7 | P a g e Class 1 Location Assessment Willows Road - Surface Magazine, WUG - Waihi North Project . ‘hazardous fragments/ m2’). The determination of evacuation zones and a Trigger Action Response Plan (TARP) form part of the site’s operational Emergency Response Plan (ERP). Threshold overpressure management is effected in one of two ways. That is, either by total NEQ stored, or by altering the distance of the storage location in relation to infrastructure, buildings or personnel. Controlled zone offset requirements have been derived from calculations considering ‘ TNT Equivalence’ as the donor explosive, referencing ‘International Ammunition Technical Guideline (IATG 1.80) - Formulae for Ammunition Management’, Part 6.2.1, Table 9a, Kingery and Bulmash - Polynomial for Incident Pressure (Hemi-Spherical Surface). and ‘ Part 5 Table 1: Hopkinson-Cranz Scaling Law’ Refer to ‘ TNT Equivalence’ in ‘Terms and Definitions’. Controlled zone offset requirements have been based on the greatest offset distance in relation to the stored NEQ specific to each individual magazine within the class 1 storage facility A total controlled zone contour has been developed. This is an aggregate of all of the controlled zones associated with each individual magazine unit. Where I.E magazines are positioned within minimum IMD for ‘other explosives storage’ as per ‘ Table 3.2.3.2 of AS 2187.1 ’, the aggregate NEQ for relevant H.E and I.E magazines is used to calculate the controlled zone area. Whilst the I.E magazine positioning may be altered to suit operational needs, the offset distance between I.E and H.E magazines is to be maintained in accordance with ‘ Table 3.2.3.1 ’ of ‘ AS 2187.1’ . 4.3. Controlled Zone Considerations in Relation to Regulatory Thresholds The paragraphs below outline the regulatory definitions for each of the controlled zones and how the proposed class 1 storage location will achieve the necessary compliance. Controlled zone definition – 24 kPa r 9.27(4)(a) – A PCBU with management or control of a hazardous substance location that is used solely for securing and holding a class 1 substance must limit the quantities of any class 1 substance at the location to ensure that, in the event of an unintended initiation, - i. the interior of any proximate building where a class 1 substance is manufactured would not be subject to a blast overpressure of more than 24 kPa. Formula for minimum offset distance in accordance with the above criteria - D = 7.2Q1/3 Proposed class 1 site - Compliance summary. • This is currently not applicable as the manufacture of class 1 substances on site is not being considered at present. • Where manufacture may be considered using A.N (Ammonium Nitrate), ‘ Table 3.2.3.2’ , Associated Works’ of ‘ AS 2187.1’, ‘ applies in relation to minimum offsets to ‘A.N storage. • Controlled zone offsets shall be considered if manufacture does occur. Controlled zone definition – 13 kPa r 9.27(2)(a)(i) - public traffic routes of low density and places where people may occasionally be present in numbers up to 200 persons on average in any 24-hour period are not subject to any of the following: i. a blast overpressure more than 13 kPa. Formula for minimum offset distance in accordance with the above criteria – D = 11.2Q1/3
RkJQdWJsaXNoZXIy MjE2NDg3