Remediation of the old mine 'Kaisergruben' near Gersdorf (Saxony)

The two shafts I and II as well as the surface structures of shaft II and the waste rock pile of the Kaisergruben near Gersdorf (Germany) are legacies of the black coal mining industry. The sinking of the two shafts was started as early as 1871 by the Kaisergrube Coal Mining Association. Mining operations were discontinued on 01.03.1930 due to the economic situation.

The rehabilitation of the legacies of the 'Kaisergrube' has been carried out under the ERDF project "Prevention of risks from abandoned mines" in the Operational Programme of the Free State of Saxony for the funding period 2014 to 2020 (with funding until 2023).  

Due to its scope, the overall project was divided into 3 sub-projects:

A – Demolition of Shaft II with surface rehabilitation
B – Safeguarding of shafts I and III
C – Safeguarding of the Kaisergruben waste rock pile

In July 2019, G.E.O.S. was awarded the contract for the engineering services for the entire project by the Saxon State Mining Authority. The beginning of the work was required to start in the fourth quarter of 2020. In November 2020, the Saxon State Mining Authority awarded the services for subproject A as a whole and for subproject B for shaft II to a contractor. Until then, in addition to the classic service phases for the building demolition and surface remediation at the site of Shaft II, extensive exploration and sampling work was carried out on the building structures and the backfill. Drilling and trenching work was done in the area of the two shafts as well.

Within the scope of the construction works in the sub-objects A and B, services of the site management, the local construction supervision as well as services according to the construction site ordinance were provided. The works on the contracted execution services have been completed in 2022.

For Shaft I and the waste rock pile, the engineering services up to the implementation planning stage have been provided in this ERDF measure. In 2021, G.E.O.S. were carried out extensive geotechnical investigation and research works for subproject C. As a result of this, conclusions will be drawn on the stability of the slopes and the measures required to ensure the long-term stability of the dump body.