Abstract: A method is provided for improving the uniformity of the surface weight of a mineral wool mat. The mat is produced from a mineral melt which is converted into fibers, these fibers being introduced into a gas-formed stream providing a transport medium for these fibers. The transport medium and the mineral fibers carried thereby are transported to a moveable collector band on one side of which the mineral wool is deposited so as to form the mineral wool mat, the transport medium being caused to pass through the collector band by means of a fan or the like. The method comprises measuring at least one variable which is characteristic of the transport medium and which varies in relationship to the amount of mineral wool deposited.