In the early 1970s, Loesche faced a new challenge: improvements in cement kiln technology necessitated the construction of ever larger mills. Loesche’s response to this development was to invent the four-roller mill and introduce a modular mill system. The four-roller mill quickly became a huge success on the international market. In order to provide their customers around the world with better local support, Loesche established subsidiaries in Spain and South Africa. In the late 1970s, Loesche’s engineers adapted the modular system for use in coal mills. After 35 successful years as managing director of the company, Ernst Guenter Loesche retired in late 1983.