Dear Sushanta,

I am familiar with the system.

To remove the cable safely, two possibilities come to mind. These are roughly detailed below.

Method One:

[1] Remove the gondalas that are attached to the wire rope. This can be done at either end -- whichever is most convenient.

[2] At the plant end of the system, clamp and cut the wire rope. Attach one end to a winch (so you can reel the cable in stages). Attach a fabric rope to the trailing end of the cable and let it be fed onto the system as you remove the cable. You will end up with a fabric rope instead of the heavy cable. The reason for doing this is to prevent the heavy cable end from dragging through the water, being lifted at the next tower, and dropping to the water or ground again, and so on.

[3] Once the lighter fabric rope is on the system, attach one end to a winder, lower the rope from its elevated position (one tower at a time) and wind up the rope. It will be necessary to block off the water access, so boats do not become fouled in the rope.

[4] Continue reeling in the rope until the system is empty.

Method Two:

[1] Lower the wire rope from each tower until all of the rope is laying on a floating base, comprised of plontoons.

[2] Clamp, cut, and wind the lowered cable. Note that you should only lower the cable from one tower at a time and wind up the slack before proceeding to the next tower. Also, you can use floatation devices attached to the cable to keep it on, or near, the surface.

[3] As with the other method, it will be necessary to control access to the area to prevent fouling.

If retention of the cable is not important, you can clamp the cable at each tower. Then you can cut and lower it in sections that will be easier to handle -- place a winch on a barge to wind up each cable section as it is lowered, moving the barge from one tower to the next as it is winding.

As always, whenever a problem presents itself there are multiple solutions. Those offered above are given as possibilities only, without study of the system (i.e. I've only driven by it while your belt conveyors were being installed). You may want to contact the original installation company for their input -- they had the same problem in reverse.

Regards, ■

You already have a good answer.

However, my suggestion is that you should also obtain advice from the supplier of this rope way for specific procedure to be followed for this kind of maintenance / replacement. You can also look for the maintenance manual provided by the original supplier of the equipment.

This activity can result into a serious mishap / damage if done without proper / specific procedure. The job demands sequential work procedure / steps to be followed in a very methodical manner with full knowledge of the forces that develop in the system during this activity and their remedial measures.

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 ■