PHILIPPINE MINING DEVELOPMENT CORPORATION, ATTY. LITO A. MONDRAGON, ATTY. JAIME T. DE VEYRA, ZENAIDA A. ALFONSO, AND MA. NIEVES MARIVES D. SANTOS, PETITIONERS, VS. CHAIRPERSON MICHAEL G. AGUINALDO, COMMISSIONER JOSE A. FABIA, COMMISSIONER ISABEL D. AGITO, THE COMMISSIONERS, COMMISSION ON AUDIT, RESPONDENTS