(b) Applicable percentage. -- For the purpose of subsection (a), the applicable percentage for any property shall be determined under the following table:

If useful life is: The applicable percentage is:

4 years or more but less than 6 years. 33 1/3%

6 years or more but less than 8 years 66 2/3%

8 years or more 100%

The useful life of any property for purposes of this section shall be determined as of the date such property is first placed in service or use in this state by the taxpayer, and is the period during which the property may reasonably be expected to be useful to the taxpayer as part of a coal loading facility.

(c) Cost. -- For purposes of subsection (a), the cost of each property purchased for a coal loading facility shall be determined under the following rules:

1. (1) Trade-ins. -- Cost shall not include the value of any property given in trade or exchange for the property purchased for a coal loading facility.
2. (2) Damaged, destroyed or stolen property. -- If property is damaged or destroyed by fire, flood, storm or other casualty or is stolen, the cost of replacement property shall not include any insurance proceeds received in compensation for the loss.
3. (3) Rental property. -- The cost of property acquired by lease for a term of ten years or longer shall be one hundred percent of the rent reserved for the primary term of the lease, not to exceed twenty years. Lease renewals, subleases or assignments shall not be considered.
4. (4) Property purchased for multiple use. -- The cost of property purchased for multiple business use including use as a component part of a coal loading facility business together with some other business or activity not eligible for credit under this article shall be apportioned between such businesses or activities. The amount apportioned to the activity of loading coal shall be considered as an eligible investment subject to the conditions and limitations of this section.
5. (5) Self-constructed property. -- In the case of self-constructed property, the cost thereof shall be the amount properly charged to the capital account for purposes of depreciation.