What is a firebrick wall, or a stone, which forms the front of the hearth of a blast furnace. Dam plate (Blast Furnace), an iron plate in front of the dam, to strengthen it called?

dam — (Metal.) A firebrick wall, or a stone, which forms the front of the hearth of a blast furnace. Dam plate (Blast Furnace), an iron plate in front of the dam, to strengthen it. (Webster's 1913.)

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