While recovery of the mine and equipment are well underway, operations have been hampered by more heavy rain over the weekend (February 2-3) which has further submerged parts of internal haul roads and the mine access road, which was extensively damaged in last month's flooding, Ensham Resources said.
Ensham was hardest hit of the Central Queensland coal mines, many of which experienced flooding into pits from cloudbursts and local runoff.
Ensham was severely flooded when unprecedented flood flows into the Nogoa River broke through levee banks, submerging two of the mine's six coal pits and one of its four draglines which remains stranded in about 15m of floodwater.
Ensham CEO John Pegler said the company was working with government authorities, such as the Environmental Protection Authority, to facilitate the rapid return of the trapped river water to the Nogoa River.
The Nogoa River at Emerald was still experiencing flood flows from continued local rain and flood releases from Fairbairn Dam as storms continued to gather this week.
Pegler said Ensham was hopeful of resuming about 70% of normal production within weeks and hopes to have the remaining pits accessible by year-end.
He said the three operational draglines and several truck and shovel fleets had returned to normal overburden removal operations in the four accessible pits.
One new pit was being opened by the massive new 7000-tonne Bucyrus 8750-63 dragline which was commissioned a year ago.
Pegler said the mine would be gradually de-watered in three stages using a combination of natural drainage, "high flow" and "high head" pumps over a period of months.
Pegler said he was confident of the rapid recovery and restoration of the trapped dragline which he hoped would be back in operation by year-end.
On Wednesday Queensland Minister for Mines and Energy Geoffrey Wilson and Department of Mines and Energy Director General Dan Hunt visited the mine.