American West Metals Limited (ASX: AW1) has confirmed a significant discovery at the Storm Copper Project on Somerset Island, Nunavut, Canada with initial assay results from drill hole ST22-10.
“I am very pleased to be able to report that initial assays from drill hole ST22-10 confirm the presence of sediment hosted type copper and zinc sulphide mineralisation, with huge implications for the potential metal endowment of the project,” Managing Director, Dave O’Neill, said.
“These results demonstrate that – in addition to the near-surface high-grade copper deposits – we have a second type of copper deposit at Storm. This sedimentary copper mineralisation style is typically associated with very large deposits, such as the large-scale copper deposits in the Congo and the Kupferschiefer deposits in Central Europe.
“The discovery drill hole at Storm is associated with a series of large IP, EM and gravity anomalies that sit below or adjacent to the known high-grade copper prospects and major faults. These features occur across a zone more than 5,000m long, supporting the potential for a very large sedimentary copper system.
“This is a tremendous exploration opportunity and we are already planning follow-up exploration and drilling.”
New Style Of Copper and Zinc Sulphides Confirmed
Drill hole ST22-10 intersected a thick sequence of sulphide mineralisation hosted within carbonate sediments. The drill hole was targeting a large EM anomaly to the west, and deeper than the near surface high-grade 4100N Zone.
Approximately 68.8m of chalcopyrite, pyrite and sphalerite mineralisation was intersected from 277m downhole in drill hole ST22-10 (approx. 230m vertical depth). The mineralisation is interpreted to be stratabound and is hosted within a vuggy, bituminous and fossiliferous carbonate unit.
Visual observations of chalcopyrite and sphalerite in the drill core have now been confirmed by assays within the sampled intervals from ST22-10.
Of the sulphide mineralised zones, only portions containing clear and abundant chalcopyrite and sphalerite were sampled with the aim of confirming sediment hosted copper and zinc. Most of the pyrite-dominant zones were excluded from samples submitted for assay.
The results received confirm the presence of sediment hosted copper and zinc sulphide mineralisation and have verified the discovery of this new style of mineralisation at Storm.
Geophysical properties logging of sections of the core as well as further sampling will be conducted on ST22-10 to refine the targeting model for follow-up drilling.
ST22-10 is the deepest drill hole completed at the Storm Project this season and highlights the outstanding exploration potential of the project area.
Compilation of historical induced polarization (IP), gravity and electromagnetic (EM) data reveals a series of large anomalies that sit under, and adjacent to the known high- grade copper mineralisation and graben fault system.
The metal associations, zonation and geophysics suggest that the drill hole is potentially on the edge of a stronger mineral system.
Potential For Significant Sedimentary Copper System
Initial observations suggest that the style of mineralisation, host rocks and geological setting of the ST22-10 area are evidence of a reduced facies type of sediment hosted copper system. Global examples of these are the Kupferschiefer (Germany) and Central African copper deposits.
The geology intersected within ST22-10 has all the elements required for sediment hosted ore forming processes including permeable carbonate rocks, hydrocarbons for reducing fluids, sulphur source and a favourable structural setting. The central graben of the Storm area is an ideal trap for ore forming fluids and will be a key focus for further exploration.
The mineralisation encountered to date shows clear zonation which will be used to determine vectors to the stronger part of the mineral system.
The presence of zinc and lead within a number of stratigraphic horizons suggests that ST22-10 has intersected the distal parts of a copper dominant sedimentary ore system.
Forward Programme
Beneficiation test work is expected to commencement shortly with a focus on further optimisation of the process to produce a direct shipping ore (DSO) product. All of the remaining drill core (half core) from drill hole ST22-02 will be used in the test work.
Further diamond drilling and surface electromagnetics are planned to follow-up the new deeper discovery as well as the shallow mineralisation at the 2750N Zone.
The drilling will also aim to define initial resources at the 4100N and 2200N Zones, where thick zones of high-grade copper mineralisation have been intersected at shallow depths in historical drilling.
A detailed review of the existing induced polarisation (IP) and gravity anomalies is underway. The current datasets show a number of large anomalies that are focused around the central graben faults and sit beneath high-grade surface mineralisation, and therefore present as compelling targets for further exploration.
For further information please visit: https://www.americanwestmetals.com
