Key Highlights:

  • Boab Metals (ASX:BML) has commenced Phase IX drilling at the Sorby Hills Silver-Lead Project.
  • The program includes up to 5,000 metres of drilling across approximately 45 holes.
  • Drilling will focus on reserve conversion, silver-focused resource expansion, the Beta Deposit and the Keep Prospect.
  • The Beta Deposit hosts an Inferred Mineral Resource of 3.3Mt at 61g/t silver, 4.6% lead and 0.4% zinc.
  • Boab will also begin exploration drilling at the 100%-owned Manbarrum Zinc-Silver-Lead Project.

 

Perth-based developer Boab Metals Limited (ASX: BML) has formally re-opened the drill book at its flagship Sorby Hills Silver-Lead Project and is, for the first time, drilling at its 100% owned Manbarrum Zinc-Silver-Lead Project nearby. The Phase IX drilling campaign at Sorby Hills, announced on 13 May 2026, marks the next stage of exploration following the project's transition into development and construction after a Final Investment Decision taken in December 2025.

The 2026 program is designed to support both near-term mine optimisation and longer-term resource growth. Boab has flagged a particular focus on extending mine life, lifting confidence in existing resources and unlocking additional silver upside across the broader project area. Drill rig arrival on site is scheduled for 22 May 2026.

Program structure: what Phase IX will test

The Phase IX program is structured around four main work streams. The first is resource-to-reserve conversion drilling, in which infill and tighter drill spacing along the margins of known mineralisation are used to upgrade portions of the Mineral Resource to higher confidence categories. The company has stressed that this work is not a requirement for drawdown under its project finance Debt Facility but is expected to support detailed mine planning and production scheduling.

The second work stream is silver-focused resource expansion drilling. Boab has flagged that previous mine planning was based on lead-only cut-off assumptions, and that some areas of strong silver grade were excluded as a result. Drilling will deliberately target these zones with the goal of incorporating additional silver-bearing material into future mineral inventories.

Third, the campaign includes follow-up drilling at the high-silver Beta Deposit, which Boab regards as a compelling opportunity for future mine-life extension. The current Mineral Resource for Beta is 3.3 million tonnes at 61g/t silver, 4.6% lead and 0.4% zinc, classified as Inferred due to limited drilling density and structural complexity. Beta has not previously been incorporated into the Sorby Hills mine plan because earlier development efforts prioritised deposits sitting within the Environmental Protection Authority (EPA)-approved development footprint to streamline approvals and timelines.

Fourth, drilling will continue to test the Keep Zinc-Lead-Silver Prospect, a seismic target located approximately two kilometres south of the current Sorby Hills reserve base. Results from earlier campaigns have, according to the company, validated its geological interpretation and reinforced the prospectivity of the broader Burt Range Basin. The Phase IX campaign will represent the third round of drilling at Keep.

Beyond Sorby Hills, the program also includes greenfield exploration activities at Manbarrum, targeting historical zinc-soil anomalies that remain largely untested by drilling and assessing the broader potential for new discoveries within the project area.

Headline milestones

Boab has spelled out a clear set of milestones for the campaign. The initial program is up to 5,000 metres across approximately 45 drill holes. The Phase IX campaign is expected to run for roughly three to four months. Assay results are anticipated from early Q4 2026. The program is focused on resource growth, reserve conversion and mine-life extension, with significant emphasis on additional silver potential across the Sorby Hills system.

Management commentary

Boab Managing Director and CEO Simon Noon framed Phase IX as a deliberate move into the next phase of the asset's evolution. "Sorby Hills has now entered the next phase of its evolution as a Mining project, and our exploration strategy is increasingly focused on identifying opportunities to extend and enhance the long-term value of the operation," he said.

Mr Noon highlighted the importance of testing lower-confidence ground around the existing resource. "The Phase IX drilling program is an important step in that process. The campaign will focus on lower-confidence areas around the fringes of the existing resource, particularly down-dip extensions that have been further supported by recent success at the Keep Target."

He also drew specific attention to the silver theme. "We are also excited by the opportunity to further assess the high-grade silver potential at Beta and continue testing the broader exploration upside across the Burt Range Basin."

The Beta Deposit in detail

Beta sits centrally in Boab's longer-term growth narrative. With a current Mineral Resource of 3.3Mt at 61g/t silver, 4.6% lead and 0.4% zinc, it hosts some of the highest silver grades identified across the Sorby Hills Project. The Phase IX campaign has been specifically designed to improve confidence in the geometry and grade continuity of the deposit, which currently remains in the Inferred category due to drilling density and structural complexity.

Boab's interest in Beta is partly strategic. Earlier mine planning effectively bypassed the deposit in order to keep the project's permitting pathway clean and inside the EPA-approved footprint. With construction now under way and the project's permitting framework established, the company believes Beta represents a relatively low-risk opportunity to materially increase the scale and longevity of the Sorby Hills operation while enhancing the project's silver exposure.

The Keep Target

The Keep Zinc-Lead-Silver Prospect is described by Boab as a compelling exploration target with significant discovery potential outside the existing Sorby Hills resource base. The upcoming third round of drilling will further test the scale, continuity and broader mineralised potential of the system. The company has stated that continued success at Keep could establish an entirely new mineralised corridor outside the currently defined Sorby Hills resource.

Manbarrum

In parallel, Boab plans to advance exploration at the 100% owned Manbarrum Zinc-Silver-Lead Project, located approximately 25 kilometres east of Sorby Hills. The planned program will target historical zinc-soil anomalies that remain largely untested by drilling and assess the broader potential for new discoveries and future resource definition within the project area. The announcement does not include detailed drill hole totals, target grades or expected metallurgical work for the Manbarrum component; further information was not provided.

Project context

Sorby Hills, located approximately 50 kilometres from Kununurra in Western Australia, has excellent access to existing sealed roads for transporting concentrate 150 kilometres to Wyndham Port. Following the Final Investment Decision taken in December 2025, the company is advancing the project toward first concentrate production in the second half of 2027. Boab has framed its development as positioning the company to capitalise on what it describes as strong silver and lead market fundamentals.

Why this matters for investors

For Boab shareholders, the Phase IX campaign brings together several themes that are likely to be relevant in the lead-up to first concentrate production. Reserve conversion drilling could provide upgrades to mine planning inputs. Down-dip and silver-focused resource expansion drilling could lift the mineral inventory beyond the current DFS and FEED study assumptions. Follow-up at Beta could surface a previously sidelined high-grade silver opportunity. Continued work at Keep could expand the exploration frontier beyond the current resource base. Greenfield activity at Manbarrum could establish a second exploration leg outside the Sorby Hills system.

Investors should keep in mind that the results released to date with this announcement are operational, not assay-based. The release flags newsflow from early Q4 2026 onward, when first assay results are anticipated. Until then, drill program updates rather than mineral resource updates are the likely cadence.