Question: Some large coal-burning power plants are located at the mouth of a mine and have been designed to burn coal specifically extracted from that mine. Others are at a distance from mines. Coal can reach them by rail from many different mines, and they are not as dependent on a particular type of coal as mine-mouth plants. Why do you expect that the owner of the mine-mouth plant is more likely to own its coal supplies than the owner of one located at a greater distance from mines?