Well, the effect of bouyancy is caused by the displacement of water.

If you have a tank of water and you hold a ball under the surface of the water and let go, 1 of 3 things can happen.

1.Nothing. If the ball's weight is exactly equal to the weight of the water it displaces (i.e. its own volume of water), the ball will stay in the same place.

2.Float. By archimedes' principle, the amount of upthrust experienced by an object is exactly equal to the volume of water it displaces. If the ball's weight is less than the weight of water it displaces, the upthrust will be greater than the weight and the ball will float to the surface. Once at the surface, the proportion of the ball which is submerged will depend on the weight of the ball- the water displaced by the ball while floating will be exactly equal to its weight.

3.Sink. If the ball is heavy enough, the upthrust will be less than the weight and the ball will sink.

Therefore, using archimedes' principle for a mud slurry, the liquid will be far denser than water and so, every 1 cm^3 displaced will generate a greater amount of upthrust than 1 cm^3 of water.

So, to answer your question, the bouyancy will be far greater in mud than in water.

"I have great faith in fools; self-confidence my friends call it."

-Edgar Allan Poe