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By L Smith, R Beckie

Controls on environmental loading from acid rock drainage (ARD) are not well understood in waste rock material. In particular, relationships between subsurface flow and the timing, duration, and intensity of leaching of metals and acidity from waste rock dumps remain ill defined. This study investigates field-scale relationships between subsurface flow processes and geochemical processes in unsaturated waste rock. A 12-metre tall, unsaturated waste rock pile, constructed in 1994, was deconstructed and sampled at Key Lake, Saskatchewan, Canada, during the summer of 2000. A detailed sampling methodology was developed to characterise physical and chemical properties of waste rock material within the waste rock pile. Physical properties were characterised by measuring soil-water suction, volumetric water content, and grain-size distribution at 60 random locations within the pile and grain-size distribution at 20 grid locations within the pile. Attempts to develop a field-based soil water characteristic curve from physical field-data failed due to spatial variability and hysteresis of waste rock properties. As a result, grain-size distribution was used as a relative measure of subsurface flow. Paste pH, pore-water geochemistry, mineralogy, and water-soluble extraction results were used to characterise geochemical processes and sulfide oxidation at each of the 20 grid locations. Geochemical characterisation results demonstrated the preferential weathering of marcasite relative to pyrite and chalcopyrite. Dolomite was the main buffering carbonate mineral. Gyspum, jarosite and iron oxyhydroxides were the main secondary minerals. Pore-waters contained up to 800, 11.7, and 6 mMolar (78 000, 690, 1400 mg/L, respectively) of sulfate, nickel, and uranium, respectively, suggesting significant weathering has occurred. Measures of weathering indicators show no discernable correlation with grain-size distribution nor do they show any spatial relationship within the sampled grid. Reasons for this may include limited duration of waste rock exposure to weathering and development of fluid flow-paths, and limitations of characterisation methods used. Indeed, six years may not be long enough for weathering patterns to develop due to fluid flow-paths in this unsaturated waste rock pile.

Jan 1, 2003

By Scott IR

In stratigraphic orebodies, estimation of footwall and hangingwall location is often of more importance than grade estimation. Contoured grade estimates often produce smeared boundaries and the use of accumulations and thicknesses as variables re-introduces the original problem: location of the point at which the estimate is to be made. The paper introduces statistical and geostatistical techniques for the solution of the problem and illustrates the techniques with a case study from Mount Isa, one of the world's largest producing silver-lead-zinc deposits. Solutions for calculating variograms in orebodies of variable dip, strike and plunge are presented together with relative variograms for individual metals, metal accumulation and orebody thickness. Optimal methods for hangingwall and footwall location are introduced and illustrated with an example. Orebody boundaries are then kriged after which individual metal grades are kriged within the estimated boundaries. The boundary estimates are compared with manually interpreted boundaries and known boundaries in mined-out areas. Grade and tonnage estimates are compared in mined-out areas.

Jan 1, 1986

Western Australian tin deposits are similar to those of other Precam- brian terrains in that they are mainly associated with rare-metal pegmatites, in which cassiterite is found with minerals containing any or all of the elements Ta, Nb, Be, Li, Cs, Rb and the rare earths.. They differ from Phanerozoic deposits where cassiterite occurs in quartz veins, greisens, dis- seminations in granite or sulphide lodes, and is associated with minerals containing W, Mo, Bi, Sb, As, Ag, or Cu. The main tin production in Western Australia has come from the Pilbara Block where the more important tin- bearing pegmatites are related to a younger granite phase, and from Green- bushes where large albite pegmatites intrude ?Proterozoic metamorphic rocks. The more important tin deposits in the Pilbara Block, and those in the Halls Creek and Murchison Provinces, are related to granites which are richer in Si and K and poorer in Ca, Mg, Fe and Ti than 'average granite'. The tin granites tend to have higher than average contents of Sn, Rb and Li.

Jan 1, 1973

By F Palkovitz, S Wilson, F Felipe

The management of waste from mining operations is a significant aspect of bringing a mineral commodity to final market. The ore beneficiation process and transport/disposal of waste involves significant consumption of costly resources. A number of options exist to dispose of mill waste on surface and as a backfill material. These range in complexity, risk, capital cost, operating cost and ultimately business performance. This paper discusses the value delivered to a business in using dewatering systems including paste as opposed to conventional slurry tailings disposals. This is illustrated through various case studies and serves to demonstrate how paste can add value and reduce risk to a successful business.

Jan 1, 2009

This paper reviews the commissioning and operation of the process plant at Tolukuma over the past 18 months. The plant treats a high-grade gold and silver ore through a SAG mill followed by a conventional carbon-in- leach (CIL) circuit. Gold is

Jan 1, 1997

By Shoobridge PH

Operating difficulties during 1977 with the Imperial Smelting Furnace operated by Sulphide Corporation Pty. Limited at their Cockle Creek zinc-lead smelter were found to be caused by premature softening of sinter in the upper shaft of the furnace. This soft- ening was shown to be a consequence of raw materials and operating policies which led to unusually high levels of both lead and silica in a sinter of low basicity. A programme of softening tests and micro-examination of a range of sinters established that premature softening occurred when lead and silica increased to the point where a lead-calcium silicate with a low lime content became the major continuous phase in the sinter. This information was used to define a range of compositions which kept the softening temperature acceptably high for furnace operations.

Jan 1, 1978

By Collings P. S, Adair D. L

The Upper Robe (Robe Gorge) deposits occur in Kumina Creek and the Robe River, some 20-40 km upstream from mining operations at Pannawonica. The Gorge Deposits were rec- ognised, mapped and sampled in 1962-3 and re- examined in detail in 1971. Approximately 180 mineralized occurrences were mapped in 1971 on 1:4800 scale and 50 of these were remapped in detail at 1:1200 scale. Eighty cross sections were measured and sampled and 300 geological maps prepared. In addition 88 holes totalling 7388 feet were drilled in three occurrences considered to have the greatest potential. The Gorge Deposits occur in the Robe Pisolite unit which forms thin remnant crusts, bay fillings and occasional cut-off meanders along the edge of the present streams. Less than 50 of the deposits have tonnage potential of one million or more. Consequently exploit- ation of the Gorge reserves must be considered as a very uncertain, long range possibility because the deposits are small and scattered throughout the gorges in the area, thereby necessitating costly railroad spur lines to gain mining access. Grade of the occurrences is extremely variable over short distances both vertically

Jan 1, 1973

By M Stewart, J Vann, A Bu, D Frederickson

The Golden Gift is a recently discovered deep deposit below the main operating areas of the Stawell Gold Mine. At an early stage of the project, diamond drilling was used to define the mineralisation on sections approximately 100 - 150 m apart. The project economics were sensitive to both grade and tonnage. There were consequently two significant risks on resource quantification: risk on tonnage (ægeological riskÆ); and risk on grade (ægrade riskÆ). The degrees of freedom inherent in the geological model were considered to be potentially high because of wide drill spacing and likely structural complexity. To quantify geological risk three geologists familiar with Stawell mineralisation independently interpreted the deposit. This generated three plausible, different geological volume models. Conditional simulation was then used to quantify grade risk. Conditional simulation requires the user to define input statistics (histogram and variogram model) and a geological envelope. Based on global mean grade of an ordered set of simulations, æpessimisticÆ, æmedianÆ and æoptimisticÆ simulation cases were defined. The result was a 3 x 3 risk matrix with geological risk (the three interpretations) on one axis and grade risk (also three cases) on the other axis. An interesting result was that geological and grade risks were of a similar order of magnitude. Therefore a risk analysis of grade by geostatistical methods within a fixed geological model is of limited value, especially if the drill spacing is wide. After completion of this study, with additional drilling, the geological degrees of freedom at Golden Gift reduced substantially. A second Golden Gift risk study used a refined geological model to build a set of simulations to be used in preliminary mine design. A third simulation study in the deeper parts of the Magdala ore deposit, a well-drilled part of the mine with production history, demonstrates that the geostatistical simulation method used at Golden Gift is a robust and useful tool to quantify grade risk.

Jan 1, 2003

By D Sibthorpe

The employment of a tunnel boring machine (TBM) is the default delivery method for the realisation of traffic, utility and primary resource underground space worldwide, with hundreds of kilometres completed safely each year. This is not yet the case for the mining sector in Australia, specifically underground coal mining. The safety advantages of TBM delivery when compared to New Austrian Tunnelling Method (NATM) delivery, or that of drill and blast, remains unrealised.With coal access drifts ranging between 1000?m and 3000?m in length, the construction of these facilities using TBMs could be done in a fraction of the time when compared to current practice. TBM world records currently stand at 435?m/week or 1600?m/month for the 7.0?m to 10.0?m range. Resource owners and developers should embrace the opportunity to deliver access to their orebodies in only a few months, excluding machine assembly and disassembly time.There are challenges in utilising TBMs for construction of Coal access drifts, such as; TBMs generally being bespoke design, maximising capital efficiency for drift development, and geotechnical variances between projects. This paper explores safer and more cost-effective options. This paper also provides detail of how the configuration within a completed drift could be optimised to ensure all site specific needs are met with regard to future use of the drift. The paper also includes descriptions of the engineering solutions that are available for physical and atmospheric challenges specific to coal drift applications and how the TBM manufactures are adapting to the regulatory requirements are also covered.Due to downward pressure on high cost bases and ever increasing safety requirements the popularity of TBMs in the Australian mining sector can be expected to increase and eventually become the default delivery method for coal drift construction, building them cheaper, faster and?safer.CITATION:Sibthorpe, D, 2014. Coal drift construction by tunnel boring machine, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 671–682 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

In Mount Isa voltage and frequency fluctuations caused. by haulage shaft operation gave considerable difficulties with the initial application of Atomic Absorption Spectro-photometry.The methods used to stabilise the various units ' have been described.- Some other difficulties and the means used to eliminate or reduce them together with a-modified burner design are also discussed.

Jan 1, 1963

By J Webb

"It is vitally important in projects where the cut-off grade is low that there is no contamination during the sampling and sample preparation process, both in the ore and the waste zones. Failure to identify contamination could have devastating financial consequences for a project. The use of a variety of blank types is essential for ensuring that contamination is identified and eliminated at every stage of the sampling and sample preparation process. This paper examines an instance where an effective assay quality assurance and quality control (QA/QC) program was able to identify and eliminate a source of significant multi-element contamination in the prefeasibility stages of an open pit project. This examination includes the: evidence for contamination findings of the investigation process of resolving the problem and correcting the data evidence for both addition of metal and dilution through contamination potential impact on the project had this issue not been dealt with. It was through the use of a combination of blank types that the QA/QC process at Mount Isa Mines (MIM) identified a contamination issue at the first crushing phase of sample preparation. Identification of the contamination allowed MIM to stop assaying activities and work with the laboratory to correct the problem. The sampling program could then be continued with no further doubts about the sample preparation process. Contaminated samples were resampled from retained core. With the continuous monitoring provided by the blanks program, it was possible to ensure that only clean results went into the resource modelling data set. CITATION:Webb, J, 2014. When nothing is what you need – the importance of using blanks at all stages of sample preparation, in Proceedings Sampling 2014 , pp 49–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 29, 2014

By Takasaki Y, Ohzeki S, Hotta H

TO measure high temperature properties of blast furnace burdens ( the change of gas permeability accompanied by contraction, soft- ening and melting ) which govern the gas flow and its distribution, a series of experiments were carried out under simulated blast furnace conditions, using sinter, acid pellets and self -fluxing pellets. 1) The high temperature properties are affected by the ore's reducibility ( up to 1000 -1200¦C ), and the composition, and volume of gangue before reduction. Generally, the burde- ns with high basicity ( Ca0/Si02 ), high reduc- ibility and low volume of gangue have good high temperature properties. Good high temperature properties are : a high temperature at which the gas permeability rapidly decreases, a high melting point and a low maximum pressure drop. 2) Using acid pellets, slow-down of red- uction rate occurs around 1000¦C because the pellet forms a dense metallic shell, while its slag core, resulting from a FeO, Si02 and A1203 reaction, has a lower melting point. 3) The addition of MgO sources improves high temperature properties both of sinter and Pellets.

Jan 1, 1980

By Savory P. J

Uranium mining operations commenced at Ranger mine site, Jabiru NT Australia in May 1980. The Ranger orebodies, totalling approximately 110 000 tonnes contained U305 had been indicated by airborne radiometric survey in 1969 and confirmed by drilling the following year. Both diamond and percussion drilling methods were used to define the mineralisation and samples were analysed using a combination of radiometric and neutron activation techniques. Ore reserve estimates were calculated from conventional and geostatistical methods, and following the mining of 15 million tonnes of ore, reconciliations with before mining estimates are well within acceptable industry standards. In-pit grade control employs radiometric techniques including a radiometric truck discriminator built in Australia to mine specification to meet production requirements and improve productivity. Environmental requirements associated with uranium mining are a daily consideration.

Jan 1, 1993

By Morrison RD, Peberdy NJ

Simulator training provides a cost effective method of training operators in both the process and control aspects of a metallurgical plant. The components and requirements of a training simulator are described along with the benefits to be gained from simulator training. A table summarizing some applications of metallurgical training simulators is Given.

Jan 1, 1991

By N Esmaeili, M Saghaeian, L Hosseini, V Sheikhzadeh, R Hejazi

Ore roasting has long been used for beneficiation and assay upgrading of different ores. In this process, which is mainly used for sulfide ores, the ore is heated to a high temperature. More specifically, it is a metallurgical process involving gas-solid reactions at elevated temperatures. Some types of Iron ore are weak in magnetic properties. Hematite, goethite and limonite are classified in this group. Unlike magnetite, which shows strong magnetic susceptibility, these ores are hard to beneficiate through magnetic separation route. Many researches have focused on gravity separation and flotation routes for upgrading these ores and these methods have also been utilised in the industry. One of the methods to whose industrial application less attention has been paid is magnetising roasting in which the non-magnetic iron ore is transformed to magnetite which is further beneficiated through magnetic separation. In this study, magnetising roasting tests have been performed on one goethite sample in order to check the feasibility of using this method for this specific ore in industrial scale. It is worth mentioning that high intensity magnetic separation have been performed on this sample before but the achieved results were not promising. Results have revealed that through magnetising roasting magnetite content of the ore could be increased from 1.7 per cent up to about 25 per cent. FeO content of the feed sample was increased from 1.03 per cent up to around 9.25 per cent. Also optimum size distribution for achieving the best results in magnetising roasting for this sample has been determined through this study. The best results were achieved when the ore size was 0–10 mm. The effect of coal ratio, time and temperature on the process have also be studied. A coal ratio of 5 per cent, time of 30 min and a temperature of 850°C were determined to be the optimum conditions. Finally, the technical feasibility of utilising magnetising roasting for this specific ore has been confirmed.

Aug 24, 2022

The phosphatic overburden of Christmas Island is a lateritic soil and consists dominantly of crandallite and millisite. These minerals are polymorphs of general formula, (Na,K)x Ca2-x (Al, Fe)6 (PO4)4 (OH)10-x (2+x) H2O. Iron occurs only in millisite. Both minerals exhibit similar thermal transformations, dehydroxylating near 600¦C and recrystallizing above 800¦C. Dehydroxylation results in crystal structure collapse but retention of crystal morphology. Ggethite, boehmite and apatite are minor constituents of some-of the phosphatic Soils.

Jan 1, 1971

By Tobin GJ

Testwork carried out in the cooling water circuit at the Yabulu treatment plant of the Greenvale Joint Venturers (Metals Exploration Queensland Pty. Ltd. and Freeport Queensland Nickel Incorporated) since 1980 has resulted in significant improvements to both fouling and corrosion control. At the same time corrosion inhibitor costs have been reduced.Acrylate-type silt dispersants were identified as the most effective means of sediment control in the circuit. An increase in the cathodic component of the corrosion inhibitor coupled with a relatively minor adjustment to water pH has yielded a two to three fold reduction in corrosion rate. It has been established that these lower corrosion rates can be sustained in the face of a 20% reduction in corrosion inhibitor addition rate. Further improvements are indicated with a change of raw water algicide.

Jan 1, 1985

Western Mining Corporation, managing partner of the Windarra Nickel Project are in- stalling a raise-bored haulage shaft and under- ground crushing system at the Mt. Windarra Nickel Mine. The system will be the second of its type installed by W.M.C., the first being in- stalled at the Otter-Juan mine in Kambalda in 1976/77. Both haulage systems became necessary as a result of the increasing production limi- tations, and escalating costs of a deep decline mine. The Windarra haulage system required a single 3m diameter vertical raise drill hole to a depth of 470 metres. Two five tonne skips in balance will hoist crushed ore and mullock to the surface, at a design rate of 200 tonnes per hour, effectively reducing truck haulage leads by up to 50%. It is expected the project will be in full operation by mid 1982 and will enable the mine to achieve an annual production rate of 600,000 t.p.a. by 1983.

Jan 1, 1982

In a high pressure rolls crusher two force components: the pressurising thrust and the rolling force can be measured experimentally. Computer analyses have revealed regular patterns of stress distribution in the confined material between the rollers. Based on the computer analyses and experimental results a one-dimensional comminution model has been developed.

Jan 1, 1995

By Pradhan GK

Blasting is one of the most important operations involved in surface coal mining. The removal of over-burden waste in surface coal mines of India had experienced many improvements in terms of blasting, explosives selection, blast design, equipment selection, deployment. etc. Two case studies of very large surface coal mines have particular importance in their blasting operations. Both these units have been equipped with large capacity excavating machines, hauling units and also have some difficult mining situations. Blasting is done in benches in close proximity to human dwellings and over coal seams developed by underground methods with problems of high wall stability etc, as well. The various steps taken to improve the blasting operations ensure smooth operation of the equipment to meet the targetted coal production.

Jan 1, 1991