The accident occurred on Tuesday, African Rainbow Mineral Limited (ARM) and Anglo American Platinum said in a joint statement.
The two institutions were partners in the mining venture.
“Both ARM and Anglo American Platinum extend their sincerest condolences to the family, friends and colleagues of the deceased,” the companies said.
The accident occurred amid a lengthy wage strike by platinum miners which has crippled the platinum sector.
Thousands of Lonmin, Impala and Anglo American Platinum (Amplats) miners downed tools on January 23 demanding a basic monthly salary of R12,500.
They rejected the companies’ offer that would bring their cash remuneration to R12,500 by July 2017.
Scores of mineworkers — both legal and illegal — have been killed in mining accidents since the start of the year.
In one of the latest incidents, two workers from gold mining company, Gold Fields, died in separate accidents last month.
Earlier in the year, Harmony Gold in Doornkop lost nine workers in a fire that was triggered by a rockfall.
In February, at least 11 illegal miners were killed in Roodepoort, a few others died in Benoni on the East Rand, while some were killed in the Free State.