With modern explosives (ANFO and/or emulsion [or various mixtures of the two]), the amount of toxic gases or fumes produced from blasting varies according to the explosive mix, the degree of confinement in the hole, the amount of water in the hole and the sleep time of the explosive, among other factors.
It is always difficult to predict how much blasting fumes will be produced, and also how long it will take for the fumes to “clear”.
CO, CO2, NO2 and NO are common gases that need to be monitored however there could also be potential for SO2 and H2S when explosives are used in Sulphide-containing rocks. NH3 could also be a factor if lime is present due to cement.
Many Australian Mines now use dedicated, trained re-entry crews to check blast affected areas for fumes. These crews are usually either development charge-up or production blasting personnel and usually operate as “pairs” and operate to strict procedures. They usually have two persons per crew for safety, although often using only one gas monitor providing it is maintained, operated and calibrated strictly in accordance with the manufacturer’s requirements.
The GX-6000 Gas Monitor provides the user the flexibility for many different sensor configurations to match the gases needing to monitor. The unit is built tough and its durability in harsh environments makes it a good choice for post blast gas monitoring applications. The units boast a 24-hour run time and has additional features like, Man Down Alarm, Panic Alarm and Auto LCD Inversion. An optional Calibration and Bump Test Station is available to enable the monitor to maintained and compliant on site to ensure the required number of monitors are always on hand and ready for work.