JOHANNESBURG, Feb. 1 (Xinhua) -- The South African Congress of Trade Unions (Cosatu) on Thursday said around 900 mine workers are trapped underground at the Beatrix Mine in the Northern Free State.

The Association of Mineworkers and Construction Union (AMCU) president Joseph Mathunjwa confirmed the accident. He said the power outage, reportedly due to thunderstorm, led to around 940 workers being trapped underground at shaft 2 and shaft 3. Forty workers were then rescued, leaving 900 at shaft 3 underground.

Cosatu said they want the government to investigate the cause of the tragedy. Sizwe Pamla, Cosatu national spokesperson said, "Our government needs to come to the party with some tangible enforcement mechanisms to ensure compliance with health and safety regulations and work to reduce mine accidents."

They also called for the emergency services to double their efforts to rescue the trapped miners. Cosatu also said mining companies should learn from past experiences to prevent increasing mine fatalities.

"The federation continues to be deeply concerned with the rate of mining fatalities and calls on the mining companies to take seriously the five point pledge plan that is meant to achieve zero harm with regard to mining fatalities. We need solid and sensible prevention mechanisms in place to help reduce and ultimately stop mining fatalities." Pamla said.

The Mineral Resources Minister Mosebenzi Zwane will visit the mine on Friday to understand what transpired for the miners to be trapped.