Other Potential Use of Credit
Surety Bonds and Letters of Credit
The Company is required by various state and federal laws to provide security with regard to its obligations to pay workers' compensation, reclaim lands used for mining by the Company's former coal operations and satisfy other obligations. As of December 31, 2006, the Company had outstanding surety bonds with third parties totaling approximately $45.2 million that it has arranged in order to satisfy various security requirements. Most of these bonds provide financial security for obligations which have already been recorded as liabilities. Surety bonds are typically renewable on a yearly basis; however, there can be no assurance the bonds will be renewed or that premiums in the future will not increase.
If the remaining surety bonds are not renewed, the Company believes that it has adequate available borrowing capacity under its Letter of Credit Facility and its Revolving Facility to provide letters of credit or other collateral to secure its obligations.
The Company has issued letters of credit of $141.3 million under its $150 million Letter of Credit Facility, described in "Debt" above. At December 31, 2006, all of these issued letters of credit were used to secure the Company's obligations.

