Duluth Metals has revealed an exploration update for East Shore, which is part of its 40,000 acres of 100%-owned exploration properties in the Duluth Complex, north-east Minnesota.
According to the company, a recent four-hole shallow drill programme at hole 14-DM-052 returned 11.8ft of 1.993 total precious metals (TPM) with 0.505% copper and 0.172% nickel, and hole 14-DM-049 returned 11.3ft of 1.794 TPM with 0.399% copper and 0.121% nickel.
The company geologists discovered a zone of palladium-platinum in the eastern marginal zone of the South Kawishiwi Intrusion (SKI) on the Duluth Complex in 2012.
Duluth Metals president Vern Baker said: "The geologic model developed from the consistent pattern of finding platinum group metals (PGM)-rich anorthositic rocks just to the east of a xenolithic contact zone between the troctolite of the SKI and the anorthositic series (AN-Series)."
In February 2013, the company identified two new mineralised areas on exploration lands.
The mineralisation along the contact between the AN-series and the SKI, south of Bogberry Lake included fine to medium-grained chalcopyrite, pyrrhotite and platinum group element (PGE)-bearing minerals.
Outcrop sampling results from sulphide-rich gabbroic anorthosite of the AN-series yielded up to 3.54g per tonne TPM and float sampling up to 7.74g per tonne TPM.
Two drill holes intersected the mineralised zone at depth, of which 12-DM-007 returned an 11.7ft intersection of 3.28g per tonne TPM, and 12-DM-006 returned a 13.9ft intersection of 1.63g TPM.
During the 2013 field season, the company focused on further delineating the mineralised zone and investigated a curvilinear magnetic lineament and the SKI/AN-series contact between Bogberry and Heart Lake, for PGE potential.
Large outcrop samples of between 1kg and 5kg at the zone yielded up to 2.03g per tonne TPM, while grab samples from outcrops contained up to 1.64g tonne TPM.
According to the company, a consistent ~2:1 ratio of paladium to platinum is observed for most outcrop and boulder samples, while copper contents are typically low at about 0.08% to 0.33%.
Drill sections for holes 14-DM-049 and 14-DM-050, and for holes 14-DM-051 and 14-DM-052, demonstrate that the mapped surface PGE-enriched mineralisation of the margin of the AN-series, where the presence of magnetic basalt and sandstone xenoliths occur, has continuity at depth.
The mineralised zone ranges from 1.0g per tonne to 5.0g per tonne TPM, and is currently defined along 1.2km strike length and extends down dip to a known depth of 200ft.
The mineralisation occurs along the contact between the SKI and AN-series gabbroic anorthosites, while the hanging wall troctolite contains numerous oxide-rich magnetic xenoliths.
The spatial relationship between the magnetic xenoliths and mineralisation suggests PGE-prospectivity could extend an additional 1.5km to the north-west along a curvilinear magnetic lineament defined by these oxide-rich xenoliths.
The xenoliths consist of dark grey, fine-grained, non-magnetic to magnetic basalt from the North Shore volcanic group, and a light brownish-grey, banded, granular, plagioclase-magnetite-rich rock interpreted to belong to the Colvin Creek meta-sedimentary package.
Image: Bedrock geology, geochemical sample and drill hole location map. Photo: courtesy of CNW Group/Duluth Metals.