mining shaft skip

Mine shaft ore skip and cage changing device Download PDF Info Publication number US1949399A. US1949399A US672481A US67248133A US1949399A US 1949399 A US1949399 A US 1949399A US 672481 A US672481 A US 672481A US 67248133 A US67248133 A US 67248133A US 1949399 A US1949399 A US 1949399A Authority US United States Prior art keywords carrier cage

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