The $43,887 geophysical surveying project uses a fluxgate gradiometer to measure magnetic variations in the earth that indicate where soil has been disturbed and from that, Dr Bader, of Auckland-based Archaeological Solutions Ltd, can identify potential graves.
Once he has walked over the cemetery with his machine, with fellow archaeologist Daniel Parker to take GPS readings, the data is downloaded to a computer which produces a map.
That map is then laid over an aerial photograph of the cemetery, in collaboration with Otago University's Southern Pacific Archaeological Research, to provide a map of all graves, marked and unmarked.
He said records for the Kyeburn Diggings cemetery, for example, were destroyed by fire but this week the grave-hunters identified about 73 unmarked graves.
Project manager Janice Remnant, of the Central Otago District Council's Ranfurly service centre, said many cemetery records had been destroyed by fire or flood while others were becoming fragile.
Once Dr Bader's work is finished, the administrators of each cemetery will decide what to do to mark those graves.
In some cases, where cemetery records exist, names could be put to newly identified unmarked graves.
The project got an $18,335 grant from Central Lakes Trust.
Eight cemeteries in the district are controlled by trusts which together funded $5550 of the project. The Cromwell, Vincent and Maniototo community boards each gave $6000 and the Roxburgh board gave $2000.
