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By Heath E, van Calsteren P, Turner S, McDermott F

U-Th isotope studies of recent volcanic rocks may be used to evaluate the depths and rates of melt generation beneath mid- ocean ridges and ocean islands. Island arc rocks exhibit a similar range in Th isotopes to that seen in both MORB and OIB, but while those with high (230Th/232Th) tend to have excess 238U, many of those with low (230Th/232Th) are in isotope equilibrium. The excess 238U is attributed to the preferential mobilisation of U in hydrous fluids from the subducted slab within the last 100,000 years, whereas the low Th isotope ratios in the higher-K arcs are primarily due to the introduction of subducted sediment. Preliminary results from mineral separates from lavas on Soufriere on the island of St. Vincent indicate that some of the minerals crystallised up to 50,000 years prior to eruption.

Jan 1, 1995

By F D. I Hodgson

Twenty-seven observation test pits were excavated at four different spoils dumps at three collieries in the Witbank Coalfield. The holes were dug into the upper three metres of the spoils to ascertain if any weathering profiles, variation with age or influence of topsoil covering could be gauged. Samples from these holes were also subjected to laboratory testing (ABA, humidity cells and mineralogy on several selected samples). The test pits showed that there was a good correlation between in situ paste pH-values and ABA results for samples taken from the pits. At all the collieries, no correlation between age of spoils and in situ acidity could conclusively be drawn. The depth of soil cover also appears to be a minor consideration in determining the eventual acidity of the spoil. In the pits where acidity was found, the weathering was evident when contrasted to areas still buffered. It is unclear if the weathering leads to the acidity or vice versa, as the soil covering appeared to be similar. The spoils proved to be extremely variable with regard to particle size and material on a micro and macro scale. Evidence from most of the holes suggested that there was enough water contained in the fine material in the spoils to support the initiation of acid generation. Conclusions from this investigation are that the mineralogy of the spoils is the most important factor in determining the eventual occurrence of acidic hotspots, and that prior characterisation and selective handling will provide the best management practice for these spoils.

Jan 1, 2003

By Hill G

The Boddington Gold Mine (BGM) is managed by Worsley Alumina Pty Ltd (Worsley) and is located 110 km south-east of Perth, Western Australia. The gold mine, which has operated since mid-1987, was originally constructed to treat 3 Mtpa of gold bearing oxide ores, has subsequently been expanded to treat 7 Mtpa and is presently one of the largest gold producing operations in Australia.During 1990 a Supergene/Basement Plant was constructed to treat 250 000 tpa of copper supergene and hypogene ores and basement ores which contain significant gold grades and which are encountered at the lower levels of the existing oxide orebody. The SupergeneBasement Plant has the versatility to treat a wide range of ore types, producing both gold bullion and copper-gold concentrates. It is a stand-alone facility adjacent to the existing 7 Mtpa gold plant.

Jan 1, 1992

By P York

The study commenced in October 2012, to understand the basic ecology of the spotted-tailed quoll (Dasyurus maculatus) and to confirm whether the species utilise previously mined land on the Mt Owen mine site that was rehabilitated in 1996 to 2011, as part of their home range. The spotted-tailed quoll is a widely distributed marsupial carnivore that is listed as rare or threatened in every state in which it occurs. The species is a forest-dependent marsupial carnivore that occupies a wide range of habitat types (Long and Nelson, 2004).The first part of the study involved trapping a spotted-tailed quoll and fitting the individual with a combined global positioning system / ultra high frequency (GPS/UHF) radio-transmitter collar (Telemetry Solution – Quantum 4000E). The benefit of the GPS/UHF collar is that it records locations (or fixes) at intervals programmed by the user. The UHF component allows the researcher to locate the individual at a frequent interval, and the Quantum 4000E also has a remote download function, enabling the GPS data stored in the collar to be wirelessly transmitted between the collar and researcher. The benefit of this new technology is that the animal does not need to be repeatedly captured to retrieve the GPS data.Daytime searches are also undertaken using the UHF receiver to locate the individual and locations of daytime denning and latrine sites. The location of each den site is recorded using a hand-held GPS. Data downloaded from the GPS collar is then imported and mapped using computer software program ARCGIS (geographic information system), to overlay the data points onto aerial photography.Results demonstrate that threatened species will utilise rehabilitation areas post mining. The data presented will be used to develop a greater understanding of threatened species ecology in and around rehabilitated areas, which will assist in the planning and design of native forest rehabilitation areas.CITATION:York, P, 2014. Mt Owen Mine spotted-tailed quoll study, in Proceedings Life-of-Mine 2014 , pp 591–596 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Aspinall T. O

This paper discusses the identification and assessment of risk for mining developments particularly for open pit mining. A distinction between sensitivity studies and risk analysis is developed, demonstrating the importance of geological and mining engineering judgement -as applied by experienced practitioners to the analysis and assessment of risk in such projects. Technical and financial risk analysis are discussed under: ò mineral resources and ore reserves; ò mining and processing methods; ò project construction; ò financing; and ò costs and commodity pricing predictions.

Jan 1, 1994

By Hommert P. J, Brown B

Early attempts at estimation of stress wave damage in blasting by use of finite element analysis met with limited success due to numerical instabilities that prevented calculations from being carried to late times. An improved damage model based on microcrack growth in tension allows finite element calculations which remain stable at late times. Estimation of crater profiles for blasting experiments in granite demonstrate successful simulations with this model.

Jan 1, 1990

Autogenous and Semi-Autogenous grinding has become an accepted method of reducing primary crusher product to micron sizes in a single or a two-stage grinding circuit. The elimination of secondary and tertiary crusher circuits and sometimes rod mills helps to lower overall operating costs and, in many instances, can make uneconomical projects viable. Selecting AG/SAG Mills have been rather a "hit and miss" affair over the years, but now with the many different types of tests available, accurate mill size predictions can be made, provided the test data is evaluated correctly. This paper endeavours to simplify the process of evaluating test data and sets down some guidelines for designers to follow when selecting AG/SAG Mills.

Jan 1, 1991

By Hargraves AJ

Pre-drainage experiments have been conduct- ed at Appin, Cook, John Darling, Leichhardt, Macquarie, Metropolitan and Moura No. 2 Collieries. Appin (550 m deep) experiences particular gas problems in development drivages, and the almost pure CH4 seam gas makes difficult tiro compliance with statutory maxima in intakes and returns. Patterns of 43 mm diameter drain- a,.;e holes drilled ahead and laterally into virgin coal have improved gas conditions in working places and have allowed tolerable advance rates. Cook, Leichhardt, Metropolitan and Moura No,. 2 Collieries have experienced gas and stress phenomena ranging from conical bursts less than one tonne to full scale instantan- -us outbursts of hundreds of tonnes with tens ,f thousands of cubic metres of seam gas. Gas ~Irainage experiments with patterns of holes up a,, 200 mm diameter have been undertaken with ;,;siness monitors on the coal to establish .lative effectiveness. Incremental flows into mg 43 mm diameter boreholes have investigated drainage patterns relative to length, and at comparative incremental flows have nlicated lowered permeability zones at stress ,.,utments. In some CO2 seam gas areas where iammability problems are reduced to perhaps ii, but where outbursts proneness is increased,

Jan 1, 1982

The Peko copper orebody is associated with a body of magnetite rock which it has partly replaced. The primary ore averages about 9 per cent. copper and 4 dwt. gold per ton and locally IS much richer. It consists essentially of chalcopyrite and unreplaced magnetite, with lesser amounts of pyrite, marcasite, pyrrhotite, cobaltite, bismuthinite, native bismuth and native gold. The earliest formed mineral is wolfram, and the latest formed is goethite, so that the temperature of deposition ranged from about 5000 C. to 1650 C. or lower.Oxidation extends to 270 ft., which is 100 ft. below the present water level. The oxidized ore consists of cuprite and native copper, and has replaced more or less massive chalcocite of a former zone of secondary sulphide enrichment. The present zone of secondary sulphide enrichment extends from about 270 ft. to 310 ft. depth.INTRODUCTIONThe Peko mine is about 6 miles south-west of Tennant Creek township in the Northern Territory, adjacent to a small outcrop of hematite rock that projects above an otherwise featureless "bull-dust" fiat.The copper-gold orebody being developed in this mine did not outcrop. It was first detected in 1950 by a surface diamond-drill hole (DDH.1), which intersected primary copper ore at a depth of 400 to 425 ft. This ore contained from 4 to 11 per cent. copper and 1 to 25 dwt. gold per ton. Since then a shaft has been sunk, and crosscuts and development drives have been opened on the 210..ft., 300-ft. and 400-ft. levels, which are also connected by winzes. Two diamond drill holes sunk from the 400-ft. level have intersected theorebody at about 450 to 460 ft., and a winze from the 400-ft. level intersected the lode from 445 to 500 ft. At this point it is 54 ft. wide, and averages 9 per cent. copper. More recently an inclined surface drill hole (Peko No. 1) has cut the lode at 856 ft. to 921 ft., equivalent to a vertical depth...

Jan 1, 1955

The article, as written, represents a short account of the treatment of the base bullion from the Broken Hill ores, as carried on at Port Pirie, for the recovery of lead, silver, and gold, and for the treatment of by-products. Appended is a short description of the chief facilities of plant which have been adopted to overcome the main difficulties in the refining of lead the Howard press and stirrer. The article is within the limit prescribed by the regulation for the prize offered by the Australasian Institute of Mining Engineers, comprising 30 pages, containing an average of about 200 words per page, exclusive of analyses, photographs, and sketches.The writer desires to thank those to whom he is indebted for their- kindness in affording him every facility possible to obtain the information which he required for the success of such a paper-viz., Messrs. Robertson, Leavens, and Gronow, of the Broken Hill Propritary Co. Limited, at Port Pirie, and Mr. Crowther, of the Adelaide School of Mines, to whom he is indebted for photographs. The difficulty of obtaining fair samples of gold drosses, and the inability to obtain particulars of fuel consumptions, prevents the paper from being as complete as one would wish. The limited length precludes detail, except in more important parts.

Jan 1, 1907

By Rowlands N. J, Zimmermann D. O

The Engel Model search simulator is described with particular emphasis on preparation of input parameters. The computer has a "black box" role in the same way a telephone or radio is a "black box" in communications. A search technique (sensor) is selected and applied in two stages of'search, namely, reconnaissance and detailed. The model relies on knowing and quantifying the parameters of the target sought and the search technique; this is usually done by analogy studies from available literature and experience. The parameters are then balanced by feasibility studies on the search area. Case histories show that the study makes the user aware of what he is likely to find rather than what he wants or needs to find to be viable. Two case histories are presented: one for Mississippi Valley type lead- zinc deposits and another for stratiform copper. The first study showed particular benefits in the input stage and highlighted the fact that one could expect a lot of encouragement by way of interesting results but with little chance of finding the high-grade,

Jan 1, 1974

By B Darlington, L Sandberg, O Vallati

The D47 and D39 Mechanical Dynamic Extra bolts (D47 MDX and D39 MDX) have been developed in response to the ever-increasing demand from the mining industry for rock bolts with high dynamic capacity. To prove such capacity, Sandvik has performed numerous in situ dynamic testing with the unique Dynamic Test Rig (DTR) (Darlington, Rataj and Roach, 2019; Roach, Rataj and Darlington, 2019). To complement the collection of testing data, Sandvik, in collaboration with the Swedish Research Institute for Mining, Metallurgy and Materials (Swerim) have performed additional experiments in laboratory condition using Swerim’s new drop test rig. This rig utilises a momentum transfer method to apply a dynamic load to the bolt. The sample falls together with the mass until the support beam impacts stationary dampers and the momentum energy is transferred to the bolt. Part of the charged energy is released by the dumpers while the remaining portion is absorbed by plastic deformation and/or displacement of the ground support element. The D47 and D39 MDX bolts have been tested at Swerim’s test facility with different levels of input energy. Six tests were performed at the specification energy of 36 kJ and six tests were carried out with the maximum allowable energy from the facility, ie 44 kJ. The bolts confirmed their dynamic performance absorbing the input energy without failure. The D47 MDX bolt absorbed up to 33 kJ with 150 mm displacement while the D39 MDX bolt absorbed up to 35 kJ with 162 mm displacement. This work will present an overview of the drop test rig at Swerim’s facility and a collection of results of the test performed on the D47 and D39 MDX bolts. The test method and results will be analysed and compared to the tests carried out with the in situ DTR.

Nov 29, 2022

As a result of the rapid economic growth in Japan, environmental problems have become a national concern in the latter half of the In 1967, the Basic Lair for Environmental Pollution Control was enacted as a fundamental ::olicy in this field. This lair provided compre- hensive guidelines for the action to be taken pollution prevention. The biggest problem n air pollution of those days was that of the sulphur dioxide content of the atmosphere. Based upon the law, the smelters in Japan have struggled hard to solve this difficult problem. Consequently, the ambient SO2 level has been lowered gradually year by year. At present, the ambient SO2 level is nearly equal to that in the atmospheric background. Furthermore, the fixation ratio of sulphur in Japanese copper smelters has attained up to 99.5 per cent.

Jan 1, 1980

The Black Star lead and zinc ore-bodies, situated in the western zone of mineralisation at Mount Isa occupy an area 2000 ft. long with varying widths from 100 ft. to 300 ft. The strike is N5°W, and the average dip 60° West.To test at depth the potentialities of this area, an extensive diamond drilling campaign was commenced on 16th October 1927. It was continued, with from one to six machines working, until the end of 1931. During this period, 26 inclined holes, with an average depth of 1224 ft, and a total footage of 31,828 ft. were completed. A vertical hole, 2452 ft. deep, for comparative purposes, has been omitted.These drilling operations came directly under the charge of G J Gray, General Superintendent of Mount Isa Mines, and, in the early stages were supervised by E. D. McDermott, of the Mining Trust, London. The foremen, who were in charge of various sections of the drilling operations, were: H Vale, F Bray, J Winston and A A Sanstedt.

Jan 1, 1932

The pilot scale testing of Australian coals for their NO, emissions was carried out at the ACTC to investigate the influence of coal properties, furnace conditions and different NO,, control strategies on NO,, emissions. The NOx emissions for the Australian coals tested were found to vary over a wide range and primarily depended on combustion temperature and excess oxygen conditions. These coals did not exhibit any fundamental difference in NOx levels to other world coals. Under similar combustion conditions, the conversion of coal nitrogen to NO. was found to be best correlated with coal rank parameter, R, max per centage. The use of staged combustion as a control strategy was shown to reduce their NOx levels by 56 - 77 per cent.

Jan 1, 1991

By M Saghaeian, V Sheikhzadeh, R Hejazi

Mining dilution is one of the most important factors affecting the economy of mining projects. Instead of quantifying dilution in mining studies, it is common to assume a general dilution such as 5 per cent for massive deposits. Dilution increases the operating costs in the plant by increasing the tonnage of material to be milled. It prolongs the mine life by reducing plant’s effective capacity. It also reduces the feed grade. In most cases, lower feed grade means lower plant recovery. Dilution also increases the cut-off grade, which in turn reduces the overall ore utilisation of a mine. In this study has been investigated applying pre-concentration by dry magnetic separation for decreasing of dilution impact on reserve estimation and open pit design in low-grade iron ore mine. Based on the preliminary open pit design and assumption 3 per cent as dilution factor, the mineable ore in life-of-mine (measured + indicated) has been estimated with Fe = 25 per cent, SiO2 = 49.7 per cent. Based on the experimental test work on the ore, by dry low intensity magnetic separation of dry HPGR product grinding circuit, it is possible to remove diluted waste material and liberated gangue before concentrate plant, so that around 34 per cent rejected and Fe grade increase from 25 per cent to 33 per cent and by weight recovery 66 per cent. The results of the test work showed that this methodology could decrease largely the impact of dilution in the feed to the plant. It also slightly effect on the reducing of dilution factor impact for open pit design and optimisation and leads to increase the mineable tonnage in the low-grade magnetite iron ore mine.

Aug 24, 2022

Polish coal mines are well equipped with methane monitoring systems,nevertheless the worsening conditions force a continuous impro- vement in the field of environmental monitoring. Application of modern electronic components make it possible to design the new modular telemonitoring system incorporating the best features of the older systems,widely employed in Polish collieries, eliminating their weak points. Several new sensors and portable instru- ments for methane monitoring and early fire detection have been developed and tested in mining conditions.

Jan 1, 1988

By E A. Agorhom, M Beyuo, C Owusu, I Quaicoe

Understanding the mineralogy and liberation of gold particles in an ore is key to the development and optimisation of gold processing operations, being cyanidation or gravity separation. This can be achieved through basic historic geological information, gold deportment studies, chemical speciation and metallurgical test works. The present study assessed the nature of the occurrence of gold particles (mineralogical composition, liberation, associations and surface chemistry) and its effect on the process route (cyanidation and gravity separation) of a typical paleo placer gold ore deposit within the Tarkwaian Rock system. The investigative approach used involved chemical assay, quantitative X-ray diffraction (QXRD) and quantitative evaluation of minerals using scanning electron microscopy (QEMSCAN). The ore samples (A, B, C, D, E, F) used were obtained from six active pits of a gold mine working on this orebody. The results of the mineralogical analysis revealed that the ore is highly oxidised and comprised quartz (>80 per cent) and Muscovite mica (>6 per cent) as the major mineral phases in all the samples. Trace amounts of hematite, kaolinite and todorokite were also identified in all the samples. The chemical analysis showed presence of gold (Au) in all the samples with samples B (3.62 g/t) and C (3.96 g/t) containing the highest concentrations. Trace amounts of copper (Cu), iron (Fe), sulfur (S), aluminium (Al), arsenic (As) were also detected in all the ores. The QEMSCAN mineralogical liberation and gold association results revealed that the gold grains were relatively coarser in all samples (P80 > 80 µm Au in size) except F (P80 < 32 µm Au in size). Gold grains were highly liberated especially in sample B with the majority of the locked gold grains forming complex associations. All the samples responded well to cyanidation and gravity separation except samples C and F, respectively.

Aug 24, 2022

By Longworth C. R

Competing requirements for land usage sometimes make the correct all- ocation difficult. The decision can be complicated by many factors such as local resident pressure, previous government decisions, economic pres- sures and the duration or permanency of the competing land usages. This problem often confronts the extractive industries with consequent delays in granting leases and some- times considerable local dissension. A proposal to extend the high grade silica sand quarry of the Wamberal Sand Company Pty. Limited is a microcosm of these competing requirements. The sand quarry is located on the New South Wales central coast. It is an open pit operation on a near beach deposit of silica sand suitable for flint glass manufacture.

Jan 1, 1976

The sinking of the new No. 3 Shaft being mainly concerned with providing for the continuation of mining operations north of the existing workings, requirements for the shaft and haulage equipment were assessed, having in mind the anticipated needs of the Company in future years, the .available knowledge and probable future trends of the orebody, and also that the shaft would be required to act as a downcast airway for the ventilation system associated with the northern underground workings.

Jan 1, 1957