21. Every Type I magazine and a mine accessible by ramps must be supervised in any one of the following ways:(a) by hourly visits to the magazine at irregular intervals, recorded by a punch clock;
(b) by closed-circuit television under constant scrutiny by a guard posted elsewhere on the premises;
(c) by an alarm system as defined in Schedule 9, connected to a guardhouse situated on the premises, and continuously manned by guards having the means of communication and transportation needed to take quick action in case of theft;
(d) by an alarm system connected to the nearest police station and continuously maintained in operation.