For the last year EarthFix has been looking at the issue of coal being exported through the Northwest.
There are five proposed coal export terminals under consideration in Washington and Oregon. They would be built to transfer coal off of trains from Wyoming and Montana mines and on to ships bound for Asia.
Some coal dust will escape along the journey from the mines to the terminals.
The Black Thunder mine located near Gillette, Wyoming is one of the largest open pit mines in the world.