XML 64 R27.htm IDEA: XBRL DOCUMENT
v2.4.0.6

MINERAL PROPERTY INTERESTS AND ASSET RETIREMENT OBLIGATIONS (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2012
MINERAL PROPERTY INTERESTS AND ASSET RETIREMENT OBLIGATIONS |
Summary of mineral property interests |
The following table summarizes all of the Company’s mineral property interests in Nevada, Argentina and Mexico (in thousands):
Name of Property/Complex |  | State/Province |  | Country |  | Carrying Value |
Tonkin Complex |  | Nevada |  | United States |  | $ | 52,204 |
Gold Bar Complex |  | Nevada |  | United States |  | $ | 77,012 |
Limo Complex |  | Nevada |  | United States |  | $ | 50,098 |
Battle Mountain Complex |  | Nevada |  | United States |  | $ | 31,106 |
Other United States Properties |  | Nevada |  | United States |  | $ | 19,107 |
Los Azules Copper Project |  | San Juan |  | Argentina |  | $ | 431,190 |
Other Argentina Exploration Properties |  | San Juan |  | Argentina |  | $ | 7,819 |
Cerro Negro Region |  | Santa Cruz |  | Argentina |  | $ | 80,889 |
Other Argentina Exploration Properties |  | Santa Cruz |  | Argentina |  | $ | 19,194 |
Other Argentina Exploration Properties |  | Catamarca |  | Argentina |  | $ | 2,362 |
Other Argentina Exploration Properties |  | Chubut |  | Argentina |  | $ | 248 |
El Gallo Complex |  | Sinaloa |  | Mexico |  | $ | 9,469 |
Other Mexico Exploration Properties |  | Sinaloa |  | Mexico |  | $ | 4,580 |
Total |  |  |  |  |  | $ | 785,278 |
Schedule of changes in asset retirement obligations |
Changes in the Company’s asset retirement obligations for the nine months ended September 30, 2012 and year ended December 31, 2011 are as follows (in thousands):
|  | Nine Months Ended |  | Year Ended |
|  | September 30, |  | December 31, |
|  | 2012 |  | 2011 |
Asset retirement obligation liability- opening balance |  | $ | 6,253 |  | $ | 6,153 |
Settlements |  | (24 | ) | (82 | )
Accretion of liability |  | 342 |  | 524 |
Adjustment reflecting updated estimates |  | (79 | ) | (342 | )
Asset retirement obligation liability - ending balance |  | $ | 6,492 |  | $ | 6,253 |

X
- Details
Name: | mux_MineralPropertyInterestsAndAssetRetirementObligationsDisclosureAbstact
Namespace Prefix: | mux_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of mineral properties held by the entity. + References No definition available. + Details
Name: | mux_ScheduleOfMineralPropertiesTableTextBlock
Namespace Prefix: | mux_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13201-110859 + Details
Name: | us-gaap_ScheduleOfChangeInAssetRetirementObligationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration