Mr. J. Duane Poliquin reports
ALMADEX ANNOUNCES UPDATED RESOURCE ESTIMATE FOR THE LOGAN ZINC/SILVER PROJECT, YUKON TERRITORY, CANADA
Almadex Minerals Ltd. has completed its updated mineral resource estimate (MRE) with respect to the Logan zinc/silver project, located in Yukon, Canada.
Indicated mineral resource of 2.6 million tonnes grading 5.1 per cent zinc and 23.1 grams per tonne silver;
Inferred mineral resource of 16.9 million tonnes grading 4.3 per cent zinc and 18.2 grams per tonne silver;
At-surface high-grade zone; amenable to open-pit mining;
Potential for resource expansion at depth and along strike.
The Logan project is located 108 kilometres northwest of Watson Lake in south-central Yukon. The project consists of 156 contiguous quartz mining claims located in the Watson Lake mining district, covering over 3,200 hectares. The project is located on the traditional territory of the Ross River Dena Council and Liard First Nation, 38 kilometres north of the Alaska Highway.
J. Duane Poliquin, chairman of Almadex, commented: "We are pleased to provide this updated resource estimate for Logan, which is a significant mineral endowment of a critical mineral located near infrastructure. This resource provides an excellent basis for continued study of Logan as a potential new source of critical minerals to support a lower carbon future."
The Logan deposit consists of fracture-hosted and vein-hosted zinc-silver mineralization within a granitic intrusion. The Main zone occurs along an 8,000-metre-long northeast-trending fault-related structure. The Main zone is tabular, dips 70 degrees to the northwest, extends for 1,100 metres along strike, varies from 50 metres to 150 metres in width, and has been traced to depths of 275 metres and remains open. The mineralization is up to 90 metres thick in relatively gentle terrain and minimal overburden, making it potentially attractive for open-pit mining. Recent drill core reanalysis indicated potentially economically significant values of the critical metal indium, not historically assayed for, averaging 35 parts per million indium and up to 273 parts per million indium. Indium is integral to solar panel manufacturing and a key input in semiconductors and many materials needed for advanced vehicle manufacturing.
The mineral resource estimate (MRE) and net smelter return cut-off sensitivities are presented in the attached tables.
Mineral resource estimation methodology
Modelling was conducted in the Universal Transverse Mercator (UTM) co-ordinate space relative to the North American Datum (NAD) 1983 and UTM zone 9N. The mineral resource block model utilized a block size of six metres (x) by six metres (y) by six metres (z) to honour the mineralization wire frames. The percentage of the volume of each block below the bare earth surface, below the modelled waste overburden surface and within each mineralization domain was calculated using the 3-D geological models and a 3-D surface model. For the open-pit optimization, block values were diluted. The MRE is reported as undiluted with an effective date of Jan. 17, 2023.
The Logan property drill hole database consists of 58 drill holes that intersected the interpreted mineralization wire frames. The zinc and silver assays were composited to two-metre composites lengths and the estimation utilized 2,651 composited samples. A total of 1.2 per cent of the total drilled metres inside the interpreted mineralization wire frames were not sampled, assumed to be waste and assigned a nominal waste value of half the detection limit of modern assay methods (0.0005 per cent zinc and 0.3429 gram per tonne silver).
Zinc and silver estimation was completed using ordinary kriging. The search ellipsoid size used to estimate the zinc and silver grades was defined by the modelled variograms. Block grade estimation employed locally varying anisotropy, which uses different rotation angles to define the principal directions of the variogram model and search ellipsoid on a per-block basis. Blocks within estimation domains are assigned rotation angles using a modelled 3-D mineralization trend surface wire frame, which allows structural complexities to be reproduced in the estimated block model. The number of variogram structures, contributions of each structure and their ranges are set per estimation domain and do not vary within the estimation domain.
A total of 201 bulk density samples are available from the Logan property drill hole database. Apex personnel performed exploratory data analysis of the bulk density samples available and the density was assigned for each domain in the Logan property. The density of the deposits ranged from 2.63 grams per cubic centimetre to 2.66 grams per cubic centimetre. The non-mineralized zones were assigned density based on lithological unit. The modelled overburden was assigned a density of 1.8 grams per cubic centimetre and the remaining country rock was assigned a density of 2.57 grams per cubic centimetre.
The unconstrained resource block model was subjected to several open-pit optimization scenarios to establish that the Logan project has the potential for future economic extraction. Blocks partially outside the mineralized wire frames were diluted with a nominal waste value of 0.0005 per cent zinc and 0.3429 gram per tonne silver based on the volume of the block outside of the mineralized wire frames. The process plus G&A (general and administrative) cost of Canadian-dollar net smelter return cut-off of $35 per tonne is used to determine potential mill feed and is approximately equivalent to a cut-off grade of 1.6 per cent zinc. Michael Dufresne considers the parameters reasonable to constrain the mineral resource estimate and establish that the Logan project has the potential for future economic extraction. The overall strip ratio for the Logan property open pit is approximately 5.3:1.
There are no other known factors or issues known by the qualified person that materially affect the MRE other than normal risks faced by mining projects. The Logan project is subject to the same types of risks that large base metal projects experience at an early stage of development in Canada. The nature of the risks relating to the project will change as the project evolves and more information becomes available. The company has engaged experienced management and specialized consultants to identify, manage and mitigate those risks.
Comparison of current and historical Logan deposit MRE
The current and historical 2012 Logan deposit MRE use the same drill hole database (see Almadex's news release dated May 26, 2022). The current Logan deposit MRE differs from a previously disclosed 2012 historical mineral resource in that was based on additional specific gravity (SG) data collected by Apex Geoscience Ltd. personnel during 2022, which resulted in a change in the SG used in the MRE from 2.95 grams per cubic centimetre for mineralized material and 2.7 grams per cubic centimetre for waste (2012) to 2.66 grams per cubic centimetre for the high-grade domain, 2.63 grams per cubic centimetre for the main zone mineralization, 2.57 grams per cubic centimetre for waste and 1.8 grams per cubic centimetre for overburden (2023). The 2023 Logan mineral resource SG data are based on a total of 204 SG samples collected during 2022 (see Almadex's news release dated Sept. 13, 2022).
In addition, mineralization wire frames for the deposit were remodelled based on lithology, alteration and structural geology logging to include a central high-grade zinc estimation domain (based on drill composite grades greater than approximately 3.5 per cent zinc) and peripheral lower-grade zinc estimation domain (based on drill composite grades greater than approximately 0.5 per cent zinc). The 2012 historical Logan deposit mineral resource utilized a single estimation domain also constrained by lithology, alteration and structural geology logging of drill cores and drill composite grades greater than approximately 0.5 per cent zinc.
Both the current and historical MRE both utilized ordinary kriging (OK) to estimate zinc and silver into six metre-by-six-metre-by-six-metre blocks in comparison with 10-metre-by-10-metre-by-10-metre blocks employed during 2012.
The 2023 MRE incorporated an updated mineral resource cut-off of 1.6 per cent zinc in comparison with 1 per cent zinc utilized in 2012. Significantly, the 2012 historical mineral resource was not pit constrained. Open-pit optimization parameters used in the current MRE are outlined in the notes to an attached table.
The Logan zinc-silver deposit is considered to exhibit significant potential for mineral resource expansion with mineralization open at depth on multiple drill sections, in addition to exploration potential remaining along strike. Given that exploration and delineation drilling of the deposit occurred during the 1980s, Almadex is assessing advances in geophysical survey equipment and 3-D inversion methods; including, but not limited to, induced polarization/resistivity, gravity, magnetic and electromagnetic surveys that may assist in targeting the expansion of mineral resources and potential discovery of new exploration targets.
About the Logan project
The Logan project has been explored by means of sequential programs of mapping, soil sampling, geophysics and diamond drilling since the 1980s. Access for past major work programs was facilitated with a 52-kilometre-long winter road from the Alaska Highway. In 1987, a 700-metre-long-by-20-metre-wide gravel airstrip was established on the property, which would likely require surface relevelling in order to be used now, but small, short-runway aircraft may be able to land at this time. The winter road permit was not renewed past 2009 and reopening the road would require further permitting. Currently, the project can be accessed by helicopter.
Work on the project completed by previous operators is briefly summarized as follows:
- 1979: staking of Logan 1 to 36 quartz mining claims to cover new zinc-silver-tin-copper gossan; geological mapping, soil and stream sediment geochemistry, hand trenching, and test IP, EM and magnetometer geophysical surveys.
1980 to 1985: additional soil geochemistry, claim staking, hand trenching and geophysical surveys were completed;
1986 to 1989: exploration drilling of 103 holes totalling 16,438 metres; 15 trenches totalling 2,412 metres and continuing soil geochemistry and geophysical surveys; metallurgical test work at Lakefield Research Laboratories under supervision of Strathcona Mineral Services Ltd.; flotation of both high-grade and low-grade zinc samples indicated that recoveries of 93 per cent to 95 per cent zinc and 85 per cent to 90 per cent silver could be projected to a zinc concentrate;
2003: additional staking and completion of a baseline environmental survey conducted in and around the project;
2006: Bell Geospace conducted an air full tensor gravity (air-FTG) survey;
2012: Wardrop, a Tetra Tech company, was retained to prepare a technical report, including a historical mineral resource estimate, on the project: the 2012 Tetra Tech technical report is treated as a historical mineral resource as a qualified person has not done sufficient work to classify the historical estimate as a current mineral resource and Almadex is not treating this historical estimate as current mineral resources.
Quality assurance/quality control and reporting
Almadex is currently preparing the National Instrument 43-101 Logan project technical report, which will contain details of the MRE. This report is required to be announced and filed on SEDAR and the Almadex website within 45 days of this news release.
The historical zinc and lead analyses which underpin the MRE were carried out at Bondar Clegg and ALS Chemex laboratories at North Vancouver, B.C. Preparation of samples for assaying is assumed to have involved standard crushing, grinding and pulverization to produce pulps for assaying by hot aqua regia and analysis by atomic absorption.
The qualified person's conducted reassaying of select mineralized intervals (approximately 5 per cent of the drill database) and collected a suite of samples for specific gravity (density) determination to verify the historic drilling results. In total, 232 verification samples were collected from representative mineralized intercepts geographically separated across the deposit (including 15 per cent QA/QC duplicate, standard and blank samples) comprising 231 metres of half drill core from three separate holes from the 1986, 1987 and 1998 historical drill campaigns. Replicate samples were submitted for analysis to ALS Canada Ltd. at its Whitehorse, Yukon (sample preparation), and Vancouver, B.C. (ICP-MS), facilities. ALS is an ISO/IEC 17025:2017 and ISO 9001:2015 accredited geoanalytical laboratory and is independent of the Almadex and the qualified person. Drill core samples were subject to crushing at a minimum of 70 per cent passing two millimetres, followed by pulverizing of a 250-gram split to 85 per cent passing 75 microns. A 0.1-gram sample pulp was then subject to multielement ICP-MS analysis by four-acid digestion to determine individual metal content (ME-MS61). Zinc and silver values greater than 1 per cent and 100 parts per million, respectively, were subject to overlimit analysis by four-acid ICP-AES (ME-OG62). The qualified person followed industry-standard procedures for the work carried out on the Logan project, with a QA/QC program. Blank, duplicate and standard samples were inserted into the sample sequence sent to the laboratory for analysis. The qualified person detected no significant QA/QC issues during review of the data. Almadex and the qualified persons are not aware of any drilling, sampling, recovery or other factors that could materially affect the accuracy or reliability of the data referred to herein.
The scientific and technical information contained in this news release has been reviewed and approved by Michael Dufresne, MSc, PGeol, PGeo (Alberta and British Columbia); Kristopher J. Raffle, PGeo (British Columbia); and Alfonso Rodriquez, MSc, PGeo (British Columbia), president, principal and consultant and senior geologist of Apex Geoscience Ltd. of Edmonton, Alta., and they are independent qualified persons as defined in NI 43-101, Standards of Disclosure for Mineral Projects. Mr. Dufresne, Mr. Raffle and Mr. Rodriguez verified the data disclosed, including a review of the analytical and test data underlying the information and opinions contained therein.
Almadex is an exploration company that holds a large mineral portfolio consisting of projects and net smelter return royalties in Canada, the United States and Mexico. This portfolio is the direct result of many years of prospecting and deal making by Almadex's management team. The company owns a number of portable diamond drill rigs, enabling it to conduct cost-effective, first-pass exploration drilling in-house.
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