Sir,

Aerial ropeways as I understand it are a thing of the past. One of our cement plants has an aerial ropeway from the mine to the plant becasue of the steep incline out of the mine.

Aerial ropeways have spillage at the loading point and have high maintenance issues with the bucket gate mechanisims. To provide the capacity, U will need a lot of buckets and when all of these require maintenance, U will have huge costs!!!!!

The best option is belts.

James Morrish ■

Dear Shri G Ravindra,

Mr. R J Morrish has given considerate opinion / information. In brief, I can only say the following :

1) If the terrain is very hilly and difficult, with many ups and downs, the aerial ropeway may be the only solution and will be suited for the application.

2) One cannot easily temper / damage the aerial ropeway system. The belt conveyor system needs certain level of security. It may not be safe in a totally desolate place. It is possible that the people can damage, steal the components or even steal the material if it is like coal.

3) Present practice is to opt for belt conveyors wherever the same are feasible. This practice might certainly have arisen from the experience of various users and people. However as said earlier there are certain areas of applications where ropeway will be more economical solution. Possibly, ropeway will have capacity limitation whereas belt conveyor of any practical capacity is feasible.

4) The belt conveyor will generally need some kind of road along its length for inspection, maintenance, etc.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

Sirs,

I have a similar problem to G Ravindra. My company is about to commence a Feasibility Study on a base metal mine in a mountain location. As a part of the Feasibility Study we need to give guidance to our engineering contractors on our preferred means of transport of crushed ore from the primary crusher at the mine down to the main plant site, around 2km and 450m descent away.

The annual rate to be moved would be 800,000 tonnes, or around 95t/hour. (based on 24hrs/day for 350 days/yr)

I suspect that a conveyor system will not work due to the gradient and tight bends. A slurry system is not viable as water is in very limited supply, and I am starting to see that an Aerial Ropeway although 'old' technology is perhaps the most viable solution.

Does anyone have experience of these in a modern day setting? In particular I am interested in typical unit capital costs per kilometre (perhaps you have experience of these from a previous project) and in identifying potential suppliers, who are proving difficult to find.

I would be grateful for any ideas.

Many thanks,

Brett Grist ■

G. Ravindra & Brett Grist,

Although much depends on the terrain, you should check on the possibility of using Imperial Technologies Multi-Fold conveyor system. They have an application in Nevada, USA that involves a very steep decline.

General information on this conveyor type can be obtained via their website www.imperial-technologies.com and specific inform can be obtained by discussing your needs with them.

Generally, arial ropeway systems are more expensive to run (especially with higher maintenance costs) than belt systems.

Good luck with your evaluations. ■

Two other suppliers of this type of equipment are

Interstate equipment; http://www.go-iec.com/ and

Dopplemayr: Http://www.dopplemayr.com

There are many systems still in use in specific applications. ■

If steep inclines and disorderly terrain is the problem, I believe the pipe conveyor system is a fairly well established solution. The only catch is that such a system would have to carry only crushed bulk - which, I suppose would be the case for an aerieal ropeway too - to be economically viable.

Kayem ■

FYI....Falconbridge are planning on Nickel refinery in New Caledonia - the mine is in the mountains and the plant is at the port. There plan to transport the bulk material up hill and down dale and around a few bends with a single belt conveyor...I have seen the topographic view - it will be a challenge.

I beleive that Conveyor Dynamics and Gary James ex Bechtel fellow are involved with the design.

Cheers

James Morrish ■

Please check the Pnuetrans web site for very good information on coveying materials of this type.

www.pnuetrans.net ■

Clearly, you require a study that develops the capital costs and the recurring costs for both systems.

Some years ago the writer performed such a study with the following approximate parametrs:

Initial System:

An existing twin aerial rope way system, transporting 318 t/h (350 STPH) of coal refuse (rock, silt clay) from the prep plant to a refuse pond.

Terrain: Virginia, USA Mountain side

Length: 454 meters (1490 ft)

Lift: 175 meters (575')

This is clearly a high angle conveying requirement.

Required new System:

Same profile requirements but increased conveying rate to 454 t/h (500 STPH)

Options Considered:

1.) Add a third aerial ropway, rated 136 t/h (150 STPH)

2.) Replace the total transport requirements 454 t/h (500 STPH) with a Dos Santos Sandwich Belt high-angle conveyor.

The best solution in that case was overwhelmingly the sandwich belt high-angle conveyor. That system went into operation in the early 1990's.

We would be happy to perform such a study for you.

Joseph A. Dos Santos, PE ■