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El Padre vein: bonanza-grade drilling, open in every direction

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Setting

Sierra Madre Occidental, at vein scale

Charay lies at the western margin of the Sierra Madre Occidental, one of the world’s great epithermal precious-metal provinces and host to the majority of Mexico’s gold and silver deposits. Locally, the property sits at the center of a postulated ~12-km caldera ring of andesite porphyry centers, on one of the NE-trending dilatant structures that control essentially every deposit in the district.

District geology in depth →

The structure

A textbook bonanza vein

The El Padre vein is a near-vertical (–83° NW), 243°-trending, low-sulphidation epithermal quartz vein hosted in andesite of the Lower Volcanic Series. Textures are textbook bonanza-style — banded grey-white quartz, refractured and annealed by colloform, ribbon-textured chalcedonic quartz, with hematite–limonite after specularite.

Three hydrothermal phases are recognized; visible native gold has been observed in core, and metallics assays show no nugget effect. Vein widths run 1.0–2.0 m over a mapped length exceeding 400 m; four historic shafts and numerous pits trace the system across at least 550 m.

The 2005 core program

Independently recompiled in 2010

Twenty-seven NQ core holes (1,576 m) were drilled in 2005 by UK-listed Vane Minerals Group: nineteen targeted and intersected the El Padre vein along 240 m of strike. An independent Qualified Person (P.Geol.) recompiled the database in 2010, culling parallel-structure intervals and applying the true –83° vein dip. The full operator history →

Fig. 1 · Drill plan2005 diamond drilling, plan view: 27 core holes, 19 vein intercepts over 240 m of strike, with the Charay Breccia to the northeast.
2005 diamond drilling · 2010 independent recompilation · true widths. Parallel-vein interval from a second structure cut in the same hole. Diluted to a 1.8 m minimum mining width, the same intercepts still average 14.5 g/t Au and 88.7 g/t Ag.
HoleTrue width (m)Au (g/t)Ag (g/t)Vertical depth (m)
MCDDH-010.45.6185.115
MCDDH-01A1.324.9290.124
MCDDH-020.910.130.921
MCDDH-031.02.635.243
MCDDH-042.26.664.425
MCDDH-06nilnil
MCDDH-073.06.999.322
MCDDH-082.420.470.439
MCDDH-140.211.924.018
MCDDH-151.619.5172.831
MCDDH-161.611.4232.933
MCDDH-170.915.2343.642
MCDDH-181.242.339.848
MCDDH-201.541.7274.350
MCDDH-20 (parallel vein)6.816.5131.7~50
MCDDH-210.935.489.035
MCDDH-221.045.354.826
MCDDH-231.516.790.810
MCDDH-240.95.151.418
MCDDH-250.843.077.546
Weighted average (19)1.2920.3123.7

Intercepts grading 20 g/t Au or better

QA/QC

Verification a technical committee can sign off on

In 2007–2008 a second operator quartered and re-logged the core, photographed it, and re-assayed 155 pulps plus 159 new core samples at ALS (ISO 17025 accredited) with duplicates, standards and blanks inserted — no discrepancies noted.

The check compilation returned 18.8 g/t Au and 96.5 g/t Ag over 1.34 m (gold reproducing at 91% of the original laboratory), an unusually clean historical verification. Both databases, original assay sheets and certificates are available to qualified parties under confidentiality agreement.

Fig. 2 · Longitudinal sectionEvery intercept sits above ~50 m; grades increase with depth and the vein is open along strike and down-dip.

Geometry

The geometry of the opportunity

  1. No hole below ~50 m; no workings below ~35 m. In a deposit class routinely mined for hundreds of metres of vertical extent, the tested window is the top slice.
  2. Grade increases downward. Near-surface oxidized material runs under 10 g/t Au; the deepest intercepts grade 25 g/t or better — MCDDH-20 and MCDDH-25 end the tested envelope at 41.7 and 43.0 g/t Au. Silver holds steady throughout. This is the signature of a bonanza horizon entered from above, not exited from below.
  3. Open both ways along strike. The westernmost and easternmost vein holes both ended in +40 g/t material.

Beyond the vein itself: the parallel structure (16.5 g/t Au over 6.8 m in its single intercept) has never been followed up, and the Charay Breccia — a 500 × 200 m silicified body with surface samples to 7.5 g/t Au — is an untested bulk-tonnage target of the kind that anchors the economics of several Sierra Madre camps.

How this translated into production.

15,430 tonnes milled, 3,668 oz of gold shipped — the 2015 record is available on request.

Production & metallurgy Request the drill database