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By R Carreau

The results of a detailed acid rock drainage (ARD) prediction program were used to revise the waste rock segregation criteria at the Restigouche open pit mine. Waste rock at the site was predominately derived from altered volcanic rocks that hosted a massive sulfide lead/zinc orebody. The program assessed the five years of drainage chemistry from both the potentially acid generating and the non-acid generating waste rock storage facilities in addition to laboratory-based kinetic test results. Material-specific leaching characteristics including relative metal-release rates and neutralisation potential depletion rates were determined from 12 laboratory-based kinetic tests. Solid-phase analyses indicated that, although pyrite was typically the most abundant sulfide mineral in the waste rock, its abundance varied significantly as documented by total sulfur contents ranging from 4.0 per cent. Kinetic test results were used to establish revised waste rock segregation criteria based on total sulfur content and neutralisation potential. The revised criteria maintain that waste material with a total sulfur content 4.0 per cent as potentially acid generating. When present in sufficient quantities, ankerite provided an effective source of neutralisation potential for the range of observed sulfide oxidation rates. Kinetic testing documented that up to 6 kg CaCO3/t was ineffective at neutralising acidity in samples that contained >4 per cent S. The carbonate molar ratio measured from the humidity cells was adjusted to reflect the stoichiometry of the ankerite and applied as an NP/AP criteria for waste rock containing 0.1 <S per cent <4.0.

Jan 1, 2003

By K Hortin

Kidd Creek mine in north western Ontario is developing phase 1 of the deep mine project for mining between 2100 m and 3100 m below surface. Heat problems were experienced during the 2003 summer in working places about 2300 m below surface. At the time the mine had a æcold stopeÆ for cooling the air supplied to the mine below 1500 m from surface. The æcold stopeÆ is where during winter, ice is created in both the open pit and its connecting airways to the mine and used to cool air in summer. The operation and limitations of the existing cold stope were evaluated and led to the requirement for additional mechanical cooling to be available for the summer of 2004. The first stage of a surface refrigeration plant providing 7.5 MWR of cooling was approved, the compressor set was ordered in early January 2004 and the plant commissioned six months later in early July 2004. Based on the current modifications to the mining plan, further plant expansions are required in 2006 and 2009 leading to a total of 19 MWR of mechanical refrigeration and 8.5 MWR equivalent from the extended cold stope. The refrigeration system is described with emphasis on the specific adaptations necessary to suit Canadian conditions. Additional investigations were; using the refrigeration compressors in winter for heating and, extending the performance of either cold stopes or alternative ice storage systems. The winter use of refrigeration involve removing heat from the mine exhaust air to provide a cooling load and to use the hot water in the condensing circuit to heat the intake air and reduce reliance on mine air heating with natural gas. This paper follows on from an earlier one presented at the Seventh International Mine Ventilation Congress where the background and planning of the mine ventilation and cooling requirements were described for extending the mine at depth to 3100 m.

Jan 1, 2005

By A Winchester, D Grant

The massive 1100 Orebody in Mount IsaÆs X41 Copper Mine has been extracted over the last 40 years form north to south utilising sublevel open stoping methods.De velopment has continually stepped ahead of production to provide access to new primary stoping blocks. The remaining secondary pillars contain stopes with one, two or three fill mass exposures and were constrained by access requirements and stope extraction turnaround time.The remaining southern mining areas consist of large 40 m wide by 300 to 400 m long east-west transverse pillars that have been left to provide access for ventilation and service requirements. Three large transverse cross-cuts or transverse pillars û 4180 x/c, 4010 x/c and the Panel pillar now remain. The 4180 x/c was the last major transverse pillar to be successfully broken.This transverse pillar is being extracted in a retreating sequence, creating 3SLOS stopes due to the surrounding backfilled stopes.In recent years the extraction of the first, and most critical, stopes in the transverse pillars have resulted in large changes to the induced stress field. This paper describes the extraction of the 1.1 million tonne stope P418 in the 4180 x/c pillar.T echnical challenges that were faced and how they were overcome to allow for the successful extraction of the stope are described.Critical to the success of the P418 stope extraction were the rehabilitation methodology used; extraction strategy modifications to address deteriorating ground; mass firings with multiple directional changes; managing the exposure of backfill of variable strengths; and geotechnical monitoring prior to, during and after extraction.

Jan 1, 2005

City Resources Limited selected Vanuatu as a target area for epithermal gold mineralization because of its relatively unexplored character and its location on the southwest Pacific rim. During 1985 a systematic program of reconnaissance prospecting was completed on six islands within the Vanuatu group, using a helicopter and a specially designed exploration support vessel with on-board assay laboratory. Within a period of 4 months, reconnaissance prospecting of all six islands was completed, two previously unknown epithermal gold provinces had been discovered, and six major prospects warranting detailed exploration had been identified. Factors which contributed to the success of the program include (i) a flexible management approach, (ii) the mobility and access provided by the support vessel/helicopter combination, (iii) rapid assay turn-around, and (iv) adherence to basic prospecting techniques. The relative merits of various sampling media are discussed.

Jan 1, 1987

By S Sabanov

Supplementary sampling of particulate mass concentration, the number concentration and the average particle diameter of nanoparticles using a TSI Dust-Trak DRX Aerosol Monitor, Naneos Partector 2 has been conducted. The aim of this study was to evaluate suitability of the instrument for long-term monitoring of diesel particulate matter (DPM) at conditions of polymetallic mines. Sampling was conducted in an area of the active ore heading, requiring the use of a diesel-powered face haul-age loader R1700 and a mine truck Caterpillar AD-45. The sampling was done for 126 minutes at a distance of 30 metres from the mine face. Results of this field work can be used to expand the sampling program to other mines. Expected outcomes of this study are to develop costeffective DPM control strategies, improve mine ventilation, and protect mineworkers’ health.

Oct 12, 2022

By Low Russell

Mark Westfield, writing in The Australian on 16 May 1994 stated: The role of the independent expert is crucial to Australia's investment system. When it falls down, there can be very dramatic consequences. The scope of these consequences was dramatically illustrated in the decision of Rogers J. at first instance in Cambridge Credit Corporation v. Hutcheson (1983) 8 ACLR 123 when the auditors of the failed company were found liable for breach of contract and faced a damages award of $145 million, well in excess of their insurance cover. No comfort should be sought in the fact that this decision was overturned on appeal, for the result of the appeal rested on whether there had been a causal connection between the breach of contract which had occurred and the loss suffered, rather than on the fundamental principle of auditors' liability. Thus: Those who prepare experts' reports in company cases carry a heavy moral responsibility, whatever their legal duties may be... Unless high standards are observed by those who prepare these reports, there is a danger that systems established for the protection of the investing public will, in fact, operate to their detriment through reliance placed on those reports and on the reputations of those who furnish them. In lending his name, the expert will often, as in this case, be lending a name to conjure With.

Jan 1, 1995

By M Campbell, A Jeffcoate, J-C Vannay, B Perriaux

Phyllite waste rock at the Simandou Pic de Fon and Oueleba Iron Ore deposits (Guinea, West Africa) variably weather to form clay-rich rocks. This weathering modifies the mineralogical, geochemical and mechanical properties of the phyllites. Final pit walls will largely be formed in phyllite, so it is critical that the slope design takes account of the distribution and variability of weathering within this material. Phyllite intact material strength has been correlated with geochemistry (ie mineralogy) facilitating the establishment of domains of intact rock strength (IRS). In order to calibrate this geochemically-based strength model, core from diamond drilling (DD), comprising a variety of phyllite material types (from soft clay to moderate strength rock), was geotechnically logged to assess intact strength; further validation was achieved by uniaxial compression (UCS) testing and point load tests (PLT). The correlation between geochemistry and strength offers a potentially powerful tool for differentiating basic mechanical properties of the rock mass, especially at Simandou where a significant proportion of the resource drilling is done by reverse circulation (RC). Unlike DD, reliable measurements of material strength from RC samples can prove difficult, especially in clay-rich material. Therefore, gaining information from routine geochemical assay results, independent of the sampleÆs physical integrity, is a valuable and cost-effective source of reliable empirical data. Data acquired using this approach provides an opportunity to develop strength domains, which are integrated into mine planning block models. In combination with other geotechnical characteristics, this can be a valuable input to the development of geotechnical models. This technique has allowed spatially representative rock strength data to be derived and offers the potential for optimising pit slope angles in areas where hitherto conservative design criteria had been assumed.CITATION:Jeffcoate, A, Campbell, M, Vannay, J-C and Perriaux, B, 2013. Modelling intact rock strength of clay-rich rocks with geochemistry at the Simandou iron ore deposit, Guinea, West Africa, in Proceedings Iron Ore 2013 , pp 193-202 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By A Hewitt

Portland cement is the chief binding ingredient in mine backfill. In the presence of water, the chemical compounds within portland cement hydrate causing hardening and strength gain. During hydration, heat is generated. In certain cases, hydration heat may be produced significantly faster than it can be dissipated, which can create high temperatures in the underground environment. This paper presents the results of a series of investigations aimed at quantifying the heat generated by cemented backfill during hydration. Scaled stope models, instrumented with thermistors, were used in the investigation. Heat transfer to the hanging wall, orebody, footwall and cross-cut and production drifts was assessed during the backfill curing process and relationships between cement content, cure time, and heat generation were developed. The results of this work will assist mine operators in predicting the heat generated by cemented backfill and provide the necessary information to implement effective engineering control of heat in the underground environment.

Jan 1, 2005

By J Durbin

To effectively plan for closure, we must have an end-point in mind. To undertake meaningful rehabilitation, a post-mine land use (or uses) must be known. However, it is becoming more apparent that the end-point or “goal-posts” are shifting - and may continue to do so throughout the life of a mine. As well as being safe, stable and not causing environmental harm, post-mine land uses should always be sustainable, achievable within the given land capability, and they should involve stakeholders in their design and development.The majority of mines in Australia, and around the World, were historically expected to return disturbed land to either native ecosystem or agriculture/forestry practices. However, examples of highly successful final land uses suggest that today’s focus on closure includes not only minimising future liability and impact but also – and importantly – a move towards the creation of economic opportunity (Murphy and Heyes, 2016).CITATION:Durbin, J, 2018. Planning for (not so) final land use, in Proceedings Life-of-Mine 2018, pp 110–112 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

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

By B Siddall, A Gunstone

The use of a partial secondary crushing circuit provides a flexible way to optimise existing SAG comminution circuits limited by rock competency or enables optimal processing of an ore through second hand equipment not specifically selected for that ore. This paper details the process involved in designing a partial secondary crushing circuit using the recent installation at Mt Rawdon Gold Mine in Queensland as an example.

Jan 1, 2004

MIM Holdings Limited (MIM) committed to a long-term future in copper in the Carpentaria Mineral Province in 1996 with the development of the Enterprise and Ernest Henry mines, and an upgrade of MIMsÆ copper smelter in Mount Isa, and copper refinery in Townsville. The upgrade of the copper smelter will enable the smelter to produce 250 000 tpa of copper with a single primary smelting unit, the copper Isasmelt furnace installed in 1992. The copper Isasmelt furnace currently smelts concentrate containing 145 000 tpa copper. To reduce the risk associated with the copper smelter upgrade, and shorten the ramp up time of the upgraded smelter, two high-rate trials were undertaken in 1997 to demonstrate that the copper Isasmelt furnace could, with an additional 525 tpd of tonnage oxygen, treat concentrates containing 250 000 tpa copper. During the trials the concentrate feed rate to the Isasmelt furnace was increased from its average rate of 100 tph of concentrate to 150 tph of concentrate. The increase in the capacity of the furnace was achieved by: supplementing the installed tonnage oxygen capacity of 595 tpd with an additional 300 tpd supply; reducing variability in the furnace feed rate from ¦25 per cent to less than ¦5 per cent; and reducing tramp air. The Isasmelt furnace smelted concentrate at a rate of 140 to 150 tph for four hours 25 minutes during Trial 1, and at a rate of 150 tph of concentrate for five hours and 30 minutes during Trial 2. The oxygen utilisation was 100 per cent during the trials with the process remaining under control. As a result of the development work for the trials the average treatment rate of the furnace under normal conditions increased by ten per cent.

Jan 1, 1998

By L M. Zhang, T H. Xu, J Zhao

Blasting is one of the most commonly used strategies for excavation in civil and mining engineering. Yet blasting can also bring along such undesirable effects as ground vibrations and soil disturbance. Numerical analysis is a powerful tool for estimating the effects of blasting and improving blasting design. In this research, a constitutive model for sand is proposed for the numerical analysis of blast-induced ground motions and wave propagation in soil mass. In the model, three model surfaces, ie the critical surface, the dilatancy surface and the bounding surface, are defined following the bounding surface hypoplasticity framework. The strain rate is included explicitly into the model formulations so that the proposed model is valid under high strain rate loadings caused by blast-induced vibrations. The performance of the proposed model is validated by the simulation of drained triaxial compression tests conducted on a crushed coral sand under different strain rates.CITATION:Xu, T H, Zhang, L M and Zhao, J, 2014. A bounding surface model for sand subjected to blast-induced vibrations, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 201–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By S Tierney, D Cumming-Potvin, I Thin, Y Potvin, D Grant

The preliminary modifying factors for future stope design in the Southern Mine Area of Olympic Dam consisted of only a single, arbitrary value of Equivalent Linear Overbreak/Sloughing (ELOS). In order to improve this, a study was conducted which developed a more comprehensive methodology for assigning ELOS, Equivalent Linear Lost Ore (ELLO) and Equivalent Linear Fill Overbreak (ELFO) to individual stope faces based on geotechnical and mining parameters. The approach used was to look at the simple cases, which were classed as vertical stope walls in good ground (RQD 80-100%), divided into wall orientations (North, South, East, West). The stope walls were also split based on the blasting practice used (toeing, parallel or a combination of the two). The expected ELOS and ELLO from these ‘base cases’ are then modified by parameters which have historically been found to affect stope performance (Hydraulic Radius and Q’). The size of the effect found in the historical data determines the ELOS / ELLO applied. The methodology was summarised in an easy to use flow chart and was applied to all of the proposed stope shapes for the Southern Mine Area and summarised per mining block. This allowed each iteration of the mine plan to be assessed in terms of overbreak (both rock and vertical fill exposures) and underbreak.

Mar 15, 2021

British Coal's Selby Complex is the newest producing mine in the United Kingdom. The reasons behind its origins, planning and design are explained. Some detail is given of equipment used, with the emphasis being placed on the unique features of its layout. The entire project has been planned and constructed over many years and the design has consequently changed, principally in response to the geology of the coalfield and improving technology. In spite of many totally unexpected difficulties, the mine, which is not yet in full production, has the highest productivity in the United Kingdom.

Jan 1, 1991

The value of Australia's education services exports increased to over $15 billion dollars in 2009, placing education as the third overall export earner behind coal and iron ore; however there are concerns over the impact of emerging policies on the future of both the industry and the provision of mining education. Policies have impacts on the growing number of international rankings (or league tables) of mining jurisdictions and universities. A high position in such rankings might be used as a measure of perceived quality with benefit to those at the top and to the detriment to those lower down.    Top performing companies in the relatively new domain of sustainability have been shown to achieve better financial performance than their industry competitors, assisting them in attracting top quality committed staff, hence positioning themselves well for the future. The world's mining companies, jurisdictions and universities are now ranked with results in the public domain. It is argued as to the validity of the data or perceptions used in such rankings, but there is no doubt they are influential in determining the flow of dollars around the globe. By investing your pension fund assets in the shares of the top performing companies, by placing your exploration dollars in a country at the top of such a list of attractive jurisdictions, attending or recruiting from a University at the top of the rankings - risk must surely be reduced?   While savings and risk reduction can undoubtedly result from the introduction of new technologies developed through appropriate R&D (the other core activity of a university), the maintenance of a very high level of exploration and production performance through dedicated highly skilled staff every hour of every day quietly improves financial performance, while avoiding safety, environmental and/or community incidents (ie protects the 'triple bottom line'). As always risk reduction comes down to enabling quality people to do a quality job - through the actions of such people we can sustain the global mining industry and secure our social license to operate. However, there is global concern over where the numbers of such people, including those with the recently required skills in sustainability, are going to come from.   This presentation will discuss some of the complexity and interactions involved in the development of such rankings, the dangers inherent in their simple acceptance and use, plus indicate some of the directions mining educators might take to sustain and increase the supply of quality graduates to the global mining industry. This is an ABSTRACT ONLY. No paper was prepared for this presentation.

Jun 1, 2010

By Bassett N

The Eneabba deposit, located 280 km north of Perth, Western Australia, and 30 km inland (Fig. 1) is one of the most recently developed deposits of mineral sands in the world. The area has been in production since 1974, while the Associated Minerals Consolidated Limited (AMA) operation commenced production in 1976. Total ore reserves of close to 400 million tonnes contain about 40 million tonnes of heavy minerals (proved and probable).

Jan 1, 1979

By Guo-Zheng J

This paper describes the risk management strategies adopted to control unstable slopes in the east open pit of the Daye iron ore mine. Extensive experience has been developed over the last 35 years in the management of pit wall instability resulting in the successful excavation and reinforcement of pit slopes over 350 m in height.

Jan 1, 1994

By I Levy

At our Monkland Mine at Gympie, we operate a deep, narrow vein gold mine using hand held equipment, rail mounted haulage and narrow shafts. This is in many respects the old-fashioned way and is well suited most of the orebody geometry exposed to-date. We have also commenced some long hole stoping and we use alimaks for some jobs. The heart of our particular mining style is the employment and retention of experienced miners with remuneration based on productivity. We do our planning/monitoring/supervision down to the level of daily individual productivity. In focussing on cycles per se, we have chosen not to talk about drill and blast cycles or cycles for mine development, stope preparation or drawdown and haulage. Instead we have stepped right back from the operation as presently run and have adopted a very broad view of the mining cycle. We will in this presentation intertwine the ebb and flow of, exploration, project sponsorship, development, production and cash returns to owners. The time line considered spans both history and predicted future.

Jan 1, 1998

By Brinkmann J. R

In the narrow stopes of South African gold mines, rockbreaking is carried out by drilling and blasting with safety fuse and igniter cord being used as the initiation system. The fuse/gniter cord system is used primarily because of its low cost, however several limitations of this method include: inaccurate delay time, unreliable firing, inflexible application to varied configurations, and the absence of dynamic interaction between holes. Alternative initiation systems that incorporate millisecond timing are being developed to overcome the limitations of fuse(tgniter cord systems. Current investigations by the Stoping Technology Division of the Chamber of Mines Research Organization (COMRO) into the effects of millisecond initiation are being conducted at a deep test site. Experimental blasts using various millisecond delays and the independent firing of holes with fuse/igniter cord are being studied in order to quantify the influence of delay time on the blasting process and to identify the best methods of applying millisecond initiation systems. The effect of design variables such as delay time, hole firing pattern, stemming, and panel layout are discussed. Blast results including throw distance and direction, muckpile profile and rock cleaning times are used in the discussion of different combinations of blasting variables.

Jan 1, 1990