What is the maximum moisture retention percentage in coal dust to avoid explosion risks?

To prevent explosion risks in coal dust, it is crucial to maintain a specific moisture content. The maximum moisture retention percentage identified as critical for minimizing explosion hazards is 20%. At this level, moisture helps to dampen the dust particles, reducing their potential to become airborne and ignitable. Maintaining moisture below this threshold ensures that the coal dust remains less flammable and helps to create a safer working environment in underground mines.

While other percentages may seem viable, they either do not provide enough moisture to effectively suppress the dust or could lead to conditions that increase the risk of ignition and subsequent explosions. Thus, the correct maximum moisture retention percentage of 20% is integral to effective safety protocols in underground mining operations.