MANILA - Manila Mining Corporation (MMC) said there is no law or regulation requiring it to treat acidic water in its open pit mines.

TV Patrol and ANC aired a report by ABS-CBN's Carolyn Bonquin on Tuesday saying Environment Secretary Gina Lopez gave MMC two months to neutralize the acidity level of the water in its open pits in its Ntina mine in Placer, Surigao del Norte.

Lopez had expressed concern that the open pit might overflow and contaminate the surrounding waters.

But according to MMC, since the open pit contained copper and other minerals, it was natural for the water there to become acidic. The company also insisted that there was no law obliging mines to neutralize the acidic water in contained pits.

TV Patrol reported that one pit in MMC's Ntina mine had a 2.8pH acidity level, which was far from the neutral level of 7.0pH.

But MMC said a team from the Department of Environment and Natural Resources (DENR) went to the mine site in Placer a day before Lopez's visit on April 18 and tested the water quality from its discharge points to coastal waters.

"Results show water quality ranging from 7.27pH to 8.89pH which are within the DENR standard of between 5.5pH and 9.5pH. This clearly shows that MMC is compliant with DENR standards," MMC said in a statement sent to ABS-CBN on Wednesday.

MMC further claimed that an earlier test in February 27 also showed that the quality of the water in its open pits was compliant and within DENR standards.

"Outside of the two special tests instructed by Secretary Lopez, a Multi-Partite Monitoring Team (MMT) conducts water sample testing on a regular basis and MMC has always been found to be compliant. The MMT is composed of representatives from MMC, DENR, EMB, MGB, LGUs, church, and NGOs," the mining company said.

MMC is not operating its mine right now as it awaits the DENR's approval of its application for an Environmental Compliance Certificate.