Good weather around the mine helped yesterday’s efforts, when the team wearing breathing apparatus actually travelled further than expected, reaching 300 metres.
With a low pressure weather system around the mine, coal actually exuded more methane, which in turn increased pressure inside the mine and slowed down the entry of oxygen.
The gas levels need to be monitored again this morning before re-entry. The breathing apparatus only allows the personnel to be underground for two hours at a time.
A second team, which brought gas-monitoring equipment, entered the mine at 2.20pm yesterday and started dismantling an internal coal-conveyor belt.
The first team then re-entered at about 5pm and started taking in equipment which would be used to erect a temporary seal about 170m inside.
Two-hourly relays of teams would continue today, as long as gas levels permitted, and over the next five days, mines rescue general manager Trevor Watts told The Press.
A feasibility study for a staged re-entry of the mine, progressing 100m at a time up to the rockfall which was about 2.3 kilometres along the mine's tunnel, still needs to be completed.
The bodies of the 29 miners trapped in the mine were in the main part of the mine, beyond where the rockfall occurred, making their recovery more problematic.
Watts told The Press that the gases in the mine would be monitored for about a week before work would start to place two sets of double-steel doors at the entrance, a project which should be finished by the end of July.