Enbridge (TSX:ENB) said it anticipates as many as 75 workers would be on site Tuesday and the number will vary in the coming days.
"The site is very wet due to heavy rains and surface water is running down the slope to a small creek that discharges into an unnamed lake," company spokesman Todd Nogier said.
"Containment booms and absorbent mats (and) vacuum trucks will, or are, being used to remove any remaining products from the water bodies," Nogier said in an email. "The oil is contained."
Enbridge said it wants to clean up the site, about 70 kilometres southeast of Fort McMurray, as quickly as possible and ensure the safety of residents, wildlife and employees.
The weekend spill from Line 37 caused Enbridge to shut down its Athabasca and Waupisoo pipelines — a major part of the network that serves Alberta's oilsands.
The Calgary company also said service has returned to the Athabasca Line (Line 19) between Cheecham and Hardisty, Alta.
The Waupisoo Line (Line 18) is being assessed and may be cleared for restart later Tuesday, Enbridge said.
The 540-kilometre Athabasca line can carry up to 570,000 barrels per day of crude from the Athabasca and Cold Lake regions to Hardisty, Alta., a major pipeline hub in eastern Alberta, about 200 kilometres southeast of Edmonton.
The Waupisoo line can carry up to 600,000 barrels per day to Edmonton from Cheecham Terminal, near the site of the spill.
The company detected the Line 37 spill early Saturday and initially estimated that between 500 and 750 barrels of oil had spilled.
Enbridge said unusually heavy rains may have resulted in a ground movement that affected Line 37, a 17-kilometre-long, 12-inch diameter pipe linking the Long Lake oilsands upgrader with the Athabasca system.