opencast
adjective UK uk/ˈəʊ.pən.kɑːst/ us/ˈoʊ.pən.kæst/ (US open-cut, open-pit)
（尤指煤）露天的，露天开采的
used to describe a place where minerals, especially coal, are taken from the surface of the ground rather than from passages dug under it, or relating to this way of getting minerals
opencast mine/mining 露天矿场／采矿