De Grey Mining Ltd (ASX:DEG) has revealed a strong pipeline of near to long-term exploration targets at the Pilbara Gold Project in WA following a systematic review of its extensive exploration database.
The targets range from immediate resource extensions of known large gold systems and walk-up drill targets at new prospects through to early-stage priority geochemical and or geological anomalies.
Seven new Toweranna analogues identified in a systematic review
Toweranna is an intrusion-hosted gold deposit, 250 metres in diameter, with stacked quartz vein lodes now extended beyond 200 metres depth.
The current resource of 2.01 million tonnes at 2.2 g/t for 143,900 ounces gold to 100 metres depth is planned to be updated in July.
New geological framework showing the seven walk up Toweranna drill targets and gold resource areas
The Toweranna deposit is the first intrusion-hosted gold deposit recognised in the Pilbara Craton and confirmation of its high grade, free milling characteristics and high gold recoveries has given it greater significance.
• All seven targets are significantly larger than Toweranna, ranging in strike length from 0.5 kilometre to 2 kilometres
• Five “walk up” drill targets defined with encouraging historical gold results including:
- Scooby - 3 metres at 2.67 g/t, 2 metres at 5.22 g/t, 6 metres at 1.03 g/t and 2 metres at 2.77 g/t.
- Shaggy - 12 metres at 1.25 g/t including 3 metres at 4.19 g/t, 13 metres at 0.98 g/t including 3 metres at 2.86 g/t
- Antwerp -16 metres at 0.74 g/t including 8 metres at 1.28 g/t, 8 metres at 0.84 g/t including 4 metres at 1.25 g/t
- Charity Well - 2 metres at 14.28 g/t, 4 metres at 2.24 g/t, 1 metre at 7.80 g/t
- Geemas - 5 metres at 1.20 g/t, 1 metre at 13.5 g/t, 1 metre at 7.02 g/t, 3 metres at 1.10 g/t
Five Toweranna targets located near Mt Berghaus
New resource extension targets defined at Withnell, Mallina and Mt Berghaus
At the 6-kilometre long Withnell Trend, with resources of 9.05 million tonnes at 1.8 g/t gold for 517,300 ounces, extensive remapping, relogging and 3D modelling by independent geological consultants, Model Earth, has defined numerous new potential resource extension targets.
At Mt Berghaus and Mallina, sub-audio magnetic surveys (SAM) show an extensive array of new targets immediately along strike from known gold lodes and elsewhere within the 6-kilometre and 5-kilometre respective trends.
SAM survey (6km x1km) at Mt Berghaus – strong correlation of SAM trends to known gold lodes
Below industry average discovery costs and high hit rate in RC and diamond drilling
• Low discovery costs less than $20 per resource ounce across the project historically
• Toweranna discovery costs shaping up to be significantly less
• 53% of diamond holes project-wide have intersected greater than 10 gram x metres (i.e. 5 metres at 2 g/t)
• 45% of RC holes project-wide have intersected greater than 5 gram x metres (i.e. 5 metres at 1 g/t)
Exploration focus 2019-2020
The recent exploration review has provided a leap in the geological, structural and geochemical understanding of the regional targets outside of the known resource areas, as well as within the Withnell Trend, Mallina and Mt Berghaus resource areas.
The recent drilling success at Toweranna where stacked lodes occur within an intrusive host and the mineralisation shows high gold recoveries and free-milling characteristics has provided a sharp focus and impetus to discover similar style mineralisation elsewhere in the project area.
READ: De Grey Mining test work reveals up to 96.3% gold recoveries at Toweranna
Until recently this style of mineralisation was poorly understood and not previously noted anywhere else in the Pilbara region.
This is an important recognition as this style of mineralisation in other Archaean goldfields of the world, including Kalgoorlie, have large scale multi-million-ounce deposits.
Seven Toweranna style targets have been recognised in the existing databases and ultrafine soil sampling, aircore programs commencing in the 2HY2019 and follow-up RC drilling programs will be planned subject to positive results over the coming 12 months.
Heritage clearance surveys will be required at some targets prior to drilling.
READ: De Grey Mining to work with Novo Resources on gold-bearing lag gravels
At Mt Berghaus and Mallina aircore programs are planned to test along strike targets defined in the new SAM surveys commencing in the 2HY2019.
Overall, De Grey is planning to undertake a series of significant aircore programs that are expected to be in excess of 70,000 metres across these high priority targets during 2HY2019 and 1HY2020.