The Office of the Mines and Geosciences Bureau (MGB) -Region III, prior to its creation as a regional center, was a mere Mineral District under Region IV in Quezon City. It was named Mineral District No III, which was created by virtue of Mines Administrative Order No. MRD 46, Series of 1985 that called for the creation of mineral districts in the different regional offices of the then Bureau of Mines and Geosciences (BMG).
The then BMG’s Mineral District No. III Office was located in Barangay Dolores, San Fernando Pampanga. It was manned by six (6) personnel headed by Mr. Randolph Discipulo, a mining engineer whose works ranged from recording, filing, and transmitting official papers to BMG Region IV in Quezon City. BMG Regional Office No. IV that was under the Ministry of Natural Resources (MNR), on the other hand, was organized in October 1978.
Pursuant to Section 15 of Executive Order No. 192 dated June 10, 1987, the MNR was reorganized into the now Department of Environment and Natural Resources (DENR). The BMG, on the other hand, was transformed into a staff bureau and was renamed to MGB.
Under the said 1987 DENR reorganization, the MGB absorbed the staff functions of the BMG and Mineral Resources Development Board (MRDB). The line functions of BMG were absorbed by the respective regional offices of the DENR. Consequently, the MGB-Regional Office No. III 3 was then called as the ‘Mines and Geosciences Development Service” or MGSDS, which was as one of the five (5) Service Offices of the DENR-Regional Office No. III in the Central Luzon Region.
Under the said organizational set-up, the MGSDS, which was headed by a Regional Technical Director (RTD), had two (2) technical divisions. namely: Mining Services and Mineral Lands Management; and the Geology Division. It was fully operationalized on January 2, 1989 when most of the assigned personnel officially reported for duty.
With the passage of the Philippine Mining Act of 1995, the MGB together with its regional offices was transformed into a line bureau. Each Mines Regional Office is now headed by a Regional Director and has four (4) divisions, namely: Administrative and Finance; Mine Management; Mining Environment and Safety, and Geology.
As regards area jurisdiction, MGB Regional Office No. III now covers the seven provinces of Bulacan, Bataan, Nueva Ecija, Pampanga, Tarlac, Aurora and Zambales; and the five cities of Angeles, Cabanatuan, Olongapo, Palayan, and San Jose.