sec.325Types of seals for mine entrances and other parts of mine

### sec.325 Types of seals for mine entrances and other parts of mine The underground mine manager for an underground mine must ensure each seal installed at an entrance from the surface to the underground mine is a type E seal. The underground mine manager must ensure each seal installed in any other part of the mine is— if the level of naturally occurring flammable gas at the mine is insufficient to reach the lower explosive limit for the gas under any circumstances—a type B seal; or if persons remain underground when an explosive atmosphere exists and there is a possibility of spontaneous combustion or incendive spark or other ignition source—a type D seal; or otherwise—a type C seal. Nothing in this section prevents a type E seal from also being designed for pressure relief for an overpressure of more than 70kPa. In this section— type B seal means a ventilation control device capable of withstanding an overpressure of 35kPa. type C seal means a ventilation control device capable of withstanding an overpressure of 140kPa. type D seal means a ventilation control device capable of withstanding an overpressure of 345kPa. type E seal means a ventilation control device capable of withstanding an overpressure of 70kPa. (sec.325-ssec.1) The underground mine manager for an underground mine must ensure each seal installed at an entrance from the surface to the underground mine is a type E seal. (sec.325-ssec.2) The underground mine manager must ensure each seal installed in any other part of the mine is— if the level of naturally occurring flammable gas at the mine is insufficient to reach the lower explosive limit for the gas under any circumstances—a type B seal; or if persons remain underground when an explosive atmosphere exists and there is a possibility of spontaneous combustion or incendive spark or other ignition source—a type D seal; or otherwise—a type C seal. (sec.325-ssec.3) Nothing in this section prevents a type E seal from also being designed for pressure relief for an overpressure of more than 70kPa. (sec.325-ssec.4) In this section— type B seal means a ventilation control device capable of withstanding an overpressure of 35kPa. type C seal means a ventilation control device capable of withstanding an overpressure of 140kPa. type D seal means a ventilation control device capable of withstanding an overpressure of 345kPa. type E seal means a ventilation control device capable of withstanding an overpressure of 70kPa. - (a) if the level of naturally occurring flammable gas at the mine is insufficient to reach the lower explosive limit for the gas under any circumstances—a type B seal; or - (b) if persons remain underground when an explosive atmosphere exists and there is a possibility of spontaneous combustion or incendive spark or other ignition source—a type D seal; or - (c) otherwise—a type C seal.