Hi, firstly it is not Czechoslovenia, but Czechoslovakia

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Kutná Hora commemorative gros, which was minted in the State Mint Kremnica for the exhibition 700 years of Czechoslovak mining, held in May 1949 in Kutná Hora, where coins were sold only to visitors to this exhibition for the amount of 100, - Kčs, Ag 0.987, 27 mm (4 g), hallmark Kremnice and hallmark of fineness 987.