An anonymous director reports

AVALON ADVANCED MATERIALS EXTENDS PROXY VOTING DEADLINE AHEAD OF SPECIAL MEETING

Avalon Advanced Materials Inc. has extended the deadline for shareholders to submit their votes (proxies or voting instruction forms) for the upcoming special meeting of shareholders.

• Previous voting deadline: Friday, Oct. 3, 2025, at 10 a.m. ET;
• New voting deadline: Monday, Oct. 6, 2025, at 4 p.m. ET;
• Special meeting date and time: Tuesday, Oct. 7, 2025, at 10 a.m. ET (location as set out in the meeting materials provided using notice and access and posted on the company's SEDAR+ profile on Sept. 8, 2025.

The extension is intended to give all shareholders additional time to review the meeting materials and participate in the vote.

Shareholders of record as of the record date set out in the meeting materials who have not yet voted are encouraged to do so as soon as possible using the instructions provided in their form of proxy or voting instruction form. Beneficial (non-registered) shareholders should follow the directions of their intermediary (bank, broker or other nominee). Previously submitted votes remain valid; shareholders who have already voted do not need to take any further action unless they wish to change their vote.

If you require assistance voting, please contact Avalon Investor Relations at ir@avalonam.com or 416-364-4938.

About Avalon Advanced materials Inc.

Avalon Advanced materials is a Canadian critical minerals company advancing the supply of materials essential for Canada's future. The company is focused on developing strategic assets that support secure, domestic supply chains and long-term economic growth. Avalon is focused on vertically integrating the Ontario lithium supply chain through the development of Lake Superior Lithium Inc., Ontario's first midstream lithium hydroxide processing facility, located in Thunder Bay. This facility will serve as a vital link between Northern Ontario's lithium resources and the growing EV (electric vehicle) battery manufacturing base in Southern Ontario and North America. Through a joint venture with SCR-Sibelco NV, Avalon is advancing the Separation Rapids lithium project near Kenora, Ont., as well as continuing exploration at its Snowbank lithium and Lilypad lithium-cesium deposits. The company is also advancing the Nechalacho rare-earths and zirconium project in the Northwest Territories. This deposit contains all light and heavy rare-earth elements, as well as yttrium, zirconium, tantalum and niobium -- critical minerals used in advanced technologies across the communications, defence, clean tech and energy sectors.

We seek Safe Harbor.