Employer: Ellatzite-Med AD

Designer and contractor Geotechmin OOD

Project execution period: 1994 – 1997

Description of the project:

The industrial site of Ellatzite copper mine is located in the area of the Malak Iskar River catchment basin. The waters of the many gullies situated near-by pass through the mine's refuse dumps and the valley of the mine. They react with the sulfide minerals and the sulphuric compounds and thus acquire a clear acid character – рН = 2.5-3.5. This and the presence of heavy chemicals in the waters had been causing serious environmental problems in the valley of Malak Iskar River. In order to resolve these problems, Geotechmin developed the following two-step water treatment process:

• Collection of the clean river waters via a water collection and transportation system, and their exportation out of the mine's industrial site and into Malak Iskar River
• Transportation of the acid waters via underground collectors and PVC-pipes to tailings pond "Benkovski - I" located near Mirkovo Flotation Plant  on the south side of the Balkan mountains

Conducted works:

• Making of forest roads – 25 km
• Making of concrete drain canals – 6.5 km
• Installation of water collection systems – 12 units
• Making of cascade ponds – 4 units
• Driving of drainage gallery with cross section 7.2 sq.m. – 820 m
  - Erection of a temporary platform and a portal to the gallery by a blast-drilling method – 1,200 cub.m. of rock material
  - Concrete and shotcreting works along the encountered fractures
• Drilling works with diameter 300 mm and length 70 m – 6 units
• Making of a chimney
• Installation of pipelines and drainage systems – 8 km
• Construction of energy dissipators and air shafts using acid-resistant materials