The Voyageur lands cover a diverse assemblage of Proterozoic sedimentary and volcanic rocks that have the potential to host a variety of mineral deposit types, including magmatic nickel, copper, PGM, and orogenic gold. Despite the extensive history of copper and iron mining in the western Upper Peninsula of Michigan, the Voyageur Lands are at a relatively early stage of exploration.
Within the Voyageur lands, Bitterroot and Altius have identified significant potential for PGM mineralization in the 35 square-kilometre Echo Lake layered mafic intrusion. In 1997, Bitterroot drilled 3,270 meters in five core holes at Echo Lake. Drill hole EL-97-03 intersected ten flat-lying anomalous PGM-bearing horizons within the intrusion, with the highest-grade interval containing 1.01 grams Pt+Pd+Au/tonne over 5.42 metres (17.8 feet), within a 21.3 metre (69.8 feet) interval grading 0.52 grams Pt+Pd+Au/tonne. The Echo Lake intrusion has potential to host additional reef-type PGE mineralization along strike from the currently known mineralized zones and Ni-Cu-PGE mineralization along its contacts or within satellite intrusions and feeder dykes.
Lundin Mining's Eagle nickel/copper/PGM deposit is located in a Keweenanwan-aged (~1.1 billion year-old) mafic intrusion in the Paleoproterozoic (~1.85 billion year-old) Michigamme Formation. This geological setting also occurs under much of Bitterroot's Voyageur Lands.
In October 2015, Altius retained Geotech Ltd. to complete a 4,590 line-kilometre VTEM Plus airborne magnetic and electromagnetic survey. In early 2016, Altius' analysis of the VTEM Plus data and subsequent Maxwell modelling has resulted in the selection of ten high-priority targets and six secondary targets for follow-up. Prospecting around the VTEM Plus targets has identified an ultramafic high-level intrusion or flow, which enhances the exploration potential of several adjacent, high-priority VTEM Plus targets. Altius is in discussions with potential sources of funding for follow-up ground geophysics and drilling to test these targets.