30 CFR §886.20

1. (a)If there are any unexpended funds after your grant is completed, we deobligate the funds when we close your grant. We treat unused funds as follows:
   1. (1)We transfer any State share funds under § 872.14 of this chapter or Tribal share funds under § 872.17 that were not expended within three years of the date they were awarded in a grant, except five years for funds awarded in Fiscal Years 2008, 2009, and 2010, to historic coal funds, § 872.21 of this chapter. We distribute any funds transferred to historic coal in the next annual distribution in the same way as historic coal funds from fee collections during that fiscal year.
   2. (2)We hold any unused Federal expense funds under § 872.24 of this chapter for distribution to any State or Indian tribe as needed for the activity for which the funds were appropriated.
   3. (3)We make unused funds of all other types available for re-award to the same State or Indian tribe to which they were originally distributed. This includes historic coal funds under § 872.21 of this chapter, minimum program make up funds under § 872.26 of this chapter, and prior balance replacement funds under § 872.29 of this chapter.
2. (b)If you have any State share funds or Tribal share funds that were distributed to you in an annual distribution under § 872.15 or § 872.18 of this chapter but that were not awarded to you in grant within 3 years of the date they were distributed, or 5 years for funds distributed in Fiscal Years 2008, 2009, and 2010, we transfer the unawarded funds to the historic coal fund under § 872.21 of this chapter and distribute them in the next annual distribution.