The Institute of Geodesy and Mine Surveying of the Technical University of Ostrava performs long-term monitoring works and evaluates the effects of undermining in the Ostrava-Karviná coal-field, a major industrial conurbation in the north-east of the Czech Republic. Local extraction of bituminous coal has had significant effects on the surface relief. Actual undermining effects are monitored on selected built objects on a regular basis. Some of them are public buildings, roads, listed historic monuments, and buildings of cultural or historic value. Damage to the buildings, etc. can be eliminated to some extent by prudent planning of extraction works in space and time and by applying appropriate protective measures.