The second rotary kiln operated in 1971, while the caustic magnesia grinding, sieving and packing installations were introduced in 1972, when the company entered the difficult and specialized international market of ground caustic magnesia.
The dense media separation unit started to operate in 1973 taking advantage of the difference between the specific gravity of magnesite and the gangue material. The construction of the second classification – preselection unit started in 1975 and was completed in 1976 remarkably boosting production.
In 1977, following long tests outside Greece, automated laser-based photometric ore sorters were installed and operated in Yerakini for the first time in the world. The overall installation was based on the different reflectivity between magnesite and waste rock. The installation of photometric ore sorters continued in 1979 with the addition of three new units.
In the same year (1979) the biggest investment ever implemented by the company was completed, the third rotary kiln producing over 200 tons of deadburned and caustic magnesia per day, which included an electrostatic dust filter for dedusting the kiln flue gases.
In 1980 GRECIAN MAGNESITE S.A. purchased the mining rights and production facilities of the neighboring mine at Kastri, Polygyros – Northern Greece from the American-Austrian company Magnomin. As a result, the overall deposits of the wider area of Yerakini are today exploited by a purely Greek company.
In brief, the present calcination capacity of the company, which also defines the capacity for the production of end products, is as follows:
• Three rotary kilns for the production of deadburned or caustic magnesia with a capacity of 420 tons / day
• One shaft kiln for the production of caustic magnesia with an overall capacity of 50 tons / day
• A modern automated double inclined shaft kiln for the production of caustic magnesia with a capacity of 100 tons / day
The successful progress of the company has continued after 1981. More specifically, during this period the company made some very important investments concerning the installation of additional photometric ore sorters and magnetic separators, the installation of electrostatic filters in rotary kilns No1 and No2, as well as the increase of the storage capacity with the addition of new warehousing capacity for the end products. At the same time, the transportation capacity of the company was increased with the purchase of 12 new dumper trucks carrying 50 tons each.