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SIEN.V ·

The news release was disseminated through News File and Stockwatch.

Corporate Updates

51-102F3

MATERIAL CHANGE REPORT

Item 1 Name and Address of Company

Sienna Resources Inc. (the “Company”)

Suite 2905 – 700 West Georgia Street

Vancouver, B.C. V7Y 1C6

Item 2 Date of Material Change

August 18 & 31, 2021

Item 3 News Release

The news release was disseminated through News File and Stockwatch.

Item 4 Summary of Material Change

On August 18, 2021, the Company announced that a second phase of surface exploration work had

started on the Marathon North Platinum-Palladium Property in Northern Ontario. On August 31,

2021, the Company announced the results from its recently executed drill program at its 100% owned

Bleka Gold Project (the “Project”) in Norway. Seven drill holes were completed at the Project for a total

of 1,474 meters.

Item 5 Full Description of Material Change

5.1 Full Description of Material Change

See attached news release.

5.2 Disclosure for Restructuring Transactions

N/A

Item 6 Reliance on subsection 7.1(2) or (3) of National Instrument 51-102

N/A

Item 7 Omitted Information

None

Item 8 Executive Officer

Jason Gigliotti, President, Corporate Secretary, Tel: 604-646-6900

Item 9 Date of Report

August 31, 2021

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Sienna Resources Inc.

Suite 2905-700 West Georgia Street

Vancouver, BC V7Y 1C6

SIENNA COMMENCES PHASE 2 SURFACE EXPLORATION PROGRAM, MARATHON

NORTH PLATINUM-PALLADIUM PROJECT, ONTARIO

Vancouver, B.C., August 18, 2021, Sienna Resources Inc. (“Sienna” or the “Company”) (SIE—

TSX.v, SNNAF—USA, A1XCQ0--Germany) is pleased to announce that a second phase of surface

exploration work has begun on their Marathon North Platinum-Palladium Property (the “Property”) in

Northern Ontario (see Figure 1), directly bordering Generation Mining Ltd.’s Marathon palladium

project. This Phase 2 program, which will include geological mapping, prospecting, and sampling,

follows up on the results from the first phase of surface exploration compl eted in late 2020 (see

Company news release dated October 27, 2020) which identified a number of prospective locations with

promising geology and minor sulphide mineralization.

Jason Gigliotti, President of Sienna Resources Inc., stated, “We are very pleased to now be underway on

the Marathon North Platinum-Palladium Property in Ontario. This area is a world-class PGM region,

and we are looking forward to what the next phase of operations will bring. We are also awaiting our

drill results from the Bleka Gold Project in Norway and are now underway with our exploration program

at our Kuusamo PGE Project in Finland. Also, a very significant development occurred yesterday in the

Clayton Valley of Nevada, where Pure Energy Minerals Ltd. partner Schlumberger New Energy has

received approval from the Bureau of Land Management (BLM) for a plan of operations covering the

construction and operation of a pilot plant at Pure Energy's Clayton Valley, Nevada, lithium brine

project. This project directly borders Sienna, and in fact Sienna’s property lies directly inside of the

Pure Energy land and is located in the deepest part of this basin. Clearly there are multiple projects that

give Sienna shareholders potential for growth in the near and long term.”

- 3 -

Figure 1. General geology of the Coldwell Intrusive Complex and surrounding area, with the location of

Sienna’s four mining claim groups. The current exploration program will be targeting the westernmost

claim group as a priority area, west of the Geordie Lake deposit.

- 4 -

Sienna is one of the largest landholders within the Coldwell complex area, which is the largest alkaline

intrusive complex in North America and hosts the Marathon PGM Deposit. According to Generation

Mining’s website, the Marathon PGM Deposit is one of the largest undeveloped platinum group metal

mineral resources in North America, hosting several platinum group metal (PGM) and copper deposits,

including the 8.7 million palladium-equivalent (PdEq) ounces in the Measured and Indicated categories

and an additional 915,000 PdEq ounces in the Inferred category. On 7 January 2020, Generation Mining

released a preliminary economic assessment (PEA) giving Marathon an after -tax net present value

(NPV) of $871 million and an after tax payback of 2.5 years. Management cautions that past results or

discoveries on properties in proximity to Sienna may not necessarily be indicative to the presence of

mineralization on the Company’s properties.

In other relevant news from the Clayton Valley in Nevada announced August 17, 2021, “Pure Energy

Minerals Ltd. partner Schlumberger New Energy has received approval from the Bureau of Land

Management (BLM) for a plan of operations covering the construction and operation of a pilot plant at

Pure Energy's Clayton Valley, Nevada, lithium brine project. Schlumberger, Pure Energy's partner and

operator of the Clayton Valley Project, has also received permit approval for the associated reclamation

plan from the Nevada Division of Environmental Protection, Bureau of Mining Regulation and

Reclamation. Construction and operation of the pilot plant are planned to occur at Pure Energy's Clayton

Valley property located 40 miles southwest of Tonopah in Esmeralda County, Nevada, as approved by

the BLM and Nevada authorities. In March 2021, Schlumberger New Energy announced its plans to

develop a lithium extraction pilot plant at the Clayton Valley Project through its wholly owned

subsidiary, NeoLith Energy (see Pure Energy news release of March 20, 2021).” Sienna has a br ine

project that is completely surrounded and located in the deepest section of Pure’s property (see Clayton

Valley map below). Management cautions that past results or discoveries on properties in proximity to

Sienna may not necessarily be indicative to the presence of mineralization on the Company’s properties.

- 5 -

About Sienna Resources Inc.

- 6 -

Sienna Resources is focused on exploring for and developing high-grade deposits in politically stable,

environmentally responsible and ethical mining jurisdictions. Sienna is partnered with a New York

Stock Exchange-listed mining company on two separate projects in Scandinavia including the past-

producing Bleka and Vekselmyr orogenic gold projects in southern Norway which are both greenstone-

hosted gold systems, and the Kuusamo Platinum Group Element (PGE) Project in Finland, directly

bordering the LK Project being advanced by Palladium One Mining Inc. In North America, Sienna's

projects include the Marathon North Platinum-Palladium Property in Northern Ontario, directly

bordering Generation Mining Ltd.'s 8.7 million PdEq ounce Marathon deposit. Sienna also has the

Clayton Valley Deep Basin Lithium Project in Clayton Valley, Nevada, home to the only lithium brine

basin in production in North America, in the direct vicinity of Albemarle Corp.'s Silver Peak deposit and

Tesla Motors Inc.'s Gigafactory. Management cautions that past results, discoveries or mineralization

described on properties in proximity to Sienna may not necessarily be indicative of the presence of

mineralization on the Company's properties.

The technical content of this news release was approved by Dr. Scott Jobin-Bevans (P.Geo.), a

consulting geologist and qualified person as defined by National Instrument 43-101.

If you would like to be added to Sienna’s email list please email [email protected] for

information or join our twitter account at @SiennaResources.

Contact Information

Tel: 1.604.646.6900

Fax: 1.604.689.1733

www.siennaresources.com

[email protected]

“Jason Gigliotti”

President, Director

Sienna Resources Inc.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in

the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this

press release.

- 7 -

Sienna Resources Inc.

Suite 2905-700 West Georgia Street

Vancouver, BC V7Y 1C6

Sienna Announces Drill Results on The Bleka Gold Project in Norway

Vancouver, B.C., August 31, 2021, Sienna Resources Inc. (“Sienna” or the “Company”) (SIE —TSX.v,

SNNAF—USA, A1XCQ0–Germany) is pleased to announce results from its recently executed drill program at its

100% owned Bleka Gold Project (the “Project”) in Norway. Seven drill holes were completed at the Project for a

total of 1,474 meters. Six drillholes were designed to test extensions of the mineralized “Main Vein” at depth and

along strike from the historic Bleka Mine (see Figure 1). A seventh hole targeted an outcropping quartz vein

swarm located approximately one kilometer from the historic Bleka Mine (the Espelid target). Sienna’s maiden

drill program confirmed extensions of the vein systems along strike and at depth, and intersected multiple quartz

veins with pervasive quartz-albite alteration halos and elevated gold and copper values.

The historic Bleka vein was discovered in 1880 and was mined intermittently until 1940 and shows characteristics

typical of greenstone-hosted vein deposits. Sienna’s drilling intersected the “Main Vein” in each of six drill holes,

including intersections 147 meters below the historic workings (as seen in DH-BLE-01) and 40 meters further

along strike of the workings (as seen in DH-BLE-05). Notable intercepts include 1.7 g/t Au over 0.8 meters at a

depth of 122.1 meters in DH-BLE 05, 0.21 g/t Au with 0.30% Cu over 0.15 meters at 60 meters depth in DH-

BLE-02, and 0.25 g/t Au with 0.45% Cu over 0.28 meters at 24.1 meters depth in DH-BLE-031.

Gold mineralization at Bleka is hosted by muti-stage quartz veins with locally intense albite-carbonate alteration

of wall rocks. Gold is associated with bismuthinite, chalcopyrite and pyrite according to historic accounts from

mining activities and as seen in Sienna’s drill holes. Although it had been mined for many decades, little to no

recent exploration has been conducted on the Project area. A drill program had been planned for the Project in the

late 1990’s, but was not executed, and no other records of exploration drilling have been located by the Company.

1 Insufficient drilling and modelling has been completed to definitively determine the true thicknesses of the intercepts. The

reported intercepts are as seen and measured in drill core and are drill intercept lengths.

- 8 -

To its knowledge, Sienna is the first company to drill the Project in the past 40-50 years. The company is now

formulating a plan for the next phase of operations on the Bleka project.

Notes on sampling methods.

A total of 151 samples were cut at the ALS laboratory in Mala, Sweden where the samples were crushed and

pulverized before they were shipped to be analyzed at the ALS laboratory in Ireland. The samples were analyzed

with a 4-Acid digestion and multi-element mass spectrometer analysis. Gold was determined by fire -assay

methods. Sampling was done in accordance with NI 43-101 protocols. Regular duplicate samples are taken and

regular check samples such as blank material as well as certified reference material is inserted into the samples

stream.

Figure 1: Location of drill holes and intercepts in the vicinity of the historic Bleka Mine

.

About Sienna Resources Inc.

Sienna Resources is focused on exploring for and developing high-grade deposits in politically stable,

environmentally responsible and ethical mining jurisdictions. Sienna is partnered with a New York

Stock Exchange-listed mining company on two separate projects in Scandinavia including the past-

producing Bleka and Vekselmyr orogenic gold projects in southern Norway which are both greenstone-

hosted gold systems, and the Kuusamo platinum group elements (PGE) project in Fin land directly

bordering the LK Project being advanced by Palladium One Mining Inc. In North America, Sienna's