Greatland Gold PLC (AIM:GGP, OTC:GRLGF) said development of the Havieron project is to be temporarily paused to assess how to manage the water extraction from an aquifer above the main orebody.
At more than 2,030 metres on 8 October 2023, some 770 metres of development remain before the decline reaches the top of the Havieron orebody, the junior said.
The decline is also approaching a lower confined aquifer (LCA), with approximately 280 metres of development remaining before it is intersected.
Water from two shallower aquifers has already been pumped to the surface and LCA is the final aquifer that the underground decline passes through before reaching the Havieron orebody.
Ahead of reaching the LCA, depressurisation drilling has commenced and groundwater is being pumped to the surface.
This has indicated the potential for greater volumes of water to be managed at the surface than originally modelled.
In order to increase the confidence in water management from the LCA, further hydrological drilling, data collection and evaluation will be undertaken, said Greatland
To allow this work to occur, development will continue to advance in the short term before a temporary pause in decline development prior to entering the LCA, commencing later this quarter.
Greatland added this work should ensure a more efficient entry into, and development through, the LCA and likely reduce subsequent water management operating costs.
Feasibility study works will continue, incorporating further hydrological drilling, data collection and enhanced understanding of the LCA and water management requirements.
Various other workstreams are moving forward as part of the feasibility study, which Greatland now expects to be completed by September 2024 as partner Newcrest wants the study to incorporate the understandings from development through the LCA.
Shaun Day, Greatland’s managing director, said: "Havieron is an outstanding orebody which has been developed on an expedited basis in parallel with the finalisation of the Feasibility Study.
“Through this approach, production can be brought forward to enhance the value of the asset
“At the same time, it is essential that we continue to set the project up for long-term success by optimising and de-risking the current development phase.”
Havieron is a 30/70 joint venture between Greatland and Newcrest/Newmont.