There was a countdown and a big bang as ammunition blew up in an explosion over 200 metres into the sky.

It is just another day for the 17 Wing Detachment in Dundurn, Saskatchewan. They are in the midst of Operation Rolling Thunder II.

"We are going to be disposing ammunition from a 76 mm weapons system that used to be used with the Cougar armoured car which is no longer used by the Canadian Forces," said Cpt Jordan Woodan, public affairs officer.

The high explosive squash head (HESH) ammunition came into use in the 30s, but Woodan said he estimates that the ammunition started to become obsolete in the mid-90s.

Although the Dundurn location is the largest ammunition depot in Canada, for space and safety reasons it is important to clear it out. The propellant in the explosions has stabilizers that degrade over time and can become dangerous.

"We are actually disposing of over 24,000 rounds of this ammunition," he said.

That means it is over 100 tons of explosives, not including the weight of the shell that holds it.

After burning or exploding the ammunition the officers must also pick up all the residue and dispose of it as hazardous waste.

The demonstration explosion on Tuesday was one of about 24 hits they do in a day.

"The crater it left afterwards was about two and a half meters in diameter," said Cpt. Jean-luc Degagne.

He said that they must also take sound into account. They have recently reduced their net explosives so that neighbouring communities will experience less of the noise.

This specific operation will finish in August, but explosions will certainly continue at the aptly named Destruction Range.

kmalone@rawlco.com