Linerless Chute

Posted in: , on 22. Jan. 2008 - 02:54

Dear all,

Has anyone out there had experience with linerless chutes.

The basically contain a number of small rock boxes in succession.

I am interested in hearing about where they have worked well and where they have been a disaster.

I would be most interested in hearing about -150mm Iron Ore and whether these chutes did indeed eliminate the need for liners.

I realise these chutes will not work on high clay (sticky) iron ore. Is anyone able to quantify the limit? eg throw the fines and see if it sticks??

Best Regards,

Gareth Blakey

Best Regards, Gareth Blakey
(not verified)

Linerless Chutes

Posted on 22. Jan. 2008 - 02:35

Mr. Gareth Blakely.

It can work particularly in big open areas with steep faces but wet fines will always be a problem in narrow throats even at steep angle.

Need to know more about the equipment you are trying to protect + geometry of the chute etc.


Eric Olsen

Lintec Engineering (Pty) Ltd.

South Africa

Re: Linerless Chute

Posted on 22. Jan. 2008 - 05:06

Dear Sir:

As Mr. Blakely points out, more information is needed. Rock boxes in succesion are a very effective way to control wear because the material builds up avoiding the need to install liners on the area covered by the buildup. However, the design could be complicated. The boxes plus the build up reduce the crossflow area of the chute and possible backflows could occur if high flow rates are to be expected. In addition to that, the angle of buildup would depend on the particular characteristics of the ore you process such as the particle size and the percentage of clay present.

Boxes too far appart could leave portions of the chute unprotected. Boxes too close together could prove to be more expensive than lining the whole chute (it greatly depends on the geometry).


Enrique Boada Sales Manager Colombia Corrosion Engineering Inc. Tel: 57-1-8625149 Cel: 57-313-2836864 E-mail: Website:

Re: Linerless Chute

Posted on 22. Jan. 2008 - 06:08

We use step chutes (rock boxes) all the time. We use them with furnace coke, cinter, ore, slag, clinker etc.. Can't use where there are alot of fines present or high moisture. We use them with the clinker that is high in fines but has almost no moisture. For furnace coke we found that lining our chutes with Wearmax was a better solution lasting 5-10x longer than stainless, rockboxes slowed down the material too much even on a steep incline.

Re: Linerless Chute

Posted on 24. Jan. 2008 - 12:07

In its ultimate form what you are describing is the Weba chute. They do work well in some applications but they also require rebuilds. The frequency depends on the ore, with -150mm iron ore my guess is every 12 months. If you want to avoid such re-builds but use the same consept to control the material speed then you have to have your trajectoiries done accurately, there must be no cohesive material (eg wet fines) to consider and you basically have each step set up as a mini autogeneous rock box.

The concepts have merit but also have their downsides as far as expense in building plus life cycle costs. Material flow control can be very good.


Col Benjamin

Gulf Conveyor Systems Pty Ltd

Re: Linerless Chute

Posted on 29. Jan. 2008 - 08:13

Yes what I am describing is pretty much a Weba chute.

There is some clay content and the fines do get sticky. Moisture content can be up to 5%.

I am having testing done to determine internal and external friction angles for various moisture levels.

I have a good understanding of how to use these values to design lined chutes but I am unsure how to use these values to rule out the use of rock boxes.

eg if the rock box slope is greater than internal friction angle I would guess that the product should flow.

Is the rock box slope = to the angle of repose for the material. Does the geometry of the ledges affect the rock box slope? Does the impact angle affect the rock box slope?

Any experience with this would save me a lot of trial and error.

Best Regards,

Best Regards, Gareth Blakey

Linerless Chute

Posted on 30. Jan. 2008 - 08:01

At Dos Santos International we had the pleasure of selling the first WEBA chute in North America, a cascade type. The cascade design uses closely spaced internal shelves, or terraces, that fill with the transferred material. In a short time the material compacts between the shelves and serves as the wear surface.

The Weba chute, installed in the USA Gulf Coast handles coal at very high volumetric rates, to 9000 t/h. The material varied from dry to wet, depending on the conditions at the open reclaim yard or at the bottom of the barges that are continuously unloaded. There is no shortage of fines. This transfer is very successful.

Joe Dos Santos

Dos Santos International 531 Roselane St NW Suite 810 Marietta, GA 30060 USA Tel: 1 770 423 9895 Fax 1 866 473 2252 Email: jds@ Web Site: [url][/url]

Linerless Chute

Posted on 19. Feb. 2008 - 12:17

Dear Sir,

I did linerless chute in coke handling system. I did stone box system for all the chutes, coke being very abrasive material.



Linerless Chute

Posted on 19. Feb. 2008 - 06:35

Mr. Banerjee,

I too had used rock box transfers to reduce wear. A WEBA Cascade chute is much more sophisticated in controlling the material flow through the chute so that the material will neither speed up nor slow down excessively. The terraces are closely spaced and, when packed, the chute behaves like a rough lined chute. The shelves have provision for initial field adjustment. The material flow is so well controlled onto the outgoing belt that typical transfers are without skirts.

Joe Dos santos

Dos Santos International 531 Roselane St NW Suite 810 Marietta, GA 30060 USA Tel: 1 770 423 9895 Fax 1 866 473 2252 Email: jds@ Web Site: [url][/url]