Szukana fraza: [Abstract = "The results of the calculations are presented with tabular data and simplified ventilation diagrams. The creation of at least one large\-diameter opening and the upgrading of the main ventilation fans will ensure a minimum of proper functioning of the ventilation system. The drilling of a further opening will ensure that there is sufficient air in each ventilation area \- an increase of 50% in the mine's air volume will be achieved."]