One of the basic conditions creating the production capacity of hard coal mines is the front of mining works. This potential is measured by net daily output volume that can be accomplished from the front of coal wining operations. The length of the coal wining front is the sum of the width of winning faces and in practice is the sum of the length of longwalls. The article shows, in the form of charts and tables, the creation of average daily length of exploitation front in particular coal mines that have been analysed in division into groups according to cola companies that were established in 1993 until 2005.