Salt Lake Potash successfully completes unlined pond trial
Salt Lake Potash Limited (DI)
2.45p
15:48 19/11/21
Salt Lake Potash confirmed the successful completion of field trials testing an on-lake, unlined evaporation pond model on Monday, which it said would result in “significant” capital expenditure savings for the Goldfields Salt Lakes Project (GSLP).
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The AIM-traded company said the field trial involved the construction and testing of four test ponds on the Lake Wells Playa, built solely from in-situ clay materials, using a standard 30t excavator, which it said operated “efficiently and effectively” on the lake playa.
It said the trial achieved levels of brine seepage from the evaporation ponds well below the threshold for successful operation of halite evaporation ponds, and potentially also for the smaller potassium salt harvest ponds.
The capex savings from that construction method would be “substantial” compared to the alternative of plastic lined ponds, Salt Lake’s board said.
Its engineering consultant, Amec Foster Wheeler, estimated the cost of lined ponds to be approximately $10.50 per square metre, up to 25 times higher than construction costs for unlined ponds.
The 25m x 25m test ponds were designed by SLP's geotechnical consultant, MHA Geotechnical, to test the constructability and operating performance of a number of pond wall designs and to provide reliable seepage data under site conditions.
SLP said the observed brine loss in the test ponds was well within the parameters of the hydrodynamic model, inferring losses for a 400Ha pond would be below 0.125mm/day.
The company said it identified “several opportunities” to improve the construction of commercial scale ponds using excavators, along with ancillary equipment to optimize drying and compaction of the clays utilized in pond wall construction.
That should result in further improvements in the already very low seepage observed in the trial sized ponds.
SLP said it planned to now construct an 18Ha Pilot scale pond system to further improve the pond design and construction model.
“We are very pleased to have successfully demonstrated and quantified the potential for on-lake, unlined evaporation ponds at the GSLP,” said CEO Matt Syme.
“The importance of this outcome cannot be understated for two reasons - firstly, the potential capex savings are very substantial; and secondly, this outcome is the final fundamental technical building block which we have tested and validated under field conditions and to a very high standard.
“Along with all of the company's other high quality testwork on brine extraction and evaporation and the conversion of on-site harvest salts to high quality SOP, as recently validated and optimised by Saskatchewan Research Council, we believe we have rigorously tested all the technical elements of SOP production from salt lake brines to a standard not seen in Australia to date.”