Abstract: The present invention concerns a glass fibre manufacturing plant comprising a forehearth (31) comprising a longitudinal wall provided with at least one burner assembly comprising: (A) a burner block (20) made of a refractory material and comprising a through-passage and comprising a hot surface (20H) forming a portion of the longitudinal wall (31 L); and (B) a burner sub-assembly comprising: (a) an oxy-burner (1) comprising a downstream end ending at a free end of the downstream end, wherein a cross-sectional area of said downstream end of the oxy-burner body decreases towards the free end of the downstream end; characterized in that, the burner sub-assembly further comprises: (b) a cooling unit (3) comprising: ?a cooling plate (5) comprising an aperture which geometry matches the geometry of the downstream end of the oxy-burner which is inserted in said aperture to form a thermal contact therewith; •a cooling channel (3C) defined by walls and comprising an inlet (3U) and an outlet (3D) for circulating a refr