Sulphate of potash (SOP) hopeful Trigg Mining (ASX: TMG) terms drilling results at its Lake Throssell project in Western Australia as “outstanding” after confirming what it calls a consistent and extensive high-grade system.
The average returned grade intercepted by the aircore drilling was 4,488 milligrams potassium per litre (mg/L), or 10.01 kilograms per cubic metre of SOP.
Trigg reports that drilling confirmed the presence of a broad palaeovalley, up to 5km wide and about 100m deep over a strike length of 36km.
“The basal palaeovalley sediments appear to have multiple aquifer targets at depth within the basal sediments, with sand and gravels logged for up to 35m in thickness in places,” it added.
Trigg managing director Keren Paterson says the results provide a strong foundation for the completion of a maiden mineral resource estimate early next quarter.
High-grade brine prevalent throughout system
“These are hugely encouraging results that confirm that Lake Throssell is a large-scale and remarkably consistent SOP project.
“It is very pleasing that the average grade of our assays has come in at the very upper end of our exploration target,” she added.
The maiden aircore drilling program at Lake Throssell began in late November 2020 and was completed in February 2021 (including a six-week suspension of drilling due to bad weather).
Trigg says the final brine results show that there is little variation in brine composition and grade at depth, with 96% of the brine samples falling within the 4,000mg/L to 4500mg/L potassium grade bracket.
“This indicates that high-grade brine is prevalent throughout the palaeovalley system and bedrock lithologies within the granted tenement under the lake,” the company noted.
Lake Throssell will help reduce dependence on imported potash
Some 253 brine samples were submitted for assay, returning high-grade results up to 5,800mg/L or 12.93kg SOP per cubic metre.
Ms Paterson said that the company was now looking to getting test trenches in place to begin the work aimed at gaining better understanding of Lake Throssell’s hydrogeological characteristics.
This work is an essential part of the feasibility studies.
Lake Throssell is one of several projects aimed at reducing Australia’s dependence on imported potash (both muriate of potash and SOP) now running at about 250,000 tonnes per annum.
The project is located 170km east of Laverton on the Great Central Road connecting Laverton to Alice Springs.