The MinExTarget project’s aim to develop a new exploration tool is well under way. The MinExTarget tool provides better targeting capacities for early stages of mineral exploration based on secondary footprints of ore deposits preserved by heavy minerals in glacial, stream and shallow marine sediments. The project is funded by EIT RawMaterials.
Till sampling in MinExTarget prototype test area at Peräpohja belt, Finnish Lapland. Photo: Janne Kinnunen.
Sample preparation methods under way
The procedure for collecting samples has to be functional to make heavy minerals from surficial sediment samples benefit mineral exploration. Mineral separation from sediments is laborious and usually includes multiple processing and use of toxic heavy-liquids. In MinExTarget scientists are studying safer and cost-effective ways for heavy mineral separation from sediments.
“We have tested a possible procedure with Knelson and micropanning for pre-concentrating the till samples for later analytical purposes. The procedure seems very promising, but we still need more testing because the samples we got from one test area contained very low quantities of fresh sulphides”, tells Chief Geologist Hannu Ahola from Palsatech Oy.
Palsatech Oy have reviewed their heavy mineral separation facilities during the project. Further testing of the new procedure will start soon with new fresh samples from test area.
Heavy mineral separation is often made with toxic heavy liquids. CRS laboratories Oy has been testing separation with low toxicity polytungstate heavy-liquids for real and synthetic samples.
“We have been testing heavy liquids SPT (sodium polytungstate) and LST (lithium heteropolytungstate) which are liquids used to separate minerals according to their density. The aim is to get a heavier mineral separate than is usually possible without using toxic chemicals. This is done by working with heated heavy liquids which allow for even heavier liquids while keeping the work environment safe”, CEO Ville Anttila from CRS Laboratories Oy explains.
0.4mm pyrite grain from Mawson Oy study area. Photo: Hannu Ahola.
Pilot study
An internal pilot study was made by the Geological Survey of Finland – GTK in cooperation with Mawson Oy from the Rajapalot area in Finland to characterise the types of mineralisation in the area. The methods and techniques that are being developed in this test area will be expanded to cover different geological environments and styles of mineralisation.
“We also did till sampling in the active exploration area to delineate the continuation of the mineralised zone and potentially identify new mineralised zones”, explains MinExTarget Work Package Leader David Whitehead from the Geological Survey of Denmark and Greenland, GEUS.
“The paucity of sulfides in the samples from our test area may have turned out to be a good thing after all”, says Hugh O’Brien, Scientific Coordinator of the MinExTarget project. “It has forced us to rethink our strategy somewhat and realise that we cannot go into an area to do sampling with a fixed plan of what mineral we are going to target. In the test area we are now focusing on the trace element compositions of scheelite for ore vectoring, since scheelite occurs in the Rajapalot ore and has been found in our till samples. Additionally, we have a good idea of the age of the mineralisation event that is most important for gold in the area from previous studies. By measuring U-Pb ages on till-derived monazites, we will be able to help the exploration effort focus on those locations that give an indication of ages within the Au mineralisation window. Flexibility to target the trace element and isotopic compositions of a wide range of minerals will prove to be a great strength of the exploration tool we are developing.”
The sample separation, preparation and analytical work will be completed by the end of 2021 and the results of the internal pilot study can be reported to stakeholders.
Data and GIS compilation is ongoing in the project’s other test areas. Work is going on to create the necessary databases needed to analyse the different project areas, with the development of a system where data from different areas can easily be uploaded by different groups onto a central platform.
MinExTarget project’s test areas were chosen to present diverse sets of mineralisation types, but naturally we cannot cover all of them. Therefore a sufficiently big reference data set was required.
Now the compilation of database of LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) trace element data after careful literature review is ready.
“The database contains now more than 20 000 analyses for cassiterite, pyrite, chalcopyrite, apatite, scheelite, wolframite and more”, tells Professor Adam Piestrzyński from University of Science and Technology, AGH, Poland.
Webinars and workshop
The online short course “Fingerprinting techniques in mineral exploration” organised in June by MinExTarget in collaboration with EIT RawMaterials Academy, met all expectations. There were over 80 participants from 25 different countries attending the lectures. The practical part was limited to 25 students. “We had over 20 lectures given by experts all over the world during this one-week short course. The feedback from the attendees was really positive” tells Associate Professor Sabina Strmic-Palinkas from University of Tromsø – The Arctic University of Norway, UiT.
There are also new webinars on the fingerprinting theme in October. “Master and PhD students as well as professionals are invited to participate in the series of three online webinars on “Geochemical fingerprinting and indicator mineral research techniques in mineral exploration”. Webinar sessions will be on successive Fridays via Zoom video connection” explains Professor Pertti Sarala from University of Oulu.
The webinar series is organised by the MinExTarget project in cooperation with GTK’s Strategical development programme and collaboration with the Oulu Mining School.
“We are also organising a workshop on “Heavy mineral concentration and advanced identification techniques, and isotopic and trace element analytical techniques” later this year”, Sarala continues.
Education of Master students
The MinExTarget project is also devoted to the education of a new generation of professionals that will contribute to the sustainable and environmentally responsible exploration and exploitation of mineral resources in Europe. So far, 4 students successfully completed their Master projects focused on mineral, geochemical and stable isotope characterisation of copper and gold mineralisation and associated stream sediments in Norwegian terrains.
“We are very proud that all 4 students have already found relevant jobs in the mineral sector in Nordic countries” explains Strmic-Palinkas.
About MinExTarget
The project is led by the Geological Survey of Finland. Members of the consortium are: Geological Survey of Denmark and Greenland, University of Oulu (Mining School and Business School), UiT The Arctic University of Norway, AGH University of Science and Technology, CRS Laboratories Oy, Palsatech Oy and Mawson Oy.
About EIT RawMaterials
EIT RawMaterials is developing raw materials into a major strength for Europe. Minerals, metals and advanced materials are key enablers to achieve the objectives of the European Green Deal. Our ambition is to secure a sustainable raw materials supply by driving innovation, education and entrepreneurship along the value chain. We create a collaborative environment for breakthrough innovations by connecting business with academia, research and investment. We are strengthening Europe’s industrial competitiveness, innovation capacity and human capital basis. Our company is committed to supporting Europe’s transition to a circular, green and digital economy whilst strengthening its global competitiveness. On this foundation, EIT RawMaterials has been mandated by the European Commission to lead and manage the European Raw Materials Alliance (ERMA)
EIT RawMaterials is an Innovation Community within the European Institute of Innovation and Technology (EIT), which drives innovation across Europe to find solutions to pressing global challenges.
