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This paper discusses how the i-kon TM Digital Energy Control System may be deployed by miners of massive underground orebodies to deliver significant advantage in terms of safety, cost and environmental compliance. Digital Energy Control offers an exciting opportunity for mine operators to review their blasting and mining practice to gain the most advantage from this new technology.

Jan 1, 2000

Lake Kopiago is located some 71km northwest of Tari in the Southern Highlands Province and lies on the northern edge of the Papuan Fold Belt. The area is underlain by middle Miocene carbonate and fine grained clastic sediments intruded by late Miocene hornblende gabbros.Two mineral deposits occur to the south of Lake Kopiago. These are the Bisamu gold prospect and the Wunaki zinc-lead gossan.The Bisamu deposit consists of a calcic skarn assemblage which is geochemically anomalous in gold, silver, copper, zinc, cobalt, bismuth and tellurium. The prograde mineral assemblage includes garnet, clino-pyroxene and epidote whereas the retrograde assemblage includes epidote, quartz, actinolite and chlorite. Pyrrhotite is the dominant sulphide with minor pyrite and marcasite and trace chalcopyrite and sphalerite. Minor magnetite is also present. The Bisamu skarn shows many of the features typical of gold-skarn type mineral-isation.

Jan 1, 1994

The Lake Rotokaua sulphur deposit, near Taupo, New Zealand, is a lacustrine sedimentary ore body, 220 acres in area and from 7 ft to 96 ft thick, containing, within the area drilled to date, some 20 million long tons of ore averaging 25% elemental sulphur in unconsolidated tuffaceous diatomaceous clay, overlain by about 120 ft of pumice sand and by the shallow Lake Rotokaua. An additional amount of perhaps 4 million tons of sulphur is regarded as probable in the area remaining to be drilled. Current economic studies cover the problems of mining an unconsolidated water-saturated formation with some residual thermal activity nearby; conservation and restoration after mining in a scenic recreation area; beneficiation of the ore and extraction of high- purity sulphur, principally for fertilizer manufacture. The deposit has additional importance as a pointer to possible further discoveries in the Thermal Region.\

Jan 1, 1971

By Quemard D, Troncoso J

The Gordonstone Project with a capital cost in excess of $500 million will become the largest underground coal mine in Australia. The project development decision was taken on 31 July, 1990 and at 31 May, 1991 construction was approximately 35 per cent complete. The first train of processed product coal will be railed to Gladstone during December 1992. The general theme of this paper therefore will address the planning and development processes at Gordonstone particularly the interrelatedness of technical, production, construction and environmental disciplines to ensure success during operations.

Jan 1, 1991

Standard petrographic profiles for many Permian seams from New South Wales and Queensland have been drawn up. The standard profiles of seams of the same age and from one or more coalfields were used to compile an idealized or type seam sequence for those coals in which more than half the seam profiles were similar to one another. A marked similarity existed between at least 7 of the 10 type seam sequences formed. The configurations of the vitrite-plus-clarite contents of the plies of 95 per cent of the seams could be formed from different arrangements of 3 basic sequences: (i) a two-ply sequence with a lower vitrite-rich and an upper vitrite-poor ply; (ii) a two-ply sequence with a lower vitrite-poor and an upper vitrite-rich ply; and (iii) a four-ply sequence of 3 plies with vitrite-plus- clarite decreasing upwards, terminating in a vitrite- rich ply. The third basic sequence was very similar to a succession described for some British Carboniferous coals. Eighty per cent of the Australian Permian coal seams studied began with the first (i) basic type of sequence and are interpreted as originating in peat- forming areas which became progressively drier. More than half the seams were formed in an area with a stable depositional surface level which was subject to oscillations of small amplitude.. Many (30%) were formed in an area with a steadily rising depositional surface level.

Jan 1, 1969

By Sullivan BJK

The 1100 orebody is a massive copper sul- phide orebody which contains a major portion of the Isa Mine copper ore reserves of 130 million tonnes at 3.2%. The underground mining of a deposit as large as the 1100 orebody is technologically a complex operation as extraction strategies have to be evaluated with reference to 1. rock mechanics considerations, 2. safety and environmental standards, 3. production and operating require- ments and 4. metal recovery and costs. The mining philosophy in the orebody has undergone considerable change over the past five years as a result of experience and improved technology. At this stage, primary stopes are extracted by high rise sublevel open stoping and pillars by slot and mass blast drawn either under rock fill or as an open Stope.

Jan 1, 1978

The Carnilya Hill Mine, a joint venture project between Western Mining Corporation Limited (WMC) and The Broken Hill Proprietary Company (BHP), is a nickel sulphide deposit being developed by the Kambalda Nickel Operations (KNO) of Western Mining Corporation. Seven months elapsed from the time a decision to proceed with the project was taken until the first ore production. During the first month of operation a new KNO record for decline development was set. Equipment used includes an electro- hydraulic drill jumbo, 4 cubic metre front end loaders, and 35 tonne haulage trucks.

Jan 1, 1981

By Nguyen G. H, Graham J

A laboratory-scale fluidised-bed roaster has been used to examine the effect of temperature and duration of roast on the morphology of the calcine produced from a pyritic gold-bearing concentrate. Two mechanisms of oxidation, which depend on the roasting temperature, have been identified. For samples roasted below 550°C, direct oxidation of the sulphide occurred to form hematite with a porous fine-grained concentrically-layered texture. The surface area of the calcine increased with an increase in roasting temperature in the range 400 to 500°C. For samples roasted above 550°C, the first reaction was the evolution of sulphur vapour to produce pyrrhotite, which underwent increasing grain growth as the roasting temperature was increased. This had the effect of decreasing the surface area of the calcine. The pyrrhotite was subsequently oxidised to produce hematite.Leaching studies using cyanide solution indicated that gold extraction around 95 per cent was achieved at temperatures of 500°C and above, with optimum extraction, taking into account rate and cyanide consumption in the range 550 - 700°C. Hence recovery did not decrease with decrease in surface area of the calcine. Observed gold in leached calcines was mainly enclosed in thin oxide walls of the hematite, with minor quantities enclosed in quartz and silicate minerals.

Jan 1, 1995

The iron ore mining operations carried out by Goldsworthy Mining Limited at Golds- worthy, Shay Gap and Sunrise Hill, in the Pilbara region of the North-West of Western Australia, are unusual insofar as the ore reserves occur in a number of widely separated and relatively small deposits, requiring deep mining below the water table, and even below sea level at the Goldsworthy pit. This paper has been prepared to describe some of the problems associated with these deep open cut mines, and the technology employed to overcome them, in order to provide an efficient and economical operation. The problems discussed are: 1. Development of the Dewatering System for the Goldsworthy Mine. 2. The Stability of Pit Slopes at the Goldsworthy and Shay Gap Mines. 3. Development of Diesel Electric Trucks for Lonq Uphill Hauls.

Jan 1, 1979

By Woodcock J. T, Rummel P. H, Sparrow G. J, MacRae C. M

An automated method, which is believed to be the fastest in the world and which can be used by mineralogically-untrained technical assistants, has been developed for the rapid location of native gold particles and other gold minerals down to 1 pm in size in ores, concentrates, and tailings using a scanning electron microscope. Searching of a 25 mm diameter polished block in 1 pm steps usually requires 3-4 h. Examples of the location of native gold and gold tellurides in drill core sections, in crushed ore samples and gravity and flotation concentrates, and in various metallurgical test products are given. The results have application in ore exploration, in guiding metallurgical test programmes, and in assessing metallurgical per- formance in testwork and in operating plants.

Jan 1, 1991

By Klenowski

Rational design of layouts for longwall operations is greatly facilitated by use of an accurate and economical method for predicting stresses and displacements. The displacement discontinuity method (a form of boundary element method) is based on replacing actual excavation geometries by thin slits of the same plan area. This approach allows three-dimensional stress- analysis at a fraction of the cost of alternative methods. The analyses can be readily performed on economical microcomputers, putting the analysis capability within the reach of mine-site personnel. This paper describes investigations associated with the German Creek Central Colliery, the first longwall operation in Queensland's Bowen Basin. The material properties used in the model, in particular the rock mass and goaf properties, have been 'tuned' to fit stress measurements obtained during extraction of the first and second longwall panels at the mine. The study shows that model predictions based on suitably scaled anisotropic rock strata properties are in good agreement with the stress measurements made to date. This model predicts average chain pillar loads significantly higher than predicted by models based on United Kingdom conditions. A working chain pillar design method is proposed using average pillar loads predicted by the numerical model and ultimate strength characteristics given by Bieniawski's formula.

Jan 1, 1988

Methane predrainage from coal seams in the Western Area of the U.K. has been practiced over the past decade. The differing reasons for the practice include the controlling of gas emission rates in coal headings required to win out coal faces and also the need to control the gas emission rates in the roadways of retreat faces in order to comply with the statutory requirements. There are some similarities with predrainage experience in the Bulli Seam NSW. The several case studies highlight the varying conditions in the Western Area coalfield where the use of predrainage was Required.

Jan 1, 1982

By Kukla G. T

A Seam deposit User oriented Mine Planning System (SUMPS) was developed by The Broken Hill Proprietary Company Limited (BHP) at its head office in Melbourne. It is one of the computer mine planning systems developed by the Corporate Data Processing (CDP) section of BHP. To date it has been employed in the feasibility study of four coal prospects for the BHP Group, including Gregory in central Queensland - Ham and Van Hoorn (1978). It was also used in detailed short term mine planning for Gregory. A recent application was in the feasibility study of Saxonvale, a multi seam coal deposit in New South Wales with seams up to 20 m thick. The other two applications of SUMPS were also on thick multi seam coal deposits. Development of programs for the underground sub-section of SUMPS is continuing. SUMPS was developed and implemented on mini computers with graphics and plotting peripherals. The company's philosophy towards computing is one of centralized development and project planning, with transfer of hardware and software to site once the mine becomes Operational.

Jan 1, 1980

The Porphyry Gold Mine (150km NE of Kalgoorlie) was reopened in November 1983 with production commencing in April 1984. Original reserves quoted for the open pit were 822000 tonnes at 5.2 g/t Au based on wide spaced diamond drill holes. Close spaced grade control drilling has revealed some loss of tonnage and a significantly lower grade. In the area of the pit mined to 30 June 1985 this grade control reserve estimate contained 67% of the gold in the original ore reserve with the grade being 19% lower. It is anticipated that the final grade control reserve estimate will contain around 80-85% of the gold contained in the original reserve. There has been close agreement between the Mill Head grade (4.19 g/t Au) and the grade control predicted grade (4.2 g/t Au) confirming that dilution is not a major problem. After initial poor agreement (attributed to "lock-up" in the circuit) the bullion calculated head grade steadied out at 93% of the grade control prediction. This difference is considered to represent the geostatistical bias in the drill hole/crushed rock sampling. Gold recovery has been in the range 93-95% (compared with bullion calculated grade). The net result is that the recovered grade of ore mined to 30 June 1985 is 70% of the original ore reserve grade.

Jan 1, 1986

By C Gypton

This paper gives some insights into what to look for when reviewing feasibility studies. The review by a third party is an important element of the risk management process and may be the last remaining opportunity to uncover errors, or identify and reduce project risks on paper before they are converted to financial disappointments, steel and concrete monuments to process failures or cost overruns. The mining industry has had a spotty record in the area of estimating initial capital costs and operational performance, even though the standard of feasibility studies is generally acknowledged to have improved in the last decades. Third party reviews rarely have the luxury of enough time and unlimited funds, so where should the reviewers focus their efforts to be most effective? Assuming that the project already apparently meets investment criteria, the authors suggest where and how to look among fundamental project parameters for signs that serious flaws exist that have the potential to become project killers. We also give advice on how to review cost estimates without becoming lost in the details. The paper is supported with numerous actual examples.

Jan 1, 2003

By Aylmore M. G

Samples have been taken from a two-stage industrial gold roaster treating a pyrite/pyrrhotite/arsenopyrite concentrate, in order to describe the mineralogy, composition and surface area of the calcines. Sulphides oxidised to produce a porous magnetite in the first stage and a porous hematite in the second; pyrite predominantly roasted via a pyrrhotite intermediate. Sulphur was eliminated in both the first and second stages whereas arsenic was eliminated in the first but retained in the second, partly as rims on hematite particles. The finer sized particles from the cyclones and electrostatic precipitator, while having the greatest surface area, were the most refractory with respect to gold solubilisation, probably as a result of incomplete decomposition (through short-circuiting) in the first stage, and through a combination of factors such as overheating and entrapment of sub-microscopic gold in the second stage.

Jan 1, 1992

Current mine ventilation systems have evolved from simple, limited energy, series or multi split layouts motivated by low suction, slow running, surface fans. Concentration of coal production from fewer working places and ventilation splits, and varying needs, hazards and challenges, however, have led to substan- tial changes. Modern ventilation systems, therefore, are more complex, sometimes more interdependent on others, more energy intensive, and are founded on the use of multiple airways and greater suction, higher speed surface ventilators and often booster fans. Intensi- fication of output has resulted also in higher gas emission rates, the wide adoption of fire- damp drainage, and sometimes in particular problems such as spontaneous firedamp emissions. Some coal mines are subject to spontaneous outbursts of coal and firedamp. These and related matters and current practices and developments are leading to discernible trends, potential advances, and further changes in Practice.

Jan 1, 1983

By Clark GH

Batu Hijau is a porphyry copper-gold deposit located on Sumbawa Island in the western Banda Arc of Indonesia. The deposit has been evaluated from 54000m of drilling in 105 diamond drill holes over a surface area of 1.2km2 and to a depth of 1000m below surface (412m below sea level). A provisional plan is being evaluated to mine 642 million tonnes at an average grade of 0.61% Cu and 0.55g/t Au (variable cutoff) from an open pit in the higher grade portion of the resource. The deposit is associated with a caic-alkaline intrusive complex that was emplaced in a thick sequence of andesitic pyroclastic rocks. The oldest and most widespread intrusion is porphyritic to medium-grained, equigranular, quartz hornblende diorite. At Batu Hijau the western diorite contact zone was intruded by two phases of tonalite. The older tonalite is a stock increasing from 200m diameter at surface to 500m at sea level. It consists of quartz, plagioclase and hornblende phenocrysts set in a groundmass of similar composition. A younger tonalite intrudes the tonalite stock, quartz and plagioclase phenocrysts are more abundant and it has a finer groundmass than the older tonalite. Brecciation occurs near the older tonalite contacts but there are no breccia pipes or late-stage features such as pebbldykes or postmineralisation intrusive rocks.

Jan 1, 1995

By Bourgeois F

The population balance concept has provided a useful framework for the description of the operating behavior of the ball mill. This approach finds expression in the so-called selection breakage function model for batch and continuous mills. This model produces very good descriptions of the size distribution of the products from ball milling operations and the model is very useful for the description of batch and continuous mills and, when combined with models for classifiers and other unit operations, provides a solid basis for flowsheet simulation procedures. The breakage and selection function model is essentially descriptive and not predictive because the parameters in the model cannot as yet be related to the fundamental material properties of the material that is broken and to the fracture mechanics that govern the comminution of brittle particulate material during the rapid impact and compression events that occur with high frequency in a ball mill. The population balance approach smears over the individual processes and regards the ball mill as a continuum with breakage occurring continuously in time and space. New experimental techniques, particularly the adaptation of the Hopkinson bar as the ultrafast load cell (UFLC) to the problem of observing the extremely rapid impact fracture of particulate solids, have made it possible to make accurate and consistent measurements of particle strength, particle fracture energy and the single-impact breakage function. These quantitative measurements have been incorporated into a new conceptual model for the description of the ball mill. The model is based on identifying all events that give rise to particle breakage, and using the fundamental experimental data obtained on the UFLC and other single-particle fracture tests, the probabilities of these events can be independently determined. The distribution of impact energies that occur in the ball mill has been established by discrete element simulation of the media motion. The probabilistic description of the individual fracture events and the distribution of impact energies are combined to make a priori predictions of ball mill performance under a variety of operating conditions. The new model is used to calculate the selection and breakage functions for quartz in a small batch mill.

Jan 1, 1993

Location & Permit Status Three major Mesozoic Tertiary basins exist along the continental shelf area of southeastern Australia, known as the Bass Strait area. They are the Gippsland (east of the longitude of Melbourne) Otway (west of Melbourne) and the Bass (underlying central Bass Strait between Victoria and Tasmania). The total area, both onshore and offshore, is approximately 100,000 square miles. In March 1960, the Broken Hill Pty. Co. Ltd. acquired exploration title to the continental shelf areas of the Gippsland, Bass and Otway basins from the States of Victoria and Tasmania. The title to that part of the Otway Basin in South Australian waters was granted in July, 1961. Other exploration permits, being 8 miles wide in Gippsland, held by Woodside :E.) Oil Co. N.L., and 15 miles wide along the southwest coast of Victoria, held by Mobil-BP-Interstate Oil (Frome-Broken Hill Co. Pty. Ltd.), were in existence prior to granting the B.H.P. title. Subsequently, Shell, B.H.P., Esso and Magellan have been granted title to the remaining areas of the continental shelf in the basins under discussion. In three separate agreeme negotiated between 1964 and-1966, Esso obtained farm-in rights to B.H.P.'s Gippsland, Bass and Ott' Permits.

Jan 1, 1970