Acting CEO Scott Sullivan said the resumption of milling came two weeks ahead of schedule, following the completion of plant upgrades and maintenance activities.
Mining commenced a month earlier than expected in October.
Sullivan heralded the resumption of operations as a major milestone.
Underground operations will ramp up over the course of the next three quarters, so primary mill feed initially will be some 23 million tonnes of low-grade stockpile ore on the ROM pad that will be supplemented by higher-grade mine ore as stope development accelerates.
The Didipio plant is expected to ramp up to its throughput rate of 3.5 million tonnes per annum over the next few weeks.
The early restart of mining saw the company increase its production outlook for the mine to 7000-12,000 ounces of gold and 1000 tonnes of copper at all-in sustaining costs of US$100-150/oz after by-product sales, up from 5000-10,000oz at $300-400/oz.
The miner aims to produce 10,000oz gold and 1000t copper per month at capacity.
Didipio produced 115,000oz gold and 15,000t copper in 2018.
The all-important Financial or Technical Assistance Agreement was renewed for 25 years by the Philippines government in June.
The company has been rebuilding its workforce, almost all who were sacked in 2020 due to the shutdown.
About 90% of staff are expected to be in place by year's end.
OceanaGold produced 79,177oz at $1200/oz for the third quarter, with sales of 97,445oz, including 19,151oz of gold plus 3356t of copper sold from Didipio, from inventory gold-copper concentrate, generating $38 million in cash.
The initial 25-year FTAA permit expired in June 2019.
OceanaGold commenced the renewal process in 2018.
The mine had been operating under a temporary licence until a combination of the uncertainty and a blockade backed by the local government forced it to suspend operations in mid-2019.
The mine split opinions in the nation with some groups accusing OceanaGold of environmental and humanitarian crimes.
OceanaGold's shares closed at A$2.51 yesterday, valuing it at $1.74 billion. The stock has traded between $1.71 and $2.84 over the past year.
