The paper focuses on explosibility conditions in underground coal mines, the behaviour of explosions from initiating gas ignitions to violent dust explosions and the effectiveness and limits of operation of current designs of passive explosion barriers in suppressing the flame front. Areas of particular emphasis include:
passive explosion barriers are not designed to protect personnel in the flame initiation zone and its immediate surroundings;
passive dust and water barriers are generally considered ineffective against methane ignitions of the magnitude that can occur at the working face;
dispersal of suppressant from passive barriers is adversely influenced by equipment, including conveyor belts, located in the barrier zone;
current regulations in Australia do not specify the installation of barriers in all roadways leading to the face, so their use has a limited capacity to contain explosions;
a manifest design limitation is that passive barriers are restricted to one operation and are therefore ineffective against repetitive fire gases explosions; and
the practice of stone dusting in roadways inbye the barrier zone could conceivably adversely affect the operation of passive barriers.
The paper discusses performance evaluations made in full scale
explosion galleries and the use of alternatives to passive barriers,
including the installation of active barriers under some circumstances.