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By Yin J, Sun H

A new technology has been introduced - the use of the High-Water Solidifying Material for providing pumped roadside supports to maintain a roadway for re-use in longwall retreating. As a gob edge support, its initial use at Hebi No. 1 Colliery was successful, providing acceptable performances in support and control of convergences and lateral closures of the gob-edge roadways. This acceptability applied to both first use and re-use when the roadway became a gateroad for the adjoining longwall, remaining stable throughout the associated loadings and convergences. The technology promises economic and social benefits.

Jan 1, 1992

By Dinuzzo P, Wychie J, Desoe C

The Selwyn Gold-Copper Mine is located 150 km southeast of Mount Isa within Proterozoic units of the Mount Isa inlier (Figure 1). Mineralization in the mine area is associated with strongly sheared ironstones and iron rich schists at the base of the mid- Proterozoic Staveley Formation. The ironstone horizons outcrop as a series of dominant ridges over a 10 km strike. Economic gold-copper mineralization has been defined in 4 separate zones within a 3.5 km length of the outcropping ridges. A current combined geological resource for the deposits is 5.3 million tonnes of 5.0 g/t Au and 2.02 Cu. Weathering of the deposits has resulted in a pronounced vertical zonation of mineralogy, especially copper, within the ore zones. This has produced 3 separate ore types which require different treatment techniques. The categorization is based on copper content and zones are termed leached (surface), oxide and sulfide. Ore removed from the pits will be mainly leached and oxidized with minor sulfide near the pits final depths, while the underground ore will be from the sulfide zone with minor oxide in some areas.

Jan 1, 1989

Probabilistic seismic hazard analyses (PSHA) have now gained wide acceptance in the development of design criteria for major projects. When used with regional criteria the procedures have also allowed the preparation of more rational seismic zoning maps. Seismic zoning maps using various levels of results from PSHA studies around the Pacific Rim now include Canada, Indonesia, New Zealand and the United States. Some Pacific Rim countries such as Chile where the seismic exposure is dominated by subduction events have no subdivision into separate zones.Approaches to risk based zoning are being considered in several Pacific Rim countries including Australia. Australian studies must face problems similar to parts of the Eastern United States where seismic activity is low with irregular and infrequent occurrences of moderately large earthquakes. The perception of the seismic exposure by both regulatory agencies and the public at large is different when considering areas of low seismicity. There is therefore a need to make different interpretations of the results of PSHA studies in these areas of low seismicity. The aim of this paper is to explore some of these differences by comparing the results from two site specific studies from areas with widely differing seismic activity rates.

Jan 1, 1990

The research, development and testing of a Blast Control Plug (U.S. Pat. #4,754,705) funded by the U.S. Department of Energy is described. The plug's function is to improve blasting efficiency through the enhancement of stemming effectiveness and thereby reduce drilling and blasting costs. The plug comprises a solid unit placed in the blast hole within the stemming column above the explosive. It is designed for use with back filled drill cuttings or any other suitable material The research and development program comprised the testing of the plug in small diameter holes in competent rock for both bench and crater blasting configurations and full scale field trials in multiple hole and row blasts using blast holes of from 76 to 387 mm in diameter. Test measurements included stemming displacement and velocity, face movement and extent, peak air over pressure and ground surface peak particle velocity. Data acquisition equipment included a Spin Physics SP2000 high speed video motion analysis system, and acoustic and seismic monitoring units. Substantial reductions in stemming ejection velocity or ejection elimination were achieved whilst reducing stemming length by up to 35% over conventional practice. Peak air blast pressures were also reduced by between 8 and 25 dB. A strong inverse relationship between rock face movement and stemming ejection velocity was found. The implications of the importance of stemming effectiveness in blasting and computer blast simulation is also addressed.

Jan 1, 1990

By Cocker J, Urosevic M

Seismic methods have become common for the detection of low-throw faults ahead of underground coal mining. Surface seismic methods cannot theoretically be used where dykes occur, because seismic waves transmit from the surface down to the seams, and reflect back to the surface. Consequently, where sub-vertical structure such as dykes occurs, the surface seismic method fails.The ability of seismic methods to image dykes depends on the geometry used, the dyke thickness and the seismic wave propagation mode in relation to dyke composition and internal structure. Surface seismic methods find it difficult to distinguish between faults/fractures and very thin dykes (1-2m in thickness) when the dyke's thickness is less than the seismic wavelength. Consequently, borehole seismic methods have to be used to detect the presence of such thin dykes.

Jan 1, 1998

By Barber S

The Golden Cross Mine is located within the Waitekauri Valley near the southern end of the Coromandel Ranges, eight kilometres north-west of Waihi, North Island, New Zealand. The mine is owned and operated in a joint venture by Coeur Gold NZ Ltd (80 per cent) and Viking Mining Ltd (20 per cent). The underground mine produces gold and silver from low sulphidation epithermal quartz veins which developed in the shallow parts of a meteoric water dominated system during the Upper Miocene (7.36 - 6.67 Ma). The Empire Vein System is hosted within a dilational structural environment which developed at the lithological contact between acid intrusives, rhyolitic-dacitic tuffs and reworked pyroclastics, and undifferentiated andesites. The formation of the Empire Vein System was controlled by the rheological properties of the host rocks and variable displacement along a series of normal, right lateral, easterly-dipping faults. These faults represent sub-parallel zones of master shearing within a Riedel shear model. Underground mining extracts ore from the steeply dipping hangingwall and the complex footwall veins of the Empire Vein System. Initially sills are driven along the hangingwall vein on ten to fifteen metre sublevel intervals. In the footwall zones where significant mineralisation adjacent to the hangingwall sill drives has been identified, a series of cross-cuts and footwall drives (sub-parallel to the hangingwall sill) are also developed. Where continuity of mineralisation and ground conditions permit a combination of post pillar flatbacking and AVOCA longhole benching methods are used. Detailed underground mapping of lithology, quartz veining and major structures provides the information for designing ground support and footwall pillars, planning mine development and ore extraction sequencing. Sectional interpretation displays the vertical extent of faults, fractures and the vein system. The mining methods used underground at the mine have evolved through a thorough understanding of the structural complexity and the systematic geological mapping of the Empire Vein System.

Jan 1, 1997

By Hagan T. N

Quite apart from economic considerations, the following performance parameters must be considered when selecting an explosive for a particular blasting operation. 1. total energy yield/kg, and more particularly, strain energy/kg and bubble energy/kg of charge 2. charge weight/m of blasthole 3. sensitivity of the charge 4. water resistance of the charge The effective division of an explosive's total energy into strain energy (SE) and bubble energy (BE) is explained as is the influence of each energy component on blast results. Because some rocks require a high strain energy for effective breakage, while others are most satisfactorily fragmented by bubble energy, values of SE and BE are more meaningful than those of total energy. Unfortunately, our extensive knowledge of the effects of certain variables on total energy has not yet been completely supplanted by the influence of these variables on SE and BE values. Relative SE/kg and BE/kg values are presented for a range of explosives. The 'charge density of ammonium nitrate/ fuel oil (ANFO)-type explosives is essentially constant throughout the length of the charge; because of their compressibility, slurry

Jan 1, 1974

A 1991 survey of 48 mining companies, employing more than 24 000 employees, showed that disabling injury and disease rates continue to be the most common measurements of safety management effectivness in the Australian mining industry.Of the companies surveyed, 22 claimed to be making regular safety audits. Of these only two listed the improvement of audit scores among their goals for 1991.Influenced by loss control management thinking, some managers have expanded the scope of their safety programs to include all accidental operational losses adversely affecting mine profitability.Learning from their new experience with total quality management some managers are now recognising that successful safety management outcomes depend on the effective management of program inputs. They are thus turning away from measurements of accident consequences - the failures of the management system - to measurements of management control.The new focus of safety management attention is now on corrective actions before accidents happen.

Jan 1, 1992

The completion of the Hot Strip Mill at the Port Kembla works of Australian Iron & Steel Ltd., makes possible the production of steel plates and wide strip of a quality and in quantities not possible previously in Australia, and will also enable the production of tinplate to be undertaken in this country.The site chosen for the mill was a mud fiat underlain by a hard stone bottom at 5, to 801 feet below the surface; and a total area of one hundred acres was reclaimed to a level of 20 feet above the original surface.Three adjoining buildings were constructed to house the slab receiving yard, mill equipment and electric drive, together with the plate finishing line.After slabs have been heated to 2250°F at a rate of 90 tons per hour, they are transferred to the vertical scale breaker which is the first stand in the hot roughing mill. Here the primary furnace scale is first cracked and then blasted off by high velocity water descaling sprays.The next stand is the horizontal scale l;Jreaker, where any remaining primary scale is broken and then blasted off. After descaling, the slabs pass to the broadside mill, where short slabs are turned and rolled on broad side for wide plate.The next step is a slab squeezer which squares up the edges after broadsiding ready for the reversing mill. This is the finishing stand for plate and the last roughing stand for strip, which then passes to the finishing mill.The hot strip finishing mill consists of six stands with a maximum finishing speed of 2,230 feet per minute. Strip is cooled for coiling by water sprays on a hot run table and then coiled on a mandrel type downcoiler, from whence coils of hot strip are weighed and transferred by conveyor to the coil storage building.Plates are transferred from the reversing mill to the plate finishing line where operations consist of levelling, inspection, branding, cutting to width and length:INTRODUCTIONDue'to the increasing production of cars, refrigerators, washing machines and similar consumer goods in Australia, together with the increased requirements of galvanised iron...

Jan 1, 1956

By Crawford G. R, Wold M. B

The application of the hydraulic fracturing technique to the measurement of in situ rock stress from underground excavation is discussed; including relevant theoretical considerations, equipmenl details, experimental technique and analysis procedures. Examples of the application of the technique at three Australian coal and metalliferous mining operations are given. The results obtained from these applications are compared with corresponding results obtained from overcoring tests conducted in close proximity at each site. Generally good correspondence in a wide variety of rock types is indicated. Experience gained with hydraulic fracturing at several underground mining sites has indicated it to be a quick, cost effective means of gaining an understanding of the in situ stress field in sufficient detail for many mine planning functions.

Jan 1, 1990

By J Boland

Polycrystalline diamond compacts (PDC) have been widely used as cutting elements in the drilling tools for the oil, gas, civil and mining industries because of their faster penetration rates and longer bit life. US Department of Energy reports that PDC bits account for more than one-third of the total footage drilled worldwide (US Department of Energy, 2004). However, non-thermally-stable diamond composites (NTSDC) have seldom been applied to geothermal drilling, since premature failures of such PDC cutters have been observed in hard rock formations. Several factors need to be considered to prevent premature failure of cutters and improve cutting performance when using PDC-based bits and other rock cutting tools. The first set of factors consists of the strength, density, stiffness, toughness and thermal resistance of the PDC and the rock. A second set relates to the complex behaviour of the bonding between the PDC cutter and the bit matrix, or the pick and the pick holder, which is vital in maintaining stable, reliable and durable adhesion of the cutters to their hubs. Finally, based on a better understanding of the cutting processes, the formulation of a predictive model would assist in further development of cutter design.

Jan 1, 2004

By Kanchibolta S. S, Brunton I, Tapia-Vergara F

The Split digital image processing system has been implemented in three Australian mines for analysing the size distribution of rocks from the images taken from muckpiles, conveyor belts and tipping trucks. This paper presents an overview of t

Jan 1, 1998

By Wickham P, Raeburn M. R

The design and development of slurry sampling equipment for the Mount Isa Mines Limited on stream analysis installations is discussed in detail. Emphasis is given to the critical areas of slurry transport, screen design, pump selection, elimination of fast wearing components and maintenance reduction. Sample point design to fulfil the specific accuracy requirements for On Stream Analysis (3% to 10% relative) is discussed.

Jan 1, 1976

Blast Engineers frequently use the terminology "the blast showed good heave", or even "the heave was better this time". It is reasonably obvious that "good" and "better" are not the best terms to use. It is also noted that any variation in the data can be misleading. The author proposes a more precisely defined and objective set of measures as tried and tested in a project in 1988. Simple objective measurements of a muck pile profile can measure 1. distance thrown 2. spread of material 3. heaping of material 4. skewness, or bias in the heaping 5. rotation of the mass This technique enables one to compare the profiles from different blasts without relying on subjective experience or judgement. Simple, artificial profiles will be presented to illustrate the problems of description; and then application of the measurement techniques to these profies will be discussed with physical interpretations. The mathematical techniques will be presented, and results of the application of the techniques to real data collected during research carried out at Baimsdale in Victoria, will be presented as illustration. The use of these techniques in mathematical modelling will be discussed.

Jan 1, 1990

By Leahy G. J, Moxon N. T, Nicol S. K

Experimental work is described in which extremely dilute aurocyanide liquors are treated with novel surface-active complexing agents to produce a hydrophobic aurocyanide species. Subsequent aeration of these liquors causes accumulation of such species at the air-water interface and the aurocyanide complex is transferred to a froth concentrate. A detailed performance assessment of this process is made and this knowledge used in the design of a pilot plant facility. Early results indicate the feasibility of the selective recovery of aurocyanide ions from reclaimed residue dam water (approximately 0.2ppm Au) with upgrade ratios of the order 180:1. A further study was made applying ion flotation to the recovery of gold from a carbon-in-pulp (CIL) feed liquor (approximately 1.0ppm Au). The probable economics of this process compared to conventional CIL processing is also described. Successful development of countercurrent ion flotation for concentrating solids-free gold solutions may offer a lower cost alternative to existing gold ore processing technologies, or in more secondary applications such as concentrating dilute gold solutions or heap leach runoff. The technology may also have more generalised applications to other heavy metal process- Ing.

Jan 1, 1991

By McGhie R. R

The general structural features and the principal mineral relationships of the Black Star ore body, Mount Isa, Queensland, have been described in several previously published papers. But particular reference may be made to the work of Grondijs and Schouten, whose examination of over 200 polished sections revealed some remarkable features in the process of ore deposition. The observations by the present authors are based upon the study of a smaller ·set of specimens complementary to those examined by Grondijs and Schouten and are intended to elaborate certain aspects of the mineral relationships, more particularly those affecting the ore-dressing processes.The work described applies to the primary sulphide ore only, and to the present milling practice of fine-grinding and selective flotation.GEOLOGICAL FEATURESThe Black Star is one of several economic mineral concentrations in the Mount Isa series of thinly bedded carbonaceous shales, which are considered to be of preCambrian age. The nlineralization is apparently connected with pegmatite intrustions located within some miles of the ore bodies, and has been Gontrolled in the main by major folding of the shales and by a shear system which follows approximately the strike and dip of the beds. The detailed "The investigations described in this paper were made in the Metallurgy Department, University of Melbourne, where the senior author was formerly Senior Lecturer in Mining and Metallurgy. A report on a section of the work was submitted by the junior author as a thesis requIred by the University of Queensland.

Jan 1, 1939

The moisture content of clean coal contributes significantly to the product's transportation costs, handleability characteristics and/or energy value. A major contributor to the total moisture is the ever increasing proportion of fine coal in

Jan 1, 1994

By Xu C

This paper describes the structure and operation of an interacth.. computer program for mineral industry financial analysis and production planning. It includes comprehensive risk analysis with correlated variables and optimal production scheduling using Lane's balancing cut-off grades and the general dynamic programming approach.

Jan 1, 1995

The diverse nature of inadvertent mine fires does not lend them to general treatment. But evolving from the unfortunate fires over past years is a simple principle in dealing with all fires to bring combustion under control. Control, in brief, means that the products of combustion, themselves possibly still with fuel values, are not revitalised by addition of fresh air. There are problems with fire- fighting, especially with water, as this may lead to production of CO and H2. Panel ventilation upstream of the fire must be controlled to direct all air over the fire. Some advantages in fire fighting are found by the use of "sails". Early diagnosis of fires and early treatment are essential for safety of personnel and safeguarding and recovery of property. Preparedness extends to up to date documentation, but first hand knowledge also is invaluable to the diverse personnel gathered to fight a fire, and in the decision making Involved.

Jan 1, 1981

By Aspinall T. O, Just G. D

Computer software systems have been developed to assist in a wide range of specific mine planning and scheduling applications. In selecting appropriate systems for any mining operation it is apparent that certain features have particular advantages for each mine site. The ideal solution to this problem is to select a range of systems which best relate to sections of each mining operation. This approach raises potential data linking difficulties where output from one system is incompatible with input requirements for other systems. A study at the University of Queensland investigated the problems related to the integration of a number of mine planning and scheduling software systems. The project used data from large scale coal strip mining operations in Central Queensland. Two major computer packages used extensively in the study were the SURPAC mine planning and XPAC mine scheduling systems. Dragline and truck and shovel operations were analysed in the project. Results of the work have been directly applied at the mine site to assist current strip design by effectively automating the design procedure. This enabled sensitivity studies to determine the effects of changing dragline working levels and varying pit dimensions. Coal blending studies and procedures to optimise operations have been investigated using linear programming within a spreadsheet software application. Output from the SURPAC and XPAC programs was directly linked to the linear program for this analysis. The simulation program GPSS/PC was also used in a similar manner to assess optimisation parameters.

Jan 1, 1992