Legend Mining Ltd (ASX:LEG) has hit the right rocks and host stratigraphy at the Octagonal prospect within the Rockford Project in WA’s Fraser Range that are “marker characteristics for a Nova style nickel-copper orebody”, according to executive chair Mark Wilson.
Diamond drilling is ongoing and the company is highly encouraged by hole OCDD004 in Target Area C, which intersected fertile host intrusion with zones of nickel-copper sulphide increasing with depth towards the basal contact.
Downhole EM (DHTEM) is now being carried out on this hole.
“Most informative drill hole”
Wilson said: “Diamond hole 4 has intersected the right mineralised intrusive rocks and favourable host stratigraphy, both being marker characteristics for a Nova style nickel-copper orebody.
"Importantly, in this hole, there is an excellent correlation between the seismic data and geology, and our technical team believe this hole will transpire to be the most informative drill hole at Octagonal to date.
"It has certainly given us confidence that the seismic/AMT target in hole 5 could be the accumulation of nickel-copper sulphide we are seeking.”
OCDD004 a success
Hole OCDD004 targeted the interpreted ‘keel zone’ of the Octagonal intrusion based on seismic interpretation. This zone is defined by a junction of structures interpreted to be the source pathway of the Octagonal intrusion.
The hole was extended to a bottom-of-hole depth of 1,710.8 metres to test a seismic zone below the known intrusion.
As a result, the interpreted zone is now confirmed as intrusion to 1,682 metres before intersecting metasediments, interpreted as the basal contact.
Section C-C’ showing holes OCDD002, OCDD004 and OCDD005 (ongoing) on seismic section and downhole geology and structure, the Octagonal intrusion and interpreted intrusion, and primary seismic and AMT targets.
In a highly encouraging prospectivity indicator for LEG, the fertile higher magnesium oxide intrusion was intersected at depth, with portable XRF confirming the presence of higher tenor nickel sulphide than previously encountered at Octagonal.
Structural information
In addition, valuable structural information has been gathered from logging of the metasedimentary country rocks, allowing the integration of physical structural data with seismic responses to map folding. The Octagonal Intrusive Complex (OIC) appears to have exploited the thick meta-conglomerate horizon, interpreted as a primary structural pathway for the OIC.
LEG believes this is a key development in the understanding of the emplacement of the OIC and subsequent targeting of nickel-copper accumulations as the known nickel-copper-cobalt deposits of the Fraser Range (Nova-Bollinger, Silver Knight and Mawson) are all proximal to meta-conglomerate horizons.
Hole OCDD005 underway
In Target Area B, diamond hole OCDD002 dropped more than the planned trajectory, which would have resulted in the drill hole missing the primary seismic and AMT targets.
The primary targets of Target Area B will now be tested with a new drill hole, OCDD005, which will test a seismic zone interpreted to be focused intrusion along strike from the bottom of OCDD004.
Drilling is underway and is expected to take 4-5 weeks with DHTEM to follow.