There is established in the Department of Labor a Mine Safety and Health Administration to be headed by an Assistant Secretary of Labor for Mine Safety and Health appointed by the President, by and with the advice and consent of the Senate. The Secretary, acting through the Assistant Secretary for Mine Safety and Health, shall have authority to appoint, subject to the civil service laws, such officers and employees as he may deem necessary for the administration of this Act, and to prescribe powers, duties, and responsibilities of all officers and employees engaged in the administration of this Act. The Secretary is authorized and directed, except as specifically provided otherwise to carry out his functions under the Federal Mine Safety and Health Act of 1977 [30 U.S.C. 801 et seq.] through the Mine Safety and Health Administration.