It's been 3 months and still no answers about Muskrat Falls formworks collapse

An official with Nalcor Energy says a clean-up is underway at the site of a serious industrial accident at the Muskrat Falls construction project, and the area has been deemed safe for the resumption of construction activities.

"Astaldi (has) started work to safely and carefully remove the material from the draft tube that was associated with this incident," Nalcor spokesperson Karen O'Neill wrote Friday in an email to CBC News.

But there's still no definitive answers as to why a specialized wooden formwork collapsed on May 29, spilling some 500 cubic metres of wet concrete and rattling workers on the massive and controversial project.

That's the equivalent of about 17 concrete basements for an average sized home.

"The investigation is very comprehensive and is looking at many factors," O'Neill explained.

"The investigation into the root cause is still ongoing and therefore a full analysis has not yet been completed."

Astaldi Canada, a division of the Italian firm, has the construction contract for the powerhouse and intakes for the Lower Churchill Project at Muskrat Falls in central Labrador.

No serious injuries in incident

The project had been dogged by controversy, most notably cost and schedule overruns, and a dispute between Astaldi and Nalcor over construction costs.

In June, Nalcor's new chief executive officer, Stan Marshall, agreed it was appropriate to describe the project as a boondoggle.

But new worries arose in late May during construction of draft tube No. 2, one of four large concrete pipes that will return water to the Churchill River after it runs through the power turbines.

Wooden formwork designed and built by a Kansas company, called Contractor's Engineer Inc., collapsed as concrete was being poured.

There were no serious injuries, but work on that section of the project was suspended.

Nalcor did not say how long the clean-up will take, how the concrete will be removed, or what affect the collapse will have on the project.

It's also unclear how much the collapse will cost, and who is picking up the tab.