Va. Code § 58.1-3287
Notwithstanding § 58.1-3286, whenever there is a general reassessment of real estate in any county or city, mineral lands and minerals shall be included in the general reassessment, but shall be separately assessed from other real estate, and the assessor or assessors shall be governed by the provisions of § 58.1-3286 in making the assessment. Taxes for each year on the mineral lands and minerals assessed under this section shall be extended by the commissioner of the revenue on the basis of the last general reassessment made prior to such year, subject to such changes as may be made by him in performing his annual duties under § 58.1-3286. In performing such annual duties he shall adjust the assessed values in such manner as to reflect such changes as may have occurred during the preceding year, especially such changes as may have operated to increase or decrease (i) the area and the value of such portion of each tract as is improved and under development, (ii) the value of the improvements upon each tract, and (iii) the area and value of such portion of each tract as shall not be under development.
Every county in which there are mineral lands shall have a general reassessment of real estate in the year prescribed by law, even though the greater part of the area of the county consists of mineral lands.
The Department shall render advisory aid and assistance of a technical nature to the assessor or assessors, in making a general reassessment of mineral lands and minerals, upon request of the governing body of the county or city, or to the commissioner of the revenue, upon his request, provided moneys are available to the Department to defray the cost thereof.
Va. Code § 58.1-3287