Aztec holds a 75% interest in the Tombstone Property Joint Venture, which includes most of the original patented mining claims in the district as well as some recently acquired properties. The three drill holes are part of a recently completed 7-hole program that was drilled in a fan-grid pattern over the length of the Contention zone target. Multiple underground mine workings were intersected in all the drill holes.
High grade gold and silver was encountered in TC23-02 within a zone of oxidized, altered siltstones/hornfels, sandstones/quartzites, Qfp dikes and hydrothermal breccias at depths between 13.7 m and 135.0 m. Drill hole TC23-02 intersected, at 86.9 m to 132.1 m, a broad, oxidized zone of 45.3 m averaging 1.69 gpt Au and 29.07 gpt Ag (2.04 gpt AuEq), including 6.63 gpt Au & 72.81 gpt Ag (7.49 gpt AuEq) over a 10.1 m width. Gold equivalence (AuEq) for the drill hole intercepts were calculated using an 80:1 silver:gold ratio. Drill holeTC23-02 was collared 50 m west as a step to the 2021 drillholes on the 'M section line' on the western portion of the main Contention pit.
Drill Hole TC23-02 was initially drilled to a depth of 27 m, before difficult drilling conditions resulted in a temporary abandonment of the drill hole in mid-March. The drill hole was then re-entered in late April and was successfully extended to a total depth of 135 m. This hole crossed several workings related to the historic third and fourth mine levels, including backfilled stopes.
Hole TC23-06 was collared adjacent to the Grand Central shaft in the northern end of the Grand Central (South) pit. The vertical drill hole encountered from 29.6 m to 71.7 m an intersection of 42.1 m of 0.40 gpt Au and 30.79 gpt Ag (0.78 gpt AuEq) in an oxidized, high angle zone of altered siltstones/hornfels, sandstones/quartzites, mafic and Qfp dikes and hydrothermal breccias with multiple historic mine workings. It verifies the continuation and quality of the Contention zone mineralization between the Main (North) and Grand Central (South) pits.
Hole TC23-07 was collared in the northern portion of the Main pit adjacent to the east pit wall. The hole was drilled into the east pit wall and encountered from 6.1 m to 24.4 m an intersection of 18.3 m with 0.26 gpt Au and 7.43 gpt Ag (0.36 gpt AuEq) in oxidized, altered siltstones and sandstones and hydrothermal breccias with historic mine workings.
View drill sections here:
Link to section view hole TC23-02
Link to section view hole TC23-06
Link to section view hole TC23-07
Drill holes TC23-02 and TC23-07 were designed to expand the known mineralization in the central and northern portions of the main Contention pit to the west, east and to depth. TC23-06 verified the continuation and quality of the Contention mineralization between the Main and Grand Central (South) pits.
The core drilling program was planned to be able to pass through the intricate levels of old mine workings and multiple faults and to reach, at a minimum, the water table just below the sixth level and the principal district host limestones at depth. TC23-01, 05, 06 and 07 were able to reach their target depths. The drilling to date has expanded the extent of the entire Contention zone's mineralization to the west, east and to depth and demonstrates the potential for the volume of oxidized Au-Ag mineralization to grow as it remains open.
Aztec has now completed the seven hole core drilling program. Samples and their collection are controlled by an industry standard conforming QAQC program including insertions of certified standards, blanks and sample duplicates. The samples were regularly shipped to and received by the
Core samples are sawn and are continuously collected over 5 foot (1.52m) sample intervals from all drill holes. The samples were analyzed for gold with a 30-gram sample size using the fire assay method FA430 followed by multi-element MA300, including silver. Over limits, when present, are analyzed by MA370 or FA530. All holes contain certified blanks, standards, and duplicates as part of the quality control program.
The drilling program was designed with data obtained from surveys and modelling completed over 2022, following the conclusion of Aztec's previous RC drilling program in late 2021. Aztec has recently completed an ortho-topographic drone survey to construct detailed maps, surveyed all drill hole collars from 2020-21, sampled for Terraspec alteration analysis half of the North Contention pit, completed Terraspec analysis on all the 2020-21 RC chips, and advanced the construction of a wire-frame 3-D Leapfrog model of the historic, extensive, underground mine workings, with drilling, mineralization, geology, alteration, geophysics, and multi-element geochemistry.
To date the review of exploration data has defined the following target types for exploration at
Shallow, bulk tonnage, 'heap leachable'-type mineralization typical of
Sub-water table (below 200m depth) extensions of the typical Tombstone Au-Ag mineralization, composed mostly of secondary enrichment minerals and focused by the same horizon and structure types as the extensively mined shallow deposits above.
Deeper, high grade, '
The potential for a mineralized porphyry-type deposit as a source of the
Data obtained from the core drill holes is expected to supplement the previous, shallow RC drilling by providing extensive knowledge of geological relationships and testing at the depth of the water table and below the Contention system across its width and along its length. Notably, Aztec's previous drilling terminated above the water table where typically the enrichment of Ag occurs, and that the main host horizons of the
Upon the completion of diamond drilling, Aztec plans additional work including: Examining multi-element results for correlative, spatial, and geologic relationships.
Terraspec analysis of the drill core.
Detailed mapping of the
Update the drilling data into the Leapfrog model, and update known district drilling, geology (lithology, structural, alteration, mineralogy, mineralization age-dating), geophysics, geochemistry, and UG workings to identify mineralization trends to help target the shallow and deep-CRD drilling.
Examine the possibility of using seismic geophysics for identifying the overthrusts, faults and folding in the carbonates at depth.
A potential 43-101 compliant resource estimation
Tombstone Project Overview
The main target of the 2023 core drill program is to continue testing the shallow, bulk tonnage, heap leachable, mesothermal gold-silver oxide mineralization adjacent and below the previously mined Contention pit by infill and step-out drilling. Future drilling is expected to focus on strike and dip extensions of the shallow oxide mineralization, and move deeper to test for larger, deeper '
The
Host rocks to the mineralization were primarily the clastic sediments of the Cretaceous Bisbee Formation. Below 200 meters (m) in depth, the
Although the historic silver mines at
The 2021 drill holes were collared along the western rim and inside of the north and central parts of the
The low sulfidation epithermal gold-silver mineralization observed to date is impressive, marked by hydrothermal breccias, quartz veining and silicification associated with quartz-feldspar porphyry dikes and moderate to strong potassic, argillic and advanced argillic alteration and hornfels within the host
TR21-10: 1.39 gpt Au and 56.40 gpt Ag (2.20 gpt AuEq) over 96.0m
TR21-03: 5.71 gpt Au and 40.54 gpt Ag (6.28 gpt AuEq) over 32.0m
TR21-13: 1.80 gpt Au and 36.90 gpt Ag (2.33 gpt AuEq) over 70.1m
TR21-17: 1.73 gpt Au and 56.20 gpt Ag (2.53 gpt AuEq) over 64.0m
TR21-08: 2.09 gpt Au and 47.1 gpt Ag (2.76 gpt AuEq) over 39.6m
TR21-18: 0.76 gpt Au and 20.61 gpt Ag (1.05 gpt AuEq) over 64.0m
TR20-02: 0.94 gpt Au and 42.1 gpt Ag (1.60 gpt AuEq) over 77.7m
TR20-03: 0.77 gpt Au and 25.2 gpt Ag (1.07 gpt AuEq) over 97.5m
Gold equivalents are calculated using a 80:1 silver:gold ratio in 2020 and 2023 and a 70:1 silver:gold ratio in 2021. Reported lengths are apparent widths, not true widths. The Contention Au-Ag mineralization zones are generally west dipping at around 60-80 degrees, associated with the quartz-feldspar porphyry dikes. However, these dikes also extend as sills in shallow angles out from the Contention fault along fold noses in the
Tombstone Project Highlights
Well located property on patented (33) and unpatented (42) claims (452.02 hectares/1,116.94 acres), covers much of the historic
Historic silver district produced 32 million oz silver from 1878-1939, in high grade, oxidized, silver-gold-lead-zinc-copper vein and CRD deposits, and small open pit heap leach production in late 1980's
Drilling by Aztec in 2020-21 has demonstrated that the
Multiple other prospective targets in Cretaceous and Paleozoic rocks related to major NW and NNE trending structures hosting porphyritic intrusions crosscutting a possible caldera ring structure
A very important target is a potential bulk-tonnage carbonate replacement deposit in Paleozoic limestones similar to the
Distinct magnetic and AMT anomalies confirm multiple target areas, Contention pit hosts dikes along strongest district structure, excellent potential for CRD deposits with similar geology to the '
Aztec high-grade surface rock samples from the
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