Great Dyke in Zimbabwe
At Zimplats exploration efforts have been focused on preparing for the development of Portal 5 as a replacement portal with drilling carried out to determine the location of the box cut and to verify the ground conditions along the declines and at major infrastructure points. There was also infill drilling to assist with the understanding of the local features affecting mining and the low angle shear in Bimha Mine in particular. At Mimosa exploration work was carried out on the western limb of the South Hill ore body to investigate perceived low grades in the area as well as drilling for fault investigation on the northern section of the mine close to the ore body limit. Exploration drilling was also carried out to upgrade the Far South Hill ore body to the measured and indicated resource categories.
Implats’ main geographic focus offshore was Canada where, in conjunction with HTX Minerals and Northern Shield Resources, Implats continued to explore for PGMs in the Mid-Continental Rift area around Thunder Bay and the Labrador Trough respectively.
In the Labrador Trough in northern Quebec, Northern Shield Resources carried out a 14 borehole and 1 501 metre drill programme at the Idefix Property to test areas of surface mineralisation (up to 16.2g/t Pt + Pd + Au over 1 metre in sawn channel samples) found the previous year. A 31.4 metre channel sampling averaging 1.4g/t PGE + Au was taken to the south of the previously discovered mineralised areas. Unfortunately drill assays from all areas were disappointing, with grades ranging from 0.26 to 0.4g/t Pt + Pd + Au over the 14 – 20 metres. Implats has withdrawn from the project.
Implats and HTX Minerals, a subsidiary of Transition Metals Corp., completed the agreed work programme on the prospective Mid-Continental Rift rocks in north west Ontario. Implats and HTX formed a 75:25 joint venture on the most promising project at Sunday Lake west of Thunder Bay. Here a prominent reversely polarised feature was thought to be due to a prospective early rift intrusion. Two drill programmes totalling 11 boreholes and 5 095m intersected PGM mineralisation at the northern margins of the anomaly. Best intersections, though not of true width include:
- 3.22g/t PGMs, 0.26% Cu & 0.11% Ni over 20.2m including 5.37g/t PGMs, 0.45% Cu & 0.13% Ni over 3.0m
- Semi-massive sulphide veins along the basal contact with up to 7.82g/t PGMs, 1.98% Cu & 1.10% Ni
- 2.84g/t PGMs over 15m including 9.75 g/t PGMs over 1m
- The mineralisation has high Pt:Pd ratios, which are typically >1:1.
The mineralisation is associated with a buried Proterozoic aged mafic to ultramafic intrusive complex interpreted to be at least 3.5 kilometres in diameter. To date, only the northern portion of the intrusive complex has been tested by drilling, with all boreholes that intersected the intrusion encountering elevated PGMs. Follow-up work is envisaged for FY2015.
Elsewhere Implats continues to monitor exploration developments worldwide and review numerous exploration and potential mining opportunities.