Study On Quantitative Assessment Of Undiscovered Mineral Resources

The quantitative assessment of mineral resource potential take the undiscovered mineral resources as target by means of prospects or tracts, and their main contents include how to confirm the space distribution of undiscovered mineral resources and to estimate their amount for improving integrated analysis extent in work district, establishing unified and standardized orefinding information platform, and serving for the prospecting investment decision and work arrangements. In this paper, adopt the three-part quantitative assessment method to develop the quantitative assessment of porphyry copper mineral resource potential in the typical metallogenic belt such as the middle–lower reaches of the Yangtze River for the first time, and point out that the three-part quantitative assessment of mineral resource potential make up a comprehensive decision-making problem which involves multi-levels and multi-factors such as collecting data of geology, minerals, geophysics, geochemistry, remote sensing, and scientific research, setting up space database, deposit models, and grade-tonnage models, educing mineralized information, application of mineralization theories, delineating and optimizing tracts, and estimating amount of mineral resources. The metallogenic system theory has been applied into three-part method for the first time. It was concluded that the undiscovered porphyry copper reserves in study district respectively would be 5,600,000 tons for 90% probability, 28,600,000 tons for 50% probability, so there would exist a good resource potential at the depth of 1000m depending on the theory of metallogenic system as guidance to know deeply porphyry copper mineralized laws in the Yangtze River, to set up porphyry copper deposit models and grade-tonnage models, to estimate number of undiscovered deposits in tracts by means of the subjective probability method, to simulate amount on Monte Carlo method. Baded on the geochemical block theory, author has delineated 4 geochemical blocks with the block lower limit 33×10-6, total area 14,259km2, and calculated respectively at the depth of 1000m rock blocks in study area that the Cu metal endowment 1,938,100,000 tons, undiscovered assessed resources 43,000,000 tons supposing mineralization coefficients 2.75%. Compared the three-part method with geochemical block method applied in quantitative assessment of porphyry copper deposits, it was predicted that there would exist a good potential especially in Echeng-Jiurui tract and Guichi-Tongling tract at the depth of 500-1000m, and also proposed that the developing direction of three part quantitative assessment in the future should be how to adopt different methods to delineate tracts and estimate number of undiscovered deposit, to improve the predicting precision and expand the scope of application.