McLanahan | Scavenger Systems

How Scavenger Systems Work

Scavenger Systems consist of a Separator, Sump and Pump. They can be installed into any washing or classification process with a waste stream that discharges to a pond. Any stream with desired material is sent to the Sump. From the Sump, it is pumped up to the Separator to capture the desired material, normally in the +200 mesh range. The overflow from the Separator is now the waste stream, and the Separator underflow is directed back into the main system or wherever desired, such as a Dewatering Screen to dry the material for stockpiling.

In a typical Scavenger System, overflow from a Fine Material Screw Washer enters a feed collection Sump, where it is pumped to a Separator that is installed above the discharge end of the screw. The Separator recovers +200 mesh fine sand and discharges it out the bottom of the Separator and onto the screw to discharge with the product material. The overflow from the Separator containing the -200 mesh fine material and water is sent to waste.

Scavenger Systems can also be configured for applications with a Dewatering Screen immediately following the screw. In these configurations, the overflow from the screw enters a feed collection Sump underneath the Dewatering Screen. The material is then pumped up to the Scavenger System’s Separator, which is installed over the Dewatering Screen so that the recovered +200 mesh material is discharged directly onto the screen for further dewatering. 

Why McLanahan Scavenger Systems

For every Scavenger Systems application, McLanahan evaluates the classification process already in place by taking a sample of the waste stream on site and sending it back to McLanahan’s in-house lab for testing. From the tests, McLanahan can determine exactly how a Scavenger System will perform when placed into the process.

Once installed, McLanahan Scavenger Systems benefit an application in two ways. First, they recover material out of the waste stream that would have been destined for the settling pond. Sending less material to the settling pond prevents the pond from filling up too quickly and reduces the frequency of which it needs to be mucked out.

Second, the recovered material is added back into the product pile to increase the amount of salable material while still meeting the required gradation. Additional material in the product pile means additional dollars in your pocket. 

Frequently Asked Questions About Scavenger Systems

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The amount of material you can recover with a Scavenger System depends on the application and how much recovered material can be put back into the product pile without knocking it out of spec. McLanahan will test your material ahead of time to predict how much material you should expect to recover with a Scavenger System while staying within the required product gradation. Even recovering just 5 tons per hour can generate thousands of dollars in additional revenue.

Many applications can benefit from a Scavenger System recovering +200 mesh material from the waste stream to add to the product pile; however, a Scavenger System may not always make sense if recovering material will knock your product out of spec.

That’s why McLanahan tests the material for every potential Scavenger System to see it makes sense for the particular application. With these tests, McLanahan can determine exactly how much material you can recover with a Scavenger System while still remaining in spec.

Systems can be designed to meter in some material and stockpile the other to be used at a later date, for a different product or just to eliminate settling pond buildup.

Scavenger Systems do not typically require any additional water, as they process the overflow from the screw. However, for some applications, makeup water may be required to maintain or balance the sump level.

The amount of horsepower required to operate a Scavenger System depends on the size of the Pump selected. The Pump is the only part of the system that uses power.

No, you cannot eliminate your settling pond by using a Scavenger System, but you can reduce pond cleanout frequency and the hassle that goes with it. While Scavenger Systems recover +200 mesh material from Screw Washer overflow to reduce the amount of solids reporting to the settling pond, they still produce a waste stream of -200 mesh fine material and water that needs to be sent to a pond or downstream processing equipment.

If completely eliminating settling ponds is your goal, consider a Thickener, Centrifuge or Filter Press.

McLanahan Scavenger Systems can be added to any washing or classification process with a waste stream.

Features & Benefits
  • Recover +200 mesh material from the waste stream
  • Reduce amount of solids reporting to settling ponds
  • Prevent ponds from filling up too quickly
  • Reduce pond cleanout frequency
  • Generate additional revenue by adding more material to product pile

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