In the scrap-melting operation of shaft furnaces, an operation technology with use of 100% small size blast furnace coke for solid fuel instead of typically utilizing foundry coke has been established. An operation technology with use of 100% steel scrap without using return scrap containing 3-4 % carbon for ferrous raw material, and 70% or more of steel scrap consists of shredder scrap, has been established as well.<br>This technology was first developed with one-stage tuyere operations using only lower tuyeres. Next two-stage tuyere operations using lower and upper tuyeres has been developed to explore more efficient operation.<br>In the two-stage tuyere operation, the number of pipes, the diameter, and the protruding length of the upper tuyeres were examined as parameters, an operation technology with high efficiency was established, which enabled us to achieve high productivity and low coke ratio.