germany-jena: construction work./ operational work in the old mine for the years 2023 to 2026./ the subject of the procurement is operational construction work to be carried out above and below ground in order to ensure public safety at s from old mines and underground cavities for the period 2023 to 2026 (4 years) in the free state of thuringia. further information on the type and scope of the service can be found in the tender documents.