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By Waijun Cheng, Guilin Xie

A microcomputer control system prototype of a Switched Reluctance drive for storage battery electric vehicle in coal mines is developed. The paper introduces the hardware components, the control strategy and the software unit. It is shown that

Jan 1, 1998

By Z Chang, S A. Mrozek, S Windle

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. It is important to understand skarn-porphyry transitions in order to use exposed skarns to look for associated and potentially larger porphyries. For such purposes, a good start is to understand the transition between porphyry and skarn in known deposits. In this contribution, we report the transition at Antamina, Peru, where skarns occur in and around a Miocene complex comprised of more than seven porphyritic intrusions. There are three types of skarn-porphyry relationships. The earliest intrusive phase, P1A, contains both endoskarn and porphyry-style quartz veins with secondary biotite halos. The porphyry quartz veins and endoskarns formed at the same time. Locally, the intrusion contains only endoskarn without porphyry quartz veins and is surrounded by exoskarns in carbonate wall rocks. In the third scenario, later porphyry (P2) intruding into P1A porphyry and skarns related to P1A contains abundant granular quartz veins and secondary biotite alteration but does not have significant endoskarn. The granular quartz veins also extend into earlier P1A skarns. The scarcity of endoskarn associated with P2 is related to the supply of Ca. The earliest P1A intrusion intruded into carbonates that supplied abundant Ca, therefore both endoskarns and exoskarns formed. In contrast, where the wall rocks of the later P2 intrusion are P1A or skarn related to P1A, there was little free Ca, therefore only porphyry-style quartz veins formed.CITATION:Chang, Z, Mrozek, S A, Meinert, L D and Windle, S, 2015. Skarn-porphyry transition – an example from the Antamina skarn, Peru, in Proceedings PACRIM 2015 Congress, pp 409–414 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

THE slag from the blast furnaces having been granulated, a representative sample is taken to the sample mill. It is then dried, crushed through a 100-mesh screen, intimately mixed, and packeted for assay purposes.METHOD OF ANALYSISINSOLUBLEWeigh 1 grm. of the finely-pulverized slag into a 3t-in. casserole, moisten with a little water to prevent sticking, cover with a clock glass, and add 20 cc. of hot acid (1 HNOs, 3 HCI, 4 H2 0). Evaporate slowly to dryness on a hot plate and bake (without overheating) until all the gelatinous silica is dehydrated. Cool, add 20 cc. HCI (1-1), and boil gently for several minutes; filter into a 300-cc. beaker, cleaning out the casserole thoroughly with a rubber-tipped glass rod. Wash residue with hot distilled water and transfer it to a No. 1 porcelain crucible. Dry, ignite, cool in a desiccator and weigh as total insoluble matter. Dilute filtrate to 200 cc. and neutralize some of the excess HCI with NHa.OH. Warm, and pass H2S for 15 min. Filter and wash withhot water. Boil off H2 S, oxidize with 5 cc. HNOll , reduce bulk of the solution by evaporation. to about 100 cc., and transfer to a 250 cc. flask.SILICAFuse insoluble residue over a blast lamp in a platinum crucible with three or four times its weight of anhydrous carbonate of soda, for 10 to 15 minutes, or until decomposition is complete. Cool, and extract fusion in an 8-in. evaporating dish with HCI (1-1); rinse crucible and cover with distilled water, and evaporate to dryness over a water bath. Take up dry mass with 10 cc. strong HCI, and then.

Jan 1, 1922

By G W. Wilson, C Panidis

Potentially acid forming (PAF) waste rock contained in dumps formed as a result of open cut mining of metalliferous orebodies are conventionally sealed or covered using a near-saturated, low permeability compacted clay layer, protected with a mulch layer and/or vegetated growth medium. The purpose of the compacted clay layer is to limit oxygen diffusion and the infiltration of rainfall into the dump. Where the aerial extent of the PAF waste rock dump is large, or where suitable clayey material is in short supply, it may be difficult to source sufficient suitable clayey material to form the cover. The paper describes a laboratory-based investigation of combining inert waste rock and tailings to form an alternative seal or cover material. The inert waste rock was sourced from the trafficked surface of a non-acid forming (NAF) waste rock dump, with a maximum particle size of about 100 mm. This was combined with NAF thickener underflow tailings slurry in various mass ratios, and the resulting mixtures tested for their particle size distribution, compaction characteristics, soil water characteristics (relationship between suction and volumetric moisture content), and saturated hydraulic conductivity. The mixtures tested ranged in consistency from those dry enough to be compactable, to those with the consistency of wet concrete that lend themselves to placement without the need for compaction. The laboratory test results showed that the suitability of the mixtures as seal or cover materials is very dependent on the particle size distribution of the mixture, with well-graded mixtures having substantial fines performing best.

Jan 1, 2003

By Chugh Y. P

A simplified, three-dimensional, time-dependent, mechanistic model of the overburden-coal seam-floor interaction has been developed and validated at two Illinois coal mines. The model based on the thin plate theory can involve any complex layout of mine workings, time-dependent sequence of extraction and, rheological properties of immediate floor strata. The model output data consist of spatially distributed surface subsidence and its slope and curvature, as well as load acting on pillars in one or more panels. A comparison of calculated and monitored surface subsidence or in- mine convergence measurements has proven the model's effectiveness for surface subsidence and load transfer Prediction.

Jan 1, 1992

By Coppock BW, Scott TC, Firkin GR

The pollution control measures taken on the Imperial Smelting Process (ISP) operated at Cockle Creek are described together with environmental monitoring strategy and the statutory restraints applied in New South Wales. An outline of developments in the gaseous, liquid and noise control areas is given.

Jan 1, 1975

Misima Mines Pty Ltd (MMPL) operates a large open cut gold mine on Misima Island in the Louisiade Archipelago in Papua New Guinea. Misima Island lies approximately 600 km east-south-east of Port Moresby. The island is 40 km long by 10 km

Jan 1, 1994

By Mules GJ

Geotechnical investigations have played a key role in influencing decisions for development of the Porgera Gold Project in the highlands of Papua New Guinea. Porgera is located 130 km west-northwest of Mt. Hagen in steep mountainous terrain with high rainfall. Much of the site is underlain by weak mudstone of the Chim Formation and creeping colluvial soils. Landsliding is common on the steeper slopes and in the valley floors. Structures have had to be sited to avoid areas susceptible to these movements. Early stage feasibility investigations included studies of tailings dam and waste rock dump sites, processing plant sites and hydroelectriic schemes. Further studies, leading into the design stage included the Enga Highway upgrading, water supply and power supply schemes. As construction for the project proceeds geotechnical input remains at a high level, with emphasis now on maintaining viable stable sites and refining data on which designs were based.

Jan 1, 1990

By S D. Golding

The current study integrates hydrogeochemical and stable isotope results to investigate the sources and evolution of acid mine drainage at the historic Mount Morgan gold mine in Queensland, including the controlling factors and mechanisms of sulfate formation. The open pit and seepage sumps contain acid-sulfate waters and show elevated Al, Cu, Fe, Mn, Pb and Zn values. Samples collected from the Dee River bordering the mine site are less acidic, with lower concentrations of dissolved metals that gradually attenuate downstream from the mine. Concentrated acid mine waters has lead to formation of efflorescences consisting mainly of hydrous Fe-sulfates. The results of the ongoing isotope analyses on water samples show distinctive grouping of the data. The range of the sulfur isotope values for dissolved sulfate in samples from the open pit and sumps (d34S = 2.1 to 3.0 per mil) are similar to those of sulfides in the Main Pipe mineralisation (d34S = - 0.2 to 2.8 per mil). The lack of fractionation between sulfides and sulfate indicates that intermediate oxidation states of sulfur are not significant and makes this technique a useful tracer to identify the sources of sulfate. The Dee River samples, on the other hand, have heavier sulfur isotopes (d34S = 2.8 to 5.0 per mil). These samples may contain dissolved sulfate from æinternal sourcesÆ in the river basin, show local bacterial reduction or indicate a simple mixing trend. Further isotope analyses including oxygen isotopes of dissolved sulfates will enhance the interpretations.

Jan 1, 2003

THE reduction of iron from the ferric to the ferrous state prior to its titration by permanganate or dichromate may give erroneous results in the presence of other reducible metals such as titanium. Stannous chloride and metallic zinc both reduce tetravalent titanium to a lower form, and so increase the consumption of the oxidizing standard: solution. Sulphuretted hydrogen and sulphurous acid do not reduce titanium, but are slow in action and troublesome to manipulate.Sulphuretted hydrogen is considered to be the best reducing agent for iron in the presence of titanium.* In the method to be described the advantages of the H 2S reduction are retained without the disadvantages of using the gas. The reduction is carried out by the action of a metallic sulphide having a solubility product of such a value that the sulphide iom, are utilized as fast as they are formed, and but little free sulphuretted hydrogen is given off.Cadmium sulphide was the first to be tried, but its solubility product (3.6 x 10 - 2~)t was apparently too low. The reduction was satisfactory, but the excess was very difficult to remove. Zinc sulphide (S.P. = 1.2 x 10 - 23) was found to be quite satisfactoryin both respects. The zinc sulphide is preferably used in the form of an emulsion prepared from pure zinc sulphate as follows: About 100 grm. of ZnS047H20 is dissolved in 2 litres of water. H2S is passed until no further precipitate is obtained, the acid formed being barely neutralized from time to time by the addition of ammonia. The precipitation of the sulphide in a slightly acid solution gives a finer emulsion than that prepared in an alkaline solution, and any iron present remains dissolved. The precipitate is allowed to settle and the clear liquid decanted. The precipitate is then shaken up with more water, acidified with a little sulphuric acid, allowed to...

Jan 1, 1922

Studies of the minor element content of sphalerite and pyrite have generally been concerned with individual deposits or localised groups of deposits. However, a small number of more regional investigations have been reported (e.g. Davidson, 1962; Groves and Loftus-Hills, 1968; Loftus-Hills and Solomon, 1967; Price, 1972; Bralia et al., 1979) which have used the minor element abundances to evaluate the petrogenesis and geological affinities of diverse ore types and to fingerprint metallogenic provinces (e.g. Ivanov, 1964). While generally held to be valid, some doubts have nevertheless been cast on the reliability of minor element abundances in petrogenetic deliberations (e.g. Mercer, This paper reports on the distribution of he. Cpl and Mn in sphalerite, and Co, Ni and Mn in pyrite, from sulphide mineral occurrences within the "eugeosynclinal" prism comprising the New England Region of north-eastern New South Wales and south- eastern Queensland (Fig. 1). The occurrences examined are representative of two well-defined styles of mineralisation (Stanton et al., 1974) within which clear patterns of ore-rock distribution give rise to specific metal associations (Herbert. 1977).

Jan 1, 1987

By Dunne R, Defilippi J

Dump leaching began at Teller in late-1988 at a rate of 4 MTPA and has been progressively expanded to the present rate of 10 MTPA. Teller's on-going commitment to dump leaching is driven by the amenability of gold ores to the process and the availability of large tonnages of low grade gold ore. The sequence of evaluating ores for dump leaching involves rolling bottle tests on coarsely ground ore, followed by small and large column leaching and finally trial heaps. Trial heap tests are very expensive and an alternative approach to this is large diameter column leaching.A four-column permanent facility was built at Teller to specifically evaluate the leaching characteristics of new dump leach ores. Details of construction, operation and dismantling are discussed in the paper. Capital cost for the four column facility was some $45 940, while operating costs are about $24 800 per column.

Jan 1, 1992

Epicentres of recent shallow earthquakes in the region (3-12¦S, 126-150`E) were plotted to identify the various plate boundaries in the region, in particular the southernmost one marking the northern edge of the Australian plate. New and published fault plane solutions were examined to determine the style of faulting and state of stress along the Australian plate boundary. From east to west the boundary is first a subduction zone along the Solomon Islands, then a spreading centre across the Solomon Sea, a zone of compression and left lateral strike slip along the Papua Peninsula, almost pure thrusting across the centre of New Guinea and lastly left lateral strike silo through Irian Taya to the outer Banda Arc. The principal stress is very consistent, trending NW to NNW in a near horizontal plane, from the triple junction of the Pacific, Solomon Sea and Australian plates in the east to the Banda Sea in the west. Only along southern Solomon Sea plate margin which is a divergent boundary, is the stress different in type and direction.

Jan 1, 1987

Many stress measuring instruments use overcoring stress-relief principles but adopt different sensing techniques. Every technique is subject to certain limitations of rock types and conditions. To investigate the performance and reliability of the instruments in field measurement, a simple and practical approach has been developed to allow comparable laboratory results to be obtained which simulate in-situ rock and stress conditions. Four commonly used devices, the USBM deformation gauge, the CSIRO HI cell,the CSIR triaxial cell and the UNSW SI cell were thoroughly tested in the laboratory. Some conclusions have been drawn as to their suitability and reliability in different field conditions. Recommendations are provided for the choice of an appropriate technique for a given rock type and condition. A new thin-wall cell that overcomes the disadvantages of earlier devices has been developed and tested. Its laboratory performance shows that it has good prospects.

Jan 1, 1990

The output of Dexin Pit Copper is up to 33 million tonnes a year and the final depth is more than 500 m. As a cost reduction measure, the in-pit crushing and conveying system has was introduced to deliver ore from the pit to mills. This paper describes the in-pit crushing and conveying system, and highlights the optimum level where the shovel-truck haulage system transfers into In-pit Crushing and Conveying system, relocation of an in-pit crushing system, and includes the impact of the transferring point when the costs change.

Jan 1, 2003

To meet the objectives of sustainable development, mining projects must be executed with minimal environmental risks and impacts. To allow proper actions to be taken, it is helpful if the environmental challenges associated with a mine development project can be predicted early during exploration activities. Signs of impending environmental problems like acid rock drainage and metal leaching are often revealed in the occurrence of natural acid drainage, formation of efflorescent salts and their associated ecological effects. Other subtle clues can be deduced from anomalous geochemistry, detailed textural features of mixed sulfide assemblages and miscellaneous environmental data sets covering the target areas of exploration. A more practical tool, however, is the development of comprehensive environmental ore deposit models containing relevant information on ore genesis, applicable mining, processing and waste management options and their environmental implications according to deposit type. Not only will such models facilitate communications among independent groups of personnel involved in a mining project to come up with schemes to ensure better environmental performance of the overall project, they will also facilitate decision-making if a mine development project should be pursued further or valuable resources be redirected to other more favourable targets.

Jan 1, 2003

A Master of Applied Science degree course in Mining Geomechanics commenced in 1983 at The University of New South Wales, taught by extern- al (correspondence) studies. The course is aimed at graduates employed in the mining indust- ry, and especially people involved in geomechan- ics projects on a routine basis in remote locations. This kind of course is unique in Australia and is one of only two correspondence programmes available at this University. The author designed the course and nursed it through the early years, and was Director until 1986. The paper describes the teaching and assess- ment methods and also discusses aspects of admin- istration and coordination of such a course. It is concluded that an important need of the mining industry is being catered for and it appears that similar correspondence course for- mats would also be useful in other areas of the minerals industry.

Jan 1, 1986

By B Ekberg, R Salmimies, T Kinnarinen, A HSkkinen

The regeneration of the ceramic filter medium used in iron ore dewatering is often done by combining backwashing, ultrasonic cleaning and chemical regeneration. Of these three, the first two are applied more frequently, whereas chemical regeneration is done only when needed, eg once a day. Chemical regeneration of the ceramic filter medium in iron ore processing can involve the use of oxalic acid to dissolve the iron oxide particles. Even while performing simple chemical regeneration, meaning no ultrasound to assist the cleaning, the changes in the performance and in the structure of the filter medium could not be explained solely based on the dissolution or the removal of particles from the surface. Good regeneration results were obtained at 35 and 50¦C, meaning that the final permeability of the filter medium corresponded to that of unused filter medium. Permeability of the medium after regeneration at 15¦C was also good after 12 h, but did fall short of those regenerated at higher temperatures. Changing the acid concentration did not seem to have a significant effect on the regeneration.CITATION:Salmimies, R, Kinnarinen, T, Ekberg, B and HSkkinen, A, 2013. Particle dissolution in the chemical regeneration of the ceramic filter medium used for magnetite dewatering, in Proceedings Iron Ore 2013 , pp 473-478 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By J, J M. Young, P T. Nielsen, R Zhu

Improved understanding of the variables that influence hydrocyclone performance is of increasing interest to the iron ore industry, where hydorcyclones are widely used to deslime fine ore. In many cases, the impact of particular variables is not quantified sufficiently well experimentally to ensure that industrial performance will match expectations. The current work focused on developing and implementing a systematic methodology to evaluate and compare the performance of four different hydrocyclones in a desliming application. A critical component of the project was the design and construction of a pilot-scale hydrocyclone rig using state of the art monitoring and sampling methods. A wide ranging test programme was conducted to quantify the effect on metallurgical performance of the key hydrocyclone variables such as pressure, feed density, vortex finder size, spigot size and hydrocyclone make/overall design. Details of the experimental approach are presented, along with a discussion of the sizing analysis methods used. Performance criteria were established to assess the four hydrocyclones. The effects of each major variable were quantified over a wide range of conditions. The results show that clear performance differentiation was achieved, enabling the selection of the optimum configuration. The results from this work demonstrate the benefit of objectively assessing the performance of nominally equivalent units in selecting an optimum configuration that best satisfies the performance criteria.

Jan 1, 2002

There has been much debate in the past as to whether the Australasian Institute of Mining and Meteorology ("AusIMM") should issue valuation guidelines in addition to the ASX and NCSC requirements. My experience in preparing independent expert reports has been that "best practice" sets higher standards than any laws or requirements set out by the ASX and NCSC. This is where I see the AusIMM coming in.

Jan 1, 1989