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File Created: 16-Dec-1986 by Gary R. Foye (GRF)
Last Edit:  23-Jul-2018 by George Owsiacki (GO)

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Name EXO, CHES Mining Division Omineca
BCGS Map 093F042
Status Prospect NTS Map 093F05E
Latitude 053º 24' 53'' UTM 10 (NAD 83)
Longitude 125º 42' 28'' Northing 5921822
Easting 320045
Commodities Tungsten, Copper, Molybdenum, Silver, Zinc Deposit Types K06 : Sn skarn
K07 : Mo skarn
Tectonic Belt Intermontane Terrane Stikine
Capsule Geology

The Exo or Ches occurrence area lies approximately 80 kilometres south of Burns Lake and is accessible via an all-weather paved highway south from Burns Lake to Ootsa Lake crossing Francois Lake using the Francois Lake ferry. A private barge operated by the Cheslatta Carrier Nation can be used to access the network of logging roads south of Ootsa Lake and the Ches property.

The region in which the Exo showing occurs is within the Intermontane Belt, underlain dominantly by Middle Jurassic volcanic and sedimentary rocks of the Hazelton Group (Naglico Formation). These assemblages are overlain by the Eocene to Oligocene Ootsa Lake Group and Miocene plateau basalt. Intruding the Hazelton Group is a belt of granodiorite, diorite and quartz diorite plutons of the Late Cretaceous Chelaslie River-Tetachuck Lake Plutonic Suite and Eocene feldspar porphyry.

The Exo showing is underlain by sedimentary and volcanic rocks of the Lower Jurassic Hazelton Group, intruded by a granodiorite intrusion which outcrops about 800 metres to the east of the showing.

Two zones of mineralization comprise the showing. A steeply dipping mixed hornfels-calcsilicate skarn assemblage with bands of quartz-garnet-diopside-pyrrhotite skarn contains pyrite, scheelite, chalcopyrite and sphalerite. About 200 metres to the east, a bleached and silicified hornfels zone hosts a stockwork of quartz-pyrite-chalcopyrite-scheelite-molybdenite veinlets. In the skarn showing, mineralization is exposed over a width of 22 metres with a tungsten oxide grade of 0.25 per cent across the zone. Within this zone, a two metre width averages 0.56 per cent tungsten oxide and 0.44 per cent copper (Assessment Report 15129). The stockwork mineralization sampled over a 350 metre width in a logging road cut in 1989 assayed 0.62 percent copper, 0.05 per cent molybdenum, 0.04 percent tungsten and 14.40 grams per tonne silver (George Cross Newsletter January 16, 1989).

In 2014, a 1.5 metre chip sample from the Exo road quarry yielded 1.25 per cent zinc, 0.16 per cent copper, 0.12 per cent tungsten trioxide (WO3), and 2.6 grams per tonne silver. Trenching adjacent to the main access road returned chip samples grading 0.33 per cent copper, 3.73 grams per tonne silver and 0.03 per cent WO3 over 4.5 metres, including 0.61 per cent copper, 7.4 grams per tonne silver, and 0.05 per cent WO3 over 1.5 metres. In addition a 1.5 metre chip sample from the eastern side of the property returned 38.1 grams per tonne silver and 0.1 per cent zinc from altered granitic intrusive rock. A grab sample located several hundred metres southwest of previously documented mineralization returned 0.33 per cent copper, 0.1 per cent WO3, 0.21 per cent zinc, and 5.2 grams per tonne silver, showing the system remains open for exploration (Assessment Report 35268).

In the mid-1980s, the first known exploration at the Exo copper-molybdenum-tungsten skarn-stockwork prospect took place after Esso Minerals Ltd. staked the ground in response to high copper-zinc values in lake sediment samples. Follow-up work by Esso included 15 kilometres of soil sampling and magnetometer and VLF-EM geophysical surveys. In 1985, road construction uncovered several new mineralized skarn and stockwork zones at the Exo prospect that were then staked. In 1986, prospecting and 1:10,000-scale geological mapping discovered more skarn outcrops. In 1987, 26 kilometres of magnetometer and VLF-EM readings and soil samples were taken at 25-metre intervals along the cut-lines. A total of 848 soil samples were collected. The range of soil assays were up to 512 parts per million (ppm) copper, 39 ppm molybdenum, 124 ppm tungsten, 4306 ppm zinc, 2.4 ppm silver, and 310 parts per billion for gold (Assessment Report 17679). The geological mapping outlined a hornfels-skarn envelope, at least 1 kilometre wide, adjacent to the western margin of the Tetachuck North stock. Within this envelope, a wide molybdenum skarn and stockwork zone was discovered that averaged 0.52 per cent copper, 0.07 per cent tungsten oxide (WO3), 0.008 per cent molybdenite (MoS2), and 5.14 grams per tonne silver over a distance of 350 metres (Leask, 1987b) as reported in Assessment Reports 33702 and 17679.

In 2000, Keefe conducted exploration on his Ches property in the vicinity of the Exo copper-molybdenum, tungsten skarn-stockwork zone (Assessment Report 26354). This work involved the collection of 18 bedrock samples, 1 silt sample and 39 infill soil samples. The program confirmed the presence of a significant B-horizon soil anomaly at the Exo.

In 2008, Scarlet Resources Ltd. used the Ches property as a listing property but other than a brief property visit, as part of the requirements to complete a National Instrument (NI) 43-101 report on the property, no work programs were completed under the agreement. During the Scarlet Exploration program, 20 grab or rock chip samples were collected. Eighteen of these were taken from the Exo skarn-stockwork zone, and the remaining two from a gossanous road quarry lying approximately 3 kilometres further west. The owner of the Ches property which encompassed the Exo showing is listed as Ralph Keefe.

In 2010, Teck Resources Ltd. personnel completed a one day Ches property visit with the claim owners Ralph Keefe and Shawn Turford. The party collected a total of 5 rock samples from both the Main and stockwork zones. Results confirmed the presence of significant copper mineralization in both zones. In early December 2011, a property visit on the Ches occurrence was completed by Riverside Resources and Antofagasta Minerals. Several mineralized samples were collected for analysis in the Exo showing area despite deep snow and winter conditions that did not allow the proper sampling of the showings.

In 2014, Northern Abitibi Mining Corp. optioned the property and in September and October conducted a trenching, surface sampling, and mapping program to better assess the historic mineralized zones. Seven trenches were completed within a 1.5 by 0.5 kilometre area and 274 surface rock samples were collected and assayed. Trenches and available surface exposures were mapped and sampled, and the existing Exo road quarry exposure was chip sampled.

EMPR ASS RPT *15129, *17679, 26354, 30575, 32256, 33702, *35268
EMPR EXPL 1986-C329; 1992-69-106
EMPR FIELDWORK 1992, pp. 475-481; 1993, pp. 9-14; 1994, pp. 167-170, 193-197
EMPR OF 1991-17; 2002-11
GSC MAP 1131A; 1424A
GSC P 90-1F, pp. 115-120
PR REL Northern Abitibi Mining Corp., Oct.30, Dec.*17, 2014