Coal mining at the site in the east of Germany left soil layers looser than those found in normal terrain, creating technically demanding construction conditions, ABO said.
ABO Wind is currently working on foudnations for two of the five Senvion turbines at its 16MW Forst Briesnig I project, it added.
The site was restored after mining company Lausitz Energie Bergbau stopped operating there, and it was used for agriculture.
But mining coal from depths of 95 metres has left earth layers looser than normal, site manager Tobias Bünning explained.
The developer is using water to flush gravel to depths of between 40 and 60 metres before compressing the loose soil.
ABO Wind is also hammering 32 concrete piles, each between 15 and 21 metres long, into the ground, to keep the foundations the stable.
It added that independent analysts will then examine whether the soil is stable enough for construction can continue.
ABO Wind expects the project to be commissioned later this year.
Ute Simon, head of the developer’s Berlin office, said the company can learn from its experience at the Forst Briesnig I site to develop other former coal mining sites.
"In Lusatia (south-eastern region of Brandenburg), there are numerous areas [where] lignite was formerly mined. Many of them are ideal as a location for wind farms," he explained.