THREE-DIMENSIONAL MODELING AND APPLICATION STUDY OF THE PORPHYRY-SKARN AU-COPPER DEPOSITS IN BEIYA, WESTERN YUNNAN, CHINA

The Beiya gold-polymetallic deposit, which located in southeastern Tibetan Plateau, China, is a world-class porphyry–skarn polymetallic gold deposit. For the past few years, the shallow part geological structure and resources of the deposit have been preliminarily revealed. However, the limited knowledge of the deep ore-controlling structures and mineralization conditions restricted deep prospecting. In recent years, we focused on the geological body from the surface to 1000 meters underground of Wandong Shan ore block, which is the largest deposit in the Beiya orefield. We adopted the geologic model building software SKUA-GOCAD and realized the stratum-tectonic-intrusion-ore body 3-D visualization of Wandong Shan ore block.

Based on drilling data and Sgrid of orebody, 3-D visualization of grade distribution model had been realized for the first time by using ordinary kriging interpolation method. We draw conclusions as follow: ① The SKUA-GOCAD software not only suitable for reservoir simulation but also could be applied in reserves rapid calculation. ②A deep buried fracture in Wandong Shan strike parallel to 40°had been speculated, which might be the target for further exploration; ③The mismatch between thick part of ore body and high garde sgrid indicate that Beiya gold deposit has suffered multistage mineralization.

The 3-D model might also be helpful for prospect areas determination. Gravitational prospecting and magnetic geophysical method corresponding to Wandong Shan orebody which shows high magnetic anomaly and low gravity anomaly. Therefore, we speculate that the high magnetic anomaly area and low gravity anomaly would be the metallogenic prospective area.