Application of NSR-AISC Method in Reserve Estimation and Technical Economic Evaluation of Low-Grade Polymetallic Deposits: Taking a Low-Grade Copper-Molybdenum Mine in Guangdong Province as an Example

The development and utilization of low-grade polymetallic deposits with strategic mineral resources is one of the important measures to alleviate the current high dependence on strategic mineral resources in China. However, domestic mining enterprises and most mining consulting and design institutes usually use general industrial indicators to carry out reserve estimation and technical and economic feasibility studies on low-grade polymetallic deposits, which cannot truly reflect the economic value of such deposits. The article expounds on the definitions of net return value (NSR) and on-site total maintenance cost (AISC) of common ore smelters in the evaluation of overseas mineral resources. Taking a low-grade polymetallic copper-molybdenum mine in Guangdong Province as an example, comparing the research results showed the NSR-AISC method and the general industrial index method in low-grade polymetallic deposit. There are huge differences in the results of reserve estimation;through the further introduction of Taylor’s formula and the research results on the relationship between investment intensity and production scale, a more reasonable mine life and investment scale are recommended, and a more in-depth comparative study has been carried out in the dimension of technical and economic indicators. Based on the comparative study of the above two methods in reserve estimation and the evaluation results of technical and economic indicators, the author believes that the NSR-AISC method can better reflect the true value of low-grade polymetallic ore projects, and should be popularized and applied in resource evaluation and development practice. This article further describes the application status of the NSR-AISC method for reserve estimation and the evaluation of technical economic indicators, and suggests the main points that should be paid attention to in the use of the NSR-AISC method.

Land use data generalization indices considering scale and land use pattern effects

Land use generalization indices are critical for producing normative multi-scale land use databases and maps,but there is still not a national criterion for these indices in China.Previous studies on land use data generalization indices often neglect macroindices such as area proportion of land use types and map load,and also ignore landscape effects on land use generalization indices.Here we constructed an index system of land use data generalization from macro-and micro-perspectives,and examined scale and landscape effects on land use data generalization indices based on the countrywide multi-scale land use data samples.We formulated relationships between land use data generalization indices and both scale and land use pattern metrics.We defined thresholds of land use data generalization indices on scales of 1:50000,1:100000,1:250000,and 1:500000.We verified our methodology and index thresholds through generalizing a county land use database.