Wednesday, January 2, 2013

Crevicing Still Remains One of Your Best Gold Recovery Methods (Part 7)

(Past "pard" Kane Fisher doing a bit of dry placer crevicing.)

For you individual small-scale gold miners out there, bedrock crevicing (both surface and underwater) continues to present good opportunities for placer gold recovery. You may not strike it rich crevicing, but if you get good at it and are patient, the yellow metal will come your way.

7. The Boulder Factor

I know what you're thinking. "Huh?" Yes, you heard right. There is a boulder factor when it comes to crevicing and gold "sniping."

Gold Concentrators
Metal Detectors

No, I'm not talking about boulders in their role as stream obstructions (although that's always important) but as a source for potential gold-laden cracks and crannies. Aside from a couple of astute readers who've emailed me on this subject, I suspect most small-scale miners have never thought about this angle much, if at all.

Interestingly enough, the boulders I'm talking about don't have to be resting on bedrock or even near it as long as they're in line with decent gold deposition points or lines. They just have to be large enough, and fissured and cracked in strategic spots that provide good gold traps.

The Light Bulb Goes Off

I learned about boulder crevices on a N. California river back in the early 1980s when I scrambled atop a larger than VW Beetle-sized granite boulder to check out a series of cracks on top of it running perpendicular to the stream flow. From two of those cracks I pulled three small nuggets and nearly 4 grams total in smaller stuff.

Needless to say, the light bulb went off in my head. After that I made it a point to check out cracks and crevices on larger boulders like these. So should you.

 (Good cracks and crevices can be found even with water-worn granite.)

Here are a few salient characteristics of these "creviceable" boulders that I've observed over the years to be salient:
  • They should be large enough to act as good obstructions and deposition points. I'm reluctant to suggest that "the bigger they are the better" but in my own experience that's been true. These larger boulders should be in good deposition locations relative to stream flow and completely covered by water during flood or high water events.
  •  They should have cracks or crevices in the upper portions or on top of the boulder itself. I've creviced more gold from cracks or crannies on or near the top of these things than I have anywhere else. Sometimes strategically located cracks on the downstream sides of large boulders can contain gold but don't count on that.
  • Their best gold-catching cracks and crevices run nearly perpendicular to the stream flow. Just common sense...perpendicular cracks act like riffles in a sluice box (to some degree, anyway) while parallel cracks are water chutes.
  • It doesn't matter if they're smooth and waterworn, composed of granite, or anything else. If they fulfill the conditions above then they're worth checking out. 
In crevicing, like all things mining, whatever works...works! Keep an open mind and a keen eye out, and who knows? You may be pulling boo-coo gold from a boulder crevice too.

If you liked this post, you may want to read: "Theories on Gold Nugget Formation (Part 4)"

(c)  Jim Rocha (J. R.)  2013

Questions? E-mail me at jr872vt90@yahoo.com

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