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The decrepitation technique is a rapid means of measuring abundances, temperatures and to some extent the fluid compositions, of fluid inclusions in transparent and opaque minerals. The method has been used to investigate the hydrothermal fluid systems associated with gold mineralisation in the Tennant Creek, Pine Creek and Halls Creek Goldfields. At the Enterprise Mine, Pine Creek, several different stages of quartz veining are distinguished and within these, gradational changes in fluid temperatures and compositions help to define the centre and nature of the thermal system responsible for the mineralisation. In the surrounding Pine Creek region and at Tennant Creek and Halls Creek, the results were applied on a regional scale to characterize outcrops and aid in the discrimination between potentially mineral- ized and barren outcrops. The decrepitation method involves the heating of a small (lgm) sample of crushed and sized grains up to as high as 800 degrees celsius. During the heating the fluid inclu- sions within the grains develop sufficient internal pressure to physically burst, the temperature of such bursting being dependent on the type of fluid and the prevailing tem- perature at the time the inclusion was originally trapped. The resulting tabulation of the number of inclusion bursts per 10 degree temperature interval is plotted as a histogram of decrepitations versus tempera- ture and called a decrepigram. The decrepi- grams frequently show several distinct peaks at different temperatures which are caused by different populations of inclusions in the sample. The areas of the peaks indicate the abundances of inclusions in each population while the shape and mean temperature of the peak provides a guide to the type of fluids involved. Of particular importance in this study is the presence of decrepitation peaks at fairly low temperatures (around 2000 C. These are characteristic of C02 rich fluids which build up internal pressure very quickly when heated. The Enterprise Gold Mine at Pine Creek comprises a number of overlapping quartz vein systems hosted by Burrell Creek Formation sediments. The geology of this mine has been described at this conference by Dann and Delaney, who have defined several distinct stages of quartz veining based on structural, mineralogical and physical features of the veins. For this decrepitation study, 19 quartz samples from the mine and environs, including some from each stage of veining were collected. These results suggest that there are 4 major vein types, within 3 of which additional small variations can be discerned which are due to gradational changes in the temperatures and fluid compositions in the mine area.

Jan 1, 1984

By Stewart R

Potential acid rock drainage from the destruction of metalliferous sulph-ides is recognised as a critical factor in the design and economics of any mining venture. While this realisation is relatively new, mining companies have embraced the issue with the aim of scientifically quantifying the magnit-ude of the problem, specific to indiv-idual properties.Coinciding with the development of the open pit mine at Porgera, a comprehensive assessment of the potent-ial for the formation of acid rock drainage was initiated in 1991. Detail-ed study of the mineralogical charact-eristics of all rock types, along with extensive test work to determine the maximum potential of rocks to generate and consume acid (known as acid base accounting or ABA), has been conducted. Correlating this with the known and interpreted geology of the open pit has indicated a strong relationship between rock type, sulphur content and the acid base character. This relationship is used daily as a simple, cost effective means for classification and management of the variety of material types produced from the minincx operation.

Jan 1, 1994

By J L. Merritt

Effective minesite water management requires that this issue be treated as a risk management exercise. The management process is generally far from simple and by necessity must involve a range of personnel covering a siteÆs commercial, operational and environmental interests and responsibilities. The challenge to be collectively faced by these stakeholders is to strike the correct balance between risk and cost. On the other hand, the challenge to be faced by technical services support personnel is to provide stakeholders with information in a format that they can use with confidence. This paper presents the application of continuous operational simulation (OPSIM) modelling techniques to establish appropriate risk profiles for minesite operations. It is necessary that the format of these risk profiles be generic and equally applicable for defining the risk of occurrence for a relatively comprehensive range of activities û eg from of a non-compliant discharge, to the risk of failure to meet production targets. What is more, the profiles need to be quantitatively based and capable of reflecting change in system response to varied operational or management strategies. The techniques presented in this paper are based around a key assumption that long-term records of the climate contain within them sets of sequences that are representative of what can be expected in the future û that is, the droughts, floods, cyclones, good years and bad, long or short, and everything in between. Therefore, if these historical records are run through an OPSIM model for a particular site, then the simulated operational characteristics can be taken as being representative of what can be expected in the future, in the long-term. This lends itself to statistical analysis and translation into the required risk based format. Water Solutions Pty Ltd have been working with Capricorn Coal Management to develop a relatively comprehensive OPSIM model of their operations at German Creek Mine, Central Queensland. Outcomes from the modelling have been used in recent times to provide mine management with risk-based guidelines for both securing and containing mine water inventories. One of the more interesting tasks has been to establish risk based inventory levels that, if reached, would trigger the immediate implementation of a contract for the desalination and re-use of mine water, at predefined rates. Also, lead-time warning of the occurrence of a possible trigger is of importance to operational and commercial planning. To service this requirement the OPSIM model is regularly used to produce lead-time estimates to defined levels of confidence. Case studies of these, and other, applications of the OPSIM model at German Creek Mine are presented in this paper and serve to demonstrate an effective methodology for practical risked based water management.

Jan 1, 2003

By V P. Beskrovnaya

Tests for the development of a metals recovery technology from samples of a Russian gold-bismuth deposit were carried out. Gold, silver and bismuth assay reported 5.6 g/t, 3.0 g/t and 0.08 per cent, respectively. Two flow sheet options were pilot plant tested: gravity/cyanidation of gravity tailings with subsequent flotation of cyanidation/carbon-in-pulp (CIP) tailings, and gravity/flotation concentration with cyanidation/CIP of concentrates. Option 1 results showed lower gold, silver and bismuth recoveries (81.3 per cent Au, 55 per cent Ag and 74.0 per cent Bi) due to low flotation efficiency for cyanidation tailings. Therefore, a flow sheet involving gravity/flotation concentration to produce bismuth-gold concentrates (0.8 per cent Bi) with subsequent cyanidation/CIP was recommended. Gold, silver and bismuth recoveries obtained by this method to the combined gravity/flotation concentrate were 90.2 per cent Au, 83.3 per cent Ag and 80.2 per cent Bi of the ore, respectively. Overall gold, silver and bismuth recoveries were 83.0 per cent Au, 40.5 per cent Ag and 80.2 per cent Bi, respectively. Gold and silver recoveries to the cathode precipitate were 92 per cent Au and 48.6 per cent Ag (per operation). Reagents consumed for flotation were 0.1 kg lead acetate/t ore, 0.4 kg butyl xanthate/t ore, 0.2 kg T-80 frother/t ore, 0.02 kg sodium hexametaphosphate/t ore, 0.15 kg copper sulfate/t ore. Reagents consumption for cyanidation was 0.42 - 0.48 kg NaCN/t ore and 0.2 kg CaO/t ore. It was recommended to deliver bismuth concentrates after hydrometallurgical treatment to a smelter. Overall bismuth recovery including bismuth recovery achieved by pyrometallurgy was 60.0 per cent. However, it was obvious that delivery of bismuth concentrates to a smelter and their commercial treatment would be very expensive due to relatively high mass pull of bismuth concentrates (7.6 per cent of the ore weight). For this reason, thiourea leaching and hydrochloric acid leaching with subsequent cyanidation/CIP were investigated as alternatives to cyanide leaching. These two alternatives were proposed to enable optimal recovery of valuable metals from concentrates on-site. Recoveries obtained by thiourea leaching were 91.2 per cent Au, 90.5 - 91.9 per cent Bi and 77.0 - 78.1 per cent Ag. However, that method required considerable capital and operating costs. As an alternative, hydrochloric acid leaching with subsequent cyanidation was investigated. Test results showed improved gold, bismuth and silver recoveries, which were 94 - 95.9 Au per cent, 94 - 96 Bi per cent and 76 - 78 Ag per cent, respectively. Hydrochloric acid consumption was 100 kg/t concentrate or 7.6 kg/t ore. Current efficiency during electrowinning was about eight to 12 per cent. A recommended flow sheet involving hydrochloric acid leaching of concentrates, electrowinning of bismuth from solutions, recycling solutions after electrowinning and cyanidation of hydrochloric acid leaching cakes is described. Overall recoveries achieved by the proposed flow sheet were as follows: 84.8 - 86.5 Au per cent, 75.8 - 76.9 Bi per cent and 63.2 - 64.9 Ag per cent. Based on results from these tests, initial data for a bankable feasibility study and plant designing were developed.

Jan 1, 2007

pNumerical modelling has been used to examine the relationship between the results of two commonly used methods of assessing the propensity of coal to spontaneous combustion, the R70 and Relative Ignition Temperature tests, and the likely behaviour in situ. The criticality of various parameters has been examined and a method of utilising critical self-heating parameters has been developed. This study shows that on their own, the laboratory test results do not provide a reliable guide to in situ behaviour but can be used in combination to considerably increase the ability to predict spontaneous combustion behaviour./p

Jan 1, 2005

By Y Wan, L Liao

Organo-montmorillonites were synthesised by intercalating different amounts of dodecyl trimethylammonium bromide, cetyl trimethyl- ammonium bromide and stear trimethylammonium bromide into montmorillonite layers, and were used for the adsorption of 17b-estradiol in aqueous solution. The adsorption kinetics and thermodynamic of 17b-estradiol onto organo-montmorillonites and the effect of pH on the adsorption capacity of organo-montmorillonites for 17b-estradiol were studied. The adsorption isotherms at 20¦C, 35¦C and 50¦C were measured. Results show that organo-montmorillonite has a high affinity for 17b-estradiol. More 17b-estradiol can be adsorbed on to organo-montmorillonite and the adsorption is more rapid at a lower temperature. The montmorillonite intercalated with cetyltrimethyl- ammonium bromide with the amount equivalent to one times of its CEC has the highest adsorption capacity. For all organo-montmorillonites synthesised in this study, an optimum pH (around nine) for the adsorption of 17b-estradiol exists. Before this pH 17b-estradiol uptake increased with increasing pH. After that the 17b-estradiol uptake decreased with increasing pH. Simulation of the isotherms indicated that the adsorption of 17b-estradiol onto organo-montmorillonites is a spontaneous and exothermic process. Endocrine-disrupting chemicals (EDCs) are the focus of current environmental concern, as they can cause adverse health effects in an intact organism, or its progeny, subsequent to endocrine function. Most EDCs are man-made organic chemicals (industrial chemicals, crop protection products, antifouling compounds, pharmaceuticals and personal care products). In addition, EDCs can be naturally occurring in the environment (eg the natural female hormones estrone and 17b-estradiol). Therefore EDCs, especially estrone and 17b-estradiol, are ubiquitous in the aquatic environment receiving sewage inputs. Estrogen and 17b-estradiol are among the most potent of all EDCs and are sufficiently stable to survive present sewage treatment processes and are reactivated during those processes through deconjugation (Clara, Strenn and Saracevic, 2004; Zhang and Zhou, 2005; Fukuhara et al, 2006; Butler and Guilbault, 2006; Volpe et al, 2006; Ren et al, 2007; Zeng and Li, 2007). In comparison to traditional contaminants such as pesticides, the concentrations of the most potent EDCs are low, generally within ng/one range. The current sewage treatment processes have limited capacity in removing certain EDCs (eg 17b-estradiol, C18H24O2) It is therefore essential to install additional treatment processes to remove them from wastewater before discharge (Zhang and Zhou, 2005; Fukuhara et al, 2006; Lee, Jung and Kim, 2006). Adsorption is considered to be a possible way to remove EDCs from aqueous solution. Various adsorbents have been studied, including chitin, chitosan, ion-exchange resin, activated sludge, activated carbon (Clara, Strenn and Saracevic, 2004; Yoona and Westerhoffa, 2003; Zhang and Zhou, 2005; Fukuhara et al, 2006; Ren et al, 2007). Studies have shown that organo-montmorillonite has a high affinity for organic pollutants (Li, 1997; Zhu et al, 1998; Han et al, 2001). The aim of this work is to investigate the feasibility of removing 17b-estradiol from aqueous solution by adsorption onto organo-montmorillonite.

Jan 1, 2008

By Tukkimies M

During the late-1980s crawler-mounted crusher units established their position in the aggregates industry. Between 1986 and 1994 about 700 units were delivered to customers all over the world for surface operations, mainly in Scandinavia and central Europe. The crawler-mounted units are popular among smaller crushing operators because they are versatile and easy to move between sites. In large quarries the greatest benefit is obtained by combining a primary crawler-mounted crusher unit with mobile belt conveyors which eliminates the need for costly haulage by dump truck. Savings of up to 40 per cent in production costs prior to secondary crushing have been achieved. Today the environmental aspect in quarrying is assuming ever greater importance. Besides being costly the dump trucks are also the major source of dust and exhaust fumes within a quarry. A complete face crushing system consisting of a crawler-mounted crusher unit and mobile belt conveyors can be electrically driven and can be equipped with dust encapsulation and dust collectors. A mobile crushing unit is not a new idea. From the mid-1950s onwards the mobile and self-propelled units have been built equipped with crawlers, tyres or walking mechanisms, with weights usually of 500-1000 t. Due to their massive size these unit are not mobile in the same way as the today's mobile units. It is not feasible to move them more than a few times a year unlike today's fully mobile units which are often relocated once an hour. This means that the massive units can not continuously follow the production face and their loading always requires a certain amount of haulage. Today the mining industry is facing new challenges. With low mineral prices and high labour costs, increasing productivity is essential for survival. New standards are also being set for the labour safety and the environment. Large research programs have been launched to meet these challenges. However, technology which can partly solve these problems already exist and is only waiting to be introduced into underground applications as well - the mobile crushing unit followed by belt conveying. As in surface operations the elimination of truck haulage also brings considerable savings in operating costs in underground mines and reduces the amount of dust and exhaust gases generated. An additional benefit especially in underground applications is improved safety. In an underground mine most accidents are caused by moving vehicles.

Jan 1, 1995

This report chronicles the historical development of longwall mining in the United States and speculates on future developments to the turn of the century. Five eras of technological development during the modern period are described and analyzed. These eras discuss the development of (1) mechanized extraction, (2) self advancing roof supports, (3) high capacity roof supports, (4) shield supports, and (5) system automation. Current trends are analyzed in terms of: longwall utilization, production capability, support capacity, face widths, and new technological developments. From these analyses, the future of longwall mining to the year 2000 is speculated. It is concluded that longwall mining will continue to grow in importance during the next decade and that the next major technological milestone will be the realization of a fully automated longwall mining system.

Jan 1, 1992

By P Radulovic, W Y. Lui

The Mount Isa Mines (MIM) copper concentrator at Mount Isa processes both chalcopyrite ore from the MIM underground mine and rotary holding furnace (RHF) slag from the MIM copper smelter. There have been numerous changes to the processing practices since commissioning this concentrator in 1973. Current management of the concentrator extends from grinding and flotation to concentrate handling (thickening and filtration) and tailings disposal (fill plants, tailings thickeners and process water systems).Predominant mill feed through the concentrator is chalcopyrite ore. RHF slag is processed when concentrator production exceeds mined ore production. The chalcopyrite circuit has two stages of grinding in parallel lines (Line 1 and Line 2). Each line has parallel preflotation and rougher banks, combining into a common scavenger/retreat circuit (including regrinding) and common cleaner circuit. RHF slag may be milled in parallel with chalcopyrite, utilising Line 2 flotation roughers and a Jameson cell cleaner. All final concentrate produced is combined and pumped to the concentrate handling plant. The concentrate is thickened, pre-fluxed and filtered in hyperbaric disc filters. Fluxing specification is set by the copper smelter, and filtered product transferred via conveyor belt to the smelter concentrate storage facility.Wet fill and paste fill plants utilise flotation final tailings as hydraulic or cemented hydraulic fill for stopes underground. Cement ratios and fill plant utilisation are varied depending on underground stope fill requirements. Tailings from the adjacent lead-zinc concentrator are also processed at wet fill. All tailings that are not utilised for backfill are pumped via wet fill to three parallel tailings thickeners. Thickener underflows are gravity fed to the tailings dams with thickener overflows recycled for site process water use. In addition to summarising historical operations, this paper will provide a detailed outline of more recent changes in the concentrator flotation circuit, equipment upgrades, reagent optimisation as well as product and process optimisation at the final concentrate handling and fill plants.CITATION:Lui, W Y and Radulovic, P, 2013. Mount Isa Mines copper concentrator - An insight into current and historical practice, in Proceedings MetPlant 2013 , pp 553-574 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By J Player

Big Bell Mine started experiencing relatively large mining related seismic events, and accompanying rockbursts, from February 1999. Twelve rockbursts damaged access development from February 1999 to June 2000, with severe damage extending for up to 100 m along footwall drives. Five seismic events associated with the rockbursts were recorded by the AGSO, measuring 1.9, 2.2, 1.7, 2.4 and 2.2 on the Richter scale. These events affected 485 and 460 footwall drives in August and November 1999 and 535 footwall drive in June 2000 (drive level nomenclature is equivalent to the depth below surface and RL). After the third event (July 1999) it was apparent that the seismicity was not a once-off phenomenon. This (sudden) onset of seismicity required management to implement a series of precautionary measures:to ensure the safety of the workforce, to maintain continuity of production, and to reduce rockburst damage rehabilitation. The measures included extended re-entry periods and exclusion zones in high-risk areas, improved rockburst resistant support systems in areas prone to damaging seismic activity and improved support systems in areas prone to shakedown damage. A full-scale minewide ISS seismic system was ordered in October 1999 and commissioned in February 2000. A portable eight-channel CSIR-Miningtek system was installed at short notice as an interim measure in August 1999. This CSIR system covered the northern producing stopes, where the majority of the rockbursts had occurred. The objective of the seismic monitoring was to monitor relative activity and to determine trends with regards to time and location. MAP3D numerical modelling was used to investigate the relationship between seismicity and various combinations of stress components to assess the relative seismic risk in both current and proposed working areas. This information is used to determine where and at what stage in the mining cycle the rockburst resistant support is required. Analysis of the seismicity has determined two distinct modes of seismicity û small-scale localised, high frequency events in high stress areas and larger events related to shear along previously intact foliation surfaces. This paper includes a summary of the seismic history, seismic data analysis, support system design, mine design adjustments and management action to minimise the effects of seismic activity at Big Bell Mine.

Jan 1, 2000

South Africa is a semi arid, water scarce country that has undergone recent major political and social transformation. This transformation has ensured that water management has become a primary environmental concern in the South African mining industry, raising the status of water from an ancillary service to a fundamental factor in mine planning. The coal mining industry has been involved in the development of integrated catchment management plans since the late-1980s when a series of initiatives commenced in catchments where collieries operated. The plans focused attention on water supply and water demand management, the equitable access to water supplies, and intersectoral approaches to decision making, before the promulgation of new legislative and policy frameworks. Development of an integrated watershed management plan for the Olifants River basin, located in the Mpumalanga province, commenced in 1990. The Olifants River is an international river basin of 54 570 square kilometres and shared by South Africa and Mozambique. The upper watershed, locally called the Witbank Dam catchment, will be the focus of this paper. It has an area of 3400 square kilometres and is the major coal mining, power generating, and maize-growing region of the country. The processes embodied in the integrated watershed management plan had no formal guidelines but rather developed in an ongoing fashion over time. The plan commenced with a situation analysis involving the major stakeholders that identified principal technical shortfalls. These shortfalls were investigated under the guidance of multisectoral committees. The Olifants River Forum was started to extend awareness of the initiatives on an informal level throughout the whole watershed. The results of the investigations enabled water quality guidelines to be established for the upper catchment. To achieve the guideline levels additional initiatives were developed including a scheme to manage mine water discharges into the river system, the development of a standard four-step water management process, investigation and development of innovative mine water treatment processes, specifically sulfate reduction technologies, the use of gypsiferous mine water for irrigation, river and dam hydrological models, groundwater models and biomonitoring. Significant outcomes from the process have been achieved including the improvement in water quality in the Witbank Dam catchment. Equally significant have been the development of partnerships between businesses and between businesses and the community specifically in the use of mine water for irrigation. The plan realised a number of requirements for success including, the development of trust, openness and transparency with information, the essential need for consultation and negotiation and the involvement of third parties to validate information. The future still holds the potential for disputes between upstream and downstream water users but understanding, transparency and accountability between all players have, and will in future, enable the matching of the increasing demands on a scarce water resource to the needs of all.

Jan 1, 2003

By Howell M. W

The purpose of this paper is to outline the main points in the construction of the various types of wire ropes more commonly used for winding in Australia; and the maintenance of the ropes, and cage and skip safety gear as practised at the South mine, Broken Hill.It should be mentioned that both of the shafts at present in use are dry, and both downcast with or without the assistance of the two exhaust fans normally in use: Night shift and week.-end overtime are practicaly non-existent.Thus, during night shift, the cages in No. 7 shaft are landed on the chairs at the surface, providing efficient covers for the· shaft, and allowing the maximum amount of rope to be wound on to the drums. This also applies to the cages of both No. 7 and No. 4 shafts during the week-ends.These factors, combined with electric winding and skip haulage, are calculated to obtain the best use of the ropes when properly attended.WINDING ROPES-TYPE AND CONSTRUCTIONThese ropes may be divided into four main types which will include the more commonly used constructions(a) One-size strand.(b) Warrington strand.(c) Flattened strand.(d) Locked coil.1. One-size strand as the name implies, is a rope the strands of which are constructed 9f wire of the one size.Usually the strands are of 7, 19 or 37 wires.

Jan 1, 1940

The West Fork project is located in Reynolds County, Missouri, in the mineralized zone referred to as the Viburnum Trend. The West Fork orebody has a calculated ore re- serve of 13 600 000 tonne (15 000 000 st) con- taining 5.5 per cent lead, 1.2 per cent zinc, and recoverable values of copper and silver. A total of 64 600 tonne (71 200 st) of lead concentrate and 11 300 tonne (12 500 st) of zinc concentrate will be produced annually. The mill was designed to operate at an average capacity of 3450 tonne/day (3800 st/day), based on a 95 per cent availability factor. The mill will operate 24 hours a day, 5 days a week, with maintenance performed, as needed, on weekends. The mine will operate on an identical schedule; but the underground, pri- mary crushing will operate on a six hour/shift, three shift/day schedule. The 1.07m x 1.22m (42in x 48in) jaw crusher will produce a minus 20cm (8 in) material at an average rate of 191 tonne/h (211 st/h). The jaw crusher has almost twice the throughput capacity required, but the decision to install that size of crusher was based on the need to handle over sized rock in the ore.The coarse crushed ore will discharge into a 180 tonne (200 st) skip pocket, which will allow up to a one hour surge capacity prior to hoisting. Hoisted ore will discharge into a 900 tonne (1000 st) storage bin located adjacent to the headframe. The skip pocket and coarse ore silo comprise the total ore storage capacity. The concept of having no intermediate fine ore storage between the secondary crushing and grinding sections was borrowed from the Brushy Creek Mill of St. Joe Minerals, which operates adjacent to the West Fork property. Integration of the secondary crushing and grinding circuits has worked ' successfully for years at the Brushy Creek Mill. The most obvious advantage to eliminating the intermediate fine ore storage is'capital expen- diture savings. The capital expenditure savings include the cost of silos, feeders, and the cost of additional conveyor length and eleva- tion. Savings in operating costs will also be gained, particularly in reduced maintenance costs. Other factors which influenced the decision to eliminate fine ore storage were the simplicity of the secondary crushing sec- tion and the limited area available for con struction of the facility

Jan 1, 1978

Thank you and good morning. I am delighted to be here and to see so many of my colleagues and competitors. The general topic of this week's conference - World's Best Practice in Mining and Processing - suggests a focus on mining and processing. I am somewhat of a `jack of all trades and a master of none'. But I'm not even a jack when it comes to mining and processing technology and practices, and so I will leave those topics to speakers better 'qualified than I. Instead, what I would like to do is give you my thoughts on the best management practices of mining. You see, the times are changing for the mining business. There is great uncertainty in our industry. Anyone who received their education in an English-speaking school probably remembers the famous poem `Invictus' by William Ernest Henley. The two most famous lines from that poem are, if you remember, `I am the master of my fate; I am the captain of my soul'. The fact of the matter is that the metals industry, including the copper industry, is not the master of its fate. To a great extent we're at the mercy of forces over which we have little control, such as the world economy or political situations in individual countries. The copper industry is like a surfer at Manly - we can't influence where the wave is going; all we can do is stay in front of the curl and on our board. Historically, discovering, developing and processing ore reserves were the primary facets of our capital intensive business. To stay competitive today, we must invest equally in intellectual capital - our employees - in order to succeed in the face of economic, regulatory and political challenges and global competition (Schonberger, 1986). Everyone seems to have a different theory about being competitive. A lot of people use sports analogies when talking about competition. Others, like American businessman and former US presidential wanna-be Ross Perot, take a more interesting approach. In Mr Perot's hypothetical corporation, competition is a lot like having a snake in a factory. If someone sees a snake, the first thing they do is create a committee on snakes. Then, the committee on snakes meets and discusses the problem for a couple of years. The most likely course of action is nothing. Everyone figures that the snake hasn't bitten anyone yet, so they just let him crawl around the factory floor. Perhaps a vice president of serpentine affairs is appointed to continue watching the snake - making sure it doesn't grow. Ross Perot sees it a little differently. In his corporate world, business needs to build an environment where the first guy who sees the snake kills it. Of course in our industry, we better make sure the snake isn't on an Endangered Species List before we go after it! I am not going to talk about competition and competitive forces in terms of sports or snakes, but I would like to share some thoughts with you about how the mining industry can better utilise competitive thinking to get ahead and stay there. You may be wondering how an executive from a 160-year-old company could know much about competitive spirit, but the founding ancestors of Phelps Dodge were wizards at identifying

Jan 1, 1995

By J Rowland, B Belle, M Webber

The Australian underground coal industry has experienced substantial improvements in longwall productivity and, as such, the methods of providing a safe and productive mine environment have needed to evolve and develop. Whilst the primary method of controlling atmospheric conditions is by airflow it has become impracticable or impossible for the majority of Australian longwall mines to contend with all environmental hazards with primary ventilation alone.If the ventilation circuit cannot provide a safe and productive mine environment at an acceptable cost and circuit duty then supplementary controls are required. Examples include pre-gas drainage, post-gas drainage, gas utilisation, refrigeration and innovative dust control systems. Of the 21 longwall operations surveyed in Australia, there were 13 in New South Wales and eight in Queensland.This study represents a timely opportunity for the industry to examine the primary and supplementary ventilation systems implemented in Australian longwall mines and to discuss how to equip the industry to successfully face the future of underground longwall ventilation management in Australia.CITATION:Webber, M, Belle, B and Rowland, J, 2017. Australian longwall ventilation systems, in Proceedings Australian Mine Vent Conference 2017, pp 301–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By M D. Rosengren, G Gregor, M F. Young

Over the last 15 years the silver/lead/zinc ore treated at Mount Isa became increasingly complex and lower grade. Metal recoveries dropped dramatically, causing a serious decline in profitability. The ætraditionalÆ response of increasing tonnage to reduce unit cost was unsuccessful, since the additional tonnage was even lower quality ore. A major technical and capital program in the 1990s restored metallurgical performance, but business return was still too low and ore quality continued to decline. In 1996 a new, holistic approach integrated the steps of geology, mining, concentrating, smelting, and refining. Previous assumptions about æfixedÆ and æmarginalÆ costs in mining and processing were shown to be wrong. Detailed analysis showed that some ore sources were reducing profit. This led to a fundamental redesign and downsizing of both Mount Isa and Hilton mines. The result was dramatic increases in head grades, metallurgical performance and plant stability without any capital expenditure. The business is now smaller, but more profitable.

Jan 1, 1998

By G J. Butler

Since 2005 BHP Billiton Iron Ore has been working with the consulting company Runge to implement the software XPAC Advanced Destination Scheduler (ADS) in life-of-mine studies. The Mt Whaleback mine, being the single biggest open cut iron ore mine in the world, presents some special challenges in scheduling. The biggest challenge has been the slow run time and difficulty in targeting all ore and waste requirements. The high waste to ore strip ratio means that much of the cost of mining is tied up in waste dumping. It is therefore very important to schedule waste efficiently. At Mt Whaleback there is an additional challenge of managing two types of waste: inert and environmentally sensitive pyritic material. This paper shows how the XPAC destination scheduler is configured to achieve efficient and repeatable waste scheduling results at the Mt Whaleback mine. It also discusses proposed improvements to the process. The overall ore and waste schedule is configured to target mining parameters, crusher feed and grades. The schedule is run in two stages. The first stage is ore mining. The waste that needs to be mined is locked in a sequence. The second stage is the waste scheduling. The waste destination scheduler uses three inputs: source waste parcels locked in a sequence, a haul road and a waste dump block model. The process involves setting some rules for dump progression and haul path selection. These can be validated. The schedule is then run to target the shortest travel time. The results of scheduling are graphical and numeric and can be transferred into many different formats for reporting. The graphical result shows face positions in time that can be used for detailed dump design. The numeric results are used to estimate truck fleet size, fuel consumption, labour and equipment financials. The process has been successful in reducing the project time line, increasing the ability to do more scenarios and increasing schedule accuracy, transferability and repeatability.

Jan 1, 2007

By J J. Jiang, M Reimnitz

The Kalgoorlie Consolidated Gold Mines (KCGM) Fimiston Open Pit is mining through a dense network of disused level workings and open stopes of greatly varying sizes. The condition of the stope crowns and remnants is often unknown, and ultimately these structures become a significant proportion of the production floor and pit walls. Significant seismic events and occasionally rock bursts often occur in the underground workings. Seismicity is becoming an issue to the viability of the KCGM Fimiston operations. KCGM needs to take a leading role in understanding mine-induced and regional seismicity. The seismic system trials were initiated in the Fimiston Open Pit in 1996 using the ISS system. The initial system included two triaxial geophone arrays and two triaxial accelerometer arrays installed into two boreholes. The main objectives of the trial were to investigate the suitability of the two types of sensors and the detectability of seismicity in the pit. The trial was regarded as a success and the system has been expanded and improved. The current system consists of 12 triaxial geophone and accelerometer arrays and nine uniaxial geophones. The 12 triaxial arrays are installed in nine boreholes drilled from the pit and the nine uniaxial geophones are installed from underground level workings about 660 m below the original surface elevation. The system is designed to provide seismicity coverage for the entire pit area that is about 2.7 kilometres long, 1.5 kilometres wide and about 300 metres deep. The accuracy of the source location has always been a challenge due to the existence of the dense concentration of stopes and lack of the sensors. It is uncommon to have direct ray path for the seismic waves to propagate to the sensors across the strike, hence sensors have been located along strike and under the old workings. This paper discusses some of the challenges associated with seismic monitoring near mine remnants and seismically active faults. The results of the seismic monitoring are presented, and contrasted to results of three dimensional boundary element numerical modelling. The impact of the seismicity upon pit slope stability is briefly discussed.

Jan 1, 2003

While specific definitions of the main categories of mineral reserves and mineral resources are becoming well established through the efforts of the Australasian Joint Ore Reserves Committee (JORC) and the Combined Reserves International Reporting Standards Committee (CRIRSCO), there has been perhaps less attention paid to the standardisation of language used in the definition and reporting of Mineral Exploration Results and a clear understanding of the transition to Inferred Mineral Resources. This is an area of significant importance to small and medium sized enterprises in the mineral exploration sector as it represents in many cases the only tangible information by which the reader or potential investor can evaluate the future potential of such enterprises. By its very nature information in the Mineral Exploration Results category is incomplete, and frequently complex, and it is open to a broad range of interpretation by readers of various competency levels and disciplines. Many will have a short-term speculative view rather than a long-term perspective, with others out deliberately to misrepresent the information, and as such it can have an enormous impact on investment decisions if the risks associated with this information being reported are not fully understood. Authors of reports on Mineral Exploration Results, who may be Competent Persons or company directors, have to put themselves in the shoes of the reader of the report, second-guessing if you like what the reader will understand by a report, which in many cases will be of a highly technical nature. This raises reporting dilemmas and questions that require to be understood and addressed. Looking at reports on Mineral Exploration Results from the other side, readers have a degree of responsibility as well, particularly if they engage in an advisory or communications role. The tendency of commentators, journalists, analysts, and bulletin board posters to over-exaggerate the significance of a particular exploration result is all too familiar. Questions arise here as well about whether there should be more regulatory supervision and control exercised over those who use this information, all of whom greatly influence investment decisions, and many of whom have no idea there is a Reporting Code, far less an understanding of it. Examples are given and questions raised to illustrate the dilemmas surrounding the reporting of Mineral Exploration Results. In order to retain credibility with markets it is incumbent on companies to be transparent, not to be selective and to report all material information. On the other hand, information has to be taken and read in its proper context in order to avoid fuelling dramatic and unjustified company share price escalation. Timing of course is another factor that can affect the market price of shares, which may be beyond the control of those making the reports. Emotive and imprecise language, however, when reporting Mineral Exploration Results, coupled by speculation, can trigger damaging short runs on shares and destroy credibility where formerly there was long-term promise. The paper will review how Mineral Exploration Results are dealt with in various jurisdictions, and conclude that there has to be a balance between prescription and the tempering of undue optimism on the one hand, and the entrepreneurial spirit, which the industry needs, on the other.

Jan 1, 2002

The link between exploration success and new ideas from research and development (R&D), although often assumed, is rarely well explained or well illustrated. One issue is understanding the role of innovative ideas in the exploration process, and another is determining the relative contributing factors to an exploration success. A useful measure of gold exploration success over an extended time period and geographic area is discovery rate (θ): Discovery rate θ = gold discovered/exploration expenditure (usefully expressed as tonnes of gold per $1 million). The total gold discovered is strongly leveraged to discovery rate, as any increase in θ typically has a positive effect on exploration expenditure. Hence, improving the discovery rate is a key driver for a sustainable mineral industry, especially for gold. There are very few ways to influence θ beyond innovative R&D ideas and breakthroughs, and well-motivated and trained staff. The Australian gold industry has experienced exceptional exploration success with 9956 tonnes of gold discovered from 1979 to 2003, inclusive. This equates to: Discovery rate θ = 0.9 t/A$1 M Two-thirds of this gold has been found in the Yilgarn craton of Western Australia (6265 tonnes Au). Without this exploration success, there would have been no platform on which to build the current gold industry and to take advantage of elevated gold prices and advances in mining and processing. Several causes of the Western Australian gold success have been proposed, and more than one may be correct. Gold price, and mining and processing advances have all had influence; but exploration success and discovery of gold were essential to add to the miniscule resource base of 1979. A comparison of the exploration methods used to search for gold in the Yilgarn craton in 1979, and 1990, highlights a small number of breakthrough ideas introduced to the industry during the 1980s, and in most cases emanating directly from local R&D. By the 1990s, these ideas were being used in most gold exploration programs in the Yilgarn craton, and are still used today. These six breakthroughs are: epigenetic timing of gold deposit formation (ie after formation of rock sequence), chemical and mechanical role of host rocks, relevance of carbonate alteration haloes, gold dispersion in the regolith, optimal sampling media, and appreciation of landforms in exploration program design. Interestingly, gold exploration science in Western Australia entered the 1980s period without rigid paradigms in place regarding gold deposit formation; there was a balance between descriptive and genetic models, there was scope to research gold deposits from microscopic to global scales and there were highly effective industry research uptake processes in place: it is suggested here that these favourable conditions contributed to the exploration success and industry growth.

Jan 1, 2007