A number of robots have been sent into Pike River Mine since the explosions that killed 29 men in 2010, but the results of their efforts are mixed.
Newly-released footage showing two men and a robot apparently inside the drift of the mine, three months after the final explosion, has led to calls for all such information to be released.
2010
- 19 November - About 3.45pm the first methane gas explosion hits, leaving 29 men trapped.
- 23 November - Relatives of the miners are told the Defence Force robot sent into the mine has broken down just 550m in, after reaching water.
- 24 November - A second robot enters the tunnel, and a third, more sophisticated robot, is also being readied. A fourth robot is en route from the US, due to arrive on Thursday morning.
- Photographs from the first Defence Force robot sent down the mine show the discarded cap lamp from one of the miners who escaped, Russell Smith.
- At 2.37pm the second explosion rocks the mine. Police move from rescue to recovery operations.
- 25 November - New video footage from 1600m into the mine reveals the extensive damage from the second blast, which extinguished hope for recovering the 29 trapped miners.
- 29 November - Cabinet agrees to establish a Royal Commission of Inquiry.
2011
- 10 March - Police say a fifth robot, equipped with a camera, should enter the mine in a week's time.
- 29 March - A spokesperson for Pike River Mine says the robot failed inside the mine.
- April - The Royal Commission's hearings into the disaster begin.
2012
- 5 November - The Royal Commission makes its report and recommendations public, focusing on changes to health and safety regulations.
2017
- 30 April - Police say they are considering a request to release all the video footage they have, including video taken by a robot used in the recovery efforts at the mine.
- Video footage emerges of two men and a robot apparently inside the drift of the mine, prompting questions as to whether it is actually too unsafe to enter it.
- 1 May - The government faces growing calls to release all the information it has on Pike River Mine.
- Hundreds of gigabytes of information about the disaster are yet to be released, the mother of one of the miners said, based on an Official Information Act response.
See also RNZ's timeline of the events of the 2010 disaster.