上分层 meaning in English

higher slice

Integrated control of gas in 13123 higher slice face
火铺矿13123上分层工作面瓦斯综合治理
Study on the directly transiting technology from the under slice mining face to the upper one
下分层直接过渡到上分层开采工艺研究
Analysis on danger of pressure bump when fully mechanized sublevel caving mining face passed through terminal mining line of top slicing seam
综放面过上分层终采线冲击地压危险性分析