Abstract: Apparatus for producing mineral fibres from silicate raw materials such as basalt by blast drawing.When blast drawing is used to produce mineral fibres from basalt, there is arranged between the entry zone (26) of the chute (16) and the exit zone of the nozzle slot (10) of the blast nozzle unit (8), this slot forming the fiberization duct, a guide cell (13). The relative position of the side walls (29) of the guide cell is freely adjustable, so that desired flow conditions can be set and also the exit direction of the exit flow bundle (31) and hence the web formation can be controlled. As a consequence of a lateral distance (a) of the exit orifice (28) of the guide cell (13) relative to the entry flow bundle (27) additional secondary air is sucked in, which has a further cooling effect on the fibres.