This week I spoke to Garrett Ainsworth (CEO & President) of District Metals (TSXV:DMX, FRA:DFPP) about their Tomtebo property, located in the Bergslagen Mining District in South Central Sweden (Figure 1). District have only recently taken the reins of Tomtebo but are in advanced stages of exploration thanks to a wealth of historic data obtained from, and this is a new one to me, an archive.
The appeal to take on Tomtebo was multi-faceted. Garrett emphasises the great size and scale potential of mineralisation in the Bergslagen district, which is incomparable to other districts around the world, and the silver-rich nature of the VMS mineralisation. Grades and tonnages are outstanding on a global scale, and the district is host to thousands of mineral occurrences of varying types as well as a number of producing mines. On top of this, exploration licenses in Sweden were all state-owned and operated until the 1990s which means today there remains a lot of underexplored, highly prospective land. Another key aspect of the appeal of Tomtebo was its location in Sweden; a top tier mining jurisdiction with a vested interest in supporting the industry.
The 5,144 ha property is host to polymetallic (Zn-Cu-Pb-Au-Ag) VMS/SedEX mineralisation, for which the geological potential is rife. Tomtebo is intersected by the same regional NE-SW trend associated with deposits elsewhere and intense footwall alteration to a phlogopite/biotite-cordierite-garnet assemblage with high copper is suggestive of a productive hydrothermal system active in the geologic past. Observed VMS and replacement-style mineralisation forms lenses or pods of massive sulphide mineralisation present for an impressive >17km strike length. Drill intersects of these lenses (Figure 2) show just how mineralised Tomtebo is.
Further, Tomtebo shows geological similarity to the producing Garpenberg Mine (Boliden, 25km SE of Tomtebo), which is cited as the most productive underground zinc mine in the world. In addition to already high tonnages and grades, mineral resources remain open at depth at Garpenberg and exploration drilling throughout production has significantly increased known resources. This represents the huge potential for Tomtebo.
The property had seen no modern systematic exploration prior to District’s acquisition earlier this year. Historic data includes drill assays with few elements, some grab sampling (Table 1; EMX Royalties Corp) and some partial airborne geophysics. Compared to other projects going to drilling in the near future, this is not a lot of data. Yet District are already planning to begin drilling in Q1 2021. So how did they advance so quickly?
|Au||0.07 - 2.45 g/t|
|Ag||3.1 - 383.0 g/t|
|Cu||0.16 - 2.97 %|
|Pb||0.04 - 10.8 %|
|Zn||0.09 - 20.1 %|
Utilising historic data and the results of their recent airborne magnetic and electromagnetic surveys, with some 3D modelling and geology brains, District have been able to generate drill targets. They plan to re-drill old holes and assay with a much more comprehensive element suite than the existing assays. In addition to this their current field program, involving geological mapping, prospecting, and geochemical sampling, will provide a property-wide and detailed understanding of the area’s geology and mineralisation (Figure 3).
Sweden is one of the highest ranked countries for investment attractiveness with a long mining history, and several big players operate there. Which makes sense when you hear that Sweden supplies 91% of Europe’s iron ore, 9% of the copper and up to 29% of the continent’s lead, zinc, silver, and gold. This makes Sweden incredibly attractive to not just mining & exploration companies, but to the investor as well. Sweden also boasts an excellent infrastructure network including rail and road access, deep water ports, and five smelters in the Nordic region. A good infrastructure means overall costs are going to be lowered, should Tomtebo get out of the ground.
I’m looking forward to hearing the results of their current field program, and to watch how Tomtebo progresses over the next year as District move to drilling and hopefully beyond. For now, go and take a look at the historic drill data (See below), there is more than enough there to convince you of the potential of this project if you aren’t already*.
*which I think you should be
All information in the above article is taken from the District Metals website and all materials contained within, as well as personal communications with Garrett Ainsworth (CEO & President).
 and corporate presentation - https://www.districtmetals.com/_resources/presentations/presentation.pdf
The Tomtebo Property:
Historic Drill Results: