GILLETTE, Wyo. (AP) — A worker has died at one of the vast coal mines in northeast Wyoming.

Peabody Energy officials say the worker was a contractor who was processing scoria at the North Antelope Rochelle Mine in the Powder River Basin.

The Gillette News-Record reports emergency responders got a report just before 6 a.m. Wednesday that someone was caught in a hydraulic crusher at the surface mine.

Authorities and company officials didn't identify the worker. St. Louis-based Peabody says an investigation is under way.

Federal figures show six people have died at U.S. coal mines this year. Twenty died at U.S. coal mines last year, including two at coal mines in Wyoming.

North Antelope is the top-producing U.S. coal mine and produced 111 million tons of coal last year.