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Asset Retirement Obligation (Details) (USD $)	3 Months Ended		6 Months Ended
Asset Retirement Obligation (Details) (USD $)	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Asset Retirement Obligation [Abstract]
Asset retirement obligation at beginning of period	$ 4,878,100	$ 4,511,600	$ 4,836,500	$ 4,444,900
Liabilities settled	(800)		(20,800)
Accretion expense	61,600	66,600	123,200	133,300
Asset retirement obligation at end of period	$ 4,938,900	$ 4,578,200	$ 4,938,900	$ 4,578,200

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

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