The company will offer to shareholders of record on Friday, June 30, 2023, rights to purchase shares of the company. One right will be issued for every common share held. One right and one cent are required to purchase one common share. The expiry date for the rights offering is Sept. 5, 2023. As at June 14, 2023, the company had 204,534,458 shares issued and outstanding.

Effective at the opening, Thursday, June 29, 2023, the shares of the company will trade ex rights and the rights will commence trading at that time on a when-issued basis. The company is classified as a mining company.

Summary

Basis of offering:  For every share held, shareholders will receive one right exercisable for one share at one cent per share.

Record date:  June 30, 2023

Shares trade ex rights:  June 29, 2023

Rights called for trading:  June 29, 2023

Rights trade for cash:  Aug. 31, 2023 (Trading in the rights shall be for cash for the two trading days preceding the expiry date.)

Rights expire:  Sept. 5, 2023, at 2 p.m. Vancouver time

Trade dates:  Aug. 31, 2023, to settle Sept. 1, 2023; Sept. 1, 2023, to settle Sept. 5, 2023; Sept. 5, 2023, to settle Sept. 5, 2023

The rights will be halted at 12 p.m. Toronto time on Sept. 5, 2023, and will be delisted at the close of markets on the same day.

Trading symbol of rights:  MAS.RT

Cusip No. of rights:  57457A 11 3

Subscription agent and trustee:  Computershare Investor Services Inc.

Authorized jurisdictions:  all provinces and territories in Canada and in all jurisdictions outside Canada and the United States, excluding any jurisdiction that does not provide a prospectus exemption substantially similar to the exemption provided in Canada

For further details, please refer to the company's rights offering circular dated June 22, 2023, and news release dated June 22, 2023.

The company's rights offering circular has been filed with and accepted by the TSX Venture Exchange.