Red-letter day as Peninsula restarts Wyoming yellowcake production

In a red-letter day for Peninsula Energy, the company has flicked the switch back on at its Lance uranium operation in Wyoming, USA, with the project’s central processing plant (CPP) once again producing dried yellowcake.

The company says its plant has renewed uranium precipitation following the installation and commissioning of replacement agitator assemblies in both precipitation tanks, restoring the final stage of its processing circuit to full working order. 

Notably, Peninsula has maintained its calendar year 2026 production guidance unchanged at between 0.4 and 0.5 million pounds of uranium, underpinned by a hefty 2.0 million pounds per annum nameplate plant capacity.

The restart follows Peninsula’s mid-February update, which disclosed incorrect installation of the dual precipitation circuit agitator assemblies. This required temporarily taking the plant offline during its early ramp-up phase. 

Usefully, the rectification has been dealt with as a warranty claim under the company’s engineering, procurement and construction contract.

Before the temporary shutdown, the precipitation circuit had shown strong operational performance, achieving just shy of 100 per cent efficiency during its early ramp-up phase. 

Now, with rectification complete, Peninsula says it is confident that its CPP is well-placed to support sustained production ramp-up through the remainder of the year.

Peninsula Energy managing director and chief executive officer George Bauk said: “The successful recommencement of precipitation and yellowcake production at the Lance CPP is an important milestone for the Company. The team responded quickly and effectively to resolve the installation issue, while maintaining wellfield operations and progressing other optimisation activities across the plant.”

While the plant was down, Peninsula made productive use of the downtime, carrying out a series of plant improvements and optimisation works to tidy up and fine-tune operations across the facility.

The work included progressing its coating work across the ion exchange and elution tanks in phases one and two and installing a small reverse-osmosis (RO) unit to improve process water quality for the filter press wash cycles.

The newly installed reverse osmosis unit is designed to improve the quality of the final yellowcake by stripping out excess sodium, while also lowering the risk of corrosion across plant equipment.

While the reverse osmosis upgrade might seem like a minor detail, it ties directly into Peninsula’s broader operational “reset” at Lance. 

High sodium levels in ISR uranium processing can stem from saline groundwater or from alkaline leaching reagents such as sodium carbonate, bicarbonate or sodium hydroxide, which can ultimately reduce precipitation efficiency and lower yellowcake quality. 

Peninsula’s reset plan has therefore centred on shifting the operation away from alkaline chemistry towards an acidic leaching system, a change designed to improve recovery performance and product quality while also reducing sodium-related processing issues.

The shift to acidic leachants has dramatically increased peak uranium grades - averaging nearly one gram per litre-  and impressively, has improved overall recoveries to over 90 per cent. 

The change also reduced operating costs. Acidic leaching can offer lower operating costs and higher efficiency than alkaline methods at certain sites. 

This may have also partly come about because the Lance project is geologically more compatible with acidic solutions, which often leads to processing a greater percentage of uranium minerals in a shorter timeframe. 

On the wellfield side, momentum has continued to build in Mine Unit 4, which is the key growth engine in the company’s production reset plan. Uranium-bearing solution from Header House 14 in Mine Unit 4 was sent to the plant in late March and is now being captured on resin in the ion exchange columns. 

Early data are encouraging, with the average head grade into the plant since connection at 63.9 milligrams per litre (mg/l), which the company says is well ahead of historical grades delivered under the project’s prior alkaline chemistry operations. 

Peninsula says the grade uplift came quickly, within one week of entering production after only three pore volumes, with targeted peak average header house grades expected after four to five pore volumes. 

The company is continuing to acidify additional header houses in Mine Unit 4, in line with its reset plan, as it pushes towards a stabilised, steady run-rate for the rest of the year.

With the processing plant back online, its guidance intact and Mine Unit 4 seemingly finding its stride, the company looks to have its Lance ramp-up back on the rails. 

Now, Peninsula’s story hinges around maintaining the resin loading, precipitation and drum-filling sequence humming smoothly as the company eyes its next leg up in domestic US uranium supply.

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