S-2.1, r. 14 - Regulation respecting occupational health and safety in mines

Section 462 Disposition versions

2012-09-01

462. Where explosive charges are fired by means of an electric power system:

(1)  the electrical circuit shall be:

(a)  isolated and not grounded;

(b)  used only for blasting;

(2)  the blasting switch shall be designed so that:

(a)  the switch mechanism automatically returns to the open position by gravity;

(b)  the conductors leading to the charges are automatically short-circuited when the switch is in the open position;

(c)  the energized switch terminals are enclosed in a fixed metal box;

(d)  the box in which the firing conductors and the short-circuiting device are placed is provided with a door and a closing device designed so that the door can be closed only when the switch is in the open position; this door shall be kept locked except at firing time; the key shall be accessible only to the person in charge of blasting;

(3)  a disconnecting device with overcurrent protection shall be installed between the source of power and the blasting switch; a horizontal protective gap against lightning of at least 1.5 m (4.9 ft) shall be provided between the disconnecting device and the blasting switch, and the gap may be closed only at the time of firing;

(4)  the voltage of the firing device shall not exceed 220 V.

O.C. 213-93, s. 462; O.C. 1326-95, s. 81.