i-80 Gold Corp‘s (TSX: IAU) (NYSE: IAUX) 2023 drilling program has successfully expanded mineralization in the Hilltop Zones and has made new discoveries in the East Hilltop area, along the western extension of the Hilltop fault structure.
On Tuesday, the company announced the discovery of new lenses of high-grade polymetallic carbonate replacement deposits (CRD) and skarn mineralization along the Hilltop fault structure at its Ruby Hill Property in Eureka County, Nevada.
Exploration drilling in 2022 had already discovered multiple zones of high-grade CRD and skarn mineralization along the newly identified Hilltop fault structure located on the south side of the Archimedes open pit.
The 2023 drill program is focused on delineating the known zones and testing for the potential of additional mineralization along the Hilltop fault. Early drilling has been successful in expanding mineralization in the Hilltop horizon over a strike length of 750 meters including the discovery of new lenses of high-grade mineralization in the East Hilltop area and also along strike to the west.
“Our 2023 drill program has picked up where we left off in 2022, expanding high-grade mineralization in several zones and resulting in multiple new discoveries,” said Tyler Hill, chief geologist of i-80 Gold.
These results confirm a substantial mineralized system that remains open for expansion making us optimistic of further discoveries as several of our priority targets remain to be tested.”
The East Hilltop target area has yielded the discovery of CRD massive and semi-massive sulphide mineralization located between the Upper Hilltop Zone and the East Hilltop Skarn Zone.
Read more: Calibre Mining’s execution has been very strong in Nicaragua: VIII Eight Capital
Read more: Calibre Mining well-positioned to continue organic growth through gold grade increases: Cormark Securities
Step-out drilling on Hilltop leads to high-grade CRD
The first hole to intersect this new zone of CRD mineralization was iRH23-10, which returned multiple high-grade intercepts, including 0.5 g/t Au, 226.1 g/t Ag, 9.7 per cent Zn, and 10.0 per cent Pb over 8.4 meters, as well as 3.2 g/t Au, 366.0 g/t Ag, 19.8 per cent Zn, and 10.2 per cent Pb over 0.9 meters. Definition and expansion drilling is currently underway, and the horizon remains open both along strike and at depth.
Step-out drilling along the western extension of the Hilltop fault structure has led to the discovery of high-grade CRD and carlin-type gold mineralization. Hole iRH22-09 intersected multiple zones, including 3.4 g/t Au, 11.0 g/t Ag, and 6.8 per cent Zn over 18.3 meters (Hilltop West), 9.9 g/t Au over 5.8 m (Ruby Deeps extension), and 9.2 per cent Zn over 3.0 m (Geddes CRD discovery). The Hilltop West intercept is a broad CRD breccia zone near the Holly fault, approximately 250 meters west of the Lower Hilltop Zone.
High-grade gold mineralization exists immediately below the breccia mineralization and is believed to be the southern extension of the Ruby Deeps gold deposit located around 200 metres to the north. Ongoing drilling now focuses on testing the area between these two zones.
Some highlight results from the initial 2023 drilling include:
- iRH23-09: 3.4 g/t Au, 11.1 g/t Ag, and 6.7 per cent Zn and over 18.3 meters (Lower Hilltop Zone), 9.9 g/t Au over 5.8 meters (Ruby Deeps Zone), 9.2 per cent Zn and 0.1 per cent Cu over 3.1 meters (Geddes Zone Discovery)
- iRH23-10: 0.6 g/t Au, 165.6 g/t Ag, 6.7 per cent Zn and 6.6 per cent Pb over 13.4 meters (East Hilltop CRD Discovery) including 0.5 g/t Au, 226.1 g/t Ag, 9.7 per cent Zn and 10.0 per cent Pb over 8.4 meters, 3.2 g/t Au, 366.0 g/t Ag, 19.8 per cent Zn and 10.2 per cent Pb over 0.9 meters, 0.3 g/t Au, 63.0 g/t Ag, 13.9 per cent Zn, and 1.6 per cent Pb over 2.3 meters.
- iRH22-69: 0.3 g/t Au, 25.3 g/t Ag, 5.8 per cent Zn and 0.3 per cent Pb over 10.7 meters (Blackjack Skarn Zone), 0.5 g/t Au, 13.5 g/t Ag, and 8.2 per cent Zn, over 5.0 meters, 11.6 g/t Au over 13.1 meters (Lowerjack Zone)
- iRH22-71: 3.7 g/t Au, 116.7 g/t Ag, 7.1 per cent Zn and 3.5 per cent Pb over 4.7 meters (Blackjack Skarn Zone), 449.0 g/t Ag, 7.0 per cent Zn and 16.4 per cent Pb over 1.4 m (Blackjack Skarn Zone)
The Geddes CRD discovery is a high-grade massive sulphide mineralization located in the footwall of the Holly fault structure in an area where there have been no previous drilling. The Geddes CRD zone is a new mineralized stratigraphic unit in the Geddes limestone that has only seen a few drillholes across the property.
Drilling efforts are also focused on defining and expanding mineralization in the Upper, Lower, and East Hilltop Zones. Since the initial discovery of the Hilltop Zone in mid-2022, the company has gained significant understanding of the controlling features of the CRD system, identifying the northwest trending Hilltop fault structure.
High-grade mineralization is present in both the hanging wall (north) and footwall (south) sides of the fault, and is thickest where subsidiary north-south and northeast-southwest structures intersect the Hilltop fault. Skarn mineralization develops along the Hilltop fault to the east towards the Graveyard Flats intrusive stock, with new results confirming the potential for significant expansion. Recent drilling has continued to intersect high grade mineralization, with assays still pending.
Read more: Calibre Mining reports record gold production in Q1 2023
Read more: Calibre Mining Nicaraguan operations thrive with hub-and-spoke model: Raymond James
i-80 Gold confirms mineralization in both horizons at Blackjack deposit
i-80 Gold is also conducting drilling in the Blackjack Deposit to better understand the mineralization for an initial resource estimate, which is expected to be released after the 2023 program.
The Blackjack deposit, which was discovered by Barrick Gold (TSX: ABX) (NYSE: Gold) prior to the acquisition of the property by i-80, is located directly beneath the Archimedes pit. High-grade skarn mineralization occurs near the Graveyard Flats intrusive stock and is underlain by high-grade Carlin-type gold mineralization in the Lowerjack Zone.
The ongoing initial drilling program is confirming mineralization in both horizons. The first two holes drilled to test this part of the property returned initial highlight results with assays up to 7.1 per cent Zn, 3.5 per cent Pb, 3.7 g/t Au, and 116.7 g/t Ag in the Blackjack Zone, and up to 11.6 g/t Au over 13.1 meters in the Lowerjack Zone. Neither of these zones are currently included in the mineral inventory at Ruby Hill.
Currently, the company is operating five drills at Ruby Hill to carry out a large-scale surface drill program for deposit delineation and exploration. Further definition of the Upper Hilltop Zone will be done once new drill pads are allowed and established. In the meantime, the East Hilltop target area, where significant mineralization is being discovered in a region with minimal previous drilling, is one of the primary focal areas.
As part of the 2023 program, the company will be testing several priority geophysical targets identified on the property. The ongoing infill and step-out drill program will help advance the company’s plan to develop an underground mine at Ruby Hill, accessed via a ramp from the Archimedes open pit. After completion of the 2023 program, the company plans to release an updated mineral resource estimate, which will include initial estimates for the polymetallic deposits, followed by economic studies.
The company plans to truck refractory gold mineralization from the underground operation at Ruby Hill to its Lone Tree facility once it becomes operational. Additionally, the company is exploring the possibility of processing polymetallic mineralization on-site at the existing Ruby Hill plant, and is currently working on a potential retrofit of the plant to a floatation plant that would recover both base and precious metals.
This would take advantage of the existing permitted infrastructure at Ruby Hill, which is expected to reduce both the permitting timeline and the expected capital cost of mine development. The Ruby Hill Property is one of the company’s primary assets and is home to core processing infrastructure within the Eureka District of the Battle Mountain-Eureka Trend, including an idle processing plant and an active heap leach facility.
The property contains multiple gold, gold-silver, and polymetallic deposits, making it one of the largest development-stage projects in Nevada.
Read more: Calibre Mining builds strong foundation for continued success in Nicaragua: Canaccord Genuity
Read more: Calibre Mining reports high-grade ore from Pavon central mine
Calibre Mining Corp (TSX: CXB) (OTCQX: CXBMF) is also operating in the Battle-Mountain Eureka trend in Nevada, where gold production in the state contributed 10,753 ounces to an overall quarterly gold production of 65,770 ounces. This was spread between its producing mines in Nicaragua and Nevada.
Shares of i-80 gold dipped 1.2 per cent on Tuesday to trade at $3.26 on the Toronto Stock Exchange.
Calibre Mining is a sponsor of Mugglehead news coverage
Follow Joseph Morton on Twitter