A falling slurry level is a symptom. The fluid may be filtering into porous ground, penetrating coarse gravel, entering fractures or disappearing into a void. Those mechanisms should not receive the same treatment.

Measure the loss

Record make-up volume in m³/h and the depth where loss starts. A loss that decreases with time can reflect developing retention; a persistent severe loss with qualified slurry properties points toward a structural pathway.

Filtration

For ALKABEN systems, optimize the mineral support/filtration behaviour. MUDOPAC LV or HV may be evaluated when laboratory/field evidence shows filtration is the missing function.

Whole-fluid loss

Open gravel, fractures and cavities can accept the complete slurry. PAC, more bentonite or more polymer should not be presented as unlimited bridging solutions.

Operational limit

Compare loss rate with clean-slurry production rate and ready reserve. If the site cannot maintain required head, the support system is operationally unsustainable and an engineering intervention is required.