Visual Simulation And Study Of Reserves Estimation Of Shaxi Porphyry Copper Deposit In Anhui Province

With the development of the national economy, the contradiction between supply anddemand of mineral resources become increasingly prominent.To alleviate this problem，while strengthening efforts in mineral exploration, more fundamental way is how toimprove the utilization rate of mineral resources. To achieve sustainable development ofmineral resources,"Digital Mine" came into being, and three-dimensional simulation ofthe deposit is the basis for achieving this goal. On the basis of the solid model of the orebody, we can further estimate reserves of mineral resources. Foreign markets only admitreserves of mineral resources estimated by geostatistical method, although the methodwas introduced to China nearly three decades, its application is very limited ingeological survey system. In this paper, Anhui Shaxi porphyry copper deposit is theobject of study, on the basis of fully collecting and collating geology information, usingmining software SURPAC as a research tool, three-dimensional modeling and reserveestimation of the deposit are studied. The following results and understandings areobtained:(1)The geological database of Shaxi deposit was established. Three-dimensionalmodels of the important geological entities such as six major orebodies, stratum, rockand faults were built, the spatial morphology of the main orebodies and contactrelationships between them were stereoscopicly reproduced.(2)Based on the statistical analysis of the original samples, the suitable sample lengthof combination was identified, the sample data of drillings were combinatorial analyzed.Experimental variogram of tilt direction direction, strike direction and thicknessdirection of major orebodies were calculated, reasonable variogram model wereestablished, spatial variability of copper grade of the deposit is identified as follows:(a) the correlation of copper grade in Fengtaishan ore section is worst in tilt directionand similar between strike direction and thickness direction; the correlation of coppergrade in Tongquanshan ore section is better in strike direction and similar between tiltdirection and thickness direction.(b) When the distance is greater than101.787m in tiltdirection,60.288m in strike direction and105.543m in thickness direction of orebodies,the correlation of copper grade disappears in Fengtaishan ore section; when the distanceis greater than105.184m in tilt direction,80.528m in strike direction and82.737m inthickness direction of orebodies, the correlation of copper grade disappears inTongquanshan ore section.(c) The nugget constant C0is0.313both in Fengtaishan and Tongquanshan ore section. These variability characteristics indicate that the gradedistribution within a smaller range is very discrete, it recommends to strengthengeological work and encrypt sampling density for100m*60m in Fengtaishan ore sectionand100m*80m in Tongquanshan ore section.(3) The best continuity of grade changes of major orebodies were analyzed，furthercalculating parameters of anisotropic searching ellipsoid and doing cross-validation.From the cross-validation results, variance models are credible and reliable. Theestimation of copper reserves which above industrial grade is142350.330tons inFengtaishan ore section and316720.950tons in Tongquanshan ore section by usingOrdinary Kriging method. Compared to the results by traditional method of parallelvertical cross-section, relative error is only2.3%in Fengtaishan ore section and3.0%inTongquanshan ore section. This proves reserve estimation results is reliable by usingOrdinary Kriging method, futher validate the rationality of variance models.