shall not himself approach nor allow any other person to approach the shell during the interval of ten minutes after such attempt;

before approaching or allowing any other person to approach the shell shall disconnect the removable handle or key and the cable from the shot firing apparatus;

shall then examine the cable and connections for any defect;

if he leaves the working place while the shell remains there shall cause notice of the miss-fire to be given to the deputy in charge of the district and ensure that sufficient fences and danger notices are erected to notify the miss-fire to any person approaching the place.