Pike River Coal has broken through the Hawera Fault, which was seen as a last major hurdle for tunnellers at its new mine on the West Coast.
Another 182m of tunnel still needs to be drilled to reach the Brunner coal seam where the company plans to extractat least 17.6 million tonnes over the next 18 years. The mine in the Paparoa Range inside a national park is extracting export premium hard coking coal.
Tunnelling slowed to 1m a day as miners worked through the fault.
"While it's possible more fractured rock could again be found in this area near the fault, the most difficult mining challenge is over and tunnel advance rates are expected to improve significantly," mines general manager Peter Whittall said.
Virtually no water and little gas was encountered, which was good news.
Tunnelling started almost two years ago and the coal should be reached around the end of August.
The mine is expected to produce 100,000 tonnes of saleable coal by the end of March next year, a further 100,000 tonnes to the end of June, and from then on, an average of about one million tonnes-a-year. A coal preparation plant is nearly complete and a train load-out facility is being built at Ikamatua, 54km north of Greymouth.
Pike River shares - among the best performers on the NZX this year - rose 6c on the news to close at $2.05.
