The D1 (Deb) occurrence is located east of McMurdo Creek and approximately 4 kilometres west of Spillimacheen Mountain.

The area is underlain by a repeating sequence of dark-grey to black shales with interbedded limestones, alternating with thick-bedded, coarse-grained, grey to brown ortho-quartzite sandstone and grits of the upper Proterozoic Horsethief Creek Group.

Locally, a chalcopyrite-bearing quartz vein is exposed for approximately 50 metres and averages 0.9 metre in width.

In 1980, a select sample assayed 7 per cent copper, 0.4 per cent lead and 12 grams per tonne silver (Property File - First Nuclear Corp. [1980-01-01]: 1980 Summary Report on Project 11, Spillimacheen).

In 1979, Norcen Energy Resources Ltd. optioned the holdings of Cochrane Oil and Gas Ltd. between Vermont and Warren Creeks and carried out a program of geological mapping, prospecting, geochemical soil sampling, geophysics and diamond drilling. In 1980, Norcen continued to work on the same area with a program of geological mapping, regional and detailed geochemistry, geophysics and diamond drilling. In 1982 and 1983, additional programs were carried out on these claims by Cochrane Oil and Gas and Bluesky Oil and Gas Ltd., including diamond drilling. In 1979 and 1980, the First Nuclear Corporation staked a substantial number of claims, from McMurdo Creek at the north end to the northern boundary of the Cochrane ground just north of the Ruth Vermont Mines, following the results of a 1979 stream sediment geochemical survey. Field work in 1980 included geological mapping, prospecting and geochemistry. In 1981, the First Nuclear Corporation continued exploration of the DEB claims with geological mapping, sampling and prospecting. At the end of this program the size of the claim group was reduced to 376 units covering the favourable and anomalous stratigraphy. In 1982, MineQuest Exploration Associates Ltd., working on contract to Samim Canada Ltd., further explored the DEB claims, principally through geological mapping, prospecting, reconnaissance soil geochemistry, mostly on widespread contour lines, and rock-sampling and trenching. In 1983, work by Samim saw 7.7 kilometres of IP surveys completed; a total of 493 metres drilled in 11 BQ holes; and 1096 soil, 227 rock and 27 silt samples collected.