The Discovery Deeps 2 mine has been officially opened at the Sepon gold-copper operation in Lao PDR, marking the completion of a major underground mine development that extends the life and production capacity of one of Southeast Asia’s significant mining operations.
The opening ceremony was attended by Lao PDR government officials and company representatives, reflecting the strategic importance of the expansion for both the mining operation and the host country. The Discovery Deeps 2 mine represents the next phase of underground mining at Sepon, building on the foundations established by earlier underground developments at the site.
Underground Expansion and Mine Development
The Discovery Deeps 2 mine was developed to access deeper gold mineralisation beneath the existing Discovery open pit and the earlier Discovery Deeps underground workings. The project involved the construction of a new decline and associated underground infrastructure to reach ore zones that could not be economically accessed from the surface.
Development of the Discovery Deeps 2 mine included the excavation of approximately 5.5 kilometres of underground development, encompassing the main decline, ventilation infrastructure, and ore drives. The project was delivered on schedule and within budget, according to the company. The mine is designed to produce gold ore that will be processed through the existing Sepon processing facility, allowing the operation to maintain production without the need for additional surface infrastructure.
The underground mining method employed at the Discovery Deeps 2 mine is long-hole open stoping with paste backfill. This method was selected based on the geometry and grade distribution of the ore body, and it allows for efficient extraction while maintaining ground stability at depth. The paste backfill system uses tailings from the processing plant, reducing surface storage requirements and supporting the operation’s environmental management approach.
Production Capacity and Operational Integration
The Discovery Deeps 2 mine is expected to contribute a meaningful proportion of ore feed to the Sepon processing plant over the coming years. The underground operation complements ongoing open pit mining activities at Sepon, which continue to provide ore from several satellite deposits across the broader mining lease.
Gold production from the Sepon operation has historically been sourced from both open pit and underground mining. The addition of the Discovery Deeps 2 mine to the production profile provides the operation with greater flexibility in ore sourcing and blending, which supports consistent feed grades to the processing plant. The mine is expected to operate for several years, contributing to the extension of Sepon’s overall mine life.
Workforce development has been a notable aspect of the Discovery Deeps 2 mine project. The company reported that a significant proportion of the underground workforce comprises Lao nationals who have been trained in underground mining techniques. This investment in local capability supports the operation’s commitments to the Lao PDR government regarding employment and skills transfer.
Infrastructure and Engineering Delivery
The engineering and construction programme for the Discovery Deeps 2 mine involved detailed geotechnical assessment, hydrogeological management, and ventilation design to ensure safe and productive operations at depth. Ground support systems were installed throughout the decline and ore drives to manage the geotechnical conditions encountered during development.
Water management underground was addressed through a pumping system designed to handle inflows encountered during development and production. Ventilation infrastructure, including raise-bored ventilation shafts, was established to provide fresh air to the working areas and maintain compliance with occupational health standards.
The successful delivery of the Discovery Deeps 2 mine positions the Sepon operation to sustain gold production as open pit sources are progressively depleted. The company indicated that further underground opportunities within the Sepon mining lease are being evaluated, with exploration and resource definition work continuing across the broader tenement package.
Production from the Discovery Deeps 2 mine has already commenced, with first ore delivered to the processing plant ahead of the official opening ceremony.