A handful of Attawapiskat band members blocked the key supply line to the Victor diamond mine on-and-off for nearly three weeks.
The company received a court injunction to break up the blockade, which ended peacfully on Friday night.
But company spokesperson Tom Ormsby said the lost transit time will be difficult to make up.
"We believe ... we've passed the point of being able to get everything in," Ormsby said.
"So at this point, we're hoping that the teams will continue to move efficiently, and we're also keeping our fingers crossed that we'll see some extended cold periods in the weather ... to maintain the integrity of the road, to give us as long as possible."
Ormsby said it's too early to put a number on how much the lost productivity cost De Beers and noted civil lawsuits to recover lost revenue are still a possibility.
He added the company will continue in open talks with the community.
Provincial police said a handful of protesters left the road on Friday night without incident.
A court injunction was issued earlier this month, ordering that the road be re-opened to traffic, but protestors remained. Police said they were waiting on specific instructions from the court on exactly how to proceed with ending the blockade peacefully. In the end, police said no intervention was required to remove the road block.
Moving forward, officers will stay on site and monitor the situation to ensure supplies are transported to and from the mine safely.
Ormsby said the blockade by Attawapiskat band members cost the company 16 of 20 days of ice road use since the temporary road was opened for the season.
The mine employs about 500 people, including roughly 100 from the neighbouring Attawapiskat First Nation.