Explosive ordnance exploration, exploratory drilling with core extraction, depth-appropriate backfilling with clay pellets and filter gravel, drilling of the TB 7 well, pouring of the foundation slab for the house, installation of the conveyor system with fittings.

After sinking the exploratory borehole with continuous core extraction and depth-appropriate backfilling with clay pellets and filter gravel, well borehole TB 7 was drilled as an air-lift drill. The borehole was sunk to 60 munter GOK with a diameter of 1200 mm, installed with steel pipes 813 x 10 mm and the annular space was grouted with a clay powder cement suspension. The borehole was then deepened to a final depth of 138 m with a 760 mm Ø, drilled out to 1100 mm Ø and with filters and solid pipes made of stainless steel and from 76 m up to GOK with solid pipes made of PVC/Noresta and two DF filters DN 65/ Norip developed at different depths. After introducing the filter gravel and carrying out the desanding and power pumping test, the valve section was built and the base plate was concreted. The well head was welded onto the 813×10 mm barrier pipe. The weld seam was then X-rayed.