Mosman’s helium exploration focus is Southwest and Southeast Colorado, which has significant concentrations of helium and historical helium production.
Dual target helium and hydrocarbons is a significant commercial benefit (such as Sagebrush which has oil production and revenues) Mosman’s established helium infrastructure provides opportunity for early production and sales.
- Sagebrush project
(Mosman 82.5%) - Coyote Wash Project
(Mosman 100%) - Cinnabar Lease
(Mosman 75%) - Vecta Project
(Mosman 20%)
Across Sagebrush and Coyote Wash we are executing at pace. At Sagebrush, seismic acquisition planning is well-advanced and we are targeting an early-October start, while Sproule’s independent verification is moving toward economics and final reporting. At Coyote Wash, the IMDA package has been updated and resubmitted, with our BIA meeting set for early September. In parallel, our facilities workstream is progressing with credible vendors. These steps build on the recent Tribal approval for Sagebrush 3D seismic and position Mosman for a material period of newsflow and value-driving activity.
Howard McLaughlin, Interim-Chief Executive
Stable investment area
OECD (incl. USA)
High helium %
Significant commercial benefit
Established infrastructure
Drilling costs
Moderate drilling costs
Established production
Acquired three initial projects
Low entry costs with high potential
Net Production attributable to Mosman in the year to 30 June 2024 was 16,340 boe, compared to 31,067 boe in 2023. The decrease in net production was primarily due to lower production at Cinnabar, which was somewhat offset by increased production at Stanley.
| Gross project production, BOE | Net production to Mosman, BOE | |
|---|---|---|
| Stanley | 31,500 | 11,503 |
| Cinnabar | 2,494 | 1,869 |
| Livingston | 2,093 | 419 |
| Winters | 5,513 | 1,286 |
| Arkoma | 5,645 | 1,263 |
| 47,245 | 16,340 |
A summary of the current oil and gas projects as at 30 October 2024
| Asset / project | Mosman interest | Location | Status |
|---|---|---|---|
| Vecta helium project | 20% | Colorado | Terminated |
| Cinnabar | 75% | Texas | Producing |
| Cinnabar extended | 78% | Texas | Undrilled |
| Arkoma | 27% | Oklahoma | Producing |
Sagebrush Project
Sagebrush is a large acreage position of 10,000 acres, split between the South area comprising 2560 acres and the North area 7440 acres, with existing oil fields and helium encounters in the area.
The Sagebrush Project is in the Four Corners region in Colorado, US which is an area of established helium production from the Leadville formation carbonates from fields such as Doe Creek, 50 miles to the north of the Sagebrush Project.
The Sagebrush Project current oil production is circa 40 bopd (gross) from 7 wells which enable the 10,000 leased acres to be Held By Production. Mosman has existing well data, oil production records and seismic data and recently received test data from the Sagebrush-1 well drilled in 1993 from the previous operator where a drill stem flow test (“DST”) conducted in the Leadville Formation flowed gas with 2.76% helium, 34.5% nitrogen, 39.9% carbon dioxide, 19.5% methane and circa 3% other petroleum gases.
At current market prices, the main value of the gas is the helium. The hydrocarbons may have value either for sale or avoiding costs by onsite power generation
The Sagebrush project includes midstream and upstream infrastructure available for helium and natural gas. An existing pipeline joins the Sagebrush/Coyote Wash areas to the Lison Helium/Gas plant, and while the Colorado section is currently not in use, it can be reactivated.
Mosman has also been assessing options for surface facilities required to process helium once production is established. Initial reviews of plant design and fabrication timelines have been encouraging, with no technical impediments identified. This early work is important to ensure that Mosman can move quickly from successful well testing into commercial helium sales, by aligning subsurface development with a practical and scalable surface solution.
Highlights
In May 2025, Mosman announced the first estimate of helium and hydrocarbon volumes at the Sagebrush Project.
- Maiden C2 net best estimate Contingent Resources of 205 million cubic feet (mmcf) of helium and 1.7 billion cubic feet (bcf) of hydrocarbon gases at the Sagebrush Project as determined by Mosman utilising a report from Four Corners Helium LLC (“FCH”) dated 5 May 2025 in which seismic interpretation indicates a structural closure of circa 585 acres and estimates the initial gas in place volume as 18.4 bcf and recoverable gas volume to be 11 bcf (“FCH Report”).
- The combination of existing wells, flow tested helium and hydrocarbons, oil production infrastructure and an existing gas pipeline provide the ingredients to move in stages to a potential fast track helium and hydrocarbon development at the Sagebrush Project.
- The fast-track development potential is in addition to the significant exploration prospects identified by seismic at both the Sagebrush Project and the adjacent Coyote Wash Project.
- On 26th August 2025, Mosman announced it has reviewed bids for the planned 3D seismic survey at Sagebrush, which is expected to cover approximately 16 square miles. The programme is anticipated to commence in early October, subject to final contracting and mobilisation. The seismic data will provide a much higher-resolution picture of subsurface structures and potential helium and oil traps than currently available, significantly de-risking future drilling. By mapping fault blocks and closures in detail, Mosman aims to refine future drilling targets and optimise well placement, providing confidence in both helium and hydrocarbon prospectivity.
Resource estimate
Mosman has utilised the FCH Report to estimate net C2 Best Estimate Contingent Resources. The resource assessment has been conducted in accordance with standard principles of Petroleum Resource Management (PRMS) which specifically applies to oil and gas reserves and has been deemed suitable for helium by the SPE.
Mosman notes the relevant reservoir zone has been drilled, logged and demonstrated to flow and the existing well is cased and cemented across the relevant zones, and that seismic data has been interpreted to determine the size of the structure. However, more work is required to demonstrate the optimal development, costs and markets, and is currently insufficient to assess commerciality. Work has already started to be able to determine commerciality and to be able to make a final investment decision (“FID”) with the initial objective to put this well on production and thereafter determine the commerciality of additional development wells.
Contingencies
The FCH Report notes the potential for a dual target Ismay oil and Leadville helium prospect, based on seismic interpretation. This is significant as it may enhance the economics of drilling and development of the Sagebrush Project.
The FCH Report notes that the Sagebrush-1 well reported fluorescence in the Lower Leadville, and this zone has not been included in the resource estimate as it was not flow tested.
The FCH Report also notes that the Sagebrush-1 well provides important data for assessing the Coyote Wash Project, especially as it confirms the presence of helium and the reservoir potential of the Leadville formation in this area.
Future work plan
In addition to the plans to acquire 3D seismic, the current basis for near term planning is expected to include an extended flow testing of the Leadville formation at the Sagebrush-1 well. This may also include flow testing the Lower Leadville formation.
Work has already started on a development plan that is anticipated to take several months to determine the commercial feasibility of development.
Coyote Wash Project
Mosman holds a 100% working interest across the project area of 4320 acres, with 3D seismic coverage over the entire project area. Historically, Coyote Wash 30-12 was drilled by Wintershall in 1984, with tested non-flammable gas results.
Today, Mosman has identified six large helium prospects identified with 3D seismic targets consisting of helium within pre-salt Leadville Carbonates and McCracken sandstones, plus overlaying oil potential in Ismay Fm.
Cinnabar Lease
Mosman has a 75% working interest in the circa 350 acre Cinnabar Lease in East Texas.
There are two wells that have produced oil since the 1980s. In 2022, Mosman drilled the Cinnabar-1 successfully to a depth of 9,900 feet. Multiple oil bearing Wilcox Sands from 9,050 feet to 9,850 feet.
Subsequently, an updated Reserve Report was commissioned. The details of which are stated below (thousands of barrels of oil equivalent “MBOE”):
| Proved Developed Producing | Proved Developed Behind Pipe | Proved Undeveloped | Total Proved | Total Probable | Total Proved Plus Probable |
|---|---|---|---|---|---|
| 302 | 147 | 1,132 | 1,581 | 65 | 1,646 |
This Reserves Report was prepared by a third-party independent petroleum engineering firm and conforms to SPE-PRMS petroleum guidelines. The royalties on the lease are circa 25%.
Vecta Project
Mosman acquired a 10% interest in Vecta Helium Project for US$0.5m in June 2024, before acquiring a further 10% for shares (market value US$0.5m) in July 2024. Vecta benefits from an established infrastructure and structured fiscal regime via an experienced operator
With a proven high helium content gas production at nearby Model Dome Field (7-11%), Vecta consists of five identified helium prospects in the Lyons Fm across 51,000 net acre leases.
Further to its announcement of 27 June, Mosman announced the termination of its drilling campaign at the Vecta Helium Project following disappointing results from the first three wells.
The campaign, targeting the helium-rich Lyons formation at depths of 1200-1500 feet, included prospects in the Billy Goat AMI, BARD AMI, and Garcia AMI. Both the BARD and Garcia prospects encountered the Lyons formation deeper than anticipated, with water-wet conditions at the top and no structural traps as predicted by surface mapping.
These results indicate that surface mapping is not a reliable predictor of subsurface structures in this poorly explored region, which lacks seismic data and modern subsurface logs.
Under the agreement with its partners, Mosman disposed of its cost commitments in the Billy Goat AMI in exchange for a royalty on future revenue prior to drill results being obtained with zero cost to the Company, funded 100% of the drilling in the BARD AMI and 20% of the drilling in the Garcia AMI.
The remaining two planned wells incur no cost to Mosman, allowing the Company to exit the programme with minimal financial impact and no further payments. The total cost to Mosman of the drilling across the campaign was US$214,931.
Arkoma Stacked Pay Project
Held for sale.
Mosman’s wholly owned US subsidiary Mosman Texas LLC owns a 27% interest in the Arkoma Stacked Pay Project, located in Okfuskee County, Oklahoma. The Operator of the project is Inland Operating Company which also own an interest in the project together with a third party.