Gold Tailings transportation

[SIAUPA]

Hello everyone,

We design a piping trasportation system for the TSF (Tailings Storage Facility).
Slurry : Gold Slurry Rougher Tails
Liquid: process water
Slurry temp: 5-20C
Design flow rate: 511 m3/hour
% solids: 32%
SG slurry: 1.25
Slurry velocity: 2.36 m/s

We will use 315mm OD, HDPE PN10, twin pipes to transport the slurry (tailings) over 1.6 km over a hill (no data on latitude yet)

Climate: cold weather -35C to -38C
Project is in a part of Russia where an accidental shut- downs are very likely to happen anytime; the preventive maintenance very poor.

Is insulation of the HDPE pipes required?
Please, reason your answer.

Thank you in advance for your time.

 

[cvg]

511 m3/hour per pipe? or total for both pipes?

is the pipe above or below ground?

if below ground, how deep?

if above ground, insulation is recommended since once the pipe freezes you could be out of commission until spring. However, insulation alone will do very little good if you have a protracted shutdown, it will freeze solid anyway. What is your plan for thawing the line?

 

[Artisi]

Has anyone calculated the pump discharge pressure as yet compared to the pressure rating of the HDPE pipe line?

 

[micalbrch]

I just tried, Artisi. Around 9 bar (130 psi) which would fit to the PN 10 pipe. I assumed a viscosity of 150 cP and a static head of 15 m. 511 m³/h through one pipe. Otherwise the velocity will not match. So, that's o.k. and the flow is turbulent which is important for tailings transfer.

I'm not sure if insulation alone is sufficient. -35 to -38 °C under extreme conditions means the water will freeze as soon as the system stops. So, I guess you need pipe heating.

 

[SIAUPA]

Thank you all very much, especially micalbrch.
Yes, I concluded the heat tracing is a must. The project is in Kyrgyz Republic (one of the former comunist country); the power failure is very likely to happen and to last; yes, we will flash the tailings immediately, but in that part of the world "immediately" has a different meaning. Unfortunately I shall gather all the good arguments to convince people in charge that heat tracing/ electrical tracing is required and to get their approval.
Thanks again.