Mining town gets P37-M water project

By on January 7, 2019

THE fast-growing population in the upland mining village of Didipio in Kasibu town, Nueva Vizcaya, has prompted OceanaGold to provide it with a P37-million water system.

The Didipio community has a population of about 4,000 individuals and an estimated 900 households. The natural spring water is the main source of the community’s drinking water as outlined in OceanaGold’s 2017 Mine Rehabilitation Fund Committee report, Water Resource Study for Barangay Didipio.

With this, OceanaGold, which operates the Didipio Mine, is working with the community for the construction of the P37-million Didipio Water System Project (DWSP) due for completion in 2019, Manila Times reported.

David Way, OceanaGold general manager, said the DWSP includes water storage, treatment and supply infrastructure that would provide the community with safe, potable water.

He said the system would have the capacity to provide water for up to 11,000 individuals or about 2,400 households.

“It has been our commitment to work with host communities, government and other stakeholders to address concerns around the mine’s impact on water, local challenges with water access and use, and how we can contribute to better watershed management,” Way said.

He also explained that while the nature of the mined ore at Didipio allows for extraction using grinding and flotation processes with water, they do not use cyanide or mercury for gold and copper recovery.

He said regular mine tours are conducted where visitors are allowed to walk through during grinding and floatation, where the mined ore is ground to very fine particles to separate the gold and copper from the waste material or mine tailings.

The mine tailings generated from the processing plant are stored at the tailings storage facility (TSF) while the water from the TSF is further processed in the water treatment plant, which is an automated facility, Way explained.

He said that using a flocculation and coagulation process, the water storage plant significantly reduces total suspended solids to 70 parts per million (ppm), well below the government standard for Class D water at 150 ppm.

“We also built a paste-backfill plant where approximately 30 to 40 percent of the mine tailings are mixed with cement and used as backfill material for the underground voids, which reduces the volume of tailings delivered to the TSF,” he added.

The Didipio Mine also undertakes a quarterly Toxicity Characteristic Leaching Procedure at the TSF to measure solids and naturally occurring heavy metals in the water and samples are tested by a government-accredited laboratory.

Didipio’s TSF is constructed to standards that exceed Philippine guidelines and meet International Commission on Large Dams (Icold) guidelines, and the Category High C Australia National Committee on Large Dams (Ancold) guidelines.

According to Engineer Mario Ancheta, Mines and Geosciences Bureau (MGB) Region 2 (Cagayan Valley) director, they conduct a quarterly audit of the TSF and engineers from GHD supervise all construction.

In addition, Ancheta said, Engineering Geology Ltd., an independent third party, also conducts an annual review of TSF construction to ensure it continues to meet the Icold and Ancold design criterion.

The Didipio Mine also minimizes the use of freshwater resources by recycling process water.

“Data from 2014 to mid-2018 shows we have recycled an average of 87 percent of processed water. Since we commenced commercial production, we have consistently increased the amount of water that recycled in the process plant,” Way said.

This year, he said the Didipio Mine successfully commissioned the Didipio Water Recycling and Purification Plant, which treats sewage water and maximizes recycling of water resources at the mine site.

“The [Didipio] operations conduct daily, weekly, monthly and quarterly water quality monitoring in line with all the requirements of the Department of Environment and Natural resources,” Way added.

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