What is the best way to prevent the blast from coming out of the hole?

Stemming refers to the use of inert materials, often soil or rock, to fill the space above the explosive charge in a blast hole. By doing so, it creates a barrier that helps contain the energy of the explosion and directs it into the ground rather than allowing it to escape into the atmosphere. This containment is crucial for reducing the risk of flyrock, which can be dangerous as it can travel significant distances from the blast site, posing a risk to workers and the surrounding area. Additionally, effective stemming contributes to better fragmentation of the rock, making the overall blasting operation more efficient and controlled.

Using blasting mats or controlled detonation can also play a role in managing the effects of a blast. Blasting mats are often deployed to further manage flyrock and overhead hazards by absorbing the energy of the explosion. Controlled detonation techniques involve precise timing of blast charges to ensure safe operation, but these approaches do not directly prevent the blast from venting out of the hole in the manner that stemming does. Therefore, stemming is recognized as the most effective method for ensuring that the explosive energy is directed appropriately and safely during a blast operation.