Code of Federal Regulations Title 30. Mineral Resources § 30.721.11 Extent

(a) On the basis of not less than two consecutive State inspection reports indicating a violation of the Act, regulations or permit conditions required by the Act;

(b) On the basis of information provided by a State or any person which gives rise to a reasonable belief that the provisions of the Act, regulations or permit conditions required by the Act are being violated, or that a condition or practice exists which creates an imminent danger to the health or safety of the public, or is causing or can reasonably be expected to cause significant, imminent environmental harm to land, air, or water resources;  and

(c) On a random basis of at least one complete inspection each 6 months. A complete inspection is an onsite review of the operator's compliance with all applicable standards in these regulations within the entire area disturbed or affected by mining.