The Sigdal Project comprises two exploration licences granted in April 2018, covering the historical nickel occurrences of Grågalten and Ramstad.
The Ramstad Ni-Cu deposit consists of minor historical mine workings over a strike length of around 1 km in a north-south direction, approximately 4 km north of the town of Prestfoss. The historical mine was operated in the years 1874-1877, and approximately 1200-1300t of nickel ore with a total amount of 7t nickel was produced.
The nickel mineralisation is hosted within a metagabbro intrusion which most probably is made up of several lenses within a granitic gneiss. The metagabbro lenses are several meters thick and some tens of meters long. The granitic gneiss is intersected by a major fracture zone. The main historical mine workings comprise a 25m long by 5-10m wide, north-south orientated open pit in a metagabbro containing disseminated mineralisation of pyrrhotite and chalcopyrite.
In 2006, Blackstone Ventures completed a ground EM survey which located a prospective conductor associated with the known sites of historical nickel production at Grågalten and Ramstad. Blackstone tested the ground EM conductor with two relatively short drill holes completed in 2006, confirming the presence of nickel mineralisation at the two historical prospects.
Drill hole ER2006-13 drilled on the north side of the historical prospects returned highly anomalous assay values for Ni, Cu and Au grades up to 10g/t at drill depths of 22 metres and 36 metres as follows:
- 22.62m – 24.10m (1.48m) @ 0.36% Ni, 0.43% Cu, 10.1g/t Au, & 2.9g/t Ag
- 35.55 – 36.00m (0.45m) @ 0.94% Ni, 0.88% Cu, 0.05g/t Au & 4.0g/t Ag
Mineralization is associated with mafic to ultra-mafic rocks intruded by granites and then complexly folded. Coarse-grained sulphide recrystallization occurred due to a high-grade metamorphic overprint during the Svecogegnian Orogeny (1600-1450 Ma). The nickel mineralization includes accumulations of nickel and copper sulphides, with the mineralisation remobilize into pods and elongate bodies of semi-massive and massive sulphides. The nickel sulphides are structurally controlled along shear zones and within tight centimetre to meter scale folds.
The geophysical conductor is coincident with the old mine workings and the mineralized horizon hosting these shallow, anomalous Ni-Cu-Au drill intersections. Based on the encouraging results from the Blackstone drilling from 2006, and considering that only two holes have been drilled to test the EM conductor with which nickel and gold mineralisation is directly associated, further drill testing of the conductor is justified to determine the thickness and extent of the mineralised horizon down-dip and along strike.