HIBBING — Authorities say speed apparently contributed to last week’s crash in Hibbing of a tanker truck carrying 40,000 pounds of an explosive material.

The 62-year-old driver from the small Minnesota town of Virginia was trying to turn off a highway into the entrance of Hibbing Taconite when the tanker truck rolled Aug. 16.

Authorities say none of the ammonium nitrate spilled from the tanker. The chemical is used in the blasting process at the site.

The driver suffered minor injuries. A portion of Highway 5 near the plant entrance was closed for several hours.

The St. Louis County sheriff’s office says the Minnesota State Patrol inspected the vehicle and found no violations.

The sheriff’s office says the case has been referred to the St. Louis County Attorney’s office in Hibbing for appropriate charges.