IDNR Completes Quarry Inspection in McCook

Chris McCloud
IDNR Completes Quarry Inspection in McCook
MCCOOK, IL � The Illinois Department of Natural Resources� Office of Mines and Minerals (OMM) Blasting and Explosives Unit has completed its inspection of Hanson Material Service Corporation�s Federal Quarry in McCook, Illinois. A state inspector was sent to the quarry after the United States Geological Survey reported a seismic event in the area on Monday, Nov. 4. 

A two-day inspection found the quarry operated within the statutory limits for blasting and quarry operation, after reviewing the company�s blasting records and blasting measurement readings, which were taken properly. 

�The Office of Mines and Minerals takes the proper handling and use of explosives very seriously.  In this instance, our inspection found no violations of state law,� said OMM Blasting and Explosives Unit chief Mike Falter.

Illinois state regulations limit the resultant vibrations from surface blasting to one (1) inch per second at the nearest protected structure.  Measurements taken at the quarry on Nov. 4 showed the maximum blast vibrations at .35 inches per second at the nearest protected structure.  Measurement instruments at the quarry also picked up readings from a secondary event several seconds after the quarry blast took place. 

�Our review of quarry records does show measurement equipment picked up vibrations from a second and separate event approximately seven seconds after the initial blast.  What this secondary event was, or what caused it, is outside our regulatory expertise,� said Falter.

Quarries are required to use specialized equipment to measure blast vibrations and keep accurate records of all measurements for proper inspection.  Failure to keep these records properly can result in substantial penalties, including revocation of an individual blasters license.

A copy of the preliminary inspection report is available at this link:

For more information about administrative rules that govern the Illinois Blasting and Explosives regulatory program please visit
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