Estrella Kicks Off Limestone Drilling in Timor-Leste as it Chases Giant Resource Target

By all accounts, Estrella Resources (ASX: ESR) is charging hard in Timor-Leste, and now the drill bits are ready to spin at its Werumata limestone project. Fresh off the back of receiving the final tick of approval from the Timor-Leste Minerals Authority, the junior explorer has begun earthworks in preparation for a 26-hole RC campaign aimed squarely at delineating a whopper of a limestone resource.

And it’s not just any old limestone Estrella is chasing. The company is targeting a 500 million dry metric tonne inferred resource of high-purity calcite-rich rock – a milestone that would unlock the next stage of a “transformational” partnership with Indonesian mining services firm PT Raka Energi Mandiri (REM).

The Rock Star of Industrial Minerals

Estrella’s MD Chris Daws, never one to underplay a good story, is bullish on the region’s potential:

“Our work to date suggests Werumata consists of a large sheet of high-purity limestone which resides close to existing infrastructure and a potential port development option,” he said, noting the limestone’s potential for use in industrial pH control and environmental applications.

Drilling will initially test a series of plateaus just south of Uero-Mata township, with follow-up diamond holes and infill work to be staged based on early results. The company believes it is drilling into the Baucau Formation – a thick, clean, calcite-rich limestone known for its impressive acid-neutralisation capacity.

Recent assays from surface sampling back up the theory. Ten samples returned calcium carbonate contents between 74.5% and 93.4%, with net neutralisation values pushing as high as 944 tCaCO₃/1Kt – numbers that will no doubt whet the appetites of Asian industrial consumers.

The REM Deal – Ambitious but Structured

Estrella’s limestone push is underpinned by a May Master Agreement with REM, which grants the Indonesian group exclusive rights to market and offtake limestone into Indonesia. The deal is laden with upside – up to 500 million tonnes over five years, with Estrella to issue one unlisted option at $0.05 for every tonne sold.

But it’s a deal that demands delivery. The company must satisfy a series of milestones before the definitive offtake kicks in, including:

• A 500Mt JORC-compliant limestone resource

• A positive scoping study

• All environmental and export approvals

Those timelines have already been pushed back once – with the JORC target now due by 30 November 2025, and mining/export permits required by March and June 2026, respectively.

That Estrella is already building tracks and pads ahead of the drill rig’s mobilisation in mid-October signals a company keen to make up for earlier delays – something Daws admits were caused by internal resources being diverted to its manganese play at Ira Miri.

“We anticipate a rapid re-acceleration in our limestone activities to meet the revised timeframe,” Daws said in August, emphasising that the geological model of a thick, homogeneous limestone sheet lends itself to a swift resource definition campaign.

Calcite Demand – A Timely Pivot?

It’s no accident Estrella is pivoting hard into limestone. The company is betting on rising regional demand – particularly in Indonesia – where calcite is increasingly used as an environmental buffer in nickel refining, among other industrial applications.

Global calcite consumption is forecast to rise from US$5 billion in 2023 to more than US$8.1 billion by 2032, with Southeast Asia emerging as a key growth engine. Tightening environmental standards and Chinese supply pressures are likely to keep regional buyers sniffing around for secure, high-grade sources.

In that context, Werumata’s location – near potential port sites and existing infrastructure – could prove a critical logistical advantage.

Dual Commodity Play

The limestone isn’t just valuable in its own right. It also overlies Estrella’s manganese target – the Noni Formation – meaning drill dollars are doing double duty. Estrella’s plan to chase both commodities with overlapping drilling campaigns may offer cost efficiencies not often seen in frontier exploration.

The Road Ahead

With approvals in hand, pads under construction and a drill rig in transit, the next few months will be crucial for Estrella. Investors should expect a steady flow of news as drilling ramps up – and eyes will be firmly on whether those early holes support the scale and grade required to hit that 500Mt resource mark.

Should Estrella deliver, it would mark a rare feat: transforming surface limestone into a strategic industrial asset with regional relevance. Whether or not it reaches that lofty target, it’s clear the company isn’t sitting idle.

Or, as Daws more succinctly put it:

“Momentum continues to build. Go Estrella!”.