Hundreds of workers threw stones and 'loaded' snowballs at police officers in from of the JSW HQ after government talks reached a stalemate.
Police only managed to gain control of the mob which gathered in front of the main building of miner Jastrzębska Spółka Węglowa (JSW) in the early hours of Wednesday, after being pelted by stones, and snowballs packed with screws.
The authorities reacted by shooting rubber bullets into the crowd, injuring at least one protester.
TVN news channel quoted JSW spokesperson Katarzyna Jabłońska-Bajer as saying that the workers were probably joined by right-wing activists and hooligans, who shouted “Thieves. Thieves” at the police.
Around a dozen protesters, aged between 20 and 30, were detained.
JSW miners are protesting the company's decision to cut costs as a reaction to the worsening situation in the Polish coal industry.
The plan includes such measures as a freezing of wages in 2015, as well as the removal of bonuses for workers.
Members of the JSW board met with government representatives Tuesday to discuss these issues, but no deal has been struck.
Discussions will be continued on Wednesday afternoon.