Legend Mining Ltd (ASX:LEG) has made strong exploration progress, identifying a new pipeline of prospective nickel-copper targets during the 2022 field season at Rockford Project in Western Australia's Fraser Range.
The company’s exploration activity continues across the Rockford Project with diamond drilling testing seismic targets at the lead Mawson Prospect, while regionally innovative electromagnetic and aircore drilling continues to identify nickel-copper targets.
To date, Legend has completed two diamond drill holes at Mawson, with the third in progress and a fourth in planning.
In addition, the company has also completed 65 aircore holes totalling 5,676 metres over an area to the southwest of the Mawson prospect, part of an extensive 30,000-metre regional aircore program across the entire Rockford Project.
A moving loop electromagnetic (MLTEM) survey has also been completed over the northern Rockford project area.
Busy in Rockford area
Legend managing director Mark Wilson said: “We have been very busy since the commencement of the 2022 field season with diamond drilling at Mawson and regional aircore and MLTEM programs elsewhere in the Rockford Project area.
“The first two diamond holes have intersected packages of rocks which are consistent with the geological interpretation of the seismic data. The third hole is currently being drilled beneath the Mawson fault in the vicinity of the discovery zone.
“Thorough interpretation of the seismic data based on these three holes will only be possible once all follow up information (DHTEM, geochemistry from assays, petrophysics, etc.) is received and processed.
“Meanwhile, the regional aircore drilling and innovative MLTEM surveys continue to identify a pipeline of prospective nickel-copper targets.”
Diamond drilling progress
RKDD081 was the first diamond drill hole to interrogate the interpreted keel below the Mawson fault and this largely intersected intrusive suites and metasedimentary packages where predicted.
RKDD082 and RKDD082W1 diamond drill holes were designed to interrogate an area of seismic signature interpreted to be a continuation of prospective chonolith below existing drilling, separated by a metasedimentary raft.
RKDD082 drill trace swung significantly off target, while RKDD082W1 intersected a largely prospective intrusive package below existing drilling levels, confirming the Mawson chonolith extends at depth as predicted.
The third diamond drill hole underway, RKDD083, is designed to intersect a seismic signature replication of that identified at the Mawson massive nickel-copper sulphide discovery zone, offset by the Mawson fault.
Heavy disseminated sulphide intrusion from RKDD081 from 840 metres, NQ2.
Aircore drilling
Legend’s aircore drilling was targeting a combination of aeromagnetic and gravity features interpreted to represent ultramafic and mafic intrusives within the same structural domain as Mawson.
The broad-spaced drilling has intersected prospective olivine bearing ultramafics and/or gabbronorite-norite mafic intrusions on all six traverses.
Infill aircore and high-power moving loop electromagnetic surveying are planned to further evaluate the potential of the region.
Drill samples from this program have been submitted for full analysis with all assay results pending.
Aircore drilling over gravity image and gravity inversion shells.
MLTEM surveying
Following a review of regional aeromagnetic and gravity datasets, previous aircore drilling and lithological domain mapping, 12 areas have been selected for follow up with innovative high power electromagnetic surveying.
This technique has proven successful in detecting conductive bodies beneath the thick, conductive transported cover for Legend across the Rockford Project
MLTEM surveying has been completed over the first area in the north identifying two large conductors.
The characteristics of these conductors suggest stratigraphic sources, however the presence of high MgO ultramafics in three drill holes (RKAC1420, 1453, 1456) in the vicinity of the north-western conductor warrants further evaluation.
Furthermore, drill hole RKAC1022 over the south-eastern conductor returned weakly anomalous results also requiring follow up work.
EM target areas over aeromagnetic image and gravity inversion highs.
Forward plan
Legend has outlined the future Mawson and regional Rockford programs as follows:
- Seismic interrogation ongoing;
- Diamond drilling of seismic targets at Mawson ongoing;
- DHTEM on completed diamond drill holes;
- Regional aircore drilling across highly ranked regional targets ongoing; and
- Innovative MLTEM across highly ranked regional targets ongoing
Rockford Project prospect locations on Gravity.