About coal production revision estimates

EIA revises its weekly (and monthly) original estimates of state-level coal production using quarterly mine-level coal production data from the Mine Safety and Health Administration (MSHA) as soon as the data are available.  This method guarantees that EIA’s revised coal production estimates for each past quarter conform with the MSHA survey data. The state level revised estimates include refuse coal. 

EIA uses this equation to revise its weekly coal production estimates:

Revised weekly estimate (State A) =
original EIA estimate (State A) x MSHA quarterly data (State A) ÷

Sum of original EIA estimate (State A) for all weeks in the quarter

Note:  All weeks reported in the tables end on a Saturday.  The estimates for the first and last weeks in a year include estimated coal production only for the days that occurred in the year.