Conrad Adams, 43, is assumed to be dead along with 29 other miners from the Pike River mine disaster in New Zealand.

According to the New Zealand Herald, Adams sent a “friend” the following text on October 6:

“Fan on stop 20 hours. Whole mine gassed out to f**k. Off to de-gas. Mining updip has its down sides ay?"

The newspaper also reported that another text sent on October 19 revealed the mine had gas issues in its development areas.

"Are you allowed to cut with a continuous miner updip in four cubic metres per sec from fan? Gassy area? Strong smell of hydrogen sulphide as well as from drillers stub," Adams reportedly wrote.

Hydrogen sulfide is a poisonous and flammable gas.

The anonymous friend reportedly claimed that the gas drainage pipes used were too narrow and “created back pressure”

The newspaper said the unknown source also believed that Pike valued “production over safety”.

Prior to the explosion, the Pike River mine conducted in-seam drilling for gas drainage purposes.

Footage outside the mine entrance during the first blast also revealed that ventilation had stopped for at least a “few minutes” beforehand, in the words of Pike chief executive Peter Whittall during a press conference while he showed the captured video.

But the clip was short with a lot of it showing the blast’s pressure wave exiting the mine, so it is not clear how long the ventilation system was down for.

If the main ventilation fan stops it can allow methane to dangerously accumulate.

In Australian underground coal mines an evacuation would be underway if a main fan stopped for more than 30 minutes.

But with long-established real-time gas monitoring systems in place, an evacuation would start in far less time as rising gas levels are detected.

What fixed, real-time gas monitoring was in place at the Pike River mine remains unclear, while New Zealand legislation lacks specific regulations on this technology.

There have been a total of five explosions at the mine so far, but the likelihood of smouldering material underground and high levels of methane could fuel more explosions.

The Pike mine was behind-budget before the explosion and cut its production forecast in October from 620,000 tonnes of saleable coking coal to 320,000-360,000t for this financial year.

Meanwhile, the mine is set to be inerted this week with the GAG unit supplied by Queensland Mines Rescue Services.