OFFICIAL required. In response, Orica has undertaken a comprehensive research program to extend this understanding to longer durations, aiming to proactively manage risks associated with reactive ground in complex blasting applications enabled by wireless initiation systems. This paper describes the program findings that used isothermal testing, Accelerated Rate Calorimetry (ARC), and advanced thermal multiphysics modelling to understand chemical and thermal interactions between reactive ground and commercial explosives over extended sleep times. The findings offer critical insights into the mechanisms of heat generation and transfer in reactive environments and have led to strategies to unlock longer sleep times through the early detection and mitigation of reactive ground risks. This research supports the safe and sustainable implementation of innovative blasting technologies and contributes to the broader advancement of mining science. KEYWORDS Long Sleep Times, WebGenTM, Wireless Blasting, Reactive Ground. All information contained in this document is accurate and up-to-date as at the date of issue. Since Orica Group Companies and the Authors cannot anticipate or control the conditions under which this information and its products may be used, each user should review the information in the specific context of the intended application. To the maximum extent permitted by law, the Orica Group Companies and Authors will not be responsible for damages of any nature resulting from the use or reliance upon information in this document. No express or implied warranties are given, other than those implied mandatory by law. 1. Introduction Modern mining operations are increasingly adopting wireless initiation systems like WebGen™, that eliminate physical detonator connections and enable remote firing of blasts through rock, air, or water. This technology is applicable in open cut and underground mines. The uptake has been more rapid in underground operations because of the enhancements to mining safety and productivity by allowing multiple blasts to be preloaded and fired without requiring personnel to re-enter hazardous areas. However, with these benefits comes a new challenge: dramatically longer “sleep times” (the interval between starting to charge a shot and firing it) are now often necessary to implement safer and more productive sequenced blasts. Wired and non-electric initiation systems demand continuous personnel access to connect blastholes, so shorter sleep times are less of constraint. Wireless initiation enables novel mining methods that require explosives to sleep for months. Designing bulk explosives that will be stable for months in reactive ground is a critical science and engineering challenge to realise the benefits of these methods. Reactive ground refers to rock containing sulphide minerals (e.g. pyrite) that can undergo a spontaneous exothermic reaction upon contact with ammonium nitrate (AN), the oxidiser
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