Abstract: Statistic analysis is made of the field number and storage space of various types of data, with the mineral prediction and assessment database as the study objective. It is found that qualitative data takes a leading position in both field number and storage space, which shows that the evaluation of the uncertainty of qualitative data is the key in the uncertainty evaluation in mineral resource prediction. The qualitative data are further classified into descriptive, classification code and series code types. It is found by the statistic analysis of the field number and storage space of the data of each type that descriptive data and classification data should be laid stress on in the uncertainty evaluation of qualitative data. The uncertainty evaluation is made on the classification codes and series codes by qualitative ranking and qualitative transformation and also on the qualitative data, with the strata and fracture orientation as the case.

Key words: Mineral resources prediction and assessment, Uncertainty, Qualitative data, Linguistic variables, the fuzzy Membership