The Ultra 1 area of the Grizzly property is dominated by strata correlated with the Upper Triassic Stuhini Group. These are intruded by Middle to Late Triassic stocks and plutons of quartz diorite and diorite. In eastern portions of the property Stuhini strata is overlain by Miocene volcanic rocks of the Level Mountain Group.

In 2015, Garibaldi Resources targeted a chargeability and resistivity anomaly with 5 diamond drill holes, 3 of which (GC-15-01, GC-15-03 and GC-15-04) confirmed the source of the anomaly to be a dark black, strongly magnetic serpentinized peridotite. Correlating this unit with the size of the chargeability anomaly indicates this unit may occupy an area of at least 1 square kilometre with a minimum thickness of 200 metres and remains open to the west and south.

Hole GC-15-01 intersect equigranular quartz monzodiorite to 52.5 metres depth where andesite intersect to a depth of 68 metres where it was in fault contact with dark grey-black serpentinized peridotite. This unit was strongly sheared, fractured, and altered. It is composed of 1 to 2 millimetres rounded altered olivine and pyroxene in a dark grey black aphanitic groundmass. This unit lacks quartz veins but is dominated by 1 to 10-millimetre calcite-sericite veins, and pyrite fracture fill. Due to the strong shearing and faulting most of the pyrite has been ground into a grey gouge but is still identifiable on certain fractures. This unit is strongly magnetic. The abundance of magnetite and pyrite fracture fillings in this unit is the source of the chargeability anomaly.

Drill Hole GC-15-02, from the same pad as 01, consisted of quartz monzodiorite and diorite to the end of hole at 236 metres. The hole was reported to contain traces of visible very fine-grained disseminated chalcopyrite throughout, usually associated with weak K-feldspar alteration or epidote. Traces of chalcopyrite were also found in 1-millimetre quartz veins. Pyrite was rarer than chalcopyrite and only identified in chlorite filled fractures. Traces of very fine-grained chalcopyrite could still be identified near the bottom of the hole.

GC-15-03 was drilled from Pad 2, 200 metres south of Pad 1 and targeted a chargeability anomaly 250 metres downhole. The hole was drilled to a depth of 308 metres and confirmed the high chargeability anomaly at depth is caused by a 206-metre-thick (apparent thickness) strongly magnetic mafic unit with abundant pyrite along abundant shear surfaces. The drill first intersected a pebble to cobble polymictic matrix supported breccia from 31.0 to 70.8 metres; then fine-grained sedimentary rock and andesite occurs from 70.8 to 86.0 metres, hosting moderate quartz veins with occasional medium-grained chalcopyrite; from 86-102 metres the rock was interpreted to be the intensely altered magnetic unit with alteration dominated by intense hematite and bright orange alunite and containing 40 per cent quartz veins up to 5 centimetres with dark sulphides and pyrite along margins, but no chalcopyrite. From 102 to 308 metres dark black fine-grained strongly magnetic serpentinized peridotite was intersected. This ultramafic unit is cut by 20 to 30-centimetre-wide coarse-grained felsic dikes spaced 10 to 50 metres apart. This unit starts with a strong hematite alteration which gradually decreases within 10 metres and is cut by rare quartz veins containing black-grey fine-grained sulphides. Pyrite occurs as very fine-grained polished shear surfaces throughout the unit.

GC-15-04 was a vertical hole drilled to a depth of 180 metres to test a chargeability high. From 14.5 to 139.8 metres a succession of interbedded andesitic volcanoclastic and sandstone-siltstones were intersected. This interval contained traces of disseminated chalcopyrite and pyrite stringers. Locally up to 5 per cent disseminated chalcopyrite occurs within 3-centimetre patches. Traces of chalcopyrite and malachite were also identified in 1 millimetre’s quartz veins. This unit was consistently chlorite-sericite altered with approximately 5 to 15-millimetre quartz veins. The dark black, strongly magnetic serpentinized peridotite was intersected at 139.8 metres and continued to the end of the hole at 180 metres. This unit contains fine grained polished pyrite along shear surfaces.

Garibaldi Resources later described the area tested by holes GC-15-01, GC-15-03 and GC-15-04 as the Ultra 1 Zone. These holes had intersected the very thick, homogeneous ultramafic “black unit”, including a 206 metre section in GC-15-03, consisting of high-grade magnesium (with grades ranging from 21.7 per cent and 23.5 per cent) and elevated nickel (ranging between 0.11 per cent and 0.15 per cent); this structure is preceded by consistent, highly elevated scandium at the top of each hole including 54 metres grading 34 grams per tonne in GC-15-03 (News Release, Garibaldi Resources February 11, 2016). Tests indicate nickel is associated with sulfides. Garibaldi further reported that, 'Metallurgical testing by Bureau Veritas has confirmed that high-grade magnesium and nickel intersected in widely spaced drill holes at Grizzly Central (Ultra 1 Zone discovery) are both recoverable from the Kaketsa “black unit” (News Release, Garibaldi Resources April 26, 2016).