Trigg Mining (ASX: TMG) has discovered a large scale palaeovalley beneath its Lake Throssell sulphate of potash project that has the potential to host “significant” potassium-rich brines.
This structure is defined as a remnant of an inactive river or stream channel that has been filled or buried by younger sediment.
Trigg’s gravity survey has confirmed the presence of the palaeovalley beneath Lake Throssell. It has been modelled to a depth of about 120m below surface.
The deep structure has an apparent northeast-southwest trend, is potentially up to 6km wide in places and extends for about 46km under the company’s granted tenement.
Rainfall over millions of years, carried through paleochannels below what is now desert, has accumulated beneath the surface with high potassium content and the area’s now high evaporation rate of about 3m a year has left large brine resources.
Trigg says the most prospective portion of the palaeovalley sequence (the thalweg, or deepest part of the ancient riverbed) is most likely to host sand-rich aquifers which in turn contain the potassium in brine.
“In places, the modelling suggests that this thalweg may be up to 2km wide,” the company noted.
The Lake Throssell SOP project covers about 694 square kilometres of granted and pending tenements, within which there are 190sq km of salt-lake playa and 70km of underlying interpreted palaeochannels.
Lake Throssell is located 170km east of Laverton in Western Australia – on the Great Central Road connecting Laverton to Alice Springs.
The WA and federal governments are sealing the road with work on the first 40km now underway. This will establish the Outback Highway connecting WA to the Northern Territory and Queensland.
Drilling next month, maiden resource in last quarter
These latest results will allow Trigg to refine its targeting of the most prospective parts of the palaeovalley.
This will be followed by the inaugural aircore drilling program planned to begin by mid-September, followed in turn by a maiden mineral resource to be released in the December quarter.
Trigg managing director Keren Peterson said the latest results indicate the strong potential to delineate a SOP deposit of significant scale.
“This is [a] very important development for our exploration program and significantly increases our confidence in the potential of the Lake Throssell project,” she added.
Drill locations are now being finalised.