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Background BHP Iron Ore Pty Ltd is one of the major iron ore producers in the Pilbara Region of North Western Australia. The company manages three separate joint ventures; the Newman, Goldsworthy and Yandi joint ventures and two 100 per cent owned operations, Yampi and Jimblebar. The Newman operations constitute a mine site at Newman and a 426 km railroad to Port Hedland where there is an ore processing/port site. The Goldsworthy operations currently constitute a mine site at Shay Gap/Nimingarra, a developing mine site at Yarrie, a decommissioned mine site at Goldsworthy and an ore processing/port site at Finucane Island (Port Hedland). The Yandi operations include mining and processing facilities at site and a spur line to join the Newman Hedland railroad. Jimblebar operations are scree and bedrock mining near Newman and include mining, processing and a spur line to Newman where it joins the Newman-Hedland railroad. The Yampi operations constitute a mine/port site at Koolan Island (which is presently being decommissioned). The combined BHP Iron Ore operations produce approximately 46 Mtpa of iron ore. This paper will concentrate on the processes developed and applied for the decommissioning of the Goldsworthy site. The Goldsworthy site is on the northern boundary of the Pilbara Region and adjacent to the western extremity of the Great Sandy Desert. It is located approximately 110 km east of Port Hedland (see Figure 1). The area is generally of low relief with isolated low ranges. The mine site being within the Mount Goldsworthy range area. The geology of the area is essentially Archaean granite with Archaean banded iron formation becoming dominant within the ranges. The chief soils are hard alkaline red soils. The vegetation is essentially shrub steppe with the main hummock grass species being spinifex (Triodia sp). The climate for the region is semi arid tropical. The temperature ranges from a mean low of 15¦C in winter to a mean high of 40¦ in summer. Rainfall is episodic, occurring mainly throughout the summer as a result of tropical depressions or cyclonic activity. The average annual rainfall is approximately 300 mm and annual evaporation may exceed rainfall by up to 2500 mm. Goldsworthy Mining Ltd commissioned the Goldsworthy site in 1965/66. Goldsworthy was the first iron ore operation and associated town site in the Pilbara region. The mine development peaked in 1977 with the town population reaching 1400 people. In 1982 mining ceased and the mining operations were relocated to Shay Gap, 80 km east of Goldsworthy. The Goldsworthy town continued as the base for the railing operations between Finucane Island and Shay Gap. BHP Minerals acquired Goldsworthy Mining Limited in 1990. The population for the town of Goldsworthy at this stage was around 450 people. An assessment of the Goldsworthy site operations concluded that it was uneconomic to continue the operation of the site. The decision was made to transfer the base for railing operations to Port

Jan 1, 1994

By Komosa T

The increase in the proportion of sulphide ore treated by the gold mining industry has led to generally higher oxygen requirements. Additions of pure oxygen, hydrogen peroxide and in some cases calcium peroxide, have been proposed as a means of satisfying the oxygen demand and overcoming the problems from reactive sulphides in the ore. Current oxidant addition options and practice are reviewed.Laboratory oxygen demand tests are reported for a suite of ores to show some of the effects of pH and preaeration.Laboratory leach tests at high and low dissolved oxygen levels are reported on two of the ores with higher oxygen demands, and the results are assessed in terms of gold leaching kinetics, ultimate gold extraction, and cyanide requirements.

Jan 1, 1992

During the past 18 months a rock mechanics project has been in operation at Renison Limited. The project was established to identify and investigate key problem areas that would affect future production at the Renison mine. An in-house approach was adopted, using shall compact equignent, to investigate ground behaviour. Information on the rock stress field was considered to be particularly important for an understanding of ground behaviour. A high horizontal stress component exists, which enables large flat dipping spans of hanging wall to be opened up, with support being provided by post pillars. The amount of support provided by these post pillars has been found to be low.

Jan 1, 1982

By M Nehring, M Kizil, P Knights

Mining and beneficiation can be described as sequential processes of separation of valuable minerals from waste. There is a great deal of interest in how the industry can be more effective – and efficient – with these processes. In particular, many mining companies are looking towards digital technologies to improve precision mining practices; that is, the targeted identification and separation of valuable ore from waste during the mining process. Greater precision will help unlock the value in many complex orebodies that are currently considered Tier 2 or 3 deposits. CITATION: Knights, P, Kizil, M and Nehring, M, 2018. Selection of precision surface mining methods for complex metalliferous orebodies, in Proceedings Complex Orebodies Conference 2018, pp 31–34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

Geological hazards such as faulting, basement ridges, and zones of "thin" (

Jan 1, 1998

By H Nikraz, E Jamieson, D Cooling

The use of red sand as fine aggregate in concrete manufacture has been investigated as well as the use of fly ash as a cement replacement. The experimental work consisted of casting various concrete mixes including a control and comparing standard properties. Properties tested included compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, water permeability, chloride diffusion, pH dependence leaching and particle morphology. The results show that the concrete strength is not significantly affected when natural sand is replaced completely with red sand. The durability tests indicated high water permeability and high chloride diffusion due to the porosity of the red sand concrete, likely due to the low slump value. Leaching tests did not exceed New South Wales EPA guidelines.

Jan 1, 2006

By Yan D. S

The removal of antimony from a refractory gold-bearing stibnite ore by roasting and selective chlorinating roasting was investigated. The influence of roasting temperature, roasting time, roasting atmosphere and type and amount of chlorinating agents on antimony removal were studied. The laboratory studies carried out included roasting tests of 4 g samples in a laboratory rotary kiln, followed by 400 g samples roasted in a fluidised bed. The test results revealed that antimony was efficiently removed by roasting at temperatures over 800¦C in a nitrogen atmosphere. The most efficient volatilisation of antimony was achieved with the addition of ferric chloride at temperatures between 350-600¦C.

Jan 1, 1995

By Quast K. B

Laboratory batch rod and ball milling tests were conducted on samples of Heavy Medium Separator (HMS) sinks from Renison Tin Limited. The product size distributions for this heterogeneous material were very different to similarly sized homogenous material previously reported by the authors. The effects of pulp density on product size distributions were only evident at pulp densities greater than 80 per cent solids. At high solids density, the major weight distribution product peak fell and broadened indicating less efficient breakage, particularly for rod milling. Tin distribution in the ground products was also affected by pUlp density, and there was always less cumulative per cent tin than cumulative per cent weight, ie there was no tendency for cassiterite to slime down to 10/lm.

Jan 1, 1995

By Marquez W

Trace fossils have been found in Bolivian Silurian sediments in "La Iumhre" area close to La Paz-Bolivia.Tracks, are good indicators of depth and environment. A detailed study of the ichnogenus is made.The depth and environmental deposits are analyzed to determine the facies. It was shown that the trace fossils of Silurian sediments in La Paz belong to the Zoophvcos and Nereites facies.

Jan 1, 1990

The Northwest Territories (NWT) of Canada has emerged as a major new province for diamond mineralisation in less than three years. This is primarily the product of a diligent search in the form of a scientifically based exploration effort. However other factors, including positive aspects of the business and the legal environment have also been identified as assisting the exploration process. In my view these have increased the likelihood of diamond mining becoming a major new industry for Canada. The supportive role of various government agencies has been important. In addition, the character of many of the joint venture deals that have been done has provided an attractive setting for the capital intensive evaluation and development work that is now required to bring the diamond discoveries into production. Perhaps of equal importance is that with the recognition that is being given to the success of the NWT diamond ventures, Canadian explorers are continuing to attract new risk capital for further exploration. This paper attempts to model and quantify the probability of exploration success translating into successful mine development.

Jan 1, 1994

In 1997, the Australian coal industry through Standards Australia committee MN-001 Coal and Coke recognised the need to produce a Standard giving some instruction on how to inspect and audit mechanical sampling systems. A Guide was developed by sampling subcommittee MN-001-04 and in 1999 the Standard was released as AS4264.5 æGuide to the Inspection of mechanical sampling systemsÆ Coal and Coke. Since that time the author has assisted with other committees in developing the Guide for other commodities such as concentrates and a generic standard for particulate materials. (AS4433.6 released 2000). The Coal and Coke guide is also currently a work item for ISO Standards. This paper is focused primarily on auditing and inspection procedures for coal mechanical sampling systems. It highlights the need for at least a three level inspection protocol where the operators manning the system maintain operational checks, the operators are regularly supervised by the company managing the system and once per year an independent auditor inspects the whole system to ensure compliance with design and standards. It does not cover short- and long-term maintenance of individual systems. With companies already certified to the ISO9000 series, this guide forms the framework to bring the operation and inspection of their mechanical sampling systems into line with these principles.

Jan 1, 2005

Drill and blast excavation in underground mining and. civil engineering projects has grad- ually given ground to mechanical boring of tun- nels, shafts and raises during the past twenty years. The use of.boring equipment must today be considered significant and wide spread al- though comprising only a very small percent of total underground excavation. The encroachment of mechanical boring into the domain of blast- ing has been by slow incremental advances. There have been few, if any major breakthroughs in this development, and none can be foreseen in the next decade. After 1990 it is possible that scientific. development will provide some form of breakthrough in rock breaking, but this is so uncertain that it should have little relevance to planners in the 1980's. A more near term view of the future, con- centrating on the next five to ten years, has lead to the conclusion that significant im- provements will be seen in tunnel borers for poor ground conditions. A universal machine will be developed that converts from a dry hard rock machine to a closed slurry type machine for passing through fault zones with unstable crushed rock and water. Two other machines have been described as alternate designs for tunnelling in squeez- ing ground conditions.

Jan 1, 1981

Revised throughput rates, as a result of current mining methods and tight controls on mine dilution, have dictated a change in metallurgical philosophy at Renison Limited. Emphasis on throughput capacity increases has altered to a reduction in circuit complexity and operating costs. Extensive surveys of the gravity and cassiterite flotation circuits led to several plant modifications between August 1989 and March 1990. The coarse and fine gravity retreatment roughing tables were by-passed, the coarse gravity retreatment roughing tables were re-commissioned, the cassiterite flotation rougher capacity expanded and the gravity regrind cyclones re-configured.

Jan 1, 1991

The Iron Prince orebody occurs within the Lower Middleback Jaspilite Horizon of the Middleback Group and consists of hematite within host rocks of jaspilites and schists. The ore was probably the product of leaching of silica from jaspilites and replacement by iron, concentrations occurring in suitable structural traps. The narrowness and the presence of extensive dolerite amphibolite dykes within the orebody make it essential to operate a grade control programme in advance of the faces. Information from drilling is drawn up on bench plans, step plans and impurity overlays, and these serve both in day to day production planning and in long term planning. Mining is done selectively by open-pit methods and blending conducted by keeping at least three faces of different grades of ore open at any one time. No stock piles of ore are kept for blending, but contact ore, contaminated ore and enriched material are dumped for later beneficiation.

Jan 1, 1971

Blasting is a common practice in mining whereby solid rock is fractured, using explosives, to a more manageable size. The effectiveness of blasting influences a number of downstream activities such as shovel digability, crusher throughput and mill throughput. As the cost of explosives is relatively low compared to milling costs (mainly due to power consumption), blasting practices can be optimised so that the downstream processes are made more efficient, and an overall cost saving made. This is the basis of the Mine to Mill approach. The effectiveness of the blasting is influenced by two main factors, the blasting practices used (eg explosive amount and type) and the geology of the area. As the geology cannot be altered, the blasting practices must be refined to create optimum blasting. Kalgoorlie Consolidated Gold Mines (KCGM) Fimiston operation, located in the heart of the Kalgoorlie Goldfields is the largest gold mine in Australia. Mine to Mill at KCGM has had varied success, with initial positive indications being lessened by a number of factors, including the increase in the amount of voids.

Jan 1, 2003

By Heidecks C

Sub-level stoping with consolidated rockfill is the main method for mining steep dipping baryte and fluorite veins in Germany. Drifting is fully mechanised using drill jumbos, LHD units and shotcrete support. Stopes have heights up to 50 m with sub-level distances up to 15 m. Winning of the pillars between sub-levels is done by longhole blasting in slices of 3-5 m length on strike. Mucking is done on the lowermost level by LHD units. After each blast rockfill with binder (cement and/or fly ash) is dumped into the scope from the uppermost level. Economic success depends on both geological and technical parameters and factors, eg vein thickness and dip, ore grade, size and distance of sub-level drifts. Of particular influence are ore loss in pillar winning and dilution both in drifting on vein and in pillar mining. A comprehensive computer program has been developed for calculating the total cost per tonne run-of-mine ore respectively per tonne of concentrate for a single stope. The cost model includes development, longhole blasting, mucking and haulage to the mill, milling and ventilation. All costs (labour, energy, supplies, maintenance, depreciation and capital cost) are taken into account. Dilution and recovery are both considered. The program can be used to estimate the cost of mining a particular stope. It can also be used to investigate the influence of relevant parameters and factors on the economic result. By this way it should be possible to optimise the technical design of a stope.

Jan 1, 1995

The southern portion of the Swan Coastal Plain, a geomor-: phological element formed since late'Tertiary times, contains commercially exploitable accumulations of ilmenite, zircon, rutile'and monazite associated with a series'of raised'shorelines. The:location'of the deposits is controlled by a locally outcropping*Archaen-granite/granulite complex and a sea':current pattern'determined'by'local geography and a prevailing wind direction.'-A progression from medium. to high titanium ilmenite is'evident parallelled by. progressive leucoxenisation as the age of the deposits increases. Variation's in trace element content accompany this process. Circulating groundwater has caused vertical mineralogical variations within-individual deposits and' by p'ecipitation of iron has formed layers of hardpan. The economic sig- nificance''of the Geographe--Bay deposits is'briefly discussed,

Jan 1, 1964

By Daniels E. J, Morgan W. A

In response to the increase in consumption of galvanised steel for automobiles in the last decade and the problems associated with remelting larger quantities of galvanised steel scrap, a process is being developed to separate and recover the steel and zinc from galvanised ferrous scrap. The zinc is dissolved from the scrap in hot caustic using anodic assistance and is recovered electrolytically as dendritic powder. The dezinced ferrous scrap is rinsed and used directly. The process is effective for zinc, lead, and aluminum removal on loose and baled scrap and on all types of galvanised steel. The process has been pilot tested for batch treatment of 900 tonnes of mostly baled scrap. A pilot plant to treat continuously loose scrap, with a design capacity of 48 000 tonnes annually, has been in operation in East Chicago, Indiana since early in 1993. The first 450 t of scrap degalvanised in the pilot plant have residual zinc below 0.01 per cent and sodium dragout below 0.01 per cent. Use of degalvanised steel scrap decreases raw materials, environmental compliance costs, and opportunity costs to steel- and iron-makers. Availability of clean degalvanised scrap may enable integrated steel producers to recycle furnace dusts to the sinter plant and EAF shops to produce flat products without the use of high quality scrap alternatives such as DRI, pig iron, or iron carbide. Recycling the components of galvanised steel scrap saves primary energy, decreases zinc imports, and adds value to the scrap. The quantities of zinc available by the year 2000 from prompt and obsolete automotive scrap will approach 25 per cent of zinc consumed in the major automotive production centres of the world. Zinc recycling from galvanised steel scrap, either before or after scrap melting, will have to be Implemented.

Jan 1, 1993

By Laing W. P

Sedimentary structures are described from the WiIlyama Complex, New South Wales. Their presence confirms lithological layering within the metasediments as bedding. These primary structures occur not only in low grade rocks as previously reported by other workers, but also in areas of medium and high grade metamorphism.Sedimentary structures include graded beds, cross beds, ripple marks, and ball and pillow structures.The observed parallelism of the early schistosity and bedding in the Broken Hill area has previously led to the idea of transposition by isoclinal folding.In the areas mapped, small scale transposition is precluded on the basis of1. uniform facing of sedimentary structures over wide areas, and2. the existence of large areas in which the early schistosity is oblique to bedding.

Jan 1, 1975

By M Littlefair, D Gribble, R Rounsley, I Te

Low-density explosives (LDE) have applications where the explosive properties of ANFO are not well matched to the rock. In particular, rocks that are of low strength and/or well fragmented in situ. Dyno Nobel Asia Pacific (DNAP) has developed a new LDE, BlastLiteTM, which can be used as a cost-effective replacement for ANFO with excellent detonation characteristics. The product is based on ANFO with the addition of a bulking agent. The key to the product lies in the ability of the bulking agent to form a homogeneous blend with ANFO without the need for any emulsion matrix to bind the product together. This results in an LDE of low cost and high weight strength compared to existing commercial LDE products. The product has been trialled extensively and has proven to provide results that are equivalent to, and often better than, ANFO with reduced powder factors. This paper details the laboratory development and results of field trials for DNAPÆs LDE solution: BlastLite.

Jan 1, 2004