MINNEAPOLIS — Lawyers for the Mesabi Nugget iron processing plant near Hoyt Lakes have moved to protect the company's variance from Minnesota's water quality standards.

The company filed a motion in federal court Thursday asking for a 30-day delay of any decision on whether to let the Environmental Protection Agency rescind its approval for the variance.

Mesabi Nugget says it had no advance warning of the EPA's decision and wants time to meet with agency officials to find out why they're reversing course. The company says it faces immediate and substantial harm if it loses its variance.

Environmental groups and Chippewa bands sued the EPA last year to block the variance, saying it improperly allows plant to exceed state standards for pollutant discharges.

A hearing is set for April 24 in Duluth.