Clean/dirty Coal

Content index:

Geologic formation of coal:


Leaf fossil from sediments associated with a coal seams in the Matanuska valley of Alaska, documenting the terrestrial environment the coal formed in here. The types of leaves also indicate something about the climate at the time.

Types of coal:

Soft brown coal, not deeply buried. Image source:

anthracite (dark and shiny) USGS image.

Relationship between types of coal and energy content. Note that the energy content x-axis decreases to the right. Diagram source:

Environmental concerns associated with coal as an energy source: the list is long.

Image source:


Mining techniques:

USGS image of strip mining in the Powder River Basin. Note the incredible thickness of the coal deposits. Image source:

Image of the mining of a coal seam in an underground coal mine. Source:

Reclaimed strip mine in the Matanuska valley of Alaska; from geology field trip in 2007.

How much is there? Coal reserves and resources:

Map of major coal bearing basins in the U.S.. Image from:

Clean coal - what are the possibilities?

Replacement of coal by natural gas in power plant electricity generation due to increase natural gas production by fracking operations and associated price drop.