Abstract: The Pulang porphyry copper deposit in northwestern Yunnan Province is located in the middle section of the Sanjiang metallogenic belt in Southwest China. Through the survey of the rock mass structure of the 20 ~ 30 boreholes in the mining area and the petrophysical test , a large amount of data such as structural plane inclination, spacing, opening degree and rock uniaxial compressive strength have beencollected. After preliminary statistical analysis of the various data, it was proved that the structural surface of the rock mass was developed in the area. From the perspective of factors such as the degree of de-velopment of structural planes , the characteristics of spatial distribution , the location of the ore body , the occurrence (inclination) and other influencing factors, the overall situation is in line with the conditionsof the natural caving method. We should, however, also carry out investigation of rock structures in thetunnel in the future work, and strengthen comprehensive research in combination with ground stress, borehole logging and other data  and make full use of the data collected this time.

Key words: Pulang copper mine, investigation of rock mass structure, rock mass structural surface, rockmass quality