The Mount Dunn prospect is situated on a north trending saddle on the northeast spur of Mt. Dunn, midway between the east flowing King and Fewright Creeks about 5 kilometres west of the Unuk River.
The Mount Dunn prospect is part of a copper-gold porphyry system within the 170 to 300 metre wide Jurassic to Tertiary Hawlison Monzonite (Evan dike). Metallis Resources describes the mineralized section of the dike the Cliff-Nina corridor, with the Cliff (Priam 1) prospect at the south end and the Nina just south of the King prospect (104B 522). Drilling in 2018 is reported to have confirmed the continuity of copper-gold grades along the corridor, which extends over a strike-length of 4 kilometres (the Cliff-Nina corridor) - the southernmost portion of the 7.5 kilometre long Hawilson monzonite (Evan dike). The Cliff-Nina corridor is identified as a unique porphyry system with three distinct styles of copper-gold mineralization.
Significant alteration and mineralization is confined to equigranular monzonite of the Hawlison Monzonite (Evan Dike) which is variably sericitized, chloritized and silicified. Sulphide-poor, centimetre-scale, sheeted or stockwork quartz veins and stringers are present locally in each style of alteration. A few percent pyrite forms fine-grained disseminations or fracture fillings in altered rock. Chalcopyrite forms even finer-grained disseminations. Molybdenite is rare and irregularly distributed, noted in samples both rich and poor in copper and gold. Alteration outside the monzonite is limited to weak chloritization or sericitization and a few percent pyrite. The bulk of copper and gold mineralization in the prospect is hosted within three coherent zones of moderate to strong sericitization.
The property is underlain by a sequence of andesitic to rhyolitic volcanics of the Jurassic Hazelton Group that are intruded by a monzonite stock. The volcanic rocks vary in composition from Hazelton Group lithic and crystal lithic tuffs to Lower Jurassic Hazelton Group breccias and andesitic flows of the Unuk River Formation. The southeast part of the property is underlain by Upper Triassic Stuhini Group sediments comprised mainly of interbedded argillites, siltstones and carbonates that have been faulted to their present position. Regional metamorphism is of lower greenschist facies with significant epidotization in the andesites, agglomerates and flow breccias west of the intrusive.
The intrusion is comprised of a light green-grey fine to medium-grained monzonite and is described as a "high level", vertically tabular monzonite body that has apparently been block faulted up into volcanic sequence. It varies from 150 to 350 metres in width and appears to be continuous in a north-south direction for about 6 kilometres.
Sericite is the primary alteration mineral with propylitic assemblages of chlorite and calcite ubiquitous throughout the intrusive. Based on the degree of alteration, the intrusive has been subdivided as follows: hornblende monzonite, sericitized monzonite and felsitized monzonite. The hornblende monzonite is characterized by the presence of chloritized hornblende, lightly sericitized and suassuritized feldspars with minor calcite, pyrite, scattered chalcopyrite and malachite staining.
The sericitized monzonite is highly altered with abundant sericite and carbonate, plus/minus pyrite. This phase of the intrusive is highly fractured and hosts a mineralized quartz stockwork. Copper mineralization is present within the quartz veins and within the host rock at a ratio of pyrite to chalcopyrite of less than 2 to 1.
The altered intrusive is rusty weathered on surface and is frequently soft and crumbly due to extensive leaching. The phyllic alteration assemblage consists of sericite, pyrite, probable kaolin and remnant malachite. The felsitized intrusive, while being widespread, is particularly striking in a rusty band about 30 metres wide along the western side of the intrusive.
Copper mineralization in the form of chalcopyrite, malachite and azurite is widespread. Chalcopyrite is found most concentrated in and associated with quartz stockworks within the sericitized monzonite. In 1976, a 3.4 metre chip sample from this zone assayed 0.34 per cent copper, 0.0003 per cent molybdenum, 0.82 gram per tonne gold, and 2.05 grams per tonne silver. Two other chip samples, one 8.2 metres and the other 10.6 metres in length assayed 0.25 per cent copper, 0.55 gram per tonne gold, 0.34 gram per tonne silver and 0.87 per cent copper, 1.85 grams per tonne gold, 2.05 grams per tonne silver respectively (Assessment Report 6234).
Significant molybdenum mineralization was encountered in only one location. In 1976, a grab sample assayed 1.07 per cent copper and 0.19 per cent molybdenum.
An NQ drillhole drilled by Paget Resources in 2009 intersected 205.02 metres grading 0.159 per cent copper and 0.208 gram per tonne gold (Assessment Report 31245).
Significant sphalerite was found in one locality within the contact zone of the monzonite intrusion. Refer to Eric 2 (104B 152).
Geological mapping, drill core logging and assays have revealed that the Hawilson monzonite was intruded as north-south trending stocks and dikes, with porphyry copper-gold systems preserved at shallow levels. Drilling at the southern portion of the Hawilson Monzonite, referred to as the Cliff porphyry system (104B 620) to Nina (104B New), intersected multiple porphyry intrusions, and igneous and hydrothermal breccias followed by intense potassic and sericitic alteration. All 6 of the 2018 drill holes in the Cliff zone intersected extensive intervals of well-mineralized alteration zones, multi-generational veins, and copper-sulphides. The Cliff-Nina porphyry corridor, extends over a strike-length of 4 kilometres, at the southern end of the 7.5 kilometre-long Hawilson monzonite. The Cliff-Nina corridor is identified as a unique porphyry system with three distinct styles of copper-gold mineralization. This corridor encompasses the Mount Dunn prospect.
In the late 1960s, prospectors optioned the Evan prospect to Skyline Resources Ltd. but only physical work was recorded for assessment and the claims lapsed in 1973.
In 1974, Great Plains Development Company staked the Evan prospect and in 1975 and 1976, collected soils on a 120 by 120 metre grid over the broad ridge-top between King and Fewright Creeks grid (Assessment Report 5616, 6234). The sampling defined a semi-continuous 200 to 300 metre wide copper-molybdenum soil geochemical anomaly (greater than 180 parts per million copper, greater than 7 parts per million molybdenum), confined to a northerly-trending monzonite dike (the “Evan Dike”). The soil anomaly measured 2000 metres long, remaining open to the south. In 1976, Great Plains carried out mapping and several geophysical surveys (induced polarization, gamma ray spectrometry and magnetics). The IP survey indicated “an encouraging trend towards higher total sulphide, greater width and greater depth of mineralization in the southern part” of the grid. Great Plains did continuous chip sampling of two outcrops; they reported 0.60 per cent copper and 1.28 grams per tonne gold across 18.9 metres from. Great Plains also staked the Cole prospect, north of King Creek, and carried out a single day’s work on it; they were rewarded by a soil sample with 2120 parts per million copper. Great Plains recorded no further work and allowed their claims over the Evan prospect to lapse sometime between 1983 and 1986.
In 1980, Du Pont of Canada Exploration Limited staked the Cole prospect on the basis of anomalous heavy mineral results from a regional stream sediment survey. The following year, they took reconnaissance silt and soil samples and followed up with a soil/VLF/magnetics grid over the Cole prospect on the ridge-top between King and Terwilligen creeks. Du Pont’s geochemical sampling showed a 100 by 600 metre north-south copper-gold soil anomaly (greater than 250 parts per million copper, greater than 100 parts per billion gold) over the ridge-top. A line of soil samples beside Gossan Creek extended this anomaly a further 700 metres to the south; the anomaly remained open to the north and south. Du Pont personnel found a massive pyrite boulder in Gossan Creek with 7.1 grams per tonne gold but did not find significant mineralization in outcrop grid (Assessment Report 10474).
Placer Development Limited and Skyline Exploration Limited optioned Du Pont’s Cole claim in 1983 and carried out limited geochemical sampling that summer. Placer/Skyline’s work fleshed out Du Pont’s copper-gold soil anomaly on the Cole prospect and revealed elevated gold, silver, arsenic, zinc in isolated soils 500 metres west of Cole Lake grid (Assessment Report 11673).
In 1986 and 1987, Crest Resources Ltd. re-staked the Evan (King claims) and Cole (Consoat claim) prospects and carried out limited prospecting and geochemical sampling of the lower Gossan Creek area from a camp on King Creek (Assessment Report 16316).
In 1988, Cominco carried out 35 man days of mapping and geochemical sampling on the King and Consoat claims, focusing at lower elevations in the King Creek valley (Assessment Report 18614). Their mapping showed a major north-south fault (the “Adam Fault”) running up Gossan Creek; contour soil lines were anomalous in all metals within 50 metres of the fault and down to background levels within 200 metres of the fault. Cominco reported massive pyrite lenses and veinlets within argillaceous siltstone in the vicinity of the fault with up to 9500 ppb gold.
In December 1988, Winslow Gold Corp., who had staked their Priam claims southwest of Crest’s King claims, commissioned an airborne geophysical survey which extended north as far as King Creek and covered the Evan prospect (Assessment Report 19707). The Evan prospect area had just one weak conductor and background apparent resistivity, but the magnetic survey showed a sharp change from low magnetic relief east of the Evan dike to high relief to the west. In 1989, Winslow did limited prospecting and geochemical sampling over their claims, with the most promising results from the Priam Creek area. They mapped altered and mineralized “quartz diorite” (monzonite) south almost to Fewright Creek, extending the probable extent of the Evan dike and prospect by 1000 metres to the south. Winslow’s best grab sample from the Evan dike yielded 1.86 per cent copper and 4326 grams per tonne gold.
In 1989, Corptech Industries Inc optioned the King and Consoat claims from Crest Resources and carried out a helicopter-borne VLF/magnetic survey over them (Assessment Report 18987). They established a new soil grid over the Evan prospect, which confirmed Great Plains’ copper-molybdenum soil geochemical anomaly and revealed a coincident, but slightly narrower, greater than 100 ppb gold soil anomaly (Assessment Report 19269). They surveyed three reconnaissance IP lines across the Evan prospect and another over the Cole prospect. Although ground contact was difficult in the Evan zone due to sandy talus, the survey indicated two zones of high chargeability (greater than 20 ms) near the eastern and western limits of the lines. Corptech drilled three holes to test the western contact of the monzonite in an area of gold-bearing rock and soil samples and the western IP anomaly. The three holes cut pyritic, silicified monzonite. The holes were entirely split and sampled but detailed assay data has been lost; the best reported intersection averaged 604 parts per billion gold over 14.5 metres (as reported in Assessment Report 27130). The 1989 core is in good condition and cross-stacked near the drill area; the drill collars were surveyed by GPS in 2002.
The King and Consoat claims were allowed to lapse in 1994. They were restaked in 1994 as part of a larger property (the King property), but no further work was reported on the western part of the claim that contained the Mount Dunn (Evan) prospect (104B 079) and the Cole showing (104B 209). These claims lapsed in 1999 (Assessment Report 24075).
In 2002 Rimfire Minerals completed a program of rock and soil geochemical sampling collecting 117 rock and 79 soil samples (Assessment Report 27130). This work occurred on the Mount Dunn (Evan) prospect (104B 079) and the Cole showing (104B 209) areas.
In 2007, Paget Resources collected 16 rock samples on their Dunn Property (Assessment Report 29359).
In 2009 Paget drilled 5 NQ holes totalling 1586.7 metres (Assessment Report 31245). All drill holes intersected broad zones of low-grade gold and copper mineralization. Mineralization is associated with a dominant assemblage of silica-pyrite to silica-sericite (-chlorite)-pyrite alteration. Several phases of monzonite were intersected as well as monzonite clast breccias, especially in MD09-01 and MD09-02. Drill hole MD09-05 was the only drill hole to penetrate the monzonite contact and finished the hole in Stuhini Group mudstone-siltstone-sandstone west of the intrusion. Higher gold values with low copper were encountered at depth in this drill hole, associated with chlorite stringers and epidote. Moderately to strongly silicified monzonite occurs in scattered zones along the Evan dike, mainly within the sericitized areas. All holes intersected significant intervals of anomalous copper-gold mineralization, ranging in length from 74.5 to 336.5 metres with the best grade coming from the southern lowest elevation drill hole MD09-01 that assayed 0.23 per cent copper and 0.28 gram per tonne gold over 80.1 metres from 242.0 to 322.1 metres down the hole (Metallis Resources Press Release, Nov. 20, 2009). At the southern end of the system, rock chip sampling of outcrops below the 650-metre elevation yielded even higher gold and copper. The 2009 drilling indicates a gradual increase in copper and gold grades below the 1000-metre elevation and that better grade may occur at depth and to the south along the 1.5-kilometre part of the mineralized porphyry that remains untested.
In 2010, two float samples were collected beneath mineralized zones at the Cliff showing (104B producing assay results of 0.55 per cent copper, 1.3 grams per tonne gold, and 0.57 per cent copper, 0.8 grams per tonne (Ruks, 2010 (as reported in Assessment Report 34299)). See the Cliff showing (104B 620) for related results.
In 2013, Metallis Resources commissioned a 210 line-kilometre airborne geophysical (VTEM, magnetics and radiometrics) survey over a portion of the Kirkham property. A number of TEM anomalous zones are identified across the property. A major radiometric anomaly zone and several radiometric anomaly trends are observed across the block. The major radiometric anomalous zone in the western side of the block is thought to be a granitoid formation. Flight lines and results are shown to cover Mount Dunn (104B 079), Eric 2 (104B 152), Cole (104B 209), Achilles (104B 480) and King (104B 522) (Assessment Report 34299). Mineral occurrence Mount Dunn, Eric 2, Cole and King were sold to Metallis by previous owners Paget Resource. Metallis acquired Achilles from John Bot in June 2014.
In 2014, Metallis Resources collected 40 rock samples, mostly from the King Anomaly area (104B 522) between Nettle and Devils Creek. A total of 81 soil samples including three duplicates were collected.
In 2015, Metallis Resources conducted an exploration program on its Kirkham-Mount Dunn claims. Prospecting and chip sampling on the Cliff prospect (104B 620) was completed to follow up on rock sampling from 1989 and 2010 that produced anomalous gold and copper values (Assessment Report 35930).
In 2016, the company engaged Geotech Ltd. to conduct a VTEM/magnetic/radiometric survey over a 6,000-hectare portion of the property, not surveyed in 2013.
The 2016 survey identified four anomalies, which continue several hundred metres below the surface: Fewright Creek - features an arcuate resistivity and magnetic anomaly surrounding a magnetic low. A small felsic plug has been mapped within this target. A large gossan occurs on the western side of the target. King East - comprises large coincident magnetic and resistivity anomalies. Numerous gold-bearing veins and several small felsic stocks have been mapped on the southern part of this target: North and South Terwilligen - also characterized by coincident magnetic and resistivity anomalies.
The 2016 survey confirmed a fifth anomaly, a linear, very strong coincident resistivity and magnetic anomaly (King), originally identified by the 2013 survey. See the Metallis website to see an image showing the above 5 anomalies (http://metallisresources.com/).
On January 1, 2017, Metallis Resources Inc. released the results of a second airborne survey conducted in 2016 on the company's Kirkham property, which covers the Mount Dunn occurrences (Press Release, January 24, 2017). The combined 2013 and 2016 airborne survey covered the MINFILE documented occurrences: Mount Dunn (104B 079), Eric 2 (104B 152), Cole (104B 209), King (104B 522), Achilles (104B 480), Regent (104B 554) and Priam 1 (Cliff) (104B 620).
In 2017, Metallis Resources carried out a comprehensive exploration and drilling program focused on porphyry copper-gold mineralization in the Cliff target, shear-vein gold in the King prospect and magmatic nickel-copper sulphide mineralization in the Thunder North grass roots target. Metallis drilled 1 hole on the King prospect with no significant economic mineralization found. A total of 42 surface samples including 29 selective and 13 continuous rock-chip samples were collected for analysis on the greater Kirkham property.
The 2018 exploration program at the Cliff (104B 620) and Nina targets comprised 7 deep diamond drill holes totaling 3,406 metres, yielding intervals of significant gold-rich mineralization. The drilling assays confirmed the continuity of copper-gold grades along the Cliff-Nina porphyry corridor, extended over a strike-length of 4 kilometres, at the southern end of the 7.5 kilometre long Hawilson monzonite.
The 2019 diamond drill program highlights confirmed a 3km long porphyry system of near surface bulk-tonnage style copper-gold mineralization between the Cliff and Miles zones. Gold-rich mineralization in KH19-27 correlates with massive sulphide veins along syn-mineral conjugate faults and breccias. Interpretation of the updated 3D geological modelling has revealed two sub-parallel zones of copper-gold mineralization striking N15°E and dips ~70° to the east leaving a substantial gap of untested area open laterally and vertically (Metallis PR Feb 20, 2020).
The 2020 diamond drill program was designed to test the north-south extension and depth potential of the 4 km long gold-rich Cliff Porphyry System, which forms part of the larger 7.5 kilometre Hawilson Monzonite porphyry trend. A total of 3,820 metres were drilled in 5 holes spread out from the Cliff to the Nina areas. All five drill holes intersected broad intercepts of sulphide mineralization and pervasive silicification, attributed to higher gold grades within the Porphyry and surrounding calcareous siltstone units. Significantly, the altered and mineralized zone has now been traced over a vertical extent of one kilometre. (Metallis PR Nov 16, 2020).
See Cliff (104B 620) for further details.