The Great Dyke
The Great Dyke, which hosts the Main Sulphide Zone ('MSZ') is an elongated, slightly sinuous, 550 km long, layered igneous intrusion, with a width of 4 – 11 km, in central Zimbabwe. The Great Dyke bisects the country in a north-north-east orientation and is a 2.5-billion-year-old layered igneous intrusion comprising igneous rocks ranging in composition from ultramafic to mafic.
The project area is located on both the eastern and western flanks of the Great Dyke. There is no outcrop as the mafic and ultramafic rocks weather easily to a black cotton soil. The area is underlain by both the mafic and ultramafic sequences dipping at 20° to the east on the western side of the Great Dyke and 32° to the west on the eastern side of the Great Dyke. The MSZ is estimated to be approximately 700 m deep in the southern end of the tenement, up to 1 000 m deep in the centre, and 600 m deep in the northern end of the tenement.
An aero-geophysical survey was flown to identify the chromitite and pyroxenite layers that may contain minerals of interest. The high resolution magnetic and gamma-ray radiometric data sets allow the geophysical exploration strategy to interpret the magnetic and radiometric data to add to the knowledge on the lithology's present and geological structures visible and determine if they can be correlated with the known target mineral occurrences. The topographic surface of the tenement area was also obtained from the survey.
The initial exploration programme comprising some 238 diamond core boreholes totalling 32 483 m, which took place from November 2018 to April 2019. This programme was followed by a second phase of drilling comprising 77 diamond core holes totalling 7 642 m. The second phase of drilling was completed in December 2020. The programmes generated over 22 000 samples that were assayed by an independent laboratory. The total number of drill holes completed were 315.
The drilling programme was undertaken in five areas KPNE, KPE and KPSE, KPW and KPS. The figure alongside depicts the location of the drill holes for the two phases of exploration.
Subsequent to the two exploration campaigns, the gap between KPE and KPSE was explored; this phase consisted of 16 drill holes over the 4 km strike. The drilling has been concluded and the samples have been sent to the independent laboratory. These results have not been included in the resource estimate. Advance drilling ahead of the mine development has been allowed for in the capital estimate.
