(Most of Baja is arid and dry.)
In this, the third post of the series, I'll be passing along some specifics on gold in Baja California, Mexico as well as some general info. Again, if you're interested in doing a bit of prospecting or mining in Baja, make sure you get some detailed maps of the area(s) you're interested in and do your research up front on what's what down there these days.
Baja Placer Gold
Most of Baja's placer gold is derived from lode veins situated above low-lying areas. Geologists and historians state that no exceptionally rich lodes were discovered in either the northern or southern halves of the Baja Peninsula, but in certain locations ores ran as high as 2.75 troy ounces per ton. Now I know a bit about gold values per ton of ore material and I would beg to differ with the experts here. Even in the late 1800s and early 1900s a quarter to a half ounce per ton of material was considered "workable" (particularly the latter value) and today large-scale gold mining operations can make a profit in recovering mere grams per ton in open-pit type operations. I would say that nearly three troy ounces per ton is pretty damn good ground! However, other considerations such as difficulty in access or transport, water availability, processing issues, and veins being too shallow or pinching out early may be limiting factors in terms of the overall "richness" of certain lode locations.
Anyway, placer gold can be found in Baja as elluvial or alluvial gold that eroded out of veins or lode ore bodies. This is the typical scenario for most of the Peninsula's placer gold. However, there are a number of locations in Baja where the placer gold ground was NOT derived from lodes or veins and all I can surmise from this is that these placers were or are part of ancient, gold-bearing rivers or streams...perhaps even some Tertiary channels. In truth, I'm really not certain of the origin of those non-lode related placers so I'll defer to the experts in this regard.
Dry, Dry, Dry
As in most other gold-bearing areas, your best bet for finding placer gold in Baja is in auriferous gravels in gullies, washes, and alluvial fans. Some of these gravels are loosely consolidated and easy to get at and dig while others are cemented together very tightly or bound together with caliche ("desert cement"). Baja placer gold can also be found in benches, terraces, spread out along hillsides, and sometimes in capped pockets on the hilltops themselves. Your best bet is to prospect low-lying areas or drainages first (especially below old lode mines) and then try your hand in the benches, terraces, and higher up. Like always, the gold is there but it's up to you to find it.
Baja is, for the most part, dry, dry, dry. The Peninsula gets about 3-5 inches of rain a year overall so you'll be dealing with dry or desert-type placers for the most part. In the higher or mountainous elevations in the central part of Baja there is water in the form of a few running streams but expect intermittent water flow or no water at all in most instances. This means your mining plan of attack is strictly limited in Baja and it doesn't take a rocket scientist to figure out a dry washer is the optimum piece of mining equipment for small-scale miners in Baja.
That said, as dry as things can be in Baja, sometimes when you dig down a bit the material you want to run will be damp. You'll either need to dry the gravel out before running it or, as I once did, run it through your dry washer two or three times. If you do the latter, I estimate you'll be able to recover 75%-85% of the gold contained in those gravels. I know this isn't a pleasant idea for many of you, but let's get back to basics for a moment. What's my gold mining mantra? "Gold mining is very hard work for typically small returns." If you want Baja gold you'll have to work for it just like you do in any other location.
(Keene's Model DW212V battery powered dry washer.)
For prospecting in Baja, you may want to consider using a smaller, hand cranked or "slap handle" type dry washer of your own design and construction (you won't find these types of smaller "samplers" in the retail market). A nifty little sampler like this can be easily packed in or carried and can be used to test a number of spots or locations without all the fuss of setting up a larger, motorized or "main" unit. However, you can still sample by running test digs using your regular dry washer as long as you're willing to lug your gear, gas, etc. and break down and set up again and again. That's your call.
Honestly, one of those new-fangled battery powered dry washers (like the Model DW212V Keene Engineering manufactures) might be your best bet in Baja since it's a bit smaller and more portable (the unit...not the battery!). Yes, you have to recharge the battery (6-8 hours of use?), but they're quieter, don't require you to lug gas cans around, and are just as efficient. Just thought I'd throw that out there...
There's more to come, so stay tuned.
(c) Jim Rocha (J.R.) 2014
Questions? E-mail me at firstname.lastname@example.org