CH8 Exploration for Gold – Skarn – Nueltin Lake, Nunavut, Canada


GamX CH8 Gold Skarn Neultin Lake 1982 GSC Campsite

In 1982, ground follow-up to GSC airborne survey uranium and magnetic anomalies1  in the Sandybeach Lake (Nueltin Lake) Area led to discovery of mineralized calc-silcate boulders containing up to 80 gpt Au, 600 ppm U, W (scheelite), 390 ppm Mo and Co2.  The boulders occur within a magnetic high, adjacent to white, uraniferous, tourmaline bearing syntectonic granite. Outcrop exposure is less than one percent in the area. Mineralized outcrop sources were not discovered until drilled in 2008.

Although the area is covered by distally derived surficial deposits (sandy tills, eskers and glacial outwash), the altered, mineralized “discovery” boulders appear locally derived. Host rocks are favourably reactive metasediments, producing positive magnetic anomalies due to elevated pyrrhotite and magnetite, and are spatially associated with granitoid rocks and thrust faults.

GamX CH8 Gold Skarn Neultin Lake NWT Canada

 

 

The Sandybeach Lake occurrence is considered significant yet, despite almost 30 years of exploration, remains relatively poorly understood. Originally categorized as a skarn-type, several geological features have been shown to depart from conventional deposit classification. Both mineralogy and geochemistry are complex.3   Minerals which accompany native gold and uraninite (see polished section photo) may include: pyrrhotite, arsenopyrite, chalcopyrite, pyrite, cobaltite, cobaltpentlandite, pentlandite, loellingite, galena, molybdenite, tellurides (Fe, Ni, Pb), scheelite and silver. This suite results in several potential pathfinder elements: U, Au, Ni, Co, As, MO, W, Pb, Se, Te and REEs3.

 

As the U-Au association is not always present in all occurrences in the area, radioactivity (due to uranium) is not considered the ONLY guide to gold concentrations. However, it provides an extremely useful first–pass exploration tool, especially when combined with magnetic methods, and other geochemical pathfinder elements. Future exploration recommendations include ground spectrometry as follow-up to airborne eU anomalies which remain unexplained3.

The regional geology for the area is shown on the right.

Magnetic total field contours for the boulder discovery area are shown in the inset on left.

 

The uranium “discovery profile” from a single flight line (indicated in yellow) passing over the area shows the high eU, especially relative to eTh, as indicated by the whopping eU/eTh ratio anomaly.

CH8 Gold Skarn Nueltin Lake airborne fight line profile

A polished section photo reveals sulphides and tiny gold grains within uraninite crystal

 GamX CH8 Gold Skarn Neultin Lake gold in uraninite photo

 

Similar gold-uraninite-polymetallic prospects occur elsewhere, including the Gillander gold occurrence in northern Manitoba, also discovered through follow-up to anomalies detected by GSC regional airborne gamma ray/magnetic surveys2.

 

1. Carson, J.M., Holman, P.B., Ford, K.L., Grant, J.A. and Shives, R.B.K., 2002. Airborne gamma ray spectrometry compilation series, Dubawnt River, Nunavut-Northwest Territories, Geological Survey of Canada, Open File 4197, Scale 1:1,000,000.

2. Charbonneau, B.W. and Swettenham, S.S., 1986. Gold occurrence in radioactive calc-silicate float at Sandybeach Lake, Nueltin Lake area, District of Keewatin; in Current Research, Part A, Geological Survey of Canada, Paper 86-1A, pp. 803-808.

3. Jiricka, D.E., 2013. Independent technical report on the Nueltin Lake Project, Nunavut, Canada, for Uru Metals. Report NLP 2013-01

4. http://www.urumetals.com/media/70291/nueltin_lake_project_43101_final-11.06.13.pdf