Sandfire Resources announces Old Highway maiden MRE

Highlights

• Maiden mineral resource estimate completed for the Old Highway gold deposit, located approximately 20 km WSW of Sandfire’s DeGrussa Copper-Gold Mine in Western Australia:
  • Indicated mineral resource of 2.8 million t at 2.5 g/t gold (Au) for 223 000 oz of contained gold.
• Studies underway to evaluate potential development options including producing gold through modification of the existing DeGrussa processing infrastructure – on-track for delivery in the March 2022 Quarter.
• Drilling is continuing at Old Highway with a ~9100 m (24-hole) diamond drill programme underway focused on extending the high-grade mineralisation in the ‘Central Deeps’ section of the Old Highway deposit.
  • Eight holes (~3200 m) completed to date, the majority of which have intersected quartz veins in the expected position down-dip from the known mineralisation – assays awaited.
  • The deepest holes will test ~200 m below known mineralisation.

The indicated mineral resource comprises 2.8 million y grading 2.5 g/t Au for 223 000 oz of contained Au.

Study work is currently underway to assess the potential development options for the Old Highway gold deposit. As part of the study Sandfire has completed preliminary design and costing for the addition of a gold recovery circuit to the existing DeGrussa copper concentrator. Study work is continuing and is expected to be completed in the March quarter of 2022.

Drilling is continuing at Old Highway with a ~9100 m (24-hole) diamond drill programme commenced, focused on extending the high-grade mineralisation in the central section of the Old Highway deposit – an area known as ‘Central Deeps’ – which remains open along strike and down dip. The deepest holes from this programme will test ~200 m below the currently defined extent of the mineralisation.

Eight holes (~3200 m) of this programme have been completed to date, the majority of which have intersected quartz veins in the expected position down-dip of the known mineralisation. Assay results for these holes are awaited.

Project development studies

Sandfire has completed a number of study elements to support the completion of the MRE and assess potential development options for the Old Highway deposit, including:

• Preliminary opencast and underground design work in progress, including geotechnical and hydrology studies.
• Metallurgical testwork including variability work on the different ore lithologies has been completed. The ore is free milling with overall very high gold recoveries exceeding 90% at moderate grind size of 106 microns and low reagent consumptions.
• Preliminary design and costing for the addition of a gold recovery plant to the existing DeGrussa copper concentrator. This would involve the addition of gravity, CIL and gold recovery circuits. The existing concentrator crushing and grinding circuits could be re-used with only minor modification required.
• All baseline environmental work at Old Highway has been completed and documentation for the various approvals is in progress.
• Ore haulage options for the transport of ore from Old Highway to DeGrussa have been investigated and preliminary costs for the options established.
• Various CIL tailings storage options including use of the existing DeGrussa TSF and in-pit deposition into the DeGrussa pit have been investigated.

Mining leases M52/1080 and M52/1081 have been granted for the Old Highway project area.

Sandfire Managing Director and CEO, Karl Simich, said: “With the scheduled completion of copper-gold production from DeGrussa in the September Quarter of next year, this maiden Mineral Resource for the Old Highway deposit provides a solid start for a potential future gold operation leveraging the existing processing infrastructure on site.”

“Given that the infrastructure is already there, even a relatively small-scale gold Resource has the potential to deliver solid financial returns.

“Sandfire already has an exceptionally strong asset pipeline, with our acquisition of the world-class MATSA Mining Complex in Spain nearing completion and the development of our new Motheo Copper-Silver Mine in Botswana well underway.

“We will continue to progress feasibility studies for Old Highway in parallel with delivering these other global growth initiatives.”

Read the article online at: https://www.globalminingreview.com/exploration-development/30122021/sandfire-resources-announces-old-highway-maiden-mre/