Four weeks after a tug ran aground and sank near Bella Bella, the salvage operation continues on the North Coast of B.C.

The salvage company is trying to drag the tug over to a larger barge, but weather and tides continue to hamper the operation, according to Heiltsuk Chief Councillor Marilyn Slett.

Efforts are underway to drag the tug over to and then onto a barge anchored nearby. (Kyle Artelle/Heiltsuk Nation)

The tug has to be dragged about 300 metres across the sea floor to the barge before it can be hoisted out of the water, she said.

"They started yesterday afternoon and didn't get very far but they worked throughout the night and were about 25 per cent complete," said Slett on Thursday morning.

Heiltsuk first responders Collin Reid and Jeff Brown have been monitoring the recovery efforts and the spread of the leaking fuel. (Kyle Artelle/Heiltsuk Nation)

Because the tug was stuck in an underwater trough, the salvage crew decided to try to increase its buoyancy by strapping on lift bags and pumping its empty tanks full of air on Thursday morning,

It remains unclear how much longer the operation might take, said Matt Lewis, the incident commander for Kirby Offshore Marine, which owns the sunken tug.

Crews have also been assessing the sea floor in order to minimize damage. Nevertheless, concerns remain about damage the dragging operation might do, said Slett.

There are concerns that dragging the tug to the barge will cause more damage to the marine environment. (April Bencze/Heiltsuk Nation)

The stormy fall weather and strong tides have limited the windows in which the crews are able to work.

"Its been a long process. We want to see this done right and safely and without further damage," Slett said.

Stormy weather and tides have limited the time the crew has to work on the recovery operation. (Kyle Artelle/Heiltsuk Nation)

Even though the fuel tanks on the vessel were emptied two weeks ago, she said there was a new slick of heavy residual oil spotted a few days ago.

Lewis said the amount of fuel in the most recent spill was quite small.

Despite efforts to pump out all fuel and oil from the tug, there was a small slick at the site recently. (Kyle Artelle/Heiltsuk Nation)

The tug ran aground in the early morning hours of Oct 13. At the time, it was pushing an empty fuel barge.

While the barge was safely towed away, some diesel fuel from the tug did spill into the water, potentially endangering local wildlife.

Floating booms are being used to try to protect the shoreline from spilled fuel and oil. (Tavish Campbell/Heiltsuk Nation)

Testing is underway, and officials with Health Canada have yet to determine the extent to which the spilled fuel has affected local food sources for the band, including nearby clam beds.

"We've been doing the assessments since the beginning. Things are still looking uncertain for us," Slett said.

Crews are monitoring the impact of the spilled fuel on local wildlife and clam beds. (Kyle Artelle/Heiltsuk Nation)

The salvage operation was originally scheduled to begin shortly after the fuel removal from the tug finished on Oct. 27.

"We know this is far from the end, but after 28 long days the Heiltsuk are relieved to see movement of the sunken tug," she said.