ASX-listed Trigg Mining has launched a gravity survey over its Lake Yeo sulphate of potash fertiliser, or “SOP” project in Western Australia. Via the survey, Trigg seeks to pinpoint drill targets and evaluate the project’s potential to represent a repeat of its nearby Lake Throssell SOP deposit where a 21 year mine life generating $97 million a year in EBITDA was recently estimated in a scoping study.
Trigg believes Lake Yeo could lie in the same palaeovalley that also hosts its Lake Throssell resource some 65 kilometres north-west. The maiden gravity survey will seek to better define the palaeovalley and potential storage capacity of the aquifer at Lake Yeo.
A paleovalley – also known as a paleoriver or paleochannel – is a geological terms to describe an inactive river or stream channel filled or buried by younger sediment.
Lake Throssell lies within a palaeovalley system at the project that stretches for about 36km in length, up to 5km width and 150 metres depth, according to the company.
Trigg has defined an impressive ‘drainable’ mineral resource at Lake Throssell taking in 14.4 million tonnes of SOP grading 4,655 milligrams per litre potassium, or 10.6 kilograms per cubic metre potassium sulphate.
According to Trigg, Lake Yeo could potentially host brine of similar grade and composition as Lake Throssell.
Trigg has also commenced a gravity survey at Lake Throssell to better define the basal aquifer ahead of its planned drilling of test-production bores next year. The works form a part of a recently launched pre-feasibility study and are designed to convert the existing mineral resource at the project into an ore reserve.
Results from both gravity surveys are anticipated for release early in the new year.
Trigg Mining Managing Director, Keren Paterson said:“The current in-fill gravity program at Lake Throssell signifies the formal start of the Pre-Feasibility Study and will assist with identifying potential resource extensions and help to refine the planning for the test-production bores expected to be drilled in the middle of 2022…
Lake Yeo lies just to the south, along the same interpreted palaeovalley and has similar signatures for potassium and sulphate as Lake Throssell. The maiden gravity survey is designed to identify the palaeovalley and potential future drill-hole locations to test this exciting Project. If we are successful with our upcoming exploration activities, this could be a transformational development that results in a dramatic expansion of our growth pipeline in the district, around a central SOP processing hub based at Lake Throssell.”
The pre-feasibility study evaluating the production of SOP at Lake Throssell comes on the back of a robust set of numbers which were set out in a recent scoping for the proposed venture.
The study projected about 245,000 tonnes of SOP production per annum over the initial 21-year mine life, with an average annual revenue of $180 million.
It also generated a pay-back period of just 4.5 years for an initial $378 million capital outlay. Average cash operating cost per tonne of SOP clocked in at about $341, with an all-in sustaining cost of $372 per tonne.
A net present value of $364 million with an internal rate of return of 18 per cent were also estimated in the scoping study.
Production at Lake Throssell is anticipated to involve harvesting of saline brine water from subterranean aquifers. In turn, solar evaporation of the brine will generate a naturally forming SOP for use as a fertiliser and other industrial purposes around the world.
Trigg has already defined a hefty resource and long-life SOP production profile at its Lake Throssell discovery. The Perth-based company could send a few hearts racing if it also replicates the deed at Lake Yeo.
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