How many more problems do you want!!!!!!!!!!!

You could change the gear box and increase the speed but:

1. It will require a new gear box and electric motor and spares for both if they are intent on this assuming you can not use the same motor frame size and horsepower.

2. More chance of belt damage-are there any training idlers on the top or bottom of the belt?

(a) what type of belt splice are you using.

(b) more stress on the splices, more chances of belt ripping or damge.

(c) reduced carcass life of the stacker belt-unless your really cheap and reuse all your belts to the point that they fall apart.

Reduction in bearing life is a big thing to condsider as there is only so much B-10 life to go around.

3 What is used for belt tension?

I guess you could lick your wounds now or do it later after it screws up.

Typically a 36 inch belt will handle 450 tons per hour minus six inch ores.

Count you blessings and go to the CEMA web Site if you are really intent on this.

The co op students that worked in the hole I worked in during the summer were always sent on hunting expeditions-meaning every co op student usually got sent to the hinterlands to inventory and verify all the conveyor belt drive motors and gear boxes every year they had an intern- busy work for work credit since they did not have a lot for them to do I guess.

Its a sad state of affairs when you see the chief engineer using a spanner for a plumb bob OYYY!

After that incident his nick name became

"plumb Bob"

It was not my idea, I just heard about it :^)

The guy runs engineering for three mines now go figure. ■

Dear Steve,

You can go faster than 500 fpm. There are a number of conditions and caveats, but many long overlands in your size range operate over 1000 fpm.

Assuming the gypsum will not generate unacceptable dust due to air erosion, the key point is the loading and chute configuration. Most older chutes are not designed to soft load the belt. Often the material is placed on the belt in a vertical stream. Not good.

The quality of your components is important. Bad idler concentricity, eccentricity, et al may limit the speed.

THe receiving chute may not be able to take the flow physics.

Due to its short length, I would guess the pulley diameter tolerances canl be limiting.

Belt construction, idler construction, ...... all must be reveiwed,

There are many added conditions which must be met to go fast and not have the components fail. ■

Steve

Is the stacker in question the one installed by FMC around 1978? If so, I remember detailing some of the steel for it.

The problem might not be so much in the belt, but in pushing more material down the chute onto the belt. If it is the stacker I am thinking about it has a round chute into the stacker belt skirts which may limit your capacity. When the stacker is slewed to one side you will need to be sure you are loading on centre or tracking problems will result. ■

Again with tears in my eyes...Why is there a bottleneck...is there a bottleneck? In a conveying line all the items should be capable of handling the design throughput. Somebody has specified tackle, checked bids, witnessed commissioning, signed for acceptance ...and now somebody tells you there are bottlenecks. It's not the stacker boom that needs looking at is it? ■

Dear Mr. Steve,

You have 30” belt handling gypsum of 3” lump size. Your belt conveyor is currently running at 483 fpm. It seems you intend to increase the speed somewhere around 500 fpm. You can increase the speed to 500 fpm or more, because the material you have mentioned is not a problematic material.

There is no hard and fast dividing line for the belt speed adopted. While making the change in belt speed, it is advisable to recheck the conveyor from design point of view and incorporate the corrective measures accordingly. If there is remarkable change, then existing components quality should be also compatible to the new situation.

Regards,

Ishwar G Mulani.

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

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

If you had told us in the beginning there was a complete conveyor upgrade in the pre screening and before the tertiary circuits if any when you posted your message it would have made more sense, are you making wall board at this mine or simply shipping ores it to a secondary facility where it is crushed, blended, and made into wall board in a mixing plant?

You did not even begin to discuss the load out system at your facility if any and if it can not absorb additional tonnage the thread was indeed pointless. Apron feeders can only move so much rock in relation to their chute size or the size of a drawpoint in a stock pile.

The other big item you never discussed is: can your stockpile size absorb an increase in throughput? Remember there is only so much room anywhere you dump it as the draw point is the big factor.

You might as well solve your problem now and tell them the simple thing to do is run the belt a little longer 24 hours versus 16 etc., and solve your problem that way as it is the simplest least costly solution. you have not even told us if you have a surge pile feeding the stacker so answers are really out of the question.

You have not given us a flow diagram or schematic of your ore processing plant so our help is pointless as we do not now the layout of your procesing unit.

Hind sight is 20-20 and they obviously did not consider changing out the stacker first as the last link/the stacker and loadout is the weakest point in your system as they did not do their home work. Did they even state whether they are increasing loadout speed/tonnage? The exercise is really pointless if not as tons per hour at the load out is all based on the total puzzle.

You can get spillage at any belt speed if a troughing idler breaks and the belt starts to tear or the load will fall to one side and dump off.

Been there done that.

Rubber impact beds are a good choice if your belt frame has the room for the mounting frames.

Spliting the flow with a divider to spread the discharge is more trouble than its worth with the potential for plug ups. ■

I think everyone has agreed that speeding up the belt can be done. Also everyone agrees that every component that will be subject to higher horsepower and loads needs to be checked for strength and durability. The area that will need the biggest redesign, though, is the loading and, possibly, the discharging of the belt. With a simple vertical loading of the belt, material gets thrown every which way and the surface of the belt gets worn very quickly as the belt has to accelerate the material in the new direction of travel. A well designed chute is needed to convert the vertical speed of the falling material into a horizontal component - ideally matching the belt speed. By doing so, the belt cover wear will be minimized and scattering of your material will be minimized as well. The trick is to do it without plugging the chute. I'd suggest going to either Air Control Science in Boulder, Colorado or to Martin Engineering for computer designed chutes to accomplish this. ■

Dear Steve,

We have a chute design that will soft-load and increase product speed in the direction of the receiving belt no matter is orientation horizontally of vertically and horizontally.

Drop us an emaiil (below) if interested. ■