Effects, Responses & Regulations Blasting Effects, Responses & Regulations

Blasting Uses Coal Mining Aggregate Mining Construction

Typical Blast Design

Confinement

Blast Logs

Distance from Blasting Key to Determining Possible Effects Permit Area

Spatial Considerations Most Affected (Ground Vibrations) Least Affected Most Affected (Air Blast) Mining Pit

Adverse Effects Ground Vibrations Air Blast Flyrock Fumes

Adverse Effects Airblast 1,100 fps Blast Home Body Waves 20,000 fps Surface Waves 5,000 fps

Ground Vibrations & Air Blast

Seismogram Shows Vibration Waves

Structure Response Amplitude - How hard they are shaken Frequency - How they are shaken

Flyrock - Debris from Blasting

Gases Released by Detonation

Noxious Gases Carbon Monoxide – CO Nitrous Oxides – NOx

Regulations: Ground Vibrations Limits – According to US Bureau of Mines Report of Investigation 8507, Appendix B (Z-Curve) Damage Threshold – 0.5 in/s

Z-Curve

Regulations: Air Blast Limit – 133 dB Damage Threshold – more than 140 dB

Regulations: Flyrock Overburden, stone, clay or other material ejected from blast site by blast force Blasting may not cause flyrock

Regulations: Flyrock Measures taken to reduce the risk of flyrock: Use blasting mats or other protective devices to prevent injuries or damage For vertical faces, check for loose, hanging material or other faults before loading the blast holes

Regulations: Fumes Conduct blasts so gases generated do not affect public’s health & safety Prevent effects from gases Vent gases Interrupt the path of gas flow Evacuate people from areas that may contain gases