Long term radon monitoring in the Bozkov dolomite caves in the context of the geological situation

This presentation summarized results from a proof-of-concept LiDAR survey and data processing, as well as long-term radon concentration monitoring in the Bozkov dolimite caves. These caves are situated in a Lugian region, in the area geologically called the Krkonoše-Jizera crystalline unit. Carbonate rocks occur in discontinuous streaks and lenses in this area. The lens in which the Bozkov caves were formed is 300 m in length and has a maximum width of about 150 m. The cave is permeated by calcareous and siliceous dolomite lenses from the Silurian age, surrounded by phyletic shales. The bedrock below the underground areas is the major source of radon. The environment of caves is typically characterized by 100% humidity, and the number of aerosol particles is around 102 times lower than outside (but the number of free ions is higher). The concentration of radon in the Bozkov dolomite caves may reach levels tens of thousands Bq/m3. The methodology for effective dose from radon estimation for cave guides is based on integral radon activity concentration measurement cV,Rn (integral RAMARN detectors) and evidence of working hours spent in the underground. Continuous radon measurement has been taking place here since 2003, and the measured concentrations form a complete set of data that was processed for the purpose of estimating and predicting movements in the earth's crust. Monitoring by integral monitors at basic communication (ventilation) nodes in the cave can also show how in-outside temperature changes affect air mass movements in a given cave, if we have a cave model available. 2 years ago, the continuous measurement was extended to a total of 7 positions in the cave system, and the measurement results allow a better understanding of the cave ventilation. The presented contribution introduces 3D cave system visualization (LiDAR technology), embedded in a geological environment following the results of in situ gamma spectrometry (surface above the cave) and continuous radon activity concentration measured by a set of TSR probes.