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By H A. Challenor

Eyewash safety showers located in remote hot environments may be unsafe to use due to excess water temperature and high risk levels of water borne bacteria such as Legionella. Australian Standard AS 4775 specifies that dispensed water shall be bacteria free and have a maximum temperature of 37.8°C. Legionnaires disease is contracted when water aerosols containing Legionella bacteria are inhaled.Laboratory tests show 30 to 70 times more aerosols are generated by showers operating at 38°C than with showers operating at 25°C. Furthermore, excess temperature in flushing water can cause burn injuries leading to hospitalisation, skin grafts and/or permanent scarring. Excess temperature also increases the rate of reaction to corrosive substances, opens pores in the skin to allow greater dermal penetration and can cause dizziness and fainting by dilating blood vessels and reducing blood pressure.CITATION:Challenor, H A, 2017. Managing excess temperature and high risk levels of Legionella bacteria in eyewash safety showers, in Proceedings Iron Ore 2017, pp 337–346 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

On the basis of field observation, four principal styles of hydraulic breccia are recognised, and their characteristic features noted. In practice, hybrid styles are most commonly encountered. Numerous examples will be illustrated during the oral presentation, and the potential for definition of a formative environment is emphasised. In one example presented, it is suggested that more than 50 episodes of hydraulic fracturing can be recognised. In all cases at least sane useful conclusions can be drawn in the context of modeling for drill targets.

Jan 1, 1987

By I M. Platten, C J. S Sangster, Y Xie

The Cononish gold-silver deposit is a steep, relatively narrow quartz-vein system, with a current total mineral resource of 154 000 oz Au and 589 000 oz Ag. The northeast-southwest trending system was emplaced into late Proterozoic metasediments, and postdates metamorphism and associated Caledonian Orogenic foliations. Assay and mineralogical data show that gold and silver is spatially associated with sulfides in quartz. The main sulfide is pyrite, but galena, chalcopyrite and sphalerite occur in small amounts. Gold occurs as electrum, with minor native gold, and silver occurs additionally as tellurides and native metal. The gold/electrum is fine-grained, generally less than 100 microns in size. The main ore shoots plunge 45¦ south-west, have a 40 m to 80 m intersection with the existing underground development and extend between 40 m and 260 m down plunge. Small-scale sulfide-bearing domains within the vein carry the highest gold grades. They collectively define the ore shoots, where one or two, and rarely three, of the domains are present at an individual site in the vein. Discontinuity of individual domains, variation in domain thickness and internal heterogeneity results in short scale variation in grade across the structure. Geological mapping along a 1.2 km exploration adit has provided critical æconditioningÆ data to support resource evaluation based on development and relatively wide spaced drilling. In addition, it has provided an indication of potential challenges that could be encountered during production.

Jan 1, 2009

By Hoskings R

Conceptual studies of the run of mine stockpiling and reclaiming requirements at Thiess Bros Pty Ltd South Blackwater coal mine commenced in 1975.Final selection of equipment was made in 1978 and the equipment was commissioncd in June 1979. Equipment selection was made after extensive investigation and visits to existing facilities throughout the world.The equipment selected is described and compared with the alternatives. Foundations were designed to minimise clean up effort and to ensure stabilily of equipment under design wind loading without storm bays. Programmable logic control enables the stacking and reclaiming facility to provide a blended feed to the coal preparation plant.

Jan 1, 1981

By Dippenaar R, Evans T

Twin-roll continuous casting technology is rapidly approaching commercialisation. Fundamentally different than conventional continuous casting, heat transfer and hence solidification during twin-roll casting are governed by the interfacial melt/mould thermal resistance, as opposed to the resistance of the solidifying shell. Under these conditions the interface resistance is predominantly controlled by the melt/substrate wetting behaviour. The very early stages of melt/mould contact are characterised by highly transient heat transfer conditions. The overall melt cooling rates prior to the formation of the first solid are reported to be in the range of 1000 - 50000 K/s with melt undercoolings of up to 300 K. At the points of intimate melt/mould contact the thermal resistance is approaching zero, where cooling rates and undercooling much larger than those reported in the literature are probably occurring. Improved wetting will reduce the energy barrier for nucleation while at the same time increasing the cooling rate of the liquid. Since the overall nucleation rate is controlled both by the rate of cluster formation and the rate of atom transfer to the nucleus, a critical cooling rate will exist above which the nucleation rate is expected to be reduced. Under these conditions, it is possible that the first solid phase to form is a metastable glass which subsequently transforms into a crystalline phase. The implications on nucleation and early growth are also discussed.

Jan 1, 1999

By M Hourn, D Turner, P Voigt, D Mallah

The GPM Gold Project is located in Armenia, and consists of an open cut mine at Zod, near the Azerbaijan border, and a CIL processing plant at Ararat near the Turkish border. Mining at Zod commenced in 1976, and focused on near surface oxide ores, which overlay deeper refractory sulphides. Historical mining has now almost depleted the oxide ores, and the sulphide content of ore delivered to the processing plant at Ararat is increasing. Gold and silver recoveries through the Ararat plant were declining steadily.GeoProMining, the owners of the project, have expanded the Ararat facility to deal with the increasing sulphide content in the ore. In 2014, GeoProMining refurbished an existing concentrator on site to recover a sulphide concentrate from the ore, and have constructed an Albion ProcessTM plant to oxidize the refractory concentrate. Glencore Technology (GT) provided the Albion ProcessTM plant as a technology package.In July 2014, the progress of the GPM Gold Project Albion ProcessTM Plant was reported (Hourn, Voigt and Turner, 2014). At the time of writing, the construction of the plant was nearly complete. This paper presents an update of project progress, covering commissioning and ramp up of the GPM Gold Project.The commissioning phase occurred over June to August 2014, which included an M3,000 IsaMillTM fine grinding plant, a 6 tph limestone milling plant, a 60 tpd vacuum pressure swing adsorption oxygen plant, a 10 m residue thickener and a 12 tph Albion ProcessTM oxidative leach plant. Since commissioning was completed, ramp up occurred over the following three months with downstream gold recoveries from cyanide leaching reaching over 98%.CITATION:Voigt, P, Hourn, M, Mallah, D and Turner, D, 2015. Commissioning and ramp-up of the Albion Process at the GPM Gold Project, in Proceedings MetPlant 2015, pp 207–219 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

The granulites and related "dry" igneous rocks tend to be passed over during exploration for metals. Preliminary data show that high trace concentrations of eu, Ni, and other metals of economic interest are commonin orthopyroxene and some of the other granulite minerals. During retrograde metamorphism of granulites, pyroxenes are converted to amphiboles or phyllosilicates, and significant quantities of metals are released andbecome available for incorporation into new mineral phases, or may be transported elsewhere. S-rich scapolite is the normal scapolite of granulites. Its retrogression to secondary plagioclase provides much S which scavengesCu and Ni, from pyroxenes undergoing retrogression, thus producing ore-fluids. A full analysis of a scapolite with 5·10 per cent SOg is given.Beryl is unstable in granulites but the rare Be mineral taaffeite (Al4Mg(Be, FeII)Os) with 5·50 per cent BeO occurs in central Australia as a pale green tabular mineral easily confused for chloritoid in hand-specimen.Metamorphic differentiation and mobilization of primary ore concentrations are major factors controlling their post-granulite attitude and grade.Zones of retrograde metamorphism are commonly found cutting or engirdling granulite terranes. As the "volatiles" for the new hydrous minerals of many of these zones are of deep-seated origin and may be juvenile, sulphide mineralization in them may also be of mantle origin. However, it is likely that much of the metal content could be scavenged from the granulites as they are down-graded by juvenile volatiles. Major Bouguer gravity anomalies delineate some granulite terranes (e.g. Fraser Block, Western Australia), and are related to deep-seated geosutures and mantle disturbances.Many granulite terranes are linear belts and appear to be welded to older cratonic blocks.

Jan 1, 1969

The Electricity Generating Authority of Thailand (EGAT) Mae Moh coal mine is an open-cut coal mine in Thailand that produces about 16 Mt of lignite annually to generate 2400 MW of electricity. The surface mine pit covers is 4 km by 7 km with mining depths ranging up to 260 m. A large pit slope is formed with the progression of the mining operation. However, massive slides in the pit slope occur often due to the existence weak planes such as faults and bedding, and the weak mechanical properties of the rocks. Hence, 200 m to 300 m boundaries of rock block including coal seams are left in front of faults in order to prevent slides and maintain the stability of the pit slope. As a result, there are significant coal reserves beneath the abandoned area along the pit slope. Moreover, the mined coal seams are very thick and their thickness range from 15 to 30 m.This paper discusses the application of multi-slicing highwall mining system with stowing to this very thick coal seam left around large pit slopes by means of numerical analysis.

Dec 6, 2010

As the chief field of the gold dredging industry in Otago is the district traversed by the Molyneux River (called above Cromwell the Clutha) and its tributaries, a brief reference to the geology of that region and the origin of its alluvial gold will not be out of place. The prevailing rocks are metamorphic schists, chiefly mica and quartz schists, pr.obably of Silurian age. Though these rocks do not contain many payable quartz reefs, gold appears to be distributed in small quantities all through them,chiefly associated with the quartz lamime and lenses. The river drift, however, contains numerous pebbles of quartzite, quartzoze conglomerate, and fme-grained slate. Seeing that these rocks are hardly known to occur in situ within the watershedof the Molyneux River, though Devonian and carboniferous rocks of similar character occur to the north-east and south-west, it seems probable that the schists were at one time overlaid by carboniferous and Devonian rocks, and that these have been removed by denuding agencies. Be this as it may, it is certain that the schists themselves have been greatly eroded by the action both of water and of ice, and that the resulting drifts have themselves, in many cases, been sorted and re-assorted by the same agents.Consequently the drifts are very varied in character and often developed on a grand scale. In geological age they vary from Early Tertiary (though some may be older) to Recent.

Jan 1, 1903

THE Talisman mine is situated on the Waitawheta (pronounced Wytaffetta) river just above its junction with the Chinemuri (pronounced Chinnemurre) river near Karangahake, NZ. The explored reef-bearing portion of the claim includes the angleformed by the junction of the rivers and extends southwards for slightly over a mile (See Plate V.). The country is mountainous both rivers flowing through precipitous gorges.The trig. station on Karangahake mountain is almost directly above the workings on the Bonanza section and is 1680 ft. above river level, the adit from the gorge giving 1200 ft. of backs measured vertically. The officers of the N.Z. Geological Survey are engaged in a detailed survey of the Waihi district and the rocks of Karangahake are under examination. The rocks of the district are andesites and dacites much altered and silicified. One of these exhibits a columnar structure in the mass in the Waitawheta gorge near the surface workings on Taukani hill, also on the southern bank...

Jan 1, 1912

By Reeves M

A review of the literature available in English on kriging and geostatistics is given with the references cross-classified by their subject matter for convenience and ease of use.

Jan 1, 1979

Electroosmotic Dewatering and Consolidation of Mineral Waste Tailings

Sep 13, 2010

By J E. Everett, K Jupp, T J. Howard

Precrusher stockpiles are designed principally as buffers to decouple the mining and processing operations. They are usually paddock dumped or dumped over a face to form fingers by dumping haul truckloads and reclaimed by front-end loader in an ad hoc manner. In addition, they are often not built and reclaimed to completion but continually added to and extracted from. While this design suits the mining process and is operationally simple, there can be little confidence in the grade of the ore that is fed to the crusher. This makes short-term grade control difficult and reconciliation back to the mine face imprecise. Well-designed and operated precrusher stockpiles can overcome these deficiencies.The different types of grade variability in mining are reviewed in this paper. The role of precrusher stockpiles in reducing short-term variability is discussed and their ineffectiveness in addressing long-term variability is highlighted. Their role in removing the serial correlation of the extracted ore is explained.Precrusher stockpiles carry out the four, at times competing, objectives of storing, buffering, blending and grade separation. Their actual design and operation result from a compromise between these four competing roles. These roles are explained in detail along with the advantages and disadvantages of the different types of precrusher stockpiles. The recommended blended-in blended-out stockpile (BIBO) design is discussed in detail. Matched pairs of BIBO stockpiles of limited tonnage built and reclaimed to completion retain the best knowledge of grade and facilitate the reconciliation process.Simulation studies have been carried out on BIBO stockpiles to understand the blending opportunities of the different options for building and reclaiming, and to identify the methods that achieve maximum blending. It was found that laying down rows in one direction and reclaiming across these rows gives the best blending. Matching the width of the reclaim face with the daily crushing requirements is also important. The length of the rows, and building in either one or two layers has little effect on the extent of blending.Appropriate design can provide a reasonable compromise between the four objectives.CITATION:Jupp, K, Howard, T J and Everett, J E, 2013. The role of precrusher stockpiling for grade control in mining, in Proceedings Iron Ore 2013 , pp 203-214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

The great problem at Port Pirie and many other lead smelters has always been to keep the lead content of the slags down to a low level. This has been done in the past largely by empirical methods, the lead content varying from less than 1 per cent to over 4 per cent, the more usual figure being something under 2 per cent. Subsidiary to this, but of major importance in the future, was the extraction of the considerable quantities of zinc in the slag. At this stage little was known about the constitution of the slags apartfrom their chemical composition. Some early work on slag constitution was carried out in the B.H.A.S. Research Laboratories between 1919 and 1921, but except for a microscopic examination of a few thin sections the greater part of this investigation wasdevoted to the recovery of the zinc content of the slag by leaching methods.In 1949, therefore, it was decided to initiate a programme of fundamental research into the constitution and properties of the lead blast furnace slags. The information thus gained would give a clearer picture of reactions taking place in the slag, both in the blast furnace and during dezincing.There was also the hope that these results would lead to improved industrial techniques resulting in smaller lead losses, and, taking the long-term view, to efficient methods of producing zinc from the slags.A series of investigations was therefore begun at various centres over a period of time. These were:1. A mineralogical examination of the slags by Dr. A. B. Edwards of the Mineragraphic Section, C.S.I.R.O.2. A study of the thermodynamics of various slag com...

Jan 1, 1956

By Cadia Geology Team

The Cadia Hill Gold Mine, located near Orange in Central Western New South Wales, is owned and operated by Cadia Holdings Pty Ltd, a wholly owned subsidiary of Newcrest Mining Limited. Construction including pre-strip mining occurred from 1996 to 1998. The mine was officially opened in October 1998 following commissioning of the concentrator and mine fleet in June of that year. The Cadia Hill orebody is a porphyry related gold and copper system. The final pit has a strip ratio of approximately 1.3:1.0. Mining is undertaken on 15 metre benches using large capacity diesel hydraulic face shovels at an annualised rate of up to 70 Mtpa. The concentrator is currently rated at 17Mtpa and includes the worldÆs largest single line grinding circuit. The feasibility Mineral Resource was estimated at 352 Mt at 0.63 g/t Au and 0.17 per cent Cu. Initial reserves totalled 200 Mt at 0.74 g/t Au and 0.17 per cent Cu yielding a mine life of approximately 12 years. During the pre-production period mine geology systems were developed to support the operation. By design these systems were intended to add value to the business through minimisation of material miss-classification, provision of accurate and timely production information and mapping and reconciliation as a continuous model improvement tool. Variances that would prove to be material to the life of mine plan were recognised during the first year of production. These included identification of additional ore tonnes, higher copper grades and higher gold recoveries relative to the model. Gold grades and copper recoveries also reconciled favourably. Testwork was undertaken to determine the underlying causes of each variance. Re-modelling was then undertaken to capitalise on those variances. The Cadia Hill Gold Mine life of mine plan was re-evaluated with updated geology, grade, geotechnical, metallurgical and environmental inputs. Operating strategies were also reviewed and revised. Despite application of reduced metal prices in the evaluation, the outcome was one of extended mine life with more metal produced at lower cost. Development of robust mine geology systems, including a pro-active reconciliation process contributed to tangible improvement of the Cadia Hill Gold Mine operation. On-going system development and improvement initiatives are planned to add further value for the future.

Jan 1, 2000

A new test coke oven of 7 cu. ft. capacity is described. The oven was designed to simulate conditions in a central section of a battery oven and a special feature is the achievement of unidirectional heating from theflues on either side of the charge.The method of charging permits close control of charge conditions such as bulk density and moisture content.These conditions, as well as coking conditions (e.g. flue temperatures and coking time) must be varied to simulate conditions in different batteries. The effects of several variables on coke quality are discussed.Using test oven conditions corresponding to those of Newcastle steelworks batteries, good agreement was obtained between strength indices of test oven and battery cokes. For 17 tests, the average ASTM stability and hardness indices for the test oven coke were 38· 5 per cent and 69·7 per cent, while those for the battery coke were 37· 4 per cent and 67·6 per cent.Observed relationships between coke yield and productivity, and volatile matter and charge moisture are given.The use of a test oven to classify test coals into prime-, medium-, poor-, and non-coking coals is discussed.This may be achieved by observing the effects of the test coal in blends with other coals. The results of a series of blending tests are presented.The dangers of attempting to predict coke quality from a single coal property are pointed out, since this can be done only for very restricted ranges of coals.A diagram is given showing the established trends in the effects of blending various types of Australian coals on coke strength.

Jan 1, 1970

The modern Golden Cross mine entered the production phase in January 1992. The project is designed to produce over 100 000 oz/yr of gold and over 300 000 oz/yr of silver during a mine life of eight years. An open pit and an underground mine are operated producing around 850 000 t/yr of ore, to feed a conventional carbon-in-leach processing plant. Golden Cross is owned in joint venture by Coeur Gold New Zealand Limited (80%) and Viking Mining Company Limited (20 %).   Since the start of production several major aspects of the design have altered. The underground mine began as a mechanised cut and fill operation. The cut and fill stoping progresses in 3.3 m flatback lifts with maximum stoping width of 6 m. Where the ore zone is wider than 6 m a post pillar cut and fill method is used. In 1993 a new bench mining plan was introduced between the 270 and 260 levels. Flatbacking continued in the footwall drives in anticipation of variability of the ore width and orientation. The development of levels below the main service 200 level has indicated a possibility of bulk mining the ore block rather than flatbacks. This could lower mining costs but also introduce higher dilution rates. Development is in the advanced stages for trialing this method.

Jan 1, 1994

Trends in Test Filtration to Respond to Decreasing Sample Size There has been a steady decline in the quantity of samples available for testwork when developing new mining processes due to the maturing mining technology and the increasing costs of pilot testing. Larox, a supplier of filtration equipment and its co-operation partner Lappeenranta University of Technology (LUT) have been actively developing new equipment, testing methodologies and tools to plan test campaigns with the objective of being able to determine the optimum filtration technology and the parameters for sizing full scale equipment with a minimum sample size. With smaller sample sizes, the test scale diminishes from pilot scale to bench scale, and the small equipment size has implications for scale-up. Redesigning the equipment to simulate full scale equipment rather than to match filtration theory has led to some interesting developments. Comparisons between bench scale equipment and production units help identify the limitations of bench scale testing. The nature of filtration is such that it is unreliable to estimate filterability theoretically, and different testing methodologies have been investigated to be able to test the feasibility of filtration from samples as small as few grams. While not optimising the filtration technology, these methodologies provide an adequate level of accuracy for scoping studies. Together with improvements in equipment, a software tool has been developed to reduce the number of tests necessary to optimise filtration technology and parameters for sizing.

Sep 13, 2010

By Harris J. W

The treatment plant at The Great Boulder Proprietary Gold Mines Limited was designed and erected by Chas. Ruwolt Proprietary Limited in 1934 to mill 12,000 short tons per month. The flow sheet called for fine grinding, straking, flotation, roasting of the flotation concentrates and cyanidation of the resulting calcine.In 1937 considerable alterations and additions were made to the plant. The grindin,g section was duplicated with addition of two 8 ft. x 6 ft. Abco Ball Mills to increase the throughput to 28,000 tons per month, and the flow sheet was changed from "straight flotation" to "precyanidation and flotation" neeessitating the addition of thickeners, agitators, Oliver filters and Edwards roasters.A further change to the flow sheet was made in 1942 with the introduction of sulphur dioxide conditioning ahead of the flotation section, to permit the treatment of 500,000 tons of oxidised ore. Since that date no major alterations were made to the flow sheet or equipment until 1950, when the modifications set out in this paper were commenced with the object of reducing costs and increasing plant efficiency.These modifications are dealt with under the section headings and are therefore not necessarily in chronological order.CRUSHING SECTIONThere has been no material alteration in this section although at the time of writing a 650 ton capacity ore bin is being erected ahead of the primary Jaques crusher. This bin will reduc'e the crushing time from a three shift to a two shift basis and reduce the labour force required by two men, giving an annual saving of £2,000.FINE GRINDING SECTIONAlterations to the grinding section were commenced in 1950. Prior to this date the grinding flow sheet calle...

Jan 1, 1955

By R J. Mills, B S. Sinclair, D A. Fergusson, A G. Goldstone

In 2005, Solid Energy New Zealand Limited obtained non-notified consent for the disposal of 1Mt of coal ash at the Rotowaro minesite, forming part of a coal supply agreement with the Huntly Power Station. The consenting of major mine site activities has historically required wide consultation and involves notification of the application.   The risk and cost associated with consultation can be significantly reduced via a non-notified process. A non-notified consenting process necessitates environmental effects to be shown to be æless than minorÆ, which requires the combination of robust science and a pragmatic approach to design, assessment of environmental effects, and consenting issues.   Key issues examined included consideration of how to practically operate a significant disposal project within the confines of an operating mine, minimising the costs, civil and geotechnical design and practical issues associated with traditional disposal. Environmental issues specifically related to the coal ash, led to a site specific performance driven approach to management rather than relying on conventional prescriptive approaches. Environmental issues of concern include the leaching of boron and aluminium from ash into groundwater and mine water management systems where both boron and aluminium can occur at elevated levels.   Coal ash exhibits unusual geochemical characteristics reflecting the primary coal composition and the combustion process. The dominant coal type combusted at the Huntly Power Station is derived from Rotowaro and the resulting ash is cementitious and has a high alkalinity. As a result the disposal design is based on the characteristics of the ash itself rather than the material into, or onto which the ash is disposed. Non-notified status was able to be achieved through consideration of these key characteristics of the ash, ensuring that the dimensions of the disposal site and each location was designed to minimise the flow of groundwater through the ash and demonstrating that the physical ash disposal effects are less than minor compared to the consented mining operation.

Jan 1, 2006