S-2.1, r. 4 - Safety Code for the construction industry

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4.5.5. Before drilling any surface of a digging where blasting was performed, all bottoms of blastholes must be marked in either of the following manners:
(a)  by a circle in paint or crayon of a colour contrasting with the soil;
(b)  by inserting a stick into the hole.
O.C. 57-2015, s. 35.