Colosseum Bankable Feasibility Study Confirms High Margin Gold Project

A Technically Simple Restart with Strong Economics

SAN BERNARDINO, CA / ACCESS Newswire / May 11, 2026 / Dateline Resources Limited (ASX:DTR,OTC:DTREF)(OTCQB:DTREF)(FSE:YE1) (Dateline or the Company) is pleased to present the results of the Bankable Feasibility Study (BFS) for the 100%-owned Colosseum Gold and Rare Earth Element (REE) Project in San Bernardino County, California. The BFS demonstrates a robust gold development, generating significant margins.

Highlights

• US$1.08B undiscounted pre-tax free cashflow

  • Increases to US$1.357B using spot price

• US$785M NPV_5% (pre-tax)

  • Increases to US$999M using spot price

• 49.5%IRR (pre-tax) at base modelgold price (US$4,200/oz),

  • Increases to 59.5% using spot price (US$4,700/oz)

• US$249M of start-up capital (including US$16M of capitalised mining) plus US$25M contingency.

• 75koz average annual gold production of over first 6 years.

• 573koz total gold production over 10.4 year mine life

  • 102koz peak gold sales of in year 6.

• ~$55M increase in undiscounted pre-tax free cashflow for every $100/oz increase in gold price

• US$1,825/oz All-in Sustaining Cost (AISC) based on current industry costs within ±15%.

• Low 3:1 strip ratio highlights Colosseum's strong mining efficiency, with reduced waste movement supporting lower operating costs.

• 55koz of Inferred Mineral Resources within the pit shell that have not been included in the Ore Reserve.

• Additional underground potential in the northeast of the North Pit, that is open at depth and subject to ongoing drilling not included in Ore Reserve, including recently drilled holes.

Dateline's Managing Director, Stephen Baghdadi, commented:

"Since acquiring Colosseum in 2021, we have recognised the significant potential of the project. The near vertical nature of mineralisation associated with the breccia pipes demonstrates excellent continuity that continues with depth. Since the original Scoping Study was completed in October 2024, we have continued to see strength in the gold sector, with the project forecast to generate operating margins of greater than $2,500 per ounce.

"With the BFS complete and the Front-End Engineering Studies (FEED) well underway, our engagement with project financiers is advancing as we look to secure the funding required to commence production as soon as possible."

Operating and capital cost estimates in the Study are based on current industry costs and are considered to be accurate within ±15%.

Spot Gold Price (US$4,700/oz)

• Undiscounted free cash flow of $1,357M pre-tax and $978M post-tax.

• NPV_5% of $999M pre-tax and $704M post-tax.

• IRR of 59.5% pre-tax and 46.2% post-tax.

• All-in Sustaining Cost (AISC) of $1,838/oz.

Base Gold Price (US$4,200/oz)

• Undiscounted free cash flow of $1,082M pre-tax and $779M post-tax.

• NPV_5% of $785M pre-tax and $551M post-tax.

• IRR of 49.5% pre-tax and 38.6% post-tax.

• All-in Sustaining Cost (AISC) of $1,825/oz.

Gold Price Sensitivity

• Every $100/oz increase in gold price, increases undiscounted pre-tax free cash flow by ~$55M.

• Total gold production of 573koz.

• Peak annual gold production of 102koz in year 6.

• Average annual gold production of 75koz over first 6 years, before transitioning to stockpile processing.

• 2Mtpa carbon-in-leach (CIL) processing plant

• Metallurgical recovery averages 91% over life of mine

• 100% of ore (20.6 tonnes of ore at 0.95g/t Au) mined in first six years

• 11.5Mt at 1.34g/t Au processed during first six years, producing 497koz

• Stockpiled material, already mined, will be processed over the next 4.4 years, producing a further 133koz

Table 1:Key Study Metrics

• The Study focusses on the higher confidence Measured and Indicated Mineral Resource, which makes up 100% of the production target.

• The Proved Ore Reserve is 14.1Mt at 1.06g/t Au and the Probable Ore Reserve is 6.5Mt @ 0.72g/t Au. Total Ore Reserve ounces are 630koz at an average grade of 0.95g/t Au.

The production strategy involves prioritising the highest margin accessible material through the processing plant. Key points regarding the mill feed schedule include:

• Process plant commissioning and ramp-up occurs in year 1.

• Development of the Colosseum north and south open pits is staged to limit capital draw down while maintaining sufficient ore stocks to feed the mill.

• Metallurgical recovery averages 91%.

• Mining ceases at the end of year 6. A stockpile (11.3Mt) of low grade is processed through to the middle of year 11. Future extensional and regional exploration is expected to extend the period of mining, either via the open pits or an underground development.

Table 2: Colosseum Mine and Processing Production Schedule

• Cashflow analysis shows that while sensitive to fluctuations in both cost and gold price, the Project continues to deliver positive cash flows under conservative assumptions. This supports the positive financial outcome modelled under the base case scenario.

• For each $100/oz change in gold price there is a ~$55M change in pre-tax free cash flow.

This Study estimates the funding required to commence production.

To achieve the range of outcomes indicated in the Study, funding of $249M, plus a contingency of $25M, is required.

The Company has cash and equivalents of A$88M as at the date of this report. The Company is seeking to fund the development of Colosseum via a mixture of project financing and cash at hand.

Subsequent developments are assumed to be funded by positive cash flow generated from production.

Several pre-construction initiatives have commenced ahead of the Final Investment Decision (FID) for the Colosseum mine development.

An access road has been rehabilitated that connects the site with the Yates Well Road (sealed) and Interstate I-15.

A laydown and storage property has been optioned near the commencement of the access road on Yates Well Road. This property also includes two water bores, Colosseum #1 and #2, which will be used to supply water to the site.

The historical footings and foundations from the previous processing plant have been unearthed. Several of these areas have been assessed as being suitable for reuse in the Colosseum development.

An ‘as new' SAG and Ball Mill has been agreed to be acquired for the Colosseum Project. The mills were built in 2020 but have been stored in a bonded warehouse since. They will be transported to site in the coming months.

Dateline intends to enter into a power supply agreement for the re-establishment of grid power to the Colosseum mine site. An overhead transmission line will be re-established along the approved access corridor.

GR Engineering Services (GRES) has been awarded the Front-End Engineering and Design contract for the Colosseum processing plant. This work commenced in parallel with the BFS.

Dateline expects to appoint an Engineering, Procurement, Construction plus Management (EPC+M) contract in the coming month/s. To assist with the contracting strategy as well as site construction management, Dateline has appointed experienced project management consultants Alvarez & Marsal (A&M). A&M have commenced their scope and will fill out the Dateline team, offering a streamlined model to quickly upskill Dateline's internal execution capability.

Full details of the ASX Announcement and SK-1300 Technical Report Summary for the Colosseum Project is available on the Dateline Resources website at www.datelineresources.com.au

This press release has been authorized for release by the Board of Dateline Resources Limited.

For more information, please contact:

Stephen Baghdadi
Managing Director
+61 2 9375 2353

Andrew Rowell
Corporate & Investor Relations Manager
+61 400 466 226
a.rowell@dtraux.com
www.datelineresources.com.au

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About Dateline Resources Limited

Dateline Resources Limited (ASX:DTR,OTC:DTREF)(OTCQB:DTREF)(FSE:YE1) is an Australian company focused on mining and exploration in North America. The Company owns 100% of the Colosseum Gold-REE Project in California.

The Colosseum Gold Mine is located in the Walker Lane Trend in East San Bernardino County, California and is located 10km north of Mountain Pass rare earth mine. Drill testing the REE potential at Colosseum has commenced.

On 11 May 2026, Dateline announced that the BFS economics for the Colosseum Gold Project generated a pre-tax NPV₅ of US$785 million and a pre-tax IRR of 49.5% using a gold price of US$4,200/oz.

Dateline has also acquired the high-grade Argos Strontium Project, also located in San Bernadino County, California. Argos is reportedly the largest strontium deposit in the U.S. with previous celestite production grading 95%+ SrSO₄.

In March 2026, Dateline consolidated the Music Valley Heavy Rare Earth Project in Riverside and San Bernardino Counties, California. The region has known HREE mineralisation from USGS rock chip sampling, however it has not been subjected to modern exploration techniques.

Forward-Looking Statements

This announcement may contain "forward-looking statements" concerning Dateline Resources that are subject to risks and uncertainties. Generally, the words "will", "may", "should", "continue", "believes", "expects", "intends", "anticipates" or similar expressions identify forward-looking statements. These forward-looking statements involve risks and uncertainties that could cause actual results to differ materially from those expressed in the forward-looking statements. Many of these risks and uncertainties relate to factors that are beyond Dateline Resources' ability to control or estimate precisely, such as future market conditions, changes in regulatory environment and the behavior of other market participants. Dateline Resources cannot give any assurance that such forward-looking statements will prove to have been correct. The reader is cautioned not to place undue reliance on these forward-looking statements. Dateline Resources assumes no obligation and does not undertake any obligation to update or revise publicly any of the forward-looking statements set out herein, whether as a result of new information, future events or otherwise, except to the extent legally required.

Competent Person Statements

Sample preparation and any exploration information in this announcement is based upon work by Mr Graham Craig who is a Member of the Association of Professional Engineers and Geoscientists of Manitoba (APEGM). Mr Craig has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to quality as a Competent Person as defined in the 2012 Edition of the "Australasian Code for Reporting Exploration Results, Mineral Resources and Ore Reserves" (JORC Code). Mr Craig is a full time employee of Colosseum Rare Metals Inc. which is a wholly owned subsidiary of Dateline Resources Limited and consents to the inclusion in the report of the matters based on this information in the form and context in which it appears.

The data in this report that relates to Mineral Resource estimates for the Colosseum gold deposit is based on information evaluated by Mr Simon Tear who is a Member of the Australasian Institute of Mining and Metallurgy (AusIMM) and who has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the "JORC Code"). Mr Tear is a Director of H&S Consultants Pty Ltd and he consents to the inclusion in the report of the Mineral Resource Estimate in the form and context in which it appears.

The data in this report that relates to Ore Reserves estimates for the Colosseum gold deposit is based on work conducted or supervised by Mr John Wyche who is a Fellow and Chartered Professional of The Australasian Institute of Mining and Metallurgy (AusIMM) and who has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the "JORC Code"). Mr Wyche is a Director of Australian Mine Design and development Pty Ltd and he consents to the inclusion in the report of the Ore Reserves Estimate in the form and context in which it appears.

SOURCE: Dateline Resources Limited