A rising slurry density is a warning that the working fluid is becoming different from the fresh fluid. The cause may be coarse sand, fine silt/clay, rock fines or an incorrect fresh formulation.

Start with the fresh baseline

Record fresh density before excavation. If the fresh batch is already high, review actual tank volume and product quantity before blaming the formation.

Use sand content to split the diagnosis

High density + high sand suggests coarse-solids loading and mechanical separation. High density + low sand suggests fine solids that may require finer separation or fluid exchange.

Polymer systems

Because fresh polymer contains little mineral solid, density is especially useful. A passing Marsh value does not cancel a rising density trend.

Bentonite systems

Compare working ALKABEN slurry against its own fresh baseline. Do not add more bentonite to a high-density dirty slurry unless a true formulation deficit is demonstrated.

Surface vs bottom

Bottom density can be much higher than surface density. Record sample location and use the project-required pre-concrete sampling procedure.

Frequently asked questions

Can dilution reduce density?

It can lower the number but does not remove the solids.

Can a desander reduce density?

Yes when coarse sand is a major contributor. If density remains high afterward, fines likely remain.

Should polymer be added because density is high?

No. High density usually indicates contamination, not insufficient polymer.