Inorganic fiber production burner apparatus and methods of use are disclosed. One burner includes a refractory block adapted to be in fluid connection with sources of primary oxidant and fuel, the refractory block having a fuel and primary oxidant entrance end and a flame exit end, the flame exit end having a substantially rectangular flame exit having a width greater than its height, the refractory block defining a combustion chamber and a second chamber fluidly connecting the combustion chamber and the flame exit end; and an oxygen manifold fluidly connected to the combustion chamber and adapted to route oxygen to the combustion chamber through a plurality of passages through the refractory block. This abstract allows a searcher or other reader to quickly ascertain the subject matter of the disclosure. It will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).