Tribal groups and environmental activists claimed today that “irresponsible” practices in the mountains of Benguet province has caused “the worst mining disaster in the last two decades.” An independent fact-finding mission conducted by environmental group Kalikasan reported that "massive silt deposits and probable toxic contamination" were registered in the Agno River and its tributaries. The report said 20.6 million metric tons of mine waste were released into the waterway following a leak from a tailings pond belonging to the Philex Mining Corporation. Tribal groups today joined members of Kalikasan in a march in Manila’s Ortigas business district to demand payment "for all the immediate and long term environmental and social costs" the company has incurred. Clemente Bautista, national coordinator of Kalikasan, said the "massive amount of silt" in the river has badly affected aquatic ecosystems. "There’s no skirting the fact that Philex is entirely responsible, and must not only pay for full ecological restoration of the affected environment, but also the indemnification of the affected communities," he said. Kakay Tolentino, spokesperson for the indigenous people's group Katribu, said "Philex Mining cannot deny that its irresponsible mining practices caused the disaster." The group called on the mining company to immediately close its tailings pond and consider closing its operations in Benguet province. The Mines and Geosciences Bureau earlier warned Philex Mining that it might lose its environmental compliance certificate, a basic requirement for any business, because of alleged violations of the country’s clean water laws. Related reports: Urgent call for probe into toxic spill