Stráž pod Ralskem

 Print
Stráž pod Ralskem Area on the Map

Location: The Liberec Region, Česká Lípa area

Brief history

Mining took place here from 1967 until 1996. Since 1996, uranium has been exploited as a by-product of the remediation of the Stráž uranium deposit. 2,210 research bore holes and 7,684 mining boreholes have been drilled into this deposit. 35 leaching fields were established, covering an area of 700 hectares. The site’s mining area is 24.1 km2 and reaches a depth of 220 m beneath the surface. By 1996, 15,562 metric tons of uranium had been extracted.

Type of activity

Chemical uranium mining – The method; leaching out of underground uranium from surface bore holes (ISL) using acid leaching (leaching regent: H2SO4, oxidization material: HNO3).

Present-day conditions

The liquidation and rehabilitation of the extraction fields is underway, as well as a broader remediation of the mining area with an aim to:

  • remove the uranium enriched solutions from underground water
  • re-vitalize the district’s environment wherever affected by chemical mining.

The Environmental Problem and its Solution

Mine water

The underground water, approx. 186 mil. m3 at the Cenomanian and 80 mil. m3 at the Turonian aquifer is contaminated from the chemical mining of uranium.

Soil

Circa 186 mil. m3 of Cenomanian and 80 mil. m3 of Turonian residual technological fluids remained in the soil after chemical processing of uranium. During the mining operations, the underground was subject to 4,100 kt of H2SO4 (of this, 80% reacted with the ore and 800 kt remain in the form of loose H2SO4), as well as 312 kt HNO3, 112 kt NH3, 26 kt HF and 1.5 kt HCl.

Remediation is being carried out by pumping out and treating the water at the Desalination plant and the Neutralization and Decontamination plant. This evaporation technology works at a capacity of 5.5 m3.min-1. and is followed by crystallization, re-crystallization (crystal sulfate of ammonium aluminate) and the removal of salts and metals at an operational capacity of 5.5 m3. per minute, the results of which are further processed into both usable and non-usable products. The treated water is poured off into the Ploučnice River.

 
back