Sixteen metres below the surface of Townshend Island, the digging stopped – not because the crew had finished their job, but because it wasn’t safe to go further.
Using a Ferrex detector, a team of Air Force explosive ordnance disposal (EOD) technicians found a ‘hit’, indicating unexploded ordnance further beneath the ground.
Excavators slowly clawed away the earth, chasing the reading down to find an Mk-83 1000-pound bomb.
The Mk-83, containing more than 200 kilograms of high explosive, is capable of destroying fuel depots, aircraft on the ground and lightly hardened structures.
Unable to remove the bomb, the team’s next option was to detonate it in place.
However, this would risk creating a camouflet, or gaseous underground pocket, which might collapse, swallowing people or equipment.
So, the remediation team had to mark it as unrecoverable, allowing it to sit there forever.
This was not the case for seven other pieces of unexploded ordnance discovered during a remediation of the island’s impact areas, which are regularly used for target practice with everything from artillery rounds to rockets and naval gunfire.
The remediation team uncovered two Mk-82 500-pound bombs and five artillery rounds scattered across the 25-hectare impact area from April 26 to June 1.
Some were detonated in place with charges while others were removed and later blown up.
Similar remediation work is conducted on impact areas around Australia every few years to clear a range and ensure it’s safe for future bombing and ground access.
Every process involves detecting ordnance, assessing what and where they are, detonating in place or somewhere else – depending on the size – and verifying whether the land is safe again.
The situation on Townshend Island was damper than expected, so the team had to pump out water before locating the unexploded ordnance.
Once water was pumped out, the search could begin.
‘This is one task where all of our skills come together to complete a single outcome.’
EOD technicians then swept the ground, scanning for metallic signatures and indications that something lay buried below.
Plant equipment remained on standby until the area was cleared, then moved in to excavate once each of the seven ‘hits’ was marked.
Once they dug down to a munition, the ordnance would be detonated in place so as not to disturb its sensitive fusing.
Some of the smaller projectiles, when deemed safe to do so, were moved to a central location to be disposed of in a stack.
Senior EOD technician Sergeant Gavin Dunn was in charge of the EOD clearance and unexploded ordnance deep search activities, with the team camped out on Townshend Island.
This was his second posting with 65 Air Base Recovery Squadron, with eight years of experience under his belt.
“This is one task where all of our skills come together to complete a single outcome,” Sergeant Dunn said.
His team was paired with plant operators responsible for excavating down to the unexploded munitions, but also bringing in bulldozers once the area was safe.
These dozers were used to clear vegetation from the impact area so future explosions and hits could be clearly observed.
The Australians were also joined by a team of four US Air Force EOD technicians who requested to join and practise deep search for unexploded ordnance.
“That’s one thing on their ranges they don’t actually get to practise,” Sergeant Dunn said.
“We managed to get them hands-on and let them dig a hole themselves, but they also helped us with the whole range remediation.”
When the next barrage of unexploded ordnance accumulates and vegetation grows again across the island’s impact areas, another EOD team will be back to conduct the next remediation.
