Police today said the nitrogen generator (Floxal) had been operating all night at Pike River coal mine.
Overnight the Floxal has been working in tandem with the GAG to neutralise and cool the environment within the mine.
Planning is under way today to turn off the GAG at some stage to measure the effect the Floxal is having on the environment.
The situation is being monitored with real-time gas testing and overnight those readings were described as "positive".