Lismore Project area is located in the southern sector of the world-class Irish Zn-Pb orefield. Adventus holds a 100% interest in six contiguous Irish prospecting licences (163 km2) covering the main extent of the Lismore Syncline. Diamond drilling by previous operators (1960’s to early 1990’s) such as RTZ (RioFinEx), Billiton, Central Mining & Finance and Navan Resources intersected significant zinc sulphide mineralization at a number of prospects in the west of the block in dolomitic rock matrix breccias.
Detailed stratigraphic-structural re-interpretation of the block and incorporation of published micro-palaeontological dating supports the presence of extensional faulting controlling sag facies development proximal to these areas of mineralization. The sag facies previously remained unknown and un-tested due to miss-identification of Viséan Limestone as Waulsortian Limestone and this observation is key in the identification of two drill-ready areas on the western zone of the Lismore block .
Work by Adventus Zinc has identified that untested potential remains proximal to these locations and is seeking to advance the properties to discovery, building on work conducted to date, via independent or co-operative investment.
The geometry of the licence block reflects the underlying east – west strike of the geology whereby the block is centrally dominated by Viséan Limestone and Waulsortian Limestone - host lithology to several Irish Type Zn-Pb ore deposits including Lisheen and Galmoy on the Rathdowney Trend. The style of alteration and mineralization encountered was reviewed by our technical team is considered analogous to that observed at economic deposits elsewhere within the Irish Orefield.
The Irish orefield has the greatest concentration of zinc per square kilometer on the planet and boasts the largest zinc mine in Europe - the Pale Beds hosted Navan deposit in County Meath. Other notable economic deposits within the orefield have included; Lisheen, Galmoy, Silvermines, and Tynagh which hosted mineralization within the Lower Carboniferous Waulsortian Mudbank (“Reef”) limestone. Situated on the southern margin of the Irish Zn-Pb orefield, the Lismore Block is now understood to have formed as a tectonic controlled asymmetric half graben developed as a result of initial regional extension throughout the late Devonian to early Carboniferous followed by later regional inversion during the Variscan orogeny. The Lismore Block was previously mapped as a syncline with fault preservation poorly understood to date.
The Lismore project area is open to year round exploration and is accessible via the national primary, secondary and local road networks. Mining and exploration activity benefits from Ireland’s stable fiscal and regulatory regime with excellent, and cost-effective exploration service infrastructure.
Historical shallow soil sampling programs delineated widespread moderate to strong geochemical anomalies including a 9km shallow soil anomaly (up to 7,000 ppm Zn). Historic diamond drilling programs on the Lismore (west) block encountered low grade zinc bearing breccias at shallow depths to the overlying geochemical soil anomalies.
With historic drilling primarily focused on the mineralized brecciated horizons at shallow depth encountering sub-economic occurrences, detailed structural-stratigraphic synthesis and geological reinterpretations undertaken by Adventus identified a series of potential targets proximal to these areas suggesting mineralizing systems with similarities to those which formed economic deposits in the Irish Midlands.
The Lismore block has good potential for the discovery of economic, Irish Type Zn-Pb mineralization and based on internal reviews of historic exploration a two-stage work programme is being pursued with phase one now complete.
Work included compilation, reprocessing and interpretation of all available historical geological, geophysical and geochemical data on the block. The fieldwork component for the block included;
1.Integrated rock and soil geochemical and mineral characterization studies of sulphide and oxide mineralization.
2.Remote sensing, re-processing of geophysical data and structural–stratigraphic synthesis study.
3.Detailed historical core logging/sampling and geological mapping-reinterpretation.
4.Lithogeochemical, shallow soil sampling and prospecting.
With phase one complete, the prospectivity of the Lismore (west) Block has been demonstrated through a detailed exploration program with semi-ready drill targets identified. Diamond drilling is warranted at Ballinanchor and Ballyduff as the next step forward to test for base of Waulsortian hosted mineralization at targets identified.
Prospectively of the Lismore Block
Encouragement of a potentially large mineralized system is suggestive with understanding the geological evolution of the block and basin tectonics preserving mineralization within at Lismore (West) Block; historic drilling intersecting significant alteration and mineralization at shallow depths including:
•1.3m @ 8.5% Zn from 165m (DDC3-4) Ballyduff
•2.9m @ 4.7% Zn from 33.3m (1556/5) Ballinanchor
•12.8m @ 3.0% Zn from 162m (DDC3-4) Ballyduff
•39.3m @ 1.76% Zn from 3.5m (1556/5) Ballinanchor
•0.15m @ 14.7%Zn from 165.9m (DDC3-4) Ballyduff
Some of the targets defined are based on detailed stratigraphic-structural interpretations with micro-palaeontological dating supporting the presence of extensional faulting controlling sag facies development proximal to the areas of mineralization. The sag facies previously remained unknown and un-tested due to miss-identification of Viséan Limestone as Waulsortian Limestone.
A series of untested geochemical anomalies hosted in Viséan & Waulsortian Limestone exist on the block including; Townspark, Ballinanchor West, Deerparkhill, Kilcloher & Lauragh.
The Lismore block has a series of features consistent with the development of large scale hydrothermal system(s) and is considered to be highly prospective for Irish Type Zn-Pb deposits;
- Widespread Zn anomalism in historical shallow soils, deep overburden, and stream sediment samples associated with dolomitized basal Waulsortian (drilling of a Zn soil anomaly was the primary exploration technique in the discovery of Lisheen).
- Structures overprinted by Variscan deformation with potential relay ramps .
- Host Waulsortian limestone with dolomitic breccias (similar to black matric breccias).
- Significant mineralization encountered – considered a distal expression of a larger system similar to distal deposits.