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A high-energy gas rock-breaking material and method suitable for shallow hole blasting has been proposed. The rock-breaking principle and law of high-energy gas were analyzed through laboratory rock-breaking experiments combined with CT scanning and three-dimensional reconstruction technology. The results showed that the specimen after the action of high-energy gas was broken evenly and the energy utilization rate was high. However, with the increase in the dosage, energy would be wasted and the rock would be over-crushed. According to the analysis of the deflagration pressure curve of high-energy powder, the action process of high-energy gas could be roughly divided into four stages: crack initiation, high-speed expansion, low-speed expansion, and pressure reduction. At the same time, the multi-level interaction mechanism of "gas expansion + detonation impact" between high-energy gas and rock mass was proposed. Finally, the superior rock-breaking effect of high-energy gas was verified through engineering application, which provides scientific guidance for the later scheme optimization. Highlights: Propose a high-energy gas rock breaking method applied in the field of shallow hole blasting, which is based on an energetic material. CT scanning technology can accurately describe the internal damage of rock mass. Revealed the multi-level interaction of "gas expansion + detonation impact" between high-energy gases and rock masses. [ABSTRACT FROM AUTHOR]

For explosion-proof and effective suppression measures in treating magnesium–aluminum alloy, it is of great importance to study the suppression of Mg–Al alloy dust explosions to prevent explosion disasters. The addition of inert solid substances to combustible dust is a measure aimed at preventing and reducing dust explosions. The explosion characteristics and flame propagation characteristics of Mg–Al alloy powder were studied using the Hartmann tube 20 L spherical explosion experimental system. The mechanism for removing sodium bicarbonate (NaHCO3) during the Mg–Al alloy powder explosion was further studied. The results show that the explosion pressure, the height of the deflagration flame, and the speed at which the flame propagates can be effectively reduced by increasing the percentage of NaHCO3. After the addition of 80% NaHCO3, the flame was suppressed, and the maximum explosion pressure decreased to less than 0.1 MPa, causing a 93% decrease in the maximum flame propagation speed. The process of suppressing NaHCO3 powder on magnesium aluminum alloy dust explosion is relatively complex, starting primarily with physical and chemical suppression. NaHCO3 realizes physical inhibition by reducing ambient temperature and oxygen concentration through the H2O and CO2 generated by decomposition. At the same time, through the cycle of NaO ↔ Na, the transformation from highly active oxygen to low active oxygen is realized. This reduces the activity of the explosive combustion response of Mg–Al alloy powder. At the same time, sodium ions can capture free radicals in explosive responses, reducing the number of free radicals in the reaction system and terminating the combustion reaction chain in advance. The research findings are of great importance for the safety of Mg–Al alloy production. [ABSTRACT FROM AUTHOR]