波尔特·马洪矿是一个年产超过一百万吨的地采石膏矿。位于巴黎西面30公里的塞纳河畔的沃克斯(伊夫林)。采用分段崩落法,分层高度为6米。机械化程度很高。全员(包括工头)工效达到50吨以上。石膏层比塞纳河海拔高80米,有20—80米厚的覆盖层。地表看不到露头—即被水溶蚀的石膏。然而在地表若干米以下有明显的水平露 The Port Mahon Mine is a gypsum mine with an annual output of more than one million tons. Vaux-sur-Seine, 30 km west of Paris. Using subsided caving method, the stratification height is 6 meters. High degree of mechanization. Full (including foreman) Ergonomics reached 50 tons and above. Gypsum layer Seine 80 meters above sea level, 20-80 meters thick cover. The surface can not be seen outcrops - plaster that is water-corrosive. However there is a noticeable level of exposure below a few meters on the surface