Waihi Surface Explosives Principal Management Plan Approved by: General Manager Approval Date: 15/10/2017 Next Review: Archived OceanaGold Waihi Doc ID: WAI-350-PLN-003 Page 18 of 31 Noise and vibration Geological features Adjacent underground or surface workings For more information refer to the procedure for blast clearance; see Appendix I for document details. 6.5.2 Fly Rock Management Fly rock is defined as the rock propelled from the blast area by force of an explosion. The primary factors for fly rock are: Insufficient burden or stemming Improper blast hole layout, loading, excessive powder factor Anomaly in the geology and rock structure Inadequate time delay Every effort is made to minimise the risk of fly rock to the operation the community which may include but not limited to: Training of all personnel involved in the blasting process Monitoring and reporting of any high risk holes Use of water to reduce the explosive power in high risk holes Use of blast mats or stemming bags as necessary to contain possible fly rock Adherence to blast designs 6.5.3 Firing Procedure Prior to firing an explosive, the Approved Handler must take all necessary precautions to ensure that: All personnel and equipment within or approaching the blast exclusion zone are withdrawn to a safe distance All means of approach to the blast exclusion zone are guarded against entry by any person or traffic by appropriate signage warning of blasting operations and physical guards (or other effective devices) to prevent entry and provide warning The Approved Handler can then: Cause a series of three short audible signals to be sounded to indicate imminent blasting Cause the blast to be fired within 90 seconds after the three audible signals are sounded Cause the area to be checked to ensure all dust and toxic gasses had dispersed and in all other respects the area is safe for return Cause two short audible signals to be sounded to indicate the all clear NOTE: the Approved Handler must not use a signal which is capable of being mistaken for a motor horn as a warning signal. For more information refer to the procedure for blast clearance; see Appendix I for document details. 6.6 Cancelled and Sleeping Blasts If a scheduled blast using electronic detonators is cancelled and has already been tied in, the shot will not be untied. In this situation delineation and signage will be reviewed and reinstated as necessary and the blast will be treated as a sleeping blast. Generally the tie in of the shot and the incorporation of the delays will be left until the last possible moment. Sleeping of blasts shall preferably be only from one day to the next. All blast holes must be stemmed correctly. The blast must be delineated with witches hats, blasting in progress signs and red flashing lights. For more information refer to the procedure for sleeping pre-loaded blast patterns; see Appendix I for document details.
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