W. Va. Code § 11-13BB-7: Forfeiture of unused tax credits.

Disposition of property or cessation of use. -- If during any taxable year, property with respect to which a tax credit has been allowed under this article:

(1) Is disposed of prior to the end of the fourth tax year subsequent to the end of the tax year in which the property was placed in service or use; or

(2) Ceases to be used in a coal mine of the eligible taxpayer in this state prior to the end of the fourth tax year subsequent to the end of the tax year in which the property was placed in service or use, then the unused portion of the credit allowed for such property is forfeited for the tax year in which the disposition or cessation of use occurred and all ensuing years.