Dredging World News Blog

Isaiah Helm

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Plug and Play Dredging: how to Move Sediment to the Drying Bed

Posted by Isaiah Helm on Mon, Jun 08, 2015 @ 09:06 AM

Got a minute?  Watch a one minute video of the plug and play SD-110 Rotomite dredge in the Philippines.

"Plug and Play" is a catchphrase of USB computer gadgets, representing equipment that can be connected to a system and used immediately.  No system configurations;  no drivers;  no troubleshooting compatibility.  In the modern world of plug and play, rapid system deployment is more than a feature - it's an expectation.

The dredging world is subject to these same expectations. For example, in the Philippines, a city water plant had settling ponds filled to the brim with sediment. The low capacity severely restricted their ability to process water. The solution was a “plug and play” dredge: the Rotomite SD110 from SRS Crisafulli, Glendive, MT.

A self propelled diesel dredge excels in rapid deployment. No need to configure for foreign electric standards. No need to install a cable traverse system or run three phase power lines. No need to rotate or side shift a floating dredge that’s encased in mud on both sides and can only excavate material in a straight line in front of it. 



 Image 1: Water plant settling pond full of sediment, Maynilad Water Services, Manilla.

The Rotomite SD110 can float in 17 inches of water and turn as it dredges. A spinning propeller in shallow water stirs up a lot of mud. Muddy water is a cancer to water cooled outboards but has little effect on the SD110’s sealed hydraulic thruster. Paddle wheels seem like a natural choice in shallow situations, but their bulk outweighs their effectiveness. Turning a long dredge body with paddles is cumbersome, and in deep, soft mud any added traction will be lost in added drag.  The SD110 gets 500lb of thrust from a 12 inch prop assembly, which can quickly apply full power in forward or reverse in a 180 degree arc. The result is excellent maneuverability, even when pushing against mud and dragging along a floating pipeline.


All these features were critical at this Philippine site. The sludge was destined for drying beds south of the pond, so the logical approach was to start dredging on the south side. Production is best with a shorter pipeline. However, the only spot with even a token water depth was by the pond’s north end intake. The dredge would be inserted with mud on all sides and any movement would have to be in a canal of its own making.


 Image 2: Rotomite SD110 floats in the pool it has excavated, first day Dredging

Floating discharge line was connected to the SD110 before the crane picked it up, and dredging began the moment it set down. Due to the water shortage, the discharge was dumped back into a different section of the pond. That allowed solids to settle out and water to run back and fill up the hole being excavated. Within a few hours enough material was removed to let the dredge turn in any direction and dock up against the shore. One day later, the SD110 had channeled its way to the south shore and had begun filling the drying beds.







Topics: water treatment plant

Mine Restores Basin Capacity with Hydraulic Dredge

Posted by Isaiah Helm on Tue, Nov 18, 2014 @ 12:11 PM

SRS Crisafulli introduces the Rotomite model 6000-CD Dredge

SRS Crisafulli designed and built the self-propelled, steerable, diesel powered all-purpose dredge for both abrasive and soft slurries with a cast alloy pump, and 8” discharge, in the fall of 2013.  The dredge was tested at Fisher Sand and Gravel’s pond on Circle Highway northwest of the Company’s Glendive, Montana manufacturing plant, just before winter set in.


Photos:  R6CD dredge testing at Fisher Sand and Gravel, Glendive MT, 2013

2014 Job Site

During the winter, the SRS Crisafulli Dredge Sales and Rental Department worked with a copper mine in the American Southwest on a Dredge Rental contract. The mine needed to restore their basin capacity without stopping mine processes, which is the perfect application for hydraulic dredging.

Dredge Application:

Problem: The customer has a plastic-lined tailings dam that collects outflow from various processing facilities. The mixture is generally acidic, with lye added to balance ph levels. A floating pump transfers water and material from this small catch basin into a very large permanent tailings impoundment. The limited ability of the floating pump to pull in slurry led to a build-up of solids, which reduced the pond’s holding capacity.

The customer wanted to restore this capacity to original levels without stopping any mine processes or damaging the liner.

Solution: The new SRS Crisafulli Rotomite model 6000CD was selected for its ability to handle abrasive tailings materials. The Rotomite 6000CD also proved to be well suited for pumping through 500 ft. of 8 in floating discharge pipe, 1500 ft. of 10 inch fused pipe, and over an 80 ft. berm at 1300-1500 gpm. No booster pump was required, reducing cost and complexity of the system. The cutterhead was outfitted with a liner protection cage, preventing its horizontal auger from damaging the liner as it pushed slurry into the pump. This cage restricted the auger from digging into settled solids, so SRS Crisafulli’s unique cutterhead articulation became indispensible as the primary method of breaking up material.


The hydraulic thruster on the back of the Rotomite 6000CD was also a critical component. Both the perimeter and floor of the basin are irregularly shaped, and it is surrounded by a fence, making cable positioning difficult and cumbersome. The thruster’s 180 degree range of motion and hydraulically variable depth allowed quick and easy positioning of the dredge during operation and docking.

The project began with an estimated 76,000 cubic yards of material to be removed.  A satisfactory quantity of tailings was removed to restore the impoundment’s capacity.

Thanks to the SRS Crisafulli dredge rental program, the copper mine’s project was completed in less than six months.


The inaugural season of the R6CD was a great success.

Please call the offices to schedule a rental for 2015, or inquire about an equipment purchase.



Topics: dredging equipment rentals, Hydraulic dredging, Tailings Dam, Rotomite 6000CD