1. . 
A mud that contains commercial weighting material such as barite or hematite. The economic difference in weighted and unweighted muds is the cost of replacing weighting material according to the solids control practices used. Solids control techniques, such as dilution or hydrocycloning, that can be economical in unweighted muds are not necessarily economical for weighted muds, although centrifugation (incorrectly called "barite recovery") is typically performed when using weighted muds to control mud viscosity.
Antonyms: unweighted mud