South Africa's department of mineral resources says plans are underway to free a large number of miners caught underground by hoisting them up an adjoining shaft.

The department says it has an inspector monitoring the situation at the Thembelani shaft in Rustenberg run by mining company Sibanye-Stillwater.

The company says some 1,800 miners are affected but are safe with no serious injuries. It says some rails that were being transported underground came loose and fell down the shaft midday Tuesday, and workers are removing them and inspecting the shaft for any damage.

The company confirms the adjacent shaft will be used if needed.

The Associated of Mineworkers and Construction is expressing its concern.