The National Union of Mineworkers (NUM) has called for “drastic action” to improve the safety standards and procedures at mines, as four mine workers are trapped and feared dead in a mine in Orkney.

Rescue teams are currently on site, but it is estimated that it will take three or four days to rescue the workers due to rocks continuing to fall underground, the NUM said in a statement.

The mine workers became trapped at the Tau Lekoa mine in Orkney after “seismic activity” on Friday afternoon.

NUM spokesperson Livhuwani Mammburu confirmed the incident, saying the seismic activity took place at 12:00 on Friday.

As a result, five mine workers were trapped, although one was rescued immediately after. He suffered serious injuries and was rushed to hospital, Mammburu said.

READ | Four mine workers trapped, feared dead in Orkney

“Earlier [on Friday] the proto team was able to communicate with the four mine workers who are still trapped underground, but later they were no longer responding,” the statement reads.

NUM president Joseph Montisetse told eNCA a team was working around the clock to rescue the trapped workers. The incident has left the union “deeply worried and concerned”, he said.

“The NUM strongly believes that it’s necessary to compel the mining industry to comply with safety standards and procedures… We call on the state to hold the industry fully accountable for its failures and adopt a no-nonsense approach when it comes to mine deaths.”