The Ridley Creek occurrence is located on the east side of Deception Mountain.
The area is underlain by metasedimentary rocks of the Proterozoic-Paleozoic Snowshoe Group, along the south margin of a granitic pluton informally referred to as the Deception stock.
Locally, bedrock exposures include skarn, calc-silicate schist, quartz-biotite schist and quartzite, locally cut by aplitic, pegmatitic and granitic dikes. Layering and schistosity show gentle to moderate dips to the southwest. Scheelite and molybdenite occur in skarn adjacent to a felsic intrusive.
The mineralogical study of drill core samples has provided sufficient evidence in support of a genetic model that includes the formation of skarn rocks by hydrothermal fluids related to the monzogranite/alaskite intrusion. A very simplified, general model of the scheelite mineralization includes two main stages.
The first stage of mineralization (prograde) included the formation of coarse-grained calcsilicate rocks (skarnoids) composed of variable proportions of garnet, vesuvianite, diopside, calcite, dolomite, plagioclase, and minor quartz, wollastonite, scapolite, titanite, chlorite, sulfides (pyrrhotite), apatite, and zircon after regional impure marbles. The prograde alteration in regional clinopyroxene-dominant calc-silicate had similar effects although the developed skarn assemblage has fewer leucocratic phases and contains mostly medium- to coarse-grained diopside, epidote (clinozoisite), quartz and plagioclase with minor actinolite, garnet, vesuvianite, chlorite and carbonates, and the accessory phases titanite and zircon. The first generation of scheelite was deposited at this stage, predominantly in the leucocratic skarn rocks.
The second stage of mineralization encompasses the development of retrograde skarn that overprinted all existing rock types such as biotite gneiss, clinopyroxene-dominant calc-silicate rocks, prograde skarn rocks, marbles and the monzogranite. The overprint encompassed extensive chloritization of the rock-forming minerals, breakdown of biotite, growth of the calcsilicate minerals diopside, actinolite and plagioclase, and the deposition of significant amounts of sulfides such as pyrrhotite, sphalerite and chalcopyrite, together with the much higher quantities of the second generation of scheelite. Calcite is variably present and titanite is an ubiquitous minor phase and likely the product of decomposition of mafic silicates and alteration of ilmenite.
Work History
The area has been explored in conjunction with the Fox occurrence (MINFILE 093A 211). The Fox property was optioned by Happy Creek Minerals Ltd. in December 2004 and an exploration program comprising grid layout, soil and rock geochemical sampling, prospecting, geological mapping and diamond drilling were completed through 2011. In 2006, a grab sample returned up to 0.26 per cent tungsten, 0.234 per cent molybdenum and 18 grams per tonne silver (Assessment Report 28982). In 2007, sampling of outcrop returned up to 0.88 per cent tungsten (Assessment Report 30824). In 2010, trenching returned values from 1.07 to 5 per cent tungsten trioxide, 0.07 to 3.9 per cent zinc and 8 to 1000 grams per tonne cadmium over 0.3 to 5 metre lengths (Assessment Report 32054).
In 2011, exploration at Ridley Creek consisted of silt and rock sampling, a 3D IP survey and a total of 415.4 metres of drilling in 10 holes. Drilling on the RC zone revealed that the tungsten-bearing skarn mineralization continues beneath an overlying biotite schist and that the RC zone comprises a gently dipping, tabular shaped, calc-silicate unit varying from 4 to over 40 metres in thickness. The calc-silicate unit has been mapped at surface from the BN (MINFILE 093A 260) zone to the south, through the RC zone to the BK (MINFILE 093A 261) zone to the north over a distance of approximately 2.5 kilometres. Seven of the 10 holes intersected encouraging tungsten values, as well as anomalous zinc and indium. Highlights of the program include drillhole F11-07, which assayed 9.60 per cent tungsten trioxide, 3.64 per cent zinc and 19.2 grams per tonne indium over 0.4 metres (Assessment Report 32762).
In 2012, Happy Creek Minerals Ltd. completed a 29-hole diamond drilling program on the Fox property. Nineteen of the holes were targeting the Ridley Creek showing, and the best results include F12-18, which returned 24.7 metres of 0.68 per cent tungsten trioxide starting at 18 metres depth. This includes 1 metre grading 9.08 per cent tungsten trioxide, 0.61 per cent zinc and 4.6 grams per tonne indium (Press Release, Happy Creek Minerals Ltd., November 14, 2012).
In 2013, Happy Creek Minerals completed 21 diamond drill holes, totalling 1371.4 metres, and collected an approximately 800-kilogram bulk rock sample for metallurgical testing from the RC zone. Drilling is reported to have expanded and to have confirmed the continuity of the RC zone with the western most hole (F13-19) yielding 1.19 per cent tungsten tri-oxide over 26.3 metres, including 4.625 per cent tungsten tri-oxide over 3.66 metres (Gruenwald, W., Desautels, P. (2016-04-15): NI 43-101 Technical Report Resource Estimate of the Fox Property, Ridley Creek Zone).
In 2014, Happy Creek Minerals conducted a program of geological mapping on the western side of Deception Mountain which identified similar geology and tungsten-bearing calc-silicates and intrusive.
In 2015, Happy Creek Minerals completed a program of airborne magnetic and radiometric surveys, soil sampling, prospecting and geological mapping. Six diamond drill holes, totalling 1500 metres, were also completed on the Creek zone near the east end of the Nightcrawler (MINFILE 093A 258) zone. In addition, an approximate 500-kilogram bulk sample was collected from the face of the RC zone for metallurgical testing.
A resource estimate for the RC zone, using a 0.1 per cent tungsten tri-oxide cut-off, was also reported at this time with an indicated resource of 505,000 tonnes grading 0.468 per cent tungsten tri-oxide with an additional inferred resource of 280,000 tonnes grading 0.456 per cent tungsten tri-oxide (Gruenwald, W., Desautels, P. (2016-04-15): NI 43-101 Technical Report Resource Estimate of the Fox Property, Ridley Creek Zone).
In 2016, Happy Creek Minerals completed a program of trail construction, soil sampling, surface chip and channel sampling in 11 trenches, rock sampling, geological mapping and 28 diamond drill holes, totalling 2330 metres, on the BN, BK and RC zones. Ten holes were completed on the RC zone. Sampling of the trenches yielded from 1.53 per cent tungsten trio-oxide over 3.5 metre to 1.25 per cent tungsten tri-oxide over 5.0 metres, while drill holes F16-03 and F-16-09, located at the north and south west ends of the Ridley Creek deposit, yielded 1.14 and 0.52 per cent tungsten tri-oxide over 8.45 and 3.0 metres, respectively. (Desautels, P. (2017-03-10): NI 43-101 Resource Update for the RC Zone and Maiden Resource Estimate for the BN Zone of the Fox Tungsten Project).
In early 2017, Happy Creek Minerals released an updated mineral resource estimate, using a greater than 0.2 per cent tungsten tri-oxide cut-off grade, with a total indicated resource for the RC zone of 486,000 tonnes grading 0.818 per cent tungsten tri-oxide and a total inferred resource for the RC and BN zones of 361,000 tonnes grading 1.568 per cent tungsten tri-oxide (Desautels, P. (2017-03-10): NI 43-101 Resource Update for the RC Zone and Maiden Resource Estimate for the BN Zone of the Fox Tungsten Project).
In 2017, Happy Creek Minerals completed a further 66 diamond drill holes, totalling 6983 metres, on the Fox property along with prospecting, geological mapping and hand trenching. Mapping by ARC Geoscience Group identified and traced five separate calc-silicate layers each of which was found to contain scheelite. Layer no. 4 is the main layer hosting the BN, RC and BK zones, and layers no. 1 to 3 were found stratigraphically above this layer. These layers remain untested by drilling. Prospecting located a number of new outcrops containing scheelite along strike to the north and south of the RC zone. Hand-trenching was performed in the area south of the RC zone and returned positive results including 3.3 metres yielding 0.91 per cent tungsten tri-oxide, 0.35 metre of 1.32 per cent tungsten tri-oxide and 0.7 metre of 0.52 per cent tungsten tri-oxide, which all remain open in width (Desautels, P. (2018-02-27): NI 43-101 Resource Update for the RC and BN Zones and Maiden Resource Estimate for the BK Zone of the Fox Tungsten Project). These results confirm potential for mineralization to connect at or near-surface between the RC and BN zones.
In early 2018, Happy Creek Minerals released an updated mineral resource estimate, using a greater than 0.175 per cent tungsten tri-oxide cut-off grade, with a total indicated resource for the RC zone of 582,400 tonnes grading 0.826 per cent tungsten tri-oxide and a total inferred resource for the RC, BN and BK zones of 565,400 tonnes grading 1.231 per cent tungsten tri-oxide (Desautels, P. (2018-02-27): NI 43-101 Resource Update for the RC and BN Zones and Maiden Resource Estimate for the BK Zone of the Fox Tungsten Project).
