44. Seeing the Rocks - New Ideas in the Kiruna Mining District, Northern Sweden

Hi everyone, and welcome to Discovery to Recovery. Pable being a geoscience stories from the world of our deposits. This podcast is brought to you by the Society of Economic Geologists. Our sponsor, Anglo-American, is a leading mining company with a diverse global portfolio. Driven by its purpose of reimagining mining to improve people's lives, it provides many essential future-enabling metals and minerals for a cleaner, greener, more sustainable world. Their sponsorship supports the podcast and SEG. I'm Koray Tashvichan, a PhD student working on our deposits at the Colorado School of Mines, and I'm your host for this week's episode. In the last episode, we focused on the metallogenic and mineral systems in Northern Sweden, but I focused on electro-mining district. Today, we will pass the Arctic Circle and talk to geologists, who are exploring the incurable mining district with new ideas. First, we talked to Leslie Logan, a PhD candidate from the Ludiotecnico University in our project. She adopts a tectonic framework approach to reinterpret the co-occurrence of iron, copper, and gold deposits in Keiruna mining district. Then, we welcomed Marcelo Imanya, chief geologist from Copperstone Resources, to talk about Viscaria, a copper iron deposit history. After many years and companies, they have explored more than what was mine, and now they aim to start producing copper again, and the vicinity of the giant Keiruna ice mox out of the deposit. Welcome, Leslie, and thanks a lot for taking the time for us with a new one-dollar. So, how did you end up in Northern Sweden? Yeah, sure. Thanks for having me. I ended up in Sweden, actually, for multiple reasons, it's been a long road. I actually started my journey in Colorado, that's where I'm from, and I did my bachelors at the University of Wyoming, and through that bachelors, I had the opportunity to do a internship at the US Geological Survey in Denver, and it was the people there who really inspired me to specialize in orgyology, and motivated me to keep going with this. So, Al Hofstra, Erin Marsh, Mitchell Bennett, to name a few of the people who inspired me to keep going from the USGS. And after my time there, I was able to study at ETH Zurich, so I did my masters at ETH Zurich, and wanted to go there for their great program in orgyology, so I was lucky to go there and learn from some experts for two years. And then from Switzerland, I wanted to keep studying orgyology and pursue that to another level, and I found this position in Sweden to study this very complex area, and found that a very fascinating project to continue with. So, I accepted a position, PhD position in Sweden, and that's where I am today. So, your PhD focus is on the Kiruna Mining District. Could you please give a brief overview about the Kiruna Mining District's geology and ethnic background? Sure. The Kiruna Mining District is situated in northern Sweden in the Norbotton ore province, and it's actually interesting because you have the regional tectonic geology that is consistent throughout Norbotton, but Kiruna is actually slightly different in that it has one fewer folding phase and defamation event recorded in the rocks there. So, in Kiruna, you have bedrock that's deposited on top of an archaeine basement, and this bedrock includes green stone stratigraphy that was deposited during a rifting event, which happened around 2.5 to 2.1 billion years ago. And this rifting event then deposited volcanic plastic, volcanic and sedimentary rocks of this green stone aged stratigraphy. And then from there, there are rocks that were deposited on top of the green stones, and these came during the Sviko Kurelian Arrogony. And the Sviko Kurelian Arrogony is important regionally as an event that deposited many kinds of rocks. It had several suites of magnetic intrusions coming in at different times because it's a polyphase arrogony that came with at least two phases in northern Sweden. And so these rocks that are deposited on top of the green stones come from that phase. The early phase of the Sviko Kurelian Arrogony, it's interpreted to be a backark extension phase in Kiruna. And so there was some extension and then some rocks deposited there. And then came the magnetic intrusions. So mayphic defalsic in style that are also scattered around in the district and regionally. So this was during the first deformation event. And it was around 1.88 billion years ago, 1.89 to 1.86 or so. And that's when you had these rocks deposited with backark extension and followed by deformation. And then probably a bit of a tectonic pause until around 1.82 billion years ago. And then you had subduction occurring again and more magnetic intrusions forming in the region quite voluminously. And those ones marked this second deformation event around 1.80 or 1.82 to around 1.78. So those are the main two deformation events associated to the Sviko Kurelian Arrogony in northern Sweden. Some more deformation events are recorded over the Phenascandian shield. But in northern Sweden, we tend to go with these main deformation events. And as I said, Kurena has a more interesting geology in that there might be one less event recorded there. So this first deformation event in the upper stratigraphy, this later stratigraphy that was deposited, a foliation forming event that is formed elsewhere in the region doesn't seem to be recorded in those rocks in Kurena. There's one fewer folding phase. The foliation is either not there or it's masked. So this is interesting and has been interpreted by some of my colleagues to indicate that the Kurena mining district was at a higher crustal level during the first deformation event that it wasn't subjected to the same tectonic forces that would have led to a foliation forming event. And they have other structural data that backs that up as well. So that's a little bit on the background of the Kurena mining district and the Sviko Kurelian Arrogony, which really defines this structural framework of the region and of Kurena. Wow, that was a great answer. So you mentioned the progressive deformation events, we know that in the Kurena mining district there are some couple occurrences and the giant Kurena iron oxide and potassium deposits. So when you were proposing your K-shewer, what were the geological uncertainties in the area when you wanted to combine the fundamental geology with the ore deposit geology and the problems with the timing issue of these? Yeah, that's a great question and it really highlights the approach that we're taking behind my PhD work. So the tectonic background, we have a well-characterized structural framework that we're using then to understand how this manifests in the Kurena mining district. You have mineralization, as you said, it's the Kurena mining district is known for this giant Kurena of our iron oxide appetite deposit, that's what it's most famous for. But what is less famous for and what people don't know as much about is that there are several different styles of copper and copper gold mineralization in the district that haven't gotten as much attention, but they happen there. And this is something that sparks interest when it comes to the possible genetic relation between iron oxide appetite and iron oxide copper gold style of mineralization, because you have then this, of course, famous giant iron oxide appetite deposit, but then scattered around within 5 to 10 kilometers of this deposit, you have copper gold mineralization, not necessarily since you strict do iron oxide copper gold mineralization, but similar enough that several researchers have suggested that it's IOCG or that this is an IOCG district, Kurena and Norbotton. So then what we want to do is understand if there might be a genetic relationship between the iron oxide appetite and the IOCG mineralization, what can we say about it when we use the tectonic framework to constrain these mineralizations and when it comes to the timing? We have a polyphase erogyny that then led to different timings of mineralization, different timings of alteration and alteration of similar styles between the different deformation events. And you also have issues with radiometric dating sometimes in certain isotopic systems that are then reset by the later deformation events. So when you have these types of over printing relationships and complications, it makes it hard to use those as vectors to ore. So instead we want to use structural geology as a vector to ore and to characterize the different mineral system ingredients or or deposit characteristics through this structural geologic approach. So when it comes to the problems, we wanted to then understand what is the different timing or what is the timing of the copper gold mineralization compared to the iron oxide appetite mineralization. The iron oxide appetite mineralization is rather well constrained and accepted to have formed around one point eight eight billion years ago, which is correlating to the first phase of that spherical krillian erogyny. But with the ISCG mineralization with a copper gold mineralization, it's not known. Most of the deposits haven't been dated. There's one ISCG called Rackrady-Jarvey, which has been dated to be around one point eight six billion years. But there are a couple other deposits that haven't been dated. And the question is, are they from the same time? And if so, are they related to the iron oxide appetite mineralization mineralizing system? What kinds of ingredients did they share? And if not, what does that say about a possible relationship? If there is one, which we an I/OA and I/OCG mineralization. So what were the methods and how you implemented the structural framework in the kernel mining district? So we use the structural frameworker, the structural characterization of the region as a lens through which we assess the mineral system ingredients of the order deposits. It's kind of using the tectonic evolution as a lens to also look at the broader scale aspects of what forms the order deposits. So when I say mineral systems, I'm talking about this concept defined originally by Wybourne and others in 1994, which is describing mapable criteria for all of the ingredients necessary to form an order deposit. And these researchers have defined it as all order deposits need an energy drive, some sort, tectonism, magnetism, a metal source, a ligand source, transport pathways, and a trap to summarize. And so what we do then is we take a look at these different ingredients, which happen on many different scales, so deposit scale, regional scale. And we look at them through the lens of the regional tectonic evolution. So we use this approach by assessing all of the microstructural textures that we can to see the relative timing of these different mineralization events. So we use what we know about the first foliation forming event that we can associate to the first phase of the deformation of the SQL kernel in our region. And we know that this is a heterogeneously developed but pervasive fabric that reflects ductile conditions. So you should have maybe myelinitic fabrics, things that reflect higher pressure and temperature conditions. And then we know from the regional mapping as well that the second deformation event was more brittle ductile and character. So you have both brittle and ductile features somewhere at the transition. So you often have kind of both styles of microtectures forming. And we know this from this characterization, the structural characterization. And then we go in and we study the microtectures and we start to then apply more geologic questions based off of this when it comes to the separate ingredients of the mineral system. For example, when we want to understand the metal and ligand source, we have sampled rocks from these copper mineralizations to target microstructures that show a relationship of structures to ore mineralization. And then by assessing these microstructures in hand sample, also in out crop but also then in microscopy, we can then assess what is the relative timing of the mineralization. If we can see different structural characteristics that we can then align and define with what has been seen regionally. And then once we do that, we can start to assess some of the other types of characteristics about the rocks. For example, trace element geochemistry, what is the difference in your trace elements in sulfides that are in microstructures related to the early deformation event or have been there before the first deformation event? And what are the signatures of the sulfides that can then be assigned to this late deformation event? Sulfides that are sitting in an S2 fabric that have been remobilized into fold hinges or things that we can definitely characterize as having formed or been remobilized later on during that second deformation event. So that's the approach that we have done. I am a huge fan of mineral system support because I believe that you cannot find the same exact or deposit in any other part of the world because each deposit is unique and the geologic settings that they are situated in, they're also unique. So you will have different end products. So what were the outcomes of this mineral system support in Kirin or Mining District? Well, we've looked at a few different aspects of the mineral system. So for example, the energy drive, which we did by looking at the ages of magnetic intrusions in the district to understand when did you have a high heat flow and probably also fluid flows, hydrothermal circulation cells occurring in the district. So we've done some dating there and they've gotten primarily early originic ages for all of the intrusions in the district. So it definitely had an early originic phase of elevated geothermal energy and hydrothermal circulation going on, whereas we weren't able to confirm that there were any magnetic intrusions related to the late deformation event in the district, which is interesting because yeah, it's not that they don't exist regionally. This late originic magnetic suite is quite voluminous everywhere in Norrbotton, but in Kirin or at least at the current original level, we weren't able to find any. So this was one of the results when we looked at the energy drive and putting that into the framework, we then understand it's we have something related to this early phase of the origine. And then when we focused on the structural geology and transport pathways for mineralization, the traps as well, transport pathways and traps can be sometimes the same. So from that, we also were able to see that the copper mineralization in the southwest part of the Kirin district in an area called Potowara hosted in the green stone rocks there, but is epigenetic in style. So it cuts the green stone rocks. And by looking at the textures there, we were able to define the large scale fold there. And this fold hasn't been characterized within the tectonic framework. And by looking at the outcrop and the micro textures, we were able to see how there is actually an early preserved s1 foliation in these rocks there, despite it being masked or absent in the rocks higher up in the stratigraphy. It's not present there, but it is actually still recorded in this deeper green stone stratigraphy. And by seeing this early foliation, we also were able then to map structurally how this foliation is folded into this large scale fold. So we were able then to use that as a constraint to show that the fold there is an F2 fold. And that folding event then happened during the late phase of the SQL career in origine. That then leads to the important result, the mineralization in the pot volume area, the copper mineralization is situated in s2 foliation, s2 features. It cuts the fold or occurs sin tectonically with the fold. So we're able to then show that we have an epigenetic style of copper mineralization that came during the late phase of the SQL career in origine around 1.82 to 1.78 billion years ago. And that's approximately 40 to 80 billion years different than the accepted age of the Kirinavara iron oxide appetite deposit forming around 1.88 billion years ago. And then you have the structural geology that can then show that certain structures that host mineralization related to this late originic event much, much later. So that is something to say about the transport pathways and possibly traps that this late originic event was important for copper mineralization in that way. So we know, OK, something about late brittle ductile features was important for copper mineralization in it comes to the mineral system ingredients. And so that's also interesting. And then we also have been looking at the metal and ligand sources for this deposit utilizing the structural framework approach again. So looking at sulfides that can be structurally constrained into generations as being early originic or pre-originic sulfides that are situated in a foliated fabric for example, that you can then constrain to having been there during or before the first foliation event. And we have sulfides that are then situated in S2 fabrics that are cutting the earlier foliation and taking those sulfide generations and those sulfide grains and assessing their trace element and their sulfur isotope signatures. So this work is still in progress, but we're using this type of characterization then to see what is the difference in the trace element geochemistry and the sulfur isotope chemistry between these generations. What is recorded between the early and the late? Is there something big, something quite distinct? Or is there something that might show that these mineral system ingredients might be recycled? Because there are often signatures from other studies that show that it's quite mixed. You have mixed signatures for the fluid source, for the metal source. And also it's seemingly overprinted that you have similar alteration styles that seem to occur in the early originic event and the late originic event. And why are they similar and why aren't they just completely distinct? So what we're starting to hypothesize is that these specific ingredients of the mineral system may also be largely recycled. That you have ligands that have already been mobilized early on in the Rajani and then you have another energy driving event that then has the right conditions to mobilize again, ligands that were important for carrying metals. And then the metals as well, maybe some metals were already there or perhaps there was also a fresh input of metals for these later event to form then a late originic mineralization. But this is something that we're still working on, but part of the results of the bigger picture of the mineral systems in Kerenna, between iron oxide copper gold mineral systems and the iron oxide appetite mineral systems and how are they actually related or how do they overlap when it comes to this tectonic evolution? I mean, I'm fascinated. And I explained a lot of I was taking notes to ask based on your answers, but progressively you answered all of them. You mentioned to Rakhriyavya Bhattahawara. There is also Viscaria Copper deposit, which was mining back in 1980s and 1990s and then shut down now it's being explored by copper store resources, regarding all these three copper occurrences, Bhattahawara, Rakhriyavya Bhattahawara, and Viscaria. What do you think about the significance of copper mineralization, Indicurna mining industry? The importance of copper in this district is interesting because you have with the current proposed theories for how this copper mineralization have formed. You do have deposits that are suggested to have formed syn genetically with the deposition of the green stones and an exilative style of or formation, which includes Viscaria. It has been proposed to be this type of model and if that's the case, then we have a copper mineralization event associated to the extensional phase before the spherical career in origine that happened around 2.1 billion years ago. So you have pre enrichment of the district in copper if that's the case. And there's a or body in the Bhattahawara area as well that's suggested to be a similar origin. So maybe, or maybe not, but it could be that you have a pre enrichment of copper mineralization in the region in the green stone rocks. And the green stone rocks are important in other places in the world too. You have the Great Bear Magmatic Zone, I think as well, where you have green stone rocks that play a role and people have also wondered what the role of green stone rocks are when it comes to the iron oxide appetite of formation that may be iron sourced from the green stone rocks, so this hasn't really been backed up so well with data, but green stones having some enrichment of metals available. So then you have green stones forming and then you have an originic accretionary cycle that comes in with magmatic intrusions. So you have heat, you have fluid starting to flow, you have structures forming in ductile regimes and then later in brittle ductile regimes. And these structures then are allowing this hydrothermal fluid and the heat to then be transported, possibly through these green stone rocks. And what does that mean then for either remobilization or the formation of new mineralization later? And if the green stones have really contributed to this. So you have possibly a pre enrichment, then you have the first originic phase of the irogyny, which then you have the iron oxide appetite deposits forming then, but then you also have at least one, since you strict to ISCG deposit the rackety RV one that formed, not in the same tectonic regime, the iron oxide appetite deposit was formed during this backark extension phase and then during the crystal shortening phase, that's what can be linked to the rackety RV ISCG, so that then crystal shortening in ISCG formation. And then what we've seen in Potomara, which is 40 to 80 million years later, a brittle ductile event and another mineralization event with copper and gold in the green stone rocks as well. And so this sort of district where you have a lot of interesting ingredients that might make the perfect recipe for forming different ore deposits of different kinds, and maybe these types of ingredients in this recipe exists in other places in the world, maybe pre enrichment favorable rock types, the rite tectonic environment where you have maybe as a common denominator, certain structures that are commonly reactivated and acting then time and time again, both at the beginning, maybe in a rifting environment, backark rifting, and then crystal shortening where you have then the focusing of fluid flow through these structures and then being reactivated again upon different deformation events. So these structures may play an important role as a common denominator among the different deformation events that then help to form mineralization in certain areas where this fluid flow through the structures intersect favorable trap of some sort, like an iron oxide appetite deposit or like a reducing volcanic rocks. For example, graphite shists that are also present in the green stone stratigraphy. So these ingredients then that are all there. And that is sort of the bigger picture of these types of districts where all of these types of ingredients that would be useful when it comes to exploration and using them as vectors to ore. And you have to then see it a little bit from a broader lens. And then you can start to focus in on what are the true exploration targets that can be used. I would argue structures. For example, the brittle ductile late originate structures would be targetable criteria and where those structures intersect, reducing horizons for example. So the copper mineralization then is still a big part of the story of the Kierna district, even though it's known for the iron oxide appetite because it's such a huge deposit. But you still have all of this copper mineralization and that is important when it comes to the teconic evolution. And the teconic evolution has allowed for these deposits to form. And next, we welcome Marceli Mania from the Copperstone Resources. Marcel Lo, could you please introduce yourself? Thanks Koray. Yeah, we are very pleased to be here in this type of podcast. I think the story of Biscaria is something very, very cool to talk about. There are still more things that will come in the coming years. But just to give a brief background on why Peruvian geologists is working here north of the Arctic Circle. Well, I landed in this part of the planet 20 years ago. My background is in economic geology related from Peruvian universities. But I follow my career without changes. I mean, I focus all the time on the discovery parts of mineral deposits. And that's the reason I did the studies in Finland and in Sweden connected to mines from the auto-cumpe group, mines from the store-leading group. Since then, basically I embark on a global career, not only on the Nordics, but on the basically in several continents through working with Lundin with the first quantum minerals group on different continents. And mainly focus on BMS deposits and sediment-hosted carbonate-hosted base metal deposits. And I think these two things have something to do with my role here in Biscaria because in Finland, we were told that Biscaria is a BMS deposit. It's an exhalative deposit in certain types of sedimentary rocks. But I think things have changed and that's normal in geology. So yeah, I'm a fanatic of economic geology matters. So what are the challenges that you have had in Northern Sweden? We are up for the challenge. I think if you manage to explore in the, you know, in the remote areas of the Andes and some crazy places in different areas and deserts and jungles, I think the Nordics, it offers not a more difficult, it's just a different, a different way to deal with things. And things obviously needs to be learned on the practical side, but at the end of the day, we are dealing with rocks that have suffered possibly similar processes, but they end up with different preservation. And that's one of the main things when the Andean Geologists comes to work in the protozoic terrains of Northern Europe, is that perhaps people who have seen things and the form and metamorphose, you know, in situ and 3D exposure, and they might have better tools, much quicker understanding of what could have happened with something that has attained strong deformation or distortion. Obviously, the challenge in the Nordics here, we deal with lack of exposure. It's not the Andes, it's not Africa, it's a lot of cover, which is mainly glacial till cover. And that makes the geoscientists, explorers, to be more keen on indirect methods, like your physics and your chemistry. So it's constant, constant learning process, whatever you go, because things are different. The current resource of Biscari are more than what was mine back in 1990s. So what was Biscariol like when you started there and how the Biscariol look like today in terms of geological understanding? Well, first of all, four years ago, when we started here, Copperstone Group, it was a very small group. I think no more than seven people, and we were in the middle of the COVID situation, but we had this opportunity, all producing mine from Autopumpu times, and basically an underground mine that produced 12.5 million tons at 2.5 percent copper, mainly in sulfides, basically in copper sulfides. This type of deposits you don't see these days. And there was an important question from the beginning, why after almost 20 years that this operation was shut down, why not so many companies of people have tried to unlock the full potential of the area? And I say the full potential because Biscaria, it is a copper deposit that contains magnetite and contains iron, and that we got to know once we touch ground here, and it is located basically less than two kilometers away from a giant deposit, the Kiruna Vara iron appetite system. It's not only small distance that separates Biscaria and Kiruna, but another interesting relationship is that the ore bodies, they seem to be sat parallel in different statigraphies, but following and basically along the extent of the iron ore, they were the copper ore in one side. But also, many things paid, our attention is like, what type of systems can make it high-grade the position of copper sulfide for more than two, three, three and a half kilometers? That is that would be just a process controlled by thermal gradient that should have required an amazing, amazing, something that is almost impossible to believe that a copper system with such a high-grade could be constant for such a long distance along the strike. So obviously, there were things that we did not understand, there were many other things that upon drilling that has happened here in Biscaria, we get to see, to understand the relationships. Another challenge, well, if there was a challenge when we arrive here is that although the Kiruna region, it is a mining region, there has been and there are iron mines in operation, but it is northern Sweden, 200 kilometers north of the Arctic Circle, and I would say probably it might not be the priority number one list of geologists to come and explore, but so what happened is there was not a pool of people that we can start with, so we basically started from zero trying to find the people who would like to take this challenge, would like to join in this endeavor, and I think that was a very important part of the work, especially during the first two years, to try to get the team together, a team of geologists and geotechnicians that, not only from Sweden, but from many other northern countries and other parts of the world, which now I can tell that in the geology team, we are basically almost 50% of the copperstone embodies, a little bit more than 14 members right now. The 14 people represent almost 11 nationalities. I see this as a plus in terms of adding different point of view, adding different perspectives to a team, because people contribute with different experiences, different ways to solve problems. Just one more thing, at the starting point, when you deal with a past producing mine, you will get a lot of historic information. Sections, data, analysis, reports, many of these things, perhaps they were a little bit biased towards certain ways to deal with the subject, with the project, but there is information and every piece of information, it is important to digest, but just to keep the mind open. So that was once the main thing that we got to deal first. Getting the people, the good team around and start understanding all the story of information. Yeah, legacy data is very important, and as you just mentioned, you had the very largest legacy data set. So what were the initial expression challenges that you had at Miss Korea? Geologically speaking, I think the main challenge was to try to keep the people away from the models, from the exploration models. We tried to be very critical on what the new information we were obtaining, because we were drilling already. But on the viscosity deposit, what it also matters is the scale at what we start looking things. If we look things, in less than 100 meters, on the minus scale, everything might look like, okay, this is a stratiform deposit and it's concordant to the strata, to certain specific estatigraphy. But once we opened up that scale to look at the mineralization in, let's say, three or four kilometers, then we could understand that sulfide mineralizations sometimes are not confined to certain beds. When looking drill core in Miss Korea, and these days you utilize all these modern techniques with oriented drill core, download all your physics, and many, many good things that can give us a lot of information to validate and question against the chemical data, for instance. But still, the drill core itself is a chance to see textures, to see minerals, to see alterations, to see paragenesis. And that has not changed in 30, 40 years. And it is a valuable thing. One of the curiosities is that, although Miss Korea is an strata about the deposit and a lot of the mineralization follows certain certain horizons or packages. But when we see it in detail, we see that the mineralization is, a lot of that is in banks, banks that follow the cleavage, banks that are deformed along the cleavage. They are mainly with carbonate, gal material, so you can imagine that the pinching as well, situations will occur within this type of minerals. New questions, but also giving new answers. For the other aspects of the team you built, besides the diversity, that helped you be successful? Yes, I think to have a diversity on points of view and background is a plus. But also is a plus that our team basically is very young. So most of the people in the team, they are less than 30 years old. Basically recent graduates with a few years of experience, some others directly coming from university after the master degree. And I think the young people at the same time that they are very pushy and they look for answers, they have the advantage that things they have not seen too much, they are not biased. And the bias is, it can be a serious limitation for many geologists, especially for the ones with a lot of experience. Well, different geologists always has different points of view, the way they see things, the way they interpret things. It's a combination of people with some experience, we have seen certain other things, but still we go back to the basics. And the basics is that we all need to see the rocks and we all need to see understand the paragenesis, understand what are the conditions that make certain areas very high grade copper in contrast to areas that have lower copper grades. So how did you change this expression mindset of giving Kiruna as an iron only district? You started looking at copper in a different way in the general mining district. So what was different about your approach? Well, there were, there were many, many observations and facts that were good indication that the system is what it is, that how you can manage to get high grade copper along certain layers. That is a very efficient process. And although we did not try to find to understand why this efficiency was from the beginning, we could see that in the district scale there were many areas with rock packages where the copper content was deployed in terms of a basaltic rock where copper content is below the detection limit. So things have happened at that scale, in a district scale. And that when we look and combine with historic reports, the possibility that the Viscaria Kiruna district could have involved highly saline fluids in the transport of metals. Then basically we started to see the big picture. And I think for exploration we need, this is very important to keep a holistic big picture of what is going on. What do we have in the Viscaria statigraphy? But how it compares with the things that our neighbor in the Kiruna iron they have and what are the proportions of the different metals and minerals that procure along these more than two kilometers and a half mineralized statigraphy that is only way from Viscaria into the rocks that host the iron appetite deposits. That was the trigger to make us looking into new boundaries, pay attention to our satellite showings. Review historic drill core that was kept in the archives in the Mallow core storage and try to understand all these little pieces in terms of a holistic approach. And that is obviously not only a work that has to be done with the rocks, but it comes in the same manner when we treat the geophysical datasets and the eochemical datasets. So a holistic approach when we are entering a district, it is important. So we could see the scale and the signature of the system. To be honest as geologists, I still have not seen the boundaries of the alteration system. It's a big alteration system. It runs for more than seven kilometers at least. So what observations made you realize that system was not a VMS but might be something different? Well yeah, I would prefer not to talk about too much about models, but there are facts that we see in the mineralization. And to try to recognize this, we need to see through the deformation, through the metamorphism. Fortunately in the Viscaria area, the Viscaria Kiruna block and metamorphism is a much lower grain than the rest of the areas in northern Sweden. So that's a plus. But importantly also is to recognize certain facts like epigenetic, style, vein. This type of indications that can tell us that the system has been active after strata was consolidated. The system was active. Once the strata has been slightly tilted, although we didn't know and we still don't know the absolute age of the Viscaria mineralization. We could infer several things from the geometry of the alteration system. As a summary, Viscaria is a high-temperature system where copper sulfates occur together with calcacylicates and amphiboles and minerals that form at high-temperature. But the alteration of the system is strongly influenced by the hostile composition, by the primary hostile composition. Plus, classic additions of iron and sodium, we call it iron metasomatism, sodium metasomatism, that we see in several other districts in the world, especially in the Brasilia and the Kilean Peruvian examples where we have iron ore connected to copper iron ore. But one peculiarity of Viscaria, I would say, in this type of high-temperature epigenetic system that many people would tend to describe as IOCE type of systems, although Viscaria does not contain much gold, smelly copper iron. But one of the key features is that the abundance of carbonaceous material in the Viscaria statigraphy, and the carbonaceous material was altered, decomposed bleach, ending up in, as we know, in many places liberating hydrocarbons, producing CO2, forming carbonates. And all these things are very important elements for trapping the copper, because copper is a very sensitive copper solubilities. They drop very quickly if we rise the pH, which will change the rail exploitation. So, more important than temperature, that it is also one part of the game, is that the Viscaria statigraphy offer a very interesting railroads pH trap situations along the permeable parts of the statigraphy. And I think that is one of the bases for our exploration concepts at the moment. Yeah, this is a great point, and the name of the podcast series is discovered to recovery, and I will have two questions with respect to discovery and recovery. The first one, about the discovery is that, can you follow those reducing boundaries or units throughout the Kirno mining district, and then with that, you know now about the mineralization, how will that impact recovery? No, that's a very interesting question. I'm very keen to give you some hints on that, but coming back to the discovery question, how do we map these important boundaries, or these important regions where redox potential makes a clear change for the metal deposition? So, basically, people are used to see that a redox boundary, we need to see black rocks, carbonacious rocks, a lot of graphite to say, yes, there's a more reduced environment. But many of these redox boundaries are not only seen in terms of the presence of carbonacious material. One of the main things in the Viscaria area is that the iron, iron is an element that can be formed in reduced and oxidized conditions, and if we pay attention to the minerals that contain iron, especially in Viscaria, or all the ways through the through the statigraphic section from Viscaria to Kiruna, we will see that iron accommodates to these changes all the way from, they say, areas where we have iron plus 3, that's epidote, together with pi-ride and high-ride, and then next to it, then we see iron plus 2 with biotide and pyrrothide. These drastic changes in the mineralogy, hand by hand, every drill core, it helps us to map these redox liations. There are still many unknown things about the redox boundaries. We don't know if the redox is something that has worked over the time, or the solutions that carry copper that were originally oxidized were affected by the buffering, the reducing rock formations, and finally they could have regained their status of oxidizing. But similar examples happen in the Kiruna statigraphy, in the Kiruna vare statigraphy, where there are zones where more manetite and other zones higher up in the statigraphy, where there is more predominance of hematite, so more oxidized parts of the iron face, and all these things, if we understand Viscaria as a whole, Viscaria Kiruna district, 3 km of strata, how certain distribution of volatile elements occurred? We could start seeing where were the buttons and where were the tops of this system, when the copper mineralization formed. Regarding recovery, we have 12.5 million tons of tailings coming from the historic auto-cum-poo production. At that time, they mined head grades of 2.5% copper, or you could guess, that the copper contents and the tailings were quite high, and we have drilled and made a resource calculation on the tailings. It is about 0.3% copper on the tailings these days. But the flotation, it was performed in that time, it was quite efficient. They managed to recover quite high amount of copper, regardless that some of the host rocks contain black shades and fine-grained hard rocks. And we are very aware of that, but we are convinced that understanding the rock, the host rocks of the different old valleys in Viscaria, it will give us a better control, it will make us prepare to make a more efficient processing and recovery of copper sulfides. IOC deposits are unique systems, where the host rock obviously influences a lot on the recoveries, it influences on the strategies for combination and flotation. And the thing is, the geologists, we have been aware of these facts and these occurrences, and I think that we not gonna find so many problems in this part. So how do you approach your rock now? Well, in Viscaria, our aim is to reopen this amazing copper mine, and to keep a steady production but by knowing the system, we want to be more ambitious, to understand early on how far this system could go, so we could plan ahead and do things the right way. Obviously, there is always these contradictions between what an exploration geologist we like to do, is that we want to keep exploring and finding more resources and things, but we want to open a mine, and for the mine, yes, it's good to explore, but there is another important work that needs to be done. We need to de-risk the project, we need to make the resources, we need to upgrade the resources, we need to get in fair resources to indicate the resources, indicate the resources to measure the resources. That is a time-consuming effort. How we manage with the variability in host rocks, how do we manage with areas that might be more fractured, more we focus on obtaining these answers, the less risky, the less surprises we'll come during my production. I'm pretty much of our drilling in the last years, has been focused to the risk this purpose and knowledge. Obviously, at the same time, we still, we don't know where the system ends, and that is a very good sign for a mine, in terms of a long, sustainable, or increased production in the future, because at the end of the day, the tools and the great is what will dictate the life of the mine. With the recent exploration sequences by Copperstone Resources and for other companies who are operating or exploring Kiruna mining district, how do you see the future of Kiruna in terms of copper exploration and copper mining? I would say if we look in a much broader perspective. We have seen other companies looking into this historic copper showings proximal to iron ore, and that's good, because the viscaria story is sparkling the new attitude towards many of these possibly underestimated historic copper resources that are kind of connected proximal to iron ore. Let's don't forget that, especially in Norbotten, in northern Sweden, is a world-class iron province. There are two very big mines and some other smaller size iron producers in the region. But if we look carefully, there are some copper mines nearby too, historic and some in production. So, I would say more than just Kiruna, Kiruna is a well-established mining jurisdiction, but Norbotten itself, when we start looking at 300 kilometers in the district. There is the Jalibari province, where Malberget and Itec sit. Again, this is an iron ore and a copper gold system nearby. We have the operating counties iron on the border near Finland. So, all this trend is dotted with existing opaz iron producers. That contain copper shawings, hostiting mannedite or hematite in the surroundings. So, I think it's understanding the settings and the preservation of all these systems is going to be important, and not saying that all of this might render a nice discovery. But it's something that I think it has the spark of the efforts and vision that we have put in the viscaria era. Many things to less the logo and Marcel Loimania for sharing your stories, insights and knowledge. As always, a big shout out to our listeners. We always appreciate you. And thanks again to our seasoned sponsor, Angola Meruken. I'm Korakash Vichan, your host and producer for this week's episode. It was very nice to be here, but now I'm taking a break. But next week, Halakhi will be hosting a very influential episode on families and career breaks from exploration and mining. This episode was produced by your host, Anne and Thompson, with support from our production team, Halakhi Will, Brit Blumel and Maxwell Porter. Our team music is conference by Eastwinds. You can check them out at eastwinds.bandcamp.com. See you next week.