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By B McFadzean, N P. Lima, D A. Deglon

The reverse flotation of Itabirite iron ore is typically performed after a desliming step in which most of the sub-10 µm particles are removed. This is done to limit processing problems such as poor flotation recovery of SiO2 due to slime coatings and increased slurry viscosities, unmanageable froths and increased losses of hematite particles due to entrainment. However, the rejection of ultrafine particles contributes to large losses in iron recovery and may contribute to the instability of tailings dams. The aim of this study is to decouple the effects of ultrafine particles in the pulp and froth phases to better understand the processing capabilities of the fines fraction. The flotation test work was performed in a special-purpose continuously operated laboratory flotation cell that has a deep froth section to simulate plant-scale froth conditions. Five conditions of fines addition were investigated at three different froth heights and a solids concentration of 50 per cent. The behaviour of the pulp and the froth were decoupled using froth stability and froth recovery tests. This showed that, even though there is an exponential increase in froth stability at increasing fines quantities, the performance of the pulp has the overriding effect on the overall SiO2 recovery. Pulp zone, froth zone and overall SiO2 recoveries showed that overall recoveries increased by about 3.6 per cent for every 1 per cent decrease in fines content. This meant a large increase of 20 per cent in SiO2 recovery when going from undeslimed to deslimed feed. This was driven largely by increases in the pulp zone recoveries, which were about 4 per cent for every 1 per cent decrease in fines content. The froth recoveries, on the other hand, decreased by between 0.75 per cent and 2.5 per cent for every 1 per cent decrease in fines content, depending on froth height. This paper explores further insights into iron ore flotation processing at different slimes concentrations.

Aug 24, 2022

By Y Wang

Inadequate goaf gas control may lead to gas exceedances in the ventilation return air, which will trip power in longwalls and cause production stoppage. To effectively control gas emissions, Australian mines heavily rely on drilling vertical goaf holes to capture coalmine methane before it migrates to mine openings. The wide application of goaf gas drainage may change the goaf pressure distribution, lead to more ventilation air leakage, and consequently increase gas explosion and spontaneous combustion risks. This paper focuses on analysing goaf gas drainage production data from a case study longwall mine in Australia. The correlation between suction pressure, total flow rate, gas flow rate and air leakage rate were analysed in detail as the face-to-hole distance changes. Suction pressure is found to be positively correlated with total flow rate, and their correlation also varies at different goaf locations due to various goaf compaction and flow resistance. This paper also proposed a theoretical method to calculate the goaf resistance of ventilation air leakage pathways. Based on several basic assumptions and different goaf drainage scenarios, the leakage airflow pathway resistance in the goaf at different face-to-hole distances can be calculated. The model results suggested that the resistance of air leakage pathways from the working face to individual goaf holes increased with the face-to-hole distance. The resistance results can also be used to calculate the corresponding permeability at the same position, which can be used as input data for CFD or Ventsim models.

Oct 12, 2022

By P M. Hetherington, M P. Murphy, K E. Crook, F Pym

Resource characterisation is critical for informed decisions in both strategic and operational space. The sources of information for resource characterisation are limited by: direct measurement of resource attributes, such as grades, rock-types, mineralogy, and are available only from sparse locations, ie drill holes; or indirect geophysical measurements such as seismic, gravity or electro[1]magnetic survey. Data collection tools, methods, and processing technologies are constantly improving providing a broad spectrum of options for data collection strategies. The cost of each data survey varies from thousands to millions of dollars with the value of each additional data having diminishing return for a particular business decision. The value of information analysis provides the optimal decision on data collection strategy within a limited available budget. This work presents an example of value of information analysis for new Blast Hole Assay Tool (BHAT) and Reverse Circulation Grade Control (RCGC) data used in addition to the wider spaced exploration data. The value of information is quantified in terms of reduction of grade uncertainty, ore loss and dilution by comparing different combinations of data collection methods. Four different strategies were considered: exploration samples in addition to 50 per cent of blastholes surveyed with BHAT, exploration samples in addition to 33 per cent of blastholes surveyed with BHAT, exploration with wide-spaced RCGC data, and exploration without additional grade control. For each strategy the observed values have been simulated using advanced multivariate geostatistical simulations and compared with simulated ground truth models. The calculated uncertainty, ore loss and dilution informed the optimal data collection strategy. Opportunity to reduce sample density from the nominal 50 per cent of drill holes was evaluated.

Mar 22, 2022

By E Villaescusa, A Kusui, R Talebi, R Hassell, C Arcaro

Northern Star Resources (NSR) operates several seismically active mines as part of its Kalgoorlie Operations. In order to successfully continue mining at depth in increasing stress conditions, strategies need to be developed to reduce, control and manage the impact of seismicity causing damage to the rock mass. Consequently, a research partnership was developed with the WA School of Mines (WASM) through Mining3. The main aim of the project was to develop appropriate ground support standards that could withstand the expected dynamic response with minimal to no rehabilitation required for the life of that excavation. The project utilised a design methodology for determining the required energy demand based on detailed geotechnical mapping, probabilistic analysis of wedge formation and an estimate of rock ejection velocity based on uniaxial compressive strength of the intact rock (Villaescusa et al. 2016). The ground support scheme consists of high tensile chain link mesh, resin encapsulated de-coupled posimix bolts and plain strand cable bolts, in one, or multiple passes together with plain shotcrete. Implementation of the design posed several challenges including how to install the chain link mesh, maintaining the required productivity, ensuring quality control, and understanding the interaction of the several ground support components within the scheme. The implementation of the system within a trial area was successful from development mining to open stope extraction. The most significant field verification of the system occurred with near field M+1.9 seismic occurring in proximity to an operating long-hole drill. Despite large displacements exceeding 0.5m in places, there was no significant ejection of rock or failure of the ground support system. Following the successful trial, the ground support design methodology and standards have been implemented across several NSR sites. The system forms the basis for the successful extraction of resources in future high seismic risk areas.

Mar 15, 2021

By L Clarkson, D Williams, P Redcliffe, F van der Wal

This research presents a snapshot and insight into the trends, patterns, and common considerations identified in the current standing of real-time tailings dam monitoring practice. Based primarily on information derived from concurrent research by the author (in form of a Catalogue of Real-time Instrumentation and Monitoring Techniques for Tailings Dams), challenges and opportunities when transitioning to a real-time monitoring system are discussed. Learnings and key considerations between different monitoring approaches are explored, including themes of limitations and advantages that were observed consistently through global supplier feedback.

Jul 1, 2021

By J Northfield, L Neesham

The GRE46 Underground Project lies beneath the environmentally unique and culturally endowed shore of Lake Cowal. The ore body is open both along strike and at depth and is currently defined to a strike length of 1.5km and depth of 800m. The Warraga exploration decline commenced in March 2019 and represents the first stage of the Project, which is expected to underpin production at Cowal Gold Operations (CGO) for a period exceeding 10 years. Mining operations at Cowal commenced in 2005, following a period of over 20 years of exploration and permitting. In 2015 Evolution Mining (Cowal) Pty Limited (Evolution) acquired the operation from Barrick Gold Ltd (“Barrick”). Barrick had a life of mine plan that anticipated a cessation of operations in 2024 at a processing rate not exceeding 7.5 Mtpa. Evolution have grown the regional endowment considerably and have a currently approved mine life out to 2032 with a currently approved maximum processing rate of 9.8 Mtpa. This paper examines the history, current status and future path of one part of that plan, the GRE-46 Underground Project. Topics for discussion include discovery, Mineral Resource growth under different ownership philosophies, planning, permitting and commissioning of an exploration decline and bulk sampling project, and integration with the possible future mine. Environmental sensitivities affecting regulatory approvals, timeframes, technical challenges, opportunities and solutions are discussed, along with the path required to fast-track production from the existing 14Mt, 1.4Moz Mineral Resource while complying with the requirements of modern, responsible project development stewardship.

Mar 15, 2021

By M P. Sandy, R M. Stephenson

Portals to access underground mines are important infrastructure and their design requires careful consideration. Portals are generally expected to last for the life of the mine. Typically, the exposure of personnel and equipment is high, with many hundreds of movements through the portal per day. Consequently, the risk associated with geotechnical instability must be extremely low. Portals are often established from a boxcut. In areas where the weathering profile is well developed, the design and execution of the boxcut can involve significant effort, with the objective of minimizing the volume of the boxcut, whilst ensuring that conditions at the design depth are suitable for establishing a stable portal. Properly designed site investigations are a critical part of this process. Currently available portal design guidelines have not been updated for decades, however the equipment and ground support systems have changed significantly in recent years. Many mine portals have since been constructed in a relatively short time frame with success, often in challenging ground conditions using some of the more modern approaches to ground support. This is beneficial because delays in establishing a portal will generally delay other critical path activities, and lead to cost overruns.

Mar 15, 2021

By G P. S Resende, D E. G Oliveira, E A. S Baeta, T F. Bravin

There is currently in the mining industry, as well as in other industries, a movement seeking to increase investments in decarbonisation processes to help combat global warming. Among some initiatives taken is replacing diesel-powered mobile equipment in the mines with electricity-powered equipment, such as electric off-highway trucks or even belt conveyors in the mining operation. Samarco is a Brazilian mining company that since its conception has used a conveyor belt mining system in its mining operation, using only a small number of trucks to complement the mining process. This mining process that combines conveyor belts and trucks has brought environmental gains for the company since the environmental impact of conventional truck-only mining is greater than that of the combined system. To measure these gains, a medium-term mining plan was developed in which two fleet scenarios were detailed. One scenario contemplated a high level of detail of belt mining seeking its maximisation, while the other considered the operation performed 100 per cent by trucks, eliminating the use of conveyor belts. Through the comparison of these two scenarios, it was possible to make an inventory of atmospheric emissions and greenhouse gases for each one of them considering data such as types of equipment, diesel consumption, total distance travelled and energy consumption. The results showed that the fleet scenario with conveyor belts results in periods with up to 15 per cent less greenhouse gas emissions and 37 per cent less total particulates compared with the truck-only scenario. Therefore, the results confirm the environmental benefits of the method and the need to look for ways to even expand it in future operations through a study to identify the potential areas in the long-term mining plan.

Sep 18, 2023

By A Mortazavi, M Akhmedya

Mining is recognised as being one of the most dangerous industries in the world due to the difficult working conditions. Working in such hazardous circumstances in an underground mine often results in a variety of accidents. The working conditions at Kazakhstan’s underground mines have deteriorated owing to a lack of a risk-reduction plan and methodology. This paper evaluates different underground mines in Kazakhstan and demonstrates the employed mining method and the observed failure modes. Risk assessment has long been recognised as a valuable technique for preventing accidents. In the underground mining sector, risk assessment tools play an important role in avoiding work-related accidents. However, geotechnical uncertainty is a significant source of severe incidents like stress-induced roof collapse, wedge failure, seismicity etc, which result in human and financial losses. A geotechnical risk assessment performed early in the mine design process might assist justify a different mine design component, such as different support systems for a dangerous location within the mine openings during mining. The goal of this research is to create a damage/failure database aiming at the development of a geomechanical risk assessment methodology. This work identifies a thematic structure linked to risk assessment and management for the examined Kazakhstan mining sector. As part of the developed database, the dominant modes of failure within the Kazakhstan underground mining conditions were investigated. The study will provide opportunities to establish future research objectives for Kazakhstan’s mining industry where there are significant gaps between state-of-the-art research and mining operations in practice.

Nov 29, 2022

By T Zhao, K Wang, Z Zhang

Tailings pond safety monitoring is vital for preventing dam failures and ensuring environmental safety. Unmanned Aerial Vehicles (UAVs) can enhance tailings pond monitoring with flexible operational cycles and the ability to collect remote sensing data from inaccessible areas. While many mining operations have adopted UAVs for tailings pond management, their full potential in data acquisition and subsequent analytical processing remains largely untapped. This paper explores various case studies where UAVs have been utilised for monitoring key aspects of tailings ponds such as beach line indicators, dam displacement and erosion, slurry discharge processes, and tailings pond capacity. We also present examples where data derived from UAVs have been instrumental in slope stability analysis, seepage modelling, Tailings Dam Breach Analysis (TDBA), and risk prediction. By integrating UAV technology with traditional ground-based sensor techniques, this approach significantly enhances the precision and reliability of hazard prevention and management in tailings pond operations.

Sep 1, 2024

By B Darlington, L Sandberg, O Vallati

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

Nov 29, 2022

By I Auranen, J Raatikainen

IMA Engineering (IMA) and Mine On-Line Service (MOLS) companies have used on-line sensors for analysing ore and waste rock in mining for more than 25 years. Today IMA on-line sensors are used in various stages of the mining process including on-line analysis of drill cores, drill chips, ore and waste in loader bucket, ROM ore analysis on belt conveyor belt and in bulk ore sorting and in slurry analysis in concentrators. During years of extensive field experience and testing we have found that the waste rock dilution and ore losses create much larger economic and environmental losses than has been previously recognized. According to our studies the main reason is limited number of analysis already in exploration when drill cores or drill cuttings are used in block modelling. The same happens in production because too few and biased samples from benches are used to estimate the ore grade. Much more than today estimated amount of waste enters the mill and considerable volumes of ore losses happen at the same time. The ore grade on the benches and in muck piles is averaged and “homogenized” with averaged and biased samples. These are the main root causes of waste rock dilution and ore losses. Sensor based preconcentration can be the remedy to waste rock dilution and ore losses. This presentation will show examples of the use of on-line sensors in preconcentration when analysing ore and waste rock in drill cores, drill cuttings, on conveyor belt and in bulk ore sorting. Waste rock removal in preconcentration has direct effect on energy consumption in crushing and grinding and chemicals in concentrator. In concentrator waste is separated and goes to tailings pond, however, preconcentration directly reduces the volume of the tailings. In our presentation we will cover cases in base metals and in gold mines.

Nov 10, 2020

By N J. Potter, N W. Brand, J M. F Clout

The increasing demand for iron ore with low concentrations of trace elements, puts increasing pressure on iron ore producers for high-quality material. Understanding the mineralogy, petrography, chemistry, and mineral association of iron ore deposits is becoming increasingly important to provide iron ore products that meet the ever-increasing standards of steel mills. Limited attention has been paid to documenting new orebodies beyond bulk RC drill chip assays and product specification data. Therefore, limited information is known about the spatial distribution of minor and trace elements at the hand specimen scale, and elemental deportment within different ore and gangue minerals. In this study, samples from high-grade microplaty hematite, supergene-enriched martite-goethite and hematite iron ores are examined for their elemental and mineral associations. These samples contain distinctive minor and trace element distributions, with the mapping of deleterious elements (eg Zn, As, Cu) enabling the deportment and abundance within the ore and gangue minerals to be assessed. Results from this study show a diverse range of minor and trace mineralogy that are present in typical iron ore samples, in abundances below the detection limit of routine XRD scans, that host the deleterious elements, including but not limited to, sphalerite (Zn and S), chalcopyrite (Cu and S), xenotime (P and Y), apatite (P and Ca), cryptomelane (K and Mn), barite (Ba and S), alkaline feldspar (K, Al and Si) zircon (Zr and Si) and chromite (Cr and Al). The presence of these minerals and associated deleterious elements, even at low concentrations, has implications for producers, with the ongoing restrictions and tightening of environmental constraints in shipped iron ore products. By understanding the distribution and location of these elements within the iron ore, steps can be considered to maintain increasingly higher quality iron ore supply around the world.

Nov 8, 2021

By M Lee, J F. Carswell, G Reitsema

"The increased costs of underground mining have continually challenged engineers to identify opportunities for alternatives to common approaches to underground development. Considerations to the design of horizontal and vertical development at the Dugald River mine targeted inclined raise boring to reduce horizontal development, not only to reduce cost, but to allow development activities to focus on other areas of the mine.The mine plan consists of 50 raise bored ventilation shafts, of which 17 have been mined to date with diameters ranging from 3.1 m to 5 m and lengths from 30 m to 200 m. The expected performance and stability of these shafts has been determined using methodologies proposed by McCracken and Stacey (1989) and further refined by Peck, Coombes and Lee (2011). Actual raise performances have been collated and compared to a database of raise bore performances across Australia as presented by Coombes, Lee and Peck (2011), and form a database of raise bore performance specific to Dugald River.Opportunities to further optimise the mine plan and reduce costs have seen the introduction of large diameter-inclined raise bored ventilation shafts to minimise the required lateral development to connect the ventilation circuits. Large diameter inclined shafts ranging between 3.1 m and 4.5 m in diameter have been successfully mined with dips down to 70°, reducing the cost of lateral development by more than $1 million over the next two years.Both technical and operational challenges were overcome in the mining of large diameter-inclined raise bores, including modification of: existing methodologies of assessing shaft wall stability for inclined raises. These included variations of the McCracken and Stacey method and the utilisation of the modified stability number (N’) previously developed for stope performance (Potvin, 1988). both the collar and toe development profiles, including the general set-up of the raise bore drill rig to reduce the operational risks associated with angled raises.Due to their success, inclined raises have been designed for subsequent stages of the life-of-mine ventilation system at Dugald River. This has resulted in significant capital cost savings for the mine.CITATION:Carswell, J F, Reitsema, G and Lee, M, 2017. Vertical and inclined raise bore performance at Dugald River mine, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 313–320 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 16, 2017

By K White, R Hardie, J Merritt, B Kirsch, R Lucas

Constructed stream diversions are a common element of mine sites across Australia. A review of constructed stream diversion performance in the Bowen Basin funded by the Australian Coal Association Research Program (ACARP) in 1999 found over 80 per cent of constructed stream diversions failed to meet regulator and operator expectations. Since that time, improvements have been made in the assessment, design, monitoring and management of constructed stream diversions. Fundamental to these improvements has been the development of a better understanding of the regional stream systems and efforts to replicate the natural stream processes in the function and operation of constructed stream diversions.This paper discusses the history of constructed stream diversions through the Bowen Basin in central Queensland recorded in the outcomes of a series of ACARP funded research projects. Further, the paper reports on the outcomes of a current ACARP funded project that has reviewed the success or otherwise of constructed stream diversions in the region. The assessment has compared the performance of diversions that have been designed to replicate and provide for ongoing stream geomorphic processes with those diversions that were designed and built prior to the development of these design improvements. Based on these investigations we have identified design and construction successes and issues requiring further research and management attention.CITATION:White, K, Lucas, R, Hardie, R, Merritt, J and Kirsch, B, 2013. Challenges and opportunities for constructed stream diversions in the Bowen Basin, Central Queensland, in Proceedings Water in Mining 2013 , pp 73-82 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By S Larbi-Bram, F Shi, E Manlapig

Mining companies have recognised that characterisation of particle breakage plays an essential role in the design and optimisation of comminution circuits. Recently the JKMRC comminution research team has developed a new breakage model incorporating the effect of particle size, and a new breakage characterisation testing device, called the JK Rotary Breakage Tester (JKRBT), which allows rapid testing of particle breakage under high energy single impact and low energy repetitive impact conditions. The latter is believed to be the dominant breakage mechanism in AG/SAG mills. Existing devices, such as the JKMRC Drop Weight Tester, are not suitable for performing repetitive impacts since they are too time consuming. Positive feedback received from mining company sponsors to the new technology has prompted the JKMRC to further validate the device and the model through a formalised experimental test program on professionally designed and manufactured JKRBT machines. The first JKRBT was installed at the Anglo Research laboratory in Johannesburg in March 2007 and four more major mining companies will participate in the project in 2008, with commercial release expected in early 2009. The JKRBT has the potential to revolutionise ore testing, with applications in laboratory impact breakage characterisation of rock samples, drill cores, coal and other materials. It also stands poised to significantly advance the process control of comminution circuits since it is readily adaptable to on-line ore hardness measurement. Can any mine afford to miss out on this technology?

Jan 1, 2008

By P A. Grossman, J H. Rubinstein, M Brazil, K G. Sirinanda

To date, the scheduling and access design of an underground mine have only been considered as two separate optimisation problems. First, access to the mine is designed and then the scheduling is completed. One drawback of this approach is that the costs of access construction fail to be reflected in the net present value (NPV) calculation. In this paper, designing the access and scheduling its construction are formulated as a single optimisation problem.The underground mine access construction process can be classified according to the number of faces being developed concurrently. An underground mine with a single decline branching at a junction point into two declines is considered. After construction reaches the junction, the two faces of the decline can be constructed sequentially or concurrently.This paper proposes an efficient algorithm for optimally locating a junction point to maximise the NPV where two faces are being developed concurrently. The NPV is defined by taking the locations of orebodies and their values, decline construction costs, decline development rate and discount rate into account. The variation of the NPV and the optimal locations of the junction point for one and two concurrent development faces for a range of discount rates are discussed and compared. The proposed algorithm is applied in a simulated case study based on hypothetical values for an underground mine.CITATION:Sirinanda, K G, Brazil, M, Grossman, P A, Rubinstein, J H and Thomas, D A, 2014. Strategic underground mine access design to maximise the net present value, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 235–242 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By N Ganjian, A Delavar, F Rashidi Nejad

Iran is one of the most seismically active countries in the world, being crossed by several major fault lines that cover at least 90 per cent of the country. As a result, earthquakes in Iran occur often and are destructive. So, it is important to consider the seismic stability and reliability of all structures including tailings dams.In this study, the tailings dam stability of the Sangan Iron Ore Mine in Khorasan Razavi, Iran is considered for the case study. The tailings storage facilities of the mine have three cells with the capacity of 45 million cubic metres. The first cell, which has three stages of dam raising, has been recently brought into operation. This cell has a downstream-raised retaining embankment. As the risk of seismicity in this area is high, seismic response of this dam was evaluated by numerical methods. To do this, appropriate models were developed for materials used in foundation and body of the embankment. Then for seismic stability analysis, Tabas (Iran – 1978) and Chi-Chi (Taiwan – 1999) earthquake acceleration simulations were applied.The results of this study indicated that the upstream portion of Stage 3 of the dam and dam crest did not experience significant horizontal displacements during earthquake period, but the downstream portion of Stage 3 of the dam showed a maximum horizontal displacement of 60 cm at the third stage of dam raising. This is three times more than what was estimated by the designer. Also, the maximum vertical displacement resulting from simulation of the Tabas earthquake was 35 cm. The results of dam response to Tabas and Chi-Chi earthquakes indicate that displacement, shear stress and pore pressure by the Tabas earthquake were higher than the case of Chi-Chi earthquake. The higher energy of Tabas earthquake and the higher frequency near to the natural frequency of Tabas earthquake could be the reasons of this difference. The results of this case study confirm that if the studied tailings dam impacted by an earthquake of a similar magnitude to Tabas, the dam will be seismically stable and the developed strains will not be significant.CITATION:Delavar, A, Rashidi Nejad, F and Ganjian, N, 2015. Seismic stability analysis of Sangan Iron Mine Project tailings dam, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 173–182 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By D Blair, L Fergusson, G Barros

"The purpose of this paper is to present the findings of a waste rock remediation program conducted at a gold mine in New South Wales (NSW) over a six-year period. The treatment of waste rock dumps included the longitudinal results of one-off applications using: ViroMine Technology, including the application of a chemical reagent called Terra B, which is a benign, clay-like substance derived from processed bauxite and other sources lime and biosolids (added for nutrient value) clay capping and topsoil compared treatment outcomes from these three approaches to a control.Parameters measured in the program included leachate pH, total actual acidity (TAA) and chromium reducible sulfur (CRS), Al, Cd, Cu, Fe, Mn, Ni, Pb, Zn, and tree height and vegetative cover density with data collected at regular intervals over a six-year monitoring period. Findings over the life of the study indicated, for example, that leachate pH in the control area was 4.5 in year 1 falling to 4.0 by year 6; pH in the lime and capping treated waste rock was initially raised to about 5.5 after treatment but fell to 5.0 within 24 months and remained a low 4.7 by year 6; pH in the Terra B waste rock was 6.8 in year 1 immediately after treatment, and actually increased to 7.3 by year 6 with no further treatment. This finding is of relevance because it effectively profiles the acidity curves of waste rock control, lime, and capping applications, and shows that they decline over time, despite an initial æpH shockÆ to the solids as measured by TAA and CRS in the case of lime. Similar treatment curves were observed for heavy metal leachates. Tree height and vegetative cover density indicated that with increasing acidity in the waste rock dump, the lime and capping options did not allow healthy revegetation, but in the Terra B treated areas tree growth and density were comparable to background, undisturbed forest levels.is needed with respect to tailings management, based on a novel integrated research framework.CITATION:Fergusson, L, Blair, D and Barros, G, 2012. Sustainable waste rock remediation and revegetation - A real-world longitudinal study comparing ViroMine technology to standard applications and doing nothing, in Proceedings Life-of-Mine 2012 , pp 249-258 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

By P B. Schwann

The commonly accepted genetic theories of Pilbara iron ores and Woodie Woodie manganese ores have often presented them as quite unique. This apparent uniqueness is not confined to just iron and manganese, but is also seen in gold and copper deposits in Western Australia. The published material on iron and manganese ores would seem to have either a quite complicated genesis or none at all. An alternate theory for the origin of these deposits is presented which involves a protore with simple oxidation and pH controls with hydrothermal fluid sources from the diagenesis and dewatering of the underlying strata. This theory explains the distribution, thinning, cold dolerites and very high concentrations of deleterious minerals observed in these deposits. This genesis system is also related to the systems that deposit hydrothermal gold and copper in sediments in the region.This paper presents the author’s observations, sampling and mapping after several decades studying and exploring for the minerals in Australia and locations overseas. All of these theories were developed with (or in spite of!) the guidance of Mal Kneeshaw, but would never have seen the light of day without him and the others presenting here. It is not what I would call scientifically polished, and possibly deserves more detailed studies; it is, however, presented as a discussion paper.CITATION:Schwann, P B, 2015. Related genesis for iron, manganese and gold-copper ores in Western Australia, in Proceedings Iron Ore 2015, pp 327–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015