Trachyte, basalt and rhyolite of the Miocene Pliocene Hart Peak Volcanics are conformably overlain by alkaline basalt flows of the Miocene-Pleistocene Level Mountain Group. To the west, are shale, siltstone and sandstone of the Lower Jurassic Takwahoni Formation.
The Heart Peaks basalt is part of an inferred 030 degree trending line of centres which includes Mount Edziza. Locally, trachyte domes, with associated late phreatic explosion breccias and vein mineralization, lie along a suspected old north-northeast trending fracture system. The geological model for exploration at Heart Peaks is a low sulphidation epithermal system associated with felsic volcanic rocks.
Three styles of alteration occur. Pervasive silicified zones in the trachyte and breccia are the main hosts to the mineralized veins. The silicified trachytes contain rozenite, melanterite, scorodite and jarosite. Widespread argillic alteration with pyrophyllite, centered in the areas with phreatic breccias, and affecting all rhyolitic units. Minerals resulting from argillation and opalization include illite, kaolinite, tridymite and grey opal. Alunite has been identified visually as veins in argillic alteration in two locations in Camp Creek.
Mineralization, associated with banded and/or vuggy quartz and rare amethyst veins, occurs along a north to north-east trend and includes, from south to north for 2 kilometres, the Top, Quartz Hill, Steep, End and Mogul zones. With the exception of the Top Zone, the quartz veining is intimately associated with the phreatic explosion breccias, cutting either it or adjacent silicified trachytes. Precious metals occur in quartz veins, silicified trachytes and open spaces. Pyrite is locally abundant and arsenopyrite is rare. Minor stibnite-opal veining occurs near the Mogul Zone.
The Top Zone covers a 100 by 200 metre area of intensely silicified trachyte with low sulphidation cross-cutting banded and vuggy quartz-adularia and minor amethyst veins. Visible ruby silver (pyrargyrite or proustite) occurs as disseminations in very fine-grained clay layers within well-banded quartz veins up to 1 metre in width. Vein directions are variable and difficult to determine but generally appear to trend 250-275 degree/75-85 degrees north. Vein textures are indicative of high levels in an epithermal system. At the Top Zone the veins have outer edges composed of primary banded, crustiform to coliform and cockade layers of grey to white chalcedonic quartz, pink to cream adularia and black, dull to shiny sulphide minerals, likely pyrite, tetrahedite-tennantite and acanthite. Internal to the banded vein are replacements of open-space filling features, now entirely quartz or rarely adularia. Important textures include lattice-bladed quartz after calcite and lesser parallel-bladed quartz (Blackwell, 2011 (as reported in Assessment Report 33664)). Maximum values previously reported from grab samples include up to 30.9 grams per tonne gold (Assessment Report 12141.) and 1408 grams per tonne silver (Schroeter, 1985 (MINFILE)). Work in 2011 by Colorado returned assay results up to 31.6 grams per tonne gold and 4282 grams per tonne silver from mineralized quartz vein samples. The corridor defined by the veins is up to 150 metres. A grab sample assayed 2.74 grams per tonne gold and 1345 grams per tonne silver (Assessment Report 12141).
The Quartz Hill Zone consists of open space filling and coarsely crystalline quartz veins hosted by polymictic breccias and silicified trachytes. The veins form a set of subparallel veins striking 150 to 165 degrees north. At Quartz Hill most exposed veins have narrow outer selvages of primary saccharoidal quartz with internal domains of vuggy to drusy prismatic quartz, adularia and possible barite. The internal quartz is crystalline, zoned, comb-like (perpendicular to the walls of the vein) and often displays terminated crystal faces. Adularia is similarly crystalline. Replacement of pre-existing calcite or barite is manifest as parallel and ghost-bladed textures with some lattice-bladed textures, though ghost-like. Many veins at Quartz Hill are marked by varying amounts of white to grey chalcedonic quartz which fills remaining open spaces in domains of bladed quartz and zoned crystalline quartz. Many of the veins at Quartz Hill are not in pristine condition, instead having been flooded and replaced by chalcedonic, low temperature silica. Those that are not replaced are relatively simple, open-space filling quartz veins. Quartz Hill may represent a late phase or be located peripheral to better mineralization (Blackwell, 2011 (as reported in Assessment Report 33664)). An historic grab sample assayed 1.4 grams per tonne gold, 502 grams per tonne silver and 0.49 per cent arsenic (Fieldwork 1984). In 1984 diamond drilling of the Quartz Hill zone assayed 0.481 grams per tonne gold over 110.3 metres from 24.4 to 134.7 metres depth in hole 84-4, indicating a bulk tonnage potential for this zone. 2011 chip sampling confirms the bulk tonnage potential with samples grading 0.74 gram per tonne gold over 10 metres width (Assessment Report 32535).
The Steep Zone is hosted by pyritic breccia and blocks of trachyte. Quartz veins up to one metre wide trend north-northeast and north-northwest and exhibit platy replacement and cockscomb textures, with large (5 centimetre) euhedral quartz crystals. Preliminary mapping in 2011 of this area suggests a strong element of continuity with the Quartz Hill – Top Zone areas, as seen by quartz and manganese-bearing structures which line up through these three areas. This identifies a total target area in excess of 1000 metres long, 150 metres wide and approximately 300 metres high (Blackwell, 2011). Maximum historically reported values are 5.0 grams per tonne gold and 84.0 grams per tonne silver over 2 metres (Assessment Report 9859).
The Mogul Zone contains several white to black, massive to drusy quartz veins within siliceous rhyolite-trachyte breccia. The breccia consists of kaolinized trachyte, trachyte, rhyolite, shale and chert fragments, and abundant disseminated pyrite. Results include 9.9 grams per tonne gold and 17.5 grams per tonne silver from a 24 centimetre channel sample (Assessment Report 9859) and 5.4 grams per tonne gold 23.0 grams per tonne silver from a 2 metre chip sample (Assessment Report 12141). Re-sampling in 2011 of historic diamond drill hole 87-1 returned 60.5 metres grading 0.41 gram per tonne gold (from 33.5 to 94.0 metres), indicating a bulk tonnage potential for this zone. Grab sample taken in 2015 yielded a maximum of 140.3 grams per tonne gold and 2786.0 grams per tonne silver (News Release, Colorado Resources, November 3, 2015).
In 2011 the Colorado Resources discovered a new zone of gold mineralization 1,200 metres east of the Top Zone called the Midas Zone. At the Midas Zone, gold mineralization has been identified within an east-west trending quartz vein zone which, based on rubble fragments and soil-talus fines geochemistry, has a strike length of at least 200 metres. The surface on-strike expression of this vein system is obscured to the east beneath surficial cover. Three of only five samples collected from the Midas zone in 2011 returned values of 4.7 grams per tonne, 8.5 grams per tonne and 10.4 grams per tonne gold, with 23 grams per tonne, 60 grams per tonne and 32 grams per tonne silver, respectively (Assessment Report 32535). In 2012, a grab sample from the Midas zone yielded 126 grams per tonne gold and 158 grams per tonne silver (Assessment Report 33664). The Midas zone, which has returned the highest gold-in-rock samples on the property to date, is defined by a 200-metre-by-50-metre, east-west-trending gold and silver soil geochemical anomaly. This anomaly is contained within a 200-metre-by-five-metre-to-100-metre-widearsenic anomaly.
The alteration and mineralization likely occurred at a very high level within an epithermal system.
During 1980, J.C. Stephen Exploration Ltd. located rusty weathered quartz veins within siliceous and pyritic rhyolites and trachyte breccias in Hearts Peak area. Analysis of samples from this area indicated anomalous levels of gold. On behalf of a syndicate (Newmont Canada, Lornex and, J.C. Stephen) the Hart 1-6 claims were located over the Hearts Peak area.
During 1981, the syndicate completed a geological and geochemical program over the project area. The property was gridded, mapped and 339 rock, soil, and talus samples were collected for geochemical analyses. Values of up to 514 grams per tonne silver silver and 6.5 grams per tonne gold were recorded. During 1982, the geological and geochemical programs were continued along with limited trenching and sampling of some of the quartz veins. No new significant mineralization was detected.
In 1983, Lornex opted out of the syndicate and a new partner, Kerr Addison Mines Ltd., joined the group. During 1983, 49 line kilometres of grid were placed on the property to serve as survey control for the continued exploration. A VLF EM-16 geophysical survey was completed over the property Grid. Geological mapping and prospecting was continued through the 1983 season. During 1983, 519 talus fines and soil samples were collected and analyzed and 139 rock chip samples were collected and assayed.
During 1984 Kerr Addison on behalf of the syndicate completed a diamond drill program. Eight wide spaced shallow drill holes were completed in three areas for a total of 1972.3 metres of NQ drilling. No economic levels of gold and silver mineralization were encountered during the 1984 drilling.
No exploration work was done at the Hearts Peak property between the 1984 drilling and the work by US Diamond Corp in 1996. In 1996, the property was under option to US Diamond Corp from Inukshuk Capital Ltd. The exploration program on the Sheslay 1-7 and Free Mineral Claims, (Heart Peaks property) consisted geological mapping, minor rock sampling, drilling two cored holes and thin section examination of samples from drill core. Heavy mineral concentrates and silt samples were collected across and beyond the claim group. Soil sampling was done on two reconnaissance lines and IP test surveying was tried on three lines in the valley of Camp Creek. Drillhole 96-l was drilled to explore at depth the interpreted structural trend between Top and Steep Zones and Mogul Dome. It indicated phreatic breccias within 20 metres of the Takwahoni unconformity, basaltic and andesitic flows in the basal portion of the Heart Peaks, mineralized rhyolitic breccia below the unconformity, gold values of up to 0.79 grams per tonne gold with pyrite veinlets and minor quartz-calcite, and no altered or mineralized fault zones. Drillhole 96-2 was drilled to test the easterly exposure of the area with rhyolitic domes and siliceous sinter. Results were insignificant.
In 2011, work by Colorado Resources on the Heart Peaks Property consisted of prospecting, preliminary geological mapping and collection of 209 rock samples and 11 soil/silt samples. Historic drill core was re-logged and selectively sampled with the collection of 105 core samples for analysis. PIMA alteration studies were completed on 34 rock and 11 historic drill core samples. The 2011 exploration program was conducted in two campaigns. The first campaign included an airborne magnetic and electromagnetic survey (1100 kilometre) and prospecting program in July 2011, followed by a second prospecting and sampling program in August 2011. The airborne geophysical survey successfully demonstrated that the known mineralization at Heart Peaks is located within a 700 by 2500 metre resistivity feature that extends beyond the areas of known mineralization. Several additional, strong resistivity features occur on this large property and require additional follow up work. The ASTER analysis demonstrated that the known mineralization at Heart Peaks is associated with jarosite, quartz and kaolinite reflectance spectra. Rock grab sample results from the Top Zone reported assay values up to 31.6 grams per tonne gold and 4,282 grams per tonne silver (Assessment Report 32535). A second previously unknown zone – the Midas Zone, located 1.2 kilometres southeast of the Top Zone yielded grab sample values of 4.7 grams per tonne, 8.5 grams per tonne and 10.4 grams per tonne gold, with 23 grams per tonne, 60 grams per tonne and 32 grams per tonne silver, respectively (Assessment Report 32535).
Work by Colorado Resources in 2012 included the collection of 445 rock samples and 2474 soil samples. Following the field season SWIR (shortwave infrared) alteration studies were completed on 202 rock samples to examine the clay alteration mineralogy on the property. In September-October, 2012, 22.2 kilometres of line was cut, and 13 kilometres of an Induced Polarization (IP) survey was completed over the Midas, Top, Quartz Hill, and Steep Zones to assess mineralization potential of the underlying volcanic rocks. Soil sampling was focused on the central claims of the Heart Peaks Property (Heart 1 and Heart 2), infilling from previous exploration programs across the Midas, Bottom, Top, Quartz Hill, Steep, and Mogul zones. Additional soil sampling was completed to the immediate north and south of these areas. The 2012 soil sampling program identified several areas of significant gold-silver mineralization, and anomalous zones of Gold-pathfinder elements (arsenic, antimony, mercury) that require follow-up. The largest gold geochemical anomaly, defined by the 95th percentile (greater than 85 parts per billion) gold value, is 200 to 300 metres wide and extends north from the Top Zone for 1200 metres.
In 2015, the Hearts Peak property was under option to Centerra Gold Corp from Colorado Resources. Work in 2015 consisted of the collection of 250 soil samples, 150 rock samples and 4 silt samples; 13 kilometres of IP were completed on 6 lines. Geological mapping increased the coverage of 1:10000 scale from about 40 square kilometres to about 65 square kilometers while a drone survey provided detailed aerial photography over a 46 square kilometers area in the centre of the property. The current soil grid was extended for 500 metres east of the Midas Zone on ten 100 metre spaced lines while reconnaissance samples were collected on 5 lines to the north of the Mogul zone and on one line south of the Midas Zone. The programs showed that gold mineralization is focused along two lithologically and structurally defined corridors: the west-northwest-trending, two-kilometre-long Top-zone-to-Midas-zone corridor and the north-trending, four-kilometre-long corridor bounded by the Mogul East and Mogul West fault systems, which includes the Mogul, End, Steep and Crater zones.
Prospecting during the 2015 program focused on 3 areas; an area about 2 kilometres to the north of the Mogul Zone called the Caldera Zone, an area about 5 kilometres south of the Bottom Zone called the Lung Showing and an unnamed area about 1.2 kilometres to the southeast of the Midas Zone. No significant economic mineals were discovered but antimony and arsenic were locally anomalous at the Caldera zone.
In 2016, work by Centerra consisted of 1703 metres of diamond drilling in 10 holes in 3 separate zones (7 at Midas, 2 at Top, and 1 at End zones), 6.8-line kilometres of IP geophysical survey, a 500 by 1500 metre ground magnetic geophysical survey, and a small detailed mapping (and structural interpretation) program covered the Top, Midas, Mogul and End zones, and the collection of a total of 26 rock samples. The IP survey outlined several chargeability anomalies and the magnetic survey confirmed the west-northwest orientation at the Midas Zone. Diamond drilling of the IP target at the End Zone intersected abundant quartz-pyrite veinlets with no significant gold mineralization. Although several significant hydrothermal breccias zones were encountered in the drilling at the Midas Zone, gold grades were lower than anticipated and lower than gold grades encountered in previous surface sampling programs. Two holes drilled in 2016 tested quartz-adularia vein above the 1400 metre elevation mark. These holes intersected several quartz-adularia-sulphide veins ranging from 1 to 2 centimetres up to 50 centimetres in width. Hole HP16-07 assayed 0.94 gram per tonne gold over 2.1 metres; 5.3 metres of silica-pyrite matrix-supported hydrothermal breccia in HP16-07 assayed 0.63 gram per tonne gold over 2.0 metres (Assessment Report 36329).
