Point of Ayr Colliery, near Prestatyn, closed in 1996 after more than 100 years of mining.
Most boys from the adjacent village of Ffynnongroyw followed their fathers and grandfathers down the pit.
However, there are fears that younger residents are in danger of forgetting the area's mining heritage.
Mike Jones, secretary of the Ffynnongroyw Mining and Village Heritage Group (FMVHG), said the pit opened in the 1880s and at its peak employed 500 workers.
He said Ffynnongroyw is packed with miners' cottages and "the sense of community must have been enormous" during the pit's hey-day.
"Ffynnongroyw was built as a mining village," Mr Jones added.
"Going back 30 years or so, it was predominantly Welsh-speaking, but we have a very transient population now and lots of people have moved away.
"The memorial is about bringing back the identity of the village.
"All the heritage is passing out of living memory.
"If you don't do something to preserve it, it's going to go.
"I think the younger generation of the village aren't aware of the heritage."
When the pit closed, only a plaque in the village centre marked the rich industrial heritage.
Now, the pit's old headgear will be erected alongside the coast road between Ffynnongroyw and Prestatyn, as a lasting memorial.
It is hoped there will also eventually be information boards and a seating area.
The FMVHG has raised about Â£4,500 towards the project, and rural development agency Cadwyn Clwyd has provided more than Â£6,000.
About 60 local people saw Flintshire councillor Carolyn Thomas cut the first sod on the new site on Tuesday.
Before installation, the headgear will be refurbished and painted by engineers.
Work on a memorial to the last operational deep pit in north Wales is under way, in a bid to celebrate the "identity" of a Flintshire village.