Australian Potash closing in on SOP ore reserve

Australian Potash has made its thickest intersection of productive basal sands whilst drilling two production bores at its Lake Wells sulphate of potash, or “SOP”, project near Laverton, WA.

The second bore intersected 62m of high-yielding sands in the target palaeochannel and has flowed brine at indicative rates above the project requirement of 15 litres per second.

These production wells will play a key role in defining an ore reserve estimate for the project that will, in turn, feed into the Definitive Feasibility Study.

Diamond drilling to recover basement core rock for permeability testing has also been completed.

The company added that it had completed the evaporation pond construction program and expected first fill to begin within two weeks.

Managing Director Matt Shackleton said: “Central to the final field program at Lake Wells is the push to a JORC ore reserve estimate, and our focus is on building upon the more than 50,000 metres of drilling and already extensive database of test work…”

“Developing these two additional production wells, test-pumping them, and collecting bed-rock core for analysis are critical factors that will feed into the calculation of an ore reserve estimate for Lake Wells.”

“APC’s extensive geotechnical field and test-work at the project have confirmed the existence of a uniform, flat-lying layer of low permeability clay at the lake surface that can accommodate ‘on-playa’ evaporation ponds.”

“Because of this, we can avoid the significant capital expenditure required to line the pre-concentration ponds. The final geotechnical field trials will allow us to establish the optimal commercial-scale pond design, in terms of cost of construction and effectiveness of the plan.”

Since Australian Potash calculated its JORC mineral resource of 14.7 million tonnes of contained SOP, most of which is in the higher confidence indicated category, for Lake Wells in March 2017, the company has carried out 4,266m of brine drilling, including two production wells, diamond core and several monitoring bores to assess aquifer response during test pumping.

The company has also collected 52,600m of passive seismic data, which improved its understanding of the Lake Wells palaeovalley model and facilitated identification of drill targets.

Lake Wells is located 280km by road from bulk rail terminals near Leonora in the northern WA Goldfields region.

Pilot processing has already proved that Australian Potash can produce a high-grade SOP with a purity of 98% from the Lake Wells brines.