Roșia Poieni copper mine

Roșia Poieni represents the largest copper reserve in Romania and the second largest in Europe having estimated reserves of 1.5 billion tonnes of ore grading 0.36% copper.[1] It is enclosed by eruptive sub-volcanoes Miocene rocks (micro-diorite or Fundoaia andesites).[1]

The Fundoaia body has the shape of a vertical column of 1,180 m (3,870 ft) in height (+1,030 m (3,380 ft) → −150 m (−490 ft)) and in horizontal plane having the following dimensions: 660 m (2,170 ft)÷740 m (2,430 ft)/820 m (2,690 ft)÷956 m (3,136 ft).[1] The eruptive body comes in contact (through the tectonic breccia) with andesite necks (Poieni, Curmatura, Melciu, Piatra Tichileu, and Jgheabului Hills) and with sedimentary Cretaceous rocks.[1] The porphyry copper deposit is made up mainly of fine disseminations, nests and veinlets (0.02÷3 cm) of pyrite, chalcopyrite, and magnetite; gold included in the chalcopyrite and pyrite, and secondary minerals: bornite, covellite, chalcocite, sphalerite, galena, molybdenite, germanite, malachite, azurite and is developed in microdioritic rocks.[1]

The ore extracted from the open pit is crushed in a gyratory crusher after being transported and stored in the crushed ore storage facility located within the processing plant site. The processing plant has a design capacity of 9 million tonnes extracted and processed per year, the process being made on 4 technological lines of 7,500 tonnes per day.[1] The plant was launched between 1985 and 1987. The ore is subsequently processed through a classical processing flow, with a two-stage grinding phase in two autogenous mills and in two ball mills, followed by flotation, which is performed in pneumomechanical cells (17 m² (180 sq ft)) where the primary concentrate is obtained, which subsequently is flotated in cells of 5.7 m² (61 sq ft) where a copper concentrate is obtained with a content between 16.5 and 20% copper. The concentrate is thickened in sided thickeners and filtered through a pressure filter (Larox).[1]

• Official site