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Environmental management of minesites in general, and management of water discharges in particular, is receiving ever-increasing attention. One key component in the successful design and operation of water management systems is to address the presence of sediment in the water being conveyed. Sediment erosion in the mining environment is often greatly exacerbated by disturbing the ground surface of vast areas of catchment. If sediment avoidance, transport, deposition or release are not adequately addressed, the impact on water management facilities can include loss of storage and hydraulic capacity, more frequent equipment replacement, increased operational costs and potentially environmentally unacceptable sediment discharges to receiving waters. An overview of sediment management within water facilities is presented here, and design of one particular approach, the use of settling basins for sediment removal, is discussed in detail. Examples are used to illustrate lessons learnt where particular approaches to sediment management have been found to be lacking. The common themes in the lessons learnt include the need to characterise hydrodynamic conditions and sediment properties in the water source, to set performance targets for sediment management, and to develop operating procedures to meet these targets under a realistic range of scenarios. The examples show how analysis of expected performance of sediment management can help with planning of operation and maintenance strategies. For settling basins, use of a simulation model that includes the effects of turbulence on settling can provide considerable benefits in optimising basin design and evaluating performance. Even in the most basic approach to sediment settling, establishing performance targets based on design flow and sediment characteristics is critical.

Jan 1, 2003

Consideration was given to the.applicab on of a solvent extraction circuit to be'included in the process'for the-recovery of a high grade product from.:-the Rum Jungle Creek.South uranium ore body.The economics of two alternative processes, firstly the Eluex process which uses an ion exchange process followed by solvent extraction.-of a.high grade sulphuric acid eluate, and secondly a process using direct solvent' extractioh of pregnant leach liquor, were studied. There was a small cost advantage favouring the Eluex process but when other factors were considered, the installation of a direct solvent extraction process appeared the better long term investment. A solvent extraction plant was installed at Rum Jungle in 1962.

Jan 1, 1963

By R Willis, D Cooke, G J. Davidson

Mine-groundwater interaction at the Pasminco Rosebery Mine (PRM), western Tasmania, deserves special attention due to the unique climate and mining environment present. High rainfall and low evapotranspiration result in an excess of water, an uncommon problem at Australian sulfide bearing mines. Research is being undertaken to delineate current subsurface fluid flows and predict future fluid flows in order to improve management after mine closure. Acid mine drainage generation is well developed in abandoned mines throughout the area. If acid mine drainage is not controlled after mine closure, significant environmental degradation could occur in the receiving waters of the Pieman River system. The study area encompasses the heavily forested Mount Black, and underlying PRM workings. Groundwater flows beneath Mount Black through a crystalline fractured rock aquifer with faults and underground mine workings observed to act as the major hydraulic conduits. Recharge is controlled by local precipitation, and the ultimate discharge is thought to be the Pieman River system, which forms the topographic low in the area. Slug tests have been used in conjunction with the mineÆs extensive geotechnical database to spatially evaluate variation in hydraulic conductivity. In fractured rock terrain associated with mining, rock quality designation data can be a useful tool in delineating areas of similar hydraulic conductivity when combined with conventional hydrogeological methods. A GIS, mine planning software, an environmental and a geological database are linked to form the input for groundwater modelling.

Jan 1, 2003

By Royston D

Victoria has an extensive brown coal resource, 202,000 Mt, of which 43,300 Mt is regarded as readily recoverable. This brown coal is located principally in the Latrobe Valley as thick seams and is being extracted at low cost primarily to support base-load electrical power generation. The high moisture content of the coal is partially off-set in many applications by the high reactivity of the coal and the generally low levels of potential pollutants such as ash, sulphur and nitrogen in the coal. Large scale development of this brown coal resource began in the 1920's. In addition to electricity generation, it is used for briquette production, carbonisation of briquettes to char and was gasified for town gas supply to Melbourne (1956 - 1969). The BCLV coal to oil pilot plant at Morwell is a major new initiative in the use of Victorian brown coal. Many other new developments are in place and emerging in the utilization of low rank coals. Examples of these developments are, the large-scale gasification of lignites in the USA, and value-added products such as bulk chars, solid fuels, activated carbons and coal-water mixtures. The Government of Victoria has created the Coal Corporation of Victoria to promote current sales of briquettes and to encourage further new industrial developments based on the State's brown coal resources, in particular the Loy Yang coalfield. The Coal Corporation also has a vigorous product and process oriented research and development Programme.

Jan 1, 1987

Most of the copper deposits in the Lachlan Geosyncline fall within areas having either a common host rock, mineral assemblage, form of ore body or time and method of emplace- ment. On this basis a Cobar-type ore has been recognised in the deposits of the Cobar -- Mt. Hope - Melrose region. The copper ores in the Tottenham-Girilambone area to the east have a different mineral assemblage. In the more rugged Central Highlands nearer the coast copper deposits are generally concentrated either in one of several Ordovician andesite belts, particularly between Wellington and Woodstock, or within Silurian acid volcanics developed in irregular fashion over a considerable portion of this region. In only a few instances is copper known in the granite batholiths which adjoin these volcanic belts. Native copper and magnetite are characteristic of the deposits of the andesite province and it is possible that future mineragraphic studies will indicate significant differences in the base metal sulphides of both the andesitic and the more acid volcanic belts. Ores having similar mineralogy and form to the Captain's Flat deposit are known at various localities in the eastern segment of the latter belt. In the Gundagai area several small copper deposits with associated nickel minerals have been developed in the Coolac Serpentinite belt.

Jan 1, 1969

Geologists often classify ore textures on the basis of the origin of the rock in which they form and the grade of one or more minerals within the ore (Sinclair and Blackwell, 2002, pp 32-36).  Metallurgists, on the other hand, need to know how best to process the ore in order to extract the valuable minerals from it (Petruk, 2000). Geological classification has the following disadvantages:it requires the services of skilled economic geologists, of whom the supply has been dwindling for many years;it is subjective, depending on the perceptions of the individual geologists who make the classification; andit may relate only weakly to processing requirements of the ore. We describe methodology for automatic classification of ore textures from images of drill core. The images analysed are æclassifiedÆ images, in which a particular mineral (or mineral group) is assigned to each pixel. The new methodology is intended to:provide a quantitative and reproducible alternative to traditional geological texture classification,relate to process mineralogy of the ore, andimprove the ore-texture-related input to orebody domaining and geostatistical block models.

Jan 1, 2008

By Kim M

Mukuk gold mine in South Korea produces a pyrite concentrate containing gold associated with arsenopyrite as a gangue mineral. The effects of Portland cement as a depressant on the flotability of arsenopyrite were studied to improve the separation of arsenopyrite from pyrite concentrate containing gold. A series of the fundamental flotation tests were performed using Portland cement as a function of pH and concentration of the collector. Flotation recovery of pyrite and arsenopyrite in the fundamental tests with amyl xanthate showed that arsenopyrite was depressed by the addition of a moderate amount of Portland cement, but pyrite was not depressed by it. In the flotation tests of the artificial mixture samples with arsenopyrite and pyrite, following pH were adjusted to be 10.5 by Portland cement, different amount of amyl xanthate was added. The results from these studies showed that flotation recovery of pyrite was 100 per cent under the condition of some addition of amyl xanthate, but arsenopyrite was not floating at all. Portland cement shows remarkable depression of galena, but its effect on the flotability of chalcopyrite is not as clear. In the pulp under Portland cement addition, chalcopyrite can be easily activated by the addition of sodium bisulphite, whereas galena is depressed more effectively. From the batch flotation tests with the pyrite concentrate, the galena concentrate and the Cu-Pb bulk concentrate from the mines, it was confirmed that the results of the batch flotation tests agree with the results of the fundamental flotation tests. The effects of depression by Portland cement on pyrrhotite, marmatite and stibnite are also discussed briefly.

Jan 1, 1993

By P Walton, L W. Armstrong, D P. Blair

Sydney is the capital city of NSW and has a population of approximately four million people. Eighty per cent of the cityÆs water is supplied by Warragamba Dam, which is situated some 75 kilometres south west of the city centre. A risk assessment was carried out on the dam and future predictions of water flows into the catchment area showed that there was a risk of a one in 700-year flood not being contained by the dam. The predicted loss of life and property damage warranted the construction of an auxiliary spillway on the eastern side of the existing dam to cater for any uncontrollable influx of water. A test blasting program was instigated and the blasting parameters were established that would lead to routine production blasting of the sandstone rock making it more cost effective to excavate. Blast induced vibrations were a concern to the owners and the dam wall and ancillary infrastructure was instrumented with sensitive vibration monitoring equipment during the test blasting phase of the operation. Once the blasting parameters were established from the testing program production blasting was carried out on a daily basis to maintain æstockpileÆ of fragmented ground for the excavation equipment. Blast vibration models were developed to predict vibration levels for more sensitive areas of the dam to give the operators more confidence in their operations. The blast induced vibration levels recorded did not cause any structural damage to the dam wall and the waveform frequencies of the blasting operation were much higher than that experienced during a recent earthquake. The integrity of the SCAÆs assets were at no time jeopardised.

Jan 1, 2001

Titanium dioxide (TiG ) is produced 2 commercially by two methods generally referred to as the "sulfate" route and the "chloride" route. The SCM Corporation, in supplying 15% of the world's demand for TiO 2, uses both of these processes. Of the two processes the sulfate route is generally regarded as the older and more established technology. Worldwide the sulfate route accounts for some 70% of total Ti02 production. However, in the U.S.A. the chloride process accounts for 80% of production. The processes vary in chemistry and raw material requirements. In the "sulfate" process finely ground ilmenite or titanium slag is digested with sulfuric acid to produce a porous "cake" vrnich is extracted with water and recovered liquor. The solution is treated with scrap iron to reduce any ferric ions to the ferrous state which is then crystallised and removed as ferrous sulfate heptahydrate. The liquor is concentrated by evaporation and hydrolysed to form the insoluble hydroxide which is filtered and washed free of impurities. This is converted to the dioxide by calcination at 800 - 1000¦C and milled to break up any aggregates. The "chloride" process uses a higher quality feedstock of natural or synthetic rutile and/or high grade titania slag. The feedstock is mixed with ground high-purity coke and chlorinated at 950¦C in a fluidised bed. The resulting crude titanium tetrachloride is purified by distillation and chemical treatment. The purified titanium tetrachloride is burned with oxygen or oxygen enriched air to give titanium dioxide and chlorine, which is recovered and recycled to chlorination. Titanium dioxide pigment from both processing routes undergoes similar finishing techniques. It is subjected to further stages of wet and dry milling, then coated with layers of inorganic oxides in order to enhance its properties for specialist applications.

Jan 1, 1986

The Ausmelt Catalytic Waste Converter (CWC) has been developed for use in the treatment of industrial wastes and for the recycling of secondary materials. Ausmelt Technology uses a top submerged lance system within a versatile and efficient slag bath reactor. High temperature pyrometallurgical reactions are carefully controlled within an oxidised molten siliceous slag such that metals can be extracted from waste feedstock for recycling, with non-volatile elements reporting to the slag, usually as oxides. Modification of the slag chemistry results in a final slag product that is stable, vitrified and is able to pass standard leach tests such that it is safe to discard or be used in civil engineering applications. Toxic components in the wastes such as organohalides can be completely destroyed and are prevented from reforming. Waste to energy conversion is practiced by the addition of a heat exchanger/steam generator in the converter offgas system. The Ausmelt CWC has been used for recovering zinc from residues and slags, treating spent potliner (SPL) from the aluminium industry and a wide range of electronic and other potentially valuable waste materials. Methods of monitoring the exhaust gases at different stages in the CWC gas handling system are discussed. The assay of these gases prior to emission is used to assist in the control of the converter chemistry to ensure the complete oxidative breakdown of the feedstock.

Jan 1, 2002

As an environmental "pollutant", noise is different. For one thing, it is localised (as opposed to transfrontier) and, for another, relatively low levels can trigger very strong human reaction. The reactions, which are annoyance-based, range from mild to violent and do not always correlate well with the levels experienced. This paper draws on technical aspects of noise to consider control and control principles and balances them with the subjective nature of the perceptions and reactions. It is critical to bear in mind that health effects resulting from noise are secondary to the primary human reaction. It is also important to appreciate that annoying noise levels are usually well below those which cause hearing loss. Large mines tend to be remote from cities and towns and the country surrounding such mine sites is often inhospitable. In general, residences near large mines are committed for use by mine personnel and annoyance from mining noise would be rare. Noise problems at long term operations are often a result of secondary activity or land use. As a pioneer mining community develops, secondary and service industries may be established and a township created. With changes in way of life, the perception of problems also changes. Therefore, it is never too early to plan for noise abatement, particularly because noise is only one of a number of environmental and community concerns. Ihny environmental problems are associat- ed with development or expansion of smaller open cut facilities such as hardrock quarries. There is an ever-present need to reduce product cost by mining or quarrying deposits close to the end user and many local authorities have to operate quarries for undertaking their civil engineering responsibilities.

Jan 1, 1987

By Lawson F

Chrome chemicals are commercially produced by the alkali roasting of the chrome-bearing ore chromite with sodium carbonate. In order to ascertain the influence on the extent of reaction of the replacement of Mg(II) for Fe(II) in the chromite spinel structure and the presence of acidic oxides in the gangue material, a series of roasting experiments was conducted using chromite materials from a number of different locations. The roast feeds and products were chemically analysed and the major compounds identified using X-ray diffraction and scanning electron microscope techniques.Mg(II) replacement for Fe(II) in the chromite structure does not appear to restrict the amount of "available" chromium for reaction.Under the test conditions, namely an atmosphere of pure oxygen, finely ground chrome-bearing material, a roast temperature of 950°C and the stoichiometric amount of sodium carbonate to react with the chromite, the yield of water-soluble sodium chromate was able to be expressed as %yield = 104.5 -1.58 × %AI2O3 - 2.23 × %SiO2 for chromite samples containing alumina in the range 7.8 to 27.8 per cent and silica in the range 2.9 to 7.4 per cent.

Jan 1, 1984

By C Hertle, B Goebel, R Fabre

The mining industry maintains a ælove-hateÆ relationship with water. Dewatering, aquifer, water disposal, irrigation, process water, tailings water, run-off water, seepage, leachate and sumps are all terms that are used on a daily basis in the mining industry, highlighting the numerous water usages on site and their associated quality. According to the Australian Bureau of Statistics (2001), each year the mining industry consumes over 530 000 ML of water. The increasing recognition of water as a limited and valuable commodity, and the associated environmental concerns with the management of water disposal to the environment has led the industry into improving on-site water management. Progressively, water balance models and water reuse strategies are being developed, incorporating more sophisticated water treatment processes. By way of example, membrane technologies, once restricted to industries such as the pharmaceutical industry or the drinking water industry, are now entering the mining world with the aim of producing clean water of suitable quality for ore processing or for advanced treatment prior to release to the environment. This paper will provide a review of the threats and opportunities linked to water use and recovery/reuse in the mining industry in Australia. It will open with an overview of current water usage and associated quality for various mineral industries and continue with identifying the threats and limitations associated with the quality of available water. It will then present how newly developed water treatment technologies and assessment tools can be incorporated into the system to enhance the recovery and reuse of water on site, reduce the risks associated with securing long-term water supply and further improve production, environment and safety (health risk control).

Jan 1, 2006

Since the introduction of the Neil George Five Point Safety System, to the underground sections of The Zinc Corporation, Limited and New Broken Hill Consolidated Limited mines in March, 1969, the Disabling Injury Frequency Rate has been halved and shows signs of contin- uing to fall. The total accident frequency rate has also fallen, although the decrease has not been as significant. Before the introduction of the Neil George Safety System, analyses of the direct causes of accidents showed that approx- imately 25 per cent were caused by "unsafe conditions", while 75 per cent were attribu- table to "unsafe acts". Within twelve months of introducing the system, these percentages had significantly changed to 7 per cent unsafe conditions and 93 per cent unsafe acts. Today, the figures are 3 per cent and 97 per cent respectively, and these figures clearly show that the main emphasis in the current programme must be directed towards making the operating men safety conscious. The effort must be focused on changing the minds of men.

Jan 1, 1975

By N Ozawa, R Kaneko, M Arimit

The Mitsubishi Higashitani limestone mine is a ten million tonne per annum operation located near the city of Kitakyushu on JapanÆs western island of Kyushu. Higashitani is one of the largest limestone mines in Japan and accounts for about five per cent of national production. Blasting practices at the Higashitani mine involve the use of bagged ANFO, dynamite primers and non-electric detonators. Regulations in Japan prohibit the use of site mixed bulk explosives. Blast size is usually around 17 000 tonnes with 20 holes in a single row, two or three blasts are fired per day at a powder factor of between 0.25 and 0.32 kg/m3. As part of a program looking at oversize reduction Mitsubishi, Asahi and Orica agreed to conduct a joint project at the Higashitani mine to investigate the relationship between the powder factor and fragmentation. The first stage of the project was to benchmark the current blasting performance. Five blasts were monitored in each of the 210 (hard rock) and 220 (soft rock) areas of the mine. OricaÆs Powersieve« software was used to measure fragmentation and total rock breaker hours were also recorded for each blast. OricaÆs computer blasting simulation model Sabrex« was used to prepare revised blast designs with a higher powder factor and predict their performance. The performance of these blasts was monitored using the same methods.

Jan 1, 2004

By C P. Kramers

The need to provide a sufficient quality and quantity of backfill continues to increase in South Africa, particularly as related to the increasing depth of mining. More and more applications require well designed fill systems either as classified or cemented backfill, and in some applications even tailings/aggregate based backfills. The paper discusses developments in backfill technology in South Africa with special emphasis on reliable system designs and operations, particularly as related to the preparation and hydraulic transportation aspects. Approaches for the alleviation of previous problems associated with premature pipe failures in vertical shaft columns for the distribution of tailings based backfills are discussed. Resulting from CSIRÆs developmental work, reliable full-flow systems, which can operate at low system pressures, have become a common practice, provided that backfill flowrates and internal pipe sizes are well matched. This aspect is reviewed. With regard to the tailings/aggregate based backfills the paper reviews some of the results of comprehensive in situ monitoring and the development of such systems. It is shown that a thorough understanding of the effects of aggregate top size, fines content and slurry relative density is required in order to ensure the restartability of temporarily shut-down pipelines. Some innovative technologies for the comminution of development waste underground to yield aggregate products potentially suitable or hydraulic transportation and backfilling, are briefly discussed.

Jan 1, 1998

Every estimate of ore reserves necessarily contains an assumption in regard to the specific gravity of the ore. This assumed figure may be based on experimental data, on textbook data, or on a reconciliation of past tonnage estimates and production figures. Not infrequently it is simply a guess - shrewd or otherwise.Errors in the density factor are not likely to be serious in gold-quartz mines-or, at least, not so serious as in base metal mines. It is to the closer determination of ore density in the latter that this paper is devoted. Moreover, the remarks apply to ores which show no appreciable pore space.Not many ore bodies are sufficiently homogeneous to allow of a truly representative factor being obtained by the simple testing of a few specimens of ore, or by the weighing, after breaking, of a carefully measured block. The empirical figure derived from a comparison of past ore reserves and actual production can never truly describe conditions other than those now past; no real link with ore as yet unmined is provided. The dilution of heavy ore by waste is not exposed by this method, but is effectively cloaked. Anyerrors in past estimations of ore reserves are transmitted, by way of the density factor, as a source of error in all future estimates.ObjectIons may be raised to the practice of weighing measured blocks of ore in the case of any but a very homogeneous ore body. Even then, the exact composition of the block weighed, and an indication of whether its moisture content is representative of the whole, are difficult to determine.

Jan 1, 1940

By Adams DG

At Cook Colliery a combination of main injection of the face coal, and mining into the floor has proved successful for the recovery of faceline falls.The strategy for preventing falls relies upon a conventional method of longwalling. improved geotechnical predictions, and continuous assessment of strata conditions. Different categories of faceline stability are recognised and an operating procedure has been developed for each category.

Jan 1, 1991

By Willis G. M

Preliminary experiments have shown that, when used in a fusedchloride electrolyte, titanium carbide anodes dissolve yielding lower titanium chlorides which nlay be electrolysed in situ to produce a cathode deposit of pure titanium metal. The anode residues are easily withdrawn from the cell. Further experiments have established the operating conditions for maximum efficiency in the process.The process is essentially two-stage, viz.: (1) titanium carbide production, (2) electrolysis producing metal. Power requirements appear to be moderate and this fact, combine·d with the simplicity of the process make it attractive as a possible method for the production of titanium.INTRODUCTIONDue to the high reactivity of titanium and its, affinity for oxygen and nitrogen, the extraction of this metal generally involves the use of halide. compounds as intermediates. For instance, magnesium reduction of titanium tetrachloride is the basis of the well established Kroll process and electrolysis of the lower chlorides in a molten salt bath has been proposed by Cordner and Worner (1951, p. 358) and others (Brenner and Senderoff, 1952, 223C; The TitaI Company (Inc.), 1952) as means of production of the metal. Thedifficulty of preparation of these compounds prompted a search for an alternative extraction process. The fact that aluminium, an equally reactive metal, has been prepared by electrolysis using aluminium alloy anodes suggested the possibility of a similar process for titanium production.The Titan Company (Inc.) (1952) has patented the use of crude titanium metal anode, but it was thought possible that a metallic compound, such as the carbide, could be used for this purpose. Although Lorenz and Kaufler (1909) suggested the use of carbide anodes for metal production, no...

Jan 1, 1956

By Koeng R, Richardson M, Hoare R

A discrete event computer simulation model was developed for two of the stoping methods currently used at the Z.C. Mines Broken Hill oper- ations. The objective in undertaking this project was to provide an effective tool for mine planning and design to allow comparisons of alternative extraction strategies and attempt to optimise the allocation of capital equipment and human resources. The Slam II simulation program was used in conjunction with ,a com- monly used data editor, text editor and graphics package to allow the simulation to be done on a personal computer with minimum training requirements. The computer hardware used was a portable computer cur- rently available using 80386/20MHz electronics. Specific logic techniques were developed to allow the Slam II language to simulate mining opera- tions because it was originally developed for manufacturing and com- mercial simulations. The design of the model was based on observations and a data collec- tion campaign. The model was designed with flexibility which allows simple editing of the input data which includes: - Insitu volumes - Development statistics -Loadout efficiencies -Loader speeds, availabilities and capacities -Chute numbers, volumes, distances and blockage statistics -Trucking statistics -Work schedules -Utility statistics

Jan 1, 1988