; (BB) ensuring compliance with the requirements of this Act with regard to the employee’s performance of such labor; or (CC) upholding the rights and protections of this Act with regard to the employee’s performance of such labor; or (dd) based on an act or omission of the 2 or more persons, the employee reasonably believed that such persons were the employee’s employers and the employee did not have actual knowledge that any of the persons were not the employee’s employer under this Act. . (d) Federal Mine Safety and Health Act of 1977 The Federal Mine Safety and Health Act of 1977 ( 30 U.S.C. 801 et seq.), as amended by paragraphs (1) and (2) of section 102(d), is further amended by inserting after section 4A the following: 4B. Applicability to multiple employers and related entities (a) Multiple employers (1) Rule of interpretation This subsection— (A) is to be read as an addition to, and an augmentation and expansion of, all relevant judicial and agency interpretations in existence on the date of enactment of the Worker Flexibility and Small Business Protection Act of 2020 regarding which persons qualify as operators in relation to a given miner under this Act, including in a multiple employer or joint employment structure; (B) shall not be interpreted by any court or agency as a restriction on, or narrowing of, any such interpretations