FUNCTIONAL DESIGN OF GRAVITY RECLAIM STOCKPILES
Gravity reclaim stockpiles are an effective way to store large quantities of material. Our gravity stockpile reclaim designs are engineered based on the measured flow properties of the bulk solid being handled, using in-house developed methods.
Each of our gravity stockpile reclaim designs is based on an expanded flow principle, including mass flow hopper(s) at the stockpile base. This is critical to ensure the required stockpile live capacity and to minimize loads on the feeder.
Our gravity stockpile reclaim designs typically include:
- Gravity reclaim stockpile shape - either conical or prismatic
- Number of hoppers
- Size and geometry of hoppers – shape, angles, outlet details
- Location and spacing of hoppers
- Hopper material of construction for flow and wear
- Feeder design – type, size, speed, power, interface details
- Feeder loads – initial fill, pre-formed rathole, and mass flow
- CAD modeling to provide stockpile live capacity – actual tonnage or percent of total
The result of the functional design of a gravity reclaim stockpile is a dimensioned and annotated drawing. We carefully engineer our gravity stockpile reclaim designs to fit into an existing or new system, all the while ensuring we meet project requirements.
Problem
Due to severe ratholing the live capacity of an existing limestone stockpile was only 7% the total stockpile capacity. This required our client to have stacker availability of > 95%, which was cost prohibitive both in terms of operational costs and maintenance costs.
 Existing prismatic limestone stockpile |
 7% live capacity per stockpile model |
Solution
J&J engineers redesigned the gravity reclaim stockpile configuration, modifying the hoppers and feeders below the gravity reclaim stockpile using in-house developed analytical tools and limestone flow properties. The redesign combined two adjacent hoppers to effectively form a larger hopper. The key components needed to achieve this were the design of a new mass flow hopper, and a tapered belt feeder interface.
 Representation of effective belt feeder interface |
Success in the field
By effectively combining flow channels, the live capacity increased from 7% to 19%. This is a 270% increase, and yields reductions in stacker availability and associated plant costs.
 19% live capacity in modified stockpile |
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 Full stockpile showing gravity reclaim history
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 Stockpile rathole; dangerous practice!
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 Stockpile live capacity modeling
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 Stockpile stacker
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