Hu, J, Li, S, Li, P, Lin, F, Xing, Z, Peng, F, Lin, Z, Bao, J & Yu, Z 2016, 'Research on quality factor for evaluating stability of high and steep rock slope fractured by underground mining', in PM Dight (ed.), APSSIM 2016: Proceedings of the First Asia Pacific Slope Stability in Mining Conference, Australian Centre for Geomechanics, Perth, pp. 663-670, https://doi.org/10.36487/ACG_rep/1604_45_Hu (https://papers.acg.uwa.edu.au/p/1604_45_Hu/) Abstract: Dahongshan iron ore mine, in China, is a mine that operates both open pit and underground mining at the same time. The ultimate slope will be 435 m high with an overall slope angle of 47°. Underground mining is using the sublevel caving method. Secondary stress by underground mining may seriously deteriorate the stability of the slope. In order to monitor and evaluate the stability of the slope, based on the microseismic monitoring system with 18 sensors installed in the slope, using the calculation method of the amplitude’s attenuation and frequency domain of seismic wave, this paper deduced calculation formula of quality factor based on the dynamic blasting location and uniaxial sensors. This paper obtained continuous dynamic three dimensional quality factor value of the slope rock mass for evaluating the stability and damage degree of the high and steep slope. The results revealed that the quality factor of the rock slope was generally stable in 2015, indicating that there were minimal secondary stress impacts from underground mining. The slope is, so far, still stable. Keywords: high and steep slope, quality factor, open and underground united mining, microseismic monitoring