Figure 1: Gravity data interpretation map showing the 3D gravity targets,
known copper sulfide deposits and major faults (overlaying topography).
Aston Bay Holdings Ltd. (TSXV: BAY) (OTCQB: ATBHF) ("Aston Bay" or the "Company”) reports on significant gravity anomalies in results from the high-resolution ground gravity geophysical program at the Storm Copper Project (“Storm” or the “Project”) on Somerset Island, Nunavut, Canada. The program was conducted this April and May by American West Metals Limited (“American West”), who are the project operator since entering an option agreement with Aston Bay in March 2021.
“These are spectacular results from the gravity survey conducted at Storm this spring by our partners American West,” stated Thomas Ullrich, CEO of Aston Bay. “The anomalies are large, with a strike length of several kilometres, and spatially coincident with the known shallow high-grade copper mineralization. Importantly, the anomalies are relatively shallow, with an upper boundary at about 200m depth, well within range of the diamond drill.
“The upper margin of one of the largest gravity anomalies was intersected by drill hole ST22-10 in the 2022 drill campaign. Targeting a conductivity anomaly, the hole ended in 68 metres of sulfide mineralization. Being both dense and electrically chargeable, the sulfide is a plausible cause for both the gravity and conductivity anomalies.
“Further, the dominantly pyrite-chalcopyrite sulfide mineralization in the intercept is the style of mineralization found on the periphery of the high-grade copper zones elsewhere at Storm. Here we have a drill hole intercepting peripheral-style sulfide mineralization on the margin of a very large gravity anomaly – this is an exciting target for the summer 2023 drill program.”
Figure 2: Chalcocite (with malachite alteration) is extensively exposed at surface at Storm
and suggests potential ‘leakage’ sourced from a large sediment-hosted copper system below.
LARGE AND DENSE BODIES DEFINED UNDER KNOWN COPPER MINERALIZATION
The gravity survey is interpreted to have effectively defined a series of dense features that are spatially associated with the interpreted graben fault architecture and known copper sulfide mineralization at Storm (Figures 3 & 4). These geological features closely adhere to the typical sediment-hosted copper model as seen in the large copper deposits of central and southern Africa and highlight the exceptional exploration potential of the area.
The interpretation has highlighted a series of NW-SE orientated gravity anomalies along the main Storm graben axis, which are discontinuous and/or are offset in places due to a series of N-S oriented faults. The anomalies appear to have higher densities where they intersect the main graben faults, and form a series of lobes with decreasing density away from the faults (Figures 1 & 4).
Figure 3: Total bouguer gravity anomaly image and graben fault architecture,overlaying topography.
Refer to Figure 4 for locations of known surface mineralization.
The ‘northern fault’ gravity anomaly extends over approximately 4.8km, is located to the north of the main fault, and is broken into two main zones. The easternmost zone is located directly below the 4100N Zone, where ongoing drilling has defined thick and continuous copper mineralization in the near-surface (<100m depth) over 1km of strike.
The ‘southern fault’ gravity anomaly is approximately 4km long, lies south of the graben fault, and is bounded by the 3500N, 2750N and 2200N high-grade copper zones.
Figure 4: Interpretation of the bouguer gravity data showing the anomalies spatial relationship
to the graben faults and known near-surface copper deposits (overlaying topography).
LARGE SIGNIFICANT TARGETS MODELED BY 3D INVERSION
A 3D inversion was completed on the gravity data to produce a series of gravity contrast iso-shells, which are designed to highlight the areas with the greatest density contrasts in 3D (Figures 5 & 6). These could represent potential areas of stronger copper mineralization and are high priority drill targets.
The largest of the 3D gravity targets is located along the northern fault and directly underneath the 4100N Zone (Figures 5 & 6). The feature commences at approximately 200m depth and is approximately 2.3km long. The gravity feature is coincident with a strong historical IP anomaly on its upper contact. This is a highly significant association and indicates a both dense and electrically chargeable body. The only known dense and chargeable geological feature at depth in the Storm area are sulfides.
Several other gravity targets are also defined by the 3D inversion along the southern fault. The data indicate that a strong gravity anomaly is located near the surface to the west of the high-grade 2750N Copper Zone. This location also features strong EM and IP anomalies associated with known copper mineralization in sparse, shallow historic drilling (5m @ 2% Cu and 0.8m @ 20% Cu in drill hole ST00-66).
Figure 5: Geophysical summary map showing the new gravity density contrast anomalies,deep EM conductors
and strong IP (>14Mv) anomalies (overlaying drill collar locations, graben faults and topography).
Figure 6: East-West long section showing the large density anomaly (red) underneath the 4100N Zone mineralization.
Note the strong IP anomaly (magenta) is spatially coincident with the top of the gravity anomaly.
DRILL HOLE ST22-10 –THE EDGE OF A MAJOR COPPER SYSTEM?
Exploration drill hole ST22-10 was completed in 2022 targeting a large EM anomaly to the west of, and at a deeper stratigraphic level than, the near-surface high-grade 4100N Zone. The EM anomaly is located on the southern edge of a strong airborne gravity anomaly associated with the northern graben fault.
The drill hole intersected a thick sequence of copper and zinc sulfide-bearing mineralization hosted within carbonate sediments before being abandoned due to technical drilling issues. Approximately 68.8m of chalcopyrite-bearing sulfide mineralization (Figure 7) was intersected from 277m downhole (approx. 230m vertical depth), remaining open at depth. The sulfide mineralization is interpreted to be stratabound and is hosted within a vuggy, bituminous and fossiliferous unit.
Figure 7: Chalcopyrite (copper sulfide), pyrite (iron sulfide), sphalerite (zinc sulfide) and galena (lead sulfide)
within vuggy bituminous dolostone in ST22-10 drill core from 313m downhole.
A distinct zonation of metal associations and mineralogy is noted at the 4100N, 2750N and 2200N Zones at Storm: a large copper-rich core (chalcocite, bornite and covellite) gives way laterally and vertically to thinner peripheral zones of copper-iron (chalcopyrite), iron (pyrite), zinc (sphalerite) and minor lead (galena). ST22-10 intersected the peripheral mineralogical assemblage (chalcopyrite, pyrite, sphalerite and galena) suggesting the potential for a nearby larger, more copper-rich core.
The metal associations and zonation of the mineralization suggest that drill hole ST22-10 potentially intersected the edge of a larger copper system.
Additionally, the geology displays all the elements required in the sediment-hosted mineralization forming process: permeable carbonate rocks to act as a fluid conduit and host mineralization, hydrocarbons to reduce metal-bearing fluids and force metal precipitation, sulfur source from bitumen and sour gas, proximity to faults known to be an effective source for plumbing, all within a favourable structural setting.
These key features are similar to many of the world’s major sediment-hosted copper systems, including the deposits of the Kalahari Copper Belt (Botswana) and Central African Copper Belt (DRC, Zambia).
The three-dimensional interpretation of the 2023 gravity data suggests that drill hole ST22-10 was drilled just to the south of, and likely intercepted the margin of, the large anomaly below and to the west of the 4100N Zone (Figures 5 & 6).
Both the metal zonation and geophysical modeling suggest the intersection of the periphery of a potentially larger mineralized zone. As such, the large gravity anomaly below the 4100N Zone and to the northwest of ST22-10 is a key target for the discovery of additional copper sulfides.
Diamond drilling will test this and other highly prospective exploration targets that sit at 200m to 500m below the surface.
Figure 8: Conceptual geological and exploration targeting model for the Storm Project,
showing depth of current drilling and conceptual location of discovery drill hole ST22-10.
GAME-CHANGING TARGETING TOOL
The 2023 high-resolution ground gravity survey was designed to follow up historical airborne and limited ground gravity surveys. The prior surveys had identified a series of broad density anomalies that lay adjacent to the large graben faults – interpreted to be conduits for copper-forming fluids - and below known near-surface copper sulfide mineralization.
Given the high contrast in density between copper sulfide mineralization and the mostly homogenous dolomite sedimentary host rocks at Storm, this geophysical technique was expected to be an effective targeting tool.
The new survey has provided high-quality data and a significant increase in the understanding of the Storm graben area. The survey included a total of 2,657 gravity stations (Figure 9), with an approximate station spacing of 150m x 50m (E-W and N-S respectively). Topographic surveying was performed simultaneously with gravity data acquisition, and terrain corrections were applied to the data.
Figure 9: Ground gravity station locations overlaying geology.
About the Storm Copper and Seal Zinc-Silver Projects, Nunavut
The Nunavut property consists of 173 contiguous mining claims covering an area of approximately 219,257 hectares on Somerset Island, Nunavut, Canada. The Storm Project comprises both the Storm Copper Project, a high-grade sediment-hosted copper discovery (intersections including 110m* @ 2.45% Cu from surface and 56.3m* @ 3.07% Cu from 12.2m) as well as the Seal Zinc Deposit (intersections including 14.4m* @ 10.58% Zn, 28.7g/t Ag from 51.8m and 22.3m* @ 23% Zn, 5.1g/t Ag from 101.5m). Additionally, there are numerous underexplored and undrilled targets within the 120-kilometre strike length of the mineralized trend, including the Tornado copper prospect where 10 grab samples yielded >1% Cu up to 32% Cu in gossans.
Storm Discovery and Historic Work
High-grade copper mineralization was discovered at Storm in the mid-1990s by Cominco geologists conducting regional zinc exploration around their then-producing Polaris lead-zinc mine. A massive chalcocite boulder found in a tributary of the Aston River in 1996 was traced to impressive surface exposures of broken chalcocite mineralization at the surface for hundreds of metres strike length at what became named the 2750N, 2200N, and 3500N Zones. Subsequent seasons of prospecting, geophysics, and over 9,000 m of drilling into the early 2000s confirmed a significant amount of copper mineralization below the surface exposures as well as making the blind discovery of the 4100N Zone, a large area of copper mineralization with no surface exposure.
Following the merger of Cominco with Teck in 2001 and the closure of the Polaris Mine, the Storm claims were allowed to lapse in 2007. Commander Resources re-staked the property in 2008 and flew a helicopter-borne VTEM survey in 2011 but conducted no additional drilling. Aston Bay subsequently entered into an earn-in agreement with Commander and consolidated 100% ownership in 2015. Commander retains a 0.875% Gross Overriding Royalty in the area of the original Storm claims.
In 2016 Aston Bay entered into an earn-in agreement with BHP, who conducted a 2,000-station soil sampling program and drilled 1,951m of core in 12 diamond drill holes, yielding up to 16m* @ 3.1% Cu. BHP exited the agreement in 2017. Aston Bay conducted a property-wide airborne gravity gradiometry survey in 2017 and drilled 2,913m in nine core holes in the Storm area in 2018 yielding a best intercept of 1.5m* @ 4.39% Cu and 20.5m* @ 0.56% Cu.
Agreement with American West Metals
An earn-in agreement for the Storm and Seal properties was signed with American West Metals in March 2021. Under the terms of the agreement, an expenditure of C$10m will earn 80% ownership of the property for American West. Aston Bay is carried for all expenditures to the completion of a feasibility study and production decision. If Aston Bay chooses not to participate and is diluted below 10% ownership, the ownership converts to a 2% Net Smelter Royalty, half of which is purchasable by American West for C$5m at first production. Aston Bay received a cash payment of C$500,000 on signing.
American West completed a fixed loop electromagnetic (FLEM) ground geophysical survey in 2021 that yielded several new subsurface conductive anomalies. A total of 1,534m were drilled in 10 diamond drill holes in the 2022 season, yielding several impressive near-surface intercepts including 41m* @ 4.1% Cu as well as 68m of sulfide mineralization associated with a deeper conductive anomaly.
In April 2022 results of beneficiation studies demonstrated that a mineralized intercept grading 4% Cu from the 4100N area could be upgraded to a 54% Cu direct ship product using standard sorting technology. Further beneficiation studies are ongoing.
In April 2023 American West embarked on a spring delineation drilling program using a helicopter-portable reverse circulation (RC) drill rig as well as gravity and moving loop electromagnetic (MLEM) ground geophysical programs. Results from the programs are in process and are released as they come available.
A summer 2023 program plans further delineation drilling of the near-surface high-grade copper zones to advance them toward maiden resource reports by late 2023. Diamond drilling is planned to test new high-priority gravity targets and environmental baseline studies will be initiated.
*Stated drill hole intersections are all core length, and true width is expected to be 60% to 95% of core length.
Figure 10: Storm Copper Project, Location Map.
Michael Dufresne, M.Sc., P.Geol., P.Geo., is a qualified person as defined by National Instrument 43-101 and has reviewed and approved the scientific and technical information in this press release.
About Aston Bay Holdings
Aston Bay is a publicly traded mineral exploration company exploring for high-grade copper and gold deposits in Virginia, USA, and Nunavut, Canada. The Company is led by CEO Thomas Ullrich with exploration in Virginia directed by the Company's advisor, Don Taylor, the 2018 Thayer Lindsley Award winner for his discovery of the Taylor Pb-Zn-Ag Deposit in Arizona. The Company is currently exploring the high-grade Buckingham Gold Vein in central Virginia and is in advanced stages of negotiation on other lands with high-grade copper potential in the area.
The Company is 100% owner of the Storm Project property, which hosts the Storm Copper Project and the Seal Zinc Deposit and has been optioned to American West Metals Limited.
About American West Metals Limited
AMERICAN WEST METALS LIMITED (ASX: AW1) is an Australian clean energy mining company focused on growth through the discovery and development of major base metal mineral deposits in Tier 1 jurisdictions of North America. Our strategy is focused on developing mines that have a low-footprint and support the global energy transformation. Our portfolio of copper and zinc projects in Utah and Canada include significant existing resource inventories and high-grade mineralization that can generate robust mining proposals. Core to our approach is our commitment to the ethical extraction and processing of minerals and making a meaningful contribution to the communities where our projects are located.
Led by a highly experienced leadership team, our strategic initiatives lay the foundation for a sustainable business which aims to deliver high-multiplier returns on shareholder investment and economic benefits to all stakeholders.
For further information on American West, visit: www.americanwestmetals.com.
Statements made in this news release, including those regarding the Option Agreement, grant of the Option and the expected closing date, American West’s interest in the Storm Project and its other acquisitions and plans, plans for the upcoming field season, management objectives, forecasts, estimates, expectations, or predictions of the future may constitute “forward-looking statement”, which can be identified by the use of conditional or future tenses or by the use of such verbs as “believe”, “expect”, “may”, “will”, “should”, “estimate”, “anticipate”, “project”, “plan”, and words of similar import, including variations thereof and negative forms. This press release contains forward-looking statements that reflect, as of the date of this press release, Aston Bay’s expectations, estimates and projections about its operations, the mining industry and the economic environment in which it operates. Statements in this press release that are not supported by historical fact are forward-looking statements, meaning they involve risk, uncertainty and other factors that could cause actual results to differ materially from those expressed or implied by such forward-looking statements. Although Aston Bay believes that the assumptions inherent in the forward-looking statements are reasonable, undue reliance should not be placed on these statements, which apply only at the time of writing of this press release. Aston Bay disclaims any intention or obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise, except to the extent required by securities legislation.
For more information contact:
Thomas Ullrich, Chief Executive Officer
Sofia Harquail, IR and Corporate Development