Morning John..

Don't worry about the dynamics of starting and stopping, as long as you put the gravity take-up at the tail.

We have several such installations here in South Africa, and even our long man-riding conveyor stringers are suspended from the hanging wall.

No sign of flapping in the breeze.

Glad you are sourcing from South Africa.

Regards

LSL Tekpro ■

The loadings are about the same as for a ground structure + maybe some idler pendulum effects. You should X brace longitudinally, using wire rope in tension. Use the same pitch for the braced spans that you would use for a comparable ground structure.

Your only serious lateral forces would be seismic; so depending on how near the blasting you run will determine how much lateral tensile bracing you might need.

What does the exporter recommend? ■

Dear John RZ

Your point 4 is not correct. The support ropes or cables, or chains will hang vertically. To make them hang normal to the belt axis the idler frame must be pulled forward. Where is this reaction taken out? This is unnatural. A tension member must restrain motion from the ceiling to hold the vertical supports normal to the belt.

There can be detrimental vibratory effects that fatigue and fail the vertical supports. Specifically, the eyelets, which are fastened to the stringer, fail at the thread due to the pumping into and out of tension. ■

Dear Mr. John,

The earlier respondents have already given certain replies.

Firstly, the suspension arrangement is not very clear to me, but it seems that idler have suspension mounting from ceiling. The rule is that the idler plane (i.e. the plane formed by the middle roller and two side rollers) should be perpendicular to the belt motion. If this is not perpendicular then there will be more wear of the belt and also the roller periphery. This point has been already mentioned by Mr. Nordell.

The suspension system should provide lateral as well as longitudinal stability to the conveyor i.e. suspension should not act like a swing. One can prevent this by appropriate means in varied manner, if he has opted for that. As for the suspension view across the conveyor, the suspension distance at roof should be sufficiently large compared to the suspension distance at lower level. This will tend to reduce the lateral swing. In such swing, the bottom portion will not remain parallel to the suspension point of roof (i.e. because it is not forming parallelogram as opposite sides would not be equal and also two sides in vertical plane are not rigid) It is not possible to give specific comment without fully visualizing the actual arrangement; however possibly, I will give one or two more comments as a general rule about four side polygon behaviour.

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 ■

Vertical is straight up from the horizontal earth plane like making the vertical supports in your house set by a level bubble while the level tool is vertical and aligned with the stud.

Perpendicular to the belt axis means normal or at a right angle to the plane of the belt while at a 17 degree slope.

If the belt is inclined 17 degrees, then the vertical chain support has an included angle of 17 degrees with the plane perpendicular to the belt. ■

regardiing your inquiry,

you have not told a whole lot as we need more information.

Is the decline intake or exhaust air?

Typically belts installed on a decline are either hung from the roof with a cable supported belt with ring chain hangers or installed on the floor with either a cable supported belt or a steel supported belt with a a driven head pulley unit anchored to the floor at the top of the decline or a passive head pulley anchored to the roof line driven by a middle drive unit at the bottom of the decline as it will be properly anchored to the floor-if the floor is good and unbroken.

Potential problems:

1. splice failure and belt roll back all the way to the bottom gaining speed.-it happens with vulcanised splices too.

2. idlers set to high in roof line - poor maintenance/lack of greasing, harder to change idlers, inability to inspect belt line, dlers at every tenth troughing idler and at at every tenth return idler you will have problems.

3. what about your convergence pins?, how will you read them if the are in the belt line proper? will new pins/ provide you with accurate information due to the age of the tunnel and its past convergence?, what is the annual convergence?

4. have you installed/ bolted fencing/mesh in the roof to allow for safe passage in the decline? do you have the height to allow for roof bolting and installing mesh in the roof?

5 what about the roof? how often is it inspected or scaled-trimmed?

6. which roof bolt do you normally use? mechanical, resin or swellex? this a huge consideration as it will effect you hangers and the design load. if you use resin bolts you can forget about recovery of the chain hangers when the time comes.

over here we use 2 foot mechanicals to hold the chain hangers on conveyor belt.

7. with roof convergence in mind you will have to realign the belt periodically to keep it level from side to side and trained properly.

8. access to the other side of the belt needs to be considered as well as it relates to belt maintenance and repairs.

The nice thing about capsule pipeline is that is is very low maintenance and you would be able to reuse the railroad ties to secure the capsule pipeline if they are in good condition.

Another excellent benefit is that the air volume moved by the capsule pipeline during operation wil help to ventilate the mine proper by huge amounts reducing smoke from shooting and diesel exhaust gasses.

The capsule pipeline will also allow you to use synchronus motors and you will be able to generate electricity when it is operated/pushed in reverse/where the blower is running backwards due to the force of the air pushing the capsule trains down the decline.

If power is lost the capsule train will slow to a stop as a column of air is slowing it down to zero/fullstop it will run normally when power is restored without interupption.

To see a capsule pipeline in operation that replaced a railline go to <www.capsu.org> the system in use replaced a railroad line from a quarry to a cement plant.

Also <www.pnuetrans.net>

the big plus about capsule pipelines is no shoveling, no belt spills,

no conveyor belt fires and a reduced need for labor. ■