Work Safe New Zealand has agreed to extend the Pike River Mine sealing deadline to June.
The daily picket by mine families and supporters, which started just before the November 19 anniversary of the disaster, has resulted in West Coast contractors refusing to do the sealing work.
Read more: Emotional silent protest at Pike River Mine entrance
Solid Energy requested an extension.
Documents released under the Official Information Act by Work Safe NZ late last year show the mine already has a 1m-thick seal inside the drift, which is the stone drive entrance to the mine proper.