Erris Resources and GreenOre plc entered into an option agreement on the 10th December 2019 to explore for gold on the Loch Tay Licence in Perthshire, Central Scotland. The licence area comprises 237 square kilometres of highly prospective ground within the Grampian Gold Belt, a region of Dalradian rocks which host several significant mineral occurrences and deposits of high-grade gold, base metals and baryte across Northern Ireland and Scotland.
Grampian gold deposits include the Curraghinalt deposit in Northern Ireland (6.09 Moz at 13.6g/t Au) and the Cononish deposit in Scotland (266 KOz at 13.4 g/t Au). An initial due diligence review, which involved preliminary prospecting and mapping by Erris Resources, has identified two priority target areas, Lead Trial and Glen Almond, as having excellent gold potential based on the presence of historic workings, mineralised outcrops and alluvial gold occurrences. With further work in February and early March 2020, prior to the restrictions introduced by the UK government to combat the outbreak of Covid-19, the Lead Trial prospect was significantly expanded with several high-grade gold boulders sampled in the Lead Trial – Dunan valley between 1.4km and 3km southeast of the historic workings at the Lead Trial Prospect.
The terms of the Option Agreement with GreenOre are as follows:
- Resources will have the option to earn 80% of the Loch Tay Project consisting of the Loch Tay Mines Royal Option from GreenOre by defining a minimum inferred resource of 250,000 ounces gold within four years of the date of the Option Notice.
- Upon defining 250,000 ounces within the required time frame, the ownership of the licence shall be allocated as to 80% Erris Resources and 20% GreenOre and any subsequent funding shall be on a pro-rata basis.
- In the event of either party failing to fund their respective portion, they will be diluted according to a standard industry formula. If either party shall dilute to less than 10% then that party shall forfeit all ownership and be entitled to a 2% Net Smelter Return Royalty (“NSR”).
- Erris Resources shall have the option to purchase 50% of the NSR for US$1M at any time prior to a production decision on the project
Lead Trial Target
In the Lead Trial area, small-scale workings for lead, which are hosted in felsites, have been mapped and include several trenches and a possible adit with associated dumps. The felsites intruded the Dalradian schists following the main regional metamorphic events such that they are unaffected by deformation. The felsites are interpreted to be part of a sill complex and are essentially subvolcanic rhyolite intrusives; elsewhere in the licence area, outcropping flow banded rhyolite has been found which resembles the felsite. The felsites indicate the presence of late-orogenic magmatic activity which could have driven hydrothermal activity and mineralisation of gold and base metals. Recent sampling by GreenOre has yielded high-grade gold associated with quartz-stockwork breccias within these felsites. Quartz stockworks in felsite containing variable amounts of galena, sphalerite and baryte have been found within an area of intermittent outcrop measuring 1.7km x 1km while mineralised boulder trains increase the length of the zone to approximately 3.2km in a northwest-southeast trend. The stockwork zones are thought to range from 0.5m to several meters in width and there could be several parallel structural zones present based on the distribution of mineralised boulders. The trend of the mineralised zones is approximately 160 degrees and is consistent with other occurrences in the wider licence area.
Samples taken by GreenOre from the historic workings returned encouraging results for gold, silver, lead and zinc. Two samples from separate workings returned the following: sample K06789 - 5.97g/t Au, 8.9g/t Ag, 2.21% Pb and 4.2% Zn and sample K24526 – 7.58g/t Au, 16.9g/t Ag, 4.43% Pb and 3.99% Zn. A boulder sample taken uphill from the workings returned a result of 8.74g/t Ag, 11.85g/t Ag and 1.66% Pb. The sulphides occur in vuggy quartz veins and stockworks indicative of shallow epithermal-style mineralisation. The Lead Trial prospect has recently been significantly expanded to the east to what is now called the Lead Trial – Dunan valley, where a cluster of mineralised boulders has been identified between 1.4km and 3km southeast of the historic workings at Lead Trial. The total mineralised footprint of the prospect has been increased to 3.2km in a northwest-southeast trend along the lower slopes and floor of the glen. Initial sampling prior to the winter of 2019-2020 identified mineralised float in the southeast area with 4 samples returning between 1.64g/t Au and 4.67g/t Au. Of the new results reported in April 2020, all of the 9 samples that returned >5g/t Au were taken in the new eastern area along with ten other samples with between 0.1g/t Au and 5g/t Au. The two highest grade samples with 17.15g/t Au and 14.8g/t Au were taken 210m apart on the lower slopes of the hill and they are considered proximal to a bedrock source. The sample with 14.8g/t Au is from a cobble of milky white and saccharoidal quartz with minor barite, galena and sphalerite collected in a burn. In addition to high-grade gold, the sample also returned 1.16% Pb, 1.35% Zn, and 10.35g/t Ag.
The highest-grade sample with 17.15g/t Au was from chips across a 1m wide vuggy quartz vein hosted in a 1.5m x 1.2m partially buried boulder or possible subcrop of mica schist. The sample also returned 12.15g/t Ag, 0.98% Pb and 0.97% Zn. The size of this boulder along with the clustering of high-grade float suggests that there is a very local bedrock source for this gold mineralisation. The south-eastern limit of the mineralised boulder train has distinct geochemistry with two samples returning low-grade copper (0.15% and 0.21%) and a third sample yielding high-grade copper, lead and silver with 1.61% Cu, 12.7% Pb and 247g/t Ag. This high-grade sample was a brecciated quartz cobble measuring 10cm x 15cm.
These are highly encouraging results and reveal a large mineralized system in the Lead Trial and adjacent areas. Further mapping, rock sampling and soil surveys are planned. The association of mineralisation with felsites and major structures in the area is important and this will guide exploration going forward.
Glen Almond Target
Some vein outcrops and alteration zones consisting of silicification of pelites and psammites were discovered in the Glen Almond area which is located 6.6km south of Lead Trial. The prospect lies 2.5km east-southeast of the Coire Buidhe silver mine, one of the more significant historic mines in the region where up to 18 veins were worked for high-grade silver associated with lead in argentiferous galena. A selective first pass grab sample from a 5-10cm quartz vein within a 1m altered zone returned 10.25g/t Au by fire assay. The aqua regia digest with ICP-MS analysis gave a result of 15.1g/t Au suggesting the presence of coarse gold. A second sample from another 5-10cm extensional quartz vein returned an initial result of >10g/t Au, a fire assay result of 2.32g/t Au and a result of 19.4g/t from aqua regia digest with ICP-MS analysis. In addition, a team from the University of Leeds which is studying alluvial gold, discovered a 10 gram nugget in the Glen Almond river within the Glen Almond target area in July 2019. The nugget is thought to be proximal to source due to its shape and association with quartz crystals which were still attached. A total of 77 fine gold grains were panned at a downstream site in Glen Almond as part of the same regional alluvial gold study. Further prospecting and mapping is required to locate the source of alluvial gold and expand the potential of the prospect.
Other Exploration Targets
A review of the lithogeochemistry for all rock samples collected on the Project has allowed the Company to identify new areas that require more detailed prospecting such as at Invergeldie in the south of the licence where 4 out of 7 samples collected in 2018 contained low-grade gold and a fifth sample returned 8.86g/t Au with associated high tellurium. The samples have not yet been followed up with further work. Other gold exploration targets have been identified at the Calliachar-Urlar area in the north of the licence area where some historic work outlined auriferous polymetallic veins. A review of the BGS stream sediment data for the region has also highlighted a new target area within the licence that requires prospecting in the upcoming field season.
The licence area, including the two main prospects, has good access, nearby infrastructure and is located in a region which has seen acceptance for mining projects. Recently, operations at the Cononish deposit owned by Scotgold (43 km to the west) commenced and a planning application was approved by Perth and Kinross Council in September 2016 for the Duntanlich baryte mine 25km to the northeast which is owned by M-ISWACO, a Schlumberger company. The Foss baryte mine located 18km to the northeast will be winding down operations once Duntanlich is in production. Initial land access agreements have been signed by GreenOre with the two landowners for the Lead Trial and Glen Almond areas. The Company believes that the prospects in the Loch Tay area have the potential to host significant gold mineralization and it looks forward to developing these prospects further to drill stage.
Figure 1. Project Location Map
Figure 2. Map showing prospects and exploration target areas within the Loch Tay Licence.
Figure 3. Map of all Lead Trial area samples showing gold results and recent highlights.
Figure 4. 10g nugget found in Glen Almond in 2019
Figure 5. Mineralised dump material taken adjacent to workings at the Lead Trial target.