XML 37 R56.htm IDEA: XBRL DOCUMENT

Reclamation and Mine Closure (Details) (USD $)	3 Months Ended
Reclamation and Mine Closure (Details) (USD $)	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Asset retirement obligation
Asset retirement obligation - Beginning	$ 33,434,000	$ 32,714,000
Accretion	743,000	724,000
Addition and changes in estimates	0	0
Settlements	(2,000)	(4,000)
Asset retirement obligation - March 31	34,175,000	33,434,000
Reclamation and Mine Closure (Textual) [Abstract]
Accrued reclamation liabilities	$ 800,000		$ 900,000

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.

+ References+ Details

- 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.

+ References+ Details