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The carbonatite-hosted apatite deposit at the Cajati open pit mine in the Jacupiranga igneous-carbonatite complex is located in south-eastern Brazil. The major styles of apatite mineralisation include veins or veinlets, small pods or patches, disseminated apatite and locally massive aggregates. The metallurgical concentration of the apatite is accomplished by grinding the carbonatite, removal of magnetite with a magnetic drum, size classification with cyclones and flotation to suppress carbonates and collect apatite. To examine the character of the apatite grains and to apply those observations to apatite beneficiation, specimens of carbonatite were collected from recent exposures in the mine and from selected drill holes. This study utilised a variety of microscopy methods, including transmitted and reflected light, cathodoluminescence (CL) and scanning electron microscopy with wavelength-dispersive spectrometers for mineral compositions. It was found that LREE, Na and Sr are the main elements replacing Ca in the apatite, with relatively low oxide contents (<0.5 per cent, but up to about one per cent for Sr). LREE and Sr contents consistently increase in the latest intrusions (C4, C5 and SP24). Chemical and morphological modifications of apatite were recognised to be related to detrimental effects on flotation recovery. Three examples illustrate this relationship: 1.  Apatite with reddish CL is fractured. Locally that apatite exhibits no CL due to CL quenching caused by iron entering the apatite structure.2.  Apatite from the xenolith-rich area exhibits abundant fine, platy silicates that appear to interfere with flotation and lower apatite recovery.3.  So called æhardÆ apatite, which is more difficult to grind, occurs in an area in the mine that was affected by hydrothermal activity. That activity is evidenced by the development of a bright, white CL rim in the apatite, and by the presence of late veins of carbonates and sulfides that fill fractures and appear to contribute to higher cohesiveness of those apatite grains.

Jan 1, 2008

The occurence of high silver values in the oxidised zone of the main lode at Broken Hill is well known as a large factor in achieving the early fame of Broken Hill, and the minerals of this zone form a long list, which has been tabulated by G Smith*, and includes...

Jan 1, 1926

By S Das

Deposit-10/11A is situated in the iron rich Bailadila region of India comprising haematite ore of average grade 65 per cent Fe. The deposit production line was commissioned in the year 2002 having a capacity of 5 Mt/a. The plant has the state of the art mineral processing equipments.The ore is transported from mines to crushing plant by means of dumpers. The ore is comminuted in two stages to get 150 mm top size product and this product is transported through conveyor system and is stored in silos as feed stock for beneficiation plant. In the beneficiation plant this crushed product is wet screened in two stages to produce a product of lump (-150 + 10 mm) and fines (-10 + 3.15 mm). The product of -3.15 mm top size is fed to primary classifier for a size separation at 150 µm. The resultant product (-3.15 mm + 150 µm) is dewatered and transported to fi ne ore product stock yard through conveyor system. The minus 150 µm material from classifier overflow is fed to cyclones (508 mm cyclone battery with an apex of 65 mm) for desliming at 45 µm and to recover ultrafi nes (-150 + 45 µm). The cyclone overfl ow slimes (-45 µm) along with water is treated in lamella thickeners to recover process water. The thickener underflow material is transported to tailing pond (discharge rate is 300 m3/h at a specific gravity of 1.4) by pumping through HDPE (high density poly ethylene) pipeline and the over flow water is being recirculated. The water requirement for beneficiation is approx 1.5 m3 per ton of ore.This paper aims at identifying and quantifying the factors that affect the overall plant performance (grade and recovery) during the different seasonal variations especially in the rainy season (mid-June to end October). The effect of seasonal variations on unit operations such as milling, classification, thickening and filtration are discussed. Specific cases are presented as examples and recommendations are formulated.

Jul 11, 2011

By Eupene GS, Cheong GE

Operations at the Mount Bonnie gold/silver project are described. The project is based on the gossan of a stratiform and stratabound polymetallic sulphide deposit. The gossan contains approx- imately 100 000 tonne of ore grading 8g/tonne Au and 230g/tonne Ag. This is mined in an open cut, and transported to a stockpile area lkm away, from which it is fed to the treat- ment plant. The ore is crushed through two stages and fed to a fine ore storage shed, from which it is reclaimed, milled and cyanide leached in draft tube agitators. The pulp is filtered using a horizontal belt filter to recover a pregnant solution. Silver sulphide is precipitated using sodium sulphide solution, and collected as a mixed sulphide/precoat concentrate on a drum filter. The solution is then passed through carbon columns where the gold is adsorbed and is subsequently recovered by methanol desorption using a process developed by Micron Research, and electrowinning. Modifications to the treatment plant circuit based on operational experience are Described.

Jan 1, 1984

The original design of the Bougainville Copper Limited (BCL) concentrator took cognisance of the constraints imposed by the topography, the need to minimise capital cost, and the need to allow for plant expansion which, it was known, would be necessary to maintain copper and gold production as head grades declined.At the same time as spare slots have been taken up with additional equipment, technological innovations have been embraced whenever there appeared to be a chance of improving the productivity ofexisting equipment, or replacing it with a more efficient alternative.There are many examples of this in the BCL concentrator in the areas of process control, process design, instrumentation, materials handling, equipment design and wear part technology.Current process developments also pursue the latest technology. The development of the Omnicone crusher, flotation control, tailings water reclamation, and the variable speed gearless drive on the No. 13 mill are prime examples.

Jan 1, 1986

By Mimura K

The carbon reduction of tantalum pentoxide was investigated in a plasma-arc furnace. The sample was a mixture of tantalum pentoxide and graphite, vacuum pressed into a briquette and was reduced at about 3100¦C. Argon was used as the are gas. The optimum mixing ratio of carbon and tantalum pentoxide, C/Ta205 is 5.10--5.15. The sample, weighing 7 g is fused within 60^ 70 seconds by plasma-arc heating and the reduction of molten tantalum oxide with solid carbon pro- ceeds rapidly to approximately 99.5 % Ta during this period. The reduction that follows in the molten state is slow. Within about 10 minutes, the maximum tantalum content of the massive metal product reaches 99.9 % and the oxygen and carbon remaining in the product are 50 ppm and 400. 500 ppm respectively.

Jan 1, 1980

Proposals for engineering works in the River Dement in recent years have been made in the context of very little geological informat- ion. Breakage of the Tasman Bridge, forced a complete re-appraisal and collection of inform- ation in order to select a new site and predict problems. Seismic, magnetic and gravity methods foll- owed by drilling have allowed an assessment of the nature, thickness and distribution of mater- ials underlying the river bed. Key discoveries included recognition of low seismic velocity silts (1100 m/s) and a separate channel for the river since the Late Tertiary.

Jan 1, 1977

By McDougall I, Claoue-Long J

A combination of high precision 40Ar/39Ar and U-Pb dating has been used to determine the age of hydrothermal minerals and host rocks in a number of Lachlan Fold Belt (LFB) gold deposits in New South Wales, Au4 ralii In particular, this investigation demonstrates that the UAr/ Ar technique of K-Ar dating can be used to determine the timing of mineralization in Palaeozoic systems.A close temporal link between mineralization and Late Ordovician to Early Silurian magmatism is indicated by the dating work. Hydrothermal sericite from the Goonumbla p8rph gy Cu deposit and Glendale Au prospect yieldsAt/ Ar step heating ages between 437.9 ¦ 1.1 and 441.2 ¦ 1.1 Ma (16), and4 minjrnum age of about 425 Ma has been obtained by Ar/ Ar dating of hydrothermal amphibole from the Browns Creek Au-Cu skarn deposit. Hydrothermal aluniI8 frog the Gidginbung epithermal Au deposit yields reset 44 Ar/ Ar ages of 401.0 ¦ 1.3 to 417.3 ¦ 1.3 Ma (16). U-Pb dating by ion microprobe on magmatic zircons from the vicinity of the Goonumbla and Gidginbung deposits gives ages of 438 ¦ 3.5 Ma (2 6), and 435 ¦ 2.5 Ma (2 (7) respectimly, W a minimum age of 435 Ma has been obtained by Ar/ Ar dating of magmatic phases from volcanic rocks adjacent to the Browns Creek skarn deposit. Magmatic episodes near the Sheahan-Grants gold skarnpost give ages of 479.2 ¦ 1.1 and 467.9 ¦ 4o1 by 'Ar/ 9Ar dating of magmatic amphibole. Most Ar/3yAr age spectra show the effects of partial Ar loss at between 360-420 Ma, probably due to heating caused by granitoid emplacement.The radiometric dating work in this paper suggests a restricted metallogenic epoch in the Late Ordovician-Early Silurian LFB, NSW, of similar duration to that found in the Andean margin and the western Pacific island arcs around the Pacific Rini.

Jan 1, 1990

By A Parbhakar-Fox, B G. Lottermoser, N Fox

"Determining the deportment of economic and environmentally significant elements in sulfidic mine materials (eg ore, gangue and waste) requires the use of advanced microanalytical techniques, including electron microprobe analysis (EMPA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Sulfidic boulders were sampled from an acid rock drainage impacted ephemeral stream adjacent to historical copper-silver workings at Baal Gammon, northern Queensland. The abundance and deportment of a range of trace elements and precious metals were analysed in these samples. Whilst many of these elements represent a potential environmental risk if leached from sulfidic rocks into streams in the surficial environment, significantly some of these elements (eg In, Sb and Co) represent specialised metals that are currently considered to be in critical supply.Sulfidic waste rock material at Baal Gammon is dominated by chalcopyrite, arsenopyrite, pyrrhotite and pyrite. Microanalytical investigations revealed that chalcopyrite contains significant quantities of In, Sn, Ag and Zn either substituted directly into the crystal lattice or occurring as discrete sphalerite and stannite inclusions. Arsenopyrite, which may comprise more than 50 per cent of some boulders, is notably enriched in Sb, Co and Ni but also contains inclusions of sphalerite, chalcopyrite and stannite. In contrast, pyrrhotite contains no trace elements of economic significance, but instead represents a likely contributor to acid generation during oxidation in the surficial environment. Trace metals (eg In, Sb, Co, Ni, Zn) are liberated during sulfide oxidation of these boulders in the surficial environment, generating a metal-rich, low-pH leachate.Fe-oxides precipitated as rinds on the surface of these boulders under low pH conditions also contain abundant As, Bi, Sn, Cu and Zn. Abandoned or historical mines represent potential sources of metalliferous drainage that poses potential environmental risks to water and habitats. However, sulfide-rich historical waste rock, stockpiles and processed waste (eg tailings) at abandoned mines may also represent significant sources of critical (eg indium) or other significant metals (eg Sn) that if liberated economically could improve environmental conditions in and around abandoned and historical mines.CITATION:Fox, N, Parbhakar-Fox, A and Lottermoser, B G, 2016. Critical and Deleterious Metal Deportment in Sulfidic Waste Rocks, Baal Gammon, North Queensland, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 173–182 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By Hayes P. C

The reduction of small, dense zinc oxide (ZnO) samples in CO/CO2, and CO/N2 gas mixtures has been investigated at temperatures between 900 and 1100¦C. The microstructural characterisation of the reacted and partially reduced samples was complemented with measurements of the rates of the reactions. The mechanisms and kinetics of reduction of zinc oxide were found to be dependent upon the CO partial pressure, the oxygen potential of the gas mixtures, temperature and degree of reduction.

Jan 1, 1991

By M D. Goodz, Wright R. F

This paper highlights the importance of accurate observational technical reports compiled by Mining Geologists and Engineers. Before uncovering the original reports in July 1992, all previous investigations discounted returning to old mining areas on the belief that all operations were suspended because they were 'unpayable'. However, the detail of the original reports removed any doubt of the economic value of retrieving remnant ore.The important feature was that the description of 'unpayable' by GMA could be equated to 11.6 - 35 g/t over the history of the mine. On the basis of these reports the Morning Star mine has been re-opened.

Jan 1, 1993

By Reeves T. J, Hansen J. Y

Dense medium cyclone theory, supported by extensive experimental and plant-scale evidence, demonstrates that medium rheology (stability and viscosity) substantially affects cyclone performance in mineral applications.Two instruments have therefore been developed to allow medium stability and viscosity to be-monitored in the plant environment. The instruments are described, and examples are given of their application in full-scale plants.

Jan 1, 1989

By Garg R. K

Himalayan ranges on the northern border of India are source of many perennial rivers and suitable sites for large dams have been located therein. However, Himalayas are young mountains and comprise of comparatively weaker rocks having adverse geological features like shear seams, thrust zones, minor and major faults and intense jointing. Tehri dam project under construction, is located in lower Himalayas. It envisages construction of a 260.5 m high earth and rock fill dam and an underground power station of 2000 MW (Eight machines of 250 MW each, four of which will be reversible) installed capacity. This dam will be the highest and the underground complex will be the largest to be constructed in India in the Himalayas. The under- ground complex comprises of 25 km of tunnels varying in diameter from 6 m to 11 m and seven large cavities of various sizes, the biggest being 22 m in width, 194 m in length and 65 m in height. Rock formation in the power house complex belong to phyllites having various joint sets spaced from 0.5 m to 3 m. Due to the poor geological conditions and closely spaced net work of large cavities, the planning, analysis and design of the cavities is a challenging job. Many aspects have to be considered in determining the sizes, locations and orientations of the various cavities taking into account the properties and jointing pattern of rock mass, functional requirements and economics. Correct evaluation of loads and forces is necessary for economical design of supporting system for the various cavities. Rock loads on the roof of cavities and their supporting system will be assessed with the help of the latest methods. The stability of the rock mass around the cavity will be evaluated by elasto- plastic method using finite or boundary element techniques. A scheme of field investigations, laboratory tests and instrumentation for deter- mining rock properties in preconstruction stage and for monitoring behaviour of the underground cavities during and after construction is envisaged.

Jan 1, 1987

Programmes of environmental investigations to identify and minimise impacts and satisfy government and community requirements have become an integral and rate determining component in the planning and development of new mines in Australia. This paper reviews the essential features of the environmental project management Function.

Jan 1, 1983

The key to the successful debt funding of a new mining project, whether in economically established or developing nations, is the submission of a comprehensive feasibility study. The feasibility study forms the basis from which the resource banker can construct financial models which govern the amount of available funds, the conditions which control the supply of such funds and the time period over which the loan may be repaid. The bank will wish to ensure that the feasibility study is the best representation and confirmation of reality possible because this model is the basis of the loan security package. Thus the study will be vigorously interrogated by independent experts in all its elements including the ore reserve, mineability, metallurgy, operating and capital cost profile, environmental factors and management.

Jan 1, 1995

By J Visser

Dust mitigation has long been seen as nothing more than managing a nuisance issue, but the reality is that poor dust management can lead to one or more of the following negative consequences: an increased risk of safety incidents, lost revenue, reduced and possibly even lost licence to operate, regulatory intervention, high staff turnover and/or absenteeism and occupational health and safety (OH&S) issues. Dust mitigation and management is not a black art; rather it is a scientifically driven process that can provide an opportunity to increase profits, increase the companyÆs status as an excellent corporate citizen, enhance staff retention and reduce the safety risk profile of the operation.The way to achieve success in dust mitigation and control is to apply the scientific method to each problem that can arise and plague any operation by using current industry best practice. This method of dust problem-solving can be applied to dust issues arising from specific dust sources and locations. The dust sources can include wind impacting on stockpiles, open areas, tailings storage facilities, moving train and truck loads, vehicular traffic on roads, the operation of shovels, front end loaders, draglines and other equipment, as well as ore movement on conveyors.The solutions will come from a combination of deployment of dust collection equipment, dust and moisture monitoring equipment, the appropriate application of water and chemicals, the introduction and maintenance of appropriate barriers and the use of predictive data from local and public weather stations. The paradigm shift required is to view dust mitigation as one aspect of normal operational practice, not a ænice to haveÆ or æunnecessary expenseÆ as most operators currently view it. This attitude is becoming more important as more and more local communities oppose the development of mines. One of the reasons for this local opposition is the inevitable dusty environment that is usually associated with mining.Dust mitigation is not a significant expense if correctly designed and included into the system, either as part of the original design of the operation or as a brownfield installation after the fact. Indeed, there is always a loss of revenue associated with dustiness resulting from ore movement and avoiding this goes a long way to paying for any associated dust mitigating costs.CITATION:Visser, J, 2013. Dust mitigation - changing the paradigm, in Proceedings Iron Ore 2013 , pp 27-38 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By K Dudley, D Readett

The design of entrainment control processes in copper SX plants has been studied by use of models based on achievable plant performance. A number of alternatives have been assessed for their suitability in minimising the transfer of deleterious species from PLS into the electrolyte. The position of the wash (scrub) stage in the circuit, either before or after the loaded organic tank, has been the subject of considerable debate. The modelling shows that at ænormalÆ entrainment levels, the performance of the circuits are very similar. However at high entrainment levels the selection of the wash after the loaded organic storage has significantly lower transfer of contaminants. When considering the inclusion of a loaded organic coalescer the results of the modelling again show that the best circuit has the loaded organic storage/coalescer before the wash stage. The overall control of EW contaminants includes both a wash stage and an EW bleed flow. The total water use for these two flows is shown to go through an absolute minimum. The minimum flow rate is not greatly dependant on the total entrainment from the SX settlers. This can be a useful operating strategy if the quantity of high quality water for make up is limited by the capacity of the water treatment plant (eg RO). However the minimum cost option is to maximise the flow of water to the wash stage and minimise the EW bleed stream. The main driver for this is the cost of the cobalt sulphate contained in the electrolyte. Some results from the latest circuit modifications at the Nifty and Girilambone Copper Projects are presented to confirm the benefits of using both coalescing systems and a wash stage. The EW bleed has been reduced to a level that is less than the loss internally in the SX stage to stage entrainment. There has been an occasional need to add chloride to the EW to maintain sufficient concentration to act as a growth modifier.

Jan 1, 2002

By Sakai S, Suga S, Bisque RE

Soil gases were collected on activated charcoal, analyzed by computerized mass spectrometry and treated with multivariate statistical pattern recognition to determine the diagnostic geochemical signature associated with the Okuaizu Geothermal Field in Japan. From this a geothermal model was developed and compare to 175 "unknown" samples in a 250 m spaced grid over 30 1Qn2 mapping the areas with a matching geochemical character. Faults and fractures were generally located by the presence of high molecular weight components. Following the initial survey, the faults in two specific areas were precisely located by a second survey with samples at 10-30m spacing. Where earlier geochemical surveys had placed anomalies 1-2 Km northeast of the geothermal center, the fingerprint survey accurately mapped the system and detected several faulted zones. It was not misled by hot springs located away from the geothermal System.

Jan 1, 1987

The B.R.G.M., through international experience gained over many years, has become very skilled in alluvial prospection, particularly for diamonds. The research laboratories within the B.R.G.M. have also been active in creating new mineral processing equipment,. some of which is directly applicable to such prospection. One such development, the mobile prospection unit, is described and -its application in mineral exploration is demonstrated by a consider- ation of the diamond search in Australia and the general exploration of the Massif Armoricain (France). Because this latter study was fundamental in the development of the concept of "mineral-geochemistry", and its application in mineral exploration, it is also briefly described.

Jan 1, 1980

By G Swayn, J Harpley

Spent Pot Lining (SPL) is an unavoidable waste product of the electrolytic process in the smelting of aluminium. SPL is considered to be a hazardous waste in various countries because it contains significant quantities of absorbed fluoride along with traces of cyanide. The disposal of SPL has been primarily in landfill because of difficulties in the development of a successful techno-economic SPL treatment process. Increasing concern about SPL landfilling practices is resulting in regulations in some countries to ban this form of disposal. As a consequence stock piling of SPL is occurring in an increasing number of countries pending the development of a successful treatment process. In 1992 Portland Aluminium investigated a SPL treatment process based on pyrometallurgical technology and approached a company called Ausmelt in Dandenong, Victoria, Australia, to ascertain if their submerged lance technology furnace process would be suitable to treat SPL. This approach resulted in Portland Aluminium, Alcoa and Ausmelt personnel working together on trials during 1992 - 1994 in Ausmelt's demonstration furnace to produce a slag and off gases containing hydrogen and sodium fluoride. The trials also evaluated the effect of oxygen enrichment to increase the concentration of hydrogen fluoride and the ability to recycle sodium fluoride particulate produced as the furnace off gases cooled. Other separate developmental work by Portland Aluminium, using CSIRO, resulted in the production of aluminium fluoride from the offgases from the pyrometallurgical process. The results of these projects influenced Portland Aluminium and Alcoa to authorise up to $A26 400 000 in December 1995 to construct a Research and Development processing facility to treat SPL at Portland. The Portland Aluminium unique gas treatment process converts hydrogen fluoride in the furnace offgases to aluminium fluoride in a multistage fluidised bed reactor, designed by Portland Aluminium. The aluminium fluoride produced in the reactor has been trialed successfully in Alcoa's aluminium smelting process as a replacement for imported aluminium fluoride. The installation in mid-2001 of a slag granulation system has enabled the production of a granulated vitreous slag having leachability qualities that conform to Victorian EPA criteria for the unrestricted use of the granulated vitreous slag from 'The Alcoa Portland SPL Process'. The unrestricted use of the granulated slag successfully completes 'The Alcoa Portland SPL Process' which treats the hazardous waste material SPL and converts it into non hazardous useful products.

Jan 1, 2002