Gold-Bearing Bench Gravels (Part 1)
(More than two troy ounces of California placer gold.)
I've talked about gold-bearing bench gravels peripherally in the past, but in this series of posts I'll be addressing benches directly. Want to learn more about bench gravels? Then read on, my friend.
"High and Dry"
I suspect there are very few of you out there who don't know what bench gravels are. Moreover, a great many of you have worked benches at some point or another in your small-scale mining careers with greater or lesser success (hopefully the former and not the latter).
For those gold prospecting and mining "newbies" or novices out there who may not know, bench gravels are gold-bearing gravels that are typically found along the sides or banks of existing stream beds or dry washes, or that have been left "high and dry" some distance away from current stream courses. Bench gravels typically become available (i.e., "workable") for any number of reasons, including:
- Large-scale geologic events such as earthquakes, vulcanism, uplifts, fractures, etc.
- Low water conditions, heavy water usage, or damming upstream.
- Mud and rock slides.
- Streams or washes changing direction, shape, configuration, size, or depth.
I've found gold-bearing bench gravels in both wet and dry placer areas and have worked them hard with mixed success. Some were excellent gold producers and some were not (and I'll theorize on this issue a bit later), but when benches are good they are damn good. I'm talking coarse gold, small nuggets, "chunkers," fine gold, and flakes...and lots of them. Right off the bat I can think of three different bench gravel locations (two in California and one here in New Mexico) that I'd be working like a maniac this very minute if I could easily or legally.
(Note the bench gravels to the left in this photo.)
What this means is that it pays (literally) to get your nose out of that wash or stream bottom at times and take a closer look at the gravel banks to your sides or above and beyond you. That stream or wash you're prospecting or mining currently wasn't always right where it is now. In fact, very few gold bearing streams, creeks, rivers, gullies, dry washes, or arroyos follow the same path they did 100, 1,000, 10,000, 100,000, or 1,000,000 years ago. You can take that tiny piece of mining knowledge to the bank brothers and sisters.
There's more to come on this topic, so stay tuned.
(c) Jim Rocha (J.R.) 2014
Questions? E-mail me at firstname.lastname@example.org