The Previous Mineral Resource Estimate reported in accordance with JORC (2012) for the Ongombo project was conducted by Red Bush Geoservices with the effective date of 30th September 2021. The estimate comprised 10.4 million tonnes of Indicated Resources at 1.4% Cu, 0.35 g/t Au and 7 g/t Ag, and 1.65 million tonnes of Inferred at 1.65 % Cu, 0.35 g/t Au and 7.3 g/t Ag. This updated estimate represents an increase of approximately 100,000 tonnes of contained Cu and an additional 84,000 oz of Au over all Resource classifications.

Key differences accounting for the variation in the estimates are described as follows. Red Bush considered the minimum mining height as 1.05 m. AMS considers this mining height is not realistic in modern mining scenarios. AMS diluted the model to minimum 1.6 m mining height, therefore the tonnage reported by AMS is higher and the grades lower.

Red Bush reported the resource at cut-off grade of 1% Cu, which in AMS opinion excludes the material with a reasonable prospect of economic extraction in between 0.5% and 1% Cu. Moreover, Red Bush reports Au and Ag, however no Au and Ag credits were considered for cut-off calculation and reporting. Reviewing of Red Bush estimate indicates that a number of samples with values 0 g/t were used where no Au assay was recorded for that sample.

Due to this, AMS is of the opinion that Au is underreported in the Red Bush MRE. AMS prevented Au grades from over smearing into areas of no assay by use of smaller search radii, leaving some blocks in the model non-estimated for Au. In AMS' opinion due to data spacing and reliance on historic drilling the proportion of Indicated resource in East/Ost Shoots is not warranted.