Philex completes Boyongan mine study

PHILEX Mining Corp. on Wednesday announced the completion of the In-Phase Mine Plan feasibility study and an updated mineable reserve estimate for the Boyongan deposit.

This latest development is in accordance with the 2012 Philippine Mineral Reporting Code.

In 2019, a feasibility study for a 4 million tons per year sublevel cave mining plan for the Boyongan copper porphyry deposit was completed and was then used as the basis for the In-Phase Mine Plan feasibility study. According to Philex, the in-phase plan consists of a starter sublevel cave mine that has an annual ore production of 700,000 tons or 2,000 tons per day, noting that mining will commence at the East sublevel cave because it has the highest-grade ore.

Also, the mining firm said that a new decline will be developed to access the East sublevel cave while the existing exploration decline will be rehabilitated to serve as an alternative mine access and a ventilation exhaust.

As the ore currently consists of predominantly oxide minerals, Philex said that copper, gold and silver will be recovered using copper leaching and gold leaching processes. The processing plant will produce a London Metal Exchange grade (99.999 percent) copper cathode and gold-silver ore.

Philex said that the initial capital cost to develop the starter mine is estimated to be $224 million, which will be spent within the 2.5 years development period.

“The 2,000 tons per day starter mine will last for five years, after which in the sixth year of production, mining and processing rate will increase to 4,000 tons per day or 1.3 million tons per year. By the ninth year, ore production and processing rates will again increase to 8,000 tons per day or 2.7 million tons per year,” said Philex.

This year, a copper flotation circuit will be added to the process plant as the ore mine now consists of oxide and sulfide minerals, which will produce copper concentrates with gold and silver. The final ramp up will occur in the twelfth year.

Ore production rate starting this year up to when the mineable ore will be exhausted will be 12,000 tons per day or 4 million tons per year. The life of mine for Phase 1 Boyongan is 28 years.

After incorporating standard mining factors to the mineral resource, the feasibility study has delineated 81 million tons as a mineable reserve.