Section 903.817 - Performance standards-Underground mining activities(a) Part 817 of this chapter, Permanent Program Performance Standards-Underground Mining Activities, applies to any person who conducts underground mining activities, except § 817.116(a)(1) of this chapter regarding revegetation success standards, for which paragraph (b) of this section substitutes.(b) Standards for success shall be those identified at § 817.116(a)(2) and (b) of this chapter. Statistically valid sampling techniques for measuring success shall be included in the mining and reclamation plan and approved by the regulatory authority.