Avalon Reports Drill Results from 2022-2023 Exploration Program at Separation Rapids

Toronto, June 1, 2023 - Avalon Advanced Materials Inc. (TSX: AVL) (OTCQX: AVLNF) ("Avalon" or the "Company") is pleased to announce final assays from the 2022-2023 drilling program at the Company's flagship Separation Rapids Lithium Project, confirming potential to significantly expand its lithium resource at depth. New significant intercepts shown below are from three of the four final drill holes.

• SR23-85: 1.56% Li₂O over 47.71 metres ("m")
• SR23-91: 1.06% Li₂O over 10.38m and 1.66% Li₂O over 7.01m and 1.36% Li₂O over 10.61m
• SR23-92: 1.47% Li₂O over 3.42m and 1.14% Li₂O over 4.35m and 1.49% Li₂O over 4.52m

The assays for drill hole SR23-93 (the fourth hole) have confirmed the petalite mineralization to 566-metre depth increasing the potential depth of the deposit by 80%. The drilling has also confirmed that the deposit is open to the east and west, and to depth, over a 300-strike length, with similar grades to the current mineral resource estimate, supporting a conceptual target to double the size of the deposit through future drilling.

"These drill results truly demonstrate what our team has always believed - the resource at Separation Rapids is potentially much larger than what is currently understood," commented Rickardo Welyhorsky, Chief Operating Officer at Avalon. "I am extremely excited to begin the next drilling program to reveal its true potential."

Drilling Program Final Assay Details

The 2022-2023 drill program consisted of 12 drill holes on the existing resource and one vertical drill hole on the centre of the deposit; all 13 holes totalled 4,179m and was designed to examine the potential to expand mineralization to the east and west as well as the depth extent.

Hole SR23-85 (see Figure 1) was one of six targeting either gaps in existing drilling (for 85) or below the current mineral resource estimate, with hole SR23-85 intercepting 1.56% Li₂O over 47.7m (estimated true width). As a result, all six holes (SR23-81 to SR23-86) confirm that the deposit is open to depth. All drill holes will be used to update the existing mineral resource estimate, which is currently underway.

Drill hole SR23-93 was drilled vertically to test the depth extent of the deposit (see Figure 2). This hole was terminated at 570m due to weather constraint and the start of early spring breakup. SR23-93 assays returned 1.51% Li₂O over 565m (drilled width) confirming the previous report of visual petalite mineralization to depth. This extends the depth of the deposit by 249m from the previously reported deepest intercept at 315m (drilled in 2017) below surface. The grade of the lower half of hole SR23-93 returned 1.48% Li₂O over 244.45m (from 321.6m to 566.10m) (see Table 1), which indicates that the mineralization continues at a virtually identical grade to the current mineral resource estimate.

The two holes (SR23-91 and SR23-92) that were drilled in a gap on the western part of the deposit have confirmed the extension and openness of the deposit to the west with intercepts of cumulative about 27m (estimated true width) in hole SR23-91 and cumulative 12 metres in hole SR23-92. They have also, similar to hole SR23-85, potentially improved and expanded the mineralized area.

All drill hole data has been brought into Avalon's database and resource block model in order to develop an independent updated resource estimate for the deposit.

"As a consequence of our refreshed strategic plan, we are delivering on key milestones and accelerating developments at Separation Rapids," noted Zeeshan Syed, President of Avalon. "Ontario continues to be well positioned as an international economic hub within the critical minerals value chain and Avalon is poised for growth to help support that important mandate."

Future Drilling at Separation Rapids

The recent drill program indicating the significant resource expansion potential is an encouragement for very significant future drilling program in order to both increase the inferred resources and upgrade inferred and indicated resources to indicated and measured categories. Such a program may be between 10,000m and 30,000m. The results of the recent program suggest a conceptual exploration target of doubling the existing resource estimate at similar lithium grades. This may be between 15 and 20 million tonnes at 1.2 to 1.6% Li₂O. At present there is insufficient drilling below the recent holes SR23-81 to SR23-92 to delineate a resource and it is uncertain that a deeper resource will be delineated.

This news release was reviewed by the Dr. Bill Mercer, P. Geo. (ON). Dr. Mercer is a qualified person for the purposes of National Instrument 43-101, who has reviewed and approved the technical information included in this news release.

About Avalon Advanced Materials Inc.

Avalon Advanced Materials Inc. is a Canadian mineral development company specializing in niche market metals and minerals with growing demand in new technology. The Company has three advanced stage projects, all 100%-owned, providing investors with exposure to lithium, tin and indium, as well as rare earth elements, tantalum, niobium, and zirconium. Avalon is currently focusing on its Separation Rapids Lithium Project, Kenora, ON and its East Kemptville Tin-Indium Project, Yarmouth, NS. Social responsibility and environmental stewardship are corporate cornerstones.

For questions and feedback, please e-mail the Company at ir@AvalonAM.com, or phone Zeeshan Syed, President at 416-364-4938.

This news release contains "forward-looking statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995 and applicable Canadian securities legislation. Forward-looking statements include, but are not limited to, that there is potential to significantly expand its lithium resource at depth, that there is support for a conceptual target to double the size of the deposit through future drilling, that the resource at Separation Rapids has the potentially to be much larger than what is currently understood, that certain drill holes will be used to update the existing mineral resource estimate, that the recent drill program indicating the significant resource expansion potential is an encouragement for very significant future drilling program in order to both increase the inferred resources and upgrade inferred and indicated resources to indicated and measured categories, that such a program may be between 10,000 to 30,000 metres, that the results of the recent program suggest a conceptual exploration target of doubling the existing resource estimate at similar lithium grades, that this may be between 15 and 20 million tonnes at 1.2 to 1.6% Li₂O. Generally, these forward-looking statements can be identified by the use of forward-looking terminology such as "potential", "scheduled", "anticipates", "continues", "expects" or "does not expect", "is expected", "scheduled", "targeted", "planned", or "believes", or variations of such words and phrases or state that certain actions, events or results "may", "could", "would", "might" or "will be" or "will not be" taken, reached or result, "will occur" or "be achieved". Forward-looking statements are subject to known and unknown risks, uncertainties and other factors that may cause the actual results, level of activity, performance or achievements of Avalon to be materially different from those expressed or implied by such forward-looking statements. Forward-looking statements are based on assumptions management believes to be reasonable at the time such statements are made. Although Avalon has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking statements, there may be other factors that cause results not to be as anticipated, estimated or intended. Factors that may cause actual results to differ materially from expected results described in forward-looking statements include, but are not limited to market conditions, and the possibility of cost overruns or unanticipated costs and expenses as well as those risk factors set out in the Company's current Annual Information Form, Management's Discussion and Analysis and other disclosure documents available under the Company's profile at www.SEDAR.com. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Such forward-looking statements have been provided for the purpose of assisting investors in understanding the Company's plans and objectives and may not be appropriate for other purposes. Accordingly, readers should not place undue reliance on forward-looking statements. Avalon does not undertake to update any forward-looking statements that are contained herein, except in accordance with applicable securities laws.

Figure 1: North-South Drill Section, Separation Rapids Lithium Deposit

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Figure 2: West-East Long Section, Separation Rapids Lithium Deposit

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Table 1: Significant drill intersections

Notes to TABLE 1:

1. True widths are estimated assuming the mineralized zones are vertical and true width is horizontal. The near vertical nature is clearly apparent in drill sections. "NA" indicates for the vertical hole that the mineralization width is not known.
2. For interval calculations a cutoff grade of 0.50% Li2O was utilized which is similar to that used in previous resource estimates. Mineralized intervals with overall grades considerably below 1% Li2O are not quoted.
3. All drill core was split by Avalon staff on site near Kenora and shipped to ALS Global in Thunder Bay for preparation and on to ALS Vancouver for analysis by methods ME-MS81, ICP-06, and ME-4ACD81for multielement analysis including Li, Ta, Cs and Rb.
4. Some drill core samples had lithium values overlimits for the initial analytical method (>10.000ppm Li) and were reanalysed utilizing ALS method ME-ICP82b. As a result, some intervals increased in grade from those announced in News Release 23-04.
5. Avalon inserted company certified lithium standards and blanks into the sample stream for QAQC purposes. The results of the Avalon and laboratory standards and blanks were reviewed for acceptance by the QP, Dr. Bill Mercer, P. Geo. (ON), qualified person for the purposes of National Instrument 43-101, prior to accepting the laboratory results.
6. Lithium (Li) analyses in ppm were converted to Li₂O values by multiplying by 2.1527.
7. The drill program was supervised in the field by J.C.Pedersen (P.Geo) and A. Meek (P.Geo).

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