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Crocidolite deposits in the Hamersley Ranges, NW. of Western Australia, occur over a length of 180 miles and a width of 20' to 30 miles. Their stratigraphic environment and mineralogy is comparable to that of similar deposits of the Cape Belt, South Africa. It is probable that the known exposures' represent only a small portion of the total extent.Current production is wholly by Australian Blue Asbestos Pty. Ltd. at Wittenoom Gorge and has been in the order of 1,2,000 to 14,000 long t.p.a over the past six years.INTRODUCTIONThe Hamersley Ranges are located in the NW. Division of Western Australia and extend, approximately, from latitudes 21° 30' to 23°S and longitudes 117° to 1200 E. Their mean height above sea level is 2,000 ft, and they rise from 600 to 800 ft above the general level of the tableland which extends SE. from the coastal town of Roebourne.Mt. Bruce, the highest peak, is 4,024 ft above sea level. The ranges are intersected by numerous north-flowing streams, which are dry during the greater part of the year. These streams have carved deep gorges, and it is in these that the principal deposits of crocidolite outcrop.The presence of the mineral was first recorded in 1917, but the deposits remained untouched until 1937 when strong market demand for crocidolite resulted in considerable prospecting and mining activity, particularly in Yampire, Wittenoom and Dale's Gorges. It was established also that the blue asbestos belt extended from Willi Wolli Springs NW. to Millstream station, Le., over a length of 180 miles and a width of 20 to 30 miles. A number of attempts were made to develop and treat the Yampire and Wittenoom...

Jan 1, 1964

By P B. Hills

This paper discusses the computerisation of the drill hole database, some historical records and the creation of a three-dimensional model of the gold bearing structures for resource estimation and mine design at the Beaconsfield Gold Mine in northern Tasmania. The phase of the work reported here commenced in November 1997 and was completed in March 1998. The historical mining on the Tasmania Reef had reached a depth of 450 m below surface when work ceased in 1914. Production up to this time was 854 000 ounces gold. Recent activity has concentrated on testing depth extensions of the previously mined ore structure, to a depth of 1000 m below surface, and the establishment of an underground mining operation to exploit this resource. The lode structure at Beaconsfield is a typical mesothermal vein style deposit. Gold is contained within narrow quartz, carbonate and minor sulphide reefs or veins. Reef width is variable from a few centimetres to several metres with æsplitsÆ or bifurcations being common. The reef averages 2.7 m true width in the economic zones. The key feature of this style of mineralisation is that reef continuity can be confirmed by drilling to a high level of confidence, but the gold grades are somewhat more erratic in nature. The resource estimates were based entirely on drill data. The drill intercepts on the reef were coded for each split directly into a database and these allocations validated graphically. The distribution of grades and widths show an increasing gold grade with reef width for both the drill hole and historical data. The same histogram patterns, mixed populations and overall arithmetic average grade for the historical mine (at 21.52 g/t > 3 g/t Au) and new drill data (at 21.55 g/t > 3 g/t Au) would indicate that there has been no major change in the overall style or grade of the ore from the historically mined areas to the new resource. The reef, host geology, area of historical workings and resource zones at the Beaconsfield Mine were defined as a series of closed wireframes. The Tasmania Reef was modelled as five mutually exclusive wireframes, one each for the Main Reef, Footwall split, Second footwall split, Third footwall split and Hangingwall split. The data for this exercise was extracted directly from the drill hole database, stored in Microsoft Access format. The formation of the solids was largely automated with manual validation and refinements allowing for multiple runs using different interpolation methods and combinations of drill holes. A rotated 3D-block model in the plane of the Tasmania Reef was created to contain the grade model and allow for tonnage, grade and reef width estimates. An inverse distance squared (ID2) interpolation method was used with ranges of 25 m along strike and 125 m down plunge with blank areas infilled with 50 m by 250 m. Each reef split was filled separately using only drill intercepts from that split. The method was independently validated used MIK methods. Longitudinal sections have been prepared showing gold grade, reef width and width +grade. Estimates were also made for arsenic, sulphur and other minor elements. The long sections show three distinct mining zones. A method is presented for the conversion of the resources to reserves by the addition of mining parameters for minimum mining width, minimum pillar, cut-off grade and internal and external dilution. The selection is done on columns within the block model, and allows for all splits to be considered at once. Multiple runs can be made for varying combinations of parameters to test different mining methods and their impact on reserves, mine life and NPV.

Jan 1, 1999

TowerMill - Advantages in Wet Grinding Applications The TowerMill, which has now been in existence for no less than 50 years, is one alternative to the horizontal ball mill and offers several advantages. The TowerMill is widely used in (coal-fired) electric power plants for the grinding of raw material for the FGD (Flue Gas Desulphurisation) process involving very high throughputs, very fine product sizes and high availability. Some companies in the mining industry also looked at the use of such optimised grinding machines several years ago and found that many of the advantages offered in other industries are transferable to new applications. Much development work has been undertaken to improve the TowerMill for new applications and, as part of that work, tests have also been conducted to make direct comparisons of their performance with that of ball mills. Grinding tests were performed using the same raw materials and comparable machine sizes. Some of the results are discussed in this paper, along with a comparison of the advantages and disadvantages. The conclusion provides an outlook for some worthwhile future applications. The test results, which are described and analysed, show that the TowerMill offers significant advantages in relation to operating costs and operational safety. An example based on the wet grinding of limestone is presented.

Sep 13, 2010

By M C. Evans

"Mine decommissioning is the final phase in a mining project. Planning for decommissioning must commence for a proposed mine even before the government approves it. Queensland mining approvals require proponents to commit to completion (or closure) criteria defining successful rehabilitation. Queensland mining project statutory environmental authorities must also specify how progressive rehabilitation is to occur throughout the mining project. Final landforms with graded banks together with creek and run-off diversions are often required and constructed early in the life of a mining project. At closure, mining projects must demonstrate that future medium-term risks are not significant, or failing this, a residual risk financial payment must be made to the state. CSIRO climate change projections indicate that Queensland is likely to become warmer this century with less rainfall in parts and with extreme rainfall events likely to occur more frequently. This project was undertaken to?determine: if current rehabilitation planning tools assist in determining the environmental risks from mining closure not adequately addressing climate change if these risks are addressed by current rehabilitation outcomes.The north-west Queensland mining region and the central Queensland coalfields were represented in this project by five study sites. Local data sets for temperature, rainfall and rainfall intensity were produced using conservative greenhouse gas emission scenarios representing likely future atmospheres, and using the SimCLIM climate model, Evaporation data sets were also derived from available climate parameters. These projected climate variables supported equations and models used in Queensland to determine mining project rehabilitation completion criteria. Storm intensities and return intervals were directly applied to assess the likelihood of failure of engineered structures such as stormwater diversions and banks. Plant cover change determined by an existing growth model together with rainfall intensity and changes in the R and C factors of the universal soil loss equation (USLE) erosion model enabled estimates of long-term erosion rates. Flood estimates were undertaken using regional rated catchments.The study found that stormwater diversions and banks on recontoured rehabilitated landforms, if constructed to currently accepted completion criteria, would likely fail within 30 years and with the likelihood of failure steadily increasing thereafter. The change in likelihood of failure was able to be estimated and could be applied to the determination of residual environmental risk for approval of a surrender application involving rehabilitation. The USLE model showed that long-term erosion rates increased as a consequence of climate change from north to south across the Queensland mining precincts. Because the growth model did not consider carbon dioxide fertilisation affects, results would likely be worse-case.Likely climate change outcomes have consequential residual environmental risks of mining project rehabilitation failure. This increased risk may result in increased payments to the state from mining projects where high consequences exist. The liability to the state and risk to the environment can be avoided if today’s completion criteria address tomorrow’s climate change impacts.CITATION:Evans, M C, 2014. Queensland mines should consider climate change impacts for decommissioning, in Proceedings Life-of-Mine 2014, pp 535–562 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

The use of solid state detector and radioisotope x-ray source for x-ray fluorescence analysis is illustrated by analysis for iron, copper, zinc, tin, and lead in about 700 samples taken from Australian mineral process streams. Limits of detection based on counting statistics (3 standard deviations) range from 0·001 to 0·004 per cent by weight element. The analysis accuracy was usualIy between 2 to 10 per cent (rms) of the mean element concentration and was determined by comparison with assays supplied by mineral companies. In most cases the main cause of error appears to be due to this assay and not the x-ray fluorescence technique.Some potential fields of application of solid state detector and radioisotope x-ray source for analyses in the mineral industry are indicated.

Jan 1, 1974

By D A. McCallum

With depth, many gold ores become sulfidic with minerals such as pyrite, pyrrhotite and arsenopyrite becoming prevalent. In addition, many underground gold mines use tailings backfill to bind and store the waste. In these cases, acid mine drainage (AMD) can become an issue. One approach to the control of AMD is desulfurisation whereby the sulfide minerals are removed prior to disposal. Four sulfide tailings samples, representing different ore types and gold and base metal operations, were selected for assessment and testing using simple physical beneficiation techniques. The aim was to determine the extent to which mineral processing methods were suitable for separating sulfides from non-sulfides and for extracting potentially marketable by-products from the tailings. In order to streamline the testing procedure a simple diagnostic separation technique was developed to enable quick screening of bulk sulfide tailings for suitability for reprocessing. The testing procedure involved detailed characterisation and a sequential set of testing regimes based on simple unit processes including water washing, classification, gravity concentration, magnetic separation and bulk flotation. The preliminary test results indicate each unit process can play an important part in producing effective sulfide/non-sulfide separations and in generating useful by-products from the tailings. Potential valuable products identified include coarse, benign silica sands, bulk iron sulfide products rich in pyrite and/or pyrrhotite, high-grade iron products (magnetite) low in silica, low-volume bulk sulfide concentrates and low-grade molybdenite and talc products. The work presented shows how sulfide tailings can be viewed as a resource rather than a waste stream, and identifies a pathway for developing a more sustainable approach to the environmental management of sulfide tailings for the future.

Jan 1, 2007

IF a straight line should be drawn on the map (See 1, page 96) through the northern half of the South Island of New Zealand, from Mt. Domett in the north to Arthur's Pass in the south, and another line drawn parallel to it and at a distance of ten miles to the west, according to the topographic scale, it will be found that within the belt thus drawn across the country all the most important mines, past and present, of the South Island are situated, with the exception of a few in Otago.The most important product of this tract being gold, and Reefton, the most important southern mining field, being situated at about its central portion, the zone may aptly be termed "The Great Reefton Gold Belt." The occurrence of so many gold mines along this particular strip of country is not at all a matter of chance, but is the outcome of cause and effect. Running along the eastern side of the gold belt are the Brunner and Victoria Ranges, which are chiefly composed of crystalline schists and metamorphic granite of probably Cambrian or Silurian age; between these and the gold-bearing series there are interposed at one or two places some beds of slates, limestones, and...

Jan 1, 1910

The growth of "Unit Load-cargo handling technology in world cargo lin- er trades over the last decade has cre- ated a situation in which special pur- pose-vessels (cellular container ships, roll-on/roll-off vehicle deck ships and Lash type vessels) are rapidly replac- ing conventional cargo ships, the principal means previously available for transporting heavy lifts. Consequently heavy lift traffic has tended to accumulate awaiting ship- ment, especially where discharge is required in "off beat" locations. A partial solution to this problem will be provided by new and small but exceptionally versatile ocean going heavy lift carriers now finding their way into world trade routes. These new ships combine extremely high lifting capacity, high manoeuvreability and exceptionally shallow draft with bow and stern Ro/Ro capability. They can handle rolling loads of exceptional size and weighing up to 1,000 tons Each. But the problem is a far larger and more serious but essentially a domestic one. Major industrial pro- jects in Australia will require pro- gressively heavier and larger plant and construction sites are becoming much more inaccessible. Whereas these new ocean going heavy lift carriers have ample capacity to satisfy part of the total transport requirement, there is clear evidence to show that domestic transport resources have little if any potential for increase in capability at the same rate as demand or at the same rate as sea transport facilities. Resolution of the larger problem is within reach but only through a pro- perly co-ordinated approach to future planning for the overall needs of large scale projects on a national basis. This co-ordinated approach must involve Federal and State government transport administrators, railway and highway authorities, shipping and road haulage interests and finally the planners of the projects which require these improved heavy haulage services.

Jan 1, 1973

By A T. Spathis, K E. Leslie, K R. Blay

Many open pit mining operations seek to control blasting-related movement of ore and waste to minimise loss and dilution. Tracking the movement of ore boundaries can result in the maximisation of ore recovery and minimisation of waste sent to the mill, thereby optimising the economic performance of the operation.A novel solution for tracking the ore–waste boundary location before and after a blast uses subsurface markers placed along the boundary with all measurements and scans conducted remotely from the blast block. Upon system activation, user-operated equipment on the surface determines the three-dimensional (3D) location of the subsurface markers.The patented system concept combines two electromagnetic mechanisms, magnetic positioning and radio frequency through-rock communications to enable remote battery-powered markers, buried within the rock to be accurately located in 3D space.Field trials at a quarry have demonstrated the system can comfortably handle over 100 subsurface markers with a complete scan, including set-up, taking less than an hour. Location accuracy for each marker in 3D space is better than 0.5 m at a range up to 50 m from the magnetic source, and the system has an overall operational range in excess of 75 m.CITATION:Blay, K R, Spathis, A T and Leslie, K E, 2015. A remote, rapid and accurate three-dimensional ore waste boundary tracking system, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 297–306 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

The prime objective of geometallurgy is to improve the profitability of mines through the use of spatial models of rock properties that have a significant impact on value. Although a key property is the grade of the component of interest, because it directly influences the revenue from saleable material, increasingly attention is being focused on other attributes. These 'non-grade' variables may have a less direct, but equally profound impact on value, either by reducing potential revenue (eg lowering recovery, deleterious elements, etc) or increasing mining or treatment costs (eg comminution, grindability, throughput, reagent use, etc). Collectively, these variables have been described as 'geometallurgical'. There are three main areas of activity required to realise the value of geometallurgy: 1. acquisition of appropriate data through sampling and measurement, 2. building spatial models of geometallurgical variables, and 3. using these models to optimise value. Each of these is built on the foundation of the preceding step. In building reliable spatial models, it is critical that the amount of error introduced to data by the sampling and measurement processes is understood and quantified, in order that the inherent variability of the component of interest can also be properly understood. Management of the quality of grade variables is now applied (with different levels of diligence and success) across nearly all sectors of the mining industry, not least because of the necessity to adhere to Codes of practice (eg JORC, 2004). The necessity for quality management and at least the broad framework of what to do in practice is reasonably understood by many relevant professionals. There are also a number of tools, including software products, statistical analyses and presentation formats, available for those managing grade data. It is also abundantly clear, that in many cases people have little understanding of why they are doing particular quality control activities, or how to sensibly interpret the results. The same is not true for many geometallurgical variables. In almost all instances the authors have seen, the magnitude of sampling and analytical/measurement error variance embedded in geometallurgical test data is untested and unknown. This is partly because until relatively recently, metallurgical data has mainly been collected for the purpose of process and mill design, with few, expensive tests carried out on 'average' samples of the orebody. Increasingly however, there is a move towards collection of much larger data sets from spatially distributed sampling, and thus a growing necessity to understand the errors inherent in both sampling and analysis of these types of variables, and how to manage them. In order to understand how the quality management practices applied to grade variables can be extended to geometallurgical variables, it is essential to understand the theoretical foundation that supports these practices. This requires an analysis of the concepts that underpin the 'principles of additivity' (Matheron, 1963), the 'theory of sampling' (Gy, 1982, Pitard, 1993), and 'statistical process control' (Shewhart, 1930). Relevant concepts are then integrated to form a foundation to develop methods to improve the quality management of geometallurgical variables. Application of this framework will significantly increase the integrity of geometallurgical data, the reliability of geometallurgical models and ultimately the value derived from implementing geometallurgy. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Mar 1, 2010

By S M. Jowitt, G M. Mudd

"The mining industry is the source for the vast majority of the metal, mineral and energy resources we use on a daily basis. New deposits are discovered over time and are developed into mines before being rehabilitated – a sequence that when repeated can help contribute to the noble notion of ‘sustainable development’, despite the generic concept of mining being the unsustainable consumption of non-renewable resources. The scale of the modern mining industry is immense – from iron ore and coal to base and precious metals, modern mines are sometimes hundreds or thousands of times bigger than their long lost historic ancestors. We also live in a world with emerging and increasing demands for so-called technology metals (aka ‘critical’, ‘e-tech’ or ‘specialty’ metals) that are needed to feed the rapid growth in renewable energy (especially solar photovoltaic panels and wind turbines), consumer electronics, sophisticated military technologies and super alloys, amongst other uses. These elements include the rare earth elements, indium, germanium, tellurium, rhenium, selenium, gallium and many others, most of which had few or no known uses in the recent past. Although the mining industry has been successful in developing ever larger mines and increasing the scale of production, the key issues underlying the future of the industry are declining ore grades, increased tailings and waste rock generation, the presence of toxic or other impurities, balancing the economics of primary and secondary products, stricter environmental conditions, more difficult exploration, increasing community expectations, as well as the processing of more complex or refractory ores, let alone the recent volatility in world commodity markets. Here, we synthesise our recent research on many of these various issues, focusing on the need to link all areas within the mining chain from mineral resources through mining to environmental performance in order to ensure we obtain the most out of our modern mining effort. The paper presents a unique and detailed assessment of the sustainability challenges and opportunities facing modern mining – and geometallurgical thinking is at the heart of this conundrum.CITATION:Mudd, G M, Jowitt, S M, 2016. From Mineral Resources to Sustainable Mining – the Key Trends to Unlock the Holy Grail?, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 37–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By M Rafty, A Markham, S Atkinson, M Heyting

Over recent years there has been a significant increase in the number of miners in the Pilbara region of Western Australia targeting channel iron deposits (CID) located in valleys, intersected by ephemeral creeks and below the groundwater table. The falling iron ore price has triggered a drive to reduce cost and maximise yield. Creek diversions provide an opportunity to maximise the utilisation of orebodies and extend the life-of-mine.Creek diversions that are required during mining operations to access ore and provide flood protection have historically been constructed as uniform engineered channels designed primarily for flow conveyance while minimising earthworks costs; however, the design of diversions becomes more complex when they are required to function in a similar way to the existing creek system during operations and remain stable during more extreme events than would typically occur following mine closure, in accordance with current regulatory guidance. The design specifications for closure are often more rigorous than the operational phase, and could incur significant additional cost to implement retrospectively if not planned and designed upfront.The complexity of diversion design depends on site specific factors such as: the size of the creek to be diverted; hydrology; corridor restrictions; geomorphology; hydrogeology; geology; environmental and heritage values; potential impacts and the risk to operations and environment. The complex interactions of these factors must be well understood and hydraulic modelling undertaken to characterise the existing creek system, demonstrate the diversions, provide adequate flood protection during operations, and can function in a similar way to the existing system following mine closure. This paper presents key design considerations for Pilbara creek diversions, operational and closure requirements, mine planning considerations, risks, cost saving opportunities, and the benefits of an integrated approach to design.CITATION:S Atkinson, A Markham, M Rafty and M Heyting, 2017. ‘Back to the future’ – resilience in historical context and implications for the future, in Proceedings Iron Ore 2017, pp 367–374 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By D M. Aranha, M A. Fonseca, M Echtern

The regional syndeformational metamorphism affecting the Itabira Iron Formation (IIF) at Quadrilßtero Ferrffero (QF) was formerly discussed by Dorr (1965), who proposed that quartz grain size could monitor the metamorphism, according to James (1955), and that the formation of haematite could be the result of the synchronous metasomatic process. Herz (1979) suggested the existence of three metamorphic zones, not mentioning the haematite formation. It could be observed that the primary oxide phase in the IIF is magnetite and most of the hard haematite was derived from the metamorphic replacement of magnetite, forming micaceous or schistose haematite. Differently from most iron formations in the world, the formation of haematite deposits at QF occurred under high oxygen fugacity during metamorphism. The haematite microlaths display a strong preferred orientation, which determines the alongated shapes of the fragments. The terms foliated and unfoliated haematite have been applied by Dorr to the micaceous or schistose haematite, and to the isotropic, hydrothermally derived haematite. Under the microcope, the haematite exhibits a strong crystallographic or lattice orientation encircling the magnetite and martite porphyroclasts. The strain rate determined and defined the textural variation, size and economic importance of the deposits and the ore grade. Metamorphism at QF increases eastward and resulted in the formation of a gruneritic Fe-Mg amphibole, at the western portion, followed by a cummingtonitic amphibole at the central-western part, succeeded by the actinolite zone at the central-eastern part, and finally to the tremolite-anthophyllite zone to the east. These zones, arranged in a north-south pattern, can be followed in the pelitic units, whereas appear sericite-chlorite, kyanite-chloritoid and garnet-staurolite respectively. Carbonate geothermometry in IIF also may support the metamorphic variations. At the western zone the haematite forms small lenses within the itabirite, P-contents are slightly higher than in the remaining IIF, haematite grain size is minute, resulting in a submicaceous texture and the amount and dimension of relict magnetite within haematite is greater than in the other parts of QF. Jangada and Serra Azul deposits are examples of this zone. The central-western zone is characterised by significant haematite deposits, in considerable quantity and size, haematite grain size increased, in order to produce a micaceous texture, the P-contents and the amount of magnetite decreased. Pico do Itabirito, Cappo Xavier, Capitpo do Mato and Tamanduß correspond to the deposit type of this zone. At the eastern-central portion the amount of the hard haematite deposits decreases, increasing the soft haematite ore due to higher strain rates. However, it can be perceived that the relict magnetite almost disappeared and the haematite grain size became coarser than the haematite from the western zones. At the eastern zone, the haematite deposits exhibit typical schistose texture, the magnetite porphyroclasts are absent and the lowest P-grades in the haematitic iron formation. The haematite bodies characteristic from this zone are Andrade, Morro Agudo and the deposits at the Itabira District. The hydrothermally derived compact and isotropic haematite deposits, formed subsequently to the micaceous haematite bodies, were generated after deformation ceased, but under very high fluid pressure. The metamorphic reactions magnetite + quartz + H2O = grunerite + haematite and magnetite + quartz + H2O = grunerite + O2 were decisive in the formation of the metamorphic haematite deposits.

Jan 1, 2007

By P Knights

This paper examines the process and specialised skills required to extract insight from data routinely collected by mine operations, maintenance, engineering and environmental departments. Typical insights include: enhanced understanding of root causes; recommendations for next best actions; and simulation of likely scenarios. The skills required for advanced analytics are not currently the domain of mining engineers. The professions required by tomorrow’s mines are likely to be diverse and multi-disciplinary, and will include control engineers, software engineers, mathematicians and statisticians. A case study is presented that correlates mobile equipment production delays with rainfall events across three mines on the east coast of Australia. One mine is shown to have significantly more rain related downtime than the other mines, providing compelling evidence to improve productive performance.

Nov 22, 2011

For its Hellyer project, Aberfoyle sought to establish a high degree of confidence in all aspects of the feasibility study. Accurate capital and operating cost estimates were an integral and essential part of the study. They were crucial to the evaluation of investment returns and competitive cost position. Both the capital and operating cost estimates were based on the comprehensive data available from exploratory mine development, pilot plant operation, detailed engineering design, and Aberfoyle's experience in the area. One of the principal project objectives was to maximise operating productivity and efficiencies and this created capital cost alternatives which needed thorough cost-benefit assessment. The estimated capital cost for construction and development was $90 million, and the project was completed virtually on time for $80 million. The first year's experience indicated that operating costs would settle to well within 10% of the estimates.

Jan 1, 1990

Local conditions at Hatches Creek are described, together with the mineralogy, mining and treatment of tungsten ores, with particular reference to procedures adopted by Pimer Mines, N.L.The Hatches Creek tungsten field covers an area of about 20 square miles in: Central Australia; 285 miles' N.E. of Alice Springs. Access is by rail to Alice Springs, then by 200 miles of bitumen highway to Barlo Creek and 8,5, miles of bush track to the field. Passengers can also reach the mines by... A semi-desert climate prevails Rain; generally in the form of thunderstorms falls in the summer months: December to March. Average annual rainfall is approximately 15 inches but there is great variation from year to year, occasional droughts being followed by torrential downpours. Vegetation is sparse except in the wide creek beds. Surface water occurs in rock holes some of which, spaced miles apart, carry permanent water...

Jan 1, 1955

By Tyler R. J

Methylene blue dye adsorbs on chalcopyrite concentrates slurried in aqueous solution. Saturation adsorption can be achieved within about 24 hours for dye equilibrium concentrations greater than about 10-5 M. The dsorption coverage is obtained from a measurement of the' colour change of the solution. Comparison with BET measurement of the concentrate surface area shows that 2.4 ± 0.1 µmol of methylene blue are adsorbed per square metre of surface accessible to the dye cation. The procedure described can be used as a single-point measurement and values for the surface area can be otained to within about 10 per cent with inexpensive instrumentation.

Jan 1, 1979

THE art of mine surveying has made very great progress in recent years, and is still advancing, perhaps faster than any other branch of surveying. The scope of the mine surveyor's duties has greatly increased, his instruments and methods have improved, the responsibility of his position is greater, and the end is not yet in sight.It might be supposed that such a steadily growing subject would have an adequate literature, but this is by no means the case and outsiders commonly judge mine surveyors by their text-books. Hardly any condemnation can be too strong for most of these books. The English books truckle to the antiquated and crude methods apparently still in use in England, and thereby largely aid in perpetuating them; they commonly in illustrative examples give the distances in fathoms, feet, and inches; they spend page after page discoursing on instruments that should have been forgotten long ago; they try to antagonize theory and practice by detailing such calculations as that a certain vein will contain 2,003.907 pounds of galena per square fathom, and then reduce this amazing quantity to hundredweights, quarters, and pounds. Nothing can be more unscientific, or, for that matter, less businesslike, than unwarranted assumptions of accuracy; it is, perhaps, the greatest curse of applied science. Here we have a calculation to thethousandth part of a pound, when there is probably an unavoidable error of two hundred pounds. What shall we say of a man who explains how to measure the depths of shafts to the hundredth part of an inch by means of short brass rods screwed together...

Jan 1, 1909

Evaluation of Comminution Circuit Design for Sustainability Using EcoNomicsTM

Sep 13, 2010

Urban development to the south of Sydney is approaching areas of current and proposed coal mining. Already some structures and residential areas are affected by mining subsidence.Subsidence resulting from either conventional pillar extraction methods or longwall mining has been monitored for 15 years to enable the characteristics of the surface deformation to be determined.The vertical and horizontal displacements of survey stations on the surface are monitored and the results arc used to calculate subsidence, changes in slope of the surface, curvatures along the subsidence profile, and the ensile and compressive strains. These features are in turn related to the underground extraction to give a description of surface subsidence and the development of subsidence with time.Subsidence investigations have been carried out over all or part of the workings of six collieries in the Southern Coalfield.Two case histories illustrate the procedure in the investigation of subsidence phenomena. The first example is the study of the subsidence over a series of longwall panels in one seam and the second is a study of subsidence over pillar extraction in two seams one above the other. From the results of the investigations the effects of panel widths on subsidence are determined.This and other information assists mine planning in areas where surface movement and deformation are important considerations.

Jan 1, 1980