Located in the central area of the country, the Bergslagen district is home to some world-class metal mines like Garpenberg, Zinkgruvan, and Falun. But despite its long history of mining, Sweden is still off the radar of many international investors. The country is Europe’s leading mining nation, accounting for 91% of the continent’s iron ore, 9% of the copper, and 24-39% of its lead, zinc, silver, and gold.
Sweden’s Boliden, which owns Garpenberg, is its largest mining company, but the country is also home to projects being explored by Lundin Mining and Agnico Eagle Mines. That said, international investment in exploration is still extremely limited – deterred by the notion of high taxes, an active environmental movement, and elevated labour costs.
Vancouver-based District is hoping to change that perception with its Tomtebo property, an advanced exploration project that covers an area of 5,144 hectares around 175 kilometers (km) northwest from Stockholm, Sweden’s capital. Thanks to the district’s long history of mining, infrastructure like roads, railway, and power lines surround the project. Boliden’s Garpenberg, which was once referred to as the world’s most productive underground zinc mine, is 25km south of Tomtebo. District Metals sees a number of geological similarities between Garpenberg and Tomtebo, from host rocks, structure, alteration, and mineralization styles. Historic production at Tomtebo comprised 120,000 tonnes at 4.4% copper intermittently for over 200 years, but the area has seen little to no exploration in the intervening period. In 2018, former owner EMX Royalties Corp assayed eight rock grab samples from dump piles that ranged from 0.2% to 3% copper, 0.1 to 2.5 grams per ton (g/t) gold, 0.1 to 20.1% zinc, 0.1% to 10.8% lead, and 3.1 to 383 g/t silver. Today, District Metals is looking to apply modern systemic exploration techniques at Tomtebo in an effort to unlock the property’s potential – and put an under-the-radar mining district on the international map.
Since acquiring the project from EMX in February 2020, District Metals has been busy assembling the pieces to start its aggressive exploration campaign at Tomtebo.
In July 2020, the firm began an airborne electromagnetic and magnetic survey at Tomtebo – the first time a deep penetrating airborne study has been carried out at the site. The survey covered the entire Tomtebo property with around 600 line-kilometers at a line spacing of 100 metres (m) and detecting conductive polymetallic sulphide mineralization at depths of 500m or more.
On March 15, 2021, after months of preparation and armed with nearly $5 million raised in a private placement, the company finally started drilling with a 5,000m, 21-hole program targeting four zones — Oscarsgruvan, Steffenburgs, Gårdsgruvans, and Gamla Gruvans.
Two weeks later, District Metals announced that a ground survey revealed numerous gravity high anomalies on the property. The anomalies were located at the historic Tomtebo mine, both within and outside of the known mineralized zones, confirming the mineralized domains that offer “immense expansion potential.”
The gravity high anomalies at the mine reveal an exploration target of over 72 million tons (Mt) at a density of 3.5 grams per square centimetre (g/cm3) from near-surface down to a depth of 650m.
Another significant blind gravity high anomaly was identified 1 km northeast along trend from the historic Tomtebo mine that is open to the northeast and at depth where an exploration target of 34Mt at a density of 3.5 g/cm3 was modeled at shallow depths. Yet another anomaly was identified 600m southwest of the mine that is associated with historic iron sulphide occurrences, which are known to sometimes coalesce with polymetallic sulphide mineralization in the Bergslagen Mining District. In April, after drilling 1,377m in seven holes, the company sent drill core samples from three holes for analysis. It expects the results to arrive by late May.
On the personnel front, the company recently appointed Marlis Yassin as its new chief financial officer, taking over from Gavin Cooper who had been in the role since 2017. Cooper will continue to work with District Metals as a consultant. Yassin has over 15 years’ experience working with companies in various sectors, including mining, technology, and industrial products.
District Metals also named Hein Raat as its country manager for Sweden in the run-up to the Tomtebo drilling program. Raat is a professional geologist (EurGeol) with extensive experience exploring for base and precious metal deposits in Scandinavia and Europe. He was a geologist for the Boliden Group in Sweden for eight years, with the last four years being focused on polymetallic projects in the Bergslagen district. In addition, Rodney Allen, who did his PhD in volcanic resources, has been appointed as a technical advisor to the company. He was manager of Geology Research and Development for the Boliden Group in Sweden for 10 years.
“We are very pleased with the progression of our maiden drill program at Tomtebo,” District Metals CEO Garrett Ainsworth said in a recent statement.
“Our technical team and drill crew in the field are firing on all cylinders, which has resulted in optimized production from the drill rig with best practices being carried out with regards to health, safety, and the environment,” he added.