The railroad north of Cloquet has reopened to train traffic as crews continue to clean up a 40-car train derailment that dumped more than 4,000 tons of coal along the track and onto the frozen St. Louis River Saturday.

The tracks reopened to traffic at about midnight Sunday and crews will spend the next week or two scrapping the derailed cars and moving the spilled coal out by rail, BNSF Railways spokesperson Amy McBeth said Monday.

No injuries were reported, but several derailed cars had landed on the frozen river and along its banks.

The exact amount of coal that spilled is unknown.

Makayla Telfer, a spokesperson for the Fond du Lac Reservation, citing BNSF’s field survey measurements, said 4,320 tons of spilled coal was a “conservative estimate.” However, the Cloquet Area Fire District wrote on Facebook that approximately 5,130 tons of coal spilled in the derailment. McBeth would not confirm either of those numbers Monday night.

McBeth said of the 121 loaded coal cars and three locomotives, 40 coal cars derailed at about 11:30 a.m. Saturday several miles north of Cloquet and along the St. Louis River.

Since the derailment happened within Fond du Lac, reservation agencies have the lead jurisdiction, Telfer said.

The cleanup process will be led by BNSF, however.

“The entire plan and process is under development by BNSF staff and contractors. The plans will be reviewed and approved by FDL Environmental staff for approval,” Telfer said.

Minnesota Pollution Control Agency spokesperson Lucie Amundsen said the agency was not working on the scene because it happened on Fond du Lac land, but said the MPCA was available to help if the band requests it.

Speaking broadly about the impact of coal spilled on land, ice and water, Amundsen said that if coal is cleaned up immediately, its impact on the environment will be minimal.

“A spill on land, cleaned up right away, generally has no impact,” Amundsen said.

As for a spill on ice or in water, “coal is generally not water soluble,” Amundsen said. “There are different types of coal, depending on the type, you could see some low amounts of sulfur, but if a spill is cleaned up right away, there is generally not an impact.”

The coal was heading to Minnesota Power’s Boswell Energy Center, the company’s only operating coal-fired power plant, but the derailment did not cause any disruption to service at the plant, Minnesota Power spokesperson Amy Rutledge said. The shipment originated from the Powder River Basin in Wyoming, Rutledge said.

The NTSB can choose which incidents to investigate, and is not currently investigating Saturday’s derailment, McBeth said.