The Dalgaranga mine site has produced significant recent production of tantalum with encouraging lithium results from surface sampling at the pit and its surroundings.
Lithium minerals already identified were not the focus of historical exploration & mining activities.
Krakatoa is committed to a comprehensive exploration & development plan to evaluate defined prospect areas.
Results from Dalgaranga's maiden reverse circulation drill program were announced in October 2017, and uncovered extensive Rubidium mineralised Pegmatites.
The drill hole program completed 11 vertical RC drill holes at 1,066 metres
Assays reveal evidence of wide zones (up to 71m) of Rubidium enrichment and confirm the existence of Tin, Tantalum and Niobium
Fifty-six percent of the samples returned Rb values exceeding 1000ppm, with a peak value of 4943.3ppm (0.49%)
Associated Berylium, Cesium, Niobium, Lithium, Tin and Tantalum is characteristic and supports the presence of a Lithium-Cesium-Tantalum (LCT) Pegmatite at Dalgaranga
The complete ASX announcement can be viewed here.
The geology of the Dalgaranga Project consists of a suite of fine grained, foliated, clastic sediments (siltstone and arkose) with tuffaceous units occurring on the eastern margin.
Tuffaceous units within the open pit include bands (<300mm) of chiastolite rich siltstone (“knotted schists”). The rocks are folded with north easterly axes and are often moderately foliated. Banded iron formations exist on the north west margin.
The “Open Pit Pegmatite Vein” and those veins to the south appear to have been intruded parallel to the folded sediments. Within the open pit area pegmatites range between 0.5 to >10m in thickness. To the south of the ROM and tailings dam, pegmatites ranging between 0.5 to 3m thickness have been mapped.
The main tantalum minerals at Dalgaranga Mine were tapiolite and tantalite, with lesser microlite. Tantalite ranged from very fine grained to very coarse, up to several centimeters. Local concentrations of tin, tungsten and lithium minerals have also been noted.
Occurrences of Zinnwaldite (lithium mineral, KFe22+Al(Al2Si2O10)(OH)2 to KLi2Al(Si4O10)(F,OH)2) have been noted by the Western Australian Museum. Detailed mapping and sampling is to be undertaken to determine the potential and extent of lithium mineralisation within the Project.
Rock Chip Sampling
A rock chip sampling campaign was conducted within the vicinity of the historical Dalgaranga Open Pit. The program aimed to determine the tenor of exposed mineralisation within the open pit, confirm the presence of Zinnwaldite (lithium mica mineral) and develop an understanding of the potential for hosting extensions to the previously mined tantalum-niobium mineralisation.
Rock chip samples returned up to 1,854ppm Ta2O5 confirming that high grade mineralisation remains within the open pit. Detailed mapping and channel sampling is proposed to be conducted to determine the extents of mineralisation within the surrounds of the open pit.