procedures for the control of dust and harmful gases during shotfiring in companies of the mountain and tunnel with small wetterfeuchten

摘要

In the control of the dust and noxious gas in blasting in mining and tunnelling operations with slight atmos.humidity, using cartridges filled with solid, finely-divided alkaline earth chlorides and wetting agents, the relative humidity is increased to min. 80% in the air at the site and in the adjacent 30-60 m. Thisis carried out by introducing a mist of water under the roof or injecting water into the ventilation line of a separately ventilated operation, 1-2 min. before blasting. Raising the relative humidity makes it possible to use these cartridges under normally dry conditions, since the hygroscopic salt is more effective in removing noxious gases and water helps to settle the dust.