Judy Baker is President and CEO of Argo Gold and Delio Tortosa is a geological consultant.
After a 25-year lag in gold exploration in the Uchi Gold Camp, Argo Gold Inc. has been reviving exploration discovery interest in the ‘shadow of the headframe’ south of the historical Uchi Gold Mine with its high-grade Uchi Gold Project in Northwestern Ontario.
During the mid-1930s to the early 1940s, four gold mines were developed by Uchi Mines Ltd. under the direction of Jack Hammel, a well known mine developer in the Red Lake area. The gold mines are in the southeast end of the Birch-Uchi Greenstone Belt, about 100 km east of the prolific Red Lake Greenstone Belt.
Argo Gold’s Uchi Gold Project of 22 square kilometers of 100% owned claims is the highly prospective, yet relatively unexplored ground immediately south and on trend with the historical mines.
In the 1930’s, several companies were amalgamated into a large property holding which became the Uchi Gold Mine Camp. A settlement was established near the main Uchi Mine shaft which included a hotel, school, post office, bank, curling rink, community hall and 15 dwellings providing housing for miners and their families.
Uchi Gold Mines Ltd. was later taken over by Little Long Lac Gold Mines Ltd., which became Lac Minerals Ltd., which was later purchased by Barrick Gold Corp. The mines on these patents underwent mine rehabilitation from 1996-1998 and have received limited exploration since the mines closed during the Second World War.
Notably, the rocks and geological structures associated with the Uchi Mines extend to the south onto Argo Gold’s Uchi Gold Property. During the early days of exploration in the 1930s, prospectors were able to identify significant prospects on the Barrick Gold patents to the north due to much better rock exposure, whereas companies exploring to the south had thicker overburden cover (1-3 m) and thus few outcrop prospects were identified.
Argo’s exploration approach is using modern tools and techniques to offset this limitation (geophysics, geochemistry including biochemistry, surface stripping, mapping and sampling).
In the early 1990’s, exploration on Argo Gold’s Uchi Gold Project was initiated by St. Jude Resources, and by persistent prospecting and utilizing various exploration methods, the Woco Vein was discovered near surface.
The narrow vein was stripped and sampled returning modest but good gold grades. With this information in hand, St. Jude initiated a drill program on the Woco Vein in 1993, which was designed to test the vein at shallow depths.
Chester Kuryliw, a well-known geologist, logged and sampled the core, and to his surprise noted that the vein increased in width up to two metres at greater depth and carried visible gold with assays of up to 1-3 ounces per ton gold.
A year later, a second drill program was completed which outlined a steeply plunging quartz lense or shoot with high-grade gold down to 150 metres. Argo Gold’s winter drill program in 2019 confirmed the historical discovery with drill intercepts including 132 grams per tonne gold over 1.8 metres.
In 2016, Argo Gold was founded to acquire high-grade gold projects in Northwestern Ontario and an extensive effort was made to look for suitable gold prospects. When we dug into the assessment files on Woco Gold, it became obvious that this was an excellent acquisition, and so with some persistence a deal was made with the private company and owner of the property (former President of St. Jude Resources).
Similarly, a separate deal was reached on the adjoining Northgate Gold situated several kilometres southwest of Woco and following a similar regional trend.
In 2018, Argo Gold continued to acquire ground in the camp with the acquisition of the Geisler Patents containing the known mineralized RainGold outcrop. Given the evidence of widespread gold mineralization at all known outcrop defining a materially mineralized gold corridor from the past-producing Uchi Mine to Woco and further southwest to Northgate, Argo Gold staked another 8.4 square kilometres along the mineralized Uchi corridor in 2018.
Argo Gold’s Uchi Gold Project now covers 5 kilometres of multiple mineralized trends made up of materially mineralized outcrop and confirmed high-grade gold mineralization to the current drilling depth of 200 metres.
In the Spring of 2017, Argo Gold raised financing to initiate exploration at all of its 100% owned gold projects including several gold project peripheral to Wesdome’s Eagle Mine in the Wawa area and in Northwestern Ontario, the Uchi Gold Project and the McVicar Lake Gold Project.
Exploration was carried out at the Uchi Gold Project by Argo Gold Team Geologist William Kerr. Early in the season the Woco Vein was cleared and sampled and the 1993 drill holes were located and probed. Later in the season – after acquisition of additional ground – Northgate Gold – to the southwest along the mineralized corridor – was cleared and sampled. Northgate Gold has wider shear-hosted gold mineralized quartz veins at surface.
The probe work at Woco was possible as most of the 1993-94 drill casing was still in place on the Woco and a Reflex crew was able to do a down-hole orientation survey. Although the core racks had collapsed and the writing on the plastic tags had faded after 25 years, the historical drill logs, assays, and downhole surveys were then incorporated into 3D modeling software.
From the 3D model, plans and sections we could see that the strike extension had not been tested and the Woco Vein was still open at depth. After some data compilation, a drilling plan was designed to test the core of the high-grade vein, the strike extensions, and depth extent to 200 metres.
With funding for a 2500 metres drill program, Argo Gold carried out a helicopter supported drill program in the Winter of 2019 at the Uchi Gold Project focused on the Woco Gold Vein, Northgate Gold and the Uchi Break – a zone 300 metres east of Woco consisting of fracturing, mineralization, veining, and shearing extending south/southwest from the historic mines to the north.
The initial drill hole at the Woco Vein targeted the historic high-grade mineralized zone and intersected a quartz vein almost two metres in length with well disseminated, fine-grained, visible gold containing 132 grams per tonne gold over 1.8 metres. This was the verification we needed for the historical drill holes with high grade gold values.
Drilling along strike confirmed that the mineralization occurs in shoots. A fan of two drill holes targeted the Woco Vein at 150 metre depth with some visible gold in the quartz, and the deeper hole intersected a wider altered zone in the hanging wall of the Woco vein. A fan of three drill holes was positioned to intersect the plunging shoot down to 200 metre depth. All of the three drill holes intersected the Woco vein with two drill holes showing visible gold.
Additional drilling is required to continue to determine the strike length, depth extent and high-grade controls of the Woco Vein and potential for a deep-seated feeder system.
Argo Gold also drill tested a geophysics anomaly associated with the Uchi Break, a structure closely associated with the historic Uchi Mines to the north. Several holes intersected the Uchi Break which varied from a zone of massive sulphide (mostly pyrrhotite and pyrite with anomalous gold 0.5 gm/t and manganese 0.6%) in the north, to a zone of metasediments with quartz veining and containing ductile shear zones, in the south.
Argo Gold also drilled the Northgate Gold intersecting a shear-hosted quartz vein system that was drilled by Northgate Exploration in 1959 after visible gold was identified in outcrop the 1930s and later. Argo Gold verified the presence of a gold mineralized shear-hosted vein system at Northgate Gold where all three drill holes intersected the vein system including intersecting 34 grams per tonne gold over half a metre.
In addition, the mineralized zone was extended 50 metres to the east-northeast for a total strike length of 250 metres. There are several historical drill hole intersections on this gold prospect from the late 1950’s (0.37 opt/3.3 ft; 0.27 opt/12.1 ft, 0.19 opt/ 4.8 ft), but little information is available from drilling the mid-1930’s.
Additional drilling is required to continue to determine the strike length, depth extent and high-grade controls of Northgate Gold and potential for a deep-seated feeder system.
Current exploration work involves a detailed biogeochemical sampling survey at the Uchi Gold Project. The program is designed to follow up on a Spring 2019 geochemical orientation survey which successfully identified known gold mineralization. The detailed geochemical survey will sample a 600 metre wide swath along five kilometres of the Uchi mineralized corridor. Approximately 1,100 samples will be collected on a 60 x 60 m diamond pattern.
There is minimal outcrop at the Uchi Gold Project which now consists of 22 square kilometres of mineral claims and identifying areas of anomalous gold mineralization under overburden will provide important information. Argo Gold does have very high quality AEM/AMAG geophysics coverage for the Uchi Gold Project which defines the mineralized Uchi Corridor and is useful in identifying crosscutting structures and lithologies that are potentially gold bearing.
The combination of geological and structural mapping at known outcrops, geophysics, and pending geochemical gold anomalies will be a powerful combination of information to advance exploration activities at Argo Gold’s Uchi Gold Project which covers five kilometres of multiple mineralized trends in the Uchi mineralization corridor.
Future exploration at the Uchi Gold Project will also focus on extending the depth of the high-grade Woco Vein, additional drilling along strike and at depth at Northgate Gold which also hosts up to one ounce per ton gold intercepts. Digital GIS and oriented optical borehole structural mapping tools are being evaluated to better understand high-grade structural controls.
The current Woco drilling along with the historical drill holes from the mid-1990’s has identified a steeply plunging lense (-70o NNE) of high-grade gold mineralization on a NNE trending, steeply west-dipping structure, which is still open at depth.
Closely spaced plunging shoots characterized the Uchi Gold Mine to the north is an encouraging trend that could assist with understanding the periodicity of high-grade shoots and lode vein systems at Argo Gold’s Uchi Gold Project. Several successful examples of mines in these types of high-grade gold settings are the Island Gold Mine, Alamos Gold, and the Eagle River Mine, Wesdome Mines, Wawa.
Exploration activity and staking has increased in the Red Lake and the Birch-Uchi Lake areas driven in part by Great Bear Resources’ Dixie Lake gold discovery and First Mining Gold’s continuing feasibility study on the Springpole Gold Deposit by New Mining Gold in the northern part of the Birch-Uchi Greenstone Belt.
Argo Gold’s exploration activity at the Uchi Gold Project in the south end of the Birch-Uchi Greenstone Belt has potential to lead the next wave of high-grade gold discoveries in the area.