KASIBU, Nueva Vizcaya—When miners extract ore from underground using the old-fashioned way, tunnels create void spaces underneath which poses the threat of ground subsidence in the future.
To prevent ground subsidence and other issues, Oceanagold—the operator of the Didipio gold-copper mine here—introduced its revolutionary “paste backfill” technology, the first of its kind in the Philippines.
“As the Didipio gold-copper mine begin its shift this year to purely underground mining, the multi-million-dollar revolutionary paste backfill plant will take the center-stage,” General Manager David Way of Didipio Operations said.
Didipio operation will utilize mine tailings or slurry from the processing plant as a material to fill gaps or voids left when ore is extracted underground.
The filling material, which is made up of sand-like ground rocks mixed with a special cement designed for the purpose, will completely harden in about 22 days after application.
To convert a wet slurry into a paste backfilling material, a long rolling flatbed was designed to reduce the moisture content of mine tails disposed by the gold-copper mill, then upon achieving the right moisture level, it will be mixed with cement and pumped back underground to fill gaps and access tunnels which are no longer in use.
Effective paste backfills eliminate the problem on flooding of tunnels as this would close crevices where groundwater flow, a mining engineer explained.
“It is part of our commitment to responsible mining. Present legacy mines in the country have faced incidents of ground subsidence decades after these were closed. We make sure this will not happen in Didipio,” Way added.