Note 12. Fair Value Measurement

6 Months Ended

Jun. 30, 2011

Fair Value Disclosures [Text Block]

Note 12. Fair Value Measurement

The table below sets forth our assets and liabilities that were accounted for at fair value on a recurring basis and the fair value calculation input hierarchy level that we have determined applies to each asset and liability category (in thousands).  

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

Cash and cash equivalents consist primarily of money market funds and are valued at cost, which approximates fair value.

Current and non-current restricted cash balances consist primarily of certificates of deposit and U.S. Treasury securities and are valued at cost, which approximates fair value.

Our current and non-current investments consist of marketable equity securities which are valued using quoted market prices for each security.

Trade accounts receivable include amounts due to us for shipments of concentrates and doré sold to smelters and refiners.  Revenues and the corresponding accounts receivable for sales of metals products are recorded when title and risk of loss transfer to the customer (generally at the time of shipment).  Sales of concentrates are recorded using estimated forward prices for the anticipated month of settlement applied to our estimate of payable metal quantities contained in each shipment.  Sales are recorded net of estimated treatment and refining charges, which are also impacted by changes in metals prices and quantities of contained metals.  We estimate the prices at which sales of our concentrates will be settled due to the time elapsed between shipment and final settlement with the smelter.  Receivables for previously recorded concentrate sales are adjusted to reflect estimated settlement metals prices at the end of each period until final settlement by the smelter.  We obtain the forward metals prices used each period from a pricing service.  Changes in metal prices between shipment and final settlement result in changes to revenues previously recorded upon shipment.  The embedded derivative contained in our concentrate sales is adjusted to fair market value through earnings each period prior to final settlement.

During the second quarter of 2010, we began utilizing financially-settled forward contracts to manage the exposure of changes in prices of zinc and lead contained in our concentrate shipments that have not reached final settlement.  We also began utilizing financially-settled forward contracts in the second quarter of 2010 to manage the exposure of changes in prices of zinc and lead contained in our forecasted future concentrate shipments (see Note 11 for more information).  These contracts do not qualify for hedge accounting, and are marked-to-market through earnings each period.  The fair value of each contract represents the present value of the difference between the forward metal price for the contract settlement period as of the measurement date and the contract settlement metal price.