• COLORADO RIVER POTHOLES

At the eastern end of Laguna Dam, about ten miles northeast of Yuma, are the Arizona Potholes, where masses of black schist and coarse, granitic gneiss rise steeply for 250 feet above the Colorado River. An island dike of volcanic rhyolite rests inside the waters of Mittry Lake. This pink-hued rock contacts the other aforementioned intrusive and metamorphic formations. I scrambled all over this terrain and found small amounts of placer on both sides of the rhyolite. That might tell us a little something about the gold's source, eh? These placers extended even out onto the island. Erosion of veins and alteration zones along these volcanic/intrusive/metamorphic contacts produced coarse gold which, in all likelihood, was mined since early times. It's possible indigenous Colorado River people figured out that gold held some intrinsic worth. It's a cinch miners from south of the border knew, as did the gringos entering the country for the first time. Gold causes an infectious disease. As diverse cultures mingle, one group passes ‘the fever’ on to another. Eons before homo sapiens arrived, gold lodes had been eroding, forming placers. In places, some gold remains on pediments as well as in regional canyons, ravines, and smaller drywashes.  Extensions of other gold-bearing geological conditions had also been found in the granitic rocks of the California Potholes situated to the north of the Colorado River delta. These placers were also extensively-mined. Remnant channels, bits and pieces of older canyon systems and ravines became elevated over time. They now rest atop granite, rhyolite, gneiss, and schist bedrock in this geologically-mixed region. While I was never able to amass much gold from the Potholes, I did locate some luscious nuggets up to 12 pennyweight in size. Drywashing was my preferred method of extraction.

Still in Arizona, traveling to the far southernmost end of the Lagunas, you'll encounter the Gila River floodplain. These days, the area is dedicated almost entirely to agriculture. Crossing beyond this narrow strip of irrigated cropland, you'll encounter the northern tip of the Gila Mountains rising up from the desert floor. There are intermontaine ranges sprouting up everywhere across this region of California and Arizona. Turn off Rte 95 to the east and drive a few miles up a gravel road. You'll find yourself in the vicinity of the old ghost town of Gila City, an area which offers more recreational prospecting opportunities.

About twenty miles west of the Arizona and California pothole region are the Cargo Muchacho Mountains. Regional washes near the old ghost town of Tumco continue to producer some placer. About midway between these two east-to-west districts, but to the north of Yuma, lies Picacho Peak, another famous district where considerable mining occurred in recent years. Large-scale mining operations have pretty much obliterated any sign of the old placer diggings which, back in the early 1980s, were still prominent here.

 Local mining districts offer an interesting playground for snowbirds in the Yuma area. Researching a bit deeper discloses numerous other gold districts scattered throughout this portion of the Arizona desert. Unfortunately, many mineralized provinces lie on Military Proving Grounds, within Game Refuge boundaries, or on Colorado River Indian reservation lands. Although you're rarely, if ever, assured of finding gold, your chances are still pretty fair in the old wild west.

It's always advisable to check the claim status of public domain lands open to mineral entry. When you see old mine workings and such, there's a good chance they're either claimed or  inside land excluded from mineral entry. The Yuma county B.L.M. office is the place to find mining claim status as well as information on other lands residing in that part of Arizona. One possible shortcut which might help avoid some of the run around connected with finding a place to mine is to join a gold-mining club with valid claims. Fortunately, I had the run of the Laguna Mtns. which gave me ample room for prospecting to my heart’s content.