ERO Mining on the search for lithium
THE DRILL SERGEANT: ERO Mining has commenced an initial sonic drilling program at its Wertaloona lithium project adjacent to the Frome saltpan in central-northern South Australia.
The commencement of the program comes after the company received Aboriginal Heritage clearance with the Adnyamathanha people,
The Wertaloona project is part of two exploration licences ERO procured via its acquisition of unlisted mineral explorer, South East Energy, which is now a 100%-owned subsidiary of ERO.
Regionally the project area consists of 1,757 square kilometres that lie largely inside the Lake Frome Conservation Park, within which exploration and mining are allowed, with the remainder sitting in pastoral lease land.
According to ERO the area is underlain by several hundred metres of sediments containing sandstone beds with potential to host lithium-bearing brines.
Sonic drilling is a technique that uses vibration frequencies allowing ease of penetration, which is able to return near complete and relatively undisturbed core samples from solid and unconsolidated materials.
A hydraulic mechanism removes any need for drilling fluid minimising the chance of contamination of core samples.
Dual tube drilling methods allow for simultaneous sampling of formation waters while drilling.
The drilling program is to comprise two fully cored drillholes totalling approximately 300 metres and down hole gamma surveys.
The drillholes are to be close to two holes previously drilled by Comalco in the 1970s, when significant lithium levels were encountered.
This previous exploration work at Lake Frome undertook very broad scale testing of the surface and subsurface brines for trona (a source of sodium carbonate) and other associated salts for industrial purposes.
More significantly, it also encountered significant lithium concentration in the southwestern corner of Lake Frome and the adjacent lowlands.
ERO notes that the Comalco investigations were only carried out in the upper part of the Namba Formation and overlying younger sediments and that the drilling was extremely broad scale. Underlying sediments remain untested for lithium.
By undertaking the current program ERO hopes to greatly expand the depth of the historic drilling undertaken by Comalco and to test all of the middle Tertiary Namba Formation and underlying early Tertiary Eyre Formation.
Drilling technologies used by Comalco in the 1970s meant it was unable to fully test the Namba Formation or penetrate to the Eyre Formation.
ERO has carried it its own evaluation of the untested parts of the sedimentary succession and is confident of their potential to host lithium and uranium.
The company will also be taking brine samples hosted in all sandstone layers and systematically spaced sediment samples looking for lithium and other indicators, including uranium, while carrying out further hydro-geological test work employing modern techniques.
The potential of expanded drilling programs with greater focus on economic lithium concentrations, brine flow rates and volumes will also be assessed.
ERO is of the opinion the fully cored holes will provide a much better understanding of the lithium-bearing sediments and brines and will eventually become important reference holes for future drilling.