Placer gold deposits that have accumulated in the gravels of a riverbed are generally the richest areas to look for gold, particularly in gold-bearing areas that have seen limited mining activity. Even in places that have been mined for centuries, there can still be good concentrations of gold in river gravels which are often rejuvenated with new gold with the high water each spring.
Efficiently mining for placer gold can be challenging. One of the best ways to process large amounts of gold bearing material is by using a suction dredge. For the average miner who does not have the ability to use heavy equipment, the dredge can be the best way to find a lot of gold.
There is a learning curve to successful gold dredging, but once learned it can be a very successful method, perhaps one of the few methods that will actually produce a good living wage for a miner today.
How a Dredge Works
Dredges are like an underwater vacuum cleaner. They essentially suck up the material from the bottom of a river or stream, pulling it through a suction hose to the surface, where the sand and gravel is run through a floating sluice box. The sluice is mounted between two pontoons, so the dredge can essentially be used anywhere in the river.
Water flows through the sluice are regulated by the water that is pumped through the suction hose and into the box. When set up properly, a suction dredge will capture a good amount of the fine gold while still allowing for good amounts of material to be processed.
The benefit of a good dredging operation is that there is a continuous supply of gold-bearing material to being supplied to the sluice. Unlike a basic sluice box that you would feed with a shovel, when you are down on the river sucking up gravel, you are able to move considerably more material with less work.
Different Sized Dredges
Suction dredges are sized based on the diameter of their suction hose. They can be anywhere from 1.5” up to 10” or larger on custom commercial applications. Most popular dredges are around 4” to 6”, which are a good size for a 1 or 2 man dredging operation.
Although the larger dredges can recover considerably more gold, larger sizes get to be extremely difficult to manage while underwater. They are harder to move and can really wear a miner out after a long day. A more modest size dredge is usually preferred because it can be run more efficiently and the miner will have energy to dredge all day without wearing out.
Getting Your Operation Set Up
Of course, locating an area that has paying quantities of gold is always important. Dredges run using gasoline engines, so there are costs associated with running them. To make it worth your time and energy, make sure that you are searching in areas that have a high likelihood of having gold.
In addition, you always want to do test samples with your gold dredge to attempt to locate the paystreaks of gold that will give you the highest gold yields. It’s really no different than you would do if you were sampling using a basic gold pan, except it is on a larger scale. Don’t waste your time in unproductive areas. If you want to recover a lot of gold, then make sure you are dredging in areas where the gold is heavily concentrated.
More about Gold Dredging Techniques
Underwater Diving Equipment
In shallow water you may not need any specialized diving equipment to use a suction dredge. You may be able to reach underwater with the nozzle to work in water that is only a few feet deep. However most of the time you will want to be able to dive down underwater and stay underwater for a long time at depth. In this case, you will need some diving equipment.
Staying warm is important, so a wetsuit or dry suit needed in most situations. In some warm climates you might not need them, but most of the times you will need the extra layer to keep yourself warm when staying underwater for a sustained length of time.
A good mask is important so you can see what you are doing underwater. You need a mask that fits you properly, and one that doesn’t fog up. Sometimes it takes some trial and error before you can find a mask that you really like, but since you are wearing it for the entire day you will want to make sure you get one that you like.
Of course you need air when you are underwater, so there are two ways that you can get it. In relatively shallow waters, you can use a snorkel with a tube up to the surface to supply you with air. This will work fine up to several feet deep, and during summer months when water levels are low this is often all that is needed for air supply.
In deeper water, most dredgers use what is called a hookah air system. These use the power of the dredges engine to generate air for breathing, and can even be set up to pump warm air generated by the engine into your suit to help keep your body warm. This is especially important when dredging during cooler climates.
The Future of Suction Dredging in the US
Suction dredges are probably the best way for the average miner to potential find large, paying quantities of placer gold. Even in rivers and streams that have previously been mined, a skilled gold dredger can recover good amounts of gold.
Unfortunately, in many states throughout the country, regulations are making it harder and harder to dredge for gold. Although a variety of environmental excuses are made, the truth is that dredging during the proper times of the year has no effect on fish or other wildlife, and is often perceived by the public that dredgers are “destroying” the environment somehow. This is despite the fact that all the gravel that they pull off the bottom of the river is dropped right onto the river bottom after it goes through the sluice box.
Dredging Around the World
At the same time that dredging is on the decline in the United States, many countries are ramping up their gold mining efforts and it is being found that suction dredges are a critical tool for recovering gold from waterways.
A while back, I saw a man wearing a t-shirt of one of the larger mining equipment manufacturers. I started talking to him and found out that he had recently purchased 2 large suction dredges and was planning to travel to his home country of Mali, Africa to mine for gold. The river that he was going to dredge had been worked by artisanal miners for centuries, but the dredge was going to allow him to access parts of the river that have never been mined before. Specialized equipment like this is making it possible to find new, undiscovered gold deposits all around the world.