Morrison Mud's EPB and muck pumping treatment guide

Note: This table exclutes muck types such as soft, paste-like clay and chalk mixtures which are not very sticky and provide classic "toothpaste-like" EPB behaviour and generally do not require additive treatment.

If you have any comments ot queries on this information, or if you require advice about specific ground conditions, please contact us.

Ground type

Mining characteristics

Recommended treatment

Pure, plastic and smectitic (swelling) clay

Actually cut quite easily - but can stick back together again in the chamber, and does not flow well

Apply TKF foam at 3% 5% solution and 2 to 3 times air expansion. Injection rate: up to 1 litre of TKF solution per 10 litres of in situ clay.

Laminated, silty, sandy, and impure clay

Breaks up more easily. May not form effective plug unless wet. May be sticky. May be abrasive. May resist flow.

TKF foam injection at 3% to 4% solution and 1 to 3 times air expansion will improve advance rate.

Clayey sands and gravels

Will behave in a generally clay-like manner if clay content is over 10%. Torque, wear, and flow problems may arise.

Try TKF foam as above to optimise EPB behaviour. Add TK60 polymer (at 0.3% of foam solution) to improve librication and plug forming.

Silty fine sands

May flow and form plug. plug may be too weak to prevent water influx

Inject TKF Foam and TK60 Solution to head to homogenise and stiffen muck and reduce abrasion if required. Inject neat TK60 to screw if plug is required.

Clean sands and gravels

Tend to mass and lock up in head. Tend to produce high torque. No waterproofing.

Inject TKF/TK60 combination foam, or just TK60 polymer solution, to head and face to improve workability. If necessary, inject TK60 Polymer to screw to form plug.

Cobbles and boulders

Tend to congregate in clumps in head and screw causing jamming. No waterproofing effect

Add TK60 solution at 1% to form lubricating gek; or MX or MX Liquid gel to pr0vide plud flow and suspension.