Abstract: An apparatus and method which provides for controlled melting of both components of coal-ash, as well as the melting of selected additives, the melted coal-ash with additive being immediately available to a conventional fiberizing spinner stage. An arc furnace provides a shallow vat for molten pig iron. A first chute allows for introduction of coal-ash into the vat, and a second chute allows for the introduction of selected additives into the vat. The molten pig iron quickly melts any coal-ash and additive entering the vat, and the molten coal-ash/additive thereupon spreads out across the surface of the molten pig iron (the molten pig iron having a much higher specific gravity). In order to ensure that the molten coal-ash/additive has a predetermined fluidity at an adjacent spinner stage, the furnace is provided with a specially structured spout located above the spinner stage.