Supplemental Coal Data (unaudited)



	Millions of Tons
	For the Year Ended December 31,
	2014		2013		2012		2011		2010
Proved and probable reserves at beginning of period	3,032		4,229		4,314		4,229		4,350
Purchased reserves	—		1		—		6		4
Reserves sold in place	(233	)	(1,199	)	(155	)	—		(41	)
Production	(32	)	(55	)	(55	)	(62	)	(62	)
Revisions and other changes	471		56		125		141		(22	)
Consolidated proved and probable reserves at end of period*	3,238		3,032		4,229		4,314		4,229

Proportionate share of proved and probable reserves of unconsolidated equity affiliates (excluded from the table above)*	55		57		41		145		172

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* Proved and probable coal reserves are the equivalent of “demonstrated reserves” under the coal resource classification system of the U.S. Geological Survey. Generally, these reserves would be commercially mineable at year-end prices and cost levels, using current technology and mining practices.

CONSOL Energy's coal reserves are located in nearly every major coal-producing region in North America. At December 31, 2014, 319 million tons were assigned to mines either in production or temporarily idled. The proved and probable reserves at December 31, 2014 include 2,759 million tons of thermal coal reserves, of which approximately 5 percent has a sulfur content equivalent to less than 1.2 pounds sulfur dioxide per million British thermal unit (Btu), 17 percent has a sulfur content equivalent to between 1.2 and 2.5 pounds sulfur dioxide per million Btu and an additional 78 percent has a sulfur content equivalent to greater than 2.5 pounds sulfur dioxide per million Btu. The reserves also include 480 million tons of metallurgical coal in consolidated reserves, of which approximately 41 percent has a sulfur content equivalent to less than 1.2 pounds sulfur dioxide per million Btu and an additional 59 percent has a sulfur content equivalent to between 1.2 and 2.5 pounds sulfur dioxide per million Btu.

Our estimate of proven and probable coal reserves has been determined by CONSOL Energy’s geologists and mining engineers. CONSOL Energy geologists and mining engineers completed an extensive re-evaluation of the longwall mineable Pittsburgh and Illinois No. 5 seams during 2014. The re-evaluations included the use of mine specific assumptions and mine plans versus general mine recovery factors and general parameters. To date, approximately 50% of CONSOL Energy’s reserves have been re-evaluated using mine specific parameters as opposed to an assumed average mining recovery factor. The 2014 re-evaluations resulted in 407 million of the total 471 million additional tons of proven and probable reserves added as result of revisions and other changes in 2014. During 2014, Golder Associates (Golder) audited approximately 86% of the above revisions and other changes that occurred in 2014.