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FAIR VALUE ACCOUNTING (Details) (USD $) In Thousands, except Share data, unless otherwise specified |  |  |  | 1 Months Ended | 12 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010 | Nov. 30, 2012 Litigation settlement agreement with respect to the Los Azules Copper Project TNR | Dec. 31, 2012 Litigation settlement agreement with respect to the Los Azules Copper Project TNR | Dec. 31, 2012 Recurring Total | Dec. 31, 2011 Recurring Total | Dec. 31, 2012 Recurring Level 1 | Dec. 31, 2011 Recurring Level 1 | Dec. 31, 2012 Recurring Level 2 | Dec. 31, 2011 Recurring Level 2
Assets: |  |  |  |  |  |  |  |  |  |  |
Cash and cash equivalents |  |  |  |  |  | $ 70,921 | $ 13,416 | $ 70,921 | $ 13,416 |  |
Short-term investments |  | 3,933 |  |  |  |  | 3,933 |  | 3,933 |  |
Marketable equity securities | 3 | 1,480 | 4,576 |  |  | 3 | 1,480 | 3 | 897 |  | 583
Assets |  |  |  |  |  | 70,924 | 18,829 | 70,924 | 18,246 |  | 583
Liabilities: |  |  |  |  |  |  |  |  |  |  |
Accounts payable and accrued liabilities |  |  |  |  |  | 21,235 | 5,612 |  |  | 21,235 | 5,612
Litigation settlement liability | 3,830 |  |  |  | 3,800 | 3,830 |  | 3,830 |  |  |
Liabilities |  |  |  |  |  | $ 25,065 |  | $ 3,830 |  | $ 21,235 |
Shares of common stock required to be issued as part of settlement |  |  |  | 1,000,000 | 1,000,000 |  |  |  |  |  |

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