Solid Energy is "disappointed" that Allied Concrete has decided not to supply the company to help seal the Pike River mine.
But the company says it is continuing with the sealing process which has been underway for nearly two years.
In a statement, Solid Energy says their focus is "the construction of a thicker stronger seal that provides a more robust barrier against any pressure surge in the mine."
The seal is scheduled to be completed early next year.
Earlier today Allied Concrete, the company that was contracted to supply concrete to permanently plug the mine, announced they had pulled out of the job.
The decision came after two women, who had lost men in the horrific 2010 tragedy, made a desperate plea to contractors working on the seal to stop.
The concrete seal would draw an end to six years of fighting by the families of the 29 men killed in the disaster, to re-enter the mine to retrieve evidence, and hopefully bodies.
Allied Concrete is owned by HWR, and chief executive Brent Esler said today they had been asked to quote for the supply of concrete by a contractor engaged by Solid Energy.
HWR had "the deepest sympathy for the families of the 29 miners whose lives were lost in the disaster in 2010".
"We are respectful of their feelings around the sealing of the mine. We also understand the situation faced by Solid Energy who are now trying to prevent further risk of injury or fatalities."
The company was mindful that Solid Energy was not the mine operator at the time of the 2010 disaster but took over in 2012.
"At this time Allied Concrete have not committed to supply concrete material for the final stages of the project," Allied said. "We will assess any decision to supply product as it arises."
The company said it hoped an understanding could be reached between the parties and that some finality was achieved for everyone, "after this tragic event".
Pike River families are welcoming the company's decision not to supply the concrete required to seal the mine.
Allied has contacted Sonya Rockhouse, whose son Ben was killed in the mine, to assure her they will halt supply until the dispute over re-entering the mine is resolved.
"We are incredibly relieved by this decision," Rockhouse said.
"Allied has shown real moral strength in stopping this work and is a great example of a good family business.
"We understand this means the sealing of the mine cannot go ahead, and we're grateful to Allied and to all of the Kiwis who have supported us to stop the mine being sealed.
"We have never lost faith in New Zealanders' belief in doing the right thing, and we're hoping that this sends a message to the Government to follow suit and to honour John Key's promise to get our boys out.
"We have international and local experts who say the drift is safe to enter. There may be the bodies of our boys in there as well as evidence that shines a light on what happened that terrible day.
"All we want is the chance to go in and check before our boys and any evidence is sealed away forever."
On-site at Atarau, Karl Barkley remained the sole protester on the mine access road this morning. Police reported no issues.
Online, the campaign to stop the sealing continued, and some family members said people should tell Prime Minister John Key and Solid Energy and its directors, how they felt about it: "Is this seriously the cowardly legacy they want to be remembered for?"
Contractors were again asked to "do the right thing and walk away today" from helping with the permanent seal.
"The families will help carry your gear back up to get on with work again once the drift has been searched."
- Additional reporting: Greymouth Star