By Brad Jones
After years of drought, prospectors in the California Mother Lode and Desert Southwest are preparing their packs and checking over their mining equipment for the deluge of flood gold that is sure to await them when the winter rains subside and mountain snow melts.
In gold-bearing areas of California, heavy precipitation and high winds have already caused massive wind and water erosion through mudslides and flash floods with enough force to move sands, gravel, rocks and even large boulders. The heavier the rains, the more turbulent the water becomes and the more erosion it causes. For prospectors, it means gold that was previously lodged in hard-to-get places is now moving down the rivers and streams to replenish or create new placer and bench deposits. The more flooding, the higher up on the banks the bench deposits will be found once the river or stream returns to its normal level. By the same token, the alluvial placer deposits will be spread across a wider area on the lower, flatter ground below.
For most modern-day gold prospectors, it’s all about the alluvial deposits. Let’s face it, most of us are never going to stake a lode claim and invest in a hard rock mining operation for gold. Even if you’re optimistic enough to withstand the mental torment of the permitting process, which requires not only serious financial resources and skills but a virtuous degree of patience, one would have to be prepared to mine full time. And, for most of us, the prospect of giving up our day jobs or investing retirement funds into a gold mining operation is just too risky. Alluvial mining is easier, more enjoyable, and you can work a claim with basic skills, minimal equipment and gear. Still, one cannot rule out the possibility of striking a vein, and a rich enough find can make anyone a hard rock miner overnight.
If the storms are strong enough, erosion will break apart the host rock at or near the lode source and send large amounts gold from the source downstream to where the skilled prospector awaits with sluice in stream or pan in hand. The higher the volume and velocity of water flow, the more gold will be dredged up from the deepest pockets and densest clays — sometimes right down to the bedrock — from the bottoms of rivers and their tributaries where the biggest and heaviest nuggets are often lurking. Intermittent streams and desert dry washes that have not seen any activity or produced much gold in years, will come alive with water carrying fresh gold!
As the water velocity slows, the heaviest gold will drop out of suspension first, with smaller and smaller gold particles falling out where they may farther downstream as the wash slows to a trickle. This action will create a new layer of flood gold close to the surface. In a flash flood, these layers of gold may be even more pronounced if the water volume and velocity stop abruptly. As more rain occurs, the freshly deposited gold will begin to settle deeper into the wet ground but is usually found in the top six to 10 inches. If you find gold near the surface, keep digging. There might very well be an older layer or two of gold from previous storms underneath it.
Judging by news reports of flooding in the Mother Lode, the gold forecast looks incredibly auspicious. By all accounts, this winter has been the wettest in 20 years. But, it’s not solely the amount of precipitation that matters; it’s how often and how hard these heavy storms hit (and how fast snow in higher elevations melts) to create the strong bursts of erosion and turbulence needed to move more and bigger gold.
What happened to El Niño?
Despite last winter’s forecasts of the strongest El Niño in half a century, the rumors of its effect on the Desert Southwest were greatly exaggerated. In drought-stricken Southern California, El Niño just didn’t happen. But, it wasn’t only Gold Prospectors magazine that was led astray. We were in good company with the National Weather Service, the National Oceanic and Atmospheric Administration, the Weather Channel and a host of other scientific experts.
The ‘Blob’ and ‘atmospheric rivers’
With nobody to blame but themselves, scientists and weather experts are attributing this year’s rain to everything from climate change to “The Blob” and “atmospheric rivers.” Now, I’m no climatologist or weather geek, so I’m not going to wade into those murky depths — even if the water is warm. We can debate the notion of anthropogenic climate change by arguing with strangers on social media, or we can pack a Redneck Weather Rope in our gear and go for the gold. The choice is yours!
Common sense
Whatever the reason for the rain, it’s wet and there’s plenty of it. And, that means gold is moving. Turbulent water in gold-bearing streams and rivers will deposit new layers of flood gold and that means more color in our pans. Still, gold seems to have a mind of its own as to where it chooses to hide, so choose your prospects wisely.
How much water does it take to move gold?
Anyone who has ever prospected for gold, knows that gold is heavier than the water, gravel or blond and black sands in your pan. Gold, known as (Au) in the periodic table of elements, has an atomic number of 79, which means it’s much more dense than other earthly matter — platinum being the exception.
Gold has a specific gravity of 19.32, and while this term sounds delightfully scientific, it simply means that one cubic centimeter of pure gold weighs 19.32 grams. Even simpler, it means gold weighs about 19.3 times more than the same volume of water. In other words, a bucket of pure gold is 19.3 times as heavy as the same bucket
of pure water, minus the weight of the bucket itself.
So, if you’re planning on hauling a five-gallon bucket of pure gold out of the mountains, bring a sturdy bucket, a couple of mules and call an armored-car security service because your haul could weigh close to 900 troy pounds and be worth more than $12 million. Never say never, but that most likely just ain’t gonna happen. If you find one troy ounce a day, at $1,200 an ounce or even a fraction thereof, you’re doing better than your average gold prospector.
And, speaking of gravity ...
The steeper the hillside and gradient of the stream, the higher the speed water will flow downstream, so look for the areas where fast-flowing water suddenly slows because that’s where the heavier gold will drop out of suspension. One obvious place too look is at the bottom of waterfalls or where ancient waterfalls once flowed.
Of course, the downstream side of large boulders and the inside curves of a stream are hot spots for gold. It just makes sense. Meanders, or the S-shaped bends of a stream, erode more quickly on the outside curve and deposit more sediment on the inside curve because water flows faster on the outside of the bend. Also, look for large boulders, natural dams or logs and other debris that could slow the flow of water and trap gold.
Because gold is so dense, it hugs the bottom of rivers and streams, often the bare bedrock. This means it takes a tremendous amount of force to lift gold into the flow of water and carry it downstream. For example, if the force is strong enough to move baseball-sized rocks, it will move small particles of gold that we call gold dust, specks or “fly poop.” With gold this small, it would take several thousand pieces to make up one troy ounce. To move larger flakes or even pickers, the flow of water would have to be powerful enough to move larger rocks. And, to budge nuggets off the bedrock, the turbulence would be of such intensity that it could move boulders measuring several feet in diameter. This is why big nuggets don’t usually stray too far from their source.
Of course, all of this sounds good in theory, but can vary greatly depending on the shape, size and purity of the individual gold nugget. If the nugget is flat, for instance, turbulent water can produce a hydrodynamic “kiting”
effect, just as wind resistance does when you are flying a kite. However, a heavy, flat nugget may hug the bedrock, creating a streamlined effect, causing water to flow over and around it. It really all depends on the velocity of the water in the stream. On the other hand, if the nugget is worn and round from erosion, it will be more likely to roll than a nugget that has sharper edges or an irregular shape. And, if the nugget is less pure, or the gold is interwoven in quartz, it will weigh less, making it easier to move.
So really, to catch the nugget, you must be become the nugget (or at least be smarter than the nugget) and trace your most logical path of least resistance downstream from the elusive lode source. And remember, gold is where you find it, not always where the books say it should be, so learn to trust your instincts.
No matter how the color eventually ends up in your pan, whether you call it flood gold or just plain gold, at today’s prices it’s worth more than $1,200 a troy ounce. And, well, that’s something.