MGX Resources (ASX:MGX) reported the completion of blasting of the central and ventilation portals for the Groundrush Exploration Decline operation at the Central Tanami project joint venture (CTPJV) in the Northern Territory, according to a Wednesday filing with the Australian bourse.

The company and Tanami Gold (ASX:TAM) each hold a 50% stake in the CTPJV, which aims to advance the project to a development decision in 2027, per the filing.

MGX said the construction of the portals is part of the initial works under a AU$38 million contract with Macmahon Holdings (ASX:MAH) unit Macmahon Underground.

The contract encompasses portal and vent establishment and the initial 3.5 kilometers of decline development to a depth of around 350 meters over 14 months. The decline will provide underground access for 33,000 meters of infill resource-definition drilling within the Groundrush gold deposit.

Macmahon Holdings shares fell 3% in early Wednesday trade.