A ventilation control device has been installed in the Pike River mine which means fresh air can circulate more than 2000m up the drift.
A post on social media by the Pike River Recovery Agency said the device, VCD2, was installed on Tuesday.
It is sitting about 2224m up the drift and acts as a wall with an airlock.
Now that it is in place, fresh air will be able to be circulated right up to that point in the drift.