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SHAREHOLDERS' EQUITY (Details) |  |  |  |  | 12 Months Ended
--- | --- | --- | --- | --- | ---
Oct. 01, 2015 USD ($) shares | Aug. 17, 2015 $ / shares | Jun. 18, 2015 $ / shares | Jan. 24, 2012 USD ($) | Dec. 31, 2015 CAD / shares shares | Dec. 31, 2015 USD ($) $ / shares shares | Dec. 31, 2014 USD ($) $ / shares shares | Dec. 31, 2013 USD ($) $ / shares shares
Exchangeable shares converted into common stock | shares |  |  |  |  |  | 4,300,000 | 3,700,000 |
Exchangeable, shares outstanding | shares |  |  |  |  | 24,213,000 | 24,213,000 | 28,521,000 |
Common stock issued | shares |  |  |  |  | 274,421,000 | 274,421,000 | 271,579,000 |
Shares of common stock issued upon exercise of stock options | shares |  |  |  |  |  | 272,000 | 1,499,000 | 48,000
Weighted average exercise price of stock options (in dollars per share) | $ / shares |  |  |  |  |  | $ 1.29 | $ 1.29 | $ 1.97
Exercise of stock options | $ |  |  |  |  |  |  | $ 1,932,000 | $ 95,000
Proceed from exercised stock options | $ |  |  |  |  |  |  | 2,292,000 | 171,000
Shares issued for settlement of accounts payable | $ |  |  |  |  |  | $ 443,000 | 1,004,000 |
Annual return of capital declared (in dollars per share) | $ / shares |  |  | $ 0.01 |  |  |  |  |
First semi-annual return of capital payable (in dollars per share) | $ / shares |  | $ 0.005 |  |  |  |  |  |
Return of capital distribution (note 10) | $ |  |  |  |  |  | $ 1,503,000 |  |
Number of shares remaining under agreement | shares |  |  |  |  |  | 319,640 |  |
Share repurchase program | $ |  |  |  |  |  | $ 1,769,000 |  |
Period of time over which common stock can be repurchased | 12 months |  |  |  |  |  |  |
Share repurchase program (in shares) | shares |  |  |  |  |  | 1,896,442 |  |
Agreement to Terminate TNR Gold Corp Back In Right |  |  |  |  |  |  |  |
Shares issued to TNR Gold Corp's to terminate back-in-right | $ |  |  |  |  |  |  | 1,352,000 |
Exploration costs | $ |  |  |  |  |  | $ (8,798,000) | (11,332,000) | $ (24,829,000)
Maximum |  |  |  |  |  |  |  |
Share repurchase program | $ | $ 15,000,000 |  |  |  |  |  |  |
Share repurchase program (in shares) | shares | 15,000,000 |  |  |  |  |  |  |
TNR |  |  |  |  |  |  |  |
Agreement to Terminate TNR Gold Corp Back In Right |  |  |  |  |  |  |  |
Shares issued to terminate TNR Gold Corp's back-in right (in shares) | shares |  |  |  |  |  | 850,000 |  |
Net smelter return (as a percent) |  |  |  |  |  | 0.40% |  |
Exploration costs | $ |  |  |  |  |  |  | $ (1,400,000) |
Minera Andes |  |  |  |  |  |  |  |
Shares of common stock issued upon exercise of stock options | shares |  |  |  |  |  | 198,000 |  |
Weighted average exercise price of stock options (in dollars per share) | CAD / shares |  |  |  |  | CAD 1.96 |  |  |
Proceed from exercised stock options | $ |  |  |  | $ 0.4 |  |  |  |
Proceeds from issuance of new shares, net of expenses | $ |  |  |  |  |  | $ 400,000 |  |
Common Stock |  |  |  |  |  |  |  |
Shares of common stock issued upon exercise of stock options | shares |  |  |  |  |  |  | 1,499,000 | 48,000
Exercise of stock options | $ |  |  |  |  |  |  | $ 1,932,000 | $ 95,000
Shares issued for settlement of accounts payable (in shares) | shares |  |  |  |  |  | 430,000 | 394,000 |
Share repurchase program | $ |  |  |  |  |  | $ 1,769,000 |  |
Share repurchase program (in shares) | shares |  |  |  |  |  | 1,896,000 |  |
Shares of common stock issued as payment for mining concessions in Mexico | shares |  |  |  |  |  |  |  | 41,000
Agreement to Terminate TNR Gold Corp Back In Right |  |  |  |  |  |  |  |
Shares issued to terminate TNR Gold Corp's back-in right (in shares) | shares |  |  |  |  |  |  | 850,000 |
Shares issued to TNR Gold Corp's to terminate back-in-right | $ |  |  |  |  |  |  | $ 1,352,000 |

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