High-Resolution Airborne Survey Completed at Music Valley HREE Project

Mapping and sampling underway to refine geological model

SAN BERNARDINO, CA / ACCESS Newswire / March 17, 2026 / Dateline Resources Limited (ASX:DTR)(OTCQB:DTREF)(FSE:YE1) (Dateline or the Company) is pleased to announce the completion of the geophysical survey covering the Music Valley Heavy Rare Earth Project (Music Valley), located in Riverside and San Bernardino Counties, California, USA.

The magnetic and radiometric survey included all of the 20,520 acres highlighted in the expanded Music Valley Project announcement (ASX Announcement 11 March 2026).

The helicopter-borne survey was undertaken by Precision GeoSurveys based in Reno, Nevada. The 2,172 line kilometre survey was flown on 50m spaced lines at a height of 30m using state of the art equipment.

Highlights

• 2,172 line kilometre survey completed:The helicopter-borne magnetic and radiometric survey has been completed over the expanded Music Valley HREE Project area, ahead of schedule.

• Low level = high resolution: The survey was completed on 50 metre line spacings at a flight height of 30 metres, which will generate a high-resolution dataset for processing and interpreting.

• Data Analysis Underway: The survey data has been provided to Mitre Geophysics for processing, inversions and analysis.

• Mapping and Sampling Underway: Dateline’s consulting REE and structural geology specialists are in the field, mapping and rock chip sampling across the expanded Music Valley HREE Project area.

Dateline’s Managing Director, Stephen Baghdadi, commented:

“Completion of the Music Valley airborne survey represents a step in Dateline’s systematic exploration of this emerging heavy rare earth district. The data will now be processed and integrated with field mapping and rock chip sampling to refine the Company’s geological model and guide the next phase of exploration.”

Figure 1: Music Valley HREE Project aerial geophysical survey area shown in red hatched area

Mapping and Field Sampling

The Company’s REE specialist, Tony Mariano Jr and Structural geologist Dr Russell Mason, have commenced field mapping and sampling at Music Valley. The primary target will be outcrops of Pinto Gneiss and contact zones with the surrounding rocks in the area.

Rock chip samples collected during this program will be dispatched for assaying, with results expected in 5-7 weeks.

Figure 2: Field and Pinto Gneiss outcrop photos from Music Valley

Additional Information

The Company notes that 252 of the 969 claims referenced in this announcement are the subject of proceedings currently before the Federal Court of Australia (Victoria Registry). Dateline will update the market in accordance with its continuous disclosure obligations.

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)(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. On 6 June 2024, the Company announced to the ASX that the Colosseum Gold mine has a JORC-2012 compliant Mineral Resource estimate of 27.1Mt @ 1.26g/t Au for 1.1Moz. Of the total Mineral Resource, 455koz @ 1.47/t Au (41%) are classified as Measured, 281koz @1.21g/t Au (26%) as Indicated and 364koz @ 1.10g/t Au (33%) as Inferred.

On 23 May 2025, Dateline announced that updated economics for the Colosseum Gold Project generated an NPV6.5 of US$550 million and an IRR of 61% using a gold price of US$2,900/oz.

The Colosseum is located less than 10km north of the Mountain Pass Rare Earth mine. Planning has commenced on drill testing the REE potential at Colosseum.

Dateline owns 100% of 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 mineralization 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 Statement

Sample preparation and any exploration information in this announcement is based upon work reviewed by Mr. Greg Hall who is a Chartered Professional of the Australasian Institute of Mining and Metallurgy (CP-IMM). Mr. Hall has sufficient experience that is relevant to the style of mineralization 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 Exploration Results, Mineral Resources and Ore Reserves” (JORC Code). Mr. Hall is a Non-Executive Director 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.

Company Confirmations

The Company confirms it is not aware of any new information or data that materially affects the information included in the announcements dated 23 October 2024 with regard to the Colosseum MRE and 23 May 2025 with regard to Colosseum Project Economics. Similarly, the Company confirms that all material assumptions and technical parameters underpinning the estimates and the forecast financial information referred to in those previous announcements continue to apply and have not materially changed.

SOURCE: Dateline Resources Limited

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