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A typical large surface mine in Scandinavia has hard rock, a cold cli- mate, poor ore, a complicated vein type orebody and high labour costs. In order to survive, these mines have to maximise their ore production, minimise waste extraction and get the most out of every man hour. This article describes two examples of how inclined blastholes drilled with hydraulic percussive drills can help to meet these requirements. Both of these Scandinavian mines, Kemira Ltd's Siilinjarvi mine in Finland and Sydvaranger A/S's Bjornevattn iron mine in Norway, use inclined blastholes of 200 mm in diameter. The Siilinjarvi quarry is using inclined holes in production drilling. The Bjornevattn iron mine is blasting the final pit walls with inclined holes. The benefits gained when using inclined instead of vertical blastholes are better selectivity, better bench drilling conditions, steeper final pit walls and increased safety.

Jan 1, 1989

By Bourke J. H, Ashcroft T. B

Many changes have occurred in the world market for manganese over the last five years. Among these, the emergence of divided steel processes for the hot metal refining of pig iron is affecting the use of both ferruginous manganese ore and ferro manganese, at this stage particularly in the Japanese steel industry. Subsequent demand for higher quality manganese materials is promoting the use of thermally beneficiated products such as sinter. In addition, many processes are being developed for the direct smelting of fine manganese ores, of which plasma technology is the most advanced. Cost pressures and product quality requirements are encouraging pre- viously self sufficient countries such as The People's Republic of China and the USSR to import high grade manganese ores to supplement indigenous lower quality supplies. At the same time, Brazil has been provided with the impetus to convert its substantial reserves of ore to value added products.

Jan 1, 1988

A Devonian metallogenic province is extended northwards from central Queen- -sland to the Burdekin Basin in the Charters Towers Gold and Mineral Field. Devonian sediments of the Burdekin Basin are intruded by mineralised quartz felspar porphyry which occurs as pebbles in Upper Devonian conglomerate. A mineralised volcanic complex lies on the crest of an anticline in Devonian sediments.Red siltstone is slurried and reduced to pyritic hornfels over folded limestone.A thick wedge of volcanogenic conglomerate overlain by marine shale lies on the mineralised rim of an ocean which suffered cataclysmic changes during Late Devonian times.

Jan 1, 1987

By Milner E. F

Thallium is largely volatilized during sintering in the conventional sinter/blast furnace production of lead. The new direct oxygen smelting processes will force the thallium into the bullion, necessitating a means of removal to avoid contamination of the refined lead. Pilot plant testwork demonstrated that thallium was efficiently removed from lead bullion by treatment with molten zinc chloride. The spent zinc chloride salt was treated in the laboratory to recover lead sulphate, a zinc chloride solution, and a thallous chloride salt containing over 80% thallium. Cominco is installing this thallium process as part of its Trail Lead Smelter Modernization Program which will commission a QSL bath smelter in late 1989.

Jan 1, 1989

The, Ore-bodies.-The ore-bodies of the North mine, North Broken Hill Ltd.; consist of two lenses, connected by a narrow neck of mineralized country. They pitch at an angle of 40° in an easterly direction and dip north at 60° to the horizontal. The southern ore-body, on a horizontal plane, has a total maximum length of 800 feet and in one place attains a width of 230 feet, whilst the northern orebody has a maximum'length of 600 feet and a maximum width of 80 feet.

Jan 1, 1940

By Phillips H. R

The action of free rolling disc cutters is well understood, relationships between disc geometry and performance having been established both in the laboratory and under field conditions. However, under severe operational conditions a malfunction of the disc bearing assembly is likely to produce a definite change of cutting action. Collapsed or siezed bearings can even prevent the disc from rolling and thereby create what is equivalent to a drag pick. This paper describes a programme of laboratory experiments using deliberately stalled discs. Their performance under such conditions is contrasted with that for a free rolling disc and also with a drag pick having a ridged front developing into a negative radiused back clearance angle. In conclusion an assessment is made of the influence stalled discs can have on the torque and thrust requirements for a tunnel boring machine.

Jan 1, 1981

By Wiltshire PG

The process uses sodium hydroxide and sodium nitrate reagents as in conventional Harris refining plants, selectively removing the arsenic to the caustic phase at an operating temperature of 420-450¦C. A novel feature of the process concept is continuous treatment of loaded caustic slag for recovery of arsenic as a sandy crystal product suitable for further processing to arsenic trioxide. A large pilot plant was constructed and operated over a period of 3 years to develop materials handling techniques and equipment components and to prove the concept. Stable operations were achieved at equivalent capacities of 200 tonne/yr arsenic removal. The process is being considered in plans for expansion of bullion softening capacity at Port Pirie.

Jan 1, 1984

By Lean P. J

The present The Zinc ODrporation, Limited and New Broken Hill Consolidated Limited (ZC/NBHC) tailing dam (Site C) is expected to reach its terminal capacity late in 1985. Planning and design of new facilities for disposal of tailing after 1985 which includes new tailing dams (Site D) commenced during 1980. This paper briefly describes planning guidelines and specifications, location considerations, environmental aspects, operating strategy, engineering specifications, envirormental aspects and scheduling of works.

Jan 1, 1983

The source and origins of the hydrothermal fluid of orogenic, or quartz-vein lode-gold deposits remain uncertain and disputed: Resolution would likely have a significant affect on exploration strategy. The gold-carrying fluid is interpreted to be a low-salinity mixed aqueous-carbonic fluid of near ambient pH and redox state, that may be derived either magmatically through crystallisation of granites at depth in the crust or through metamorphic reactions in a range of rock types. Classic isotope and geochemical tracers of fluid source have not differentiated these possibilities and have produced conflicting conclusions. Mass balance calculations show that fluid composition will be modified by wallrock reaction between source and deposit, and tracers should not be expected to give clear indications of fluid source. Fluid oxidation state can also be modified along flow paths. Tracers should be interpreted with care and with view to possible modification. Modelling of full flow paths and examination of the hydrothermal histories of proposed source rocks may be alternative approaches to determining fluid source.

Jan 1, 2002

The facilities used and techniques employed in the manufacture of steel and iron rolls at the Steel Foundry, B.H.P., Iron & Steel Works, Newcastle are described.

Jan 1, 1972

This paper outlines the manner in which legislative control for tunnelling and allied operations has evolved, detailing Victorian experience. It examines the concept of mine managers as it relates to the industry and attemps to illustrate its benefits. The Victorian experience in relation to fatal and serious accidents is examined in detail, particularly in the allied art of trenching and examines the Krings system of trench lining support which is hoped will catalyse an increase of engineering expertise in this area. The paper concludes by demonstrating that safety awareness is not incompatible with production efficiency or economic viability.

Jan 1, 1981

By Ross T. J

Renison Limited operates an underground tin mine employing both cut and fill and open stope methods, at Renison Bell on the west coast of Tasmania. Mining in the region commenced in the 1890's. Development of the current mining operation commenced in 1965. The ventilation system used at Renison in its present configuration is a function of current mining methods, orebody characteristics and prevailing Tasmanian Department of Mines Inspection Regulations.

Jan 1, 1988

In 1976, The Zinc Corporation Limited Broken Hill set up a plant to re-process a hill of tailing (Mt. Keast) from the original treatment operations. With the likely disappearance of this source of feed in 1985, an investigation was initiated to determine what other feed sources might be available. This involved searching through old records and photographs as well as a subsequent drilling campaign. The paper briefly covers the history of treatment operations and describes, as a result of the information obtained, the likely future sources of feed.

Jan 1, 1983

The Vera Nancy orebodies, although simple in overall geometry, are in detail generally narrow, multi-veined and fluctuating in width, strike and dip. Tight geological control is required to optimise gold and silver production from this bench stoping operation. The processes used to model the resource and to control ore drive development have evolved since mining commenced in 1997. Grade control is a combination of orebody sampling, geological data collection, understanding orebody geometry and the optimisation of ore driving and stoping activities. Global resource modelling utilises mainly drill hole data which is largely superceded by drive development data as stope development progresses. The orebody has a relatively low nugget effect that assists in grade estimation. Rather than rely on sophisticated grade interpolation methods, resource estimation to-date has focussed on developing the geological understanding of the orebody to ensure the framework for estimation is correct. Drill data alone is not adequate to define deposit geometry for stoping . Drive data is used as the dominant data set for stope geology modelling once development for a stope is complete.

Jan 1, 2000

Severe development difficulties were experienced soon after in-seam mining commenced at Appin Colliery in'1962. Thirteen years later no significant pro- gress had been made in overcoming some aspects of this development problem. Some success had been achieved in destressing roadways both in development and pillar extraction. Longwall retreat mining had shown promise of being highly productive but at an extremely high cost in terms of development requirements both in number of roadways and intensity of support in those roadways. No real advance was made in the problem of driving the first heading of a group of headings under conditions of apparently high stress in directions other than the preferred mining directions, although failure of the roof in this heading did seem to give easier work in the subsequent headings driven particularly if they were driven on narrow centres.

Jan 1, 1976

By Smit J. G

Following an increase in the number of methane ignitions in South African coal mines a new ventilation system was developed. The "Hydravert" system conceived in late 1979 for use in low seam coal mines, where the bord and pillar method of working is used, has been extensively developed to include applications for mining seams up to 4.5 metres high. A brief history of the development is supplied including some of the pitfalls encountered in the hydraulic equipment design and selection.

Jan 1, 1988

By T Ueda an, T Sasaoka, A Yabuki, H Shimada

The basic concept of auger mining is to extract coal beyond the economic limits of surface mining technology by drilling holes of an appropriate diameter size into the exposed seam of the highwall as deep as is technically, economically and operationally feasible. This method of mining is used at the final highwall of typical surface mining operations. This paper describes the auger mining systems and discusses the methods to increase the coal recovery in auger mining from a field trial in Australia.

Jan 1, 2003

By S Holmes

Solid Energy New Zealand operates the Stockton Opencast Coal Mine, a unique deposit consisting of high quality hard coking and thermal coals. Stockton's uniqueness includes high variability of the shipment specifications, strict quality constraints, minimal stockpiling capacity in the coal transport chain and the variability of coal quality both vertically within the seam and laterally across the deposit. The process of resource proving and modelling results in a high level of understanding of the deposit to allow detailed planning to be undertaken. The use of computer aided mine planning tools is an important component of the mine planning at Stockton. Detailed planning is implemented in the field through selective mining practices and monitoring to minimise dilution and maximise recovery of the coal resource. The quality variability in the coal, the æjust in timeÆ approach of the coal transport chain and markedly varying quality specifications from shipment to shipment requires a large coal inventory and the mine to be driven by quality constraints rather than material movement capacities.

Jan 1, 2003

By Li T

Mining of the southern 1900 copper Orebody presented a challenge due to the complex geology, geometry and simultaneous extraction of the nearby lead/zinc/silver orebody. An integrated and co-operative approach was adopted, involving geology, geomechanics, mine planning and production personnel. Successful extraction of the first 1900 Orebody stope, T496, together with the extraction of the first two lead/zinc/silver panel stopes in the immediate hangingwall of the 1900 Orebody stope was achieved as a result of this approach.

Jan 1, 1995

By Gunn S. G, Wilson E. G

Studies by Telecom showed that the existing cable tunnel system in the Melbourne C.B.D. required expansion in order to meet the future telecommunications needs of the City. Due to physical locations of the various telephone exchanges in the CBD, together with a necessity to connect into existing ATC tunnels, a network of low cover small sized tunnels was proposed to maintain and extend the existing telephone cable network. This paper reviews the feasibility studies, design criteria and constructional aspects involved in building 5 tunnels (total length of 1850 m) and 13 chambers (4 open cut and 9 underground)-together with ancillary works, which form part of the new cable tunnel network.

Jan 1, 1981