Two miners were killed and five seriously injured on Wednesday in two separate accidents, the National Union of Mineworkers said.

A worker was killed, while another remained trapped 3000 metres below the surface, at Gold Fields' Driefontein mine near Carletonville, west of Johannesburg, union spokesperson Lesiba Seshoka said.

Four other miners were seriously injured. The accident happened following two "seismic events" at the number five shaft.

The mine was served with a section 54 notice, to stop all operations, by the department of minerals and energy after the incident.

The first "seismic event" measured 2.4 on the Richter scale and occurred at 1.17pm, followed by a second one measuring 1.0 at 1.55pm, said company spokesperson Daniel Thole.

The second miner was killed in an explosion at the Extra Dimensions mine in Brits, North West at 3pm, shop steward William Mataboge said.

"The miner was drilling on a misfire and there was a blast. Another miner was critically injured. He was taken to hospital."

Work at the mine was stopped pending an investigation by a mine inspector on Friday. A company spokesperson was not immediately available for comment.

Sapa