The UNFC system and (RE) assessment of chromite resources of India

摘要

The term reserve and resource are used to signify the estimates of quantity of minerals present in ore deposits. These estimated quantities of minerals have been classified according to their economic significance or commercial extraction potential. Classification of reserves and resources is a complex exercise. Various factors affect this classification from the stage of reconnaissance to exploitation, which includes geological, mining, processing and marketing complexities of the ore deposit. The other factors that influence the classification of reserves, into different categories are probability (i.e. assurance of appraisal), economic feasibility, technological viability and the degree of reliability of all these factors. Political and socio-economic conditions also play an important role in deciding workability of the specific mineral deposit. In fact, the reserves of an ore body can never be exactly known, untill it has been mined out. Thus only an estimate of the underground reserves can be made. Such estimates will naturally differ in reliability and depends on the quantity and accuracy of data collection with respect to variability of the deposit. In the recent past, several classifications of mineral resources have been suggested. But none of theie classifications are true representative of the ore deposits, mis may be attributed to the presence of large components of subjective element in them. Worldwide, more than 150 country-specific classifications are in use with different terms and definitions. The limitations and variation of country-specific classification of mineral reserves/resources are mainly due to variation in terminology, definitions, norm for categorization and applicability. The limitations are also partly due to diversity in the nature of mineral deposits, workability and non-availability of precise geo-mathematical models. In the present work, classification of reserves/resources of chromite presently prevailing in India and the revised classification in accordance with the United Nation's Framework Classification system (UNFC) are discussed. The Indian Bureau of Mines adopted UNFC system for preparation of national mineral inventory on chromite.