’’Processing Plant“ is a separate branch where coal processing and refining of raw coal from the open cast mines "B" and "D" from the Mining Basin "Kolubara" take place. This is necessary in order to get the assortment required for the supply of thermal power plants, mass consumption and industry.

’’Processing Plant” is comprised of the following organizational units: Centre for Technical Affairs, three plants and Centre for Coal and Wastewater Testing.
1. Centre for Technical Affairs performs production and technical, and technology development activities as well as investment construction, economic, legal, HR and general affairs
2. In Dry Separation, raw coal from the open cast mines from Fields "B" and "D" is crushed and sorted in order to provide coal assortment required for thermal power plants, mass consumption, industry and Heating Plant. 1st, 2nd and 3rd phase are operating with a total capacity of 4000 t/h.
3. Coal Refining Plant is comprised of four operational units, as follows:

– Wet Separation, where raw coal is cleaned in a heavy environment (suspension of water and sand) and prepared for the drying process. Beside washed coal, overburden, which is transported by cable railway to a dump site, and wastewater are separated during the wet separation process.
– Conveyor belts transport coal from Wet Separation to Drying Plant (which includes Sorting Plant). Coal drying is carried out in cylindrical autoclaves (steel vessels) with saturated steam at high pressure and temperature. Designed capacity of the Drying Plant is 855 thousands of tons. After drying process, coal is transported to a bunker with dried coal, and from there to the Sorting Plant where it is separated by assortments.
– Heating Plant is a thermal power facility with a capacity of 2x60 MW, intended for the production of heating energy required for the technological process in the production plants, as well as for the heating of industrial plants and Lazarevac municipality. Water used in steam boilers is supplied from a chemical water treatment plant with a capacity of 3 x 60 m3/h. Flue gases are filtered by the electrostatic precipitator before discharging through the stack. Ash from electrostatic precipitators and slag from the boiler are transported hydro-pneumatically to the ash dump. Waste water is treated in a separate plant.
– Operational unit Maintenance performs preventive and investment maintenance, production of spare parts for Wet Separation, Drying Plant and Heating Plant.
4. Rail transport conveys coal from open cast mines to the Wet Separation. It also ranks wagons of the PE "Serbian Railways" with dried coal for the Drying Plant station, wagons for "Nikola Tesla" Thermal Power Plant in Obrenovac in Wet Separation and wagons for the TPP "Kolubara" in Veliki Crljeni. This plant also performs the corrective maintenance of locomotives, wagons, tracks and overhead contact line systems.
5. The first accredited laboratory for coal quality testing in Serbia operates within the Centre for Coal and Wastewater Testing. From 22 to 23 thousands of coal samples and from 2.5 to 3 thousands of water samples are analysed in the laboratory annually.