Legend Mining Ltd (ASX:LEG) had a “very busy” September 2021 quarter providing continued growth of the Mawson mineralised system at Rockford Project in WA's Fraser Range with the majority of holes drilled hitting nickel-copper sulphide in the right host rocks.
During the quarter, the company had two diamond rigs, DHTEM and the aircore rig in action, resulting in expenditure of $4.6 million.
On the regional front, Legend’s first diamond holes into Octagonal and Magnus have delivered confirmation that both of these prospects are prospective intrusive systems.
Legend now has three prospective locations - Mawson, Octagonal and Magnus - for the accumulation of the massive nickel-copper sulphides within the Rockford Project.
Mawson diamond drilling
Diamond drilling continued during September 2021 quarter, with 19 holes completed or ongoing for 9,319.7 metres.
Systematic step-out diamond drilling continues to grow the Mawson intrusion to the northeast, intersecting fertile intrusion as well as defining the architecture of the Mawson intrusion in relation to the country rock.
The 3D model driving predictive exploration at Mawson continues to evolve with new data and continues to be very accurate as a predictive tool for targeting interpreted fertile intrusion. The updated 3D constrained gravity model at this stage appears to have a high correlation for mineralised intrusion.
To date, the mineralised intrusive footprint at Mawson extends over 1.4 kilometres in strike length, with the gravity model suggesting the intrusion extends over 3 kilometres in strike length.
Legend’s first drill hole into the Octagonal Intrusion, OCDD001, is confirmation that Octagonal is a large, fertile, orthomagmatic nickel-copper intrusive system, akin to the known deposits of Nova-Bollinger and Silver Knight in the Albany-Fraser Belt.
Further work programs will interrogate the DHTEM from OCDD001 and target mineralisation across the Octagonal intrusion and at depth, with the aim to define an economic nickel-copper sulphide accumulation.
Magnus diamond drilling
The diamond drill hole MGDD001 intersected highly prospective mafic and ultramafic assemblages from 173.65 metres downhole to end of hole at 597.3 metres.
Minor variable disseminations of nickel-copper sulphides were identified over narrow zones throughout the drill hole.
Although not economic accumulations, the presence of nickel-copper sulphides confirms that Magnus contains prospective host rocks of an orthomagmatic system akin to Voisey’s bay, and indeed Nova-Bollinger, Silver Knight, Mawson and Octagonal.
Future work programs will include detailed structural analysis with focus on testing for economic accumulations of nickel-copper sulphide at depth and marginal locations around the intrusion.
Aircore drilling
A total of 149 aircore drill holes for 8,352 metres were completed during the September 2021 quarter.
Aircore drill testing will occur across three priority areas, primarily testing for fertile nickel-copper intrusions.
Regional aircore drilling will involve a program designed to test a number of aeromagnetic and gravity features interpreted to be mafic/ultramafic intrusives.
Follow-up of previous anomalous nickel-copper aircore results from the 2020 program will also be undertaken.
Results from these programmes will be reported once received.
Future programs
The future programs for the company include:
➢ Diamond drilling continuing systematically across at Mawson across priority target areas;
➢ DHTEM to be undertaken on all completed diamond drill holes;
➢ Integration of DD, RC, aircore geochemical and geophysical datasets to evolve 3D emplacement model of Mawson, with new constrained gravity and magnetic inversions and structural modelling ongoing;
➢ Diamond drilling and further aircore drill testing of Hurley, Crean, Magnus, and Octagonal;
➢ Regional aircore drilling of priority targets; and
➢ Regional innovative MLTEM and follow-up FLTEM.