WATER SPEED IS CRITICAL...
Remember what football coaches use to say? "Eat a big steak before the
game." We now know that is totally incorrect. As research is done, science
is applied, we learn more and more. The same applies to recovering gold.
It's Not Magic....
Our year of research had it's ups and downs. However, we quickly learned
that when you apply SCIENCE... not opinions, or folklore, things start to
work. You must take the time to understand the science, not only of our
mats, but gold recovery overall.
Our mats are designed to ACTIVELY AND RAPIDLY exchange material based on
their weight / specific density. The "battles" the mindset of HOLDING
material. Most people, including us sometimes, don't get their mats active
enough. Therefore the exchange is slow and we have gone back to the "holding
theory". Water Speed and Velocity...
The mats become active with high water SPEED, which is different than
volume. Remember, you can run 8000 gallons hour through your sluice at a low
pitch and the water SPEED will be very low. The mats will NOT be active just
by adding more water VOLUME. Increase the pitch / angle and you'll see a
HUGE difference. Water will race down the sluice giving the mats ENERGY and
making them active. Dancing Particles...
When looking at your mats, you should see HYPERACTIVE dancing particles.
Now, did we say the are jostling around? No, we said HYPERACTIVE. They will
be rapidly dancing around and look like they are about to be pulled out of
the mat. That is the point where a good exchange rate is occurring.
It's All About Playing...
Test your settings and use EXTREMES. Go WAY too fast, and WAY too slow.
Don't try and hit it perfect. Slowly adjust your setup until you find the
best exchange and recovery rates.
We have started this page to help with the many questions we get on using
the mats and sluice bed setup in general. It will be growing daily, so check
back as we answer your questions here.
What should the Scrubber Mat look like when running properly.
Click on the image below to expand...
(It will open in a new window.)
Installing in Dredges
Smooth Swim / Flood Effect Excessively high water volume / depths
in your sluice box.
We really didn’t cover a great deal on this during our
research but felt we should cover it for the few that might be impacted.
This gets a little tough to grasp, so we’ll walk you through it.
The smooth swim effect / flooding, is when water levels /
depths get too high in sluice bed in relation to the riffles or sluice bed
capture devices on the bed. (This includes our matting.)
From the picture / diagram on this page you’ll see various
water “levels” in the sluice bed. The “swim effect” (flooding) happens
when the LEVEL of water is too high in relation to the riffles installed. We
most often see this in DREDGES that have little control over water FLOW or
volume of water.
When this swim / flood effect happens you’ll often see the surface of the
water in your sluice box “calm down”. This has many impacts but the most
significant is on your sluice BED / bottom of your sluice.
I will try and explain by building a picture in your mind.
First, imagine a stream that has nothing but medium size rocks
on the bottom.
The normal flow for this stream is few inches over these rocks.
As the water flows over this rock bed, you can see how the rocks impact the
flow. You see gentle waves, curves, ripples, and general distortions of the
water’s surface. If you look closely you find that water at the bottom, on
the rocks / touching the rocks, has a strong flow.
Now, let’s flood the stream with a large VOLUME of water which
increases its depth 4 times the normal. What happens to the surface of the
water? The surface of the water now “smooths” out. The increase depth /
volume of water has made the rocks on the bottom less of a factor and their
impact is reduced significantly. Often this will also reduce the water
SPEED / velocity at the stream bottom as well.
This is why you will often see LARGE riffles in a large dredge
/ sluice bed, and smaller ones as the water volume / depth of water is
reduced. Putting ¼” mini riffles in a large dredge sluice bed that has 2 –
3” inches of water depth would create little WORKING action. This would
allow the SWIM EFFECT to occur. Even though heavy material might sink to the
bottom, there is little working action to HOLD it. There is often very
little or reduced differences in pressure zones, ie: behind riffles, to
separate materials based on their weight / specific density.
does this relate to our mattings?
For most sluice or highbankers it really doesn’t. You can control the flow,
depth, pitch, etc, and create the perfect action.
However, if you have a high volume dredge, where it is difficult to control
water flows, volume and depth, then we suggest you keep your current riffles
and use the UR mat with ½”expanded metal over it. Removing 2” or 3” riffles
and putting in only Scrubber mat might actually cause the above swim / flood