Drilling at Trigg Mining’s (ASX: TMG) Lake Throssell sulphate of potash project in WA has confirmed a palaeovalley system saturated in hypersaline brine.
A maiden aircore drilling program began at the project in November, which was designed to test the basal aquifer from the 46km anomaly that was identified from ground gravity surveys.
Drilling has confirmed the palaeovalley is at least 1km wide, but could be up to 4km wide in places.
Ausdrill carried out the program using a track-mounted aircore rig and has completed 16 holes for 1,806m. Drilling reached a maximum depth of 130m and follows previous shallow exploration of the surficial aquifer.
According to Trigg, visual inspection of aircore samples suggests the palaeovalley comprises multiple aquifer zones with a thick upper sequence of lacustrine clays with gravel and rock fragments occurring to the base of the sequence.
Preliminary field analysis of salinity in the palaeovalley has been comparable to that encountered in the surficial aquifer.
Previous hand and rotary drilling of this surficial aquifer returned brine grading up to 14,800 milligrams per litre of SOP.
By August this year, Trigg had completed 26 holes of shallow rotary drilling across the playa area of the lake to 10m depths and targeting the surface aquifer.
The average grade of 77 brine samples collected came in at 11,300mg/L, with 90% of the holes exceeding 10,000mg/L.
Similar to the rotary drilling, Trigg managing director Keren Paterson said the company was “very encouraged” by the early results from the aircore program.
She added the results build on the high-grade hits in the surficial aquifer and underpin the company’s theory Lake Throssell could be a “significant” new SOP project.
Progressing Lake Throssell
Located 170km east of Laverton in Western Australia, Lake Throssell is believed highly prospective for SOP.
Brine samples from this latest drilling at the project have been submitted for analysis with results anticipated in the New Year.
Once all drilling has been completed and assays are at hand, Trigg expects to publish a maiden resource for the target.
Drilling has been temporarily suspended due to a rain event, with the company anticipating it will resume as soon as conditions permit.