Work History

Staked as Kobuk & Nidd cl (YA6587) in Sep/76 by Cominco L, which explored with grid soil sampling, mapping, bulldozer trenching, mag, EM and gravity surveys in 1978, 1981, 1982 and 1983. Cominco drilled 2 holes (503 m) in 1979, 4 holes (878 m) in 1981, 4 holes (1242 m) in 1982, 5 holes (1758 m) in 1983 and 3 holes (1186 m) in conjunction with geochem and mapping surveys in 1984 and performed road building in 1985. 
Cominco repaired the road and performed an IP survey in 1988, and drilled 2 holes (479.2 m) in the main zone in 1989 and six holes (1352.2 m) outside the area of known mineralization in 1990.

Capsule Geology

This large tonnage, low-grade zinc deposit is associated with basaltic volcanism along a late Devonian syndepositional fault which cuts Silurian to Late Devonian sedimentary and pyroclastic volcanic rocks of the upper Road River and lower Earn Groups. The altered, mineralized zone extends over 400 m of stratigraphic thickness, and has a strike length of at least 1500 m in a northeast direction. 
Hydrothermal minerals including quartz, iron carbonate, pyrite, sphalerite and minor galena have invaded and strongly replaced the host sedimentary rocks, and at depth, banded sphalerite- carbonate veins and carbonate breccias occur within the fault zone. Mineral zoning has been documented: chalcopyrite occurs only in the fault zone, galena is restricted to the deepest part of the deposit, sphalerite and quartz occur in the deep to intermediate parts and pyrite is the dominant suphide near the top. The Nidd deposit is inferred to be the same age as the Tom and Jason sedex deposits (Minfile 105O 001 and 019) at Macmillan Pass but differs from them in that all of the sulphides were deposited below the sea floor. 
Drillhole NB89-14 intersected a stockwork of high grade sphalerite-siderite veins cutting pyroclastic rocks at the base of the Earn Group. These rocks contained an average of 2.0% Zn over 63.7 m. 1990 drillholes encountered only a few short intervals of sphalerite-veined mudstone and appear to lie outside the main hydrothermal system.