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ASSET RETIREMENT OBLIGATIONS (Tables) | 6 Months Ended
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Jun. 30, 2019
ASSET RETIREMENT OBLIGATION |
Summary of Asset Retirement Obligation | The following table summarizes the changes in the reserve for future restoration and reclamation costs on the balance sheet:
|  | June 30, |  | December 31,
(thousands of dollars) |  | 2019 |  | 2018
Balance, beginning of period |  | $ | 6,203 |  | $ | 5,731
Liabilities settled |  |  | (320) |  |  | (521)
Liabilities disposed |  |  | (13) |  |  | —
Accretion expense |  |  | 156 |  |  | 993
Balance, end of period |  |  | 6,026 |  |  | 6,203
Less: Current portion |  |  | (881) |  |  | (708)
Non-current portion |  | $ | 5,145 |  | $ | 5,495

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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://fasb.org/us-gaap/role/ref/legacyRef -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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