Yuba Mining and Machine
Placer Gold Recovery
Mobile, High-Recovery Processing for Alluvial Gold Deposits
Placer deposits are rarely concentrated in one convenient location. Gold-bearing sand, gravel, and clay may extend along an old river channel, across a floodplain, or through multiple layers of an alluvial deposit. As mining advances, operators must continually decide whether to haul material back to a stationary plant or move the recovery equipment closer to the active excavation.
Yuba Mining and Machine’s mobile placer recovery systems are designed around a simpler approach: move the plant to the material instead of repeatedly hauling the material to the plant.
Our Mobile Placer Plants and Mobile Scrubber Trommel Plants combine washing, classification, primary concentration, onboard power, and water handling on towable plant frames. This allows the recovery circuit to advance along the deposit as mining progresses, reducing unnecessary truck travel, fuel consumption, material handling, and site congestion.
The plants can be repositioned in under an hour using their built-in leveling jacks, making them suitable for both production mining and exploration work where the active mining area may change regularly.
The Challenges of Placer Gold Mining
Placer mining is not simply a matter of running gravel through a recovery machine. Successful recovery depends on properly preparing the material before it reaches the concentrator.
Common challenges include:
Moving Large Volumes of Low-Grade Material
Placer deposits often require processing large volumes of material to recover a relatively small amount of gold. Hauling every bucket of gravel to a distant stationary plant can become one of the largest operating costs on the mine.
A mobile plant can be positioned near the active cut, reducing haul distance and allowing excavators or loaders to feed the plant directly.
Variable Sand, Gravel, and Rock Sizes
Run-of-mine placer material may contain everything from fine sand to large cobbles. Oversize rock must be separated from the smaller gold-bearing fraction before concentration.
A wet feed hopper and classifier remove oversize material while allowing the properly sized slurry to move into the primary recovery circuit.
Clay-Bound Gold
Clay can hold together in dense balls or coatings that trap fine gold particles. Unless the clay is thoroughly broken down and liquefied, the gold may remain locked inside the material and pass through the plant without being recovered.
This is why selecting the correct washing system is critical.
Fine Gold Recovery
Coarse nuggets are relatively easy to capture. Fine and flour gold are more difficult because they can remain suspended in process water or travel with lighter sand.
Our placer plants use the Low-G Horizontal Centrifuge as the primary concentrator, and we recommend Reverse Multi-Helix Spiral equipment for secondary recovery, cleaning, and finishing.
Choosing Between the MPP and MSTP
The most important factor when selecting a mobile placer plant is the washing characteristic of the deposit, particularly its clay content.
Mobile Placer Plant: Best for Free-Washing Material
The Mobile Placer Plant, or MPP, is designed for traditional river-channel placer deposits consisting primarily of:
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Sand
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Gravel
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Cobble and stone
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Free-washing alluvial material
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Low-clay feed
The vibrating wet feed hopper and screen deck wash and classify the material before it enters the
Low-G Centrifuge.
Because the MPP uses a screen-deck classification system rather than an aggressive scrubber, it is lighter, more compact, and easier to relocate around the mine site. It is the preferred choice when the gold-bearing material breaks apart readily under normal water spray and agitation.
The MPP provides only limited scrubbing action and is generally not recommended for deposits containing more than approximately 25% clay.
Best suited for:
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Traditional river-channel placers
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Free-flowing sand and gravel
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Low-clay deposits
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Operations requiring frequent plant movement
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Exploration and bulk-sampling programs
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Sites where a smaller operating footprint is important
Mobile Scrubber Trommel Plant: Best for Clay-Rich Material
The Mobile Scrubber Trommel Plant, or MSTP, is designed for clay-rich and mixed alluvial deposits.
These deposits may contain:
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Sticky or compacted clay
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Sand and gravel mixed with clay
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Weathered alluvial material
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Gold encapsulated in clay balls
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Variable material from multiple deposit layers
The scrubber trommel provides more aggressive washing than a conventional screen deck. As the material tumbles through the rotating drum, water and mechanical agitation break down clay, release trapped gold, and classify the material before it reaches the concentrator.
The MSTP is larger and heavier than the MPP, but it can process a wider range of placer material and is the appropriate choice when effective gold recovery depends on thoroughly scrubbing the feed.
Best suited for:
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Clay-rich placer deposits
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Mixed sand, gravel, and clay
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Old alluvial terraces
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Valley and sedimentary deposits
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Material containing compacted clay balls
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Operations with changing or uncertain feed conditions
Simple Selection Guide
Deposit characteristic
Recommended Plant
Clean, free-washing sand and gravel
Traditional low-clay river-channel placer
Frequent relocation is a priority
Sticky or compacted clay
Gold may be trapped inside clay
Mixed or highly variable alluvial material
Build the Plant Around the Deposit
No two placer deposits wash or concentrate exactly the same way. Clay percentage, gold particle size, water availability, feed size, production goals, and site access all influence the correct plant configuration.
Yuba Mining and Machine can help evaluate your material and recommend an MPP, MSTP, or custom recovery circuit based on:
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Deposit composition
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Clay content
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Expected gold size
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Required production rate
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Available water
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Site mobility requirements
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Final concentrate goals
The MPP is the preferred solution for low-clay, free-washing placer deposits. The MSTP is the appropriate solution when clay must be aggressively scrubbed to release the gold.
Both systems are designed to bring the recovery plant closer to the ore, reduce unnecessary hauling, and provide a complete mobile gravity recovery process from raw material through final concentrate.