In a presentation at the Africa Down Under conference in Australia, managing director Errol Smart said the significant infrastructure is in place, with detailed engineering assessments having confirmed the main hoisting shaft's integrity and metallurgical validation and optimisation work underway.
In addition, the primary shafts and underground decline roadways are in place to allow access to the deepest remaining targets, and pre-existing solar power links are online.
The upcoming opening of Prieska is actually a reopening; the operation was idled in 1991, after 20 years in production, for financial reasons. Orion has a 73.3% interest in Prieska, as well as the sister Marydale project.
Updated mine construction work at Prieska should begin by the second half of 2019 and continue through the majority of 2020 ahead of a start late that year.
The mine's JORC resource estimate is 28.4 million tonnes, including 1.12Mt zinc (3.8% average grade) and 365,000t copper (1.2% grade).