Experimental research was carried out using representative samples of copper processing waste and the manganese processing waste disposed in Georgia to achieve secondary recovery of valuable metals from the waste. Joint autoclave oxygen leaching of different compositions of low-grade ores and waste using microwave treated samples was studied to assess recovery of metals from waste and low-grade ores. The data showed that complex utilisation of manganese and pyrite bearing waste can form the basis for a low-cost and environmentally-friendly industrial production of manganese oxide concentrates and low-carbon alloys, sulphur and copper compounds, and concentrates for gold and silver extraction. The developed methods can partially replace the standard technologies of ferroalloys industry, which uses reducing manganese oxides by carbon. This would significantly decrease the carbon monoxide and carbon dioxide emissions during production of ferromanganese and metallic manganese while reducing the emission of greenhouse gases and mitigating global warming.