Exploration and development company Kalium Lakes (ASX: KLL) has reported a significant increase in brine aquifer thickness from a drilling program at the Lake Sunshine target within its flagship Beyondie sulphate of potash (SOP) project, 160 kilometres south-east of Newman in WA.
A total of 23 holes for 2,066m were completed at the Jilyili sandstone formation below the geologically-ancient palaeovalley and weathered bedrock to test for brine grade and drainable porosity.
Drilling revealed an increase of 145% in brine aquifer thickness and up to 20,872 milligrams per litre SOP (9,360mg/L potassium) from more than 100m – making it the highest SOP grade recorded at Lake Sunshine to date.
Results showed the sandstone extends to a depth of 196m with interbedded friable and cemented sandstone bands and minor siltstone.
Brine samples were obtained at regular intervals throughout the profile with airlifts rates typically only restricted by the anulus of the drilling system.
Borehole magnetic resonance logs have been run in the open holes to measure drainable porosity.
Managing director Brett Hazelden said the results would allow Kalium’s current production bore installation program to take advantage of higher grades and increased thickness of brine as part of stage one of the $216 million Beyondie development.
He anticipated a significant mineral resource increase to be finalised in the new year.
The drilling program at Lake Sunshine comprised nine aircore and 14 deep reverse circulation hammer drill holes to test the bedrock sandstone for its aquifer potential and brine content.
Aircore drilling was able to penetrate the weathered zones of the sandstone sequence, but not the more cemented siliceous bands which are present.
Hammer drilling was used to drill to depth or at such point that drilling penetration rates slowed due to the volume of brine bring unable to be lifted with the compressor.
An auxiliary compressor was mobilised to drill five deeper holes at the end of the program.
All holes are reported to have encountered fine to coarse-grained sandstone with minor siltstone and shale bands of the Jiliyili formation, which outcrops extensively in the Lake Sunshine area.
Brine grades typically increased with depth at drill locations on the edge of the lake, with grade gradually reducing away from the lake.
The highest brine SOP grades of up to 20,000mg/L SOP occurred on the western end of Lake Sunshine at depths greater than 60m near the lake’s edge.
Kalium’s development of the Beyondie project will see operations commence at 90,000 tonnes per annum SOP and ramp up to 180,000tpa SOP for domestic and international sale.
Located over approximately 1,760 square kilometres, the project comprises 16 granted exploration licences, 15 miscellaneous licences, two mining leases and a gas pipeline licence.
Kalium Lakes is developing the sub-surface Lake Sunshine brine deposit to produce an SOP product, via an evaporation and processing operation.
In October, the company announced it had achieved the final investment decision milestone and would proceed to construction stage with Australia’s first SOP production targeted for 2020.
At midday, shares in Kalium were steady at $0.47.