The Nkwala Cases young uranium occurrence lies about 6.5 kilometres west of Penticton, British Columbia. This occurrence consists of four defined areas of uranium enrichment in postglacial sediments: the Nkwala South, Nkwala Side Basin, Nkwala P. Line, Nkwala Centre and Nkwala North. This occurrence lies at the northwest end of a 2 kilometre northwest trending area of erratic uranium and thorium occurrences. The Nkwala Cases young uranium occurrence was examined in late 1970s by D.G. Leighton in response to uranium anomalies discovered during reconnaissance geological, geochemical and prospecting.

Regionally, the area is principally underlain by medium grained intrusive rocks of the Middle Jurassic Okanagan batholitic complex and Bromley batholith, which to the south cuts Carboniferous to Permian Kobau Group metasedimentary rocks. The Okanagan batholitic complex consists primarily of biotite granite and granodiorite, locally porphyritic. The Bromley batholith consists of hornblende biotite granodiorite, quartz diorite and granite. Both are massive, light grey weathering, medium to coarse grained and equigranular. Intrusive rocks in the vicinity of the Nkwala Cases uranium occurrence are highly fractured and altered. On its southern margin, the Okanagan batholitic complex is in contact with an overlying assemblage of Eocene volcanics and sediments of the Penticton Group and rhyolite and rhyolite tuffs comagmatic with the Eocene Shingle Creek porphyry. At the base of the Penticton Group lies the Eocene Kettle River Formation, consisting of granite boulder conglomerate, arkose, volcanic wacke and rhyolite breccia. The Kitley Lake Member of the Marron Formation and Nimpit Lake Member of the Marama Formation comprise the primary Penticton Group rock types nearest the Nkwala Cases young uranium occurrence. The Kitley Lake Member consists of massive, yellow to buff, trachyte and trachyandesite with conspicuous feldspar and biotite glomerophenocrysts in a fine-grained matrix. The age of the Kitley Member ranges from 52.9 Ma (biotite) to 44.2 Ma (whole rock). The overlying Nimpit Lake Member is composed of recessive, reddish, amygdaloidal trachyandesite with minor intercalated pyroclastic deposits.

The Nkwala occurrence is a fluviatile-type young uranium showing where groundwater flow and organic sequestration are the dominant depositional controls of uranium in soils underlying swamp.

Several small areas of uranium enrichment occur in soils along a 3.0 kilometre north-south trend. The following is a table of five augerhole sample locations from Culbert, 1979:

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1 2 3 4 5 6 7

Nkwala North 47500 5.5 2.5 0.0118 0.0130 082ENW087

Nkwala Center 22500 Surface 3.0 0.0079 0.0102 082ENW088

Nkwala P. Line 5000 - 3.0 0.0126 0.0184 082ENW089

Nkwala South 20000 2.8 3.0 0.0098 0.0270 082ESW188

Nkwala Side Basin 6000 3.5 1.5 0.0104 0.0153 082ESW188

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Where: 1. Name 2. Area in square metres 3. Average depth of uraniferous layer below surface (metres) 4. Average thickness of uraniferous layer (metres) 5. Average uranium assay in per cent 6. Maximum uranium assay in per cent over 0.5-metre 7. MINFILE number reference.