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By F Clark, J T. Carswell

Ore definition for final stope planning is often a challenging prospect in underground (UG) gold mines which exhibit high geological and grade variability. Unlike the grade control (GC) scenario in an open pit (OP), the ability for the mining geologist to plan a sampling campaign which effectively characterises the underlying mineralisation is fraught with difficulty. UG sampling patterns are strongly clustered and typically not dense enough to characterise the spatial and statistical properties. Very commonly, sample volumes are not large enough to provide a reliable grade estimate of the surrounding rock. These factors critically affect our ability to accurately map out ore positions and estimate metal quantities.At Sunrise Dam, traditional UG sampling and modelling techniques have proven to be an unreliable strategy for successful stope planning and extraction. The problem was first observed during the final cut-back in the open pit for which the mineral resource model was constructed from UG diamond drilling. Open Pit grade control reconciliations were strongly positive for both tonnage and grade compared to the resource model. Underground workings missed significant quantities of ore which was laterally defined by open pit reverse circulation (RC) GC drilling. Upon examination it was realised that the cause of the problem was one of inadequate sample density and sample support, the implications of which potentially affected the entire UG mine.As part of a broader study into underground grade control procedures, detailed reconciliation of initial stope production from the GQ domain also pointed to inadequate sampling as a major constraint to effective grade control and reserve conversion.To overcome this deficiency, dense 115 mm wet RC grade control drilling and conditional simulation modelling has been successfully implemented with the intent to replicate the grade control process in the open pit. The increase in sample density and sample volume has proven to be a very effective tool for mapping out highly complex mineralisation. A marked improvement in stope definition, reserve conversion and Mine to Mill reconciliations has been demonstrated on the back of an innovative approach to UG grade control.CITATION:Clark, F and Carswell, J T, 2014. Using reverse circulation drilling to improve sampling in a complex underground gold operation – an innovative approach to underground grade control at the Sunrise Dam Mine, Western Australia, in Proceedings Ninth International Mining Geology Conference 2014 , pp 143–152 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By A Woodley, N C. Kunz

A mine site water balance is important for communicating information to interested stakeholders, for reporting on water performance and for anticipating and mitigating water-related risks through water use/demand forecasting. Gaining accuracy over the water balance is therefore crucial for sites to achieve best practice water management and to maintain their social license to operate. For sites that are located in high rainfall environments the water received to storage dams through run-off can represent a large proportion of the overall inputs to site; inaccuracies in these flows can therefore lead to inaccuracies in the overall site water balance.Hydrological models that estimate run-off flows are often incorporated into simulation models used for water use/demand forecasting. The Australian Water Balance Model (AWBM) is one example that has been widely applied in the Australian context. However, the calibration of AWBM in a mining context can be challenging. Through a detailed case study, we outline an approach that was used to calibrate and validate AWBM at a mine site. Commencing with a data set of monitored dam levels, a mass balance approach was used to generate an observed run-off sequence. By incorporating a portion of this observed data set into the calibration routine, we achieved a closer fit between the observed versus simulated data set compared with the base case. We conclude by highlighting opportunities for future research to improve the calibration fit through improving the quality of the input data set. This will ultimately lead to better models for run-off prediction and thereby improve the accuracy of mine site water balances.CITATION:Kunz, N C and Woodley, A, 2013. Improving the accuracy of mine site water balances through improved estimation of run-off volumes, in Proceedings Water in Mining 2013 , pp 267-272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

"Recognising that the mining industry is wedded to the break-even cut-off grade rather than a cut-off grade that optimises value, the author examines some perils and pitfalls in the use of break-even grades that lead to what the author calls ‘negatively geared ore reserves’.Negatively geared ore reserves occur when a portion of the ore reserves actually has a negative value and is effectively being subsidised by the more profitable portion of the ore reserves. This situation is generally difficult to detect with the level of information available to the public investor. The ore reserves can still be quite profitable in total, but now possess a level of risk that may not be appreciated.The risk profile (financial risk) of a negatively geared ore reserve is far greater than for a non-negatively geared ore reserve. Like a negatively geared investment property in a falling property market (for readers familiar with the Australian tax minimisation investment strategy), when the price of a commodity falls, a company that possesses a negatively geared ore reserve loses value at a magnified rate relative to a company that has a neutral or positively geared ore reserve. In the extreme case of a major commodity price reduction, as happened with the gold price in mid-2013, the negatively geared ore reserve can easily become negative value in total, not just in part.The negatively geared ore reserve is sometimes intentional – for instance in order to increase published ore reserve tonnages and meet the CEO’s key performance indicators – but is also often unintentional, resulting from various errors in the break-even calculation. Common errors in calculating a break-even grade include using fixed metallurgical recoveries, not including allowances for ideal laboratory versus real plant results, ignoring available operational data and using modal rather than mean parameter values in cost and performance calculations.This paper examines a common value distribution profile in many ore reserves and the effect of common break-even grade errors on this profile.CITATION:Poniewierski, J, 2016. Negatively geared ore reserves – a major peril of the break-even cut-off grade, in Proceedings Project Evaluation 2016, pp 236–247 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By J L. Kerr, J Beyer-Robson, S Vink

Driven by an increasing need for water conservation, coal mine operators in the upper Isaac River catchment have placed significant emphasis upon the reuse of water. This initiative led to an overall increase in the salinity of mine waters. The ionic composition of this water differs from local stream water in that concentrations of sulfate are higher than average stream concentrations by ten per cent, while concentrations of bicarbonate and calcium are lower. When this water is discharged into ephemeral streams in semi-arid environments there is potential for this increased salinity and altered ionic composition to impact upon the ecosystem processes mediated by micro-organisms in river sediments.We have measured nitrification, denitrification and methanogenesis rates in a series of lab experiments using sediments from Isaac River catchment streams and found that salinity affects these processes in different ways and to different degrees. Process rates were shown to differ seasonally between samples taken from the same location and habitat type and also between different habitat types at the same time and location. Both aerobic and anaerobic process rates were higher in surface sediments and it is likely that this activity is associated with surface biofilms. Furthermore, we have shown that the ecosystem processes we have measured are limited by the availability of carbon in the sediments.The management implications of these findings for mine releases into ephemeral streams will be discussed.CITATION:Kerr, J L, Vink, S and Beyer-Robson, J, 2013. The effects of increased salinity on microbially mediated ecosystem processes in ephemeral streams, in Proceedings Water in Mining 2013 , pp 121-134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By D J. Williams, C Zhang, F E. Herrera Cabrera

Farming on bauxite residue using screw propelled equipment (SPE) has been commonly practised to accelerate dewatering and as it promotes consolidation and enhances storage capacity. However, it is unclear when and how often farming should be conducted during the transition of bauxite residue from slurry to dry solids and how deep each slurry deposition should be. To address this issue, three desiccation tanks were established in the laboratory to investigate how much farming could enhance the desiccation and consolidation of tailings. The cuboid tanks, of 350 mm in height and 300 mm in width and length and with an opening on the top, were placed on load cells to monitor the water loss during desiccation and were instrumented with moisture and suction sensors designed and developed at the University of Queensland to measure the water content profile of the residue. The bauxite residue, composed of silt-size particles with low plasticity, was hydraulically deposited in the tanks as a slurry at 27% solid content, resulting in 100 mm depth of solid material settling. Evaporation was enhanced by placing two identical electrical fans above the tanks. Two phases were conducted. In the first phase, the two tanks were left untouched for evaluating non farmed conditions and for calibrating sensors, while in the second phase, three tanks were subjected to atemporal farming using purpose-built screw propelled equipment. The experiment was terminated when the residue was completely desiccated. This paper reports on the instrumented tank set-up and the results obtained to date.

Jul 1, 2021

By J Benn, V Kuznetsov, G Timms, A Spain

Earthen covers are now widely used in the mining industry to control the generation rate and/or release rate of low quality drainage from piles of sulfidic minewastes. Covers are usually designed to reduce the water infiltration rate and in some cases may also reduce the oxygen flux to the underlying sulfides. Engineered covers have only been used since the 1980s, however, and there is very little field data on their performance in the longer term. This lack of information has implications for the degree of confidence that can be placed on the predictions of the environmental impacts of sulfidic minewastes, for the acceptance of close-out criteria by regulatory authorities and for the financial liability of the mining industry. Covers were placed on sulfidic waste rock dumps at the abandoned Rum Jungle uranium mine during 1984 - 1985. These covers were designed to reduce the water infiltration to less than five per cent of incident rainfall by both water shedding and storage-release mechanisms. Regular monitoring by the Australian Nuclear Science and Technology Organisation (ANSTO) demonstrated that the covers performed better than the design criterion for around ten years, but infiltration rates have subsequently increased. There is a 66 per cent probability that the infiltration rate now exceeds five per cent of incident rainfall. The cover on the largest pile, WhiteÆs heap, was sampled in pits dug at eight locations. Sampling was carried out at the end of the monsoonal wet season and again at the end of the ædryÆ season. This, together with laboratory testing, enabled cover performance to be assessed against five criteria: design, construction, cover material characteristics, physico-chemical characteristics and biological characteristics. We are of the opinion that the design of the cover was suitable to achieve the objectives of stability, water shedding, storage-release, and provision of a substrate for vegetation growth. Over most of the surface of the heap, the construction of the covers, drains and erosion prevention structures was in accordance with design specifications. However, several small and localised bare patches on the upper surface of WhiteÆs heap coincide with a reduced cover thickness, which is likely to have been due to poor construction in those patches. The construction of covers on minewastes is dependent on an adequate source of material meeting design specifications. From our limited examination, it appears that there was shortage of material for each of the three zones û a lower impervious clay layer, the moisture storage-release layer and the upper erosion-resistant layer for vegetative growth. An indication of this was that the upper layers in some areas were observed to be thinner than specified. We are of the opinion that this shortage of suitable material has been responsible for some of the changes observed ten years after emplacement. Physical and geotechnical testing indicated that the cover materials no longer meet the original specifications. In particular, the permeability at the 8 locations was found to be greater than specified, by up to several orders of magnitude. The higher permeability may explain the higher observed rainfall infiltration and moisture content of the waste rock. This increased permeability appears to be due to a combination of biological and physical processes û galleries formed by termites and ants and an extensive system of shrinkage/desiccation cracks formed by the development of a polygonal blocky structure involving the entire lower clay layer. The desiccation cracks may fill with coarser illuviated materials and form a conduit through which roots access the underlying waste rock. Measurements were made of oxygen flux into the heap as cover layers were excavated in the pits. They indicated that the full cover currently reduces the oxygen flux to 20 - 23 per cent of that into bare waste and that this reduction seems to be proportional to the cover thickness. It was also found that the oxygen flux into the cover is about four times higher at the end of the dry season than at the end of the wet season and that the difference is due primarily to the difference in moisture content of the cover. Recommendations are made for the design and construction of covers.

Jan 1, 2003

By Z Li, Z Yan, T Htet, S Zhang

During the pyrometallurgical processes, a substantial quantity of high-temperature ironmaking and steelmaking slags, generated at temperatures ranging from 1400 to 1600°C, is wasted, as the heat contained in these slags is released into the environment during the tapping process without effective utilisation. On the other hand, a significant amount of energy is required to reheat the cold materials for the manufacturing of glass and mineral-wool, often necessitating the addition of high-silica materials to facilitate the production process. In this study, an innovative approach is presented to harness the heat present in molten metallurgical slags to directly produce new raw materials for glass and mineral-wool manufacturing while simultaneously reducing energy consumption and mitigating CO2 emissions. The theoretical amount of waste glass that can be effectively added in the process has been estimated via thermodynamic calculation. Experimental assessments were conducted to examine the impact of high-silica waste materials on the dissolution, melting and fluidity. Potential recipes for glass and mineral-wool manufacturing were suggested and an assessment of the energy savings, and reduction in CO2 emissions with manufacturing of glass and mineral-wool using this innovative approach were included. It was determined that the processes could lead to a reduction of over 26 kg of CO2 emissions per 100 kg of new material used, primarily due to the utilisation of heat from slag and the accelerated smelting process.

Aug 21, 2024

By Kuzmitch O, Morozov A

The main direction in the mechanisation in the mines of the Donbas and the USSR is long-face technology with complexes on the base of hydraulic supports. On the base of the 30 year old experience of exploitation of the coal clearing systems the serious data about the behaviour of the contained rock, display of underground pressure 'on longwalls and preparatory workings have been accumulated. Exploitation works in mines of the USSR are carried out at different depths: from 1000m to 1200m. There are 26 mines in Donbas, which exceed the depth of 1000m. It is the mines of Donbas, where is a rich experience of the exploitation of coal seams in various conditions. Besides, there are wide variations on the factors of the extraction thickness, depth of seam, angle of dip, occurrence of gas dynamics and others. In many scientific establishments, and in Donetsk Polytechnical Institute also, there are scientific research/results, which can be of interest for the coal mining countries.The volume of coal mining from longwall system-mechanised walls in Donbas became stable at the end of the 70s at level of 70 percent. All the efforts to increase this level have not given any notable results, not saying about the technical-economical data, which gradually deteriorate. It shows that positive progress in using the technology for the long walls is over and it is necessary to find new ways of mechanisation of coal winning.

Jan 1, 1991

By A Black, A de Jo, J Cavanagh, J Harding

Acidic and metal-rich waters have been discharging from Sullivan Mine, West Coast, New Zealand since the closure of the mine during the early- 1990s. This has resulted in a decrease in pH from a background of 4.5 to 2.8 and an increase in metallic elements in nearby Rapid Stream. In addition to the chemical effects on Rapid Stream, a study of freshwater macro-invertebrates revealed the absence of most biota downstream from the discharge. An attempt is being made to use the Sullivan Mine as a case study of problem and remediation analysis.

Jan 1, 2003

By C Bonini, A Markham, P Whittle, B Pearson

"Mine-derived sedimentation in rivers can have significant impacts on the processes and features of the receiving environment and impact on communities reliant on this environment. However, identifying and quantifying the contribution of mine-derived sediment to the receiving environment can be complex. This is particularly the case in remote environments and where little/no baseline assessments have been undertaken. One approach that can be used involves sediment fingerprinting, whereby a unique tracer is identified within the mine-derived sediment to discriminate between mine- and non-mine derived sediment sources downstream. The technique typically involves sampling of sediment at upstream, control and impact sites and sites within the mine deposit. Laboratory analyses are run on all the samples to determine whether the chemical signature (eg presence/concentration of specific metals) differs between each group of samples. In complex environments where the mine-derived signature may be difficult to detect from a basic review of the data, or where sampling constraints may limit the number of samples for analyses, statistical methods can be used to help identify sediment groups. This paper provides a mine case study to show how such an assessment can be undertaken despite the logistical challenges faced while working in remote environments.CITATION:Pearson, B, Markham, A, Bonini, C and Whittle, P, 2013. Fingerprinting and signatures - tracing mine impacts in complex aquatic systems, in Proceedings Water in Mining 2013, pp 287-292 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

A series of petrological studies were carried out on the characteristics of alteration and mineralisation in mainly structural-controlled (Deep Star, Meikle, Deep Post) and predominantly lithological-controlled (Post-Betze-Screamer and West Leeville) gold deposits in the northern district of the Carlin trend, Nevada. Alteration and mineralisation in these deposits are hosted in a sequence of calcareous clastic units of the Devonian Popovich Formation, into which have been emplaced a number of Jurassic intrusions, and syn- to post-mineral Eocene dikes. Four hydrothermal events have been recognised in these deposits: an initial Devonian base metal system and early diagenesis; a Mississippian stage of alteration in conjunction with burial metamorphism; contact and hydrothermal alteration and base metal-gold mineralisation associated with the emplacement of the Jurassic intrusions; and a Carlin-style gold system related to Eocene magmatism.

Jan 1, 2004

Times are changing for the mining industry. Civil society is demanding that miners pay more attention to the ways they impact on, and engage with, communities around their mines. Miners, in turn, are being forced to adapt and learn new social skills for which they were not originally trained. They are doing so in the middle of a broad resources boom, which is adding short-term operating challenges at the same time as miners need to be developing thoughtful solutions to longer term community issues. This paper examines a number of the issues that now loom on the horizon of mining companies. These include: human resources challenges and the crisis in minerals education; continuing community and social expectations of the resources industry and the impacts they will have, for example, on product stewardship, greenhouse gas emissions and the use of increasingly precious water resources; and current impediments to mineral exploration spending.It is concluded that the greatest challenge for the minerals industry is to develop a stronger cadre of local leaders and for the larger global miners to empower their local management to take on stronger public leadership responsibilities. There is a need for executive leadership to remember both the longer term and shorter term cyclical nature of the mining industry in developing solutions to community problems. Above all there is a compelling case for mining industry leaders to be more actively engaged with the wider community in the resolution of these issues.

Jan 1, 2005

By P J. Chapman

Recent catastrophic failures of tailings storage facilities (TSFs) continue to highlight the need for a detailed understanding of failure modes and the defences that are in place within the design to mitigate the failure modes. However, in many cases the instrumentation devices and monitoring approaches selected during operation do not link back to the design defences and inappropriate or redundant instrumentation is often installed. Candidate instruments and monitoring approaches (critical controls) are presented and matched to critical failure modes, with clear linkages to the intent of each instrument/monitoring approach. Commentary on where complementary measurements with independent technology types are recommended to provide greater assurance of trends to the design engineer or TSF owner is also presented. In response to the recent TSF failures, an increasing focus is being placed on instrumentation and monitoring relating to slope instability and safeguarding against the potential for static liquefaction, using a critical state soil mechanics framework. To support selection of appropriate zoning within a stability model, three complementary devices are recommended – vibrating wire piezometers to provide an indication of pore pressure and allow the phreatic surface to be inferred, tensiometers to confirm the presence of unsaturated conditions (and hence low potential for undrained failure) and moisture content sensors to provide an indication of void ratio, and hence state parameter, in saturated zones. The combination of VWPs and tensiometers will provide complementary measurements in the saturated and unsaturated zones, and also provide information on the extent of any near-saturated zones, provided that sufficient instruments are installed.

Jul 1, 2021

By M J. Nugus

The Geita gold mines in north-western Tanzania have produced 5 Moz of gold from an estimated endowment of 15 Moz. They are generally classified as typical Archaean orogenic banded iron formations (BIF)-hosted gold deposits in banded iron formations as described by Goldfarb, Groves and Gardoll (2001); Neall and Phillips (1987); Phillips and Powell (1993) and Neall (1987). The controls on gold mineralisation have been reassessed to conclude that Nyankanga, and we conclude that Nyankanga, the largest deposits within the group, developed during a dynamic and protracted deformation history intimately associated with several stages of hydrothermal fluid flow and alteration. The fluid-induced fractures associated with gold mineralisation are primarily manifested as submillimetre to metre-scale fractures and breccias developed preferentially in rocks that have been previously deformed and altered by silicification or seafloor metasomatism. This realisation detracts from the exploration and mining strategies that would solely concentrate on fluid pathways and associated wallrock alteration and veining solely within the BIFs as hosts for economic gold mineralisation.

Aug 22, 2011

By M I. Pownceby, S Hapugoda, H Han, V Nunna, L Lu

Charcoal produced from Syzygium Zeylanicum (local name: Yakada Maran = iron killer) trees were widely used in ancient Sri Lankan iron smelting practices. In this study, relict charcoal from Syzygium Zeylanicum tree trunks, branches and leaves were analysed for the first time. Unusually high concentrations of calcium oxalate (CaC2O4.H2O – CaOX) crystals were identified preserved in plant cell structures by optical mineralogy and SEM analysis. Thermogravimetric Analysis (TGA) of CaOX showed that it displayed three decomposition stages, releasing H2O at 177°C, CO at 493°C and CO2 at 750°C. Following the identification of CaOX in Sri Lankan charcoal, a series of reduction tests on a low-grade, high-P iron ore fine sample (high SiO2: 5 wt. per cent; Al2O3 4 wt. per cent; P: 0.135 wt. per cent) doped with CaOX were carried out at various temperatures. Samples were analysed by XRF, SEM and EPMA to determine the degree of reduction and the effect of reduction on the deportment of impurities, in particular P. Reduction tests at 800°C and 900°C with 5 wt. per cent CaOX showed that the reducibility increased to over 65 per cent. At temperatures above 900°C, P was located mainly within a fine, interstitial glass matrix suggesting that the CaOX flux enhanced removal of P from iron-rich pre-cursor phases to form glass. Preliminary magnetic separation tests to remove the P-rich interstitial glass were unsuccessful due to the fine grain size. Further complete reduction tests at temperatures above 1200°C with addition of coke to convert the iron oxides into Fem were conducted with samples doped with 10 wt. per cent CaOX, 10 wt. per cent CaCO3 and equivalent undoped samples. Results confirmed the preferential P-incorporation into a glassy matrix in the CaOX samples although some rare P incorporation into the metallic phase was noted. Experimental results, including comparisons with the CaCO3 fluxed and undoped samples, are discussed in view of the potential for CaOX flux for removing P (and potentially other impurities) from P-rich iron ores.

Nov 8, 2021

Accurate geometric models of orebodies establish the framework for reliable mineral resource estimates that provide a basis for further exploration and mine planning, as well as for financial models that ultimately determine the economic viability of a deposit. Traditional, explicit geometric modelling techniques that are utilised for resource modelling by the general mining software packages, such as MineSight«, involve manually digitising interpreted ore outlines that must be carefully linked to create valid geometric solid models. An alternative, implicit modelling method, employed by LeapfrogTM software relies on a fast method of global interpolation, which offers several advantages over traditional modelling techniques. Although previous case studies have documented the relative efficiencies of the two approaches, the accuracy of the two methods has not been previously quantified and compared. This study quantifies the accuracy of solid models created using explicit and implicit methods, and compares the differences between the models. Solid models of the Doris Hinge vein gold deposit (located in the Hope Bay district, Nunavut, Canada) are constructed from preliminary and follow-up drilling data using both modelling techniques. The accuracies of the solid models generated using preliminary drilling data are determined by measuring the 3D distance between the surface of the models and the actual contact location defined by the follow-up drilling data. Additional comparisons based on volume, cross-sectional area and surface differences were made between both phase 1 solid models and solid models constructed from phase 2 drilling information. The overall results of this study find that the MineSight« and LeapfrogTM solid model accuracies are virtually the same, and that their volume, cross-sectional area, and surface differences are comparable. This study concludes that the implicit modelling technique generates accurate solid models that can be used in place of explicit models as ore shells for resource estimation in certain circumstances.

Jan 1, 2006

In 1987 the control strategies at the then ZC Mines' New Broken Hill Consolidated concentrator were a miscellaneous mixture of computer hardware and technology for ISA, grinding and residue thickener control. Field instrumentation was based on current-to-air technology of approximately the 1960s. Decisions were made to rationalise computer and field instrumentation technologies; the object being to consolidate control loops into one system to enable expansion of the system to include all facets of plant operation. The first stage was to install a DEC Micro PDP 11/23 computer and serial line communication as recommended by AMDEL Ltd, for the ISA system, as discussed by Walsh and Freeman (1988). The second stage was to select and install a distributed control system for the centralisation of the control loops into one system, and to replace field instrumentation with state-of-the-art technology. This paper deals with the second stage of the rationalisation, in an attempt to give an insight into what is required when personnel are faced with such a decision, details of costs involved in keeping a system functioning and utilised; and the requirement to train personnel for acceptance of further control strategies.

Jan 1, 1991

With the theme of û æUnderground Ore Handling SystemÆ, Kopanang Mine completed an extensive project on a specific system with technologies for the handling of ore from a dedicated drawpoint to the shaft system. The intended rail haulage tramming system had to be capable of handling the shaft design and Life of Mine (LOM) requirements. Kopanang is an AngloGold Ashanti gold mine situated in the province of the Free State in South Africa. In the Sotho language the name æKopanangÆ means to come together as a team. ItÆs an appropriate name given that 25 companies worked on this project. The future focus at Kopanang is to establish four mining levels between 3 to 4 km south-west of the shaft and two mining levels to the west. The mine has an expected life of almost 20 years and capital was approved in order to access this reserve to establish the infrastructure to handle the ore, hence this exclusive rail haulage tramming system of close to R40 million (SA rands), which took three years to construct. Apart from the fact that this system had to be capable of handling 6500 t per shift at a depth of over 2 km over a length of 3.2 km, some of the major considering factors were: safety, economic factors with improved labour productivity, efficiency and reliability, risk termination, and ergonomics. The system comprises two 20 t locomotives operating in a double header configuration from a dedicated draw point to a dedicated tip area for the reef and waste ore. With the objective of handling high speed and high capacity, this 200 t payload train is capable of running at 35 km/h powered from a 500 volt ac overhead line. Each loco consists of two 90 kW dc motors with ac/dc power conversion on the locomotive. For the system to operate at this speed, the rail system is constructed with Class 1 rails over the entire hauling distance. The tipping mechanism is unique and the span of 11 hoppers each with a load of close to 20 t is capable of tipping the pay load of 200 t in about 20 seconds hands free.

Jan 1, 2005

By A M. Sardo, D E. Sinnett

This study uses the Q Method to examine how those living in former metal mining landscapes value this heritage and their preferences for the long-term management of mine waste. Such sites are often perceived as derelict or degraded, and of very little value. It is therefore assumed that their reuse, for example for development or recovery of metals, is likely to be beneficial. There are around 5,000 former metal mines in England and Wales, many of which are protected for their ecological, geological or cultural value. The Q Method is particularly suitable for issues where there is no consensus of opinion. We asked 38 residents of six mining areas in England and Wales to ‘sort’ a series of statements based on their resonance with the resident’s perspective; this is the Q sort. The statements covered a range of opinions of the mining legacy, its value and options for its management with a particular focus on the potential for metal recovery from the wastes. Analysis of the Q sorts revealed five perspectives on the mining heritage. All placed a high value on the cultural and ecological value of this heritage, however, they differed in their priorities for long-term management. For example, emphasis was placed on either nature conservation, cultural heritage, water quality or the opportunity for job creation through reworking the mines. Cutting across these themes there were also differing perspectives on the role of experts and local people in shaping the future management of the wastes. This research suggests that the views of local people are nuanced; they value their mining heritage but opinion is split on the most effective way to manage these sites especially where there is an impact on water quality.CITATION:Sinnett, D E and Sardo, A M, 2018. Former metal mining areas in England and Wales – local residents’ preferences for the management of wastes, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 126–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

The Jacobs Sliding Floor (Floor) is experiencing a surprisingly long competitive life. The first Floor was used on the Camino Tunnel in California in 1960. At that time the Robbins Company had built only seven TBMs, and the future for such machines was considered doubtful by many, as compared to drill and blast methods. This was then, and still is, commonly called the "conventional" method. Robbins' TBM No. 8 was for the Hydro Electricity Commission of Tasmania (HEC) for their Poatina Hydro Project in 1961. In this writer's view, the Poatina experience was the start of successful hard rock boring machines. But, by coincidence, the HEC is using the newest Floor for their King River Hydro project, where driving with the Floor started in July 1986 on the King Tunnel. This paper examines the history and developments in both Floor design and other "conventional" tunnelling equipment, and the site specific conditions that have allowed this old concept to still be competitive in certain select situations. Parametric costing data and some actual progress records are included.

Jan 1, 1987