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By F Soleimani

Coal and gas outburst is a common hazard in coalmines and due to the complexity of its nature, efficaciously predicting the possibility of its occurrence is intricate. The mechanical and gas flow properties of coal, in situ and mining-induced stresses and geological structure are involved in outburst occurrence, whereas suggested thresholds for its prediction do not consider them all. Numerical modelling is known as an effective method that can not only consider couple the effect of different physics but also analyse the effect of associated parameters. In this paper, a coupled fluid flow and geomechanics model has been developed in COMSOL Multiphysics to simulate outbursts by considering the effect of gas pressure and composition, damage mechanics on related coal properties, and progressive excavation and mining-induced stress. For the proposed fully coupled outburst model, the effect of pore pressure and sorption are applied to the stress while the influence of stress changes and damage are considered in updating coal porosity and permeability in each time step. In addition, to study the effect of mining-induced stress, the excavation process is simulated by changing the material properties over time according to the schedule of heading development. Then, outburst initiation is analysed from the energy point of view by using the concept of energy conservation law. The simulation results are used in calculating energy sources of the outburst initiation, also, the effect of particle size and ejection velocity are studied, and the significance of particle size effect on the energy analysis and deformed coal on outburst initiation is discussed.

Oct 12, 2022

By C M. Zammit, N Cook, F Reith, C L. Ciobanu, J Brugger

The role of biological agents in the gold mining industry is currently limited to the use of microorganisms in bioleaching and bioremediation. However, there is a variety of possibilities in which biotechnology could aid the mining industry in the future. In this article we discuss the potential for the development of these novel biotechnologies and the role they can play in the exploration for new gold deposits, the processing of ores and the post-mining remediation of sites. The development of these biotechnologies has been enabled by rapid advances in our molecular-level understanding of the role microorganisms play in the solubilisation, dispersion and precipitation of gold. An understanding of the distribution of microbial species in soils overlying mineralisation can be utilised to develop bioindicator systems that assist with gold exploration. An in-depth knowledge of how microorganisms interact with gold complexes is being used to develop in-field biosensors, supporting exploration. Processing technologies may be improved based on advances in our understanding of the interactions between microorganisms, ore minerals, cyanide and gold. For instance, cyanide-producing microorganisms are being investigated for use in in situ leaching of gold. In turn, the use of cyanide-utilising microorganisms for the degradation of cyanide is being explored. Combined, the implementation of these biotechnologies in the gold mining sector may revolutionise the industry, leading to greener, more efficient exploration for and extraction of gold.CITATION:Zammit, C M, Cook, N, Ciobanu, C L, Brugger, J and Reith, F, 2013. Possible future applications of biotechnologies in the gold industry - a prospective approach, in Proceedings World Gold 2013 , pp 233-244 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

In order to understand the technique, basic theoretical principles of radiation emission and in- strumentation theory are reviewed. Methods of surveying, reduction of data and interpretation are outlined. Other applications of the technique (e.g. in airborne geological mapping), as well as its specific use in uranium exploration, are discussed. By means of case history-type examples the successful applicant of gamma-ray spectrometry, as a tool in Australian mineral search, is demonstrated.

Jan 1, 1969

By Tarvainen M, Mattila O

Outokumpu Oy has systematically developed the automation of mineral flotation covering the technology of both new devices and control methods, and as a practical result of this effort currently produces two on-stream X-ray analyzers. The Courier 300 system basing on conven- tional X-ray technology is applied to complex or large processes. The newer Minexan 202 dis- tributed probe system based on radioisotope technology is developed mainly for simple or small scale applications. In this paper aspects and experiences of these analyzer systems and their applications for flotation control are discussed with particular reference to the role of the computer

Jan 1, 1977

By P Kirsch, P Jagals, D Viswanathan, J Shandro, R LaBouchardiere

The planning, design and operation of mines must include the development of positive environmental, community and land-use benefits if it is to achieve good corporate social responsibility and minimise detrimental impacts throughout the life of the mine. Life-of-mine (LOM) planning should, therefore, consider conducting mining activities in the best socially, environmentally and economically acceptable manner, from the commencement of exploration to post-closure of the mine. Current knowledge of LOM activities in relation to public health (life-of-community, or LOC) impacts neither fully captures the full suite of human health and well-being impacts, nor comprehensively informs society on these issues. This knowledge gap is becoming more apparent as public antipathy is increasing towards mining activities within Australia, Canada and globally. The purpose of this paper is to present preliminary and informative results of a literature review to gain insight into the extent of available public health and well-being knowledge associated with mining development. LOM development must also benefit the LOC, in that it must aim to minimise detrimental impacts, and maximise beneficial (including health) impacts on all associated communities. Health planning and programing for mitigation of potential adverse health impacts of mining should extend beyond the scope of work-related injury and illness (resulting from chronic exposure to harmful substances, infectious and lifestyle illnesses), to the health and well-being of workersÆ families and extended associated communities. By mapping the available but rather scarce literature on LOC areas to recognised LOM stages, this review found shortcomings and imbalances regarding research reporting on mining and its health-related impacts in the worker-to-community continuum.CITATION:Kirsch, P, Viswanathan, D, LaBouchardiere, R, Shandro, J and Jagals, P, 2012. Health impacts extend from the life of a mine to the life of a community - Knowledge gaps, in Proceedings Life-of-Mine 2012 , pp 161-168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

Elastomeric compression gaskets for segmental tunnel liners are capable of fulfilling all sealing requirements for one pass constructed tunnels.Once the segments are mounted and the gaskets are compressed the watertightness of the tunnel is guaranteed at once and for the whole technical life time.The only prerequisite for effective sealing is that tolerances in the tunnel segments be kept within reasonable limits.

Jan 1, 1993

By Matsushita Y, Maeda M, Sano N

The present study was carried out to explore the possible separate recovery of iron and phosphorus (as gas) from BOF slag using graphite crucibles or graphite powders in the presence of a tin bath. The last is consider- ed to enhance the activity of phosphorus in iron reduced from slag or not to absorb the phosphorus vapour readily. When the slag was reduced in a graphite crucible in contact with a tin bath, the phosphorus reduced from the slag was carried away in CO explosively generated by the reduc- tion of iron oxide. When graphite powder was used as the reductant instead, 78% of the phosphorus was removed from slag, only 3% of which was absorb- ed into the tin bath. The rest left the system as gas. Gaseous dephosphorization depends on the area of contact between slag and reductant as cll n.u the amount of the latter. the reduction behaviour was directly observed, using an X ray transmission technique, to conlirm the reaction mechanism.

Jan 1, 1980

By Dawson CF

About 17% of the world's present day oil supplies comes from wells drilled in the continental shelf of some 28 countries. The demand for oil is increasing each year and is expected to quintuple in the next decade. In the same period, the demand for gas will climb to at least 20 times its present rate. In the next decade, the percentage of oil and gas obtained from offshore is expected to rise to nearly half the world's consumption. The offshore oil industry is currently striving to achieve new technological advances in the field of deep ocean operations, especially in face of adverse seas. While the emphasis was put on drilling vessels for exploration, the industry was slow in developing effective offshore construction vessels. Until a year ago, construction vessels were but large barges with construction equipment mounted on their decks. These vessels all shared the same severe limitation: When the sea exceeds a five-foot wave height (and in some cases as little as three feet) the conventional construction barge is forced to suspend operations. In face of an oncoming storm they must run for shelter. Their utilization, therefore, is limited and in rough weather areas, such as the North Sea or the Bass Strait is lower than 50%.

Jan 1, 1970

By H R. Phillips

Fresh air intake in an underground coal mine is of critical importance to the occupational health and safety of workers due to the dynamic, confined and dangerous nature of the mining environment. In most coal mines in South Africa, belt road is not separated from the fresh air intake to the sections. Intake air to coal production faces generally contains dust generated by conveyor belts, transfer points and travelling roads. Long roadways (up to a few kilometres in some of the existing mines) to the coal sections are involved in the ventilation circuits of individual sections. This leads to a progressive increase in the dust levels in the intake fresh air and thus high dust levels in the air delivered to the working sections downstream. In the process of reducing worker exposure to dust in the face area, attention to the monitoring of fresh intake air is generally given a low priority. This paper summarises the intake dust levels measured in selected South African underground coal mining sections over the past five years and its use as a parameter in assessing worker exposure to dust through a newly developed model called the Dust Exposure Level Index (DELI). Based on the measured data of the South African coal mines, the average section intake dust level was 0.78 mg/m3. Approximately 60 per cent of the samples collected for the study have exceeded the 0.5 mg/m3. The intake dust level measured at a longwall face was much higher than in the CM headings. The measured section intake dust levels furnish the South African coal mining industry with the latest depiction of the level of face area dust contamination due to the intake air. Further, this paper demonstrates the use of intake dust level as a parameter in estimating exposure levels of workers, as it clearly plays as a corner stone in effective control of exposure to face area respirable dust. It must be borne in mind that intake dust is a base level to the mine worker exposed to dust without carrying out any additional work in the section. If the intake air is seriously contaminated by airborne respirable dust; then the exposure of the workforce in the section will constantly be elevated by that background dust level.

Jan 1, 2005

By A Salama, J Greberg, B Skawina

In today’s underground mass mining, the orepass is an important part of the infrastructure as it connects two or more mine levels and is used for conveying or storing large amounts of material. One of the main risks related to an orepass is when operational or structural failure occurs, leading to long-term loss of functionality. Developing or rehabilitating an orepass when major failure has occurred is a time-consuming and expensive operation, and the risk of a long-term orepass loss motivates the development of alternative transportation strategies to ensure the continuation of smooth operations in large underground systems. The study presented in this paper has been done at the Loussavaara Kiirunavaara AB Malmberget mine in Sweden, where iron ore deposits are being extracted using sublevel caving. The study analyses the transportation system in one of the mine’s orebodies using discrete event simulation, with a focus on maintaining ore transportation in the event of the loss of an orepass.CITATION:Skawina, B, Greberg, J, Jonsson, K and Salama, A, 2016. Orepass loss mitigation approach in Malmberget mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 617–622 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By F K. R Klose

Malmberget is a sublevel caving mine owned and operated by Luossavaara-Kiirunavaara Aktiebolag (LKAB), a Swedish state-owned iron ore mining company, in northern Sweden. The mine has an annual iron ore production of approximately 15 Mtpa. The current strategy foresees an expansion which will increase the mine’s depth considerably. Ventilation and air conditioning modelling for the planned expansion is ongoing. One of the most influential parameters for ventilation planning anddesign for a deep mine is geothermal gradient, which is crucial for the design of the refrigeration system. It is determined through virgin rock temperature (VRT) measurements carried out at various depth below the surface. This paper details these measurements and the determination of geothermal gradient for Malmberget Mine for the expansion study, which were necessitated by thelack of information for the focus depth and area.

Oct 12, 2022

The Prominent Hill copper-gold deposit is located approximately 150 km north west of Olympic Dam, on the southern margin of the Mount Woods Inlier in South Australia. Its discovery in November 2001 resulted from the application of a geological model developed from geological, geophysical and petrophysical data pertaining to the Olympic Dam deposit. The discovery has dispelled the notion the Olympic Dam may be unique, and that another deposit like it is unlikely to be found. The Prominent Hill mineralisation is hosted by haematite-matrix hydrothermal breccias, which have suffered extensive iron-sericite-silica alteration and overprinting. Copper, gold, barium, fluorine, uranium, cerium and lanthanum are all intrinsically associated with the hydrothermal iron. Breccias intrude an east-west striking, fault-controlled sedimentary succession, which is flanked to both the south and north by volcanic complexes. Many similarities between Prominent Hill and Olympic Dam are documented including geological setting, mineralogy, breccia styles, and alteration. Differences relate largely to the nature of the immediate host rocks. The similarities and difference provide key data for improving exploration models for this style of iron oxide copper-gold deposit, both within the Gawler Craton as well as globally.

Jan 1, 2004

Answers to the questions "which rocks contain diamonds?" and "which indicator minerals should diamond explorers look for?" are no longer so easily obtained, now that diamonds are known to occur in lamproites and various types of lamprophyres, as well as their traditional source of kimberlites. One way of isolating those factors (host-rock"geochemistry, geographical or tectonic location, xenolith minerals, etc.) which are most critical in determining the diamond potential of a given pipe, is a detailed and critical re-examination of the huge volumes of accumulated data on kimberlites, lamproites and related rocks. A large analytical database to this end has been set up on an Apple Macintosh II microcomputer using the quasi-relational database management system 4th Dimension. Currently, it contains data for up to 90 major and trace elements, isotopic ratios and contained mineral compositions for some 4,000 rock specimens from all over the world. Many experiences in setting up this database are probably relevant to other geologists setting up their own systems: they include determining the relationships between data items; the advantages of codes over free text in representing categorical variables such as rock types; the need for rigorous error trapping and data validation; and the problem of missing data values and ambiguities thereof. The working system is now being used in a rigorous statistical assessment of the criteria which distinguish diamondiferous from non-diamondiferous rocks.

Jan 1, 1989

Blasting, particularly bench blasting, uses finite length cylinders of explosive close to two free faces. The rock to be blasted is usually intersected by a complex 3-D system of joints. To fully simulate a blast, a 3-D dynamic model is required. It is shown that the static stress distribution around a long cylinder can be reproduced by superposing the static stress distribution of a suitable chain of spheres. Thus, the dynamic results for individual spheres given by Favreau (1969) can now be substituted for the static results to give a dynamic model of the stress distribution around a long cylinder. Comparison of measured and computed waveforms show that the measured waveforms are much more attenuated and dispersed than expected. The consequences for explosive evaluation and design are Discussed.

Jan 1, 1990

By C Morley, B Costello

In 2002 the Argyle Diamond Mine upgraded the process plantÆs recrush circuit to include a High Pressure Grinding Roll (HPGR), or High Pressure Rolls Crushers (HPRC) as they are termed in the diamond industry. HPGR have generated considerable interest over the last decade, though there are still technical/processing unknowns to its effectiveness as a primary diamond ore crusher.The upgrade of the Recrush circuit at Argyle Diamonds has gone a long way to answering some of the key questions, and thus it has reduced the unknowns to a level more acceptable to the industry.This paper focuses on the results from the HPRC at Argyle, in particular the performance of the studded wear surfaces, comparison of energy efficiency against traditional quaternary cone crushers and the resultant increased liberation. Issues that have arisen, including edge wear of the studded surfaces, will be discussed and the steps taken to reduce this issue are presented.

Jan 1, 2004

By X Liu

The crystal chemistry of carbonate in Ca apatites, including Na-free and Na-bearing hydroxylapatite (CHAP) and Na-bearing fluorapatite (CFAP) and chlorapatite (CCLAP), has been investigated by Fourier transform infrared (FTIR) spectroscopy and single-crystal X-ray structure, using crystals synthesised from carbonate-rich melts at 1 GPa, 1400 - 1000¦C. The carbonate ion substitutes for both the X (OH, F, Cl) anion species in the apatite channel (type A carbonate) and the phosphate group (type B carbonate). The type A carbonate ion is oriented in the channel with two oxygen atoms close to the c-axis, and the type B carbonate ion is located close to the sloping faces of the substituted phosphate tetrahedron, with details varying with composition series. Sodium promotes the uptake of type B carbonate and also has a profound effect on FTIR spectra. Crystal compositions correspond approximately to the substitution formula Ca10-(y+z)Nay z[(PO4)6-(y+2z)(CO3)y+2z][X2-2x(CO3)x], with x + y up to 1.0 and z + 0.0 for CHAP, x + y + 4z + 0.4 for CCLAP, and x + y + 2z + 0.1 for CFAP, for equivalent conditions of synthesis. The sodium cation and A and B carbonate ion defects are locally coupled in all three composition series to facilitate charge compensation and minimise the effects of spatial accommodation. Synthetic Na-bearing type A-B CHAP with x + y + 0.5 has a similar chemical composition and FTIR spectrum to biological apatite.

Jan 1, 2008

By L Soebari, W Sunyoto

The Wabu Ridge Gold Skarn deposit is located at elevations of up to 3100 metres above sea level, in the Central Highlands of Irian Jaya, Indonesia, 35 km NNW of the Grasberg porphyry deposit. Wabu is a grass-roots discovery in an area with no previous gold mining history or record of gold mineralisation. A geological resource of 117.26 million tonnes at an average grade of 2.16 g/t Au (1.0 g/t Au cut-off) has been defined to-date. Mineralisation is hosted within a skarn occurring along the southern boundaries of the Late-Miocene age monzonite-diorite Pagane intrusive complex. The intrusive complex occurs in the footwall of a major EW structure, the Derewo fault, which displays sinistral strike-slip and reverse fault movement. The Derewo fault separates Derewo metamorphic units to the north from platform sediments of the Australian craton to the south. The skarn has a strike length of 6 km and is up to 1.5 km wide. It is developed within calcareous shelf sediments of the Tertiary New Guinea limestone group and is dominated by prograde garnet development. Gold mineralisation was deposited during retrograde alteration and is directly associated with arsenophyrite and bismuth minerals. Retrograde alteration is distinguished by a sequence of clinopyroxene , magnetite, epidote and hornblende, biotite and chlorite and lastly carbonate. Gold is associated with the biotite/ chlorite phase together with sulphides and precipitated as the result of fluid mixing. The Wabu Ridge Gold Skarn deposit was identified in April 1990 during a regional program of helicopter assisted stream sediment sampling of -80 mesh (180 microns) fraction and panned concentrate sampling. The initial discovery sample site was situated 15 km down stream from the deposit and returned 1.49 ppm Au for the stream sediment sample and 138 ppm Au for the panned concentrate sample. A regional airborne helicopter magnetics survey, conducted in early-1992, helped defined the main magnetite associated skarn zone and the extent of associated igneous rocks. Detailed follow-up commenced in May 1992 and consisted of detailed mapping, soil sampling and ground magnetics prior to drilling the first hole in October 1992. Drilling to-date has delineated a contained geologic resource of 8.1 million ounces of gold and potential exists for a larger resource.

Jan 1, 1999

By Marquez W

Trace fossils have been found in Bolivian Silurian sediments in "La Iumhre" area close to La Paz-Bolivia.Tracks, are good indicators of depth and environment. A detailed study of the ichnogenus is made.The depth and environmental deposits are analyzed to determine the facies. It was shown that the trace fossils of Silurian sediments in La Paz belong to the Zoophvcos and Nereites facies.

Jan 1, 1990

By Lorenzen L, Van Der P F

It is the aim of this paper to review recent research in understanding the role of cyanide in the elution of gold. Under conditions of severe pre-treatment (high temperatures and levels of cyanide), the dynamics of elution are determined mainly by the adsorption equilibrium and the flow conditions in the column. When conditions are less favourable for desorption, transport phenomena are rate controlling. The most important sub-processes of elution are the changes in cyanide, potassium and gold concentrations, as well as the change in passivation of the carbon surface. Mathematical models to simulate the various sub-processes are described briefly.The presence of an irreversibly adsorbed species such as AuCN on the carbon is determined mainly by the pH, temperature and the type of carbon. Cyanide in the pre-treatment step will convert the AuCN to reversibly adsorbed Au(CN)2. Competition between cyanide and Au(CN)z for adsorption sites will enhance the elution of gold, but plays a minor role at elevated temperatures. The most important effect of cyanide is its reaction with the functional groups on the carbon to passivate the surface for the adsorption of anionic metal cyanides and thereby promote the elution of gold. This passivation, caused by the degradation of cyanide, is strongly temperature dependent. Free cyanide in the elution step of an AARL elution is of lesser importance than the cyanide in the pre-treatment step. Elution without cyanide is possible only after cold acid washing, and has been proven on plant scale.

Jan 1, 1992

Daily geological mapping of the Panguna porphyry copper/gold system since mining began in 1971 has provided a good basis for resource estimation and mine planning as the mine and estimation methods have advanced. Geology defined during evaluation and early mining has been substantiated and many smaller features have been better defined or identified. Breccias, pebble dykes, major structures and location of lithology contacts important to short term planning and long term pit slope stability have been defined. Correlation of copper and gold with breccia zones is quite striking and was not fully appre- ciated at the end of evaluation. Pit mapping geology, and diamond drill geology and assays, are now routinely added to a Geological Data base on computer, which forms the major geological data base for modelling the deposit. Geology from diamond drill logging, updated by pit mapping, and assays from diamond drilling updated by blast hole assays have been incorporated in a 45 bench deep 486 000 block computer based block model which forms the basis for long and short term planning. The introduction of pre-concentration scre- ening, based on the distribution of mineralisat- ion and fracturing, puts more emphasis on the definition of grade distribution at low concent- ration and on structures in the rock. Geostatistics is now used for resource estimation and has produced acceptable estim- ates. but these need to be refined, particularly in peripheral, low grade areas of the deposit.

Jan 1, 1987