the present invention embraces apparatus for the production of mineral fibers . an electrically heated bushing for the maufacture of glass fiber comprises an electrically conductive bottom wall having orifices for the passage of streams of molten glass therethrough for attenuation into fibers and upwardly extending , electrically conductive , sidewalls . each sidewall has an outwardly extending , electrically conductive flange . the bushing further comprises an electrically conductive material added to a portion of each flange to lower the electrical resistance of said portion to establish desired electrical current flow distribution in the bottom wall .