RE: Placing and war9 Sep 2025 20:39
Hey Mickey
I had to ask my AI friend and it said:
Short answer: yes—if GEO/Juno wants it, you can get solid “early signals” on site long before lab assays. You won’t get reportable gold grades, but you can quickly gauge if you’re in the right system and where to focus the next holes.
Here’s what works well after ~750 m of early drilling (RC or core):
Fast, on-site indicators (hours, not weeks)
Geology + logging
Quartz(-carbonate) veining, breccias, vein density changes.
Sulfides: arsenopyrite, pyrrhotite, pyrite; chalcopyrite if Cu is part of the system.
Alteration halos: sericite/biotite ± K-feldspar ± chlorite; magnetite destruction.
Magnetic susceptibility (handheld): drops often accompany sulfidation/alteration.
UV lamp: quick check for scheelite (W)—common in IRGS halos.
Visible gold (rare in IRGS, but note if seen).
pXRF (handheld XRF) on chips/core
Treat as qualitative/relative, not a gold assay.
Track pathfinders typical of IRGS: As, Bi, W (scheelite), Te, Sb, Mo, Cu.
Rising As–Bi–W trends across metres are a strong “vectoring” clue.
Build downhole plots (element vs depth) to spot halos and vectors immediately.
Portable hyperspectral (SWIR/NIR; e.g., TerraSpec/Corescan)
Maps white-mica chemistry (Al-IV), chlorite Fe-Mg, epidote—great for alteration zoning and vectors to hotter/more fertile fluid pathways.
Rapid scans of core faces or chip trays give a “heat map” of alteration intensity.
Downhole geophysics (if diamond or suitable RC)
Acoustic/optical televiewer for structures and vein orientations (refine targeting).
Spectral gamma to distinguish units; magnetic and sometimes EM tools to confirm conductors/sulfide zones.
Quick density/calliper logs to flag broken/altered intervals.
What “good early signs” look like in an IRGS context
Increasing arsenopyrite/pyrrhotite with strong sericitic–biotitic alteration.
As–Bi–W–Te rising into or flanking quartz-sulfide zones (pXRF).
Scheelite pops under UV near veins/breccias.
Hyperspectral shows tightening halos (e.g., higher-Al white mica) toward veining.
Mag sus locally depressed where sulfides/alteration overprint magnetite.
What won’t tell you the gold grade on site
pXRF for Au is unreliable (matrix effects, detection limits); use it for pathfinders, not Au itself.
Visible gold is rare/inconsistent in IRGS; absence ≠ low grade.
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