BILLINGS, Mont. (AP) — The Northern Cheyenne tribe plans additional investigations of cultural sites along the path of a proposed railroad that would open new areas of southeastern Montana to large-scale coal mining.

Tribal council member Conrad Fisher said elders will revisit areas previously surveyed for the Surface Transportation Board.

Fisher says the tribe wants to ensure sacred and important sites are protected as the agency considers the Tongue River Railroad.

Landowners and members of other tribes with ties to the area say Surface Transportation Board contractors misinterpreted the significance of some cultural sites and overlooked others.

The $403 million rail line from Colstrip to the town of Ashland north of the Wyoming border is proposed by BNSF Railway, Arch Coal and candy industry billionaire Forrest Mars Jr.

BNSF spokesman Matt Jones said the railroad had confidence in previous cultural survey work done by government contractors.