The gases present in a mine after blasting depend on factors including the mine geology and type of explosive used. Carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), ammonia (NH3), and hydrogen sulfide (H2S) are toxic gases which commonly require monitoring in post-blast atmospheres.
GAS DETECTION SOLUTIONS FOR POST-BLAST RE-ENTRY
Real-time monitoring for faster post-blast re-entry. improved worker safety. data-driven decision making.
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Learn more about Post-Blast Re-Entry in our application guide.
Request the Guide
Learn more about Post-Blast Re-Entry in our application guide.
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Post-Blast Gas Hazards & Challenges in Underground Mines
Every minute spent waiting for post-blast hazards to be cleared is a minute of lost production.
Every blast reshapes the environment inside an underground mine. Blasting releases a number of hazardous gases in high concentrations such as carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), hydrogen sulfide (H2S), which must be cleared from the mine through ventilation before re-entry is permitted.
In addition to toxic gas and dust from the blast, vibrations can result in ground instability, creating loose rock and other geotechnical hazards that must be identified before personnel can return to the face.
For example, Conspec has measured CO concentrations exceeding 500 ppm immediately following a blast, which is more than 10 times OSHA’s permissible exposure limit of 50 ppm and over double the NIOSH ceiling exposure limit of 200 ppm. Until hazardous gas levels are brought within acceptable limits, a mine remains inoperative, workers remain idle, and the costs associated with a lengthy downtime begin adding up. Returning to normal operation is essential, but traditionally, it’s anything but simple.
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Conspec's Post-Blast Gas Monitoring Solution
Improve post-blast visibility with scalable gas monitoring that supports safer, faster re-entry decisions.
Rugged Optio Multi-Gas Monitors
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Hazardous & Combustible Gas Sensors
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Environmental Sensors
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SCADA Command Center
Want to learn how? Download our Post-Blast Re-Entry application guide.
Benefits of Post-Blast Monitoring
Real-time post-blast gas monitoring and SCADA visibility improve re-entry speed, worker safety, and overall operational efficiency.
Increased Productivity
Faster re-entry decisions allow underground mining operations to resume production sooner, reducing idle time and lowering operational costs.
Maintained Safety
Real-time gas monitoring reduces the need for personnel to enter post-blast environments for manual verification using portable detection equipment. Conspec’s safety solution minimizes exposure to toxic and combustible gases.
Reduced Downtime
Personnel don’t have to wait for fixed re-entry periods or complete manual inspections while dust and gases are evacuated. Conspec’s real-time monitoring allows for faster, data-driven re-entry decisions to be made as soon as conditions are safe.
Lower Energy Demands
Integrated real-time monitoring means ventilation systems are managed based on actual post-blast conditions rather than fixed re-entry periods, helping reduce unnecessary runtime once gas and dust have been cleared.
Post-Blast Re-Entry Products
Explore our integrated gas detection, monitoring, network control, and SCADA solutions designed to support safer, faster post-blast re-entry in underground mining operations.
Frequently Asked Questions
What gases should be monitored after blasting?
How does real-time post-blast monitoring work?
Conspec places a battery-powered wireless monitor within 30 ft (10 m) of the blast face to measure atmospheric conditions in real time. The monitor communicates through the mine’s leaky-feeder network to a Conspec gateway, which communicates with our Senturion S950 SCADA software suite for remote monitoring in the control room.
How long should you wait before re-entering a mine after blasting?
There is no universal post-blast waiting period for every mine and blast. Some mines use fixed wait times, often 30–120 minutes, based on experience and ventilation calculations, but real-time atmospheric monitoring provides measured conditions that can help qualified personnel determine when contaminants have cleared and re-entry criteria have been met.
What hazards are present after blasting besides toxic gases?
Post-blast hazards go beyond toxic gas, including dust, debris, loose or unstable ground, poor visibility, oxygen-deficient air, damaged ventilation, open holes, and unexploded explosives or misfires. These hazards can remain after toxic gas concentrations have fallen and must be assessed before workers return to the affected area.
How does post-blast monitoring speed up re-entry times?
Real-time post-blast monitoring replaces time-based assumptions with measured atmospheric data, allowing operations to make re-entry decisions based on actual conditions at the blast site. When monitored contaminants have cleared and applicable re-entry criteria are met, workers typically return sooner than under a fixed waiting period. Historical data from multiple blasts can also help refine future blast planning and re-entry procedures.
Discuss your Post-Blast Monitoring Application
Every underground operation has unique ventilation, blasting schedules, and re-entry requirements. Our team is ready to help you design a post-blast monitoring solution tailored to your operation.
Complete the form below and a post-blast specialist will be in touch to discuss your application and requirements. We look forward to working together!