Discovery and characteristics of the super-large Yong'an iron deposit in Benxi, Liaoning Province

The Yong'an iron deposit in Liaoning is the southwestward deep extension of Nanfen iron deposit — China's largest open-pit iron mine, and represents a typical Anshan-type iron deposit. The ore bodies occur in stratiform-stratoid forms, with a general NNW strike and a SW dip, comprising three individual iron ore layers designated from bottom to top as Fe1, Fe2, and Fe3. They present an overall dip angle of 40-50°, a controlled length of 2 347.12 m, and an average thickness of 167.64 m, with a thickness variation coefficient of 41.90%. The average grades of ores are 32.03% of TFe and 22.54% of m Fe, with grade variation coefficients of 4.13% for TFe and 27.61% for m Fe. The ore bodies occur at depth of 665.53-2 168.59 m, with elevation values between -234.35 m and -1 517.36 m. The dominant ore type is magnetite quartzite (magnetite ore), showing relatively uniform grade distribution. During the period of 2021-2025, follow-up exploration utilizing deep drilling confirmed the deposit as a super-large iron deposit. Its discovery not only provides a successful model for deep prospecting in the peripheral areas of existing mines, but also secures sustainable resources for aging mines, thereby contributing significantly to the sustainable development of national economy.