The unknown soldier may well have been in that casualty count, his body somehow missed by stretcher parties who collected the dead and wounded when the shelling ended.
The soldier was uncovered two days before Anzac Day beside an old German trench and just a few hundred metres away from the Messines Ridge British Cemetery, which is maintained by the Commonwealth War Graves Commission.
Inside that resting place lies the New Zealand Memorial, where the names of 827 soldiers who died in or near Messines in 1917 or 1918 are carved in stone panels.
Confirmation the remains were those of a New Zealander rested on the discovery of two metal shoulder badges showing the soldier was an infantryman.
Forensic studies on the skeletal remains by Flemish experts in Belgium provided the NZ Defence Force with the sketchy details about the soldier's age, height and likely cause of death.
But he will remain "known only to God" - the phrase that defines soldiers who have no known grave, or whose identities are unknown.
He was the second New Zealand soldier found on the Western Front battlefield in the last 18 months. In July last year the remains of a New Zealand Rifle Brigade soldier were located during excavations for a new water treatment station.
A company which scans building sites for unexploded munitions detected the fallen soldier. A New Zealand Rifle Brigade hat badge, personal material and the remains of a uniform were recovered with the body.
That soldier was laid to rest at a formal ceremony in February at the Messines Ridge Cemetery.
Besides the battlefield casualties, a well-preserved German bunker and approach trench has been uncovered on land opposite the New Zealand Memorial.
The system was found by archaeologists commissioned by the contractor laying the water pipeline. Though the bunker is on private land, the local council wants to protect the discovery for visitors.
Though Messines is known for heavy loss of life, New Zealand soldiers fought with distinction in the battle, getting the upper hand over German forces to take control of a strategic ridge.
The battle began early on the morning of June 7, 1917, and within a few hours the New Zealanders had secured the town.
The key to their success was the laying of massive mines placed under German lines by tunnellers.
The heavy casualties came from the retaliation of German artillery bombarding the newly captured areas. Old photos of the battlefield show a barren landscape, with trenches protected by dirt mounds.
John McLeod, director of heritage, commemorations and protocol with the NZ Defence Force, said the young New Zealander would get a dignified burial and be remembered alongside the other unknown soldiers.
It was quite possible, Mr McLeod said, that more remains of New Zealanders would be found.
"The assumption is there's still quite a few bodies there."