Maintenance and Monitoring

Maintenance of the Unflooded Part of the Mine and Monitoring of the Impact Area of the Idrija Mine

CUDHg Idrija, by a decision of the Government of the Republic of Slovenia in 2014, became responsible for the continued maintenance of the unflooded part of the mine and the implementation of monitoring in the impact area of the Idrija Mine. With the transfer of employees from Rudnika živega srebra Idrija d.o.o. - in liquidation at the end of 2016, it became a fully operational public institution.

Although the mine is closed and flooded from the XVth to the IIIrd horizons, due to the specific nature of the mine, the deposit, and the geological characteristics of the area, continuous monitoring is necessary as it is located beneath the town of Idrija. The portion of the deposit above the IVth horizon will remain unflooded, requiring constant dewatering and maintenance. Carrying out maintenance of the unflooded part of the mine and monitoring the impact area of the mine within the legally defined scope is thus one of the core activities of CUDHg.

Maintenance works include:

  • maintenance of underground structures with a total length of 5764 m (main shafts, blind shafts, galleries, chutes, and haulage tracks),
  • maintenance of underground equipment (hoists, locomotives, etc.),
  • maintenance of the hoisting system and pumping station in the Borba Shaft (Francis' Shaft),
  • maintenance of the main ventilator in the Inzaghi Shaft,
  • maintenance of the compressor and pressure vessels,
  • Maintenance of electrical installations and equipment enabling water pumping, ventilation of the mine, access to the mine, and maintenance of external structures.
  • maintenance of surface structures.
  • Monitoring of the mining impact zone includes:
  • Visual monitoring,
  • geodetic monitoring,
  • geomechanical monitoring,
  • groundwater monitoring, and
  • environmental monitoring.


Even after the completion of all closure works, it is necessary to continue with the implementation of measurements (monitoring) until the results prove that ground movement above the mining site has completely ceased or that measurements over a longer period show no changes. It is also necessary to continue monitoring pollution levels in all environmental components and assess its impact on human health. The duration of monitoring is not time-limited.

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