News of the supply disruption has boosted an already strong zinc price to multi-year highs.
VZI said 10 people were trapped at the bottom of the South Pit at Gamsberg following a geotechnical failure in the early hours of Tuesday.
Eight had been safely rescued, the company said yesterday.
"We are doing everything possible to safely rescue the two remaining trapped colleagues," business head Laxman Shekhawat said.
The Department of Mineral Resources and Energy had been informed, and DMRE mines inspectors had joined management and union representatives for an in-loco inspection.
VZI said all mining-related activities at Gamsberg had been suspended.
The mine, which was inaugurated in February 2019, was said to produce 400,000 tonnes of ore per month.
VZI - part of Anil Agarwal's Vedanta Resources - said it owned 69.6% of Gamsberg, Exxaro Resources 24.4% and the Employee Share Ownership Plan held 6%.
Vedanta delisted from the London Stock Exchange two years ago.
The zinc price for delivery in three months, which was already benefitting from the strong steel story and a firm onshore rebar market, rallied to a multi-year high yesterday morning of US$2,770 per tonne, Marex Spectron's Alastair Munro said.
It's a gain of about $1,000/t since March during the COVID-19 induced market slump.