Income Taxes	6 Months Ended
Nov. 30, 2011
Income Taxes [Abstract]
Income Taxes	8. Income Taxes Income taxes for the interim periods ended November 30, 2011 and November 30, 2010 have been included in the accompanying financial statements on the basis of an estimated annual rate. The tax rate differs from the 35% federal statutory corporate rate primarily due to percentage depletion that is tax deductible, state income taxes and valuation allowances against deferred tax assets. The estimated annualized rate does not include the tax impact of the loss on debt retirements which was recognized as a discrete item in the six-month period ended November 30, 2010. The estimated annualized rate excluding this charge is 3.0% for fiscal year 2012 compared to 41.0% for fiscal year 2011. We received income tax refunds of less than $0.1 million and made income tax payments of $0.1 million in the six-month period ended November 30, 2011. We received income tax refunds of $0.2 million and made income tax payments of less than $0.1 million in the six-month period ended November 30, 2010. Net deferred tax assets totaled $15.7 million at November 30, 2011 and $15.0 million at May 31, 2011, of which $13.7 million at November 30, 2011 and $12.3 million at May 31, 2011 were classified as current. Management reviews our deferred tax position and in particular our deferred tax assets whenever circumstances indicate that the assets may not be realized in the future and would record a valuation allowance unless such deferred tax assets were deemed more likely than not to be recoverable. The ultimate realization of these deferred tax assets depends upon various factors including the generation of taxable income during future periods. The Company's deferred tax assets exceeded deferred tax liabilities as of November 30, 2011 primarily as a result of the recent losses. Management has concluded that the sources of taxable income we are permitted to consider do not assure the realization of the entire amount of the increase in our net deferred tax assets expected during the year. Accordingly, a valuation allowance is required due to the uncertainty of realizing the deferred tax assets. The amount of income tax we pay is subject to ongoing audits by federal and state authorities which may result in proposed assessments. We adjust reserves for our uncertain tax positions due to changing facts and circumstances, such as the closing of a tax audit, judicial rulings, refinement of estimates, or realization of earnings or deductions that differ from our estimates. To the extent that the final outcome of a matter differs from the amount recorded, such difference generally will impact our provision for income taxes in the period that includes its final resolution. We have no significant reserves for uncertain tax positions including related interest and penalties. In addition to our federal income tax return, we file income tax returns in various state jurisdictions. We are no longer subject to income tax examinations by federal or state tax authorities for years prior to 2007.

Income Taxes

6 Months Ended

Nov. 30, 2011

8. Income Taxes

Income taxes for the interim periods ended November 30, 2011 and November 30, 2010 have been included in the accompanying financial statements on the basis of an estimated annual rate. The tax rate differs from the 35% federal statutory corporate rate primarily due to percentage depletion that is tax deductible, state income taxes and valuation allowances against deferred tax assets. The estimated annualized rate does not include the tax impact of the loss on debt retirements which was recognized as a discrete item in the six-month period ended November 30, 2010. The estimated annualized rate excluding this charge is 3.0% for fiscal year 2012 compared to 41.0% for fiscal year 2011. We received income tax refunds of less than $0.1 million and made income tax payments of $0.1 million in the six-month period ended November 30, 2011. We received income tax refunds of $0.2 million and made income tax payments of less than $0.1 million in the six-month period ended November 30, 2010.

Net deferred tax assets totaled $15.7 million at November 30, 2011 and $15.0 million at May 31, 2011, of which $13.7 million at November 30, 2011 and $12.3 million at May 31, 2011 were classified as current. Management reviews our deferred tax position and in particular our deferred tax assets whenever circumstances indicate that the assets may not be realized in the future and would record a valuation allowance unless such deferred tax assets were deemed more likely than not to be recoverable. The ultimate realization of these deferred tax assets depends upon various factors including the generation of taxable income during future periods. The Company's deferred tax assets exceeded deferred tax liabilities as of November 30, 2011 primarily as a result of the recent losses. Management has concluded that the sources of taxable income we are permitted to consider do not assure the realization of the entire amount of the increase in our net deferred tax assets expected during the year. Accordingly, a valuation allowance is required due to the uncertainty of realizing the deferred tax assets.

The amount of income tax we pay is subject to ongoing audits by federal and state authorities which may result in proposed assessments. We adjust reserves for our uncertain tax positions due to changing facts and circumstances, such as the closing of a tax audit, judicial rulings, refinement of estimates, or realization of earnings or deductions that differ from our estimates. To the extent that the final outcome of a matter differs from the amount recorded, such difference generally will impact our provision for income taxes in the period that includes its final resolution. We have no significant reserves for uncertain tax positions including related interest and penalties.

In addition to our federal income tax return, we file income tax returns in various state jurisdictions. We are no longer subject to income tax examinations by federal or state tax authorities for years prior to 2007.