Dredging for gold is an old-fashioned mining method made new by modern technology. Since its resurgence, it’s become a popular way for small-scale miners to retrieve gold and other precious metals from public bodies of water. Dredging for gold using suction dredges can help the environment by removing excess sediment that can damage waterways. Sediment removal dredging focuses on removing built-up sediment and other obstacles from waterways to improve access.
Gold digging has an extensive history and is still practiced today. Sediment removal has become increasingly important as we rely on waterways for shipping goods. In this guide, we look at what gold dredging is and how it differs from sediment removal dredging.
What Is Gold Dredging?
Dredging uses equipment called a dredge to remove sediment from bodies of water such as lakes, rivers and streams.
Here’s a brief overview of how dredging for gold works:
- You lower a boom containing a suction or cutting attachment to the bottom of the water.
- The dredge’s rotating cutter uses its teeth to loosen the sediment.
- A submersible suction pump pulls the sediment up and into the dredge.
- You sort through the recovered material for gold.
Essentially, if you know how to dredge, you know how to dredge for gold. You’ll be able to keep your haul, though local regulations may limit how much you can take home with you.
Past and Present Gold Dredging
Gold dredging has changed dramatically over the past century. From enormous structures stationed on river banks to the portable machines of today, this mining method has a long history.
Early Gold Digging
The first gold dredges arose along rivers and streams. Standing multiple stories high, they contained complicated systems of heavy machinery that required a large team of operators to run. These dredges used a series of buckets attached to a moving line to scrape tons of sediment from the bottom of the water and carry it back to the building, where crew members sorted through it for gold.
The crew would then dispose of the waste material — known as tailings — by dumping it along river banks. These tailings piles would grow to ridiculous heights, sometimes even as tall as a multistory building. In fact, you can still see many of these waste piles today.
While these machines made sense at the time, they were ineffective by modern standards. For example, they could only mine in one place, so the amount of gold operators could recover was significantly limited.
The last giant gold dredge to close its doors was the Natomas Number 6 dredge in Folsom, California. It ceased operations in February of 1962 when operating costs grew to exceed the value of the gold recovered.
Gold Dredging Today
Since the 1960s, dredging has bounced back as a popular mining method. Modern dredges are far more compact than the original ones were, letting you mine in areas inaccessible to the giant stationary machines of old.
Many of today’s small-scale miners use amphibious suction dredges as their tool of choice, as they can drive them directly to the area they wish to mine. Hand dredges are another option, though they are significantly more limited in their reach.
Where to Dredge for Gold
You can go gold dredging anywhere it’s permissible under federal or local law. Regulations for recreational gold dredging differ from site to site. For example, you can freely pan for gold without a permit in some areas, but you may need a prospecting permit to use a dredge or sluice.
Additionally, some areas may be off-limits at certain times of the year to protect the fish population during their spawning season. Be sure to check all state and federal requirements and notices before setting out.
If you’re looking to make a profit, it might be worth visiting another area. The five states richest in gold, all located in the western part of the country, are:
While you’ll have the best chances of finding gold in these states, you can still dredge for gold in other regions. You’ll want to focus on the following areas, as gold-rich sediment usually gathers here:
- Banks of rivers and streams
- River mouths
- The base of waterfalls
In general, miners usually have luck in areas where water flows slowly. Sediment the water picks up in other areas will lose the speed to move through the water there, causing it to sink to the bottom and settle until someone removes it. It can also be helpful to look for debris like logs and large rocks, as these objects act as natural filters that separate gold from other materials.
What Is Sediment Removal Dredging?
Sedimentation is a natural process where sand, rock fragments, organic matter, silt and other debris are deposited at the bottom of waterways. Over time, this gradual accumulation of debris blocks waterways and can cause various problems, including blocking stormwater drains, restricting vessel access and exposing wildlife and people to pollutants. Sedimental removal dredging is a vital process that removes sediment from waterways like lakes, rivers, bays and harbors to improve access and water flow or protect the environment.
Sediment Removal Dredging Applications
Sediment removal dredging is used for various reasons in both industrial and environmental situations. Here are a few ways sediment removal is used:
- Maintaining waterways: Sediment removal is an essential part of waterway maintenance. It ensures bodies of water are free from dangerous debris that can damage ships and wildlife.
- Creating new waterways: Many goods are transported by ships. To help reach new destinations, sediment removal dredging can help create new channels that cargo ships of varying sizes can use to reach new markets.
- Increasing depth: Sedimentation can make waterways shallower. This can make vessels run aground or increase the chance of flooding during storms. Sediment removal dredging can increase the depth of waterways by stripping away accumulated debris.
- Cleaning bodies of water: Some bodies of water, like ponds and lagoons, may have stagnant water that causes them to smell. Sediment in canals can restrict access or make them dangerous to navigate. Trash can also accumulate in waterways, threatening wildlife and people. Dredging these bodies of water makes them cleaner and removes unpleasant smells. This makes waterways safer and better to use.
- Preserving water quality and ecosystems: Removing trash, pollutants, sludge, dead organic matter and other debris improves water quality. In addition, dredging can help prevent eutrophication, a process where excess nutrients in water cause a sudden spike in plant growth. Too many plants in a body of water reduce the oxygen available for other organisms, resulting in dead zones.
As you would expect, you’ll need a dredge for gold or sediment removal dredging. You can choose from four types of dredges:
- Plain-suction: As the most common type of dredge, plain-suction dredges use suction to remove loose debris from bodies of water. They cannot break down hard surfaces, so they are most useful for removing floating gold and debris.
- Cutter-suction: The cutting tool on these dredges cuts into the sediment, loosening the material and transporting it to the suction pump. They’re often necessary for breaking up especially compacted surfaces where plain-suction dredges lack the power for the job.
- Auger-suction: These heavy-duty dredges have a rotating auger that burrows into the water bed, loosening the sediment so that the pump can suck it up.
- Jet-lift: This high-tech dredge works by shooting a high-volume stream of water into the lake or stream, pushing nearby water and sediment into the delivery pipe and pulling the material into the dredge.
The type of dredge you’ll need will depend on the area you plan to dredge in. Research your intended site beforehand to learn what to expect.
How Is Gold Dredging Different From Sediment Dredging?
Gold and sediment dredging are pretty similar. In fact, most of the equipment used for gold dredging can be used for sediment removal. The main difference is the intention behind the action. Gold dredging is focused on removing gold and other precious materials from waterways. Sediment removal dredging is the intentional removal of accumulated sediment from bodies of water. Federal, local and state governments are responsible for disposing of dredged materials from sediment removal, while gold dredging teams are responsible for their waste.
Shop Dredges From GeoForm International
If you’re thinking of beginning a small-scale gold dredging operation, you can count on us at GeoForm International to provide the equipment you need for success. Our products can also be used for sediment removal dredging operations, large or small.
Our Dino 6 pontoon dredge is a uniquely portable system that we developed to perform where similar systems can’t. Its lightweight body is highly maneuverable, allowing you to work in lakes, narrow streams and many other areas that traditional excavators and hydraulic dredges are too large to access.
Need a little more power? We created the Dino 8 dredge system for mid-sized dredging jobs. Its 3,000 gallons per minute (gpm) pumping capability can pump further distances than other similar models. The Dino 8’s simple systems and components make it easy to operate, cutting your job time significantly and letting you get back to business.
We also offer top-of-the-line submersible pumps for hand dredging applications. These pumps range from 4 to 14 inches, enabling even more precise work.