There is a growing awareness to the environmental threats posed by the abandoned mines that are scattered in the country today. As most of these mines were developed long before the enactment of the Philippine Mining Act and current environmental legislations, casual efforts were only initiated, if any, by the operators before they totally abandoned the area. Without appropriate management interventions, these mines were left to pollute vital waterways, such as heavy metals released from underground and surface mine workings, acid mine drainage from the reaction of exposed pyrites and sulphide materials present in the natural environment, and siltation due to exposed mine-out areas, among other environmental problems. Unrestricted access to degraded mine structures nearing collapse and neglected tailings ponds also remain constant risk to nearby communities.
The Government through the Mines and Geo-Sciences Bureau aims to address these environmental threats and a safety hazard posed by the abandoned mines and is now conducting an assessment of identified potential areas for mine rehabilitation.
Of the few abandoned mines in Region IX that operated under the auspices of the old mining act, Zambales Base Metals (ZBM) situated at Upper Baluno was selected for the rehabilitation project. Though the area covered by the company for its copper mine operation may appear to be quite smaller compared to other modern day mine operations within the Zamboanga region, the impact of abandoned mines can be profound and may last for many generations. Thus there is an urgent need to assess the extent of the impacts caused by previous operation of ZBM, to evaluate the structural integrity of the abandoned mine workings, and come up with sound mitigation programs.
On 2007, the MGB Regional Office conducted an initial risk assessment of the old ZBM mine using an adopted checklist rating the risks on 6 impact categories-(1) Assessment for Acid Mine Drainage (2) Assessment of Safety Hazard (3) Assessment for Impact on Vegetation (4) Assessment of Erosional Hazard (5) Assessment of Visual Intrusion and (6) Assessment of Heritage Value. The risk assessment report was forwarded to Central office for inclusion on the possible list for mine rehabilitation.
On September 2017, technical personnel from the MGB Central Office together with the regional counterparts revisited the old ZBM mining project. This is for the purpose of doing the reconnaissance survey as an initial step to the objective of rehabilitating the mine affected areas. The sites visited were the old tailings pond, mine derelict structures, ruins of the copper processing plant, and underground mine workings. The findings of the assessment shall be the basis of the recommendation to include ZBM in the priority list of abandoned mines to be rehabilitated in the country.
The next step would be the second phase of the risk assessment of the old mining project which is scheduled on 2018. This activity aims to quantity the levels of risks of the abandoned structures using accepted methodologies, assessing the likelihood and consequences of such incidents, and managing risks by the development of a sound mine rehabilitation plan.