More information is required:

1. tonnage of each

2.transfer chute design

3. internal friction angle ( limestone and gypsum mixed frict coef)

4. belt surface friction (wall friction coef)

5. particle size mix

It would appear you can handle about 2000 tph. Much more than this will aid spillage.

Gypsum has much lower internal and surface coefficient of friction than limestone. If it has a fines content, it will act as a lubricant between lstones.

You must determine which condition is causing you backwash:

(Note: it may be a combination of the three below)

1. transfer station has loading with vertical flow causing the apparent belt surface friction to be reduced - requires the vertical flow to be directed more in-line with the 12 degree belt slope.

2. belt surface friction is exceeded - can be aided with a chevron or other raised belt surface.

3. material internal friction angle is exceeded by the slope with idler roll agitation contributing - may need to covert to a pocket or flexowall type conveyor

There are other methods to aid controlling the backwash. We try not to speculate and so say more info is needed.

Other factors may also contribute. WIthout more information, no

can do. ■