Steps to Success in Dredging

Tom Ashworth and Sons Clean Up
Tom Ashworth on his 8" Dredge
Tom Ashworth on his 8″ Dredge

I am sitting here at my home in Dayton, Oregon, at the end of January 1996.  I have a deep sensation of emptiness due to not being behind the nozzle of my suction dredge.  So I decided to write down the steps I use for success in dredging.

 It is not the cold weather that keeps me away from the Klamath River; it is the floods we had this year.  Some say it has been worse than the 1964 flood.  I don’t know, but I know it did a lot of damage this year.  The water in the Klamath River is very muddy, and I’m not particularly eager to dredge when I can’t see.  So instead, I decided to write an informative article on things that I have found to work well when I do get to go dredging.

Dredging for gold, for me, has been one of the most exciting and profitable recreations.  There has been much written about gold dredging.  Some of the stuff written works great, and other stuff didn’t work.  I will talk about some of the things I believe work and some that I think to sound good but don’t work.  Judge for yourself.


Some people think diving for gold is dangerous, but if you learn my steps to success in dredging, read books and watch videos, it is safe.  I have read some books where the author claims to be an expert on dredging and suggests using hip waders and never diving because of the dangers of diving.

Some say diving should only be done after hours of specialized training.  They are also told that diving is hard work and that you must be young to do it.  These people will buy a 2 or 3-inch dredge without hookah capabilities and work in shallow areas or where bedrock can be reached easily.  I have found that they have to work harder to find less gold than if they had bought a four or 5-inch dredge with hookah.

The main reason I believe this to be true is that the rocks in the river are larger than 2 or 3 inches, and it takes too long to throw the stones that would not fit in the suction hose.  Also, they usually have one plug-up after another in the suction hose or jet tube with this dredge.  Sure they can pack them into remote areas, but it has been my experience that a high banker would be a better choice.

When you wear waders and are not diving, you are bent over in an uncomfortable position, pulling rocks above the water’s surface to throw.  It is common sense that a stone is heavier out of the water than underwater.

Tom Ashworth Dredging for Gold
Tom Ashworth Dredging for Gold

I believe that diving for gold can be dangerous if you don’t use a little common sense.  However, I also think it is safe if you use common sense.  Most of my diving is done in chest-deep water.  I use protective gear, such as a wet suit, to keep me warm.

I suggest at least a 7mm thick Farmer John Style.  Then, you can remove the jacket when it gets warmer.  I use a tee shirt underneath the overall bib on the Farmer John Style.  Diving is also great because you can see the gold. So you know what layer or where on bedrock it is coming from.

You can’t see the gold if you don’t get your head underwater with a diving mask.  I also suggest you buy a diving mask with a purge on it.  It makes getting the water out of your mask easier if it fills up.  To get the water out of your mask, tilt your head forward and blow your nose until the water is out.

When diving, I am in a laying down position for dredging.  This is more comfortable than bending over with waders.  I believe it is easier to work a 5″ dredge than any other because they are not much heavier than the smaller dredges.  Still, they will move more gravel and have fewer plug-ups.  You can also use them to sample large rivers to determine if a super dredge is needed for a pay streak.


Tom Ashworth Gold Nugget
Tom Ashworth Gold Nugget

I believe that I have wasted more time dredging by not thoroughly sampling an area.  Most of the prospectors I see that are successful do sample an area to make sure it is worth bringing more equipment in.  I have some new rules for myself for sampling.

  1. Determine the minimum amount of gold I would be willing to work for daily.  For me, it is currently 1/2 ounce.
  2. Decide how deep you are willing to dredge to recover the minimum with your equipment.  I typically say that I will remove 1 foot of overburden for every 1-inch diameter of my suction hose.  Using my 5″ dredge, I can dredge up to 5 feet of overburden to recover 1/2 ounce of gold in an 8-hours.  If I use my 6″ dredge, then I can dredge 8 feet of overburden to recover 1/2 ounce of gold in an 8-hours.
  3. Decide where you would like to start.  I usually listen to people, read reports and look the area over to verify that its accessibility will be acceptable to me.  For example, if it takes you a week to pack a dredge in to sample, it may be fine if you dredge full time, but I only have 3 or 4 days off from my job per week, so this would not be acceptable for me.
  4. Draw out a sketch of the area.  Then, plan a sampling pattern that will allow you to discover any pay streaks on the claim.
  5. Dredge a sample hole of a fixed size and determine how much you dredged.  For example, if you dredge a hole 12′ long X 9′ Wide and 3′ Deep, you have just dredged 12 cubic yards.
  6. Measure the gold and determine if you can obtain your minimum amount with your equipment per day.  For example, I am using the above hole with 12 cubic yards.  If I use a 5″ dredge with a rated capacity of 12 cubic yards per hour, I multiply the rated power of the dredge by .667, which means the 5″ dredge will move eight cubic yards per hour.  Then I say I want a 1/2 ounce in 8 hours.  The formula works like this:


((True Dredge Capacity = (8 Cu. Yds.)) X (Number hours worked = (8 hours))) = (Total Cu. Yds. Per day = (64 Cu. Yds.))

Then you divide the Total Cu. Yds.  Per day by the sample size.

64 divided by 12 = 5.33 Sample factor

Then you take the amount of gold you want in 1 day and divide it by the sample factor.  In this case, we like 1/2 ounce or 10 Dwts. Per day.

10 Dwts. divided by 5.33 = 1.88 Dwts.

In the above illustration, we would have needed to find 1.88 Dwts.

If I find an acceptable sample, then I dredge several other sample holes.  That will help me determine the direction and length of the pay streak.  Also, it is a good idea to drop back to see determine the length of the pay streak extends.

The key to being successful at dredging is to sample.


These are just a few of the things I have found to work.  If you have any suggestions, please Email me, and I will try to add them so that we can help other miners.


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