Legend Mining Ltd (ASX:LEG) is gearing up to conduct a downhole transient electromagnetic (DHTEM) survey on recently completed diamond drill hole OCDD005 after the hole intersected a “mixing zone” with magnetite and pyrrhotite at the Octagonal prospect within the Rockford Project of Western Australia.
Positioned at the source of an Audio-frequency Magnetotellurics (AMT) feature, the hole did not intersect nickel-copper mineralisation but offers an opportunity to survey the target at depth.
High-powered EM survey
“The AMT feature which hole 5 was designed to test turned out to be largely magnetite and pyrrhotite, which explains the lack of significant nickel-copper sulphide in this hole,” Legend Mining executive chair Mark Wilson said.
“Whilst we need to await the DHTEM results and structural analysis to appreciate the totality of information from this hole in particular, the results from the recent 4-hole program have not reduced the overall prospectivity of Octagonal.
“These drill holes represent the first steps in unlocking the nickel-copper sulphide potential at Octagonal.
“From the information to date, it is becoming increasingly apparent that the best mineralisation is on the eastern flank of the prospect. This is further evidenced by the 4 conductors from DHTEM in hole 4.
“A decision has been made to conduct a large high-powered electromagnetic (EM) survey over Octagonal with the design capacity to identify conductive responses below a depth of 600 metres.
“This is expected to deliver EM data which along with the seismic and other data sets will give us the next generation of diamond drill targets.”
LEG intends to conduct a High-Power Fixed Loop Electro-Magnetics (HPFLTEM) survey over the entire Octagonal intrusion with the goal of identifying large sulphide bodies at depth.
The company will then plan a diamond drilling program based on the HPFLTEM survey’s results.