Clayton Valley Lithium Update

Vancouver, September 12, 2024 - Sienna Resources Inc. (TSXV: SIE) (OTC Pink: SNNAF) (FSE: A1XCQ0) ("Sienna" or the "Company") wishes to update the shareholders on some lithium developments that recently occurred in the Clayton Valley of Nevada. September 10, 2024 SLB (formerly Schlumberger) announced that "…SLB today announced it has proven its solution for sustainable lithium production at scale at its demonstration plant in Clayton Valley, Nevada, to accelerate responsibly-sourced lithium products to market…The proprietary integrated solution combines SLB's subsurface expertise with surface engineering of advanced technologies that include direct lithium extraction (DLE). It produces lithium 500 times faster than conventional methods while using only 10 percent of the land. Operating at approximately one tenth the size of a commercial-scale facility, the plant reached a verified recovery rate of 96% lithium from brine…In proving this solution at its pilot plant, SLB completed specific technical milestones allowing it to fully qualify under the earn-in agreement with Pure Energy Minerals Ltd. and, at its option, may acquire 100% ownership interest in the Clayton Valley Project" Sienna has property right inside of the Pure/SLB's Clayton Valley Project (see map) located in the deepest section of this basin. Sienna Resources' management cautions that past results or discoveries on properties in proximity to Sienna Resources may not necessarily be indicative of the presence of mineralization on the company's properties.

Sienna Resources Ownership Map

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Jason Gigliotti, President of Sienna Resources Inc. stated, "We would like to congratulate the SLB and Pure teams for many years of hard work finally coming to fruition. This is a watershed moment for the Clayton Valley itself, as this marks the true entrance of SLB into the lithium space. Sienna has been holding its Clayton Valley Deep Basin Lithium Projects for many years watching the developments on this project primarily, as Sienna shares the deepest part of this basin with SLB. SLB still has a road ahead, but this moment is clearly a turning point for development within this basin. We look forward to now moving this project much higher up in the Sienna project priority list."

Recently, Sienna announced (September 4, 2024) that it has significantly increased its acreage on the Stonesthrow Gold Project in Saskatchewan now consisting of approximately 31,718 contiguous acres prospective for gold directly bordering Ramp Metals Inc. Ramp announced (June 17, 2024) multiple zones of gold mineralization, including 73.55 grams per tonne gold and 19.50 grams per tonne silver. Ramp has just announced a strategic investment led by Eric Sprott. Sienna Resources' management cautions that past results or discoveries on properties in proximity to Sienna Resources may not necessarily be indicative of the presence of mineralization on the company's properties.

On May 23, 2024 Sienna acquired Case Lake West Cesium and Spodumene Pegmatite Project in the Larder Lake Mining division of Ontario, Canada, roughly 100 km north of Kirkland Lake, NE Ontario. This project consists of approximately 2,200 contiguous acres prospective for Cesium and Spodumene Pegmatites directly bordering Power Metals Corp's Case Lake cesium and pegmatite swarm discovery. On May 22, 2024 Power Metals announced "WORLD-CLASS CESIUM RESULTS UP TO 18.13% AT CASE LAKE." This was very exciting news regarding this growing cesium district. Sienna management cautions that past results or discoveries on properties in proximity to Sienna may not necessarily be indicative of the presence of mineralization on the company's properties.

About Sienna Resources Inc.

Sienna has significantly increased acreage of the "Stonesthrow Gold Project", consisting now of approximately 31,718 contiguous acres prospective for gold. Sienna has also recently acquired the "Case Lake West Cesium and Spodumene Pegmatite Project" in Larder Lake Mining division of Ontario, Canada roughly 100 km north of Kirkland Lake, NE Ontario. This project consists of approximately 2,200 contiguous acres prospective for Cesium and Spodumene Pegmatites. Sienna has also just acquired the 10,357 acre "Uranium Town Project" bordering Denison Mines Corp., the now 23,134 contiguous acre "Dragon Uranium Project" bordering Cameco Corp. and the 55,440 acre "Atomic Uranium Project" in the world renowned Athabasca Basin of Saskatchewan. Also, Sienna recently expanded the "Elko Lithium Project" in Elko County, Nevada. This project consists of approximately 1840 contiguous acres directly bordering Surge Battery Metals' "Nevada North Lithium Project" in Elko County, Nevada who announced the highest grade lithium deposit in the USA. Sienna is also one of the larger landholders in Clayton Valley Nevada. Sienna's Clayton Valley projects include the Blue Clay Lithium Project, the Silver Peak South Project, and the Clayton Valley Deep Basin Lithium Project. Clayton Valley is home to the only lithium production in North America, being Albemarle Corp's Silver Peak deposit. This project is also near Tesla Motors Inc.'s Gigafactory in Nevada. On March 18, 2021, Schlumberger New Energy Venture announced the development of a lithium extraction pilot plant through its new venture, NeoLith Energy in a strategic partnership with Pure Energy. The deployment of the pilot plant will be in Clayton Valley, Nevada, USA. The NeoLith Energy sustainable approach uses a differentiated direct lithium extraction (DLE) process to enable the production of high-purity, battery-grade lithium material while reducing the production time from over a year to weeks. Results from this pilot plant are expected in 2024 and could have a significant impact on the brine prospects within Clayton Valley Nevada as Sienna is located in the deepest section of this brine deposit.

Qualified Person:

Mr. Frank Bain, PGeo, a qualified person as defined by National Instrument 43-101 has reviewed and approved the scientific and technical disclosure contained within this news release.

"Jason Gigliotti"

President, Director
Sienna Resources Inc.

Statements in this news release that are not historical facts are forward-looking statements. Forward-looking statements are statements that are not historical, and consist primarily of projections - statements regarding future plans, expectations and developments. Words such as "expects", "intends", "plans", "may", "could", "potential", "should", "anticipates", "likely", "believes" and words of similar import tend to identify forward-looking statements. Forward-looking statements in this news release include uncertainty of exploration and development plans regarding the property; commodity price fluctuations; political or economic instability and regulatory changes; currency fluctuations, the state of the capital markets; uncertainty in the measurement of mineral reserves and resource estimates; the Company's ability to attract and retain qualified personnel and management; potential labour unrest; reclamation and closure requirements for mineral properties and the availability of capital to fund the Company's projects, as well as other risks and uncertainties identified under the heading "Risk Factors" in the Company's continuous disclosure documents filed on SEDAR. You are cautioned that the foregoing list is not exhaustive of all factors and assumptions which may have been used. The Company cannot assure you that actual events, performance or results will be consistent with these forward-looking statements, and management's assumptions may prove to be incorrect. These forward-looking statements reflect current expectations regarding future events and operating performance and speak only as of the date hereof and the Company does not assume any obligation to update forward-looking statements if circumstances or management's beliefs, expectations or opinions should change other than as required by applicable law. For the reasons set forth above, you should not place undue reliance on forward-looking statements.

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