The environmental management and protection systems for the Canatuan Project include the implementation of widespread structural erosion control measures, construction of tailings management facilities, water quality monitoring and management, and reforestation.
Tailings management
The 44-metre high Gossan Tailings Dam has a total storage capacity of 504 million litres or approximately 800,000 tonnes of gossan ore tailings. Cyanide detoxification is conducted intermittently to balance the water levels within the gossan impoundment and to maintain sufficient freeboard for storm events. Natural cyanide degradation is used to the maximum extent possible to reduce cyanide levels in the tailings water. Chemicals are then added to the excess water to reduce the cyanide concentrations to regulatory limits. Onsite laboratory testing is done prior to release of any water to ensure full regulatory compliance.
Soil erosion and erosion management
Restoration and protection measures are implemented for both the disturbed and non disturbed areas within the mining operations areas. Extensive use and placement of natural abaca netting on the reshaped areas is being done to reduce erosion and better facilitate the re-vegetation program. Where soil losses were unavoidable, sediment ponds are constructed around the perimeter of the disturbed areas. Sediment collected within these ponds is periodically removed and stockpiled for future topsoil cover and re-vegetation activities. The ponds themselves are constructed of reinforced earth structures that are flexible and can easily be removed, relocated and planted to blend within the natural topography and vegetation.
Reclamation & rehabilitation programs
Tree, shrub and grass planting activities assist the natural reforestation process. Approximately 60,000 trees have been planted within and around the MPSA area. Multiple species are used to enhance the bio-diversity and improve the restored wildlife habitat. These include mangium, gmelina, mahogany, narra, rubber and bamboo. Native grasses and low shrubs are also planted to improve soil stability and provide lower undergrowth vegetation zones. Approximately 50 hectares within the MPSA area have been replanted and are undergoing active reforestation.
The supply of seedlings, root stock and grasses are provided by the TVI nursery located onsite and by private nurseries within the local communities. The TVI nursery facilities continue to expand to serve the increased planting programs. TVI has also initiated employment of local residents to collect native grass and other vegetation seeds for broadcast and planting.
Water Quality Monitoring
Daily, weekly and quarterly water quality monitoring of the tailings impoundments, streams and rivers continues on an ongoing basis. Seventeen long term monitoring stations are sampled on a quarterly basis by a multi-partite monitoring team headed by the Philippine Mines and Geosciences Bureau. Results of the sampling and laboratory testing programs indicate that the water quality continues to meet the regulatory and permit conditions.
Annual Environmental Monitoring Programs
In addition to the programs above, TVIRD implements four environmental monitoring programs: aquatic resources monitoring, air quality testing, noise monitoring, and terrestrial flora and fauna monitoring.
Mine Rehabilitation
One of the company’s goals is to return the Canatuan Mine to its natural and stable state, thereby making it available to the Subanons for other uses. TVIRD has been looking at mine reclamation techniques that can be applied to Canatuan at the end of the mine life. Decisions on the final rehabilitation and reclamation plan, however, will be made once the company has gathered sufficient data and once consultations have been made with the Subanon as part of the Ancestral Domain Sustainable Development and Protection Plan.
