Parts List for 4" Subsurface Dredge

Hi,

You can no longer buy a subsurface dredge off the shelf. However, Keene still makes a 4", 5", 6", and 8" subsurface dredge riffle tube that you can use to make your own dredge out of off the shelf parts.

Here is the parts list for a 4" subsurface dredge I built:


4” SUBSURFACE DREDGE ( SUCTION NOZZLE )

PART # ITEM
KESS4 4” SUBSURFACE TUBE
KEPF25 2 – 2½” FLOATS
KESN42 4” X 2” SUCTION NOZZLE
KEP103BH 4HP HONDA PUMP W/BASE PLATE
OPTION - KEP103BCH 4HP PUMP W/T80 AIR COMPRESSOR
KESH4 15ft. 4” SUCTION HOSE
KEPH2 16ft. 2” PRESSURE HOSE
KESS72 4 – 4” HOSE CLAMPS
BJRB200125 2” X 1¼” REDUCER
KUPHC2F 2” PRESSURE HOSE COUPLER
KUSH15 4ft. 1½” SUCTION HOSE
KESS24 4 – 1½” HOSE CLAMPS
KESS32 4 – 2” HOSE CLAMPS
PANMM 6” MINERS MOSS
KEFV20 2” FOOTVALVE

NOTE: Frame is not included in this price because you will need to build your own. Tubing can be bought from Greer Tank. You will need 20ft. of 1” square aluminum tubing. See picture for simple frame assembly.

Two items of importance. First, I opted for a suction nozzle design as I wanted to allow the gold to settle before it gets to the box and to reduce the chance of the riffles being "blown out" should the prime be lost in the main suction hose. An alternative would be to use a 4" power jet mounted directly to the tube, which is how Keene normally did it.

Second, since I used a suction nozzle, I cut the tube opening into the box back far enough to insert the 4" hose into the tube and clamped it down. This shortened the overall length and eliminated a clog point.

Thye entire unit weighs and costs about the same as a 2.5" surface dredge. It burns the amount of gas a 2.5" dredge would, saving more costs and weight.

Recovery issues with a subsurface are simple. The riffle is small, and must be open to capture gold. If you hog material, you will bury the riffle, and lose more gold. If you are getting into gold, check the riffles to make sure they are clearing properly, and then slow up on cramming material through the unit.

These are great unit for hit and run operations where you have coarse gold. If all you have is fine, flaky gold losses may be prohibitive. The longer term the operation, the more gold will be lost over time. For longer term, relatively stationary dredging operations, use a surface type dredge instead.