PGG spokesman Tomasz Głogowski said that the shock then occurred 13 in the area of the exhaust wall 900 m underground. The shock had energy corresponding to about three degrees on the Richter scale.
– One person reported bruising after the shock, this person went to the surface and will be examined by doctors. The rest were safely withdrawn from the threatened area – said Głogowski.
Work on the mine wall has stopped. Counseling representatives from the mining industry will decide on their resumption. There is no information so far that the shock has caused damage to underground excavations or to the surface.
Shock is the most common cause of tragedy
Shaking is a natural phenomenon in the mining area. Their most common cause is the relaxation of the rock mass as a result of the exploitation of coal, which results in the release of the energy collected in it. Due to different geological conditions some shocks on the surface are felt strongly, others are weaker.
On August 11, in the Bobrek-Piekary mine, there was a shock of magnitude 3.5 on the Richter scale, which had affected residents of many urban agglomerations, including Bytom, Piekary Śląskich, Siemianowice and Chorzów. Chimneys and roofs are damaged in some places. A few days earlier, after the shock, 14 miners were withdrawn in the Rydułtowy Mine.
In addition to explosions of methane and coal dust, shocks and rock eruptions are the most common causes of mining tragedies. May 5 this year in the Zofiówka mine in Jastrzębie Zdrój five miners died as a result of an eruption of the rocks, two were rescued. The body of the last of the wanted aid workers was found by the rescuers on the eleventh day of the rescue operation carried out under extreme conditions, completed on 19 May.