Mines Rescue entering the Pike River Mine for the first time after the explosions at Pike River Mine.
2004
March: Approval given for Pike River Coal to open an underground mine within Paparoa National Park, near Greymouth on the West Coast.
2008
October: Pike River Coal formally opens the mine for production, with an expected output of one million tonnes of hard coking coal a year for 20 years, employing 150 staff.
2010
February: After a number of delays due to technical problems, the first shipment of coal (60,000 tonnes) from Pike River is exported.
November 19: A methane gas explosion occurs 2km inside the mine. Two workers walk out but 29 others are trapped in the tunnel, 150 metres below the surface. Specialist equipment is flown in to help rescue the miners, but they cannot be reached for days because of high gas levels.
November 24: A second explosion rocks the mine, and Pike River chief executive Peter Whittall tells families of the 29 miners that there is no chance the workers are still alive.
November 28: Prime Minister John Key announces Royal Commission inquiry into the mine tragedy, to be chaired by High Court judge Graham Panckhurst. The gases inside the mine remain volatile, preventing recovery of the bodies.
December 13: Pike River Coal placed in receivership.
December 15: Receivers announce 114 of 157 staff will be made redundant immediately, with compensation. Other staff and contractors receive no payout.
2011
January 14: Police abandon attempts to recover the 29 bodies.
July: Royal Commission hearings into the disaster begin, with 57 witnesses appearing and 200 written submissions received. A number of safety failings at Pike River are highlighted by witnesses. The Government is also criticised for watering down regulations and the mining inspectorate.
September 29: Peter Whittall sacked as chief of Pike River Coal.
November 11: Department of Labour lays charges in the Greymouth District Court for health and safety failings against Mr Whittall, Pike River subcontractor VLI Drilling and Pike River Coal.
2012
May 31: Families told by mining experts that bodies will probably never be recovered.
July 31: VLI Drilling pleads guilty to three health and safety-related charges, and is later fined $46,800. Families of the victims respond furiously to the penalty. Pike River Coal says it will not fight the 10 charges it faces.
October 25: Former CEO Peter Whittall pleads not guilty to 12 health and safety-related charges, and a trial date is set for March 2013.
November 5: Royal Commission's findings on Pike River tragedy released.
Polkinghorne was sentenced to 150 hours of community work for drug possession.