ABSTRACT
The paper submitted describes development of the design of a railway tunnel situated in an undermined area with unrecorded underground extraction of brown coal. It was both rampant mining probably in the 17th and 18th centuries, carried out in the upper seam, which was manageable for primitive equipment up to a depth of about 25.0 m, and organised extraction in the 19th century and at the beginning of the 20th century, in the second seam, roughly 10.0–12.0 m under the upper seam. Unfortunately, only partial records of this mining remain. Using the information available, the tunnel alignment was selected so that it lied beyond the undermined area. About 50 investigation boreholes came across no sign of mining in this area. Nevertheless, when work started it was discovered that the tunnel passes partially through an area affected by deep mining. This fact had to be dealt with in the design. The paper describes the measures introduced and the experience gained from the work.
