Great Boulder Resources Ltd (ASX:GBR) will start a new drilling program within a month to test higher-grade nickel targets at depth at Eastern Mafic nickel-copper-cobalt deposit within the Yamarna project in WA.
A revised geological model based on geophysics and drilling completed in the December quarter infers that the Eastern Mafic intrusion was formed at depth and the deep drilling will test this theory.
The company believes that drilling to date, which has returned encouraging copper, nickel and cobalt results, has only intersected the top of the intrusion, leaving the main body untested.
Evidence indicates that nickel grades increase at depth and the upcoming diamond drilling will take place under the conductors at Zermatt, ML13 and Ben Lomond.
READ: Great Boulder Resources gains further evidence of Eastern Mafic potential, adds PGEs to the mix
Elevated platinum group elements (PGE) have also been intersected at Ben Lomond and ML13 which have potential to provide by-product credits.
Great Boulder’s Yamarna project and Winchester and Mt Carlon projects, which are under option agreements.
Up to four diamond holes are planned in the program, which is co-funded by the Western Australian Government.
Great Boulder is funded for the planned exploration and at December 31, 2018, had $1.8 million in cash after receiving an R&D rebate of $827,000 in December.
Assisted by WA EIS scheme
A WA Government Exploration Incentive Scheme (EIS) grant of $150,000 has been approved and will be received by the end of this quarter after the deep drilling is completed.
The project exhibits an increase in nickel tenor which makes it an attractive target to provide potential higher-grade blend for Yamarna’s Mt Venn and Eastern Mafic deposits.
Further activities at Winchester will begin once the tenement’s extension of term is granted and a formal joint venture with Ausgold is executed.
Winchester drill hole plan showing interpreted geology and significant intercepts.
At the advanced Mt Venn project west of Eastern Mafic metallurgical test work is generating high purity copper, nickel and cobalt products.
Several optimisation steps were undertaken in the December quarter, focused on simplifying the nickel and cobalt flowsheet to produce a high-grade combined nickel-cobalt sulphide product rather than separate nickel sulphide and cobalt sulphate products.
This would remove the capital and operating costs associated with a solvent extraction plant for the sulphate production and improve overall handling and freight costs associated with two simple sulphide products.
New test work results expected
Results from the updated metallurgical test work are expected in February.
Once a final product mix is selected, further metallurgical samples will be collected from the Eastern Mafic, Mt Venn and Winchester to generate a representative sample for optimisation test work.
Drilling at Mt Venn continues to intersect wide zones of copper dominant mineralisation.
These have now been defined over 1 kilometre of strike and remain open along strike and downdip.
Great Boulder is now assessing further strike extensions along the Mt Venn mineralised trend to the north and south where limited previous drilling has been undertaken.
Once the full extent of mineralisation is mapped the company will begin resource definition drilling.