8.11.8. When tunnels cover a distance of more than 150 m from the base of a shaft, a telephone system shall be installed with extensions:(a) at the surface;
(b) at the base of the shaft; and
(c) at a maximum distance of 75 m from the face.
Telephone outlets shall be installed at intervals of 150 m along the tunnel.
R.R.Q., 1981, c. S-2.1, r. 6, s. 8.11.8.