The Broken Hill Project (Impact Earning 100%)
The Broken Hill Ni-Cu-PGE Project is located 20 km east of the World Class Broken Hill silver-lead-zinc mine in New South Wales, and consists of one Exploration Licence (EL7390) covering 200 sq km in the south east part of the richly mineralised Curnamona Province (Figures 1 and 2).
Impact owns 100% of three of the licences. The mineral rights for the fourth licence, EL7390, were split in the early 2000’s into the two different styles of mineralisation. Impact recently acquired EL7390 from Golden Cross Resources Limited and this entitles Impact to:
- 100% of the PGE-copper-nickel mineralisation; and
- 80% of the zinc-lead-silver Broken Hill-style mineralisation in EL7390 in joint venture with Silver City Minerals Limited (ASX:SCI). Impact will free-carry Silver City’s 20% interest to a Decision to Mine.
Golden Cross has a 1% gross production royalty on all metals to which Impact has rights for. Impact, at its election, also has the right to buy back the royalty for $1.5 million at any time up to a Decision to Mine, or leave the royalty uncapped during any production.
The project area contains many tens of strike kilometres of mafic-ultramafic sills, dykes and stocks that contain gossans and fresh outcrops with very high-grade PGE’s, nickel, copper, gold and silver mineralisation (Figure 2).
The on-going review and synthesis of previous exploration results at the Broken Hill Project has highlighted:
- that around 500 tonnes of ore was mined from the dormant Red Hill Mine between 1906 and 1937, with face samples returning a grade range of:
2 to 4% copper, 2 to 3% nickel, 5 to 41 g/t PGE and 22 to 70 g/t silver;
- rock chip assays over a 130 m by 30 m area trending northeast from the Red Hill Mine, close to the contact between the host ultramafic intrusion and the surrounding rocks returned a grade range of:
1 to 36 g/t PGE and 0.2 to 6.1% copper; and
- previous exploration drilling has not tested the mineralised areas.
- Significant potential for the discovery of bulk tonnage PGE mineralisation together with very high-grade nickel-copper-precious metal massive sulphides throughout the Project area.
- A joint venture with Golden Cross Resources, Impact can earn 80% by spending a further $550,000 by 2017.
- Widespread high grade copper, nickel and platinum group mineralisation confirmed at the Red Hill Prospect.Tens of kilometres of strike of the ultramafic intrusions yet to be tested.
- High-grade massive nickel-copper sulphides and precious metals have been found at the Mulga Springs Prospect and include 4 m at 17.9 g/t Pt+Pd+Au, 2.3% nickel and 3.2% copper from 43 m in hole GMS-006.
- Outcrops of some of the highest-grade PGE gossans in Australia occur in many places along the Mulga Springs Gabbro and include the very rare PGE metals osmium, iridium and ruthenium.
Previous exploration has focused along the basal contact of the Mulga Springs Gabbro, a series of shallow northeast dipping mafic-ultramafic sills extensively developed over 10 km of strike from the Mulga Springs Prospect in the south to Moorakie in the north (Figure 3). Previous exploration at Mulga Springs has:
- identified a representative 120 kg sample of gossan which returned 19.6 g/t platinum, 50 g/t palladium, 3 g/t rhodium, 3 g/t osmium, 4.4 g/t iridium, 2 g/t ruthenium, 0.57 g/t gold, 0.34% nickel and 0.71% copper;
- identified drill intercepts (Figure 4) in fresh sulphide at about 45 m depth of:
GMS-006: 4 m at 17.9 g/t Pt+Pd+Au, 2.3% nickel and 3.2% copper from 43 m; and
DD4: 2.1 m at 8.3 g/t Pt+Pd+Au, 3% nickel and 3.5% copper from 45 m;
- demonstrated potential for the discovery of large deposits of very high grade nickel-copper-PGE massive sulphides and bulk tonnage PGE mineralisation among many tens of strike kilometres of mafic-ultramafic sills, dykes and stocks similar to those at Norilsk in Russia and Jinchuan in China.
Work by Endeavour has shown that the main body of the gabbro also contains extensive PGE mineralisation (Figure 5) with better intercepts of:
GMS-017: 14 m at 0.82 g/t Pt+Pd+Au and GMS-013: 12 m at 0.46 g/t Pt+Pd+Au.
The Red Hill Mine
The Red Hill Mine occurs in ultramafic rocks that cross cut deformed and metamorphosed rocks of the Broken Hill Group. The ultramafic rocks outcrop over an area of 500 m by 250 m and mineralisation occurs close to the western contact.
Red Hill was mined for copper between 1906 and 1937 both at surface and underground, from a vertical shaft to a depth of 36 m. Old mine records sourced by Impact indicate that about 500 tonnes of ore was mined from four parallel ‘lodes’, each 1 m to 2.5 m wide. Face samples from the underground mine returned a grade range of 2 to 4% copper, 2 to 3% nickel, 5 to 41 g/t PGE and 22 to 70 g/t silver. The lodes are open along strike and at depth (Figure 6).
About 70 rock chip samples taken over a 130 m by 30 m area trending northeast from the Red Hill Mine returned assays with a grade range of 1 to 36 g/t PGE and 0.2 to 6.1% copper near the western contact of the ultramafic rocks. These results have not been followed up.
Investors should note that these assays may have been upgraded by near surface weathering. However, at the Mulga Springs Prospect (Figure 1), drilling beneath samples with similar surface grades has identified massive sulphide mineralisation in fresh rock at about 45 m below surface with intercepts of:
4 m at 17.9 g/t Pt+Pd+Au, 2.3% nickel and 3.2% copper from 43 m; and
2.1 m at 8.3 g/t Pt+Pd+Au, 3% nickel and 3.5% copper from 45 metres.
Work at the Broken Hill Project is ongoing, with re-analysis and synthesis of previous exploration results expected to confirm the potential for bulk tonnage PGE mineralisation.
A field programme has commenced at the Red Hill prospect and comprises field checking and soil and rock chip sampling. Re-processing of a previous ground EM survey over the area is also underway.