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By Lloyd F, Arnold D. A, Hagan T. O

This paper investigates the problems that are encountered in mining at extreme depths. It looks into the rock mechanic aspects, especially the high stress levels that will occur, and the hazard of rockbursts. Furthermore, environmental problems are discussed, with refrigeration and reduction of neat loads being major methods of maintaining ,sorkable conditions. The paper concludes that it will be of tmost importance to have a planning team of Tne highest quality to ensure that conditions are maintained so that work can be carried out safely and under reasonable conditions.

Jan 1, 1986

By J P. van Dijk, M Munro

Discrete vein modelling presents an innovative geology driven 3D modelling method for quantification of vein hosted mineral deposits, with far reaching potential for critical mineral supply and low impact resource extraction. By integrating key geological drivers with advanced discrete fracture network modelling, the DMX protocol (launched in 2019) converges to a more realistic representation of complex vein systems in three-dimensional space. The approach insights greater geologic reasoning in distributing mineral grades where vein boundaries are already defined. This presents a viable alternative to existing modelling and estimation methods and has important implications for mineral resource estimation and reporting. Further implications are discussed, where the enhanced understanding of complex orebody characteristics can potentially be used in optimising mining and mineral processing, supporting more sustainable and efficient mining practices.

Sep 1, 2024

By Howard G. L

The gold treatment plant of Great Western Consolidated N.L. is at Bullfinch, Western Australia, 22 miles north of Southern Cross, which is 100 miles west of Kalgoorlie. A railway to Southern Cross connects the mine with the main Perth-Kalgoorlie line.The plant, which commenced operations on the 31st October, 1952, was, designed by Messrs. Alex: Stewart & Co. in consultation with the technical staff of Western Mining Corporation Ltd. to treat 1,000 long tons a day, made up of approximately equal parts of quarry oxidized ore and underground sulphide ore, by moderately coarse grinding (2-3 per cent plus 65 mesh Tyler) and straight cyanidation without straking. The design had to allow for future treatment of all sulphide ore at the rate of 40,000 tons per 28-day periodand to make provision for the possible later inclusion of preaeration treatment.The test work on .which design was based was done on representative development samples, the mine being divided into zones for this purpose, to check possible local variations from average treatment behaviour. Proposed mill feed mixtures were made up from time to time for complete ore dressing tests, which were conducted in the Western Mining Corporation laboratory at Kalgoorlie.The chief feature of the design was that the plant had to handle the extremes of very soft, poor settling and filtering oxidized ore and very hard, good settling and filtering sulphide ore. On one hand, crushers and mills had to be large enough to handle the sulphide ore and on the other, thickeners and filters had to be large enough to handle the oxidized ores.The design is marked by simplicity, the use of large units of equipment, and flexibility to cope with a variety of ores.

Jan 1, 1956

The Circum-Pacific is defined to include back arcs and continental areas of volcanism. Volcanoes must be regarded as dormant, if the time since their last eruption is less than about ten times the average interval between eruptions, even if they have not erupted for tens of thousands of years or longer. It is important to establish a complete history, over as long a period as possible, for varying volumes of eruptions. In order to assess risk, the average interval between eruptions should be calculated for each range of erupted vo4ume~, in orders of magnitude from about 10 m up to the maximum volume possible at each volcano. Eruptions are considered to consist of individual explosions, and are grouped into eruptive sequences, with the sequences grouped into overall cycles of activity. Frequency of eruption versus volume erupted is a linear relationship for most andesitic and basaltic volcanoes, but is often bimodal at rhyolitic volcanoes, 3 with a slower eruption rate above about 10 km. Worldwide, during the last 7000 years, there have been three known e~uptions with volumes of ejecta of > 100 km , a9d, since 1638 A.D., 7 with volumes > 10 km , and 48 with volumes > 1 km . Average recurrence intervals are about 71 years for eruptions of > 20 km , 39 years for those of > 10 km , and 7 years for those of > 1 km . Rough esti- mates can be made for larger volumes erupted. Mean intervals in the Circum-Pacific are about twice the length of those for the world as a whole. During the last 400 years, about 61% of the world's eruptions of > 1 km3 have taken place in this region.

Jan 1, 1987

By T P. Hynes

Submarine tailings disposal is conceptually an attractive option for managing reactive mine wastes in coastal regions by virtue of reduced sulfide oxidation under a water cover and no infrastructure to maintain after mine closure. However, the lack of detailed knowledge of metal leaching, dispersal of fine tailings and biological impacts in the marine environment has led to no operating permits currently in effect in Canada. Detailed chemical and ecotoxicological assessments at two historic copper mine sites (Little Bay and Tilt Cove) in the north coast of Newfoundland with tailings disposed in an estuarine to shallow (=100 m) marine environment have demonstrated reduced reactivity of sulfidic tailings when submerged under water. Only non-acute toxicity is detected in biota inhabiting the immediate vicinity (A review of another historic shallow marine tailings operation in the southern tip of Vancouver Island (Jordon River) with a high-energy setting also reveals problems with unconfined tailings dispersal and temporal biological impacts. Documented studies at two deeper (140 - 360 m) marine tailings disposal operations at the northern tip of Vancouver Island (Island Copper) and northwestern coast of British Columbia (Kitsault) again illustrate imperfect predictions of tailings re-suspension and dispersal. At these sites, bioaccumulation of tailings-derived metals appears to be minimal. There is evidence of rapid re-colonisation of the tailings surface by benthos but of different species than the original population. Integrating these observations with reported metal fluxes and biological diversity associated with submarine hydrothermal vents, the risks and benefits of deep-sea (>1 km) tailings disposal are discussed. To determine if submarine tailings disposal in deep, confined basins on the seafloor is environmentally friendly, detailed multi-disciplinary research incorporating physical, chemical, biological and toxicological components will be indispensable.

Jan 1, 2003

By A M. Myrvang, B Nøst, N Q. Trinh, I S. B Bergh

The iron ore producer Rana Gruber AS is situated in northern Norway just below the Arctic Circle, and has been producing hematite and magnetite concentrates for more than 60 years. Since the late 1990s, the major part of the production comes from a sublevel stoping underground operation after many years of open pit mining. Despite moderate mining depth, the operations have experienced considerable rock stress problems due to quite high tectonic, horizontal stresses. To manage the problems, comprehensive rock mechanics investigations have been carried out by SINTEF, a major contract research organisation. This has included in situ rock stress measurements, laboratory investigations and numerical modelling. Based on this and practical experience, satisfactory design of vertical and horizontal pillars was achieved. At depth, the ore width increases from 30–40?m to more than 100?m. This, together with a major planned increase in production, called for a change of the mining method. After thorough investigations and considerations, it was decided to change to sublevel caving, very much like the LKAB system. The development of the new system has been closely followed up by rock mechanics measures, including 3D numerical modelling and comprehensive monitoring of deformations and rock stress changes. To achieve a satisfactory caving of the hanging wall, all vertical and horizontal pillars in the sublevel stoping area had to be removed. This has been a challenging task, and the development of the caving has been slow until recently. However, now the caving develops satisfactorily.CITATION:Bergh, I S B, Trinh, N Q, Myrvang, A M and Nøst, B, 2014. From sublevel stoping to sublevel caving at Rana Gruber, Norway – rock mechanical aspects, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 323–330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

Airblast overpressure legislative limits can be extremely difficult to meet throughout Australia, which has by far the most stringent limits of any nation in the world. As the difficulty in meeting the limits is strongly dependent on the scale of mining, it is not surprising that the Australian coal mining industry is experiencing particular difficulties in meeting these limits. Eight full scale overburden blasts have been modelled with respect to overpressure impact for a strip coal mine, involving both dragline (cast) blasting and pre-strip (non-cast) blasting. Overpressure levels in the range 100 to 125 dBL have been measured at distances varying from 2.4 to 5.7 km, and modelling has successfully estimated both the amplitude and shape of overpressure waveforms to within an average of 1.2 dBL. Typical errors of prediction are around 0.6 dBL. This accuracy of prediction has been achieved by considering the impact of only the face holes, and the accuracy of prediction of both shape and amplitude suggests that it is these holes which dominate the environmental overpressure impact at distances in the range two to six kilometres, for cast and pre-strip blasting operations. Modelling has been based upon the Elemental Overpressure Wavelet proposed by Richards and Moore (2002), incorporating actual hole coordinates, actual delay timing, and assumed delay scatter statistics. The incorporation of delay scatter statistics has been particularly significant, and allows the determination of the range over which the peak overpressure levels are expected to vary. To date, modelling has considered only the use of conventional pyrotechnic delays, though simple adjustment to the scatter definition would allow estimation of overpressure levels, and their variability, with electronic delays.

Jan 1, 2004

The Mungana group of mines, in the Chillagoe district, yielded 334,000 tons of ore giving 31,831 tons of lead, 7,907 tons of copper and 3,228,600 ounces of silver. The Girofla mine produced approximately 220,000 tons of ore, and with the Lady J ane mine supplied most of the ore from this centre. The deposit was discovered in 1888, but active development did not commence from the main shaft until 1898. A subsidiary of the New Chillagoe Railway and Mining Co. Ltd., the Mungana (Chillagoe) Mining Co. Ltd., worked the mine from 1902 until 1914, selling copper, copper-lead, lead ores and fluxes to the smelters at Chillagoe. The smelters stopped operations in 1914 when the richer ores of the Girofla had been worked out and production from the Lady Jane had ceased due to heavyground and fire. The Girofla shaft was 823ft. deep with a cross-cut at 810ft. At the 710ft. level contour drives had delineated the orebody, which had been stoped about 10ft. above the level. Except for flux ores which had been stoped only for favourable smelter tariffs, the orebody was practically exhausted above the 610ft. leveL Under company ownership the mine yielded 139,265 tons of an average grade of 4.QlYr copper, 16.2% lead and 12.5 oz. per ton silver.In 1921 the Queensland Government re-opened the mine and worked it until 1927. The North Lode (Fig. 2) was discovered almost immediately at the 100ft. level and was worked down to the 410ft. leveL The ore from this branch and the completion of the stope at the 710ft. level yielded about 80,000 tons of ore averaging 0.4 copper, 9.8 lead and 7.8 oz. per ton silver during this period.

Jan 1, 1953

By D Newton

The Mt Morgan Minesite in Central Queensland has been subject to both underground and surface gold mining operations since the late-1800s. The site is largely unrehabilitated and poor quality surface run-off and subsurface leachate is contaminating the nearby Dee River. The site is dominated by a large open cut, which now stores contaminated surface and subsurface run-off. Three models were used to simulate the complex hydrologic processes occurring at the Mt Morgan Mine: a rainfall-run-off model, a groundwater model and a storage behavioural model. Study results showed that the open cut is filling with water and will soon spill large volumes of highly polluted water to the Dee River on a regular basis if no remedial action is taken. This will result in a three-fold increase in pollutant load to the Dee River. Based on a consideration of water quality and quantity it was concluded that the first priority for future minesite water management should be the prevention of spills from the open cut. Potential management options to achieve this objective included surface rehabilitation, catchment diversions, modification of the pump-back system and controlled releases to the Dee River during floods. However, assessing the relative effectiveness of these measures required a thorough understanding of the complex surface and subsurface hydrology of the site. The results of a 100 year simulation of hydrologic processes revealed that previously favoured management options would be ineffective in preventing spills to the river. On this basis, a continuous treat and release strategy was proposed as the only reliable method of preventing future spills. The results of this study demonstrate that good environmental management decisions must be based on an understanding of the relevant physical processes and consideration of cumulative effects over an appropriate time scale.

Jan 1, 2003

A pilot plant has been constructed for the low temperature carboni-zation of Wallarah (N,S,W6) coal at the rate of 300 pounds per hour. The plant was built and tested at Australian Mineral Development Laboratories for Broken Hill Pty, Ltd. Char product was required within the specifi-cation 15.5 `S' 1 per cent volatile matter. The design was based c atz an entrained state carbonizer developed by Parry and U.S. Bureau of Mines co-workers at Denver, U.S.A. The method involved the carbonizatioan of fine coal by entrainment with air in an externally heated reactor.. The heat required for carbonization of tits coal was supplied to the be, both through the reactor walls and also by internal cambustion of products .

Jan 1, 1963

Unnamed early prospectors panned gold from creeks drain- ing the Great Dividing Range in the early part of 1851. The first publicised discovery was credited to Edward Hargraves near Bathurst in New South Wales later in 1851 and during the ensu- ing gold rush, prospectors rapidly made discoveries elsewhere in New South Wales and later across the border in Victoria. Reference to the attached graphs of gold production indicates that for much of the first 100 years, gold production came from the easily worked and readily discovered shallow alluvial deposits, many of which were located in the creeks draining mountainous regions of Victoria, New South Wales and Queensland (Fig. 1 and 2). As these deposits were exhausted, prospectors turned their attention to outcrop lode deposits which led to the development of underground mining techniques and a significant boost in over- all gold production. With the discovery of the rich Golden Mile lodes in Kalgoorlie in 1893, gold production increased signifi- cantly and peaked around the turn of the century. At that time, the enormous potential of the great Witwatersrand deposits in South Africa had only just been appreciated and for a few years, Australia led the world in gold production (1855-1863 and again in 1903). Underground mining continued in the Eastern Goldfields area of Western Australia, the Bendigo-Ballarat region of Victoria and in northeast Queensland. Very few of these operations continued beyond the Second World War, except the larger producers in the Kalgoorlie region where recovered grade had dropped to about 6 g/t Au. By the early 1970s with the gold price fixed at US$35 per ounce, most of the operations were shut down as labour costs escalated, with only the low cost bulk mining operation at Mt. Charlotte and the high grade reefs at Norseman continuing in Production.

Jan 1, 1988

The object of this paper is not to describe any particular type of engine in close technical detail but rather to give a general picture of past and present practice in this important section of the industry. The subject involves the study of almost 600 years of coal mining history which has fluctuated from stagnation to extremely rapid progress.Up to the year 1300, coal was obtained from outcrops and exposed beds, but this easily worked source soon gave out, so by that time shafts had to be sunk to the coal seams, and coal mining proper commenced its career.These early shafts were very shallow, and winding equipment was not a matter for much concern. Raising coal was generally achieved by human labour, which was called "coal bearing." Coal was loaded into baskets. strapped to a man's back, and carried from the underground workings to the pit bottom. The unfortunate individual then climbed ladders to the top of the shaft, unloaded the basket, and descended the shaft for the next load. Men, women and even children, were employed as the mine expanded, and were generally bound to the colliery for life, performing daily work which would now be regarded as slavery. This primitive method of raising coal to the surface was slow, inefficient and highly dangerous, yet for want of a better method it continued until in 1602 it isrecorded as having been abolished in Wales, one of England's great coal districts. It was not until 100 years later, however, that it was abolished in the northern coalfields, and the colliers were freed forever from their dreadful life.WINDLASSThe first step towards winding coal was the introduction of the windlass. This was similar to the common windlass used over a well, and was operated by man power. The...

Jan 1, 1945

By A Hocking, S Henderson

Commonwealth of Australia (2016) defines rehabilitation as comprising “the design and construction of landforms as well as the establishment of sustainable ecosystems or alternative vegetation, depending upon the desired post-operational land use”. For open cut coal mines in Queensland and New South Wales, the question of how to apply this intent to pits at mine closure is repeated for hundreds of individual pits. In EISs, closure plans and public discussion, assorted treatments are proposed to rehabilitate pits. While some aspects of final voids have been intensively studied, there is little guidance on how to choose a final void treatment option that delivers the optimal outcome against rehabilitation goals. For example, in the Bowen Basin and Hunter Valley commonly proposed rehabilitation actions include reducing the angles of pit walls; however, with few voids successfully rehabilitated to date there is limited understanding of what different wall slopes will achieve.CITATION:Henderson, S and Hocking, A, 2018. A decision framework for comparison of coal void rehabilitation options, in Proceedings Life-of-Mine 2018, pp 127–130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By T Atchison

In-pit crushing and conveying (IPCC) systems have come under growing scrutiny as a perceived mitigation to fuel and equipment price fluctuations, labour shortages and the need to move everincreasing volumes of material. Individual vendors and delivery organisations are now offering a sometimes confusing array of systems, particularly for the dig and dump side operations.One system does not suit all operations. This paper seeks to document the factors that should be considered in assessing the suitability of different IPCC systems, with a focus on dig side equipment layouts in particular. These factors include the productivity of the systems, interactions with the drill/blast and bench operation sequence, the ease of relocation, flexibility to changes in the reserve, scalability and compatibility with other elements of the system.

Jul 11, 2011

A laboratory investigation was carried out to obtain data on the explosive character- istics of selected coals mined in New South Wales. Seven coal seams were sampled and the volatile matter content of the coals tested varied between 28 and 37 percent. A mod- ified Hartmann apparatus with a volume of 1250 ml was used in the investigation. Dust clou' generation was produced by an air blast delivered radially through a mushroom type valve and the ignition source was a-continuous A.C. spark produced by a 20 000 V, 50 mA transformer. The coal dust parameters invest- igated were the maximum pressure developed, the average and maximum rates of pressure rise at dust concentrations between 200 and 1500 3 g/m.

Jan 1, 1981

By A J. Moore

The Australian Coal Association Research Program (ACARP) funded project, No C14057, entitled æEffect of Blasting on InfrastructureÆ, has been carried out with the objectives of providing methodologies for the assessment of the strength of infrastructure types and the establishment of responsible and realistic limits. Personnel from Melbourne, Newcastle and Swinburne Universities and Terrock Consulting Engineers conducted the project. Infrastructure types including: conveyors; power transmission towers; wooden power poles; electrical substations; pipelines, bridges; public access roads and underground workings have been investigated by both field studies and structural analysis. Railways, underground telecom cables, dams and industrial buildings have been reviewed using general structural analysis. This paper has been prepared for the mining industry to provide a progress report on the project.

Jan 1, 2007

Whilst decisions to commit projects have traditionally been heavily influenced by hurdle rates for d.c.f. analysis, it is suggested that evaluation of competitors' costs may be a desirable additional tool.The MICAS system developed over the past four years is described. This computer system uses standard costs modified by District and Mine factors to allow estimation of individual mine costs. The data base contains more than 15,000 items of data and more than 6000 costs are calculated.Recent applications include use for competitive analysis, predictive analysis, statistical analysis, and comparative assessments with scopes ranging from a few mines to the whole Australian export industry. Some areas where care is necessary are outlined and potential further uses are discussed.

Jan 1, 1985

The paper deals with the taking of soundings in connection with coal mining operations under part of the Pacific Ocean adjoining John Darling Colliery.INTRODUCTIONIn the early days of mining in the Newcastle District there did not appear to be any definite law specifying the limits to which mine workings, other than certain borings, could extend under tidal waters.As time went on, a figure of 120 ft. was fixed as the minimum thickness of strata between the roof of the seam and the sea bottom; beyond this mining operations are disallowed. The laws relating to working coal under tidal waters are as follow:-The minimum width of pillars to be left shall be eight (8) yards and the maximum width of bords or other excavations shall be six (6) yards, but the lessee may at his discretion increase the minimum width of the pillars or decrease the maximum width of the bordsor other excavations so as to increase the general safety.The eight (8) yard pillars shall be left unwrought.In on-road of every pair of Winning-off or leading headings, a bore shall be kept going ten (10) feet in advance for the purpose of foretelling the presence of any fissure, wash-out, open joint, fault, dyke, or otherwise, and all winning-off headings shall be driven atleast one hundred (100) yards in advance of the working bords.The most accurate and trustworthy information shall be obtained by the lessee not only' of the depth and character of the ocean bed, river, lake, or estuary deposit, but also of the strata overlying the coal seam.When working under the ocean, strata shall be bored through and proved a minimum thickness of thirty (30) feet at the face of the leading headings or levels immediately such headings or levels are under the ocean, and...

Jan 1, 1947

By H Mansouri, M A. Ebrahimi Farsangi, F Faramarzi

A blast fragmentation model is developed based on the gamma function to describe the run-of-mine fragmentation distribution. The model presented is aimed to benefit from simplicity in application and also to be efficient in description of the fine to coarse part of the blast rock fragments. In fact, the gamma based model (KC-KUM), gives a unit distribution curve, which is made up of two separate equations, covering different fragment sizes in the muck pile. The generated values of the fines to central part of the equation and the central to coarse part of the equation are connected at the 40 per cent grafting point. For validation, eight production blasts, which were specially designed for this purpose, were carried out at an iron ore mine (Jalal-Abad iron ore mine/Iran). Results achieved by KC-KUM and two of the most well-known models. Kuz-Ram and Swebrec, are compared with measured data. Moreover, to assess the models’ efficiency in presenting the best distribution curve, a Logarithmic error method is chosen. Based on the achievements. KC-KUM has the least deviations by the least absolute log error of 0.52, whereas the values obtained for the Swebrec and Kuz-Ram models were 0.79 and 1.34 respectively. Furthermore, the models were applied to predict X80 for 12 production blasts carried out at Gol-e-Gohar iron ore mine/Iran. These predictions were compared with the results from these trials. The coefficient of determination (R2) and root mean square error (RMSE) are calculated. Consequently, the highest R2 was obtained for KC-KUM at 0.837 with the least RMSE of 11.31. On the other hand, R2 and RMSE are equal to 0.832 and 20.19 for Swebrec; and 0.813 and 19.75 for Kuz-Ram respectively. The results obtained suggest the superiority of the KC-KUM model over the other two models in assessment and prediction of blast fragmentation in a reliable way.CITATION:Faramarzi, F, Ebrahimi Farsangi, M A and Mansouri, H, 2015. Prediction of rock fragmentation using a gamma-based blast fragmentation distribution model, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 685–692 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By M Fuchs

Roadheaders were introduced to mining and tunnelling in the early-1960s. Since this period their main field of application has been for roadway drivages in coal mines and for mineral production, for instance in coal, rocksalt, potash and gypsum mines. Their main field of application in tunnelling is in softer and partly friable rock formations, a suitable area for non-blasting excavation. However, in longer tunnel sections excavators with high ripping forces have replaced roadheaders in many situations. The main arguments against roadheaders have been and still are:a sharp increase in excavation cost with increasing rock strength and increasing abrasivity; and greater risks in conditions which have not been, or could not be, investigated to a sufficient extent. These arguments have, to a great extent, restricted practical roadheader application in production mining and in a lot of æstandardÆ tunnel projects. To address these limitations, factors which could make roadheaders attractive for such conditions and could overcome existing technological difficulties have been investigated. Extension of the economic field of application in hard rock was found to be the most important and the most effective step forward.

Jan 1, 2002