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Table 1 Concentrations of natural radionuclides in the mine rock samples (Bq kg−1)

From: Radiological survey on radon entry path in an underground mine and implementation of an optimized mitigation system

  Min.–Max Average
Samples Ra-226 Th-232 K-40 Ra-226 Th-232 K-40 Ra-226 Th-232 K-40
Carbonate (Mn ore) C-1 15 ± 4 7 ± 2 245 ± 40 15–18 7–25 244–245 16 16 245
C-2 18 ± 4 25 ± 5 244 ± 42
Underlayer limestone (mullock) F-1 4 ± 1 6 ± 2 45 ± 9 2–6 5–8 45–102 4 6 75
F-2 4 ± 1 7 ± 2 62 ± 12
F-3 2 ± 1 8 ± 2 84 ± 13
F-4 6 ± 2 5 ± 1 102 ± 17
F-5 4 ± 1 5 ± 1 83 ± 14
Dogger limestone (mullock) D-1 2 ± 1 6 ± 2 88 ± 14 2–3 2–7 54–95 2 5 72
D-2 2 ± 1 7 ± 2 95 ± 16
D-3 3 ± 1 2 ± 1 66 ± 11
D-4 2 ± 1 5 ± 1 54 ± 10
D-5 2 ± 1 3 ± 1 58 ± 10
Black shale (Mn ore) B-1 18 ± 5 21 ± 6 299 ± 50 9–18 15–21 266–456 12 19 375
B-2 9 ± 2 16 ± 4 345 ± 60
B-3 12 ± 3 15 ± 4 266 ± 45
B-4 10 ± 3 16 ± 4 315 ± 54
B-5 13 ± 4 20 ± 6 456 ± 78
B-6 13 ± 4 18 ± 5 438 ± 74
B-7 11 ± 3 21 ± 5 451 ± 76
B-8 11 ± 3 19 ± 4 398 ± 69
B-9 13 ± 4 20 ± 5 415 ± 70
B-10 10 ± 3 20 ± 5 365 ± 62
Underlayer black shale (Mn ore) UB-1 11 ± 3 13 ± 3 255 ± 43 11–21 12–26 218–724 16 19 432
UB-2 21 ± 6 22 ± 6 345 ± 58
UB-3 18 ± 4 26 ± 7 218 ± 38
UB-4 20 ± 6 22 ± 5 654 ± 110
UB-5 11 ± 3 12 ± 3 724 ± 123
Puce greenish Marl (mullock) R-1 4 ± 1 8 ± 2 66 ± 10 3–6 6–8 66–84 4 7 74
R-2 3 ± 1 8 ± 2 74 ± 13
R-3 4 ± 1 8 ± 2 84 ± 15
R-4 5 ± 2 7 ± 2 78 ± 14
R-5 6 ± 2 6 ± 2 69 ± 13