Victoria Gold Corp.’s Dublin Gulch property is located in the Mayo mining district, central Yukon, approximately 85 kilometers north of Mayo and 370 kilometers due north of the territorial capital, Whitehorse.
Large-tonnage reduced intrusion-related gold systems associated with Cretaceous Tombstone and Mayo suite granodiorite intrusions and structurally-controlled high-grade gold-sulfide veins.
The Dublin Gulch property comprises the flagship Eagle gold deposit and multiple adjacent prospects at various stages of exploration. Mineralization at Eagle is characterized by sub-parallel, gold-bearing sheeted quartz vein arrays that developed proximal to the contact between the Cretaceous-age granitoid Dublin Gulch stock and surrounding metasedimentary country rock. The density and continuity of the vein sets make the gold deposit amenable to open-pit mining. The property has been explored by a series of owners and operators, initially for tungsten and subsequently for gold. Victoria Gold acquired the Property in June 2009 and commenced drilling and other exploration work that same year. Eagle currently reports an Indicated Resource of 4.8 million ounces gold and an Inferred Resource of 1.5 million ounces gold (Wardrop - 2011). Inclusive within the Indicated Resource is a Probable Mineral reserve of 91.6 Mt, with a diluted grade of 0.781 g/t Au for 2.3 M ounces of gold (Wardrop/Tetra Tech - 2012).
Geology and Mineralization
The Dublin Gulch property is located in the north-central part of the Selwyn Basin on the northern limb of the McQuesten Antiform. The area is underlain by Proterozoic to Lower Cambrian-age Hyland Group metasedimentary rocks intruded by the Cretaceous Dublin Gulch granodiorite stock. The stock is elongate in a northeast direction and measures approximately five kilometers in length and two kilometers in width. The Eagle gold deposit is localized at the narrowest exposed portion of the stock, near its known western limit (Figure 1).
The Dublin Gulch intrusion has a U-Pb age date of 94 ±0.3 Ma (zircon; Shelby et al, 2003) and is a member of the Tombstone plutonic suite. It is predominantly composed of equigranular biotite hornblende granodiorite with minor diorite and granite phases. A pronounced metamorphic aureole in the surrounding Hyland Group rocks hosts subordinate amounts of gold in veins and breccia near the intrusive contact.
Eagle is characterized as a reduced intrusion related gold system (RIRGS). Mineralization comprises sub-parallel quartz, quartz-sulfide and sulfide-only veins that are best-developed within the granodiorite proximal to both the hanging wall and footwall contacts. The veins are also well developed within embayments and narrow portions of the stock. Individual veins are typically composed of white or grey quartz with subordinate potassium feldspar and range in width from one millimeter to more than 10 centimeters. Veins typically strike between 060° and 085° and have a near-vertical dip, and vein sets form steeply north-dipping to near-vertical zones that are amenable to bulk mining. Mineralization occurs as elemental gold, both as isolated grains and most commonly in association with arsenopyrite, pyrite and pyrrhotite. Higher grades generally correlate with thicker veins and greater vein sulfide abundances.
POTATO HILLS TREND
The Potato Hills trend (PHT) is a >13 km-long belt of Au-As-Bi-Sb and Ag-Pb-Zn mineralization extending to the northeast and southwest of the Eagle deposit along the margins of the Dublin Gulch granodiorite stock and beyond (Figure 2). The trend hosts several gold prospects at various stages of exploration, all of which are expected to be accretive to the Eagle project, as well as the Rex and Peso silver targets. More advanced gold targets include Olive, Shamrock and Popeye. The PHT is approximately coincident with the regional scale Tombstone high strain zone associated with Jurassic-Cretaceous tectonics of the Cordillera, and the interaction of the Tombstone strain zone with the cooling host pluton is considered integral to the formation of gold mineralization at Dublin Gulch.
In contrast to Eagle-type mineralization, which is composed of vein arrays of thin, sub-parallel quartz and quartz-sulfide veins, mineralization along the PHT is generally characterized by a series of widely-spaced, structurally-controlled arsenopyrite-sulfosalt veins, distinct in both grade and style from the Eagle zone. Many of these veins were exploited historically and old shafts and adits can still be observed on the property. Mineralization in these veins is generally of a significantly higher tenor than in the quartz veins typically associated with Eagle-style mineralization, with visible gold observed in hand specimen and multi-ounce grades returned from grab samples. Silver grades exceeding 200 g/t Ag have been returned from grab samples along the PHT. Surface mapping and sampling, 2-3 km east of the Potato Hills, have also shown Au bearing samples in excess of 10 g/t Au (Table 1).
The Olive, Shamrock and Popeye zones, all of which are located between 2.5 km and 3.5 km northeast of Eagle, are the best examples of intersecting high-grade PHT-type veins and Eagle-style mineralization. Grab samples of thick arsenopyrite-scorodite-sulfosalt veins collected from Olive during the 2012 field season showed abundant disseminated visible gold and returned assays up to 189.5 g/t Au. 2010/2011 drilling in the Shamrock zone showed strong signatures of PHT mineralization, with grades of up to 118 g/t Au in restricted vein swarms. The PHT mineralization can commonly be seen cross-cutting and overprinting earlier Eagle-style mineralization, as well as reactivating and re-filling originally Eagle style veins resulting in significant gold endowment in areas of intersecting mineralization. Ongoing research into the metallogeny of the Dublin Gulch property suggests that PHT mineralization is most likely due to a second hydrothermal fluid event emanating from the Dublin Gulch granodiorite stock or from a deeper plutonic phase at depth.
Table 1. High-grade grab samples collected from the Potato Hills Trend
The Olive target is located 2.5 km from Victoria’s Eagle gold deposit and is the site of several historically exploited high-grade sulfide veins. The area was mined on a small scale from shallow shafts and adits at the turn of the last century and placer mining in creeks draining the area indicate gold-bearing host rocks. The Olive vein is located near the top of Olive gulch and consists of gold-bearing quartz-scorodite-arsenopyrite vein material. A 200 meter trench excavated and sampled in 1991 exposed a zone of quartz and quartz-arsenopyrite veins hosted in the Dublin Gulch granodiorite that averaged 1.2 g/t Au over 97.6 meters. Diamond drill hole 91-012C collared in the trench intersected 89.9m grading 1.08 g/t Au and drilling by Victoria Gold Corp in 2010 verified the gold mineralization (DG10-384C: 20.30 m grading 1.93 g/t gold (from 18.1 m to 38.4 m) plus 41.10 m grading 0.96 g/t gold (from 49.1 m to 90.2 m), Victoria Gold news release, November 17, 2010). Subsequent drilling in 2011 continued to intersect mineralization (22.83 meters averaging 0.72 g/t gold; hole DG11-466C, Victoria Gold news release, January 17, 2012).
In 2012 the company completed 11 diamond drill holes for 2996 m and carried out a reconnaissance surface mapping program. Best results of the 2012 surface sampling program (Figure 3) included 189.5 g/t Au, 64.0 g/t Au and 11.5 g/t Au (all grab samples) from arsenopyrite and scorodite-arsenopyrite veins in trench OLTR-09. Drilling at Olive targeted along-strike and down-dip extensions of gold mineralization identified in previous drilling and trenching campaigns and sub-surface expressions of outcropping high-grade veins identified during reconnaissance surface sampling conducted in the summer of 2012. Best results of the diamond drilling program included 26.50 m of 2.69 g/t Au, 1.9 m of 5.62 g/t Au, 1.3 m of 39.2 g/t Au, 6.4m of 3.12 g/t and 10.1m of 2.56 g/t Au (Table 2). The 2012 program adds to the historical work (Tables 3 and 4) and indicates that the Olive area has the potential to become Victoria’s next significant resource.
Table 2. Recent results from the 2012 diamond drilling program
Grade (g/t Au)
Width of holes DG12-528C – DG12-535C is reported as drilled and true widths have not been determined. DG12-528 did not intersect significant mineralization.
Table 3. Best results from the 2011 Olive diamond drilling program
Grade (g/t Au)
Apparent true widths of holes DG11-438, 443 and 448 are 90%; the apparent true width of hole DG11-445 is 50% of the intersection length. DG11-440C did not intersect significant mineralization.
Table 4. Best results of the 2010 Olive diamond drilling program.
Grade (g/t Au)
Width of holes is reported as drilled and true widths have not been determined
Shamrock and Popeye Prospects
Shamrock and Popeye are located approximately 3 km northeast of Eagle, and are host to high-grade quartz-arsenopyrite veins returning up to 24 g/t Au and 20 g/t Ag in diamond drill holes. Shamrock was mined on a small scale from numerous shallow shafts and adits at the turn of the last century. Popeye is a recent discovery by Victoria Gold and comprises a massive sulphide vein system in a detached, highly altered granodiorite cupola to the northwest of Olive. Exploration programs in 2010 and 2011 highlighted several thick mineralized intervals and high grade mineralization at both prospects (Table 5).
Table 5. Best results from regional exploration drilling at Shamrock and Popeye
Grade (g/t Au)
Apparent true widths of intersections at these targets are between 70 and 90% of the tabulated intersection length. Holes DG11-433C, DG11-434C, DG11-453C, DG11-461C, DG11-463C and DG11-465C at Shamrock did not cut significant mineralization.
The Steiner target area is located adjacent to the Eagle deposit approximately 1.2 km to the northwest. Mineralization at Steiner is geologically similar to Eagle and is a potential satellite deposit accretive to the main Eagle deposit. Exploration drilling in 2011 confirmed the presence of thick, low-grade intervals near surface at Steiner (Table 6).
Table 6. Best results from 2011 diamond drilling program at Steiner
Grade (g/t Au)
Apparent true width is approximately 70 % to 80 % of intersection lengths.
The road-accessible Rex and Peso silver veins are located approximately 5 km west of the Eagle deposit. The veins were discovered in the early 20th century and have been explored and exploited for silver since they were staked in 1912. Mineralization is primarily hosted in structurally controlled lead-silver sulfosalt veins that have returned grades up to 224 oz/ton Ag (7680 g/t Ag). Several veins have been exploited by underground mining methods, and a number of shafts and adits have been sunk in the area. Recent exploration by Victoria has confirmed the presences of thick, high-grade silver intervals, with best results from the 2011 diamond drilling program of 4.81 m of 259 g/t Ag and 0.45 m of > 10,000 g/t Ag.
Also of significant interest at Rex-Peso is the possibility of gold mineralization similar in style, and possibly additive to Eagle. Several operating placer mines (e.g. Secret Creek) have their headwaters in the Rex-Peso area, and stream sediment samples collected by the Geological Survey of Canada returned anomalous gold in Secret Creek, Gill Gulch and 15 Pup (Figure 4). Minor outcropping granodiorite is observed in the area, however airborne geophysics suggests the presence of a much larger buried intrusion (Figure 5) which may be of similar character to the Dublin Gulch stock and have the potential to host mineralization of similar calibre.
Lynx is an early-stage prospect helicopter-accessible project located approximately 9 km east southeast of Eagle and approximately 13 km northwest of the township of Elsa. A total of 2640 m of diamond drilling in 21 holes has been completed at Lynx, with all but one of those holes drilled during the 1997 and 2004 programs. Drilling has returned several narrow intersections with grades up to 28.5 g/t Au and several thicker, lower-grade intervals (Table 7). Mineralization identified to date appears to be concentrated along the contact between an igneous intrusion and surrounding country rock, similar to much of the mineralization elsewhere in the Potato Hills Trend. An interpretation of the diamond drilling and trenching completed to date suggests an east-west strike to mineralization (Figure 6) and limited soil sampling conducted to the east and west of the prospect suggests continuity of mineralization in both directions. Mineralization intersected in diamond drilling is open at depth and along strike to the east and west, and soil data indicate Au in soil > 30 ppb to the east and west of the prospect.
Table 7. Best results from diamond drilling at Lynx
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