The invention relates to a launder construction for the conveyance of molten metal. The metal flows in the lower part of the launder construction in a channel defined by a refractory mass, the launder being heat-insulated so that, in operating conditions, the metal forms a solid zone in the porous refractory mass. The essential features of the launder construction include a cover part that is provided with electrical resistors, ensuring that the metal remains melted and the launder sufficiently hot throughout the process, and a gas burner that prevents the metal from cooling under the effect of the gas flowing in the launder channel.