Abstract: The old room and pillar mining methods were commonly used by the local medium and small coal mines in Yuyang district of northern Shaanxi province. There is bigger security hidden danger at coal pillar stability, which had affected later replacement mining of coal pillars. Based on the long time effect analysis of coal pillars, the paper pointed that the long-term stability of narrow coal pillar in “mining 12 remaining 8” was better than that of rectangular coal pillar in room and pillar mining. The good stability of strip coal pillar has given the basic condition under the premise of the later guaranteed mining technology and capital in strip mining. On this basis, the paper has given a working face ventilation method of replacement mining, a filling method, and a specific mining way of advancing filling and back coal pillar replacement. The study has provided a kind of mentality for coal pillar stability and increasing the rate of recovery in protecting water mining at northern Shaanxi province, and had a certain significance.

Key words: Protecting water mining, strip coal pillar, coal pillar replacement, advancing filling