MAGNESITA REFRATÁRIOS S.A.

TAXPAYER ID (CNPJ/MF) NO. 08.684.547/0001-65

PUBLICLY-HELD COMPANY

NOTICE TO THE MARKET

Sale of Relevant Shareholding Participation

São Paulo, December 6th, 2017 - Magnesita Refratários S.A. (Novo Mercado: MAGG3) ("Company"), announces that, in compliance with the Article 12, of the CVM Instruction no. 358/02, as amended, has received a correspondence on 11/09/2017 from its shareholder Alaska Investimentos Ltda, informing that after sales of the Company's shares, the investment funds under management of this institution now holds 2,535,530 shares issued by the Company, corresponding to 4.98% of the Company's capital.

Correspondence sent by the shareholder is attached (only in Portuguese).

Otavio Augusto Castro Lustosa Nogueira

CFO and Investor Relations Officer

Magnesita Refratários S.A.

Magnesita Refratários SA published this content on 06 December 2017 and is solely responsible for the information contained herein.
Distributed by Public, unedited and unaltered, on 06 December 2017 21:06:10 UTC.

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