Events, News

Defence of PhD thesis on wastewater treatment

A PhD study at University of Oulu has been performed by Hanna Virpiranta as part of the Kolarctic CBC SEESIMA project. The topic is “Development of biological treatment for sulfate- and metals-containing cold mining-impacted waters”. Hanna will now defend the thesis on the 24th February 2023 at the Arina auditorium (TA105), Linnanmaa, Oulu.

The PhD study developed a biological treatment process suitable for cold regions, using sulfate-reducing bacteria. The sulfate-reducing bacteria were obtained from a sediment sample from the boreal region and were adapted to the cold conditions. Initially succinate was used as the carbon source, but the use of different lower-cost carbon sources was also studied (such as sewage sludge, peat and whey), as well as synthetic and actual mine wastewaters.

After initial batch experiments the studied continued with the use of a continuous up-flow biofilm reactor, the layout of which is depicted in the diagram above (from Virpiranta et al 2022). The sulfate-reducing bacteria consortium was found to be able to grow at temperatures as low as 6 degC. At a temperature of 11,7 degC the rate of removal of sulfate was 4500 mg/(litre.day) and 87% of the original sulfate was removed. The reduction of sulfate formed hydrogen sulphide that caused the precipitation of most of the metals present in the wastewater. A further application of the sulfate-reducing bacteria was also investigated for the bioregeneration of ion exchange resin used for further sulphate removal from the waterwater. In lab-scale column experiments the resin capacity was almost completely restored.

The results of this study provide valuable information about the use of biological sulfate reduction for the treatment of Mine-impacted waters in cold regions, and the combination of sulphate reduction and ion exchange as treatment methods.

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Joint Finnish-Russian wastewater study published

In the SEESIMA project collaboration was established between researchers at University of Oulu and the Kola Science Centre to study the treatment of mining wastewater. Absorbents produced from natural materials such as peat were modified to improve their performance, and tested for their efficiency at removing different heavy metals and sulphate under different conditions, such as acidity.

The work has recently been reported in a joint article: “Removal of sulfate and metals from wastewater of a mining enterprise by a dual sorbent system: a case study”. The authors were Eugenia Krasavtseva, Harshita Gogoi, Antion Svetlov, Tiina Leiviskä and Dmitriy Makarov.

The graph above shows the reduction in the strontium concentration achieved by the brucite (magnesium hydroxide) sorbent at different pre-treatment temperatures and ph levels. Before using the brucite sorbent the wastewater was treated with a modified peat sorbent to remove sulfate. The graph above shows a better removal efficiency at high pH, underlining the advantage of firstly removing sulfate in the dual-sorbent system. The article can be viewed and downloaded at the Mine Water and the Environment Journal.

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Defence of Vitalis Chipakwe’s PhD thesis

Vitalis Chipakwe has been working on a PhD study partly funded by the Kolarctic CBC SEESIMA project. The topic is “Application of Chemical Additives in Mineral Beneficiation – Implications on Grinding and Flotation”. Vitalis has now prepared the thesis and will be defending the thesis on the 21st February 2023 from 1000 to 1200, at Luleå Technical University, room F1031. The defence can also be followed online on Zoom at this link.

The PhD was concerned with investigating improvements to the size reduction process of mineral processing, which consume large amounts of energy and are necessary to liberate the valuable components from the rest of the ore. The size reduction also traditionally uses large amounts of water, which then requires waste water treatment.

The initial part of Vitalis’ study was concerned with the dry grinding process, that uses less water than traditional wet grinding. Dry grinding can reduce the water consumption, but also requires more energy than wet grinding. Additives that allow a reduction of the energy consumption were investigated, including natural polymer additives as an alternative to synthetic polymers.

The study then continued by studying the effect of the additives on the downstream separation process (such as flotation), as well as the effect of the additives on the energy consumption of traditional wet grinding.

Vitalis is now working as a Development Engineer at Boliden in Skellefteå.

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Vanadium recovery from spent iron sorbent

Collaboration between the Kolarctic CBC “SEESIMA” project and the Interreg Nord “VanProd” project has resulted in an article published in the Resources, Conservation and Recycling Journal. The article is entitled “Vanadium recovery from spent iron sorbent used for the treatment of mining influenced water” with Tiina Leiviskä from the University of Oulu as a co-author.

Flow diagram of the Vanadium recovery process

When mining influenced wastewater that contains vanadium is cleaned with an iron sorbent the sorbent eventually becomes saturated with vanadium and needs to be replaced. This study examined how the sorbent can be treated to recover the vanadium and regenerate the sorbent to allow it to be used again. The treatment was a two-step process involving regeneration of the sorbent with sodium hydoxide, followed by precipitation of the vanadium as calcium vanadate. Vanadium is an important additive in steelmaking, to improve the hardness and wear resistance.

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Nussir copper mine information meeting

Nussir A.S. is holding a public meeting (1800 – 1930 CEST 28 June 2021) to present information about the status of the process relating to the opening of the copper mine at Repparfjord in Finnmark, Northern Norway.

Due to COVID restrictions the number of places for physical attendance is limited, but the meeting is broadcast over www.ifinnmark.no.

  • CEO Øystein Rushfeldt will give the latest update on the plans for opening the mine.
  • Project Manager Odd Henning Grove will give an update on the progress on the industrial site.
  • Anstein Amundsen will present information about the sea deposition of tailings.
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SEESIMA project profiled on Kolarctic Programme webpage

As part of the regular profiling of projects financed by the EU Kolarctic CBC Programme, the Kolarctic Programme webpage included an article describing results from the SEESIMA project, published on 12th February 2021. This article attempts to give a “Popular Science” summary, with a focus on the possibilities to reduce the energy consumption of processes to reduce the size of minerals.

Pictured at right is one of the grinders at the Khibny PhosAgro mineral processing plant.

See the article here, and in Russian language here.

News, Weblog

Nussir eyeing a possible start in 2020

The planned mine at Repparfjord in Finnmark is edging closer to a start, after a decade of negotiations. The mining licence was received in February 2019 from the Norwegian Ministry for Trade, Industry and Fisheries. Despite some uncertainty created by the corona-virus it is still hoped to start operations in 2020.

The planned Nussir copper mine involves two deposits – at Ulveryggen/Gumppenjunni and Steinfjellet/Nussir. (Picture from Nussir, via High North News)

Planning and financing for the start of operations was underway, but faces some uncertainty regarding the recovery of the financial markets after the corona virus. The Managing Director still hopes to see the mine operations to start in 2020, according to a recent article in High North News.

Nussir plans to extract copper, silver and gold, and also will look into the development of technologies to recover platinum, palladium and tellurium. The delays from the permitting process have allowed the adoption of new technologies, such as the electrification of the mining operations. The demand for copper has also continued to grow, such as for electric vehicles, wind turbines and other forms for renewable energy.

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CAMM² seminar in Luleå 21-22 April 2020

Luleå Technical University is arranging a seminar on Exploration, Mining, Mineral Processing, Metallurgy and Environment. This arrangement is part of the Centre for Advanced Mining and Metallurgy (CAMM) which was established at LTU in 2010 as a strategic research area. More details about the CAMM² Centre can be found here.

Announcement for the CAMM² seminar in Luleå 21-22 April
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Bioprocess for reducing sulphate and nitrate in mine waste water

Forrum Recycling and Waste Solutions AB were nominated as one of three finalists for the Swedish Mining Innovation Award in 2019, for a microbiological-based wastewater treatment process for lowering the sulphate and nitrate content of mine waste water. The concept is being tested at pilot scale at LKAB Svappavaara and consists of a prefiltration stage and a free floating biobed reactor.

structures for microbes to attach to in wastewater treatment
Plastic pieces give a surface for the microbes to attach to, to prevent them being washed out with the water.

Most mines face challenges meeting discharge limits on the allowable amount of sulphates and nitrates in the mine waste water. A summary of the wastewater treatment solution developed by Fortum is presented in a Youtube video. Mine waste water treatment is a focus of work package WP5 in the SEESIMA project.

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Kirovsk Mining Museum educational resources

At the conclusion of the SEESIMA meetings in Apatity a visit was made to the JSC Apatit Museum in Kirovsk. This has impressively modern and comprehensive displays and education resources relating to the history of the region and the technologies for extraction of minerals from the local resources, in particular the operations of the JSC PhosAgro Apatit.

educational resources in Kirovsk Museum of JSC Apatit
The “Enrichment Hall” with displays of beneficiation processes (crushing, flotation and dewatering) of the PhosAgro process.

The Museum has a webpage which shows some of the content of the museum. The website also provides the possibility for taking a virtual tour of the museum.

  • Hall 1: History of the PhosAgro group
  • Hall 2: History of the JSC “Apatit” mine and processing
  • Hall 3: Display of gifts received by the enterprise
  • Hall 4: Details of the Khibiny Massif mineralogy
  • Hall 5: Mineral resources of the Kola Peninsula
  • Hall 6: Underground Mining
  • Hall 7: Open-pit Mining
  • Hall 8: Enrichment Department
  • Exhibition hall: “Everyday life and customs of the Russian Empire”
  • Clock tower: Display representing the different features of layers between the earth’s core and atmosphere.

At the time of our visit there were groups of school children and university students using the museum. It is a very useful resource for dissemination of information about the mining industry, and for highlighting for young persons the opportunities represented by the industry.