| dc.description | This work analyzed samples from a niobium mine in Brazil which produces massive quantities of non-processed
waste (NPW) each year. Due to concerns about the environmental impact of stacking up this material in the longterm,
investigations have had been made to evaluate its re-use options. Nevertheless, there are no regulations
from the Brazilian National Commission of Nuclear Energy about commercializing this sub-product which has
highly variable radiological activity because of the different lithologies present in the mine. Thus, the activity
concentrations of 238U, 232Th, 226Ra, 228Ra, 228Th and 40K of the naturally radioactive ore (53 boreholes) and of
the NPW (8 samples) were measured. Radiological hazard indices, radium equivalent, internal and external
hazard and their equivalent doses were also calculated. Moreover, the X-ray diffraction, depth and coordinates of
all samples were used to identify radioactive prone areas in the mine. For the NPW samples, the activity concentrations
(in Bq/kg) were, on average, 64.9 of 238U, 104.8 of 226Ra, 1813.9 of 232Th, 1292.2 of 228Th, 1224.3
of 228Ra and 1184.2 of 40K. The analysis showed great variability between samples and the results can be used to
evaluate possible uses such as building materials or foundation for roadbeds. | |
