Legend Mining Limited (ASX:LEG) has confirmed further diamond drill targets for nickel-copper sulphide mineralisation at its Rockford Project in WA's Fraser Range through a combination of innovative moving and fixed loop electromagnetic (MLTEM & FLTEM).
The surveys were over seven prospect areas - Northeast Mawson, Mawson Central, Worsley, Crean, Hurley, Magnus and Octagonal.
Legend also has the Worsley conductor W1 diamond drill-ready while Crean and a new prospect, Hurley, require final aircore drilling and infill surveys.
Legend managing director Mark Wilson said this work began late last year and was part of a regional exploration program at the Rockford Project.
He said: “The completion of the infill work at Crean and Hurley is expected to be in 4-6 weeks.
“Once this is finalised, we can plan a Rockford south drill program comprising Worsley, Shackleton and probably Crean and Hurley, dependent upon infill EM and aircore results.
“We are planning to extend the current Mawson diamond drill program to include conductors D13 and D15 once commitments in the main Mawson prospect are completed.”
Fixed loop electromagnetic (FLTEM) surveys over Northeast Mawson confirmed diamond drill targets at conductors D13 and D15, which are considered high-priority features based on their geological setting and conductance levels.
At Mawson Central, a low-frequency FLTEM survey was conducted over recently discovered nickel-copper sulphide mineralisation with the aim of overcoming the problem of highly conductive transported cover and the proximity of large graphitic/stratigraphic conductors to detect the sulphide mineralisation.
The technique was able to suppress the effects of the conductive transported cover and the western D5 conductor, but not the large D1 conductor to the south so the sulphide mineralisation was not detected.
While the company still considers this a valid exploration technique, further test work will be completed over the D1 conductor testing an offhole DHTEM feature adjacent to the previous diamond drill hole RKDD006.
Rockford Project showing prospect locations.
Worsley and Crean conductors
At Worsley, infill MLTEM surveying further refined the original MLTEM modelling revealing a broad/deep conductor of moderate conductance which corresponds closely with anomalous zinc-copper-silver results in previous aircore drill holes associated with metasedimentary host rocks.
A 400-metre diamond drill hole has now been designed to test this conductor.
Ten lines of MLTEM were completed at Crean following up anomalous nickel-copper-cobalt results in olivine-bearing ultramafic from previous aircore drilling (11 metres at 0.42% nickel, 0.01% copper, 0.03% cobalt from 32 metres to end of hole).
The survey identified the C1 conductor with follow-up aircore drilling planned to define the extent of the anomalous geochemistry is required along with a FLTEM survey to allow more accurate modelling of the conductor.
An initial four-line MLTEM survey at Hurley identified the H1 conductor further infill MLTEM required to allow accurate parameter modelling.
A second, less well-defined feature (H2) was also identified to the north and requires further surveying to better define the target.
Several lines of aircore will also be required to test for anomalous geochemistry prior to possible RC/diamond drill testing.