Angle of Repose for a Fine Tailings Potash Slurry

[Unusednamehere]

I was just wondering if anyone knew what a good approximate angle of repose for a potash fine tailings slurry that will be deposited with a 35% solids by mass. These tailings consist of 59% silt and 41% Clay.

 

[Ron]

less than 10 degrees

 

[Unusednamehere]

Would assuming a slope of 2.5% be a conservative estimate?

 

[dgillette]

I don't think "angle of repose" is the correct concept to be working with here. Depending on the activity of the clay, you may be better off thinking in terms of viscous fluid of the Bingham type (non-Newtonian, nonlinear), or of undrained shear strength of very soft clay. Angle of repose is generally associated with dry granular materials like sand, gravel, or wheat. Here, 35% solids -> WC=186%, which for most materials (not all!) is much wetter than the liquid limit.

Unusednamehere - is your handle like He Who Must Not Be Named in the Harry Potter books?

 

[mudman54]

2.5% seems low, but you need to tell us if it is drained

 

[Unusednamehere]

Sorry, I should say more like angle of deposition. This slurry will be a non segregating batch, so initial deposition i think we can assume it will be undrained (not too sure on this), then it will be given ample time to dry out before another lift will be deposited on top of this.