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ACCRUED CAPPING, CLOSURE AND POST CLOSURE | 9 Months Ended
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Jan. 31, 2013
ACCRUED CAPPING, CLOSURE AND POST CLOSURE |
4. | ACCRUED CAPPING, CLOSURE AND POST CLOSURE
Accrued capping, closure and post-closure costs include the current and non-current portion of costs associated with obligations for closure and post-closure of our landfills. We estimate our future capping, closure and post-closure costs in order to determine the capping, closure and post-closure expense per ton of waste placed into each landfill. The anticipated timeframe for paying these costs varies based on the remaining useful life of each landfill, as well as the duration of the post-closure monitoring period. The changes to accrued capping, closure and post-closure liabilities for the nine months ended January 31, 2013 and 2012 are as follows:
|  | Nine Months Ended January 31, |
|  | 2013 |  |  | 2012 |
Beginning balance |  | $ | 39,629 |  |  | $ | 36,407 |
Obligations incurred |  |  | 2,606 |  |  |  | 2,350 |
Accretion expense |  |  | 2,653 |  |  |  | 2,510 |
Payments |  |  | (2,304 | ) |  |  | (1,298 | )
Ending balance |  | $ | 42,584 |  |  | $ | 39,969 |

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- Definition The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7569-110849 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 143 -Paragraph 22 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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