Australian mining firm Anglo American Plc has resumed operations in its Drayton coal mines after an accident this morning that affected five workers, hospitalizing four.

Of the four treated at hospital, one has been discharged and the fifth employee has returned to work, Anglo American said. The company is treating the incident "very seriously" and cooperating with all relevant authorities.

Aldo Pennini said in an emailed response: "Mining was stopped in order to brief employees on the incident," which occurred at 8:15 a.m. local time, in an e-mailed reply to Bloomberg. Operations have since resumed, he said.

Drayton, which is located 63 miles from Newport, produces about 5.5 million metric tons of power- station grade coal a year and employs about 300 workers, according to Anglo American's website.