The key borehole to provide gas data from the mine intersected the side of a 5 metre-wide roadway at 7am (NZDT).

Pike River chief executive Peter Whittall noted this drilling was an “excellent job” to have hit the roadway, but the first gas samples only confirmed a lethal atmosphere.

“As we expected, the air that came out of the hole was extremely high in carbon monoxide, very high in methane and fairly low in oxygen,” he said during this morning’s media conference.

While some footage was taken from a camera placed down the hole, Whittall did not bring it to the conference as it was “pretty much black”

He also provided some insight into the possible cause of the gas explosion which rocked the colliery.

“There was a major event, a major hazard occurred at the time, no one would have known anything about the environment underground, you could only assume it was extremely hazardous and everything we have done since that has confirmed it,” he said in response to a question at the conference.

New South Wales southwest district secretary of the Construction Forestry Mining and Energy Union Graham White recently revealed some of the industry chatter to ILN.

He heard that the main ventilation fan had lost power and when it restarted the explosion happened.

What remains unclear is the sophistication of the gas monitoring underground before the explosion at the small Pike River mine, which only began hydro-mining less than two months ago.

Drilling of another borehole to gain additional gas information at the mine is underway.

Robots in the main access tunnel

The first army land-mine disposal robot short-circuited yesterday about 550m into the mine as it could not handle the wet conditions.

This robot was restarted overnight and was about 1000m in before its battery ran out.

The second land-mine disposal robot was flown in yesterday and is about 800m down the tunnel, Whittall said at the media conference this morning.

The only noteworthy footage so far was the discovery of electrician Russell Smith’s cap lamp, which was still on, with Whittall noting the manufacturer would be happy with this result.

Smith was one of the two miners who walked out of the mine after the explosion on Friday afternoon, and he was in a far better section underground than the 29 miners who remain missing.

But a tunnel inspection vehicle from the Water Corporation in Western Australia has arrived and is expected to have more success than the other robots.

The remote-operated, skid-steered vehicle has eight cameras, a gas detector and a microphone, and can handle getting wet.

The machine is designed to travel up to 4 kilometres down a tunnel, but its size might prove to be a problem.

Whittall is unsure whether it can get past the load haul dump some 1400m into the mine.

Other Pike River survivor Daniel Rockhouse was thrown off the LHD by the force of the underground explosion and it is believed to be in the middle of the roadway.

There is still a risk of a secondary explosion taking place.

The idea of sending in a robot has received scientific criticism on the basis the machines are not flame-proof or intrinsically safe.