Can you imagine using clean water that’s already been used in a mining operation? In Didipio, Nueva Vizcaya, this is possible because of OceanaGold Philippines’ (OGPI) innovations.
Extractive industries like mining require large amounts of water to process mineral products. OGPI is taking the lead in using clean and sophisticated technologies, making it one of the best in the world in terms of water management.
“In 2016, the company recycled an average of 75% of the process plant’s water requirements. We reduced abstraction of water from local catchments and overall operating costs. As of December 2018, our continuous efforts to improve the water recycling rate resulted in an increase of 90%,” David Way, OGPI General Manager noted.
The company has a PHP 268 million (USD 6.1 million) water treatment plant (WTP), where water from tailings storage facilities (TSF) go through before being discharged to the receiving water body. This WTP has an operating cost of PHP 6.38 million (USD 128,000) per year and has a treatment capacity of 1,980 m3 per hour.
Non-toxic tailings dam
The Didipio Mine is among the 10% of mining companies in the world that does not use cyanide and mercury in gold processing. Therefore, the resulting tailings stored in the tailings dam is non-toxic and non-hazardous to the surroundings. The design of the mine’s Tailing’s Storage Facility (TSF) maintains a robust dam wall capable of containing the mill tailings in a mountainous terrain which experiences rainfall up to 3,000 mm per year.
To meet international engineering standards, the tailing’s dam foundation was stripped of all alluvial material down to base rock and keyed in to reduce seepage. Based on the bathymetric survey conducted in June 2018, the actual volume impounded is 12,572,851 cu.m. This is 34.5% of the TSF’s design volume capacity which is 36,351,006 cu.m.
Fish that thrives in the TSF is one biological evidence of the water’s non-toxicity. There are also migratory birds and wild ducks that prey in the area.
Surface water management
At the mine, separate drain systems were created to intercept mine runoff from haul roads and slopes; drains for clean water runoff from seeps and streams. Mine water is then diverted towards sediment ponds before being discharged into the environment, while clean water is channeled directly towards the river.
OGPI aims to minimize surface water runoff in the Didipio Mine as this reduces pumping costs; decreases risk of slope failure; improves mine safety and production; and maximizes clean water that goes to rivers.
“OGPI is an environmentally and socially responsible community member. We only use world-class technologies to ensure the safety and efficiency of our operations. Rest assured, we will continue to operate with the highest levels of safety and cleanliness, and with the benefit of our community in mind,” Way concludes.
In addition, the Didipio Mine’s environment team strictly implements washing only on designated vehicle wash bays equipped with oil and water separators. Water quality monitoring and maintenance are being conducted regularly to ensure efficiency of oil and water separator.
Sharing the technology
Recently, OGPI began collaborating with the International River Foundation (IRF) to bring coaching and mentoring to community members, leaders and regulators to help improve water quality in Didipio. It also partnered with the Isabela State University (ISU) and the Quirino State University (QSU) to conduct a study on the Integrated Watershed Management of Addalam Basin and to establish a Biodiversity Reservation Area.
Recognizing the significance of water to its operation and its surrounding communities, the Company is currently constructing the Didipio Water System Project which includes water storage, treatment and supply infrastructure. This will ensure potable water supply to each household and other institutions within the Didipio community. On completion, the system will have the capacity to provide water for up to 11,000 individuals or about 2,400 households.