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ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS ENVIRONMENTAL AND MINE CLOSURE OBLIGATIONS (Tables) | 12 Months Ended
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Dec. 31, 2016
Environmental Remediation Obligations [Abstract] |
Schedule of Environmental Loss Contingencies and Asset Retirement Obligations [Table Text Block] | The following is a summary of the obligations as of December 31, 2016 and 2015:
| (In Millions)
| December 31,
| 2016 |  | 2015
Environmental | $ | 2.8 |  |  | $ | 3.6 |
Mine closure |  |  |
U.S. Iron Ore 1 | 187.8 |  |  | 214.0 |
Asia Pacific Iron Ore | 16.2 |  |  | 16.4 |
Total mine closure | 204.0 |  |  | 230.4 |
Total environmental and mine closure obligations | 206.8 |  |  | 234.0 |
Less current portion | 12.9 |  |  | 2.8 |
Long-term environmental and mine closure obligations | $ | 193.9 |  |  | $ | 231.2 |
1 U.S. Iron Ore includes our active operating mines, our indefinitely idled Empire mine and a closed mine formerly operating as LTVSMC.
Asset Retirement Obligations | The following represents a roll forward of our asset retirement obligation liability for the years ended December 31, 2016 and 2015:
| (In Millions)
| December 31,
| 2016 |  | 2015
Asset retirement obligation at beginning of period | $ | 230.4 |  |  | $ | 165.3 |
Accretion expense | 14.0 |  |  | 7.7 |
Remediation payments | (2.2 | ) |  | — |
Exchange rate changes | (0.2 | ) |  | (1.1 | )
Revision in estimated cash flows | (38.0 | ) |  | 58.5 |
Asset retirement obligation at end of period | $ | 204.0 |  |  | $ | 230.4 |

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- 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
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