In 1922, the Kailuan Mining Bureau office building was erected.The bureau's logo was designed by a Briton; it had two concentric circles representing the two companies' cooperation and a diamond in the center representing the Kailuan coalfields. The dynamic movement for taking back the ownership of Kaiping Mine had ended in failure, and in the joint operation of Kai and Luan. These two modem Chinese-estab-lished mines, both fell into the control of foreigners, a humiliating episode in the history of Chinese industrial development. When the two companies united, they stopped competing and gradually grew to be north China's largest coal enterprise as its turnover and market both grew. On December 12, 1948, when Tangshan was liberated, all the mines were handed back to the people.