There is nothing quite so exciting as a natural gold nugget. As an experienced placer miner on an industrial scale, allow me to share some insights.
Nuggets can range from delicate thin leafs with beautiful patterns to great gobby hunks weighing several ounces or even several pounds, (though extremely rare), each with it's own personality and beauty. The most beautiful, IMHO, are crystalline gold nuggets that have experienced some rounding from tumbling and grinding in a stream over eons of time and nuggets with lots of quartz. The former look like sculptures of naked bodies all entangled with each other!
The old expression, "Gold is, where you find it." is not really true. Gold is where you find it now, but you can sure find it easier if you understand how it gets there. Gold being heavier than almost anything else, once liberated from it's host rock by erosion, will slowly move it's way down through the ground as it slowly moves with rain, flash floods, earthquakes, etc. until it works its way down to the immovable bedrock or a layer of clay. Once there, though it will seek cracks and crevices as it moves along the bedrock until it hits a reef or pinnacle of rock that blocks it from moving further downslope on the stream, or it lodges in a crack. It can also hang up on large boulders, which are excellent places to look under.
Your first priority is to find bedrock exposures in a likely environment. Shooting on gravel deposits in the bottom of a valley where you are more than the range of your detector above the bedrock is a waste of time, unless, you are looking for relics left by old timers, or you are shooting tailing piles. Tailings are very productive places to look. There, the gold missed by the old timers has been conveniently moved to the surface by a really strong, tough man or machine that processed it with really poor technology. They missed as much as they got in most cases! Especially nuggets have lots of quartz in them, making them lighter and more likely to make it through their sluicebox. I worked on a claim where we found a 2.5 ounce nugget in the LAST riffle of a very "efficient" modern sluice on a cut where we were reprocessing tailings using a better sluicebox design than the company used the first time. We got MORE gold on the second pass than on the first!
Gold is ALWAYS found in association with quartz and magnetite (magnetic black sand), so you want a detector that can discriminate and can punch through the magnetite (often cryptically called "mineralization" in detector marketing materials), which will generally be concentrated just above and among the gold. Find the higher concentrations of magnetite, and you will find the most likely places to find gold. If your detector can't deal with the magnetite that's in the way, you are going to miss lots of gold! If you find a chunk of metal, such as a bolt, or nail, or maybe a bullet, reshoot the same spot! Heavy stuff will settle to the same places!
Next, don't assume that rivers stay in the bottom of a valley! The big finds in the California gold rush and the Klondike were discovered to be ancient river channels that that been lifted up with the mountains and are high above the current valley bottoms. The ultra-rich creeks of legendary status, like Bonanza, Eureka and the Klondike River were where the modern streams cut through the old channels sluicing them and leaving the heavy gold behind in great concentrations. So if you are in a geologically likely area, look up! If you see large gravel benches, look for the bedrock interface at the base of the formation and that is where to start detecting!
In the case of the great California gold rush, much of the ancient river channel was overlain by lava flows, so they had gravel sandwiched between the lava and the bedrock and once discovered they went underground to get it.
So, gold is where you find it - usually at the very bottom of what is or was a river or stream. Look for geologic features like a serious narrowing of a valley by rock outcroppings pinching it from both sides. There is a place where the bedrock will be closer to the surface and there is likely to be concentrations of gold on both the upstream and downstream sides (upstream being the best, but you may have to work your way up from the bottom.) Bring along a big pry bar and a pick! When mining with big Cats, our best days were we had ripped our way 3 - 6 feet into the bedrock. That's when you get the nice big nuggets!
Happy hunting - I'd love to hear from anyone who finds success with these tips!
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« Last Edit: April 02, 2010, 02:09:23 am by NuggetHound »
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