"Industrial property" means real and personal property integrated as a functioning unit intended for the assembling, processing and manufacturing of finished or partially finished products.
"Natural resources property" means coal, oil, natural gas, limestone, fireclay, dolomite, sandstone, shale, sand and gravel, salt, lead, zinc, manganese, iron ore, radioactive minerals, oil shale, managed timberland as defined in section two of this article, and other minerals.
In each subsequent term of the net proceeds income series, the calculation shall use the value from the previous term and multiply that term by a capitalization rate multiplier and an applicable twelve-month decline rate multiplier.
In each subsequent term of the royalty interest receipts income series, the calculation shall use the value from the previous term and multiply that term by a capitalization rate multiplier and an applicable twelve-month decline rate multiplier.
W. Va. Code § 11-1C-10