[1][2] In 1957, Lee used his own capital from money he earned in the confectionery business to acquire a cement factory in Samcheok, Gangwon Province; its owners at the time were eager to sell due to frequent labour disputes and the poor state of the physical plant.
[3] That factory had started operations in 1942 under the ownership of Onoda Cement during Japanese colonial rule over Korea.
[4] Lee searched out former Onoda engineers in order to rehire them, in particular Oh Pyong-ho, "supposedly the only competent cement engineer in post-colonial South Korea"; Oh accepted the job offer.
Lee then began repairs to the facilities with the aid of engineers from Germany's Polysius Company, resolved the labour disputes, and revamped the recruiting programmes; he hired heavily from the local Samcheok High School, and many of his new hires' fathers had worked for Onoda in the past.
[7] Among the three, Sampyo Group's bid was successful, and in September 2015, Sampyo Group formally acquired a 45.07% stake in Tongyang Cement, with the Korea Development Bank Sigma Private Equity Fund acquiring another 9.88%, in a ₩794 billion deal.