1951 As shown above, the ability to safely extend sleep times in reactive ground has increased through innovations in testing and formulation. The new method moves from a paradigm of testing longer than the desired sleep time to one of calibration and prediction, grounded in scientific understanding of inhibitor chemistry. It is evident from the trends in Error! Reference source not found. that over decades increases in sleep time were achieved through progressively longer tests. The trend was inverted in 2025 based on the application of this work to provide a credible safety case for long sleep times using a standard test. 2. EXPERIMENTAL METHODS The research program was divided into two complementary streams: (1) a reactive ground testing stream to develop a new qualification test protocol for long sleep times, and (2) a product development stream to formulate an explosive with sufficient inhibition for 90-day sleep time in reactive ground. This paper focuses on the testing stream, which in turn involved several components: isothermal laboratory tests (based on the standard reactive ground test but modified for extended duration and variable inhibitor levels) and Accelerated Rate Calorimetry (ARC) experiments for kinetic analysis. Reactive Ground Isothermal Testing Isothermal refers to a test where the conditions are maintained at a set temperature, with a thermostat adding heat when the temperature drops below a set point and allowing heat to dissipate if the temperature exceeds a set point. The equipment required is simple and widely available, but the ability to maintain a set temperature is critical to ensuring reactions of interest are detected because heat is dissipated faster in the test than in blast holes. Figure 115 shows the reactive ground apparatus. The inset picture highlights the aluminium block, which provides good thermal conductivity and enables the test temperature to be maintained.
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