UNDERWOOD, N.D. (AP) - Contractors have been drilling along state Highway 200 near here, looking for signs of abandoned mines that could cause part of the highway to collapse.

Bill Dodd, an assistant director of the Public Service Commission's Abandoned Mine Lands Division, said the division finished an emergency project last week near Beulah and Hazen. The two sink holes measured 30 feet and 17 feet.

"We were especially worried, with pheasant hunting opening, that somebody might fall in," Dodd said.

The state gets involved when abandoned mines pose dangers to roads, housing developments or people involved in use of the land, Dodd said.

Although the state's most extensive and serious problems have been in the Beulah and Hazen areas, the division has been involved in reclamation in the Noonan and Columbus areas in recent years, Dodd said.

Division officials also plan more work near Sawyer and Velva to address sink holes and high walls. Other projects completed in the past in the Minot area have been at Garrison, Burlington and Parshall.

North Dakota's underground mines date existed before 1960. Strip mining became the preferred means of mining in later years, although there were no state or federal requirements for land reclamation until the 1970s.

A federal fee on coal production has funded abandoned mine reclamation for the past 26 years. North Dakota's abandoned mine division has repaired more than 100,000 linear feet of high wall and 1,800 underground acres in that time, officials said.

The state has spent about $30 million so far on abandoned mines and has estimated another $40 million in work remains.