Introduction of belt press-filter Larox PF-50 at «Ellatzite-Med» Flotation Plant (Bulgaria) in 2009 provided for production of copper concentrates with moisture content of 6–8 %, meeting the market requirements. Installation of press-filter decreased power costs by several fold, and produced a positive effect on flotation processing regime. The article describes the results of press-filter operation testing, depending on various factors (slurry density, filtration time, material pressure, air pressure, air-drying time, etc.). Investments into press-filter provide for successful operation of «Ellatzite-Med» Flotation Plant in succeeding years.