河钢股份：控股子公司乐亭钢铁4号高炉前期已经投产

Group 1 - The core point of the article is that Hebei Iron and Steel Co., Ltd. announced the successful ignition and operation of the supporting project for its subsidiary, Letin Steel's No. 4 blast furnace, which has already commenced production [2] Group 2 - The company is actively engaging with investors through an interactive platform to provide updates on its operational developments [2] - The successful ignition of the blast furnace indicates progress in the company's production capabilities and infrastructure [2] - This development may enhance the company's overall production efficiency and output in the steel industry [2]