Peninsula Energy Ltd’s (ASX:PEN) (OTCMKTS:PENMF) (FRA:P1M) MU1A low-pH field demonstration test modifications for the flagship Lance Project in Wyoming, USA, have delivered favourable results including an increase in uranium recovery solution and improved response time in modified test patterns.
The company has implemented several test modifications to the field demonstration of low-pH In-Situ Recovery (ISR) since the previous update in late February designed to provide key data on pattern configurations, pH adjustment, acid consumption and oxidants ahead of a decision to restart production at the project.
Results indicate that Peninsula is closer to achieving target pH levels and that the new oxidant is beginning to deliver results.
“Happy with progress”
Managing director and CEO Wayne Heili said: “We are currently eight months into the field demonstration and are happy with how it is progressing.
“Adjustments made since our February update have delivered positive results.
“We will continue to run the field demonstration through the first half of 2022 and the information gained will be invaluable as the company progresses the Lance Project toward a return to commercial production.”
Revised pattern configuration
Three contiguous full-scale ISR patterns (injection wells feeding a centrally located production well) are operating within a previously unmined area of Mine Unit 1 (collectively MU1A).
The chemical parameters within the original field demonstration patterns responded to injection, but at a slower than optimal rate.
Peninsula Energy has adjusted the pattern configuration by installing and activating two new injection wells between each pair of recovery wells.
The result has been a considerably improved response for the key chemical parameters.
Once completed, the field demonstration will have generated comprehensive data on the influence of this design criteria, which will in turn inform the optimal design for commercial-scale production ISR patterns and the corresponding screen interval selection methodology.
Chemical parameter response
Achieving and maintaining the correct pH and oxidation-reduction potential (ORP) of the process solutions is paramount to successful uranium in-situ recovery operations.
At the time of the February update, only one of the demonstration patterns had reached the target pH of approximately 2.0 standard units.
Subsequently, and without further adjustment to acid solution addition rates or concentrations, the two lagging patterns have responded favourably, yielding a current composite recovery stream pH of 2.3 standard units.
The rate of pH response in the test patterns appears to have been a function of the selected pattern dimensions and design.
Pilot uranium recovery circuit
Although the target levels for pH and ORP have not yet been fully achieved, the uranium concentration in the field demonstration recovery stream is now responding positively to the current pH and ORP levels.
Since late February, the recovery stream uranium grade has doubled and is now in the 20 to 25 mg/L range, which is in line with expectations relative to the dimensions of the patterns and the number of pore volumes processed since commencing acidification.
With increasing uranium grades, Peninsula Energy has now activated the pilot ion exchange uranium recovery circuit.
Currently, the ion exchange circuit has not operated long enough to obtain meaningful performance data, however, a simple filtration system has been installed ahead of the pilot circuit in response to an event in which a suspended solids load was introduced to and blinded the resin beads.
Looking ahead
The company will continue technical evaluations related to the potential for application of membrane separation systems to enhance resin performance.
Enhanced resin loading has the potential to significantly reduce downstream processing and operating costs.
A laboratory-scale test is planned on production solutions from the field demonstration in the coming months.
Shares higher
Shares have been as much as 13.5% higher to A$0.13 and the company's market cap is approximately A$116.1 million.