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Within the Mt Whaleback open cut mine the integrity of the final pit wall is achieved through careful rock slope design, use of rock reinforecement technology where marginal stability exists and use of controlled blasting techniques and excavation practices. By reducing the effective density of ANFO explosive within blastholes to around 0.2 glcm', and developing standard blast pattern designs for various rock types, blast damage to pit walls has been minimised. Accurate geological prediction is necessary for optimum blast design. Controlled blasting is undertaken where blasting occurs within 90 m of the designed final batter crest and hole by hole assessment of final limit blast patterns is undertaken before pattern charging. Shovels and trucks remove the bulk of blasted and dozed rock material, but due to the mine's variable pit wall slope configuration, bulldozer excavation of some critical design batters has been successfully Implemented.

Jan 1, 1986

By Rowe J

The case study is based on the largest ore deposit at Mt. Lyell; the Prince Lyell deposit, comprising a regular lensoid mass of dissemina- ted and vein pyrite-chalcopyrite mineralisation. Reserve estimation employs conventional techniques, based on diamond drill hole and relevant development sampling data. Probable ore reserves are estimated using the contouring (isoline) method an longitudinal projections for ore thickness and accumulation (m %Cu) at a '0.8% Cu' cutoff. Final stope and pillar res- erve estimates (proved ore) are derived from designed ring tonnages and contoured accumula- tion for individual mining units, following more intensive sampling. Systematic grade control procedures have been adopted and individual stopes and pillars reconciled against mill production. The proved ore estimates have been found to com- pare favourably with the reconciled production.

Jan 1, 1979

By H Mansouri, M A. Ebrahimi Farsangi, F Faramarzi

A blast fragmentation model is developed based on the gamma function to describe the run-of-mine fragmentation distribution. The model presented is aimed to benefit from simplicity in application and also to be efficient in description of the fine to coarse part of the blast rock fragments. In fact, the gamma based model (KC-KUM), gives a unit distribution curve, which is made up of two separate equations, covering different fragment sizes in the muck pile. The generated values of the fines to central part of the equation and the central to coarse part of the equation are connected at the 40 per cent grafting point. For validation, eight production blasts, which were specially designed for this purpose, were carried out at an iron ore mine (Jalal-Abad iron ore mine/Iran). Results achieved by KC-KUM and two of the most well-known models. Kuz-Ram and Swebrec, are compared with measured data. Moreover, to assess the models’ efficiency in presenting the best distribution curve, a Logarithmic error method is chosen. Based on the achievements. KC-KUM has the least deviations by the least absolute log error of 0.52, whereas the values obtained for the Swebrec and Kuz-Ram models were 0.79 and 1.34 respectively. Furthermore, the models were applied to predict X80 for 12 production blasts carried out at Gol-e-Gohar iron ore mine/Iran. These predictions were compared with the results from these trials. The coefficient of determination (R2) and root mean square error (RMSE) are calculated. Consequently, the highest R2 was obtained for KC-KUM at 0.837 with the least RMSE of 11.31. On the other hand, R2 and RMSE are equal to 0.832 and 20.19 for Swebrec; and 0.813 and 19.75 for Kuz-Ram respectively. The results obtained suggest the superiority of the KC-KUM model over the other two models in assessment and prediction of blast fragmentation in a reliable way.CITATION:Faramarzi, F, Ebrahimi Farsangi, M A and Mansouri, H, 2015. Prediction of rock fragmentation using a gamma-based blast fragmentation distribution model, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 685–692 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By S Servant, T J. Bidwell

Paste backfill technology is gaining rapid acceptance in the Canadian mining industry. The authors were able to work on four different mining sites employing paste technology in their operation. In each site the paste backfill is prepared with very fine tailings containing significant amounts of sulphur minerals. The research program involved laboratory testing on samples prepared in the laboratory, on control samples obtained at the backfilll plant during pouring into the stopes and on core samples obtained from drilling in backfilled stopes. The laboratory testing provided detailed knowledge of the mechanical behavior of the paste backfill. The need for a means of measuring the in-situ mechanical properties of the backfill became clear. A review of various trials published in literature and an evaluation of available technology suggested the Cambridge Self-boring Pressuremeter. A first field campaign confirmed the efficiency and dependability of this instrument leading to the conclusion that it offers a very good method for the in situ measurement of paste backfill properties.

Jan 1, 1998

Exploration by Cyprus Minerals Australia Company (formerly Amoco Minerals) has successfully outlined significant Au-(Cu) mineralisation at Starra, 150 kilometres south-east of Mt. Isa. Mineralisation is stratabound and localized in deformed and metamorphosed ironstones (B.I.F?) and iron-oxide bearing schists of the mid-Proterozoic Staveley Formation. Over 90% of the presently outlined potential ore occurs in 4 discrete zones within a strike length of 3.5 kilometres. The inferred geological resource in these zones is approximately 6 million tonnes grading 5 grams per tonne gold and 2% copper. Roughly half of this is open-pittable, but more rigidly applied mining criteria will probably reduce the exploitable tonnage. Detailed infill drilling is in progress and a pre-feasibility study has commenced. The joint venture partners, Cyprus Minerals (75%) and Elders Resources (25%) expect to make a development decision by the end of this year.

Jan 1, 1986

This paper discusses the recently com- pleted TBM-driven pressure tunnel at the Sand Bar Hydroelectric Power Project. The Sand Bar Project is a diversion scheme situated on the middle fork of the Stanislaus River in the Western Sierra Nevada, California, U.S.A. As part of the project, a 5.6 km long and 3.71 m diameter unlined pressure tunnel was bored by a Jarva TBM at the average rate of .37.5 m/ day. This report deals with construction aspects of the tunnel, including TBM performance, lining design, and remedial support measures. Correlations between TBM performance, geologic conditions, and rock properities are made, and the Contractor's mode of operations are discussed. Advance rate prediction, and the impact of these excellent advance rates attainable in hard rock using the new machines are discussed.

Jan 1, 1987

During the 1950's there was a flurry of activity on the design of main ventilation shafts for mines. More recently, a new ana- lysis was commissioned in relation to the multi-shaft, nuclear waste isolation facili- ties currently under design in the United States. This paper presents the major find- ings of that study and should prove of value as a reference in the design of proposed new shafts. An overview of mine shaft resistance introduces the effects of the shaft walls, fittings, conveyances and shaft stations. Each of these is analyzed in turn. A com- pletely new technique is described, which facilitates the estimation of wall resis- tance. The effect of size of a conveyance is quantified and shown to be dominant when the cage occupies more than 30 per cent of the shaft cross-section. The dynamic effects of a moving conveyance are also analyzed.

Jan 1, 1988

By Penny T. G

BHP Diamonds and their joint-venture participants DiaMet Minerals, Chuck Fipke and Stewart Blusson are currently developing Canada's first commercial diamond mine in the arctic barren lands of the Northwest Territories (NWT) of Canada. The paper reviews the early history of the project leading up to the discovery of the first kimberlite pipe in September 1991, diamond exploration techniques and the subsequent advanced exploration and development work carried out at the site. In many aspects, this exploration work represented a development project in itself. Coinciding with the advanced exploration work, the project team prepared an Environmental Impact Statement (EIS) and went through federal review of the project at the highest level. External affairs strategies regarding the federal review and aboriginal land claim issues were crucial components to the approval process. Upon approval in principle by the

Jan 1, 1997

By Green GR

Description of two methods developed at Sulphide's Cockle Creek Plant as part of a site energy reduction program. The two case studies are:

Jan 1, 1985

In late 1984, Council of the Australasian Institute of Mining and Metallurgy accepted a proposal to establish a Mineral Heritage Committee. This was to be involved in matters relating to mineral heritage-its recording, its preservation, and the acknowledgement that it can be of use to the mineral industry in the future. The Committee was established to ensure that all of the disciplines of our profession were included and that, so far as possible, all of our country as well as those countries of the Southwest Pacific Basin were represented. Some work has been commenced to bring real- isation of the importance of the heritage of our mineral industry to the forefront of the commu- nity's interest. There is not a state in this country and the Southwest Pacific where the mineral industry has not at various times proved to be the basis of community development.

Jan 1, 1987

By E Ferrow, R Herbert, M E. Malmstr, M Fuchs

The study of microbial sulfide oxidation and oxidation rates of tailings requires the use of sterile control samples in laboratory experiments for comparison purposes. The need for sterile tailings sand is also apparent in the study of microbial communities and processes. This study compares six different methods with regard to sterilisation efficiency and investigates chemical and mineralogical changes in the samples as the result of sample treatment. In addition, the effect of sterilisation on mineral weathering rates is also studied. The efficiency of the different methods with regard to sterility is estimated by most probable numbers (MPN) of both sulfur and iron oxidising bacteria. The sterilisation methods that were compared are: washing with sterile water, washing with ethanol, applying antibiotics, repeated heating to 70¦C, autoclaving, and γ-irradiation. There are several possible drawbacks with the different methods, including the risk of an applied chemical acting as a substrate for micro-organisms in the system, and the risk of altering the tailings. The results show a substantial difference in sterilisation efficiency between the treatments. For example, autoclaving, repeated heating, ethanol and irradiation efficiently kill micro-organisms, rendering an undetectable amount of bacteria after one month of incubation, whilst washing with water exhibits virtually no microbiological effect, with a bacterial content comparable to the control. The use of antibiotics for sterilisation ranks intermediate: the lag-phase was twice as long in the antibiotics treatment compared with the controls. X-ray diffraction, optical and electron microscopy, M÷ssbauer spectroscopy, and mineral magnetism indicate no significant change in the bulk mineralogical composition. However, X-ray photoelectron spectroscopy analyses show that with some of the treatments, sulfides are partially oxidised, as indicated by the formation of sulfate and partially û oxidised sulfur species at the tailings surfaces. Aerated batch weathering experiments performed on sterilised tailings samples and untreated controls indicated that while the initial rates of element (S, Fe, Cu, Zn, Mg, Na, K, Ca) release may differ between the samples, over the course of ~100 days of experiment at pH 2 and room temperature, the rates declined toward a similar value for all samples. To conclude, there does not appear to be one perfect method for tailings sterilisation. Autoclaving and heating damage the mineral grain structure and oxidise the sulfide surfaces. Ethanol, antibiotics and rinsing greatly alter the pore water chemistry through the washing procedure. In addition, ethanol and denatured antibiotics might serve as a substrate and also, in the case of antibiotics, adhere to mineral surfaces thus obstructing chemical reactions. Irradiation seems to be the preferable method on an overall basis, although the formation of surface Fe3+ was suggested by M÷ssbauer spectroscopy.

Jan 1, 2003

By Bruce P, Luyendyk

The South Island of New Zealand comprises a collage of distinct tectonostratigraphic terranes. Some tectonic models predict that these terranes formed on or near the margin of Gondwanaland. However, geologic evidence suggests that some of these terranes may be exotic. Over 400 samples from 30 sites were collected from the Brookstreet terrane within the Takitimu Mountains. The section includes the early Permian Takitimu Group and the late Permian White Hill Intrusive Suite. Over 80% of the rocks show a partial or complete regnetization in the present field due to recent acquistion of VRM. Although some remagnetization of the Takitimu Group occurred during the emplacement of the White Hill Intrusives, both early and late Permian direction have been isolated. These directions indicate a mid-latitude origin for the Brookstreet terrane, and suggest a strong clockwise rotation between early and late Permian time. A published paleomagnetic result from the younger, but related, Murihiku terrane suggests that the Brookstreet terrane was sutured to the margin of Gondwanaland by the late Triassic, or that the Brookstreet and Murihiku are two distinct terranes.

Jan 1, 1987

By Doig ID, Phillips HR

As a prelude to studying the sorption desorption and permeability behaviour of coal cores in a triaxial stressing rig using sorb- able gases, the air permeability of typical cores was measured. Lump coal samples were obtained from three gas-troubled collieries in Queensland and New South Wales. These were cored in the laboratory and a simple laboratory permeameter employed which accepted 38 x 40 mm cores in a thick rubber sheath. Air pressure of 500 kPa was applied outside the sheath to provide suitable sealing between the rubber and the coal. Differential driving pressures up to 100 kPa were employed and the air flow measured by displacement of water columns in inverted graduated cylinders. Flow measurements accurate to + 2% could thereby be achieved. Coal lumps were cored both parallel and perpen- dicular to the bedding plane, and were observed prior to measurement for any notable features, in particular for the presence of fissures. Between samples an overall variation of from 100 milliDarcy was found in Appin, Westcliff and Leichhardt coals. Significant variation was observed both from section to section of a core and between regions of a

Jan 1, 1982

Qualitative measurement of respirable dust in metal mines is limited and an example of this is demonstrated at Northparkes Mine, where operational experience was sought for measuring dust standards and identifying exposure limits. However, relying on operational experience has limited value due to variation in observations from person to person and is based on visible dust (which is larger in size than respirable dust). However, with sophisticated dust measuring equipment, like the real-time aerosol monitor, dust concentrations can be accurately measured and recorded concisely. Research conducted as part of a collaborative agreement on behalf of Northparkes to launch an occupational dust monitoring program was implemented on the mine site. To form the basis of this research, it was hypothesised that no proper dust measuring testing at the mine site had been adequately identified. In addition, existing occupational hygiene monitoring programs did not adequately quantify employee exposures to these hazards. This project will outline the results of an occupational dust monitoring program, hence greatly improving the capacity to quantify the health risks posed to employees.

Jan 1, 2008

This paper discusses recent ore reserve methodology at the Woodlawn base metal Mine in New South Wales. The ownership of the Mine changed hands in 1987 and a number of revisions to ore reserve practice were instigated by the new operators. While the overall modeling and calculation procedure remained essentially unaltered, the modifications and revised assumptions significantly increased the ore reserve. While general ore reserve procedures are discussed in this paper, it is the impact of these changed assumptions on the reserves which is our main focus.

Jan 1, 1990

The transition from low stress to high stress conditions is a challenge eventually faced by most mines in Australia that extend to depths greater than (generally) about 1000 m. In areas with strongly adverse 'stress versus depth' gradients, such as some parts of Western Australia, significant stress-related problems have occurred at depths as shallow as 300 m below surface. The actual depth at which the 'transition' occurs is a function of the local pre-mining stress field, the strengths of the various rock types hosting the deposit and the layout and sequencing adopted in the mine. Stress-related damage can result in increased support costs, and delays associated with rehabilitation and disruption to production. In the worst case, where strong seismicity and associated damage occurs in active mining areas, 'exclusion' zones and 're-entry' protocols may be required. These can severely disrupt production. A key aspect of managing the transition is the recognition of the onset of stress-related ground behaviour. Damage mapping can be used to develop understanding of the relationships between mining activities and the local and regional response to them. Carefully documented case histories provide a basis for calibrating numerical models. This paper discusses some of the typical styles of ground behaviour observed in higher stress conditions in underground mines. A simple damage classification scheme is described to assist in 'damage mapping' of mine tunnels. An example of damage mapping is presented to illustrate an approach commonly used for recording stress-related damage.

Nov 25, 2010

By M Ben, P de Donato, M Kongolo

The extensive literature on sulfide flotation indicates that pyrite poorly floats under alkaline condition. Xanthate concentration has a positive effect on pyrite flotation, but above a pH of 11, pyrite seems to be strongly depressed, independently of the concentration in xanthate. In this investigation, aeration and xanthate concentration effects were studied for pyrite flotation conditioned at pH 11 with lime. Results presented in this paper include surface infrared analyses and pulp chemistry measurements which have showed that aeration had a dual effect on pyrite flotation. It induced pyrite surface activation by oxygen, and oxidation of ferrous iron to ferric hydroxides or oxyhydroxides species. It also favoured dissolution of CO2, leading to calcium carbonate precipitation and adsorption onto pyrite surface. Both CO2 dissolution and ferrous oxidation generated protons and decreased pulp pH. Pyrite flotation was observed to be effective with a statistical monolayer of xanthate that could be adsorbed as mixture of dixanthogen and metal-xanthate complex. Non-floated fractions showed high amounts of carbonate, and presence of hydroxyl iron sulfate (Fen(OH)m(SO4)p, xH2O) which have inhibited the hydrophobicity effect of adsorbed xanthate. Environmental desulfurisation could be improved by aeration control causing pyrite oxidation and pH decrease to reach optimal flotation condition with a relatively low xanthate concentration.

Jan 1, 2005

By James D, Dawson N

The alternate mineral dressing tech-niques for the production of ilmenite roaster feed from heavy mineral concentrate and the reasons for the selection of wet high intensity magnetic separation (WHIMS) at Richards Bay Minerals are outlined.Initial flowsheet studies were under-taken using laboratory scale equipment followed by on site pilot testing. Flowsheet development culminated with an extensive test programme conducted at Readings of Lismore in 1975.

Jan 1, 1986

By T Tan, C P. Holmes, C E. Hartford

Transportation of iron ore from the mine to the plant is critical to business success. Ore from the mine may have to be transported across states, countries and even continents to get to the processing plant or export facilities, and ultimately to the client. Numerous transportation steps may result in potential logistical difficulties. Companies are continually seeking ways to increase production rates, decrease delivery times and reduce operating costs. Transportation cost is a major component of the total cost of mining iron ore and therefore requires effective use of transport systems.Bottlenecks in iron ore transport systems, due to material handling issues, can result in loss in profit in the order of millions of dollars per hour. Bottlenecks can be seen anywhere in the transport system where the desired flow rate cannot be achieved. These bottlenecks occur for various reasons such as increasing throughput in a transport system originally designed for a lower throughput resulting in plugged transfer chutes, changing material characteristics (eg finer material, increased moisture content), changing to a new type of material or blend that again alters handleability, or changes in operational philosophy due to equipment availability or process utilisation.Stockpiles may have limited live capacity such that an adequate amount of ore may not be readily reclaimed when required (eg to fill a complete train’s railcars). In bins and hoppers, material may discharge through a central flow channel resulting in the formation of a stable rathole, which can then collapse causing material to flood the downstream system and cause significant downtime for clean-up (eg railcars beneath train load outs). In transfer chutes, bottlenecks can be caused by pluggages or downtime required for the change-out of liners due to excessive wear. In ship loading, long settling or de-aeration time, or material exceeding its transportable moisture limit (TML) may result in further bottlenecks. These bottlenecks all have associated costs because of the need to address their causes and because of the lost opportunities for throughput.This paper will discuss how bulk material technology and proper understanding of material flow characteristics can be applied to mitigate bottlenecks. It will discuss how to predict potential bottleneck locations through a scientific method of analysis and evaluation to determine if an increase in throughput of an existing transport system is possible, as well as whether or not a new material will flow reliably through an existing system.CITATION:Hartford, C E, Holmes, C P and Tan, T, 2015. De-bottlenecking iron ore transportation from mine to plant, in Proceedings Iron Ore 2015, pp 393–398 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

The object of this paper is to show in some detail the mining challenges that have been presented and overcome during the successful development of the main exhaust ventilation drive that will service the Ballarat East mine during its 20+ year lifespan. Topics to be discussed in this paper include the ground support regimes employed, the ground conditions encountered during construction, how the heading was recovered after falls of ground and the effectiveness of geotechnical probe drilling at Ballarat.

Jan 1, 2006