Gunman Project, Nevada
The Gunman Project (Gunman) is centred on a high-grade zinc concentration near the Bald Mountain gold mine and about a 90 minute drive south of Elko in White Pine County of eastern Nevada. The mineralization on the eastern apron of the Diamond Range is deeply weathered to form high-grade zinc oxides. Drilling by Pasinex Resources Limited (“Pasinex”) in 2018 resulted in a significant new discovery of zinc sulphides beneath the zinc oxides. This provokes a radical rethink of Gunman’s exploration potential. The known mineralized occurrences run north-south and Pasinex has now staked ground extending five kilometres to the north and to the south of the initial ground holding to provide room for a major discovery.
The Company completed a helicopter magnetics survey of 218 line-kilometers, a mobile metal ion soil sampling program of 453 samples and a ground gravity program with 2,078 stations in the nine months ended September 30, 2022, at the Gunman Project in Nevada. A drill program commenced subsequent to the end of the quarter in November.
Exploration History – How We Got Here
In 1990, Western Mining (WMC) was exploring for gold guided by outcrops of Jasperoids in the basin west of Bald Mountain vectoring westward across a range front fault onto the eastern apron of the Diamond Range. WMC “stumbled” over what became the RH Main Zone high-grade zinc oxide discovery. Zinc was of little interest to a gold explorer. Cypress Development Corp. (“Cypress”) explored Gunman intermittently between 2000 and 2014. A total of 114 reverse circulation drill-holes and 17 diamond drill holes delineated a limited part of a trend including the RH Main, RH North and RH South prospects. Pasinex optioned this high-grade zinc-oxide property from Cypress in 2017 because of its similarities to its Pinargozu high-grade zinc carbonate replacement deposit (CRD) in Türkiye.
At Gunman and specifically in RH Main Zone reverse circulation drilling programs totalling 12,250 metres intersected zinc grades between 5% to 33% and also silver between 15g/t to 465g/t and some minor lead over substantial widths. The deposit has central zones of massive, strongly oxidized mineralization and halos of partial replacement and veining. The mineralization is within 125 metres of the surface.
Highlights of previous drilling by Cyprus prior to Pasinex involvement:
**Apart from BC-24, in the RH South zone, all intersections are from RH main zone.
Note: True widths of the drill hole intersections reported in the Figure 1 cannot be determined from the information available.
Pasinex Diamond Drilling
In 2018 Pasinex drilled four inclined and oriented diamond drill-holes to try and better understand the geology and the controls on the mineralization. During Pasinex’s limited surgical drilling campaign at RH Main, diamond drill hole SRDD-2018-001 cut 144 feet (43.9 metres) averaging 14.2% of oxide zinc from 142 feet (43.3 metres) – including 45 feet (13.7 metres) averaging 26.1% zinc and 242 g/t silver (5.6 ozs) from 160 feet (48.8 metres). Pasinex is now assessing potential similarities to the relatively nearby Eureka CRD District (2Mt of 1.65M oz Au, 39M oz Ag and 625M lbs Pb)1. Eureka ores were thoroughly oxidized so most of the zinc was flushed out.
Read the original press release here: Pasinex Resources Intersects Black-Shale Hosted Zinc Sulphides Beneath High-Grade Zinc Oxides at its High-Grade Zinc Project in Nevada
Black Shale DISCOVERY
The last drill hole in Pasinex’s drilling campaign, SRDD-2018-004 made a surprising discovery – the intersection of the black-shale-hosted zinc-sulphide 50 metres south and down-plunge of drill hole SRDD-2018-001. This is a highly unusual rock type to be mineralized in a CRD setting. The intersection was nine feet (2.74 metres) averaging 8.1% zinc from 289 feet (88.1 metres) and 11 feet (3.35 metres) averaging 5.7% zinc from 304 feet (92.6 metres).
TWO POSSIBLE EXPLORATION MODELS
This exploration project has now not one but two distinct and compelling exploration targets. The upper limestone-hosted high-grade zinc oxide mineralization may be the weathered top of a much deeper wall-rock Carbonate Replacement Deposit (CRD) while the shale-hosted zinc sulphide mineralization may represent the distal fringes of a very different deposit type – a shale-hosted massive sulphide deposit (SHMS). Alternatively these two deposit types may be related and not mutually exclusive.
On the eastern flank of the Diamond Range steeply dipping Ely Limestone of Pennsylvania age hosts the high grade zinc oxide mineralization. The Ely Limestone lies unconformably below the gently dipping Carbon Ridge Formation of Permian age. The Ely Limestone was folded during the Antler Orogeny prior to deposition of the overlying Carbon Ridge. The last hole in the recent drilling program intersected creamy low-iron sphalerite (zinc sulphide) at the base of the Ely Limestone. The black shale could be part of the Ely Formation. Another possibility is that it represents an attenuation of the Chainman Shale Formation of older Mississippian age. The contact between the Ely Limestone and the Chainman Shale Formation in this part of Nevada is conformable. The Chainman is extensively mineralized in Nevada and the main host to the Carlin Trend gold deposits. The late Professor Sam Carey, the renowned iconoclast and revolutionary geologist said “we must disbelieve if we can, challenge the model, never sit back and believe what you read or are told to believe and question everything rigorously and then if you do accept the model, you have verified it for yourself and you have made it your own”. That is how major discoveries are made.
The exploration potential for possibly two quite distinct deposit types has now emerged. On the other hand the oxide zinc mineralization in the limestones maybe be related to the deeper zinc sulphide mineralization in the black shales.
The CRD target: The Taylor Deposit sold (remaining 83%) by Arizona Mining to South32 for US$1.3 billion is an example of a major CRD deposit in neighbouring Arizona. Another good example of the potential prize is the historic Leadville Mine in Colorado which exploited a major CRD Deposit. Examples of major SHMS deposits further north in Canada would be Red Dog in Alaska and Sullivan in British Columbia and bringing us up to the present day would be Fireweed Zinc’s Macmillan Pass Project in the Yukon.
Pasinex asked world-renowned CRD exploration geologist Peter Megaw to visit Gunman and examine the drill-core. Peter commented: “I would note from the start that the evidence to date is that the CRD style mineralization present is clearly of economic size and interest and that chasing it is fairly straightforward. The purported SHMS mineralization known may be of significant volume, but some pretty strong evidence will need to be mustered that it is actually a different genesis from the fairly typical CRD mineralization. Gunman has the chemical earmarks of CRD mineralization: in fact it looks like it could be a series of stacked bedding replacements and oxide “smearing” between, similar to the relatively nearby Eureka District (2Mt of 1.65M oz Au, 39M oz Ag and 625M lbs Pb); Eureka ores were thoroughly oxidized so most of the zinc was flushed out”.
Bill Tafuri a highly experienced Nevada geologist, based in Park City, Utah, mapped the mineralized zones at Gunman in detail and commented: “the Gunman zinc-silver prospect represents a significant discovery and I expect could be expanded in size due to the extent of the presently known mineralization being open in several directions plus the excellent potential to make additional discoveries in the expanded claim-block”.
Dr Neal Reynolds of CSA Global is a recognized international expert on zinc mineral systems, including SHMS and lower temperature Irish-style and MVT deposits. Pasinex asked Dr Reynolds to consult on Gunman and he visited the site and logged the drill-core from the recent drilling program. Dr Reynolds commented: “the important point is that it is a significant system and that we can better use available historical data to understand it and design an effective test that is inclusive of both CRD and SHMS models”.
Pasinex has reached an agreement with Cypress Development Corp. (“Cypress”) and Caliber Minerals Inc. to change the terms relating to the earn-in option agreement on the Gunman (formally Spur) zinc exploration property in Nevada, USA.
The agreement extends the deadline to complete the minimum of US $200,000.00 of qualified exploration expenditures to on or before June 30, 2022.
For further clarification on the original deal, click here: Pasinex Announces Option to Acquire 80% of the Gunman High-Grade Zinc (Silver) Project in Nevada and Substantially Increases the Surrounding Ground Holding
1Graton Sales volume 1968 – historic production of oxides. A larger tonnage of sulfide ore remains unmined and there is a possible genetic link to surrounding multi million ounce gold deposits