True Cost of Coal Act of 2012 - Amends the Internal Revenue Code to: (1) impose a $10 per ton excise tax on the extraction of coal; (2) establish in the Treasury the Coal Mitigation Trust Fund to hold revenues from such tax; and (3) extend to 50 years the recovery period, for depreciation purposes, for specified coal port property used for the export of coal.
Allows expenditures from the Coal Mitigation Trust Fund to assist states in mitigating noise, vibration, traffic delays, pollution and other threats to public health, and emergencies in connection with the transportation of coal by rail, and to provide worker adjustment assistance.
Directs the Secretary of Transportation (DOT) to issue regulations to require all rail cars transporting coal to be covered or to incorporate a suitable alternative technology to ensure that coal and coal dust do not escape during transportation.