As we continue to dig deeper (no pun intended!) into gold mining techniques, we will look another method which is calledgold dredging. This is another type of placer mining, which is extracting gold from the black sand that collects in placer deposits. The previous method of placer mining we discussed was gold panning, however gold dredging is more advanced and more efficient. So what the heck is this thing? Is it big or small? Does it require engines and laborers or is it automated? Let’s figure this thing out!
Gold Dredging Basics
The oldest gold dredging machines were huge! These suckers were several stories high when they were originally constructed in the early 1900′s. The way it works is this: The ones that work like boats go through the river and have a giant conveyor belt with buckets on it. They dig into the riverbed and pick up soil and lift it up to the top of the boat where the material is dumped off of this bucketline a larger sluice.
The biggest most clunky rocks are removed and then the leftover material at this point is moved into a trommel. A trommel is a rotating cylindrical screen that again only lets through smaller rocks. At this point the rocks are pushed into another sluice which keeps only the most fine materials. The big rocks that are tossed away are done so through a mechanism called tailing pipes. Other wise the leftover fine materials can be placed on a water table cradle and the gold can be extracted.
The Gold Dredging Concept
The fundamental idea behind collecting gold using a gold dredge has not really changed since the gold rush started. The basic concept is to filter away big rocks and then allow the gold to settle out of the fine black sand and then retrieve it there. Sluicing, rocking, dredging, panning, shaking, these are all methods of filtering the earth in different ways on different scales. The game is the same for each type though, and gold dredging is how the big boys do it on a very large scale. It’s always wash away the sand and gravel to reveal the gold, everytime.
This method had to be invented because all of the easily obtainable gold had already been recovered by gold panning and easier mining. But to get to the good stuff that was still underground it took big budgets and big machines that only big companies could provide. Steam and electricity made it very easy for these large barge dredges to run the rivers and recover massive amounts of gold that individual panners would have never gotten ahold of.
One-Man Gold Dredging
Nowadays there actually smaller one-person dredges that allow a person to go into the smaller banks in streams that big dredges couldn’t get into. This becoming more popular as people realize that it’s actually profitable and efficient. It’s like a one-man vacuum to suck up the bottom of the streams. Gold dredging is very interesting and nowadays it is something that we as single people actually have access to. Consider it in your arsenal in your gold prospecting adventures!