A look at work on the North Spur dam for Muskrat Falls

Nalcor announced this week budget costs at the Muskrat Falls hydroelectric project have gone over budget by another 10 per cent.

Part of those rising costs is the contract for work on the North Spur stabilization project, which was more expensive than originally expected.

• Muskrat Falls cost increase shows poor management from Nalcor, says Dwight Ball
• Muskrat Falls another 10% over budget, cost climbs to $7.65B

Earlier this week, Nalcor CEO Ed Martin announced costs had risen to $7.65 billion and first power was pushed back to 2018. When the project was initially announced in 2010, the cost was forecast to be $5-billion.

In 2012 that number was up to $6.2 billion, and in 2014 it jumped to $6.99 billion.

The North Spur is a jut of rock and deep soil in the Churchill River on the north side of Muskrat Falls.

The upstream side of the spur will take the full weight of the reservoir that will be created by the hydroelectric complex.

The work at the North Spur will focus on strengthening the already existing natural barrier, to ensure the sand and clay land around the Lower Churchill doesn't shift with the construction of the reservoir.

"We're just finishing off a cement bentonite cutoff wall, it's being constructed from river elevation. It extends down approximately 20 metres, 25 metres at different elevations," said Mark Turpin, area construction manager with Nalcor.

"It is currently just being finished off and that will create a barrier for water to pass underneath. We'll cut off the water flow of the river going underneath the spur. It goes down approximately as indicated 80 feet and it keys into an impervious clay layer."

Turpin said drainage systems are being put in place on the other side of the spur to take care of any water that does make its way through.

"What we're doing on the upstream side is we create a curtain to prevent water from going through the spur. On the downstream side, we've got drainage spurs going in to help take water out of the spur."

In addition to higher costs for work at the North Spur, over-budget costs for contracts to construct the north and south dams and issues with contractor performance and weather conditions also contributed to the overall cost climbing to $7.65 billion.