On July 26, 1991, the State Tax Department filed Legislative Regulations for the appraisal of producing coal properties and producing other mined mineral properties (See §§ 110 CSR 1I-1 and 1K-1 et seq.). This notice will address these regulation's use of the in-place tonnage per acre-foot for producing coal properties, referenced in § 110 CSR 1I-3.30 and for other mined mineral properties, referenced in § 110 CSR 1K-3.27.

DISCUSSION

The specific gravity¹ of bituminous coal ranges between 1.15 and 1.5 depending on rank, moisture content, and ash content, and averages 1.32. The regulatory equation for the determination of tons per acre-foot is as follows:

62.4 lbs water per ft3 water	X	43,560 ft3 per acre-ft.	X	natural resource specific gravity
2000 lbs/ton					= tons per acre-ft.

Substituting the specific gravity of coal into the formula we find that there are approximately 1800 tons of coal in place per acre-foot as follows:

62.4 X 43,560 X 1.32 =	1,793.97 or 1800 tons per acre-ft.
2000

 

It should be noted here that the 1800 tons per acre-foot establishes a benchmark for determination of a recovery rate. If the specific gravity of coal being mined is less than or greater than 1.32 then the recovery rate per acre mined should be adjusted accordingly, thus eliminating the potential of inaccurate calculations of acres mined.

 Similar calculations for other mined minerals yield the following results:

Limestone Sandstone Clay/Shale Sand/Gravel Salt

= = = = =

3600 acre-ft. 3600 acre-ft. 3050 acre-ft. 2400 acre-ft. 2950 acre-ft.

For more information concerning the development of the in place tonnage of natural resource properties see §§ 110 CSR 1I-1 and 1K-1 et seq. or contact the State Tax Department at (304) 558-3940.

Issued: January 29, 1999	Joseph M. Palmer State Tax Commissioner West Virginia State Tax Department
State Tax Department Property Tax Division P.O. Box 2389 Charleston, WV 25328-2389	Operator on duty 8:30 am - 4:30 pm Monday through Friday Phone: (304) 558-3940 Fax: (304) 558-1843

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¹specific gravity - The ration of the weight of an object in air to the weight of an equal volume of water