on Btu content. EIA’s data—originally allocated to Btu ranges for coal supply and demand modeling—had been used to approximate the ERR by coal rank in the early 1990s. Over time, the small differences between resources and reserves by coal rank and by Btu ranges became significant due to cumulative depletion adjustments. The January 1, 2006, data include internal additions to coal tonnages by Btu ranges to identify the coal ranks where more than one rank occurs in borderline resource areas and to unify the tonnage totals. Recoverable coal reserves at producing mines represent the quantity of coal that can be recovered (i.e., mined) from existing coal reserves at reporting mines.
EIA’s ERR include the coal in the DRB considered recoverable after excluding coal estimated to be unavailable due to land use restrictions or currently economically unattractive for mining after applying assumed mining recovery rates.
The effective date for the DRB, as customarily worded, is “Remaining as of January 1, 2006.” These data are contemporaneous with the RRPM, customarily presented as of the end of the past year’s mining—in this case, December 31, 2005. Current or recent mining in a state does not imply those data for a DRB and ERR.
The DRB includes publicly available data on coal mapped to measured and indicated degrees of accuracy and found at depths and in coalbed thicknesses considered technologically minable at the time of determinations.
All reserve expressions exclude silt, culm, refuse bank, slurry dam, and dredge operations. RRPM excludes mines producing less than 10,000 short tons, which are not required to provide reserves data.
SOURCES: EIA Form EIA-7A, Coal Production Report; MSHA, Form 7000-2, Quarterly Mine Employment and Coal Production Report; and EIA estimates.