Police arrested 37 people during a protest at mining company Xstrata’s Kroondal operations in North West on Tuesday.

“The miners threw stones at the passing vehicles and burnt tyres,” said Brigadier Thulani Ngubane.

“Police were dispatched to the area to control the unruly protesters and they had to use rubber bullets and teargas to disperse the minerworkers.”

There were no injuries to the group of about 200, which barricaded the road leading to the company’s Kroondal mine, he said.

Those arrested would appear in the Rustenburg Magistrate’s Court on Thursday.

However, the National Union of Metalworkers of SA (Numsa) claimed in a statement that police used live ammunition and that there were injuries.

In a follow-up interview, Numsa spokesman Steve Nhlapo said though Numsa stood by the claim that live ammunition had been used since problems started in the area of the Kroondal mine last Thursday, it had no access to anyone who had been arrested to prove this.

This denial of access was, in itself, worrying, said Nhlapo.

Numsa called for the immediate suspension of all the police officers responsible for this “ridiculous shooting of striking workers”.

North West police said only teargas and rubber bullets had been used.

Nhlapo said workers went on strike to demand that action be taken against a “racist white employee for assaulting a fellow black worker”.

The SABC reported on Tuesday night that miner Joseph Koetje was allegedly assaulted for refusing to sign for a wage deal without the representation of the union. Numsa said that instead of taking action about the assault, the company had “opted to co-opt the police to do their dirty work”.

However, Xstrata Alloys said on Tuesday that a properly constituted hearing had been held to investigate the alleged incident which led to the strike.

“The hearing ruled that there were insufficient grounds to find the accused guilty of the alleged assault after hearing from four individual witnesses,” said the company’s communication and transformation manager Christopher Tsatsawane.

“The investigation has consequently been concluded,” he said.

Tsatsawane said the company condemned any form of violence or intimidation and would continue to work to resolve the situation peacefully with the authorities.

He said the illegal and unprotected strike was by a group of “former employees” at Xstrata’s Kroondal operation, who blocked the entrance and road to the operation on Monday and Tuesday, and intimidated Kroondal employees reporting for work.

The police had dispersed them.

Xstrata is one of the top five global producers of copper, thermal and metallurgical coal, ferrochrome, zinc and nickel, and also produces silver, lead, platinum, gold, cobalt and vanadium. It employs more than 70,000 people at more than 100 operations in more than 20 countries.