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By M I. Jeffrey, J A. Rumbal, D M. Hewitt

Ion chromatography utilising an anion exchange column and UV detection has facilitated an improved understanding of sulfide mineral leaching in cyanide solutions. By analysing for sulfide, sulfite, thiocyanate, thiosulfate and metal cyanides it is possible to show that chalcocite dissolution is a non-oxidative process in which copper cyanide and sulfide ions are formed in solution. Further, the homogeneous oxidation of the sulfide ions by dissolved oxygen is slow, but catalysed by a surface of lead sulfide or pyrite. Polysulfides may also be formed as an intermediate oxidation product and these undergo further reaction to produce thiocyanate, thiosulfate and sulfite. The leaching of copper from a pyrite concentrate sample is shown to be rapid, and accompanied by significant iron dissolution; however, the iron is not believed to be from pyrite, pyrrhotite or chalcopyrite. The rate of iron leaching and cyanide consumption is reduced by maintaining low cyanide and high oxygen concentrations. Preoxidation or the addition of lead(II) ions does not reduce the iron dissolution from this pyrite concentrate.

Jan 1, 2007

Some thirty ore minerals occur in the Mount Morgan orebody. Pyrite is the dominant mineral with chalcopyrite, magnetite and pyrrhotite major components. Gold and gold tellurides, in accessory amounts, are economic- ally important. The prevalence of volcanic rocks in the mine area and the presence of trace amounts of such minerals as cassiterite, gold, native bismuth and rutile suggest a voicanogenetic origin for the ore. The ore occurs in a breccia pipe which cuts through the volcanic and associated strata but the former existence of a syngenetic stratiform ore bed is evidenced by the presence of occasional masses of perfectly banded sulphide ore including a barite-rich "black shale" with sulphide layers exhibiting slump structures. Mineralization is thus both _ syngenetic and epigenetic. The orebody (breccia pipe) is intruded by small stock-like bodies of quartz latite which is believed to have been the upward rising magma invading the orebody of which it is the parent. This has resulted in the annealing recrystallization of the ore minerals and the quartzose gangue with a low strain rate due to magma drag and dilation during intrusion.

Jan 1, 1974

Access to land for exploration, development and mining purposes is extremely critical to the viability of the mining industry and subsequently the well being of society.The mining industry has been subject to environmental controls and considerations for the past 20 years. Today there is greater land use competition and more debate as to its use. To retain reasonable access the mining industry must comply with the rules and regulations by which it is governed.A new set of rules and regulations have been approved for use in Queensland, known as the Mineral Resources Act 1989. This Act clearly outlines the titles available and the requirements to obtain access.There are three main titles of interest to mining companies. These are an Exploration Permit, Mineral Development Licence and a Mining Lease.The Exploration Permit (EP) is for exploration purposes. Applications for EP's are assessed on their content and past performances. An EP is granted subject to a security deposit and conditions. Prior to entry the EP holder is required to inform the land owner of the proposed activities and times of entry.

Jan 1, 1990

By G Giles

One of the main tools used by mining operations to mitigate the risk of rock burst is the installation of a so-called ædynamic resistantÆ support system. Such systems are designed to absorb the impact of shockwaves created by mine-induced seismic events. Dynamic support must be strong and capable of sustaining high loads and, at the same time, they have to be flexible and accommodate large deformation. A dynamic support system is therefore a system capable of absorbing a high quantity of energy. Ground support systems are composed of rock reinforcement (rock bolts or cable bolts) and surface support (mesh or shotcrete). In terms of surface support, fibre-reinforced shotcrete is increasingly seen as the industry preferred solution when difficult ground conditions are experienced, including areas of high seismic hazard. A thick layer of shotcrete is certainly strong but it is by no means flexible. Normal weld-mesh has some flexibility, but it is not very strong. The Australian Centre for Geomechanics (ACG), in collaboration with Onesteel Reinforcing Pty Ltd, is currently working on a new high-energy absorption mesh that combines strength and flexibility. The new mesh can be installed with a jumbo, in a similar way as the widely used sheet of weld-mesh. This paper describes the development of this new mesh system.

Jan 1, 2008

This paper summarises some observations regarding the way SAG and AG mills work based on the last ten years of pilot plant operation, grinding circuit design and operational reviews for various projects in Australia and overseas. The main purpose is to promote discussion on key factors influencing breakage in a SAG mill. The focus of the paper is on two questions: How do mill lifters and liners really work and have an effect on grinding? How does the mill charge composition impact on grinding performance? The focus of the paper is on observations of mill behaviour in both pilot plant trials and plant operation, particularly on Cadia ore. DEM, by others, and JKSimMet modelling of SAG mill performance have greatly assisted in forming the ideas expressed in the paper and both are valuable tools in developing our understanding of the comminution process. Put in the æextremeÆ form the major observations and conclusions expressed in this paper are that: the main purpose of mill lifters is to reduce mill liner wear and not to promote rock breakage; the often promoted theory that balls impacting the ætoe of the chargeÆ is a dominant form of breakage is incorrect; and fines production in a SAG mill is primarily a function of the rock load mass, with a secondary dependence on ball load for any given circuit configuration.

Jan 1, 2007

By Sen G

An amount of explosives, whether it be cylindrical, spherical, etc in configuration, with a hollow cavity in one face or end is known as a hollow or shaped charge. When this charge is initiated, a focussing of explosive energy will occur within this cavity. This focussing, or concentration of detonation products creates an intense localised force greater than just the simple detonation of a conventional explosive, (without a hollow cavity). If this hollow cavity explosive is directed against a target material this concentrated force is capable of creating a deeper penetration than the same amount of explosive without the hollow cavity. If a metallic liner material is used in the hollow cavity, upon detonation of the explosive this liner will form into a high velocity penetrating jet. Depending on the explosive type and the liner material's configuration the jet tip can travel up to 10 km/s. Linear shaped charges were developed using the abovementioned shaped charge concept but instead of being formed about an axis, they are elongated and constructed along the principal axis. Therefore instead of creating a narrow circular penetration jet, it forms a thicker planar cutting jet ideal for linear cutting purposes. Using Linear Shaped Charges (LSC) for pre-splitting is expected to result in more accurate directional fracture propagation, while minimising lateral micro fractures in the surrounding rock mass which is required to remain undamaged.

Jan 1, 1995

By Ritchie AS

The principles of chromatographic and electrophoretic separations are described in simple non-mathematical language. Brief details of the analytical procedures and of equipment are given. Partial analyses of rare earth elements in monazites from four localit- ies in New South Wales are compared with analyses from other localities. The presence of uranium in two of the monazites is recorded. The occurrence of rare earths in nature is outlined and its geological significance is indicated, A low capital cost method of analysis of rare earths in monazites is Introduced.

Jan 1, 1972

It is well documented that drill and blast outcomes affect the downstream mining processes of loading, hauling, crushing and grinding but it can also significantly impact on mine profitability via dilution, recovery percentage, lump generation (iron ore), fines generation (coal, iron ore), coal loss and final wall stability. Drill and blast must therefore be optimised to improve the overall profitability via positively impacting on productivity and saleable product generation. It is however, difficult to achieve this because of the complexity of the number of parameters that must be integrated and managed across the entire mine value chain, ie the concept of æMine to MillÆ. This paper highlights, via a simple case study, the need to have a mineÆs drill and blast system both in control (so that it is predictable to a high degree) and with minimal variability (so the design actually makes it into the field). This type of management control is essential prior to optimisation work being undertaken. The æTeam ApproachÆ is discussed to illustrate the methodology of achieving drill and blast optimisation. A case study is presented to illustrate the potential benefits of this approach which in this mine represented a 27 per cent reduction in powder factor with the downstream functions achieving higher productivity with the same or reduced maintenance costs. It is essential for Australian mineÆs to implement the appropriate management strategies and experienced personnel placement to ensure that their mineÆs drill and blast system is correctly managed to facilitate the optimisation of profit. Without this, the Australian mining sector will become increasingly uncompetitive.

Jan 1, 1999

Australia is a leading producer of mineral sands and according to U.S. Bureau of Mines, produced 24, 53 and 64% of world's production of ilmenite, rutile and zircon respectively in 1983. The industry which is mainly export oriented earned in export income about $210 million in 1985. The dominant position which Australia occupies in world produc- tion of mineral sands is also maintained in many areas of research and development work on the processing and application of these minerals. Some of this research which is leading the world has been responsible for setting up industries to produce value-added and high-tech products such as synthetic rutile and partially stabilized zirconia (PSZ). The production of high purity zirconia is due to commence shortly while research in rare earths offers an exciting prospect for future Developments.

Jan 1, 1986

By Cousens DR, Benhamou M, French DH

Techniques appropriate to petrographic image analysis are being developed using digitized backscatter electron images of well characterized mineral assemblages obtained from a Cameca scanning electron microprobe. Emphasis is on developing descriptors for size, shape and association of mineral grains as these all convey important information concerning the nature of rocks and the processes that have operated upon them. Processes, for example, that could indicate the proximity of mineralization. For convenience, the work is being carried out on the PDP11/73 host computer of the electron micropt be, although it is recongnized that such a multi-user environment is not appropriate for practical image analysis. The eventual aim is to develop a low-cost microcomputer-based package for quantitative description of mineral textures and rock fabrics as an objective aid to the petrographic analysis of ores and host rocks.

Jan 1, 1989

The aim of all modelling is to replicate geological reality as closely as possible using available data. This paper is aimed at one end of the spectrum, where very limited data is combined with intuitive geological ideas to synthesise models for either target definition or for determining minimum viable mining scenarios. Interactive 3D modelling allows a satisfactory hypothetical geometry of surfaces to be assembled, and provides a fast quantitative method for generating targets. As data flows from exploration, an evolving geological model assists with the progressive evaluation of a prospect. Two case histories are described where this approach has been used successfully, the Mosquito Hill Prospect in Queensland and the Longwood Ranges Platinum Prospect in New Zealand. The possibility is also discussed of hypothetically modelling an orebody which has yet to be discovered. The proper description of an orebody is the foundation upon which all mine design and planning is undertaken. The volumetric accuracy of the model is crucial in valuing an orebody. Geologists must form a geometry which matches the conceptual view of the ore occurrence and ensure that they understand how the computer system used calculates volumes. If the underlying assumptions inherent in the method conflict in any way with the conceptual model visualised for the ore occurrence, then that method must not be used.

Jan 1, 1995

During the past three years there have been several parties prospecting for oil in the Stat6 of Queensland, and It was: gratifying to read the newspaper headlines last Christmasabout the discovery of oil in the Moohie Nol Well. This discovery was not only a welcome Christmas present for Australia but marked up another success for the seismicmethod in exploration for oil.The purpose of this paper is to discuss the operationaI aspects of seismic work in Queensland with-emphasis on shot-haledrilling. The paper is based upon the experience of one particular seismic survey which began in December of - 1959 and is still inoperation. This survey is being conducted by the Petty Geophysical Engineering - Company of San Antonios, Texas, and the Queensland area involved is in the general vicinity of Quilpie, Dlackall and Charleville.

Jan 1, 1962

By Harrison J

The correct selection of equipment to use in a mine is a problem which constantly faces the mining engineer. In some cases a wide choice of equipment with different operating characteristics is available. If this equipment is to be used to assist in moving the ore it may be possible to build a computer simulation model to predict how it will perform. Typical problems that lend themselves to this type of analysis are presented. The computer models are constructed using a recent form of the GPSS computer language, namely GPSS/PC for the personal computer. This language allows the programmer to construct models in a very short time and at a low cost. Of great importance is the easy way in which it is possible to change the models to answer any of the "what if?" questions the engineer may pose.

Jan 1, 1987

By Phillips H. R

The action of free rolling disc cutters is well understood, relationships between disc geometry and performance having been established both in the laboratory and under field conditions. However, under severe operational conditions a malfunction of the disc bearing assembly is likely to produce a definite change of cutting action. Collapsed or siezed bearings can even prevent the disc from rolling and thereby create what is equivalent to a drag pick. This paper describes a programme of laboratory experiments using deliberately stalled discs. Their performance under such conditions is contrasted with that for a free rolling disc and also with a drag pick having a ridged front developing into a negative radiused back clearance angle. In conclusion an assessment is made of the influence stalled discs can have on the torque and thrust requirements for a tunnel boring machine.

Jan 1, 1981

By Kabel J. G

While a per onnel location system is primarily used to check that nobody is left in the mine at firing time, it is also useful for contacting people, uch a foremen, shiftbosses and tradesmen, who travel over several mine levels during a shift. The system installed at The Zinc Corporation, Limited, Broken Hill, uses punched coded plastic identity tags, with "In" and "Out" tag readers on each level. When entering a level, the employee inserts his tag in the "In" reader, and when leaving, in the "Out" reader. Each reader is connected to a central computer which shows who is still in the mine and their location.The system has been used on 3 levels by 21 men for a trial period of 4 months. It ha proved reliable in an underground mining environment, and employee acceptance has been good.

Jan 1, 1984

In preparation of this Paper, the emphasis has been laid on the commercial rather than on the technical and scientific aspects of coal evaluation. It is intended to describe and comment on the principal factors which currently determine the selection and procurement of coking coal for the steel industry, and is not based on the results of any original research by the author. Evaluation of different coals for strictly thermal uses, for gas production or other chemical applications has not been attempted, and comparisons of coal with other fuels have been excluded: the paper is concerned only with coals for the production of blast furnace coke. The discussion is strongly related to, and illustrated by, British, and to some extent, other Western European practice, but it is hoped that the general conclusions may have a wider application.

Jan 1, 1975

By Anderson RJ

Tower Mills are used at Aberfoyle's newly commissioned Hellyer base metal sulphide concentrator. Hellyer ore is particularly fine grained. To achieve adequate liberation fine grinding is necessary. Three Tower Mills are used on regrind duties, grinding to less than 20 microns. The physical arrangement, material flows and grinding characteristics for the Hellyer Tower Mills are described. The mills have performed satisfactorily, both in size reduction and power efficiency. Wear parts must be inspected and changed more often than with ball Mills. To date, 92 per cent availability has been achieved. As parts and maintenance routines are rationalised, this is expected to improve to 96 per cent. Modifications to wear parts for the Hellyer Tower Mills are discussed.lhc Tower Mill grinding environment is highly reducing. The impact of Tower Mill regrind on downstream flotation is discussed.

Jan 1, 1991

By J-S Zhang

In this paper, the author briefly introduces the resource characteristics of Chinese iron ore, as well as the present increasing market demand for iron concentrate. The SHP-3200 wet high-intensity magnetic separator (HIMS) is used to separate complicated weak-magnetic iron ores being composed of specularite, limonite and siderite in Jiuquan Iron and Steel (Group) Co Ltd. Some technologies have been used to improve SHP-3200 HIMS, including modifying the angle of magnetic polar from 90¦ to 83¦, cooling the exciting coils by oil instead of air, adding reverse-washing equipment to wash off magnetic particles and adjusting the tooth-space of the matrix from 5.0 mm to 3.5 mm or 2.5 mm to enhance the recovery of fine particles. It is still difficult to meet the requirement for recovering more difficultly separated iron and the demands for high-grade concentrate of iron. In order to improve the recovery of difficult-separated iron, the film-magnetic separation technique is applied into the HIMS and a new LY matrix is designed to form magnetic gradient vertically. A flowing-film feeder is also added and the feed mouth is modified to make a slurry flow formed in the form of film along the wall of matrix. The microstructure and dissemination character of the mineral particles is studied, and the specific susceptibility of the primary minerals is measured. Then the distributive characteristics of a magnetic field for the separator with film-magnetic technique and the motion of particles in the process of separation are all analysed. By introducing the film-magnetic separation technique to SHP-Φ700 HIMS, the recovery of iron can be raised from 69.45 per cent to 76.07 - 78.96 per cent with the similar grade of concentrates of iron. Such an increase of 9.51 per cent in the recovery also shows that it is feasible for such film-magnetic separation technique to be applied into HIMS.

Jan 1, 2005

This paper presents a review of heat illness in mining, including reference to several recent investigations by the author. Heat illness is a collective term, covering the conditions of heat stroke, heat exhaustion, heat cramps and miliaria rubra. Heat stroke is life-threatening and is by far the most serious condition. It is rare in mining, if appropriate control measures are instituted. Heat exhaustion is primarily due to hypohydration, following prolonged sweating in hot conditions. Symptoms include fatigue, headaches, dizziness, anorexia, nausea, vomiting, shortness of breath, or brief syncope. Confusion, ataxia, prolonged unconsciousness or convulsions are strongly suggestive of heat stroke. Heat cramps are painful involuntary contractions of skeletal muscle associated with work in hot conditions. The limbs are usually involved and the spasms typically last a few minutes, during which the affected part of the body is incapacitated. Heat cramps tend to occur in heat exhaustion, when hypohydration becomes marked. Miliaria rubra is a skin rash caused by extravasation of sweat into the skin, as a result of obstruction of the sweat glands. It occurs after prolonged and profuse sweating in hot environments. It can take three to four weeks of sedentary duties, in an air-conditioned surface environment, for the condition to resolve. Heat illness would be unlikely in underground mining, if the thermal environment was sufficiently well controlled by ventilation and refrigeration. This is however, often not practicable. Where engineering controls alone cannot provide sufficient control of risk, the residual risk can be assessed using an appropriate heat stress index. While procedural controls may further reduce the residual risk, it is important to remember that these are less reliable than engineering controls and cases of heat illness may still occur. Procedural controls include the application of heat stress limits, education, hydration, self-pacing, early symptom reporting, medical advice, acclimatisation procedures, air conditioned accommodation, support to achieve a healthy body mass index, and an effective emergency response capacity.

Jan 1, 2005

Historic mining across the Bendigo goldfield reached an average mining depth of 750 m over an area of about 16 km by 4 km, with two shafts exceeding 1400 m. Mining ceased in the mid 1900s due in part to increased dewatering and ventilation demands. Water extraction technology of the day, combined with multiple mine ownership, did not allow uninterrupted and thus economic mining activity to prosper. Today Bendigo Mining Limited (BML) is targeting gold-bearing reefs beneath the water-filled historic mine workings. To ensure mining activity can proceed without the risk of water inrush, historic workings are being dewatered by submersible pumps in historic shafts and through a series of underground drain holes intersecting old workings. Due to the high heads involved, individual drain hole development requires rigorous safety control implementation and assessment prior to drilling. Water extracted via drain holes is pumped to the surface through a series of pipe lines and rising mains in conjunction with two staged pumping stations. Both stations are equipped with high-speed centrifugal pumps, each capable of pumping 40 L/s at a static head of approximately 300 m. BML, which operates beneath and within a large city, is confronted with unusual environmental and social challenges compared to many within the mining industry. The raw mine water, which contains elevated salt levels, is piped through residential areas and must comply with strict controls to prevent impacts on the surrounding environment. The final delivery point is BMLÆs water treatment plant at the north end of the city. The water treatment plant utilises chemical pretreatment and reverse osmosis. It is able to process 7 ML of mine water per day at full production. The product is approximately 5 ML of reusable irrigation quality water, which is made available to the Bendigo community for public gardens, sporting facilities and rural irrigation. The 2 ML of brine is directed to a purpose-built evaporation pond facility located 7 km north of the water treatment facility.

Jan 1, 2008