4a. Economically Recoverable Coal
Before coala dark brown to black combustible rock of organic origin formed over millions of years by the partial decomposition of... Read More mining can begin, a team of drillers and geological engineers survey the coal field to see if mining would be profitable. The following criteria help determine whether or not a coal field is economically recoverable:
Cumulative coal bed thickness of 10 or more feet
No areas in the coal bed under 2.5 feet thick
On average, between 25 and 175 feet below the surface
Minimal amount of coal seams split by dirt deposits
