Junior explorer Trigg Mining (ASX: TMG) has announced a maiden indicated mineral resource estimate for its high-grade Lake Throssell potash project in Western Australia’s northern goldfields region.
A drainable resource of 1.9 million tonnes sulphate of potash (SOP) at 4,985 milligrams per litre potassium (or 11.1 kilograms per cubic metre potassium sulphate) has been estimated based on results of recent trench pump trials of the project’s surficial aquifer resource.
The trials demonstrated the geological continuity of brine grade and extraction from the aquifer, converting over 95% of the mineralised blocks from the top 6m of the aquifer resource model to indicated status.
The maiden indicated resource equates to 13% of the project’s total mineral resource of 14.3Mt drainable SOP at 4,665mg/L potassium (or 10.4kg/m3 potassium sulphate).
New exploration target
Trigg has also updated its exploration target at Lake Throssell, indicating “strong potential” to expand the resource estimate.
The new target (in addition to the maiden resource estimate) ranges between 2.6Mt and 9.4Mt at up to 10.0kg/m3 potassium sulphate.
It is based on the results of exploration activities to date, which have encompassed a strike length of approximately 36km of the project’s interpreted palaeovalley system.
An additional 34km of strike length has been extrapolated into four other tenement applications considered to host similar geology and brine characteristics.
The maiden resource estimate follows the release of an “outstanding” maiden inferred resource for the Lake Throssell project just over two months ago.
SOP production hub
Trigg managing director Keren Paterson said today’s announcement marks another key milestone in the company’s aim of developing a long-life sulphate of potash production hub in the Laverton district.
“We have moved rapidly to estimate a high-quality indicated resource which will provide the basis for the initial payback period to underpin [the Lake Throssell] scoping study,” she said.
“We expect to convert additional tonnes to indicated status next year as we progress work on the deeper portions of the resource and further expand our overall inventory with further drilling.”
Situated 170km northeast of Laverton, Lake Throssell comprises a total of 1,084 square kilometres in granted and pending exploration tenure.
The extensive palaeovalley system has been identified through 200-line kilometres of gravity surveying and the maiden resource estimate has been based on 80 aircore and rotary drill holes for a total 5,720m.
The brine pumping trial completed at Lake Throssell – from two 100m-long trenches over 10 days and across seven test pits – improved the confidence of the project’s lake surface surficial aquifer to indicated status.
Ms Paterson said completion of a scoping study and installation of test production bores to improve the resource confidence level of the basal aquifer units “remains a high priority”.