Vulcan Energy: A Reservoir Test, an Adsorbent Plant and a Stake Disclosure That Is Not a Share Purchase

Vulcan Energy has moved on two separate technical fronts in recent weeks, and neither of them amounts to proof that Lionheart is up and running. The company has underpinned a key planning assumption with a well test and has begun making one of its own operating materials. A stake disclosure from Citigroup, meanwhile, tells a different story entirely, and investors who read it as a large investor buying in are reading past what the filing actually says.

What the LSC-3a test does and does not show

The reinjection well LSC-3a was reported roughly a week ago. Under the planned operating conditions, the estimated reinjection capacity came in at about 64 standard litres per second. The Lionheart development plan had assumed roughly 40 standard litres per second.

Vulcan describes the result as confirmation of a material planning assumption and as a reduction in subsurface uncertainty. It marks the first time a test has demonstrated reinjection into a highly permeable section of the reservoir, and the findings are to feed into the planning of further wells.

The scope of the claim matters as much as the number. What was measured is the capacity of a single well under the conditions it is meant to operate in, which firms up the basis for developing the wider field. A successful individual test is not the same thing as commissioning the whole Lionheart project. Nor does it say anything about revenue or profit actually booked. The figure is a capacity derived from the test, not a record of output already produced.

Adsorbent production gets under way in Germany

A second preparatory step was announced on 8 October. Commercial-scale production of Vulcan's own VULSORB adsorbent has started in Germany. Working with a manufacturing partner, the company intends to prepare the initial fill of the extraction columns for the planned start-up in the second half of 2028.

VULSORB is used to extract lithium from geothermal brine, so the production start concerns a material for the later extraction process. It does not mark the beginning of commercial lithium output at Lionheart. The two announcements cover different prerequisites of the same project: the well test yields knowledge about the subsurface, while the adsorbent production readies the technical side of the process. What they share is that both de-risk execution.

Citigroup's higher stake is not a purchase

Roughly two weeks ago, Citigroup's reported voting rights in Vulcan rose from 7.1056% to 8.1917%. The mandatory disclosure attributes the interests shown to securities lending and customary market contracts. A higher percentage therefore does not establish a direct share purchase made as an investment decision, and treating the filing as an unambiguous vote of confidence from a major investor goes beyond its content. What counts here is not just the direction of the change but the contractual background behind it.

On the market, the stock posted a daily move of -2.3% yesterday. The technical project news and the holdings notification each carry their own information, and neither offers a direct explanation for that price action.

The next fixed checkpoint

The next scheduled date for assessing the project's state is 28 October 2026, when the September quarterly report is due for publication. For investors, the task is to keep the individual steps achieved so far separate from the full operation that still lies ahead. The technical confirmation and the adsorbent output now under way are concrete progress, but their weight is tied to the specific component tested or started. That distinction is what matters when sizing up Vulcan Energy.