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Mt Rosser Pond
Pumping Soft, Thixotropic Red Mud With an Excavator-Mounted 4″ EDDY Pump
When bauxite red mud too soft to carry any earthmoving equipment had to be moved to regrade Mt Rosser Pond, Rio Tinto Alcan trialed an excavator-mounted 4″ EDDY Pump — which pumped the in-situ mud at 21–52 l/s (332–824 gpm), close to its natural 42% solids content.
FIELD TRIAL CASE STUDY
A field trial showed that a 4-inch EDDY Pump could move bauxite red mud so soft that no earthmoving equipment could cross it — pumping it close to its in-situ solids content.
Mt Rosser Pond is a 40-hectare bauxite-residue (red mud) tailings dam in Jamaica’s Diablo Mountains, in service from 1959 until 1991. Its remediation calls for moving about 500,000 m³ of mud up to 1 km to regrade the surface so it can drain, stabilise, and be vegetated. But the surface muds are so soft — shear strength under 3 kPa — and so thixotropic that they liquefy under load, leaving them inaccessible even to modified earthmoving equipment. Rio Tinto Alcan commissioned a trial to test whether the in-situ red mud could instead be pumped.
PUMPED CLOSE TO THE MUD’S IN-SITU SOLIDS CONTENT
MUD-PUMPING RATES ACHIEVED WITH A 4" PUMP
SURFACE SHEAR STRENGTH — TOO SOFT FOR EARTHMOVING EQUIPMENT
The Challenge: Red Mud Too Soft for Earthmoving Equipment
The muds at Mt Rosser are a high-plasticity clayey silt with very low shear strength, 1 to 6 kPa, under 3 kPa at the surface, and a bearing capacity below 20 kPa. Because they are thixotropic, they rapidly liquefy under vibration or shear, so conventional earthmoving would have needed extensive “floating” haul roads, with a high risk of losing machinery and endangering personnel.
Red mud is normally pumped at 30% solids or less, then left for years to reconsolidate. Here the goal was different: pump the mud close to its in-situ moisture content, 137%, about 42% solids, to move roughly 500,000 m³ up to 1 km. A parallel test filled geotubes to see how well they contained and dewatered the pumped mud.
The Solution: A 4-Inch EDDY Pump Trial on Rio Tinto's Mt Rosser Pond
- 4" EDDY Pump with hydraulic drive and cutter head, mounted on a JCB 220 excavator boom
- Excavator hydraulics powered the pump (30–40 gpm at 3,500–4,000 psi); a standalone power unit drove the cutter head
- Long-reach CAT 325 (60-ft boom) loosened and moved the muds toward the cutter head
- Recirculation mode primed the pump and agitated the mud before discharge
- Cutter head upgraded on site with welded “stirrers” and a “comb” so it wouldn’t blind with mud
- Discharge through 30 m of flexible hose and 60 m of 4" HDPE pipe onto the mud beach
Red mud so soft that no earthmoving equipment could cross it — shear strength under 3 kPa — was pumped close to its in-situ 42% solids at rates of 332 to 824 gpm.
MT ROSSER POND MUD-PUMPING TRIAL · RIO TINTO ALCAN, JAMAICA
How Eddy Pump Technology Works
At the core of the EDDY Pump is a geometrically designed spinning rotor, not a centrifugal, positive-displacement, or vortex pump, that harnesses the principles of a tornado to create a synchronized eddy current. With the rotor out of the flow stream, it moves high and variable percentages of solids and passes lumps and debris that would clog conventional pumps.
That robustness is exactly why a 4-inch EDDY Pump was chosen for material this difficult. On site, the cutter head was fitted with welded stirrers and a comb to keep it from blinding, letting it agitate the lumpy, high-plasticity red mud and pump it close to its in-situ solids content, where conventional equipment couldn’t even reach the surface.
The Results: 332–824 GPM at Near In-Situ Solids Content
- Pumped the red mud at 332–824 gpm (21–52 l/s), close to its in-situ ~42% solids
- Filled three geotubes that dewatered substantially — about 30% volume loss in six weeks, raising solids toward ~53%
- Geotubes proved effective for building a small containment dam; the ponded mud behind them firmed and cracked as it dried
- Mapped the full-scale requirements: a larger, pontoon-mounted, remotely controlled pump; a priming method that doesn’t rely on surface water; stronger agitation (200–400 rpm); and a step-up 6" discharge line to cut friction loss roughly tenfold
- Confirmed the scale of the works; moving ~500,000 m³ would take on the order of one to two years, pointing to a larger pump and/or in-line booster for the full job
About The Mt Rosser Pond Project
Mt Rosser Pond is a 40-hectare bauxite-residue (red mud) tailings dam in the Diablo Mountains of Jamaica, built in 1959 and used until 1991. As part of Rio Tinto Alcan’s excluded-assets remediation, the site is being regraded so its mud surface can be stabilised and vegetated — work that requires moving roughly 500,000 m³ of very soft red mud up to a kilometre across the pond.
About Eddy Pump Corporation
Founded in 1984, EDDY Pump Corporation delivers breakthrough technology and service to industries including the U.S. Navy, oil & gas, mining, wastewater, paper/pulp, dredging, fracking, and chemical. At its core is the patented EDDY Pump — not a centrifugal, vortex, or positive-displacement pump, but a geometrically designed spinning rotor that harnesses the power of a tornado into fluid dynamics, handling material once deemed impossible or cost-prohibitive.