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By R Milton, D Hake, H Sprague

The North Western Sewer tunnel extends over 11.5 km in the North Western suburbs of Melbourne.The $253 million tunnel project provides a critical link in the Melbourne Sewer Network. The existing sewers fail to service the increasing demands of the growing population of the North West regions of Melbourne. This project will protect the environment and improve the standards of service of the existing system. This paper concentrates on Section three of this project, consisting of the final 4 km of the Contract, three access shafts and a cut and cover section of tunnel.Transfield Tunnelling as Head Contractor constructed the tunnel for Melbourne Water Corporation, with Enetech Streamline, formally Streamline Australia, a trading arm of Melbourne Water acting as Superintendent.Excavation of Section three of this project commenced in September 1994 and project completion is scheduled for October 1998. The tunnel passes below the residential suburb of Essendon, through some of the most challenging ground conditions ever attempted to be tunnelled in Australia.

Jan 1, 1999

Minerals similar to the indicator minerals used in kimberlite exploration are widespread in the Cainozoic alkali basalts of north Queensland. Magnesian ilmenite, pyrope garnet, chrome diopside, chrome spinel, phlogopite and zircon were recovered from most of the localities examined. The occurrence of these minerals creates significant problems when indicator minerals are used for diamond exploration. Basaltic ilmenite is visually similar to kimberlitic ilmenite. Untransported grains are rounded and have pitted surfaces. Basaltic ilmenite grains often have exsolution lamellae and reaction rims of titanomagnetite. Although kimberlitic and basaltic ilmenite are chemically similar, basaltic ilmenite grains are usually less magnesian than their kimberlitic counterparts. Basaltic ilmenite contains very little Cr203. Pyrope garnet occurs as megacrysts and in a variety of xenolith lithologies in north Queensland basalts. Most basaltic garnet is Cr-poor and comparable with kimberlitic garnet from Groups 3 and 5 of Dawson and Stephens (1975). Wine-purple, chrome-bearing garnet is common in kimberlite but rare in basalt.

Jan 1, 1984

By De Broglio R

The Mae Moh coal deposit was discovered some 60 years ago by villagers who noticed spontaneous combustion of coal outcrops. The first production began in the 1950's to fuel a fertilizer plant and a 12.5MW power station. During the period 1976 to 1979, three 75MW power station units were constructed on site. These have a total daily coal consumption of some 5000 tonnes and are served by a stockyard of approximately 60 000 tonnes total capacity. Stacked coal is reclaimed by means of a front end loader onto reclaim conveyors. During the years 1983 to 1986 four 150MW power station units were constructed east of the eastern seam subcrop, sons 2 km from the original power station complex. These have a daily coal consumption of nearly 12000 tonnes and are served by a stockyard of total capacity 270000 tonnes, equipped with two stackers and two bucket-wheel reclaimers for a totally mechanised system.

Jan 1, 1986

By P Wollants, B Blanpain, R Ding

Vacuum oxygen decarburisation (VOD) is the refining process used by ALZ (Genk, Belgium) for their production of stainless steels. The process consists of three stages: oxygen blowing at a pressure of 100 mbar, degassing, and reduction of the slag with ferrosilicon at 5 mbar. The magnesia-chromite bricks used in the slag zone of the ladles suffer from acute wear. In this paper results obtained from a program to improve the refractory life span are presented. The dominant wear phenomena were identified with an electron microscopy study of bricks taken from different locations in the ladle. Concurrently a dynamic model for the vacuum oxygen decarburisation (VOD) refining process was developed. The model calculates the elementsÆ oxidation rate during the blowing oxygen stage and allows the continuous calculation of the change of the metal, slag and gas composition throughout the VOD process. From these activities a general scheme of the refractory wear was worked out and measures to improve the refractory life were proposed and implemented.

Jan 1, 2000

By Trevits MA

The United States Steel Corp. in cooperation with the United States Government is conducting a large-scale methane drainage field demonstration using stimulated vertical boreholes drilled in advance of mining. A grid pattern of 23 boreholes, isolating approximately 1.5 km2 of coalbed area, has been drilled to the lower bench of the Mary Lee coalbed, Jefferson County, Alabama. Upon completion of drilling operations, various hydraulic stimulation treatments utilizing nitrogen-generated foam, water, and gelled fluid were performed to enhance the rate of methane gas removal. Production from the grid pattern began in September 1977 and continued as the last borehole was placed on production during October 1980. To date, in excess of 33,800,000 m3 of methane gas has been drained as a result of this effort. Underground mining operations were approximately 3.2 km from the grid pattern when production began and have currently progressed to within 1.6 km. Underground interception of the grid is expected in 1986.

Jan 1, 1982

By P Campi, M Dodds

The EastLink project is a 39 km tollway to the east of Melbourne and includes twin three-lane 1.5 km driven tunnels. The hard rock tunnels are being built to avoid passing the motorway through the Mullum Mullum Valley to help preserve the unique flora and fauna in the area. This paper describes the process of transferring the support requirements from the ædrawing boardÆ to the tunnelling face by integrating the temporary support design with the contractorÆs tunnel excavation and support procedures, including sharing of responsibility between the designer and contractor for selection of the support type and the production of a project specific rock mass classification system to enable more objective determination of ground conditions. The methods developed during the design phase incorporated a formal system of reviews, support selection and feedback by monitoring tunnel and ground responses. During construction, the process was implemented using a set of simple documentation and regular structured communication between the contractor and the designer.  

Jan 1, 2008

By H Han, X Wang, T Li, D Duan

"In this paper, the reduction and separation behaviour of iron and slag in carbon composite iron ore pellets has been investigated experimentally using an electric resistance furnace simulating a rotary hearth furnace process. The factors that affect the formation of iron nuggets, such as temperature, holding time, molecular ratio of C/O and basicity, are discussed. Results show that the reduction of iron ore, carburisation of reduced iron and the composition and quantity of slag are very important for producing iron nuggets. Through optimisation of process parameters, iron nuggets can be formed below 1300¦C when holding time is 20 minutes, C/O is 0.7 and basicity less than 0.5. This study provides a theoretical and technical basis for iron nugget production.CITATION:Duan, D, Han, H, Wang, X and Li, T, 2013. Iron nugget production technology in rotary hearth furnace process at lower temperature, in Proceedings Iron Ore 2013, pp 363-368 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

During the century past geologists have discovered an extraordinary range of mineral resources. It is somewhat surprising, in view of their success, to look back and find that geologists have been concerned through the entire time about the adequacy of resources to meet future needs. They continue to express concern. The basis of their concerns seems to rest as much in social issue as in evaluations of geology.Demand for mineral resources is driven by population and by per capita consumption. Both have grown steadily over the past century, and both continue to rise. In 1890 the global population was about 1.7 billion, people. It has now exceeded 5 billion and the growth rate is such that by the year 2000, the global population will be between 6~ and 7 billion. Demographic projections suggest the global population will approach 12 billion before a steady state is reached dnrino the centiirv ahead

Jan 1, 1990

The Century zinc-lead orebody was discovered in 1990 and contains sufficient reserves to sustain open cut mining at 5 Mtpa of ore for approximately 20 years. It is proposed to pipe mineral concentrate in slurry form 300 km from the mine to the port of Karumba on the Gulf of Carpentaria. The concentrate will be dewatered at Karumba before being transported off-shore to deeper water in a self-unloading shuttle vessel for transfer to export bulk carriers. The four main environmental issues that attracted attention during the impact assessment phase of the project were: the selection of Karumba as the export port, the use of a pipeline to transport concentrate, the risk of concentrate spillage in the marine environment, and aquifer drawdown in the vicinity of the mine. This paper discusses these issues with emphasis on the context of the relationship between the Pasminco Century Project and Gulf communities. Environmental safeguards are discussed, including those that arose out of the negotiations regarding Aboriginal native title.

Jan 1, 1998

By G Lane, S Morrell

The design of the 12 m diameter SAG mill installed at the Cadia Hill Mine in New South Wales followed after two years of extensive laboratory and pilot plant testwork. The testwork showed the Cadia ores to be hard and competent necessitating the use of both a variable speed SAG mill drive and pebble crushing. The grinding power requirements for the SAG mill was based on engineering in-house grinding software, pilot plant data and simulations using JK SimMet software. Surveys of the SAG mill operation during the first four weeks showed the feed size distribution, transfer size and pebble rate to be lower or less than those for which it was designed. To compensate for the lower pebble rate, the SAG ball load was increased. This resulted in the total comminution circuit power being some 0.5 kWh/t higher than predicted. The JK SimMet SAG model has been modified to take account of these variations.

Jan 1, 2000

By Lee G, Stitt P

The term "industrial minerals" covers a vary wide field. However in Australia this field tends to be characterised by the follow- ing: (1) Relatively low unit values. (2) Product specifications can be exacting compared to the metalliferous field. (3) Product specifications often have to be tailored to the needs of the end user. (4) Beneficiation plants tend to involve low capital outlays relative to the metalliferous field. However they often have to produce products'to a range of specifications. (5) Technology often influences what can be considered as reserves. (6) Because of low unit values industrial minerals tend to be relatively cost sensitive. This is particularly the case in regard to transport. (7) Location of deposits near to major urban areas (markets) dictates a greater pressure on ecological aspects. (8) In Australia there has been a tendency to vertical integration largely due to the restricted market available. Reserves assessment is shown to be critically dependent upon the above Factors.

Jan 1, 1979

During the 1960s chalcocite ore was mined from the Black Rock open cut. A large amount of this uneconomic material was not treated by the No 3 Concentrator at the time and as a consequence a surface stockpile was created which contained 750 000 tonnes of material at an average of 1.5 per cent copper.Laboratory trials indicated that due to oxidation, an average of 25 per cent of the copper was water soluble and the remaining copper was leachable using a sulphate/ferriclbacterial leach. On the basis of these trials it was decided to investigate the feasibility of producing copper via a leach SX-EW process. The investigation proved the process was feasible, so began the design, construction and commissioning of a 10 tpd (cathode copper) Copper Leach SX-EW Pilot Plant. CMPS Pty Limited in a joint venture with John Holland Engineering Pty Limited were awarded the turnkey contract for the design, construction and commissioning of the Pilot Plant.

Jan 1, 1993

By Lawrence PR, Hoffman W

The dissolution of gold from various ore-bodies is discussed in terms of extraction rates and reagent consumptions during leaching. Gold dissolves slowly in cyanide but reagent consumptions are usually satisfactory. In almost all cases where excessive cyanide consumptions occur, similar high consumptions result with other lixiviants. Recovery of gold from cyanide solution is well established and comparatively simple technology.Gold dissolution in thiourea is faster than cyanide but significant consumptions of thiourea, due to both adsorption and oxidation, occur. Gold recovery from thiourea solutions is likely to be more difficult than from cyanide.Chlorination of gold is very fast in acidic conditions but excessive consumption of chlorine occurs for ores containing greater than 0.5% S. Reprecipitation of gold and handling of acidic chlorine solutions are both significant problems. The mechanism of gold reduction onto activated carbon creates difficulties in the carbon in pulp process for recovery of gold but means a simplification in the production of bullion from loaded carbon.

Jan 1, 1984

The blasting of the 2190_6095 stope at Kimberley Nickel MineÆs Sally Malay operation in Western Australia is an example of what can be achieved with electronic detonating systems when a drill and blast engineering team is faced with complex blast geometry and a major pump station in close proximity to the stope. Using Dyno NobelÆs HotShotÖ system, the engineering team successfully designed and initiated the 36.5 Kt stope firing, with a powder factor of 0.35, resulting in no damage to the pump infrastructure, better fragmentation of the ore and less overbreak in what had previously been a geotechnical and geometrically challenging stoping environment. This paper will discuss the design parameters used for this stope blast as well as the benefits the operation found in using precision detonator timing in this 252 hole shot over two levels using a combination of up and down and slashing rings that were initiated in four different directions.

Jan 1, 2007

The Mining Act (1992) and the Petroleum Act (1980) provide for the Government of Papua New Guinea (PNG) to take up equity holdings in mining and petroleum projects. The price the Government pays for its share is based on the historical cost of exploration and development on the project to the date of government equity acquisition. The equity level to be acquired is not fixed and ranges up to 30o for mining and up to 22.5s for petroleum at the discretion of the Government of the time.The objective of this paper is to examine the pros and cons of State equity holdings in PNG from the point of view of both the State and the developer. Using an economic model of the PNG mining taxation system an assessment is made of the effective return on investment received by the State from such equity holdings. The results are compared with government revenues from other taxation measures.

Jan 1, 1994

The celebrations which took place in 1986 to mark South Australia's Jubilee 150 served to focus attention on all aspects of the State's heritage. Until that time the sites and relics of South Aus- tralia's early mines had been generally neglected. Marked by the ruins of enginehouses and littered with the remains of the massive technology of the Industrial Revolution, these sites have now been recognised as containing the threads of a fascinat- ing story. In the early days of settlement the economy of the Colony was based on land and farming. Droughts caused periods of economic depression which were alleviated by chance discoveries of gold, lead, silver, and copper ore. Some of the mines which were opened on the copper deposits were the largest in the world at that time and their names well-known throughout mining circles. Working by hand with primitive equipment, the early miners excavated vast networks of shafts and stopes often extending to great depths: at Moonta- Wallaroo Mines for example workings extended to 860 m below ground. Because of the presence of underground water, mining to these depths would not have been possible without the Cornish pumping engine. Operated by steam power these massive engines and their associated equipment were transported from Cornwall by clipper and delivered to the mines by bullock cart. At this time the engines were at the peak of their devel- opment and, although expensive to import and install, they were highly reliable: the engine oper- ating Hughes pump at Moonta worked continu- ously for sixty years without a major breakdown.

Jan 1, 1987

By C Young

The identification of Critical Risks, their associated Critical Controls, and the implementation of processes to ensure their ongoing management can be difficult and resource intensive. Answering the following Critical Risk Management related questions can be challenging: • What is a Critical Risk? • What is a Bow-tie Analysis and when should it be used? • What is Critical Control? • How is the effectiveness of a Critical Control assured, and how is this measured? • Who is responsible for managing Critical Controls? • What are the implications if a Critical Control is not effective? It appears that in the mining industry’s efforts to implement the Critical Control Management Process outlined by the International Council on Mining and Metals (ICMM), instead of embedding an integrated, well understood, value adding process, we have instead created a resource hungry monster that is poorly understood by numerous layers of the organisation.

May 5, 2022

Process mineralogy is an inter-discipline in the fields of mineralogy and mineral processing. As a predicting and trouble-shooting tool, process mineralogy helps address all mineralogical issues and problems related to mineral processing. It provides useful information on process design and optimisation, flow sheet development and cost reduction. As more and more complex and refractory ores are being discovered and processed, it is believed that process mineralogy will gain more attention and play a more important role in process design and optimisation. This paper will first discuss the scope of process mineralogy and mineralogical factors that may affect mineral processing of various ores, and then focuses on the application of process mineralogy in process design and optimisation through case studies.

Jan 1, 2008

By B Walsh, M Cattani, S Verpaele

With the increasing sophistication of real-time sampling devices for occupational hygiene exposure assessment, research to objectively assess their performance is a priority. Using real-time monitoring equipment has several advantages over established gravimetric sampling methods, particularly their immediate results, lower overall long-term costs and no laboratory analysis costs, which are appealing to the mining industry due to the ongoing occupational hygiene monitoring programs required by the various regulatory agencies.

Apr 16, 2024

By K Zhao, H Gong, B Li

Health and safety are the first priority for Australian minerals sector. Australia has a global reputation in the mining industry. However, accidents occur every year. Legislation and regulation are important to prevent the accident from occurring, so do the new technologies. It is sad to witness the collision incident persisting and the long called collision avoidance system (CAS) is still not widely used in underground mines. The main reason is that the existing systems are still not advanced enough. The current CASs utilise GPS, infrared, ultrasonic, RFID, Radar, electromagnetic etc have their limitations and disadvantages. For instance, GPS is widely used in a surface mine, but it cannot be applied in underground mine; Infrared and electromagnetic have the false positive problem.

Sep 1, 2024