Nothing is as rewarding as panning or sluicing for gold. Usually I go out with the gold pan in one hand and a fishing rod in the other. I set the fishing rod up with a float in a calm pool then go dig in potential gold rich gravel under some willows.
The beauty of mining for gold in a river is that there is always gold. My favorite is the Fraser River in BC Canada, but, these techniques apply to any river. The key to river mining, especially big rivers, is to recognize it is one big natural sluice box. The course gold starts where the main discovery was made [for the Fraser River it would be Barkerville] and from there the gold washes downstream to finally be dumped into the ocean at Richmond BC. This gold approach applies to ALL rivers. The natural current flow will automatically sort out gold from the big heavy course stuff to the flake material and finally the fine flour gold in river deltas. I use this understanding to extract the size of material I want when I go gold mining. What I haven’t told you yet is that there are secrets and tricks you can use to make your job a lot easier to gather good quantities of gold in choice locations along the river.
So, if the river is a sluice box how do we use this information? First, we establish the” knowns” like:
- Does the river have a history of gold mining?
- Are there any gold reports indicating where miners have worked the bench gravel and the quantity of gold taken?
- Are there ghost towns along the river?
- Is there any old mining equipment, dredges, sluice boxes or old machinery in some of the locations?
- Where was the main discovery of gold along this river?
I will continue to use the Fraser River in BC Canada as an example to show you how a little knowledge can go a long way. First we discuss the easy obvious gold. Almost all rivers will have a stretch of gravel banks that are/were rich in gold. History will show that a stampede of prospectors mined this gold and that a small town probably sprung up to a mark its location. In the case of the Fraser River, that spot would be Boston Bar.
Great quantities of flake gold were extracted from gravel and sand bars in that section. These areas almost always exist on rivers so watch out for them. When you find easy flake gold, or read mining history reports about them, mark that location on a detailed map. The finer flour gold will be downstream from that area and the coarser heavier gold will be upstream from that spot. The only exception to that rule will be in the center of the river where the main current flow is; more about that later.
As you work your way upstream from this spot you will still find flake gold only it will be more "spotty". The surface gold will diminish except behind very large rocks and in accessible bedrock cracks. Since the rivers flow surges during rain storms or during the spring melt is a natural scouring action takes place throughout the rivers channel. The blast of seasonal water can move rocks as big as houses further downstream at peak flow. Any exposed gold particles are carried to wider river locations such as gravel and sand bars where a natural slow and steady accumulation takes place. However, back upstream, the larger, heavier gold pieces and nuggets work their way through various layers of rubble during these high water flow rate. As rocks weigh less underwater and are easier to move around the mixture of intense water movement and hydraulic hydration makes gravel "porous" which allows gold to pass through various layers on its way to bedrock, although some exceptions do occur. If the flow rate is high enough and the gold piece is the right weight and shape it can be carried on a more surface oriented journey. This is where you can find "clinkers" or small nuggets about the size of a piece of rice up in rock shelves. In addition, rivers change course many times during their life span and will erode away many sand and gravel banks. This material gets carried downstream to be re-deposited. Again, most of the time this will happen during high flow rates when the rivers flow peaks. The exception here is when trees are up rooted or large boulders are moved around blocking part of the rivers original flow. When this happens water is deflected off the restriction and will wear away surrounding gravel banks even during low flow conditions. Always watch for landslides
or temporary flow restrictions in the river. Quite often at low water levels the lower sections of exposed gravel banks will be open to gold mining as gold is usually the last thing to move away due to its weight. Now, one last thing about flow restrictions in rivers, I need to mention to search the trailing edge of the banks for natural concentrations of gold. Typically the current will wash away the surface gold as the river "eats away" at the dissolving bank. This heavier gold is only washed down to the end of the bank and will accumulate just over the end where the current slows slightly. It is like finding a glory hole when you hit these sections as they will have multiple layers of rice sized small nuggets in a tapered edge at the end of the bank.
OKAY BACK INTO THE RIVER
I mentioned how the heavier gold will penetrate down through the silt layers to ultimately stop on bedrock. I should also mention that where the river is forced to go around the bedrock outcropping
or solid restriction, the forward and top edge will have the largest, heaviest gold. What is happening here is that even though the gold is headed down, the rivers flow will "drive it up" onto these solid bedrock oriented shelves during high flow rates. Remember, this gold driven flow only works on bedrock areas that rise out of the river to form a restriction or bank on outside bends. If this same formation was a sand or gravel bar you would only find flake and fine gold in this location. The heavier gold will find a way to penetrate down through the silt layers until it stops on bedrock.
WORKING GRAVEL AND SAND BAR FOR GOLD
Gravel and sand banks are common on most rivers. Some even have trees growing on them, but there is a way to approach these potential wealth producers to maximize gold recovery. A lot depends on the type of gold that the river is carrying and by that I mean the size, flow rate and distance from the source the gold has traveled. Either way, the river will automatically carry and distribute flake material in greater densities on favorable riverbanks.
Most people think the closer to the source the more gold you will find, however it doesn't work the way. If you are close to the source of gold that is eroding into the river, due to its size and weight, it will be deep. Yup; that’s either on or getting close to bedrock. Flake gold happens when time and grinding rocks reduce nuggets to small flake size pieces. This process takes many thousands of years and every time the river changes course it washes away some gravel banks to make new ones. This course change is usually done during extremely high water flow rates, or at least start that way. Typically there will be an extra heavy winter of snow or it will rain straight for seven days plus. When the snow melts or the rain fills the river over its banks, massive boulders located in the bottom of the river will tumble around and block part of the main river channel. This forces the flow into different directions such as at a well-established bank.
Depending on the flow rate, the water will take 1 to 30 years to "eat away" the existing bank and create a new channel. Some rivers don't have especially large rocks in them and this is where large flash floods will overflow the river's banks and burst into a new channel. The water, through force, will "hydraulic" or blast a new channel through, simply based on the grounds weakness or ease of erosion.