30 CFR §57.6161

1. (a)Auxiliary facilities used to store explosive material near work places shall be wooden, box-type containers equipped with covers or doors, or facilities constructed or mined-out to provide equivalent impact resistance and confinement.
2. (b)The auxiliary facilities shall be—
   1. (1)Constructed of nonsparking material on the inside when used for the storage of explosives;
   2. (2)Kept clean, suitably dry, and orderly;
   3. (3)Kept in repair;
   4. (4)Located out of the line of blasts so they will not be subjected to damaging shock or flyrock;
   5. (5)Identified with warning signs or coded to indicate the contents with markings visible from any approach;
   6. (6)Located at least 15 feet from all haulageways and electrical equipment, or placed entirely within a mined-out recess in the rib used exclusively for explosive material;
   7. (7)Filled with no more than a one-week supply of explosive material;
   8. (8)Separated by at least 25 feet from other facilities used to store detonators; and
   9. (9)Kept securely locked unless all access to the mine is either locked or attended.