Gas hazard of explosives used in the mining industry

Reducing emissions of hazardous pollutants that have a negative impact on the environment and human health has been approved as one of the strategic objectives of Russia's development. More than 90% of minerals in mined using blast energy. Despite an increase in the share of non-explosive component mixtures used in mining, blasting still poses a hazard to miners as the gaseous detonation products are potentially dangerous. The composition of blast gaseous products is extremely important in underground blasting because air exchange is difficult under these conditions and the blast products can contaminate the atmosphere of underground excavations, causing illness or poisoning of miners. Currently, there are no uniform requirements for obtaining information on the amount of gaseous blast products that would be hazardous to the human organism. Available documents do not contain information on the permissible amounts of toxic oxides per 1 kg of explosive detonated. The article compares the results of studying gas toxic hazard of industrial explosives obtained by different methods and based on different criteria.

Air-blast and ground shockwave parameters, shallow underground blasting, on the ground and buried shallow underground blast-resistant shelters: A review

Weak political systems and poor governance in certain developing countries are found to have a war-like environment where structures are being targeted by blasts and bombs. Industrial blasts due to frail know-how and mishandlings are also quite common. Recent accidental explosions like that occurred at the Beirut Port, Lebanon (August 2020); ammunition depot in the outskirt of the Ryazan City of Russia (November 2020) are of concern for the safety of adjacent building infrastructure and their users. Such intense loading events cause damage to certain elements of a structure which may result in disproportionate or progressive collapse. It necessitates a clear understanding of the phenomenon of the blast and extreme loads induced out of it, and response of the target structure under such loadings. In this study, the state of research on air-blast and ground shockwave parameters, shallow underground blasting, and on the ground and buried shallow blast-resistant shelters are presented. The phenomenon of the self-Mach-reflection of the explosion, loading parameters and empirical blast models available in the open literature followed by the damage criteria for the buildings subjected to the underground blasting and available peak particle velocity (PPV) prediction models have been discussed. To make the application of advanced materials such as fibrous concrete, ultra-high performance concrete, FRP composites, etc., it is important to comprehend the existing blast/shock-resistant shelters and their response under such loading. The shelters are primarily designed by incorporating features of the materials like high degree of deformability/ductility, use of the shock-isolation panels and the mechanism for controlling crack formations. Finally, conclusions and recommendations for future studies are summarised. This paper presents prospects to engineers, town planners, researchers, policymakers and members of the core drafting sectional committees to understand the phenomenon of the blast and extreme loads induced out of it.

Seismoacoustic Monitoring of Underground Explosions at Redmond Salt Mine, Utah, United States

<p>Underground blasting within an extensive tunnel complex occurs as part of regular operations at Redmond Salt Mine, located in central Utah, United States. During the period of October 2017 – July 2019, we monitored these explosions using seismic and infrasound sensors. The experiment recorded approximately 1000 mining-related blasts as well as several hundred small earthquakes that naturally occur in the monitoring region at source to receiver offsets of 3-25 km. The data collected early in the experiment allow us to explore the characteristics of infrasound signals generated in subterranean tunnels, which show a variety of interesting characteristics, including components related to the structure of the underground tunnel complex, and a time-varying propagation efficiency. We present analyses that attempt to explain these properties. In addition, the data collected during the experiment allow us to test location algorithms at local distances by comparing computed locations with those taken from ground-truth logs. Finally, comparison of the tectonic and explosion signals allows us to examine possible discrimination methods that will effectively differentiate explosions from earthquakes at local distances.</p>