In this article the term "mine" includes the shafts, slopes, drifts or inclines connected with excavations penetrating clay seams or strata, which excavations are ventilated by one general air current or division thereof, and the surface structures or equipment connected therewith which contribute directly or indirectly to the underground mining of clay.
In this article the term "mine" includes the shafts, slopes, drifts or inclines connected with excavations penetrating clay seams or strata, which excavations are ventilated by one general air current or division thereof, and the surface structures or equipment connected therewith which contribute directly or indirectly to the underground mining of clay.
In this article the term "mine" includes the shafts, slopes, drifts or inclines connected with excavations penetrating clay seams or strata, which excavations are ventilated by one general air current or division thereof, and the surface structures or equipment connected therewith which contribute directly or indirectly to the underground mining of clay.
