43 C.F.R. § 3481.4-2
What are some examples of circumstances that qualify for a temporary interruption of coal severance?
(a) Movement, failure, or repair of major equipment, such as draglines or longwalls; overburden removal; adverse weather; employee absences;
(b) Inability to sever coal due to orders issued by governmental authorities for cessation or relocation of the coal severance operations; and
(c) Inability to sell or distribute coal severed from the lease or LMU out of or away from the lease or LMU.