Lion One's Shrinkage Stoping Trap: Why Labor-Intensive Costs and a 5-Month Lag Block Near-Term Upside

Shrinkage stoping is a technique that fits Tuvatu's geology, but it comes with a trade-off for the gold supply chain. The method is designed for steep, narrow ore bodies with strong walls, which aligns with the characteristics of the Ura1 and UR2 lodes at Tuvatu. In this approach, miners work from the bottom up, blasting ore that is then left in place to form a working platform and provide wall support. This is a vertical overhand method, typically used where the ore body dips more than 50 degrees and has regular boundaries. The key requirement is that the broken ore must not degrade when stored in the stope, and the surrounding rock must be competent enough to hold its shape. For Tuvatu's narrow veins, this method is often the only practical option when other techniques are uneconomical or impossible.

The trade-off is clear in the method's execution. Shrinkage stoping is labor-intensive and cannot be readily mechanized, which directly contributes to higher unit operating costs. Miners must manually drill, load, and blast in confined spaces, then periodically draw off some of the broken ore to make room for the next round. This process is inherently slower and more complex than automated methods, creating a production cadence that is steady but not rapid. The safety risks are also elevated due to the confined working environment and the need to manage unstable broken rock. For the commodity balance, this means the mine's contribution to the gold supply pipeline is reliable but constrained by this slower, more costly rhythm.

The first stope's production metrics provide concrete evidence of this method in action. In the third quarter of 2025, Lion One completed its first shrinkage stope, yielding 5,704 tonnes at an average gold grade of 10.60 g/t. This result confirms the technique is being applied as planned. However, it also sets the baseline for what can be expected from this labor-intensive process. The subsequent development of a second, larger stope and a third under construction shows the company is scaling up, but the fundamental production cadence-driven-by the physical demands of the method-will continue to shape the mine's output profile and its cost structure for the foreseeable future.

Production Flow and Financial Metrics

The path from rock to gold at Tuvatu is a deliberate, multi-stage process that introduces a predictable lag. The company's update confirms that gold production in February came from ore mined earlier in the quarter, a lag of three to five months from the start of stoping. This delay is a direct consequence of the mining method. After blasting, the broken ore is left in place to support the stope walls and serve as a platform. Only after sufficient ore has accumulated is it drawn down and transported to the surface for processing. This sequential, labor-intensive rhythm means that the financial impact of a new stope's start is not immediate; it unfolds over several months as the ore is gradually processed.

This staged approach is clearly visible in the mine's development plan. The company is not mining in parallel but is instead building a pipeline of stopes. The successful completion of the first stope in Q3 2025 was followed by the development of a second, larger shrinkage stope projected to be twice the size in Zone 5. Now, a third shrinkage stope is under development at the 1120 level. This sequential mining strategy ensures a steady flow of ore into the mill, which is critical for maintaining a reliable supply of gold. It also allows the company to refine its designs based on new geological data, as seen in the additional surface drilling for the third stope. However, it also means that the mine's production ramp-up is tied to this physical cadence, not a faster, more mechanized one.

On the processing side, recent capital expenditure has yielded a tangible efficiency gain. The company's flotation plant, a key upgrade aimed at improving gold recoveries, was completed under budget by A$400,000. This cost control is a positive signal for the operation's financial discipline. More importantly, the plant's commissioning is expected to improve recovery rates materially. Higher recoveries directly translate to more gold extracted from the same tonnage of ore, which is a powerful lever for reducing the unit cost of production. In the context of a labor-intensive mining method, optimizing the processing stage becomes even more critical for overall cost efficiency.

The bottom line is a mine operating on a measured, physical timeline. The three-to-five-month lag between mining and gold output creates a predictable but slow-moving production flow. The sequential development of stopes ensures a steady supply of feed for the mill, but it also caps the speed of any near-term output surge. The under-budget flotation plant is a bright spot, offering a clear path to improve recoveries and lower costs. For investors, this setup means the financial metrics will reflect the underlying production cadence-steady but not explosive-while the focus remains on executing this plan efficiently.

Supply Dynamics and Scalability Assessment

The mine's current output confirms a steady, modest flow. In February, Lion One produced 813 ounces of gold at an average grade of 3.49 g/t. Year-to-date, that totals 9,180 ounces. This is the tangible result of the sequential, labor-intensive mining cadence. It is a reliable supply, but it is not a surge. The broader gold supply context is one of tightness, where every ounce of new production matters. Yet Tuvatu's contribution, while welcome, is a small piece of the global puzzle, and its growth path is defined by physical constraints, not market demand.

The primary limit on scalability is the inherent labor intensity of shrinkage stoping. As a method, it cannot readily be mechanized and is labor intensive. This is not a minor operational detail; it is the fundamental bottleneck. Scaling output means scaling the workforce and, more critically, managing safety in confined, complex stopes. The company's plan to develop a second, larger stope and a third under construction is ambitious, but its execution will be a function of how many miners can be safely deployed and how efficiently they can work. The physical rhythm of the method-blasting, waiting for ore to accumulate, then drawing it down-sets a natural ceiling on how quickly new tonnage can be processed. Meeting production targets here is less about capital expenditure and more about human capital and operational discipline.

To support this scaling, the company is investing in better data. The recent upgrade to its drill fleet aims to improve data acquisition speed, a critical foundation for mine design. The goal is to tighten geological knowledge, particularly for the third stope, to avoid the earlier design shortcomings. Better data leads to more accurate grade control and optimized stope designs, which can improve recovery and reduce waste. In the long run, this could help maximize the value extracted from each tonne of ore. But for now, the immediate pressure is on the existing, slower production flow. The drill fleet upgrade is a forward-looking investment in efficiency, but it does not change the fact that the mine's current output is being pulled through a narrow, labor-intensive bottleneck.

Catalysts, Risks, and What to Watch

The immediate path forward hinges on the successful completion of the second and third shrinkage stopes. The company's plan is clear: a second, larger stope was developed in Zone 5, and a third is now under development at the 1120 level. The successful drawdown of these stopes is the primary catalyst for confirming the mine's ability to meet its production targets. Each completed stope represents a tangible step in the sequential mining pipeline, directly feeding ore to the mill. Any delay or setback in these developments would directly impact the steady but slow production flow that has been established.

The most significant risk to this timeline is the method's inherent safety profile and the potential for delays if ground conditions demand more cautious development. Shrinkage stoping is a very labor-intensive method conducted in confined spaces where miners work overhand, blasting and then periodically drawing off broken ore. This creates a complex, unstable environment that requires constant ground control. If the company encounters weaker rock or unexpected ground instability during development, it may need to slow the pace, implement additional support, or even redesign a stope. Such adjustments, while necessary for safety, would introduce delays and could disrupt the planned cadence of ore production.

A key watchpoint for long-term efficiency is whether the recent drill fleet upgrade leads to faster, more accurate stope designs. The company has acknowledged that the first stope could have been more accurately designed with better geological data, a lesson it is applying to the third stope with additional surface drilling. The upgrade to a new fleet of high-performance underground and surface rigs aims to improve data acquisition speed and quality. If this investment pays off, it could tighten geological knowledge, reduce design errors, and optimize stope parameters. This would improve grade control and recovery rates, directly boosting the value extracted from each tonne of ore. For now, the focus remains on executing the current stopes safely and efficiently, but the success of this drilling initiative will be a critical factor in scaling the operation beyond its current labor-intensive bottleneck.