Note 12. Fair Value Measurement (Tables)

6 Months Ended

Jun. 30, 2011

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Table Text Block]

Description	Balance at  June 30, 2011		Balance at December 31,2010		Input Hierarchy Level
Assets:
Cash and cash equivalents:
Money market funds and other bank deposits	$	377,436	$	283,606	Level 1
Available for sale securities:
Equity securities – mining industry		4,161		2,668	Level 1
Trade accounts receivable:
Receivables from provisional concentrate sales		43,430		36,295	Level 2
Restricted cash balances:
Certificates of deposit and other bank deposits		926		10,314	Level 1
Total assets	$	425,953	$	322,883
Liabilities:
Derivative contracts:
Base metal forward contracts	$	11,597	$	20,794	Level 2