Search Documents

The thick coal seams of the South Maitland field are the only ones in New South Wales which have been worked extensively to heights beyond 3.8 m (nominal "thin" seam height). Under shallow cover only minor difficulties were experienced in developing first workings but later the widespread occurrence of incidents of spontaneous combustion and the growth of "creeps" extending over large areas gave the field its own peculiar problems. As the mines have driven under deeper cover extreme difficulties in forming development roadways have been experi- enced. Various methods have been adopted in an attempt to overcome the problems of the field.

Jan 1, 1976

BHP Billiton Mitsubishi Alliance, or BMA, is AustraliaÆs largest coal miner and exporter, and is currently responsible for around a quarter of AustraliaÆs total annual coal exports. BMA and its predecessors have been part of the Queensland mining scene for around 40 years, developing world-class mines, a port, overseas markets, and an international reputation for quality and reliability. From its production base in QueenslandÆs Bowen Basin, BMA produces a broad suite of coals which are supplied to 73 customers in 24 countries. BMA was formed in June 2001 as a partnership between BHP Billiton and Mitsubishi Development Pty Ltd, under which the two companies share equal ownership and management of eight Central Queensland coal mines û Goonyella Riverside, Broadmeadow, Peak Downs, Saraji, Norwich Park, Gregory, Crinum and Blackwater û and the Hay Point coal export terminal near Mackay. This case study focuses on Peak Downs Mine, which was the second largest open cut mining operation to be developed in the northern Bowen Basin for the original CQCA Joint Venture. The first coal was mined in April 1972 and today, Peak Downs has a production capacity of over nine million tonnes of coking coal per annum. The mine is located 30 km south of Moranbah and 195 km south west of the Hay Point port facilities. Coal is mined by open cut mining methods using six draglines and two truck/shovel stripping fleets for overburden removal. Coal seams are mined using excavators and front-end loaders and 210 tonne capacity coal haulers.

Jan 1, 2007

Polyacrylamide flocculating agent has been used in the Leaching Division of the Risdon Works of the Electrolytic Zinc Co. of Australasia Ltd since October, 1960. Since the introduction, the.: number of thickeners in use in the continu-ous thickening stage has been reduced from eight to three; there has been an increase of 25% in throughput and a reduc-tion of solids in.:thickener overflow from 3-4 gòpòl . solids to 0.5 g.p.l. solids. Reagent addition has been at the rate of 0.25. lb SEPARAN, NP10 per ton solids.Additionally there has been a gain of 3% in current efficiency as the direct result of the addition of SEPARAN NP10 to purified cadmium sulphate solution prior to electrolysis for cadmium metal. A smoother deposit has resulted and it has been possible to increase deposition time between strip-pings from 47 to 71 hours. However, there has been a slight increase the lead content of the cadmium-metal produced.

Jan 1, 1963

By Chappell BW

A zone of northwest trending dykes extends for over 600 km in the hinterland from Cairns to Mackay. In sate regions the zone is up to 120 km wide. Figure 1 shows their approximate extent, compiled from published regional maps and from specific studies in more limited areas : Palm Islands, Cardwell Ranges, Jourama Falls, Townsville area and Burdekin Delta. The context of the dyke swarm is the Tasman Orogenic Zone, the region of Eastern Australia conprised of Palaeozoic metamorphic, sedimentary, volcanic and plutonic rocks which has experienced a complex history and evolution. In the Whitsunday region, the Tam-an Zone also involves Cretaceous volcanism and plutonism. Geological relationships indicated a wide span of ages for the intrusions in the dyke, swarm zone. They intrude a range of volcanic and sedimentary rocks, and in some areas plutonic rocks. Older dykes, apparently part of the same regional swarm are intruded by sate of the granites.

Jan 1, 1987

By S Miller, R Smart, J Thomas

Single-addition and sequential net acid generation (NAG) experiments were carried out on natural and prepared samples with varying contents of organic matter and pyritic S. Results show that carbonaceous matter can produce significant quantities of organic acids during peroxide oxidation in the NAG test, which leads to overestimation of acid-forming capacity and misclassification of benign samples as potentially acid forming (PAF). Organic matter effects were most pronounced in samples with low S (less than 0.5 per cent) and total organic carbon (TOC) contents of greater than seven per cent. The single-addition NAG test will tend to overestimate acid potential in samples with little or no pyrite and high organic matter content, potentially leading to sample misclassification. High pyritic sulfur samples tend to show little difference in single-addition NAG acidities with increasing organic matter, and it appears that pyrite is preferentially oxidised by peroxide when present in significant concentrations (greater than one per cent pyritic S). In sequential NAG tests overestimation was greatest in samples with little or no pyrite, but highly carbonaceous (>20 per cent TOC) pyritic samples were affected in later stages as the pyrite was depleted. A modified NAG method is proposed to account for the relative proportions of pyrite derived acidity and organic acidity in a given NAG solution.

Jan 1, 2003

High precision GPS systems for mining are accurate to within a few centimetres. Typical systems consist of one or more GPS antenna, GPS boards, sensors to detect the position of the blade or bucket of the machine radios to pick up correction signals, a computer to control the system and a display screen to give instructions and information to the operator. GPS systems offer two benefits û they give information to the operator to get his job done faster and more accurately and they can send information to management about how the job was done. On dozers, GPS systems allow the operator to accurately complete earthmoving jobs with no survey pegs. On hydraulic excavators the systems can be used to accurately locate the position of the bucket teeth for selective mining. On blasthole drills the systems can guide the operator to each hole and record accurate as-drilled plans. By reporting the position of the blade or bucket in three dimensions it is possible to continuously upgrade a mapfile of the excavation. From this file it is then possible to report productivity numbers in real time. High precision GPS works best with a minimum of five satellites visible. This may be difficult in a pit. Systems which also access the Russian GLONASSS satellites offer significantly better uptime. GPS systems will become indispensable for efficient mining operations in the future.

Jan 1, 2003

The geological features of the destructive plate margins of the southwest Pacific favour the formation of porphyry type deposits. The major controlling factor favouring the formation of gold-rich deposits of this type is a dense crust. This results in shallow intrusion of large magma bodies beneath andesite stratovolcanoes. Where the intrusives have near vertical sides, the comparatively low temperature of transfer of volatiles from the solidifying melt favours the partitioning of gold into bubbles of volatiles. They reduce the viscosity and density of the melt, resulting in the upward movement of a mineralised melt. With the drop of pressure with upward movement the bubbles separate into a two phase mixture, triggering freezing of the mineralised melt and the formation of a gold mineralised stockwork.

Jan 1, 1995

By Stewart C. A

The Northparkes copper-gold project is being developed in Central Western New South Wales approximately 30 km NNW of the town of Parkes and approximately 350 km west of Newcastle. The project is a joint venture between North Limited (80 per cent) and the Sumitomo Group (20 per cent). North is the manager. The basis of the project is three copper-gold orebodies, the northern two of which are being mined by conventional open cut methods with the third and largest orebody at the southern end of the lease to be mined by block caving. A fourth mineralised body has been identified in the centre of the lease. While further evaluation of this deposit is required it would appear to be amenable to block caving. Oxide caps of gold ore and copper-gold ore over-lie the two northern orebodies. Development commenced with the construction of a carbon-in-pulp (CIP) plant to treat the oxide gold ore. Construction of a flotation plant to treat oxide copper-gold ore and sulphide copper-gold ore is underway. When full-scale operation is achieved late in 1996 the plant will treat 5.0 million tonnes of ore per year of which 1.1 million tonnes will be open cut ore and 3.9 million tonnes will be block cave ore. In terms of annual ore tonnage the underground mine will be the largest metalliferous mine in New South Wales and the second largest in Australia.

Jan 1, 1995

By Andrew R. L

The Kintyre uranium deposit was discovered in 1985 in the course of following up radio- metric anomalies generated in an earlier air- borne survey. The latter survey was conducted primarily to acquire aeromagnetic data for diamond exploration and the uranium discovery was made during a subsequent campaign of base- metal exploration. CRAE commitment to the Rudall area for a range of commodities over a period of 13 years made a significant contrib- ution to the discovery of Kintyre. Other con- tributing factors included CRAE's multicommod- ity approach to exploration, management support and continuity in the geological team. The Kintyre uranium deposit (Fig. 1) is located on the northern margin of the Rudall Metamorphic Complex, 60 kilometres south of Telfer and 260 kilometres north northeast of Newman, in the Paterson Province of northern Western Australia. It is 700 metres inside the northern boundary of the Rudall River National Park (15695 sq. km) and lies between the Great Sandy Desert and the Little Sandy Desert (Beard, 1969). Intense weathering since the Permian has produced a subdued landscape around the deposit. Resistant rock types still retain an older plateau surface but it is incised by more recent streams. Other Proterozoic and Permian rocks form low, sometimes rocky, areas largely covered by aeolian sand.

Jan 1, 1988

By Williams C

A stibnite concentrate from Golden Spec (WA) was subjected to a series of tests involving high pressure cyanidation and pressure oxidation followed by conventional cyanidation. The concentrate, whose gold content was 18.1 g/t, yielded only eight per cent of the gold when leached directly by a standard 24-hour cyanidation test. The recovery was increased to only 15 per cent when pressure cyanided under the following conditions: ambient temperature, 2000 kPa oxygen pressure, two hour retention time and 30 per cent w/w solids pulp density. This poor response to pressure cyanidation emphasised the refractoriness of the material. Evidence of the fine distribution of the gold through the concentrate, from measurements of the particle sizing distribution and the gold analyses of the individual fractions, also suggested that this concentrate was highly refractory. Pressure oxidation of the concentrate at elevated temperatures followed by cyanidation yielded recoveries as high as 94 per cent. However a preoxidation treatment under the following conditions was necessary: 230¦C, 2000 kPa oxygen pressure for a period of four hours.

Jan 1, 1992

By P A. Grossman, J H. Rubinstein, M Brazil, D Whittle

Many ore reserves are harvested by a combination of open pit and underground mining methods. In these cases, there is often material that could be mined by either method, and a choice has to be made. The area containing this material is referred to as the transition zone. Deciding where to finish the open pit and start the underground mine is referred to as the transition problem and it has received some attention in the literature since the 1980s.In this paper, we provide a review of existing approaches to the transition problem encompassing: graph theory-based optimisation employing an opportunity cost approach, heuristics and integer programming. We also present a novel opportunity cost approach, that takes into account a crown pillar, and show how the new approach can be best applied through the unconventional application of an existing mine optimisation tool.CITATION:Whittle, D, Brazil, M, Grossman, P A, Rubinstein, J H and Thomas, D A, 2016. Determining the open pit to underground transition – a new method, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 731–742 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By G C. Lukey, J S. J van Deventer

The disposal and subsequent encapsulation of mine tailings in a cost-effective and environmentally secure and responsible manner is one of the principal issues facing any modern mining project. A careful assessment of all options available for the capping and subsequent remediation of tailings is important because it can result in large capital, operating and closure cost-savings. For these reasons, the technology of geopolymerisation is receiving increasing attention for the stabilisation and solidification of waste materials produced from mining operations. The first part of the current study investigates the application of geopolymer technology to the capping of hypersaline mine tailings. It has been found that suitable geopolymeric materials which have satisfactory compressive strength, durability as well as low permeability, can be formed using between 60 - 75 per cent of mine tailings as the main ingredient. It has been established that geopolymeric materials have the ability to suppress dust generation and prevent salt precipitation on the surface of the mine tailings. The slurry-like consistency of geopolymers would promote efficient application procedures through established tailings disposal techniques. This is a possible close-out technique for hypersaline tailings storage facilities such as those commonly found in Western Australia, which meets both regulatory requirements and community expectations. The immobilisation of contaminant metals within geopolymers has been investigated in the second part of the present study. In particular, the leaching characteristics of Cu and Pb from geopolymeric matrices derived from different fly ash sources have been examined. Potential breakdown of each geopolymer containing metal contaminants due to the leaching of Si and Al from the geopolymeric matrix has also been investigated.

Jan 1, 2000

Compared with modern longwall coal mining systems, automation has not been developed very far in the underground metal minin industry. One of the main reasons for this is that present har rock mining systems do not produce ore with a controlled degre of fragmentation. The often poor fragmentation from the stopescauses large extra costs and precludes material which 1-ends itself to automationThe paper investigates the possibility c technology for automatic loading and trapconveyor belt to a shaft dump pocket. With this concept, it will be necessary to control the maximum fragment size by careful blasting design. The degree of fragmentation will have to be finer than is common to-day. The study shows that the belt conveyor mining con-cept with controlled fragmentation may be economically competitive with conventional cyclic loading and transport, even for an annual production as low as 0.5 mill. tonnes.. Fragmentation design and cost calculations have been based on a combination of the Kuznetsov relationship between blasting parameters and mean frag-ment size, and the Rosin-Rammler formula for fragment size distribution.

Jan 1, 1985

Subsidence prediction methods can be divided into two basic types: empirical and analytical. Empirical methods are based largely on a combination of experience, intuition and observations from a large number of observed subsidence data. They are simple in their application, but they are not based on any principle of mechanics. Analytical methods are based on equivalent material modelling principles, where the ground surrounding the extraction is mathematically represented by idealised materials that deform according to the principles of continuum mechanics. Wide applicability and improved understanding are the principal advantages claimed for this approach. In NSW, significant progress has been achieved in the area of subsidence prediction during the last ten years. Empirical prediction curves are available in NSW for predicting the ground movement in the Southern and Newcastle Coalfields. A' comparison of subsidence values predicted from these curves with the actual monitored values indicates that the curves are adequate for use in conjunction with the existing damage assessment methods. Future research for improving the existing empirical prediction curves can only be justified if it is cost effective. There are several numerical models currently in use in NSW for predicting subsidence. The models do not appear to be superior in their ability to predict subsidence when compared with the empirical curves. the performance of these models will no doubt improve along with advances in defining strata properties and failure mechanisms.

Jan 1, 1991

Exploring for deep shallow dipping orebodies can be very expensive and very difficult. Surface exploration is often not an option and obtaining the best location for underground drilling can cause production delays if drilling is carried out from development headings. The Otter/Juan mine has been in production for approximately 34 years. All of the production is now sourced from more than 1000 metres below the surface from an area known as the Edwards Lode. The orebody is shallow dipping and open at depth. Exploration drilling has been performed from decline stockpiles and from hangingwall drill drives. Drilling from footwall positions (eg decline stockpiles) into shallow dipping orebodies can often produce intersections which are unusually thick thus leading to optimistic resource figures. The decision to develop a dedicated hangingwall drilling position can vastly improve the quality of the data used to generate an orebody model. In 1997 a new extension to the Edwards Lode was discovered and named the æFÆ surface. In 1999 a resource calculation was performed using data obtained from drilling that was carried out from decline stockpiles. In 2002 a dedicated drill drive was developed into the hangingwall of the æFÆ surface to obtain better data to verify the previous resource calculation. For this case study obtaining more representative data reduced the resource estimate by 66 per cent. This information was obtained early enough to allow for alteration to the mine plan and without loss of capital.

Jan 1, 2003

By K Brown, J Webster-Brown

Coal mining activity first began on the West Coast in 1864 and has since led to the exposure of large areas of coal and host rock to chemical weathering. These exposed abandoned workings have led to the formation of acid mine drainage, which flows into selected rivers and streams impacting on the natural environment. A previous study conducted for the West Coast Regional Council identified four catchments receiving mine drainage which had elevated arsenic concentrations. The aim of this research is to expand on this initial study by determining the spatial distribution and attenuation of the arsenic within the sediment and water column in each stream of concern. Cannel Creek is influenced from drainage from the Bellevue coal mine adit and exhibits a low pH of ~3, elevated sulfate concentrations and high arsenic and iron concentrations in the sediments. This pattern is repeated in the Rapid Stream and Soldiers Creek catchments, which are also affected by adit inflows from the Sullivan and Blackball coal mines respectively. Soldiers Creek also has significantly high arsenic in the waters, with an accompanying pH of ~5.5. Snowy River exhibits a similar trait with a pH also of ~5.5, but with very low sulfate concentrations. Arsenic concentrations in the waters are consistently around 30 ppb, with sediment concentrations up to 900 ppm. These sediment values might be partially attributable to the operation of the Snowy battery gold ore production facility, but the consistently high As concentrations in the water column and in the sediment upstream of the battery have an as yet unconfirmed source.

Jan 1, 2002

The current talk of risk management as a separate discipline and management function is like earlier imposition of Quality Control (QC) as an overlay on shoddy production management. Risk management is vital, but is integral in the way we marshal our staff, make decisions, then monitor and review and make crucial secondary decisions. New leaders must not assume that hiring experts ensures good decisions. It is only the essential step one. The worst company I worked for had more expertise than the best. The difference was in culture and decision-making processes. Failed feasibility studies, persistent technical factions in a company that cancel each other, heaps of expert consultant reports piled up like a dump of bricks, even great but half-managers in large and small companies cancelling expertise at their disposal, are the worst manifestations. Just daily foul-ups are common even amongst smart people. We miners have made a great industry but are content to drift far below excellence, even where that word is bandied around. All the management literature and management courses will not right the situation û we have been sending budding managers to this good stuff for two generations and the effects are worthwhile but marginal. A few key ideals, ideas and slogans are not the way. These make inspiring books that work about as long as the Christmas spirit does in the real world. What we need is a coachesÆ manual and a standard of the essential package of culture and work processes that make excellence possible and show how to maintain it long term. It has not been written until now because most managers want to remain dilettante amateur managers without the discipline that creates excellence. First, believe excellence is possible and worth any effort; then commit to it.

Jan 1, 2007

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

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

Jan 1, 2001

By Sturgul J. R

The South Middleback Ranges (SMR) operation involves the develop- ment of iron ore resources at the Iron Duke mine in the South Middle- back Ranges to replace the Iron Baron mine whose reserves are nearing depletion. The Iron Duke mine will be developed by contract to the stage where it can continue operation at full production when Iron Baron is closed. As part of the mine planning of the operation a GPSS computer simulation model was written to determine equipment requirements. The model simulated the operation of the mine with trucks transporting ore and waste to the appropriate destinations and producing a blended product in the stockpiles. A loader and two trucks would transport ore from the stockpiles to the crusher for one shift per day. The simulation shut the operation down at crib, morning tea, shift change and weekends, and also on the third shift each day. It also modelled operating delays. The results gave equipment operating hours and total output of each material type. The model was modified to produce different outputs from the mine and could be used to determine the most productive shift arrangement.

Jan 1, 1989

During the past decade geopolymer technology has emerged as a possible solution for the effective stabilisation and solidification of waste materials. Amorphous to semi-crystalline geopolymers form by the co-polymerisation of individual alumino and silicate species, which originate from the dissolution of silicon and aluminium containing source materials at a high pH in the presence of soluble alkali metal silicates. It has been shown previously that geopolymerisation can transform a wide range of waste alumino-silicate materials such as fly ash and blast furnace slag into building and mining products with excellent chemical and physical properties, including high compressive strength as well as fire and acid resistance. These chemical and physical properties suggest that geopolymeric matrices derived from waste materials are well suited for environmental and other applications such as the encapsulation of mine tails, the immobilisation of heavy metals and also the fabrication of structural products. The current challenge is to demonstrate that a wide variety of natural Al-Si minerals could serve as potential source materials for the synthesis of geopolymers. Moreover, it should be shown on a large commercial scale that it is possible to encapsulate waste materials into the geopolymeric structure without compromising the chemical and physical properties of the final product for the desired application.

Jan 1, 2000