitative risk of failure. A collaborative project with the Queensland Coal Association, involving the first author, aims to deliver these capabilities to the coal industry in a user-friendly package. The objective is the cost-effective rehabilitation of strip mines. Some preliminary results from this project are presented.

Jan 1, 1994

By Chen J, Sun ZY

The present paper gives the design of a new HGMS for magnetic separation of sulphides. The main characteristics of this HGMS are using iron-cladding saddle-shaped magnetic coil for instead of the ordinary magnet, and combining reciprocal-linear motion with vibration to actuate the separation box, and the magnetic field intensity is high up to 2T as well. For improving the magnet system design, a modified finite element method is used to calculate the distribution of magnetic field intensity of separation space of the magnetic coil, and accordingly the calculation results the magnetic leakage coefficient can be determined easily, thus designers apart from the empirical way. KEYWORDS: HGMS, reciprocal motion and vibration, finte element method, saddle-shaped coil.

Jan 1, 1993

By Mosusu N

Geothermal anomalies of different types occur within distinct geological/structural settings in Papua New Guinea. According to R.F. Herring, geothermal occurrences in Papua New Guinea can be classified into two types, those related to vulcanism (Lihir, Rabaul and other series of islands along the volcanic arc) and those resulting from a regional heat flow probably caused by radiogenic sources, for instance those in the Wau/Bulolo area. The manifestation of this potential source of energy generally coincides with either converging or diverging tectonic plate boundaries. Previous inventories on thermal waters were carried out by vulcanologists from the Rabaul Observatory in the early 1960s. However, these studies rarely included chemical analyses of water and gas emissions and the investigations were carried out in an ad hoc manner, generally as a secondary activity. The most recent investigation on thermal waters was conducted on Lihir Island in connection with the development of the open pit gold mine. These studies included detailed exploratory drilling to a maximum depth of 730 m, and a water chemistry isotopic sampling and analysis programme. The hydrothermal waters were not considered as an energy source but as a hazard during the development stage of the mine. Nevertheless, the geothermal anomaly observed at Lihir includes hot springs emerging along the coastal zones with temperatures that approach 100¦C, steam, and thermal borehole waters with temperatures that exceed 200¦C. Chemical analysis results of thermal fluids from Rabaul, Talasea and other areas in Papua New Guinea generally show high total dissolved solids and low pH. In contrast, recent results from the deepest and hottest thermal source at Lihir shows a neutral pH, a Na-CI-SO4 composition and temperatures above 200¦C. Despite the concentration of chloride being similar to that of sea water, other chemical results and stable hydrogen and oxygen isotopic compositions of thermal fluids imply the source to be mixture of local meteoric water and deep thermal water rather than sea water. Results of geothermal modelling suggests that the total geothermal uptlow is equivalent to 54 MW.

Jan 1, 1997

By D C. S M, J Skudder, R F. Sandenbergh

Metallic sulfide minerals present in most gold ores, Morila gold ore included, often decompose under typical gold leaching conditions. The reactions and their products consume oxygen and sodium cyanide, consequently competing for oxygen and cyanide used in gold dissolution. The resultant effect is to reduce both the kinetics of gold dissolution and overall extraction efficiencies. The present paper discusses results obtained from plant data analysis and laboratory work investigating the problem of higher than expected consumption of sodium cyanide at Morila Mine Gold Plant. Cyanide consumption at the Morila Mine Gold Plant had been consistently running at 46 per cent higher than the expected value without any corresponding increase in gold recovery. In fact, plant data analysis showed an inverse relationship between cyanide consumption and grind, as well as cyanide consumption and gold recovery. Experimental and plant data analysis indicated that better control of the [CN-]/[O2] ratio is necessary for the efficient use of reagents and achievement of higher gold recoveries. Careful control of this ratio at a minimum of eight enabled the reduction of sodium cyanide consumption by 200 g/t, that is, from 650 g/t to 450 g/t. Coupling these experimental conditions with the addition of lead nitrate at 100 g/t improved the overall gold recovery to 93 per cent compared to the average plant recovery of 90.2 per cent over a six-month period. This improvement was also reflected in the leaching kinetics where 70 per cent gold extraction was achieved after four hours, as compared to 59 per cent in the absence of lead nitrate addition. Also of great importance is the fact that the combination of hydrogen peroxide and oxygen gave inferior performance relative to either of the two reagents used separately. This scenario presents an opportunity for excluding hydrogen peroxide, an expensive reagent, and focusing on improving the oxygen addition system to boost dissolved oxygen concentration in the plant.

Jan 1, 2007

By P A Ferenczi

The Proterozoic iron oxide related Au-Cu-Bi (Tenant Creek style') deposits at Tennant Creek can be classified as syntectonic polymetallic hydrothermal replacement type mineralisation. These deposits have characteristics in common with a number of other Proterozoic iron oxide (Cu-U-Au-REE) hosted deposits in regions which include Southeast Missouri, USA; the Kiruna district, Sweden; the Great Bear Magmatic Zone, Canada; the Stuart Shelf, South Australia; and the Wemecke Mountains, Canada. Similarities between these and Tennant Creek style deposits include: 1. Tectonic Setting: Formed at shallow crustal levels (

Jan 1, 1994

I feel a little like the Parson delivering his Sunday Sermon, chastizing his parishioners for not coming to Church. Those who need to hear me are absent.Nevertheless, I hope that if you agree with what I am about to say you will go forth and spread the word.We often hear of the impact mining has on the community. I prefer tonight to deal with the impact some community attitudes have on mining, and I want to point out that the results of these attitudes rebound to the detriment of our society. I want to deal particularly with regulation, taxation, and proflts.In a civilization whose standard of living is essentially dependent on an adequate and reliable supply of cheap metals and fuels, it should be evident to Blind Freddie that mining must be encouraged.I must express concern at the constraints inflicted on the mining industry by our community. We tend to blame Government for our difficulties, but we must recognize that Government acts merely as agent for the community. It is fair to say that in a free society, if Government actions do not reflect the demands of the electorate, then it doesn't stay the Government. It is important though for Government, in framing its policies, to ensure that it is not unduly influenced by the loud voices of minority groups.The people of our nation have every right to demand that our industry meet certain criteria to be allowed to operate. We all wish to live in a healthy and congenial environment, and to have our individual comforts protected. It is essential, however, that the community realizes that its demands on the mining industry are affecting Australia's prosperity.Each new regulation and each new tax or impost has its effect on investment, employment, and national revenue. Restraints result in an increase in costs which in turn raises the minimum value of a mineral deposit which is economically mineable. It results in minerals, which could be mined under more favourable circumstances, remaining in the ground, perhaps lost for ever.

Jan 1, 1978

By Dmitrievskaya TY, Cheremnykh PA, Kuftinova IV, Yaremenko VN

The comprehensive processing of raw materials and the tendency to waste-free production require the combination of various methods of concentrating mineral resources. Magnetic separation, an ecologically clean method of concentration, is one step in the technological cycle of ore processing, and cleaning and classifying of raw materials. Separators with superconducting magnetic systems cooled by liquid helium are the novel equipment for practical concentration. Recently, high-gradient (HGMS) and open-gradient (OGMS) magnetic separators using the effect of superconductivity have appeared. The separators of the first type are expedient in the head-end of the technological cycle, as they are most efficient for processing of particles 100 ¦m and greater in size. In this case the main task is to obtain pure tailings with a minimum amount of the useful component. This method allows the essential reduction in the cost of the subsequent crushing and grinding, because only the magnetic concentrate is directed to further processing. The separators of the VGMS type are used more efficiently in the final stages of the concentration cycle to condition the end product. The present work is devoted to the theoretical and experimental investigation of the motion of weakly magnetic particles in the working chamber of superconducting separators of the open-gradient magnetic separator (OGMS) and HGMS types. The flat OGMS is equipped by a magnetic system with NbTi racetracks cooled by liquid helium. The chamber is divided into zones by partitions parallel to the plane of the magnetic system. It is shown how, depending on the number of the zones and their depths, the extraction function of the OGMS varies and the transition from the OGMS to the HGMS occurs. The particles 2 mm and less in size are considered. The extraction parameter distribution of the particles was measured for a multicomponent weakly magnetic ore. It was experimentally shown that xD2 is the extraction parameter for the particles in the OGMS on condition that (p-po)D /l8/tl/g

Jan 1, 1993

Key incompatible element ratios for metabasalts from the Early Permian Croisilles and Patuki Volcanics, South Island, New Zealand, provide constraints on the tectonic environment in which their precursor ophiolitic protolith formed. Two geochemically distinct metabasalt suites are recognised among both the Croisilles and Patuki rocks. Metabasalts from one suite exhibit the geochemical signatures of depleted tholeiites from oceanic spreading ridges (N-type MORB) or spreading centres in evolved back-arc basins. These N-type tholeiites show high Zr/Nb ratios (Zr/Nb = 37-62) and are depleted in light rare earth elements (LREE)((La/Y)N

Jan 1, 1987

By N Vagias, R Shaw, M Coghill, W Easman

Rio Tinto Technology and the Rio Tinto Foundation for a Sustainable Minerals Industry have funded the development of a practical floating module that can reduce water losses through evaporation from water dams at mining and mineral processing facilities by about 75 per cent. The modules, which are also suitable for use by farmers and communities, were designed for easy deployment, to allow the water to æbreatheÆ, harvest rainfall and resist wind speeds of more than 100 km/h. A large-scale demonstration trial will be conducted at the Northparkes Mine, located near Parkes (New South Wales, Australia). The objective of the trial is to demonstrate to Rio Tinto business units, community, farming and government groups the moduleÆs operating costs and water saving potential.

Jan 1, 2006

By Cecala AB

For 20 years the US Bureau of Mines has been researching strategies for improving the physical, social, and psychological work environment of the miner. The products of this program have shown that a consistent link exists between safety and productivity, and the key to this link is the use of effective human factors and management practices. There are specific research findings from the research projects of the Bureau on ergonomic design of mining equipment, redesign of tasks (especially materials handling) to minimize back injuries, human resource management techniques for increasing safety and productivity, and improved shift rotation schedules. Current research is continuing these themes with new applications to high technology mining systems, including computer assisted extraction devices and mine monitoring.

Jan 1, 1991

By Seib W

In cut-and-break rock excavation use is made of the fact that breaking rock in tension towards a free face requires a specific energy of excavation which is small in comparison with that required for rock excavation using conventional tools operating by a process of indentation of the rock.The process of cut-and-break excavation comprises firstly a cutting step in which a groove is cut into the rock surface, followed by a breaking phase in which a tool is inserted into the cut in order to break the rock adjacent to the cut.

Jan 1, 1992

By Wright D. J

Successful heap leaching depends on three major factors: 1. Chemical conditions appropriate for the dissolution of the valuable metal; 2. Contact between the leach solution and the valuable metal particles; and 3. Movement of the leach solution through, and out of, the heap. Given that appropriate chemical conditions can be provided, and the individual particles have sufficient permeability to allow solute/solvent contact, the problem of getting the solution to and from the particles remains. Non-uniform percolation of solution throughout the heap, caused by the presence of fines, is a common problem which occurs, to some extent, with all heap leachable ore. The conventional solution to this problem is agglomeration, which involves the attachment of fine particles to larger particles, effectively modifying the size distribution by preventing the fine particles from acting on their own. While agglomeration must be considered as an extremely effective technique with virtually no limit to its application from a technical point of view, its application is limited by economic considerations. A new technique has been developed which is not only a low cost alternative to agglomeration, but also has the potential for enabling the application of low cost heap and vat leach techniques to a significantly wider range of ores than current practice would suggest. The new technique, known as Electrokinetic Leaching, utilises electro-osmotic flow to enhance percolation through the heap. This paper describes and presents results of the laboratory testing, pilot heap operation and commercial application of Electrokinetic Leaching of a low grade gold ore and a tailings deposit. Comparative cost analyses between conventional and the alternative processing techniques are presented.

Jan 1, 1994

By B Morey, J Gordon, P Mackenzie

Mount Tom Price Mine is peerless amongst Rio Tinto iron ore resources around the world. It has provided Hamersley Iron with premium quality, high lump yield haematite ore over the last four decades. The Brockman type bedded ore, containing bands of haematite and shale of varying thicknesses has been traditionally bulk mined to either high-grade or low-grade based on alumina cut-off grades. As open pit mining has progressed deeper into the orebody approaching the keels of the megastructure, increased structural complexity, chemical and physical variations in the ore, unfavourable ore presentation and reduced blending options have become an issue for grade control and may have serious impacts on product stockpiles. The grade blocks and boundaries must be accurately defined according to geological contacts and where identified, selective mining may be applied. Therefore in-pit geological mapping is the definite and ultimate guide to achieve target grades and grade predictions. Under this scenario, it is absolutely vital that the mine geology team ensures this geological knowledge is passed onto the related departments including mining crews as well as to the short- and long-term planners.

Jan 1, 2002

By Neill T. J, Howarth D. F, Malcolm J. McPhersqn

For many years Isa Mine has seen the need for a continuous mining machine which will economically cut hard rock. Tunnel borers are unsuitable due to the size and inflexibility of the machine and the shape of excavation mined. The design of roadheader type machines will not permit the use of the necessary cutting technology. in 1983 a joint project was undertaken by The Robbins Company and Mount Isa Mines Limited to develop and to trial a machine suitable for cutting hard rock in an operating mine. The project was based on the proven technology of raiseboring applied to horizontal development. The Mobile Miner was fabricated and trialled in a disused quarry in the U.S.A. during early 1984. Following these trials, the machine was transported to Mount Isa and commenced mining in September that year. The initial duty was to continue the development of a decline commenced by conventional mining for a conveyor system to serve the deeper southern areas of the 1100 copper orebody. This system will permit direct tipping of copper ore to a new crusher complex and conveying of the - crushed ore approximately 2 kilometres to the central hoisting shaft facilities. The Robbins Mobile Miner MM120-3001 uses a vertical rotating cutting wheel mounted on a horizontal swinging boom to excavate a nominally rectangular shaped heading. The cuttings are collected on an apron and conveyed back through the machine. The resulting excavation is smooth-walled with no blasting damage to the surrounding rock. This provides a safer working environment than does conventional drill and blast development mining. Ground support requirements are considerably reduced.

Jan 1, 1986

The earth is a planet limited in size and limited in total resources. For the forseeable future, it is the only available habitat for mankind. Therefore, it follows that the more we know about our planet the better we can utilize its space and its resources for our well-being now and in the future. But, to accomplish this, we need reliable basic information. Geosciences provide such information. Recently, Dr. M. King Hubbert took note of the important effect of the geosciences on society, on how we think, and how we live. In the first century of modern geology, 1780- 1880, the influence of geology was primarily on how we think, i.e. changing our concept of the earth from one with a short catastrophic history to one that developed gradually over enormous spans of time. In the second century, 1880-1980, the emphasis was on how we live, on expanding the knowledge base so that we could more easily find and utilize the earth's resources. Now, in the third century, i.e. from 1980 towards the year 2000 and beyond, we should concentrate on both how we think and how we live; i.e. how we can better estimate potential global' resources and how we can manage these resources for maximum benefit to mankind. Like other sciences, the geosciences build upon what has already been done. Progress is achieved by using the thoughts, measurements, and observations of past workers, adding to these the insights from new experiments and from new concepts. Geology has its own methodology and approaches; but more than most sciences, it calls also upon the tools of physics, chemistry, mathematics, engineering, and biology to help solve its problems. Today's increasing population, increasing industrialization, and increasing complexity of modern society demand more detailed geoscience information so as to better use the land, reduce geological hazards, provide an inventory of resources, facilitate waste disposal, and prepare for long-term effects such as changes in climate and sea level.

Jan 1, 1986