Preliminary results at the Royal Sheba project indicate there is a world-class orebody below current workings that, if it were in any Northern American jurisdiction, would justify a separate company listing to invest in the mining operation. We estimate there is an 18-year life of mine here, based on a steady-state production rate of 25 000 t/year, using modern mechanised mining equipment.
At Sheba Mine, we are currently mining the Thomas and Verster orebodies. Previous mining at Sheba only took place in the high-grade sections, which has left a million ounces of lower grade ore in the ground at Royal Sheba. While the grade here is lower than in the rest of Barberton Mines, by employing smart mining techniques, including mine mechanisation, and upgrading our existing processing capacity, we are confident that we can extract it profitably.
Recent exploration drilling at Sheba Mine to locate extensions to the main orebody has intersected several high-grade sections of the reef, with channel widths of between 0.76 and 1.05 metres, grading in excess of 100 g/t of gold. In the 260 Cross fracture and the Northern limb, there is visible free gold (which refers to gold not bound up with other minerals).
We recently started to mine the down-dip mineral resource of the Zwartkoppie (ZK) orebody on 37 level and have drilled ten diamond holes to explore the body between 37 and 38 level. This showed an estimated 3 000 t at 5.2 g/t, and it has enabled us to upgrade some of the ZK orebody to the Measured and Indicated Resources category.
We also drilled two diamond holes into the shallow mineral resources in the Northern limb at Sheba Mine, at 22 level. Another eight diamond holes will be drilled into this orebody in the 2022/23 financial year.
The average grade of the first 5 000 tonnes of bulk sample ore from Royal Sheba was estimated at 0.7 g/t from the grade model, although sampling in the plant has yielded a better-than-expected head grade of 0.94 g/t and a gold recovery of 87%. The strike extent, which we have confirmed from surface, is over 850 metres.