We have just introduced the new DownDraft mat. Doc
really believes that most people should include this mat in most equipment.
The only ones that may not want to include it are very large dredges. The
DownDraft mat is best used near the end of the sluice system allowing
settling and working for fine gold.
What mat should you use?
probably one of the MOST important pages on this website.
So, take the time to read it please.
Yes, you can screw this up….
We did many times before getting it right and understanding the science.
mats were developed from extensive research which involved a TON of science.
So, not understanding it fully can really cause problems for some. Take the
time to read and understand. If you “get it”…. you’ll see some AMAZING
results. Fine tuning and using the right mats in the right equipment is
should see ½” to about 1” of flow over your mats and at a higher rate of
speed. Tuning in your mat is critical and we address that
HERE as well.
Points from Doc...
1) When ever possible use a
variety of mats in your box. Exposing your slurry / gold to a variety of
surfaces, velocities, and captures zones is the best way to increase gold
recovery of ALL sizes. Repeating the same thing over and over and over
expecting a different result is the definition of insanity. We STRONGLY
believe that offering a variety of mats is the best practice for ALL
2) Don't be a WIMP..... Lose
the fear of losing gold. Most gold is lost not due to FAST water or flows /
velocities being too high, but rather it's due to the fact there is no
ROOM for it. Fine gold often works its way down the sluice because other
materials are filling up the CAPTURE ZONES and not being exchanged out quick
When using our mats the operator should take the mats to empty. Yes, make
EVERYTHING blow out of the mats with super fast water due to extreme pitch.
THEN and ONLY then, start reducing the pitch. Reduce the pitch until you
have a satisfactory capture rate.
The biggest mistake is to start slow and slow it down more due to losses.
In a Water Based Dredge:
Floating or water based dredges have a totally different make up than other
sluice beds. Quite often they use a flare jet which feeds the water directly
into the sluice with no crash box / header box. This creates VERY high
volumes and levels of water in the sluice. You will often see very tall
riffles in these dredges from the manufacture. There is a reason for this.
In other words... even though they have DEEP water, dredge sluice boxes
generally do NOT have high velocities and often the pitch adjustments are
limited. We designed the new RiverHog dredge mat with this in mind. Most
operators will slightly trim the main riffle. Again, testing YOUR box is
key. Most dredges should be outiftted with alternating areas of Scrubber mat
and RiverHog. If you have a 2 stage slucie box, use the Razorback mat in
those areas where flow is quiet.
In a Land Based Dredge:
land based dredges are very similar to a highbanker. The water level is
usually flatter than a water based dredge. In this system all four mats can
be used in combinations. However, if you have a very
large land based dredge or one that is pushing huge volume of water, it may
fall into the same category as the water based dredge.
Most highbankers should use the mats alone. Again, a combination of
Scrubber, Razorback, UR, and RiverHog trimmed, will work well and expose the material to varying surfaces. Most
highbankers allow you to adjust the flow rate and pitch which allows you to
perfectly tune the mats.
In Stream Sluices:
This is a bit tricky. Quite often it is tough to get enough velocity in a
stream sluice. Remember it’s not the VOLUME of water but the velocity /
speed. So being able to get more water and pitch is critical. The Razorback mat was
specifically designed for stream sluices. However, Doc likes to put one or
two pieces of Scrubber in as well.
Every commercial operation is different. If you would like us to review
your plant and op, simply send us the details via the contact page.
Also, see the recommended design layout below. (Click to enlarge.)