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: http://gallery.usgs.gov/photos/09_10_2009_cg8Jam4YYt_09_10_2009_3

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: http://pubs.usgs.gov/circ/c1143/html/fig17.html


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

Image source: http://pubs.usgs.gov/circ/circ1202/major_findings.htm

 

Mining techniques:

USGS image of strip mining in the Powder River Basin. Note the incredible thickness of the coal deposits. Image source: http://energy.er.usgs.gov/coal_assessments/

Image of the mining of a coal seam in an underground coal mine. Source: http://pubs.usgs.gov/fs/fs004-02/fs004-02.html

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: http://energy.cr.usgs.gov/oilgas/cbmethane/pubs_data.html


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.