Borehole logging for uranium by gamma‐ray spectrometry

Loevborg, L.; Nyegaard, P.; Christiansen, E.M.; Nielsen, B.L

doi:10.1190/1.1441108

Cited by 8 publications

(3 citation statements)

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“…A number of samples with relatively high U and/or Th is nevertheless observed in the sheared vo1canic rocks (fig. 3) contributing about 10 per cent to the U tonnage in the Kvanefjeld area (Løvborg et al, 1980). Yttrium follows this trend indicating the possibie presence of radioactive rare earth minerals.…”

Section: Yttrium Zirconium Niobium Thorium and Uraniummentioning

confidence: 82%

Distribution of characteristic elements in the radioactive rocks of the northern part of Kvanefjeld, llímaussaq intrusion, South GreenJand

Kunzendorf

Nyegaard²,

Nielsen³

1982

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About 600 one-metre drill core sections from lujavrites and country rock xenoliths of northem Kvanefjeld were analysed for Li, Be, F, Na, K, Ca, Ti, Mn, Fe, Cu, Zn, Y, Zr, Nb, Pb, Th and U. The samples were taken from 7 of the 23 drill cores of the 1977 drilling operations. The analysed rocks were divided into seven rock groups: (1) naujakasite lujavrite, (2) naujakasite lujavrite with visible villiaumite, (3) arfvedsonite lujavrite, (4) arfvedsonite lujavrite with visible villiaumite, (5) volcanic rocks (lava and gabbro), (6) sheared volcanic rocks, and (7) sheared volcanic rocks with visible Nb minerals. Naujakasite lujavrite (both groups) has high concentrations of Th, U and Y at relatively low Zr contents. Arfvedsonite lujavrite (both groups) has high Zr contents but lower contents of Th, U and Y than naujakasite lujavrite. Thorium, U and Y generaIly accumulate at upper levels of lujavrites, mostly at the contact to xenoliths. This is thought to be caused by temperature gradients at the contacts. Zirconium enrichment occurs at lower levels of mainly arfvedsonite lujavrites expressing gravity settling of eudialyte during crystallisation. Naujakasite lujavrite is regarded as the youngest and most differentiated lujavrite. Microscopic and chemical investigations of two transition zones of lava and gabbro at contacts with lujavrites revealed typical features of metasornatic action, Le. formation of aegirine, arfvedsonite, albite, microcline, pectolite and other minerals. A general increase of sodium from the unaffected volcanic rocks towards the lujavrite contact is accompanied by a depletion of silicon and other elements. Niobium mineralisation is confined to sheared marginal zones of country rock xenoliths. Resource evaluation for Zr, Nb, Zn, Be, F, Li and rare earth elements of the rocks of northem Kvanefjeld suggest Nb and rare earth elements as potential by-products of a possibie uranium extraction process of the Kvanefjeld ore, while F should be extracted for mainly environmental reasons.

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Section: Yttrium Zirconium Niobium Thorium and Uraniummentioning

confidence: 82%

Distribution of characteristic elements in the radioactive rocks of the northern part of Kvanefjeld, llímaussaq intrusion, South GreenJand

Kunzendorf

Nyegaard²,

Nielsen³

1982

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“…Nearly all results in the present study were obtained by gamma-ray spectrometry (GRS) at the Risø National Laboratory (Løvborg, 1972). The thorium standard, NBL 74, is stated to contain 1010 ± 30 ppm with 95% confidence.…”

Section: Analyticai Techniques and Accuracymentioning

confidence: 86%

Evolution of Th and U whole-rock contents in the Ilímaussaq intrusion

Bailey¹,

Rose-Hansen²,

Løvborg³

et al. 1981

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A great variety of investigations have been made on the distribution of Tb and U in the Ilimaussaq alkaline intrusion, South Greenland. The major emphasis has been placed on economic assessment of the Kvanefjeld uranium deposit (Sørensen et al., 1974) but attention has also been given to the Tb and U contents of rocks and minerals outside the deposit (Buchwald & Sørensen, 1961; Sørensen, 1962; Hamilton, 1964; Gerasimovsky, 1969; Bohse et al., 1974; Steenfelt & Bohse, 1975). In the present study, we present Tb and U values largely obtained by laboratory gamma-ray spectrometric (GRS) analysis of a large collection of representative samples taken from all rock types of the intrusion. The results are discussed in relation to current knowledge and ideas on the petrologic evolution of the Ilimaussaq intrusion.

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“…Several authors (Conaway et al, 1980 andL^vborg et al, 1980) have published papers concerning the quantitative interpretation of gamma-ray spectral logging data. In this paper, the interpretation is based on the calculated effect of a single given horizontal layer containing homogeneously distributed radioisotopes on a cylindrical probe centered in a drill hole.…”

Section: Introductionmentioning

confidence: 99%

A comparison of stationary and continuous gamma-ray spectral data with cores in granites

Schimschal¹

1991

Open-File Report

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This report describes a study undertaken to compare quantitative gammaray spectral analyses of naturally occurring radioisotopes from borehole logs and from cores in the laboratory. Continuous logging was accomplished by centering selected energy windows on the 1.46 megaelectronvolts peak for potassium-40, 1.76-megaelectronvolt peak for uranium-238, and the 2.62 megaelectronvolt peak for thorium-232. In addition, a number of stationary spectra were obtained at depths corresponding to preselected core locations. The drill hole used for the study was the Granite Mountain No. 2 test borehole near Jeffrey City, Wyoming. The borehole, entirely in granitic rocks, was logged to a depth of 463 meters using a sodium-iodide crystal, with a diameter of 32 millimeters and a length of 100 millimeters. The crystal was calibrated with point sources. The results indicate the advantages of running a continuous log in conjunction with stationary spectra or cores in order to determine boundaries of the anomalies. Quantitative results for cores and inhole stationary spectra are in reasonable agreement for both potassium and thorium. The scatter obtained for uranium may be indicative of nonhomogeneous distribution in the rock matrix or possibly chemical redistribution with time.

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Borehole logging for uranium by gamma‐ray spectrometry

Cited by 8 publications

References 0 publications

Distribution of characteristic elements in the radioactive rocks of the northern part of Kvanefjeld, llímaussaq intrusion, South GreenJand

Distribution of characteristic elements in the radioactive rocks of the northern part of Kvanefjeld, llímaussaq intrusion, South GreenJand

Evolution of Th and U whole-rock contents in the Ilímaussaq intrusion

A comparison of stationary and continuous gamma-ray spectral data with cores in granites

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