ANATOMY OF A DULUTH COMPLEX CU-NI-PGE MINERALIZED SYSTEM: THE SOUTH KAWISHIWI INTRUSION

The 270 km² South Kawishiwi intrusion (SKI) is one of several large troctolitic intrusions at the base of the Duluth Complex that contains world-class Cu-Ni-PGE ore deposits. These deposits include, from southwest to northeast, the Serpentine, Birch Lake, Maturi SW, Maturi, and the Spruce Road deposits that collectively contain 4.88 billion metric tons of Ni 43-101 categorized mineral resources. Compilation of all historic and recent drilling (2,300,000 feet of drilling in 1746 holes) and the completion of 1:500 scale bedrock geologic mapping (21,000 outcrops mapped) have led to a new fundamental understanding of the anatomy of this Cu-Ni-PGE mineralized system.

 The most critical part of this analysis was the tenet that analyzing and understanding magmatic processes and ore development must begin with a clear and concise knowledge of the nature of the system at the outset: when it all began! Such knowledge includes the determination of the composition and crystallinity of the magma, the timing of sulfide saturation and modes of delivery of magma injections, the geometry of the magmatic plumbing system, and the identification of the geometry and composition of the footwall, hangingwall, and sidewall rocks.