The Keno Hill Silver District is in the central Yukon, which is characterized by subarctic continental climate with cold winters and warm summers. Annual precipitation averages 28 cm and half of this falls as snow, which starts to accumulate in October and remains until May or June. The landscape of the District is characterized by rolling hills and mountains with a relief of up to 1,600 m, the highest of which is Keno Hill at 1,975 m.
EXPLORATION
Mineralization in the District is of the polymetallic silver-lead-zinc vein type where multiple pulses of hydrothermal fluids or fluid boiling, probably related to repeated reactivation and breccia formation along the host fault structures, have formed a series of vein stages with differing mineral assemblages and textures. Supergene alteration may have further changed the nature of the mineralogy in the veins. Much of the supergene zone may have been removed due to glacial erosion. In general, common gangue minerals include (manganiferous) siderite and, to a lesser extent, quartz, and calcite. Silver predominantly occurs in argentiferous galena and argentiferous tetrahedrite (freibergite).
In some assemblages, silver is also found as native silver, in polybasite, stephanite, and pyrargyrite. Lead occurs in galena and zinc in sphalerite, which can be either an iron-rich or iron-poor variety. Other sulphides include pyrite, pyrrhotite, arsenopyrite, and chalcopyrite. The Keno Hill mining camp has long been recognized as a polymetallic silver-lead-zinc vein district with characteristics similar to other well-known mining districts in the world.
Alexco has been actively exploring and developing the KHSD since 2006 and exploration has become an essential part of our business and success. Our exploration geologists have made several significant discoveries including the Flame and Moth and Bermingham deposits that form the backbone of Keno Hill’s current mining operations.
In 2018, Al McOnie, Seymour Iles and Jared Chipman received the H.H. “Spud” Huestis Award for excellence in prospecting and mineral exploration for discovering and delineating more than 60 Moz of Ag in the Flame & Moth and Bermingham deposits at Keno Hill.
Alexco has been actively exploring and developing the Keno Hill Silver District (“KHSD”) since 2006 and exploration has become an essential part of our business and success
Alexco Published an Updated Version of Keno Hill Silver District’s Geological Map
In 2020, Alexco’s Al McOnie, Peter Read, and Seymour Iles, in conjunction with the Yukon Geological Service, prepared and published an updated version of the geological map of the Keno Hill Silver District.
The map is the culmination of a multi-year effort and significant investment by Alexco and details the stratigraphy, structure, and possible mechanisms for the deposition of mineralization in the District. Alexco, by virtue of an Agreement with the Government of Canada, is the custodian of the historic archive of the District’s mining and geologic data, which is housed in Elsa and has allbeen copied to a digital medium, much of it to 3D formats. The map comprised for the first time a consolidated GIS compilation of 32 former United Keno Hill Mines (UKHM) exploration map sheets originally recorded in a local mine grid. These map sheets only showed rock type, not stratigraphy, and so were of limited application in a structural or mineralization sense.
In addition to the district scale exploration mapping, UKHM completed wide ranging drill programs. The results of a significant part of this drilling is incorporated into the current new map.
UKHM also completed extensive underground mine development and developed a number of open pits. Unfortunately, the exploration and mining geology were managed under separate departments and it is apparent that nomenclature and the recording of geological data was not consistent. The new surface geology map shows the location of open pits and underground portals or shafts but does not show the extent of the underground workings.
The map and accompanying presentation detail the history and methodology, stratigraphy and intrusions, structure (folding and faulting), and the creation of space for vein formation in the District. Alexco compiled historic data and conducted a field check to understand how UKHM geologists interpreted outcrops and open pits to observe mineralized structures.
The map is based on 1 : 5,000 scale mapping and derived from over 9,000 field observations collected over the period 2007 – 2019, with interpretation from 1 : 1000 scale maps covering over 9,000 historic overburden drill holes totalling about 250,000 m in areas of limited outcrop and 790 historic diamond holes totalling 46,700m.
This map also shows the distribution of all the approximately 16,000 historic overburden drill holes meticulously surveyed by UKHM. The work has been essentially designed for exploration purposes, with stratigraphic offset of mineralized vein fault systems permitting identification of new district scale exploration targets. Going forward, the geology in areas with little outcrop will be interpreted from new geophysical surveys and exploration drilling.
Printed copies of the map can be requested from the Yukon Geological Service by contacting their office.
EXPLORATION SUCCESS TIMELINE
2022
Alexco Reports 43% Expansion of Bermingham Indicated Resource to 47 Million Ounces of Silver at 939 Grams per Tonne; Remains Open
| Mineral Reserves & Resources | |
|---|---|
| Probable Mineral Reserve | 37.2 Moz Ag |
| Indicated Mineral Resource | 87.6 Moz Ag |
| Inferred Mineral Resource | 32.6 Moz Ag |
2021
| Mineral Reserves & Resources |
|---|
| Updated Mineral Resource to be completed by end of YE 2021 |
2020
Alexco extends Bermingham High-grade mineralization at depth
2019
Alexco intercepts high-grade mineralization at Bermingham Deep and discovers the Inca
| Mineral Reserves & Resources | |
|---|---|
| Probable Mineral Reserve | 30.5 Moz Ag |
| Indicated Mineral Resource | 83.6 Moz Ag |
| Inferred Mineral Resource | 24.3 Moz Ag |
2017 - 2018
| Mineral Reserves & Resources | |
|---|---|
| Indicated Mineral Resource | 84 Moz Ag |
| Inferred Mineral Resource | 23 Moz Ag |
2015
Alexco increases Flame & Moth Mineral Resource by 17% and Bermingham’s Mineral Resource by 37%
| Mineral Reserves & Resources | |
|---|---|
| Indicated Mineral Resource | 55.4 Moz Ag |
| Inferred Mineral Resource | 12 Moz Ag |
2012
Alexco issues first Mineral Resource estimates for Flame & Moth and Bermingham
| Mineral Reserves & Resources | |
|---|---|
| Indicated Mineral Resource | 51.3 Moz Ag |
| Inferred Mineral Resource | 7.74 Moz Ag |
2010 - 2011
Alexco announced Elsa Tailings mineral resource and discovered Flame & Moth. Alexco announced Lucky Queen’s and Onek’s initial Mineral Resource estimates, significantly expanded mineralized zone at Flame & Moth and discovered Bermingham.
| Mineral Reserves & Resources | |
|---|---|
| Indicated Mineral Resource | 18.9 Moz Ag |
| Inferred Mineral Resource | 5.4 Moz Ag |
2008 - 2009
Alexco increased Bellekeno Mineral Resource estimate
| MINERAL RESERVES & RESOURCES | |
|---|---|
| Indicated Mineral Resource | 11.9 Moz Ag |
| Inferred Mineral Resource | 1.1 Moz Ag |
2007
Alexco released initial Mineral Resource estimate of Bellekeno
| MINERAL RESERVES & RESOURCES | |
|---|---|
| Inferred Mineral Resource | 0.5 Moz Ag |
2006
Alexco began systematic mineral exploration at Keno Hill Silver District
More recently, our team has explored the deeper portion below Bermingham’s current mineral resource and discovered the high-grade Bermingham Northeast Deep silver mineralized zone. The 2020 surface exploration program returned some of the best high-grade silver intercepts in Alexco’s history in the District.
In March of 2021, Alexco launched an extensive surface exploration program to complete approximately 20,000 m utilizing directional drill technology to infill and extend the Northeast Deep zone mineralization. The Company expects to include the results of this drilling in a new Mineral Resource estimate in Q4 2021.
Alexco has also identified other step-out drilling targets in the District from the interpretation of aerial geophysical surveys conducted in 2018 and 2020. The discovery of the Inca Vein in 2019 demonstrates the potential for further exploration success in the District and highlights our commitment to continue growing through exploration.
Alexco estimates that to date, it has explored less than 15% of the Company’s holdings in the Keno Hill Silver District.
©
2022 Alexco Resource Corp.
All rights reserved.
All rights reserved.