The Lady D occurrence is located on the eastern slope of Mount Brenton, approximately 3 kilometres north east of Holyoak Lake.

The area is underlain by volcanics of the Devonian Nitinat Formation, Sicker Group. An exhalative iron formation is associated with a jasper unit. The unit is mapped at the contact of cherty tuffs above, and intermediate volcanics below. It appears to pinch and swell, with observed thicknesses up to 10 metres.

Work done on the showing in 1953 by Ladysmith Development Ltd. indicated that the iron zone extended along strike for 540 metres (Buckham, 1953, Map A).

Through 1984 to 1986, BHP-Utah Mines completed programs of geochemical sampling, airborne and ground geophysical surveys, geological mapping and 16 diamond drill holes, totalling 6317 metres.

In 1986, massive magnetite up to 8 metres thick was intersected in a drill hole by Utah Mines Limited. Up to 2.5 per cent pyrite was present along fractures. An old adit and dump in the same area showed samples of massive magnetite breccia containing up to 20 per cent pyrite with traces of chalcopyrite. Assay values were up to 0.05 per cent copper and 0.74 grams per tonne gold (Assessment Report 15749, page 14). Another nearby drill hole intersected similar mineralization. Moderate quartz veining with pyrite is present in the footwall andesite.

Zones of crackle brecciation occurring in the andesite contain magnetite, pyrite, chalcopyrite and malachite. One of these masses (probably to the northwest of the iron zone?) assayed 8.6 per cent copper, 42.86 grams per tonne silver and 3.22 grams per tonne gold (Assessment Report 15749, page 11).