OceanaGold (Philippines), Inc. has made substantial gains in its progressive rehabilitation by adopting an innovative and pioneering approach branded as the “Harmony in Diversity (HiD) Effect.” Progressive Rehabilitation, as defined by the Mines and Geosciences Bureau, is a cost-effective engineering and biological approach to mine rehabilitation. It aligns with the approved post-mining land use and should be implemented throughout all stages of mining to support ecosystem recovery and biodiversity regeneration.
HiD has significantly reduced OGP’s1 or USD63,000 per hectare in 2023 to just PHP1.3 million or USD23,000 per hectare in 2025. The decrease is attributed to shifting away from hydroseeding, a conventional rehabilitation method that relied on imported mulch which is a material used to enrich the soil, and fast-growing grass seeds that required frequent trimming and costly maintenance.
Beyond cutting costs, the initiative has also created a positive impact by allowing the budget originally allocated under traditional rehabilitation processes to be maximized. The savings can now be reallocated to other environmental programs of the Company, strengthening its overall environmental stewardship efforts.
The HiD Effect successfully combines four distinct methods in rehabilitation: Miyawaki Method from Japan, Zai Pit Technique from Burkina Faso, Mycorrhiza fungi introduction for soil nutrition, and the use of decomposing twigs or trees to help create mini-ecosystems for bacteria and fungi. The approach mimics the original ecosystem of an area using the natural symbiotic relationship of different plants and species which were found endemic to the land before the mining operations.
First implemented in the second quarter of 2024, the HiD Effect is ahead of the Memorandum Order No. 2025-001 issued by the Mines and Geosciences Bureau (MGB) in February 2025 to leverage the natural succession process in which ecosystems recover over time through the sequential establishment of plant and animal species.
“Through the HiD Effect, we can transform a disturbed mining area into a self-sustaining forest in just three to five years which used to take at least 15 years under the conventional method,” Donna Del Moro, OGP’s Acting Superintendent for Environment, said.
Owing to HiD Effect’s success, the Company is already in discussions with the Ecosystem Research and Development Bureau (ERDB), the principal research agency of the Department of Environment and Natural Resources (DENR), to conduct further research in order to develop a successful rehabilitation criterion to be recommended in the rest of the mining industry. ERDB, together with the MGB, visited the Didipio Mine last April 2025 as part of a nationwide assessment of progressive rehabilitation practices.
“We value the opportunity to collaborate with DENR’s principal research arm, combining their institutional knowledge with our on-the-ground innovation,” Nericel Langres-Daulayan, OGP’s Mine Environmental Protection and Enhancement Office Manager, said.
Traditional mine rehabilitation is labor-intensive, typically requiring hydroseeding, direct seeding, assisted natural regeneration, and costly slope stabilization. Mature forest species, which are essential to replicate natural ecosystems, are often introduced much later, prolonging the recovery timeline. By contrast, the HiD Effect allows forest layers to develop simultaneously. This creates faster biodiversity recovery, enriched soil nutrients, and conditions for fauna such as birds, insects, and other wildlife to return sooner.
Based on OGP’s monthly monitoring, endemic birds such as pacific swallows, swiftlets, and wagtails have been spotted in the rehabilitated area.
“We have also observed native plants from other areas growing naturally in the rehabilitated area without our intervention, which indicates that animals are already helping spread seeds and rebuild the ecosystem. With richer biodiversity and improved water retention, we also expect these rehabilitated areas to strengthen natural defenses against erosion and landslides during heavy rains,” Del Moro added.
As of June 2025, OGP has successfully regenerated 16% or 55 hectares of the disturbed 345 hectares of the mine. The Company has approximately spent USD 2.5 million since 2013 for its progressive rehabilitation.
“OceanaGold is committed to leaving a positive legacy by proving that responsible mining includes not just resource development but also regenerative ecosystem renewal. The HiD Effect ensures that post-mining areas can thrive and sustain communities for generations to come,” Langres-Daulayan added.
