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By Alvin J. F

Tin in ores containing 0·025 to 1·5 per cent tin can be determined polarographically by the reduction of the chlorostannite ion at the dropping mercury electrode in 2M hydrochloric acid solution containing 15 per cent ammonium chloride. The tin is separated from interfering elements by distillation as the tetrabromide and collected from the distillate by co-precipitation with aluminium hydroxide. The method can detect 0·01 per cent tin in ore.INTRODUCTIONAn iodimetric method, suitable for routine analysis of titrating tin in concentrations down to 1 per cent, has been available for some years (Low, Weinig, and Schoder, 1939).As concentrations fall below 1 per cent tin, there is increasing difficulty in obtaining a distinct end point due to large amounts of iron and silica normally present after fusion of the ore. Since concentrations of tin down to 0·02 per cent are significant in ore dressing products it was necessary to examine methods to determine such low concentrations, and to adapt these to tin ores containing a wide variety of other minerals.EXPERIMENTALDigestion and separationCassiterite, the principal tin mineral, is refractory but readily attacked by a sodium peroxide flux to yield soluble sodium stannate. In a recognized procedure, a sample of ore is mixed with up to 15 g of sodium peroxide in an iron crucible and swirled over the full heat of a Meker burner for 7 min. The fusion is leached with water and acidified.This solution then contains tin, silica, and other soluble...

Jan 1, 1962

A recoverable uranium resource, shown to be suitable for in situ leaching, was discovered at Honeymoon in South Australia in 1971. Exploration of the deposit was carried out during the period from 1973 to 1979. Uranium mineralisation occurs in a coarse-grained unconsolidated sand aquifer located in the Yarramba Palaeochannel at a depth of approximately 110 m. Following initial development during 1979 to 1983 and the construction of demonstration leach facilities, the Project was put on hold. Southern Cross Resources purchased the Project in 1997. Government approval was received in March 1998 for the operation of on-site demonstration leach and recovery facilities while an Environmental Impact Statement was prepared and a 1000 tpa commercial production plant was designed. The Environmental Impact Statement (EIS) was released in June 2000 and operation of the test facility was completed in August 2000. Acceptance of the EIS by Commonwealth and South Australian state governments was announced on 20 November 2001. A Mining Lease was granted over the area of the proposed ISL operation on 8 February 2002. Operation of the Project is entirely dependent on using highly saline underground water resources to supply process and human needs. The management of discharge streams from the plant by re-injection was approved. The Honeymoon demonstration plant was the first adaptation of the solvent extraction process to highly saline in situ leach solutions. As such, it incorporated a number of unique operating and installation features. The trial period enabled optimisation of the process chemistry, additives and management and serves as an invaluable base for the proposed plant design and future operation. This paper discusses the nature of the uranium occurrence, the effect of saline water on the leach process and equipment, project design and environmental considerations, the requirements for disposal of discharge streams to minimise the impact on the arid environment and the requirements for rehabilitation following project completion.

Jan 1, 2002

During the course of the major research in the Metallurgy Department of the University of Melbourne into the creep characteristics of lead and .its dilute alloys, it has been the practice to prepare the majority of test specimens from rolled strip. From time to time during the progress of the work, certain variables involved in. the rolling of the experimental ingots have been investigated. It is proposed to collect together in this paper the results of these experiments. Some general features relating to the type of deformation produced have been discussed in a previous paper.While it is admitted that the conditions prevailing through this work differ' in some respects from those of industrial rolling practice, it is felt that many of the factors investigated have an important practical significance. Some of the work described forms a continuation of the researches of R. S. Russell (2) , (3) , (4), into the recrystallization of various pure leads after deformation by rolling.MATERIALS USEDIn this work, a variety of "pure" leads and certain dilute alloys made from the purest of the basis leads have been studied. The compositions of the basis leads and the corres...

Jan 1, 1940

By Blaisdell J. L, MacPherson G

The present communication records the results of a research investigation conducted in the Porcupine Gold Mines in Timmins, Onto. Soon after silicosis became a compansable disease in Ontario under the Workmen's Compensation Act in 1926, the attention of mine operators and physicians was drawn sharply to the prevalence and importance of this condition in the mining industry. A number of examining centres were established in Northern Ontario by the Workmen's Compensation Board, and the yearly X-ray examination of miners was made compulsory.Although working conditions were soon improved, the mining industry realized that they were confronted by a problem demanding basic research for its final solution. The late Sir Frederick Banting had, for a number of years, been interested in silicosis, and it was upon his suggestion that an experimental investigation was undertaken at the McIntyre-Porcupine Mines Ltd., Schumacher, Ont., in November, 1932. A preliminary report of this investigation was published in 1937 by Denny, Robson and Irwin and a further report by the same authors in 1939.Accepting the theory that silica exerts its injurious effect upon animal tissue through a slow transformation into silicic acid in the presence of body fluids; these authors assumed that if the solubility of the silicious material retained in the lung could be sufficiently reduced, the usual fibrotic response would be modified or would not occur. A search was therefore undertaken for some non-toxic compound that would fulfil this purpose. After investigating ma:qy substances, Denny and Robson discovered in 1936 that the presence of small amounts of aluminum powder almost completely inhibited the solubility of silicious material in vitro. An intensive study of the mechanism involved later showed that the reduction in solubility was due chiefly to a coating of the silica particle with a thin film of a gelatinous hydrated alumina which on drying formed the crystalline alpha aluminum monohydrate boehmite (AI203.H20). The presence of this absorbed layer on the surface of the quartz was indicated by -staining it with aurin (ammonium salt of aurin tricarboxylic acid) and proved by Germer and Storks by means of electron diffraction patterns.Inhalation experiments with animals were at once begun, using pure quartz dust with and without aluminum powder. (See original communications.) These observers showed that while typical silicosis was produced in about 5 months in the control animals receiving silica dust alone, the...

Jan 1, 1945

The GPS and information technology industries are now applying considerable development effort to what is being termed machine control and machine information systems, in particular focusing on the industries the of mining construction and agriculture. GPS based systems are demonstrably finding common acceptance and adding commercial value to many machine applications in industry. This has been the first step in the evolution of the information age that is now reforming mining practices. Adding the technologies of wireless data communication, modem computer databases, and networked PC's mining is on the verge of a new era in overall process management. This paper is a general discussion of what the information age means to miners and a general description of new mining operation technologies available to day from the Caterpillar technology alliance.

Jan 1, 1999

By J C. Waters

Pseudoclastic hydrothermal alteration textures occur within quenched coherent dykes forming part of a subaqueous dome complex (~4 Ma) onPonza Island, Italy. These textures are similar to those observed in considerably older (~500 Ma) subaqueous volcanic rocks at a number of localities throughout the Mount Read Volcanics in Tasmania and elsewhere in ancient volcanic sequences of this type in Australia. This is significant because the processes of formation, hydrothermal alteration and secondary mineralisation of ancient volcanic sequences may be better understood if we can make comparisons with modern analogues. Observations at Ponza imply that these pseudoclastic alteration features form synvolcanically or immediately after dyke emplacement and lava extrusion. This is compatible with scenarios presented for their formation in ancient sequences in the Mount Read Volcanics, Tasmania.

Jan 1, 1995

By Poi G, Madgwick J. C, Davis P, Pannowitz D, Cho D, MacKay B, Chan S. M, Varga R. A, Chun U

Periodic dilute sulphuric acid treatment ofstill, batch-fed, molassesenriched, microaerobic, manganese-dioxide-Ieaching microbial cultures led to marked improvements over untreated cultures. Percentage Mn++ recoveries increased (7X), rate of Mn++ formation improved (3X) and yields of Mn++ per molasses use were more economical (5 X). The yield in terms of molasses used improved with decreasing sugar used (eg 1.17 g Mn++/gram molasses at 0.2 per cent molasses (w/v) feed and 24 per cent (w/v) pulp density MnO2 tailings). The most effective Mn++ leaching in terms ofpercentage recovery (97 per cent) and rate ofleaching (46 mg Mn++/day) was at 0.5 per cent molasses (w/v) and 14 per cent pulp density (w/v) MnO2 tailings.

Jan 1, 1986

By P J. White, J V. Lawless

Low-sulphidation epithermal gold deposits, which form in quasi-hydrostatic convective hydrothermal systems, frequently contain chalcedony within high-grade ore, which has been interpreted to be a crystallisation product of amorphous silica. To deposit amorphous silica rather than another silica polymorph at elevated temperatures requires very high silica concentrations, because of its relatively high solubility. Only extreme boiling caused by decompression followed by wall rock heating upon structural dilation, can achieve this. As gold deposits with amorphous silica it must be produced by the same mechanism, particularly since extreme boiling is also a very effective mechanism for gold deposition. Recent developments support this view; the first is the detailed isotopic analysis of chalcedony-bearing high-grade veins reported from Hishikari, Japan, in which oxygen isotope results are indicative of extreme boiling and hydrogen isotopes indicate initial deposition of amorphous silica. The second is the finding of chalcedony within geothermal pipe work in the Rotokawa geothermal field in New Zealand. Rotokawa is a comparatively hot field (335¦C at depth); hence separation of the steam-water mixture produced by the wells is undertaken at a comparatively high temperature (220¦C) to minimise down-stream silica scaling. Even so, silica scale, some of which is chalcedony, does occur, under similar conditions to that in low-sulphidation epithermal deposits. Evidence of chalcedony forming under these conditions, reinforces the interpretation that decompressive boiling is the main deposition mechanism for gold in low-sulphidation epithermal deposits. It is possible that there is sufficient drop in temperature due to decompression that, at least initially, the silica deposits directly as chalcedony. Low-sulphidation epithermal gold deposits that do not contain chalcedony, such as those in the Philippines, may form at temperatures too high for chalcedony to directly form. The recognition of decompressive boiling as the main deposition mechanism in low-sulphidation epithermal deposits means that exploration can focus on zones where this has taken place by combining paleohydrological reconstruction and structural geology.

Jan 1, 2002

By Yindong Yang

Despite the importance and usefulness of basicity in metallurgical slags, the optimum quantitative expression of it has remained elusive, partly due to the fact that the precise concept of basicity has not been properly clarified. The two basic approaches to the concept of basicity are the Lux-Flood, which perceives basicity in terms of the activity of the free oxide ion, a O2- , and the Lewis, which perceives basicity in terms of the ability to donate negative charge. The former has been almost universally adopted in the area of metallurgical slags, while the latter has been increasingly accepted in the field of glass chemistry. In this paper, some difficulties of the Lux-Flood approach are pointed out, including the need for indirect measures of a O2- , which have proliferated in recent years. Accordingly, it is suggested that the Lewis approach has a good deal to commend it, and that the quantification of it in terms of optical basicity is the best measure of basicity available, which should therefore be more widely applied in metallurgical slags than it currently is. The fact that there are intrinsic problems in evaluating the optical basicities for the transition metal oxides is acknowledged, and a new scale is recommended. The patterns of iso-optical basicity lines in ternary systems are shown to agree well with the pattern of iso-activity and iso-capacity lines under appropriate conditions. * Originally published in the Proceedings of MINPREX 2000, published by The AusIMM.

Jan 1, 2001

Mineral Changes that Occur During Coal Gasification

Sep 13, 2010

A key driver to the success of a tunnelling project (the project) is the management of hydrogeological risk. The hydrogeological risk, if not managed, may cause significant impacts on the overall performance of the project. Impacts may include groundwater quality impairment due to contaminant transport and acid drainage from disturbed geology to groundwater, and groundwater lowering. The groundwater lowering and quality impairment may cause tunnel failure, with consequences such as injury to humans, as well as reduced property and environmental values, potentially costing millions of dollars to sponsors of the project. Depending on the nature of the contaminants and level of hydraulic connection of bedrock fracture along the length of tunnel, the contaminant transport may reduce structural strength of the tunnel due to corrosive action of contaminants such as acid drainage. The groundwater lowering can lead to varying degrees of ground settlement, posing threat of tunnel collapse. The management of hydrogeological risk includes:detection of potential pathways for contaminants into and around the tunnel,identification of factors responsible for the lowering of groundwater, and development of strategic measures to control groundwater lowering and contaminant transport. The paper presents an in-house hydrogeological risk management model named Vedanta-THRM (tunnel hydrogeological risk management). The model uses Risk Management Standard AS/NZS 4360:2004 (Standards Australia, 2004), Pressure State Response framework developed by Organisation of Economic Cooperation and Development, and Interaction Matrices. The Vedanta-THRM identifies important characteristics, processes and events of potential hydrogeological risk and develops control measures for managing hydrogeological risk throughout the life cycle of the project. The Vedanta-THRM was applied for a project in the early stages of planning and found to be useful in assessing, evaluating and reducing the hydrogeological risk in a managed approach that potentially increased the performance of the project. The application results also provided management options for use by project sponsors and insurance industry, which included tunnel risk financing options and options for equity investors to choose among various returns under different tunnel credit ratings.

Jan 1, 2008

By Belcher C. B

A procedure was required for the rapid determination of silicon in low-alloy irons and a suitable method used the formation and reduction of silicomolybdic acid at 50°C. The procedure gives results for elemental silicon and this enables the correct computation of oxidation requirements in basic oxygen steelmaking. The method could be useful in iron foundries which have not installed direct reading spectrometers.INTRODUCTIONOxygen steelmaking experiments required rapid determinations of 0,5-1,6 per cent silicon in iron (3-4 per cent C) within 10 min of sampling; a reproducibility better than ±0.03 per cent Si was desired. Only elemental silicon (Si°) is of interest as a fuel in basic oxygen steelmaking technology, and the proposed procedure determines exclusively this form of silicon. The method is described as it may prove useful to other workers although the interference study would be incomplete for some applications.The analysis of silicon in iron is frequently obtained using direct reading spectrometers, but for the proposed experiments the spectrometers could not be used because of the prohibitive distance from the furnace. It should be noted that spectrometers determine both the elemental silicon and that present as silicon dioxide in occluded slag and inclusions.The silicon content of iron and steel is determined in this laboratory by spectrophotometric measurement of a "molybdenum blue" colour. The reactions involved have been extensively investigated; Strickland (1952) showed that a...

Jan 1, 1965

By B Bamford

High speed diamond cutting has extensive applications in civil and mining engineering. A project involving the diamond sawing of black granite is investigating the nature of the diamond cutting process. A sawing machine was devised to adjust the cutting load and measure cutting speed. Cuttings were collected for size distribution analysis. The surface produced by interaction between diamond. grits and the rock was subjected to microscopic investigation. Increasing load prompts the proportional increase in the cutting rate. But the mean size of cuttings shows little change. The photomicrographs of the cutting tracks indicate neither patterns of crack formation nor signs of the ductile behaviour of the rock. A diamond cutting model for hard rock is formulated on these observations. Diamond cutting is a process of surface failure, which advances in four stages. The polycrystalline characteristics of a hard rock and the action of high-speed diamond grits guarantee the creation of crack nuclei which develop into cracks in various directions. This network crisscrossing cracks enable the stripping of this surface layer from the rock.

Jan 1, 1992

By J de Witte

When used in suitable ground conditions, rock bolts can have advantages over other permanent tunnel lining solutions. Permanent rock bolts offer flexibility in tunnelling profile and rapid rock bolt installation can enable time and cost savings. There are also disadvantages when considering the suitability of rock bolts for permanent support installations. These generally concern achieving the specified durability requirement over the specified design life. By investigating alternate approaches to rock bolt installation, quality assurance (QA), monitoring and design life it may be possible to alleviate some of these concerns.The design and construction benefits that can be realised through the use of rock bolts are primarily related to reducing project program time. This time reduction could be realised if rock bolts are considered as a permanent solution, with the installation being completed as a part of the primary excavation cycle. Any reduction of the program could allow direct and indirect cost savings and in the case of a major project, allow the revenue stream to be realised earlier.Currently ambiguity exists where the treatment of rock bolts as permanent support components is inconsistent with that of (often identical) ground anchors, as utilised in stabilising cut and cover structures. The ground support design process, implementation and testing are generally similar, though the acceptance of rock bolts as long-term support elements is treated differently to ground anchors in technical specifications.This paper discusses some of the benefits available through the use of rock bolts. It offers different solutions to the concerns surrounding durability, including alternate approaches to installation, Quality Assurance practices and monitoring solutions. The selection of an alternate design life is also investigated as another means of alleviating concerns around long-term durability. The paper will also provide an indication of savings that could be expected through the use of rock bolts as part of a long-term support system.

Mar 8, 2011

By J Say, M Hawtin, L Carlon, P Cann

Historically, production from sublevels of the Ernest Henry Mine (EHM) started from blind uphole rises at the end of slot drives. Where previous investigations considered removing these slot drives and starting production with independent ore drives, any development savings were consumed when drives were extended to minimise ore loss. Since 2017, EHM and Orica have been investigating opportunities to optimise drill and blast practices by implementing Orica’s Wireless Electronic Blasting System (WEBS). To reduce ore drive development metres, a novel design was proposed utilising the WebGen™ 100 system to combine a rise with pre-charged widening firings. Initially these new rise and widening firings achieved results similar to previous EHM designs, achieving on average 81 per cent of design height and width. Due to poor performance of the fourth trial a significant re-design was required. Modifications included drill hole re-positioning, in-hole primer relocation and initiation delay adjustments. Since the re-design a step change in rise performance has been observed with rise and pre-charged widening shots averaging 95 per cent of design height and width. With rise and widening performance exceeding expectations, the removal of slot drives has allowed a substantial reduction in lateral development. Development savings of 165 m and 169 m from the RL1325 and RL1300 levels have been achieved. Primary draw and ore recovery has also increased due to the later addition of pre charged forward stripping rings. Level design changes have also significantly improved the mining cycle by allowing for a reduction in required ground support, improved secondary ventilation, a reduction of critical path development, simpler production scheduling and less wear and tear on machinery. Future mine level designs now incorporate key learnings and are proving beneficial to a variety of scenarios including changing orebody boundaries at depth.

Mar 15, 2021

By S O. Hille

Modern remote mining operations in Australia are more commonly trending towards fly-in/fly-out (FIFO) sites. This trend is driven by numerous factors including increased business centralisation, reduction in operating costs, and a desire to live in coastal cities that offer closer family networks and a greater diversity of facilities. Consequently, the resource development industry has had to adapt. When WMCÆs Mount Keith Nickel Operation commenced operations in 1994, it was developed as FIFO for its entire workforce. Since then, there have been several permutations of rosters within a 21 day compressed work cycle including the 14/7 cycle. This paper discusses a case study of the change in management process to the 9/5 work cycle focusing on minimising fatigue in the workplace. It includes the discussion of the business case, employee reaction and the practical application. The impact of the best practice change after 18 months is discussed.

Jan 1, 2002

The clay slime generatea in many sand washing operations is usually very difficult to de-water. Treatment of these slimes is often limited by economic considerations and the properties of the solids to a gravity-driven process. The moisture characteristics of kaolinitic slimes from two different sand washing operations were measured.From these curves, equilibrium moisture contents for sedimentation and for drainage were calculated using the methods of soil physics. The validity of these calculations were confirmed by column experiments.The results show that the increased de-watering to be gained by drainage, as compared with sedimentation, is significant. Furthermore, observed rates of outflow indicate that water can be removed considerably morerapidly when drainage is possible.The practical application of these results to the dewatering of clay slimes is discussed.

Jan 1, 1978

By P M. Outhwaite

Everyone present today is especially aware of the need for minerals in this society of ours. The words 'especially aware' were deliberately chosen because this is a meeting of the NZ Branch of The Australasian Institute of Mining and Metallurgy not a dilettante group such as some of our critics. Members of the Australasian Institute of Mining and Metallurgy knew that our great farming industry, our shelter, our transport and our energy supply, are largely dependent on a flow of minerals into this country despite the presence of large coal and natural gas reserves. Flow in was said because New Zealand imports most of its mineral requirements with all the consequential strategic and economic disadvantages. If the above statements are accepted by this gathering it would be a premise fairly stated that New Zealand has a great need to discover and develop minerals.

Jan 1, 1976

By Ghosh I, Vanangamudi M

Experiments have been made in a laboratory heavy media separator at various specific gravities of separation using zinc chloride solution and magnetite suspension as media for different types of coals. The results indicate that the magnetite bath gives at better separation than zinc chloride solution. Even though the probable error remains the same for most conditions of operation, the error area is found to have a wide variation which emphasises the importance of the error area over probable error in evaluating the performance of a cleaning unit.

Jan 1, 1981

By Morgan W. M

It is not the primary object of this paper to treat with the scheme of prospecting in detail, but it is considered that a brief description of the broad lines is necessary so that the significance of the points to be discussed later may be appreciated.The finding of payable gold reefs on the Bendigo field resolves itself into a two-fold problem, firstly the location of quartz bodies, and secondly the location of gold shoots in such bodies. The country rock of the field has been folded and faulted, and the occurrence of known reefs is associated with the fold axes and the faulting. The "lines" of the field are the anticlinal axes, and practically all known reefs are at or near centre country. Very little work has been done on the synclines, which may have some potential value.Quartz has been introduced along the fracture systems, and gives rise to the three main types of reef met with on the field, namely, the "back," which is similar to a bedded quartz reef and is formed along a bedding plane fault; the "saddle," which forms at the crest of the anticline and has the typical shape from which it takes its name; and "spurs," which are irregular masses of quartz, making off reefs of the first two types.As the fracturing throughout the field is widespread and fairly intense, the first problem, that of finqing quartz, is comparatively simple, and any regular system of blocking out the ground will be productive of quartz bodies.*Field Superintendent, Bendigo Mines Ltd. Assistant Field Superintendent, Bendigo Mines Ltd.

Jan 1, 1936