Conference Agenda

Tuesday, 13/July/2021:
3:20pm - 5:00pm

Location: Exhibition


The Effects Of Using Hydrogen Peroxide To Provide An Improved HDS Process

Jodie Evans1, Richard Morgan1, Richard Coulton2

1Siltbuster Ltd, United Kingdom; 2Materials Recovery Systems Ltd, United Kingdom

HDS treatment plants are effective active AMD remediation processes, comprising of two-stage systems using aeration as the oxidant. In this paper, the practicality of using H2O2 as an alternative oxidant to reduce to a single-stage HDS plant was assessed. Comparative trials were conducted (two-stage (conventional HDS) and single-stage processes) on a bench-scale HDS rig, treating a continuous flow of 150 mg/L Fe net alkaline synthetic mine water. Results demonstrate that HDS treatment plants can be modified to a single stage when using H2O2 without compromising water quality or dewatering capabilities (42% dewatered solid content) of the HDS process.

Distribution of Metals and Toxic Elements Between Carbonate, Sulfate, and Oxide Mineral Precipitates

Julie J. Kim1, Satish C.B. Myneni2, Catherine A. Peters1

1Department of Civil and Environmental Engineering, Princeton University, USA; 2Department of Geosciences, Princeton University, USA

Immobilization of toxic elements from pH adjusted sulfidic mine waters via coprecipitation in carbonate minerals was studied. To design toxic metal mitigation efforts and to assess permanence, it is important to know how trace elements distribute between mineral precipitates of different reactivity and stability under environmental conditions. Experiments using synthetic mine waters were conducted and various imaging and analytical approaches were coupled to image and quantify trace element uptake in precipitated mineral phases. In the copresence carbonate and oxide minerals, or carbonate and sulfate minerals, cadmium and zinc concentrations were consistently higher in calcium carbonate phases and demonstrated patterns of coprecipitation.

Geochemical sources and long-term implications of mine waste weathering, Cwmystwyth Mine, Wales

Rob Bowell2,3, Yulieth Marquinez1,2, Tim Jones2, Peter Braham2

1Palatine House, United Kingdom; 2Cardiff University, United Kingdom; 3SRK Consulting, United Kingdom

Evaluation of the distribution and leaching potential of lead, cadmium, and zinc from the Cwmystwyth Mine has been undertaken and demonstrated that metal leaching neutral mine drainage is being generated. Discharge water from mine workings, waste materials and outcrop generated some variations in terms of pH and metal concentration, with most samples showing alkaline results but higher metals from water that flows through the mine. The mine contributes a high metal load to the Ystwyth catchment. Contamination in the river is attributed to the water discharge and perhaps seepage from different mine tailings, adits and underground workings.

It is very unlikely that the site will be remediated by cover or removal of mine waste or by using passive treatment due to its topographical complexity, and the sensitive nature of the site, being within a protected Site of Special Scientific Interest (SSSI). Moreover, the data suggests that there have not been any improvements in terms of dissolved metals in the water when data was compared to historic values; hence the mine remains a potential source of metals to the catchment.

Modelling the Geochemical Behaviour of Desulfurized Tailings as a Moisture-Retaining Layer in Insulation Covers with Capillary Barrier Effects using MIN3P-THCm

Asif Qureshi, Bruno Bussière

Institut de recherche en mines et environnement (IRME), Université of Québec in Abitibi-Témiscamingue, Canada

A column laboratory experiment was performed to assess the hydrogeological, thermal, and geochemical behaviour of an insulation cover with capillary barrier effects (ICCBE) made of desulfurized tailings as the moisture-retaining layer and non-acid generating crushed rocks as the protective and the capillary break layer. The ICCBE was represented in a numerical model developed using MIN3P-THCm. The model simulated the thermal-hydrogeological-geochemical behaviour of the tested ICCBE. The laboratory tests and short-term modelling showed that the tested desulfurized tailings do not generate contaminants at a concentration higher than the regulatory limits and that they can be used as cover material in a typical arctic climate. The preliminary long-term modelling results also suggest that the column will not generate acidity and maintain a leachate quality below the regulatory limits.

Assessment of the Chemical and Ecological Recovery of the Frongoch Stream Following Remediation at Frongoch Lead and Zinc Mine, Mid Wales

Paul John Edwards1, John F. Murphy2, J. Iwan Jones2, Chloe Morgan1, Rory P.D. Walsh3, Julie Gething1

1Natural Resources Wales, United Kingdom; 2Queen Mary University of London, United Kingdom; 3Swansea University, United Kingdom

Diversion of Frongoch Stream in 2011 reduced inflows to Frongoch Mine, increasing streamflow and diluting contaminants. This, together with subsequent surface water management, capping, hydroseeding and revegetation from 2013-2018, led to overall decreases of 87%, 93% and 87% for dissolved Zn, Pb and Cd respectively. Residual discharges, however, still cause the stream to fail to comply with Water Framework Directive standards and there is only modest evidence of biological recovery to date. Sediment metal concentrations in 2020 indicate that ecological recovery may be impaired by enduring bed-sediment contamination, even where erosion and sediment transport of mine waste is successfully managed.

Numerical Groundwater Flow Modelling In Support Of Mine Water Supply In An Endoreic Groundwater System, Tasiast Mine, Mauritania

Martin Boland1, Florent Boddaert1, Geoff Beale1, Glen Hein2, Pieter Labuschagne3, Ryan Cox4

1Piteau Associates, United Kingdom; 2Kinross Gold Corporation; 3GCS; 4GEM Ltd

Tasiast Mine is located on the western margin of the Sahara Desert. Water for mine operations is supplied from a wellfield located 60 km west of the mine site and 25 km from the Atlantic coast. Since 2012 a 3D numerical groundwater flow model has been used, and updated annually, as part of regulatory compliance. Unlike most groundwater systems, natural groundwater elevations at the wellfield are below mean sea level, and simulating the interaction between abstraction at the wellfield and the groundwater system at the coast is challenging, requiring the ocean to act as a recharge boundary rather than a discharge zone. A 1D SEEP-W model was developed to quantify the recharge deficit developed over time in the coastal plain, together with determining the depth below which evaporation stops. These outputs were incorporated into a 2D numerical model transect, representing 5km of the coastal plain, which determined the interaction between sea water intrusion and evaporation. Evaporation from the coastal plain becomes the dominant driver within the local water balance, with the upward flux from the coastal flats balancing the inflow rate from the ocean.

"Extension Of Measuring Points Network For The Upper Aquifers Of RAG Aktiengesellschaft Through The Drilling Pferdekamp"

Christine von Kleinsorgen

RAG Aktiengesellschaft, Germany

Before the planned rise of mine water, the existing measurement profiles "Tiefe Pegel Mitte" and "Tiefe Pegel Ost" of RAG Aktiengesellschaft needs to be expanded. Measuring points to monitor the hydrogeological status and the hydrochemistry in different groundwater levels, were created with which the water level before, during and after a rise in the mine water is monitored. For this purpose, the drillings Pferdekamp 1, 2 and 3 with depths of 780m, 355m and 90m respectively were created in Marl, Germany at the former location of the Auguste Victoria mine shaft 8.

Methods of Environmental Bioindication of Rivers Prone to Technogenic Salinization

Mikhail Baklanov1, Pavel Mikheev1,2, Olga Mikheeva3, Tatiana Sheina1, Elena Khayrulina1

1Federal State Autonomous Educational Institution of Higher Education “Perm State National Research University”, Perm, Perm, Russia; 2Khabarovsk Branch of the Federal State Budget Scientific Institution “Russian Federal Research Institute of Fisheries and Oceanography” (“KhabarovskNIRO”), Khabarovsk, Russia; 3Perm Branch of the Federal State Budget Scientific Institution “Russian Federal Research Institute of Fisheries and Oceanography” (“PermNIRO”), Perm, Russia

Indication of technogenic salinization in freshwater water bodies is an important tool for the detection of environmental degradation. Studies of the chemical composition of rivers of the Kama River basin prone to salinization were supplemented by an analysis of cyanobacterial-algal cenoses and communities of zooplankton, macrozoobenthos, and fish. In the most saline sections of the rivers, halophilic and euryhaline species of diatoms, zooplankton, and zoobenthos dominate; fish are absent. Moreover, we have tested the parasitological and haematological analysis of fish for the possibility of using it in the bioindication of lower and intermediate levels of salinization. The results show the possibility of using new markers of salinity found by means of parasitological and haematological analyses. The development and application of new methods of bioindication of technogenic salinization of rivers, along with the traditional chemical and biological techniques, are important for the assessment of the impact of anthropogenic stress factors on the biota.

Systematic Approach in Environmental Geochemistry as Part of a Mining Project Roadmap

Päivi Picken, Anneli Wichmann, Eeva-Leena Anttila, Kirsi-Marja Haanpää, Elin Siggberg

AFRY Finland Oy, Finland

Geochemistry data gaps often result from insufficient consideration of site-specific circumstances or poor conceptualisation. Whoever plans the first mine site soil sampling or analysis of process trial residues, must understand the many future uses of the data. Misconceptions of other data users´ requirements disable future assessments and cause delays in project schedule. A systematic approach in environmental geochemistry enables better assessments and better environmental risk management. The successful project toolkit includes a combination of tools like conceptualisation, repetitive risk assessment, knowledge base management, gap analysis, roadmap, action plan and sampling and analysis plan.

Repurposing Mine Sites For The Well-being Of Future Generations: Innovative Examples And Case Study Of Developing Post Mining Remedial Work In Wales

Peter Clive Stanley1, Trystan James1, Bob Vaughan1, Steven Pearce2

1Natural Resources Wales, United Kingdom; 2Mine Environment Management Ltd.

The Well-being of Future Generations (Wales) Act 2015 introduced “sustainability” into legislation for the first time anywhere in the world aiming to improve the social, economic, environmental and cultural well-being of Wales. Seven case studies are described showing how Natural Resources Wales acted “in accordance with the sustainable development principle” revealing how public bodies must act in a manner seeking to ensure the needs of the present are met without compromising the ability of future generations to meet their own needs. Public bodies undertaking substantial capital spending have a duty to ensure they embrace community well-being by applying their Well-being objectives.

Selective Recovery of Copper and Cobalt from Mine Effluent

Esther Takaluoma1, Tatiana Samarina1, Gershom Mwandila2, Leonard Kabondo2, Kawunga Nyirenda2, Phenny Mwaanga2

1Kajaani University of Applied Science, Ketunpolku 1, FI-87100 Kajaani, Finland; 2Copperbelt University, School of Mines and Mineral Sciences, 4662 Jambo Drive, Riverside, Kitwe, Zambia

Adsorption is a powerful tool to remove contaminants ions from water. In here, two major limitations of adsorption technique (the accumulation of exhausted waste-adsorbent and poor selectivity) are overcome by time-dependent selectivity and cycling of adsorbent by selective desorption. Real mine effluent containing 917 ± 92 mg Cu/L and 36,9 ± 3,7 mg Co/L was used as a real-life sample to demonstrate the ability to separate Cu and Co by means of adsorption on MgO with subsequent recovery copper by leaching and cobalt as sulfide. The sorption-desorption cycle was repeated 12 times, with little loss of capacity. A brief economic evaluation suggests, that the approach will become suitable after optimization of parameter.

Integrated Dynamic Mine Water Balance Modelling with EcoBalance Model Libraries

Kirsi-Marja Haanpää1, Jacobus J. Van Blerk2, Jacobus J.P. Vivier3, Eric K. Howell4, Rodolfo Avila4

1AFRY, Finland; 2AquiSim Consulting Pty Ltd; 3Artesium Consulting Services (Pty) Ltd; 4AFRY, Sweden

Integrated water balance modelling is a tool that assists in the critical mining industry task of water management planning. The process starts with conceptualisation, which includes identification and description of all relevant site water management structures and usually involves the introduction of simple water balance modelling spreadsheets. Irrespective of their complexity, these models are usually analytical and utilise a deterministic approach. For more flexible modelling and a better understanding of the water management scenarios, dynamic water balance models are applied. This paper presents how the Ecolego® software tool is used for integrated dynamic mine water balance modelling.

Evaluation Of Preferential Pathways For An Effective Dewatering And Depressurization Of The Aitik Open-Pit, Norrbotten, Sweden

Florent Boddaert1, Hannington Mwagalanyi2, Simon Sholl1, Geoff Beale1

1Piteau Associates, United Kingdom; 2Boliden Mineral AB, Boliden Aitik, Sweden

Boliden’s Aitik mine in northern Sweden has a mine plan which will deepen the pit to 850 mbgl by the end of mine life. The control on pit slope pore pressures becomes critical to ensure stable slopes and a safe operation. This often requires numerical groundwater modelling to support the geotechnical analysis. Following industry best practice, a multi-disciplinary approach has been adopted over different campaigns of characterisation to improve the understanding of source zones, pathways and magnitudes of water reaching the pit wall and floor. This enabled the construction of a detailed conceptual model, with a high level of confidence, that served as a basis for the construction of a 3D numerical groundwater flow model.

Utilisation Of Mine Water From Abandoned Mines - Example “Anthracite Mine Ibbenbüren”, Germany

Marion Maria Stemke, Georg Wieber

Johannes Gutenberg-Universität Mainz, Germany

Sustainable and environmentally friendly extraction of raw materials for energy and materials is playing an increasingly important role in security of supply. The European Union compiles a list of critical raw materials at regular intervals. On this basis, mine water from the Ibbenbüren coal mine were examined. The results show that critical elements occur in the mine water. The concentration increases with depth. For the flooded Westfeld, the elements Al, B, Co, Li, Mg, Sr and Zn could be determined in the outflow and the loads determined. The calculation of the geothermal potential shows that about 900 single-family homes could be supplied with heat from the freely discharging mine water.

Study on Mechanism Analysis and Treatment Measures of Karst Water Disaster in Mines

Weitao Liu, Lifu Pang, Yanhui Du

Shandong University of Science and Technology, China, People's Republic of

According to the theory of rock mechanics and fracture mechanics combined with the actual geological conditions of the coal seam floor, the coupling of water and rock is analyzed, and it is believed that the karst pore water pressure has a greater influence on the strength of the floor rock. The method of numerical simulation is used to analyze the stress change of the floor and the failure of the plastic zone during mining at a water pressure of 1-8 MPa. It is believed that when the water pressure is greater than 4 MPa, the floor has a greater impact.

Characterization of Arsenical Mud from Effluent Treatment of AU Concentration Plants, Minas Gerais – Brazil

Mariana Lemos1, Teresa Valente1, Paula Marinho1, Rita Fonseca3, José Gregório Filho2, José Augusto Dumont2, Juliana Ventura2, Itamar Delben4

1Institute of Earth Sciences, Pole of University of Minho, University of Minho, Portugal; 2Anglogold Ashanti, Mining & Technical, COO International, Brazil; 3Institute of Earth Sciences, Pole of University of Évora, University of Évora, Portugal; 4Microscopy Center, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.

The determination of the general properties of arsenical mud was carried out in effluent treatment plant of an Au metallurgical facility, located in Nova Lima, Minas Gerais, Brazil. This effluent, which comes from the calcination stage, is treated via Fe-coprecipitation / lime-neutralization and thus mud with high As concentration is generated. Instrumental methods were applied to investigate physical-chemical characteristics, such as pH, in addition to the forms of occurrence of As and its associations. The results indicated that the mud has an alkaline pH (» 8.5), particles with grain size below 20 µm, and As, Fe, S and Al concentrations above 5%. The element As is essentially associated with Fe, Ca, S, and Al, forming phases with wide compositional variation as major and minor constituents generically classified as "complex sulfates" and "compounds with S". The obtained results could assist optimization of the treatment routes in the plant and even to consider the potential reuse of this arsenic mud as a potential valuable product.

Mobility of Uranium in Groundwater-surface Water Systems in a Post-mining Context (Central Portugal)

Margarida Horta Antunes1, Paula Carvalho2, Teresa Albuquerque3, António Santos4

1University of Minho, Portugal; 2University of Coimbra, MARE – Marine and Environmental Science Centre, Department of Life Sciences, Coimbra, Portugal; 3Instituto Politécnico de Castelo Branco | CERNAS | QRural and ICT | Universidade de Évora; Portugal;; 4GeoBioTec, Department of Geosciences, University of Aveiro, Aveiro, Portugal

In uranium abandoned mine areas, particularly with mine tailings and open-pit lakes, the mobility of potentially toxic elements still acts as a source of surface and groundwater contamination. The water of open-pit lakes from Ribeira de Bôco mine and associated groundwater and surface water from the area is neutral and with low metal contents. However, some water samples are contaminated with Cd, Cr, Cu, Fe, Mn, As, and U and should not be used for human consumption or in agricultural activities. The baseline uranium threshold is considerably high for groundwater, which is supported by geogenic features and mining activities.

Overflow Estimation: A Study of MWN Pit Lake on East Borneo

Fahmi Syaifudin1, Yogi Pratama1, Karina Sujatmiko2

1PT Kaltim Prima Coal, Indonesia; 2Kansai University, Japan

The MWN pit lake was formed as a result of open-pit mining activities in one of the biggest coal mining companies in East Borneo, Indonesia. Forecasting the duration of pit lake filling and the subsequent overflow is important for a sustainable pit closure plan. This paper analyzes and predicts filling duration and overflow estimation using three different methods. Direct monitoring showed that the pit lake filling time is longer than the rational method and water balance calculation. The RSME between the direct calculation and water balance method is 4.71, while it is 14.6 with the rational method. Our result showed that the water balance method is a better approach for overflow forecasting. It showed that adjustment on input calculation parameter and calculation calibration is needed to get a precise estimation.

Hydrogeochemistry and Mineralogy of a River System in a Mining Region with a Cu-world-class Deposit in Mongolia

Soyol-Erdene Tseren-Ochir1,2, Teresa Maria Valente3, Tsermaa Kh2,4, Enkhdul T1,5, Munkhzul Davaadorj2,6,7, Boldbaatar Goosh2,6,8, Maria Amália Sequeira Braga3

1Department of Environmental and Forest Engineering, National University of Mongolia; 2Laboratory of Environmental Chemistry and Geochemistry, National University of Mongolia; 3Institute of Earth Sciences – pole of University of Minho, University of Minho, Braga, Portugal; 4Engineering Faculty, German Mongolian Institute for Resources and Technology, Nalaikh, Mongolia; 5Laboratory of Environmental Engineering and Clean technology, National University of Mongolia; 6Department of Chemical and Biological Engineering, National University of Mongolia; 7Water Agency, Ministry of Environment and Tourism, Mongolia; 8Water Supply and Sewerage Authority, Ulaanbaatar city Governance, Mongolia

The present work reports the environmental conditions of the Khangal River, under the influence of one of the biggest Cu mines in the world: the Erdenet mine, in North Central Mongolia. The results show that this River suffers the influence of the mining works and waste accumulations of the Erdenet Cu mine, although the neutral pH. The presence of calcite neutralizes the acidity of sulfides. In such alkaline conditions and in the absence of mineralogical control, elements such as Mo and As have high mobility, contaminating the ecosystem and preventing the use of water, either for consumption or for irrigation.

Acid Mine Drainage Precipitates At The Nanometric Scale – Properties And Environmental Role

Teresa Valente1, Ana Barroso1, Isabel Margarida Antunes1, Patricia Gomes1, Rita Fonseca2, Catarina Pinho2, Jorge Pamplona1, Maria Amália Sequeira Braga1, Juliana P.S. Sousa3

1Universidade do Minho, Portugal; 2Universidade de Évora; 3International Iberian Nanotechnology Laboratory

The mineral-water interactions responsible for mobilization of dissolved toxic elements in mine drainage often generate colloids that commonly occur at the nanometric scale. This study presents typical properties of these materials, mostly composed by iron-rich products. The samples were obtained in a variety of contexts, representing mine waters as well as natural acid rock drainage. Mineralogical results seem to confirm ferrihydrite forming nanoprecipitates at high pH and retaining arsenic. Further, the water properties could control the morphology and mineralogy of this very fine material, and consequently its environmental role.

Shear Behaviour of Compacted Gold Mine Tailings and Gold Mine Tailings Composite for Possible Use in Mine Backfilling.

Sisanda Prudence Gcasamba1, Koena Ramasenya1, Viswanath Vadapalli1, Stephen Ekolu2, Sammy Nyale1

1Council for Geoscience, South Africa; 2University of Johannesburg, South Africa

Utilisation of gold mine tailings (GMT) in mine reclamation requires a thorough understanding of its geotechnical characteristics. In this paper, a detailed experimental study carried on compacted gold mine tailings and gold mine tailings composite of varying curing ages is presented. Strength characteristics were investigated using consolidated drained (CD) and consolidated undrained (CU) triaxial tests under different confining pressures. The results obtained from the test showed that GMT composites exhibited higher strengths compared to untreated tailings. CD shear test revealed that GMT has a moderate capacity to withstand shear stress while the CU test showed an occurrence of static liquefaction.

Efficient Methodologies in the Treatment of Acid Water from Mines with Recovery of Byproducts

Osvaldo Aduvire1, Mayra Montesinos2, Nereyda Loza3

1SRK Consulting Peru, Peru; 2Pontifical Catholic University of Peru, Peru; 3SRK Consulting Peru, Peru

In general, the treatment of acid mine water is done via a one-stage process, at a determined pH level (Direct Treatment). In this article, a staged treatment methodology is presented (Staged Treatment), that makes the recovery of byproducts with economic value possible, as well as benefiting the environment by reducing contamination. This is achieved because we diminish the amount of non-usable slurry. For this reason, we will present the obtained results in Direct Treatment compared to those the Staged Treatment had, plus which byproducts were collected at different pH levels in the Staged Treatment. Finally, we will show flow.

Piloting a Sulfate Reduction System Using Chemical Precipitation for Wild Rice Waters

Lucinda Johnson, Meijun Cai, Shashi Rao, Adrian Hanson, ChanLan Chun, Sara Post, Alelxis Ward

University of Minnesota, United States of America

The Minnesota Pollution Control Agency (MPCA) has established a restrictive standard for sulfate of 10 mg/L in wild rice waters. Meeting this water quality standard is a special challenge for wastewater treatment facilities. Existing technologies (e.g., reverse osmosis; ultrafiltration) can achieve this standard, but are expensive and generate significant waste products. We are testing a chemical precipitation technology for removing sulfate cost-effectively, while also reducing the need for significant waste handling. Sulfate removal via barite precipitation has recently gained attention, as sulfate readily precipitates with barium salts as insoluble barium sulfate. It is not clear whether this application can be used cost effectively for municipal wastewater treatment, because that waste is dilute relative to other industrial waters (generally < 200 mg/L). We have previously demonstrated use barium chloride to precipitate sulfate (barite method) to levels below 10 mg/L. This led to a trailer-based demonstration system which will be tested at two wastewater treatment plants for two seasons. We discuss the results of our initial lab scale testing, as well as the results of the initial pilot scale deployment. Results are relevant to the mining industry, primarily for secondary treatment for polishing, following implementation of traditional treatment technologies.

Groundwater Nitrate Bioremediation of a Fractured Rock Aquifer System in South Africa

Paul Lourens1, Mariana Erasmus2, Robert Hansen3, Amy Allwright1

1Institute for Groundwater Studies, Faculty of Natural and Agricultural Sciences, University of the Free State; 2Saense Platform, Department of Microbial Biochemical and Food Biotechnology, Faculty of Natural and Agricultural Sciences, University of the Free State; 3Department of Geology, Faculty of Natural and Agricultural Sciences, University of the Free State

Due to the importance of groundwater in South Africa, the University of the Free State has successfully developed a zero waste bioremediation technology to treat nitrate pollution in water. Groundwater nitrate pollution of a fractured rock aquifer arose due to the storage of fertilizer effluent in unlined quarries. Numerical model simulations indicates that the proposed remediation removes the nitrate from the aquifer in a shorter timescale than the predicted natural attenuation. Treating the polluted water on site with the zero-waste bioremediation technique, and then re-injecting the treated water into the aquifer provides a holistic and sustainable solution to nitrate pollution.

Biological Treatment of Mining-Influenced Waters at Low Temperature

Hanna Heidi Anniina Virpiranta, Sanna Taskila, Tiina Leiviskä, Ville-Hermanni Sotaniemi, Jaakko Rämö, Juha Tanskanen

University of Oulu, Finland

Biological sulfate reduction is a widely studied treatment method for mining effluents containing sulfate and metals, especially at moderate temperatures. However, it is important to develop an efficient method for cold conditions also, as several mines operate in the Arctic region. In our previous study, consortia of sulfate-reducing bacteria (SRB) were enriched from a sediment sample collected from a mining area in northern Finland. After cold acclimation, the consortia were able to reduce sulfate at 6 °C with succinate as a carbon source. In a follow-up study, we used the consortia for sulfate reduction with low-cost carbon sources – whey from cheese manufacturing, natural peat, and conditioned sewage sludge – of which the sewage sludge was the most efficient. Further, we exploited the enriched SRB in a continuously operated up-flow bioreactor. The reactor was operated at near-neutral pH (7.0­–7.5) for the treatment of actual and synthetic acidic (pH 3.0±0.3) liquid streams containing sulfate and metals. Truly high sulfate reduction rate at temperature of 11.7±0.2°C was achieved. The SRB consortia have also been successfully tested for bio-regeneration of sulfate-laden anion exchangers.

UNEXMIN and UNEXUP Projects: Submersible Robots for Survey of Flooded Underground Mines. Showcasing Ecton Mine

Stephen Henley1,2

1Resources Computing International Ltd, United Kingdom; 2Ecton Mine Educational Trust

Submersible robots have been developed in the EU-funded UNEXMIN and UNEXUP projects, for surveying and exploration of flooded underground mines. They carry cameras and instrumentation to determine physical and chemical properties of wall rocks and water. On-board water samplers allow further laboratory analysis of the water.

Trials have been carried out at mines around Europe. Extensive dives yielded much new data on geology and archaeology, as well as the water which in one mine had been almost undisturbed since flooding to river level in the late 1850s. Some information is also presented on an important current project.

A short video shows tests of the first UNEXMIN robot at Ecton Mine, Staffordshire, UK

Floodplain Reconnection Stream Restoration In A Longwall Mining Region, Pennsylvania, USA

Natalie A Kruse Daniels1, Annika Gurrola1, Jordan Pazol1, Jacob South1, Nora Sullivan1, Jen Bowman1, Nicole Kirchner1, Ephraim Zimmerman2, Dave Goerman3

1Ohio University, United States of America; 2Western Pennsylvania Conservancy; 3Pennsylvania Department of Environmental Protection

This study tracks restoration projects in a longwall mine subsidence zone in western Pennsylvania, USA, that was completed using floodplain reconnection techniques rather than a more standard natural stream channel design. The restored sections are characterized by shallow, sinuous stream channels that readily inundate the adjacent floodplain wetlands. Floodplains are characterized with wetland microtopography with primarily wetland obligate and wetland functional plant communities. Upland tributaries are recontoured with lower maximum slope to reduce sediment transport and to reduce stream power into the main restored sections. Hydraulics, hydrology, sediment flux, and nutrient cycling and flux are being tracked simultaneously at quarterly intervals alongside deployed piezometers in both stream and wetland sections monitoring ongoing hydrology of the restored systems. Long-term water level data shows high frequency of floodplain inundation and channel flow and system discharge measurements show that there is a proportion of water that flows in the floodplain or hyporheic zone. This transient water storage can support dampened flood response when compared to the ‘flashy’ nature of most area streams, inundated floodplain wetland conditions driving nutrient cycling in the wetlands, and sustained perennial flow. These results suggest floodplain reconnection methods could be an alternative to natural channel design.

Scaling Passive Treatment Using Biopolymers for Lead and Zinc Removal from Metal Mine Pollution

Alice Lucy Slattery1, Tegan Imogen Allen1, Chris Hughes2, Luke Morgan3, Alex Finlay3, Hugh Christopher Greenwell1

1Department of Earth Science, Mountjoy Site, Durham University, United Kingdom DH1 3LE; 2X-Ray Minerals Ltd, Colwyn Bay, Conwy, Wales, United Kingdom LL29 7EF; 3Chemostrat Ltd, Buttington Cross Enterprise Park, Welshpool, United Kingdom SY21 8SL

Alginic acid is a polycarboxylated carbohydrate found in many species of seaweed, and has a very high affinity for dissolved metals. Whereas many small-scale experiments have been undertaken using alginic acid to trap dissolved metals, very little has been done to undertake scale-up to treat mine water discharge at significant flow rates. Here, data is presented from intermediate-scale trials with passive filter beds upto 1000 L bed volume, treating adit discharge waters of the Pugh's Adit, Cwmystwyth Mine, Wales, UK to remove Pb2+, Zn2+ and Cd2+. The inlet waters had concentrations of ca 300-800 ppb for Pb2+, and 18-22 ppm of Zn2+, with filters run for for periods of several weeks with a retention time of approximately 20 minutes. Metal removal and operational performance data for the trials are presented.