Since 2019, when the site stopped being used for general landfill, years of settlement and the capping of certain areas has reduced the efficiency of the gas collection system which had been installed.
States Works is supervising the work to construct 20 new wells, with each being drilled one at a time.
Four have been completed.
‘Since it was last drilled we have raised all of this space, so the upper portion has no gas wells,’ said environmental monitoring technician Yannic Bearder.
‘This is the final height now.’
The work will not impact on members of the public walking around the Chouet headland or visiting the green waste site.
‘There is always potential of some gas coming up, but it is very unlikely. The worst part is probably just the smell,’ said Mr Bearder.
He said they knew what to expect during the drilling, as they had records of what was in the landfill site.
Plastic pipes are put down the holes and then gravel is poured in. Cement is put around the top of the pipe.
The extracted gas is burnt using a flare stack to control emissions of the methane produced as the waste breaks down.
Workers from South Tyne Drilling, a specialist UK contractor, have been brought to the island with one of its heavy duty drills.
The work will continue until next Friday.