Peirce-Smith converters built in 1911. Each shell is 37 ft. 2 in. x 10 ft., with 44 tuyeres. It blows 60 tons of matte + 6 tons of quartz rock, wich are converted into 5-6 tons of converted matte. So, to fill the converter with converted matte, 300 to 400 tons of raw matte are added step by step, and blowed during a total time of 30 - 50 hours.