The only cars that I know of that separate for bottom dumping are used for tunneling work behind tunnel boring machines and your desired rate of haulage and dumping would never be met with these cars and underground mine locomotives even though they dump at a slow speed without stopping and will need special rail and "rack rail" equipment

The only other option is to use a lot of ore jennies-short iron ore cars used in the iron ore strip mine itself they will work as they have bottom dump doors-but they will not continously dump on the move.

The only rail cars that will dump on the move are railbed ballast stone cars-with side dump chutes but you will need the carhoe any way as the ore will be frozen in the cars.

You will only achieve that rate of dumping with a rotary car dumper or as it is commonly referrred to as a wagon tippler.

It will be much simpler for you to invest in a "Carhoe" to empty out bottom door hopper cars with a shallow plow conveyor under the rail siding to carry away the ore.

The plow conveyor will do all your work for you as it can be set up with a continous horizontal loop/racetrack, hence you have no need of a belt conveyor, recieving hopper or an extremely deep excavation.

Check them out here:

www.carhoe.com

They are simple machine to own and operate and work in all weather conditions world wide. ■

If U go for the conventional hopper/feeder and conveyor > U are up for a deep excavation and costs.

In the coal ports in Qld, I believe unloading rates are up to 4000tph.

We do 2000tph.

U need to

get lenght of wagon and tonnage and also wagon spacing

find out dump time - will be typ less than 20 sec.

train speed will be function of unloading rate and time

hopper lenght needs to suit wagon dump time vs speed plus extra for : door issues, characteistics of hopper discharge device ie even draw down or not...plus some more.

ensure that the train speed controller is good and steady.

hopper capaicty needs to be at least 2 x wagon capacity

then U need to look at feeders > rate > determine lenght/width > then look at hopper wall / valley angles and opening size at rail level > work out dimensions acc.

Thanks

James ■

EDI Rail in Aust sell the QUIK-DROP rail car bottom dump door opening triggers. These are air driven ramps that pop-up and act on levers on the rail cars.

The system used to be called ABB QUIK-DROP. It is used on all of QR fleet (about 5000 coal wagon fleet) and all Hunter Valley coal fleet (similar size).

Unloading rates are up to 6,000 MT/h. Hopper lengths of up to 40m. The 6,000 tph unloaders at Newcastle run belt feeders onto belt conveyors. No other feeders. Deep excavation required. ■

Dear Mr. Gruia Grigore,

There are two widely used methods for unloading of rail cars.

- The one method is to use wagon tippler with associated system. This system is extensively used in India. This type of arrangement is preferred when the coal is coming from long distance and Railways often prefer conventional wagons for such transport.

- The other method is to use bottom discharge wagons. This type of system is also being used in India, when power plant is located near coal mine and the railway system is specifically serving such complex. The distance between mine and power station could be up to 100 kms.

In the second method, there is a track hopper of medium length. This track hopper should have volume to accommodate coal being emptied for at least one rake of wagons. In reality its capacity would be at least 1.5 times or more than the rake capacity. In this system the wagons have bottom discharge which are actuated by magnetic mechanism (line side rail). The rake moves at a slow speed and passes over the track hopper. Each wagon passage from beginning to end results into emptying of material into the track hopper. The material so unloaded is conveyed by paddle feeder etc. This is the high capacity system, serving the power station round the clock. If you happen to visit India you can see such system.

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 ■

Very interesting.

Can anybody give me some information regarding railway structure for bottom discharge? Is it steel or concrete structure? Is there any sleeper below the rail? Is bottom dump discharge door open automaticaly or manually?

Because in here, Indonesia, does not have unloading system like that. Presently Indonesia uses rotary car dumper for discharge the coal. A new investor wants to use bottom car discharge.

Thanks.

Irwan Joe ■

Greetings,

Using a bottom dump sysytem to replace a rotary car dumper is counter productive unless the rotary dumper is damaged beyond repair or their is a willing buyer for it sight unseen.

A bottom dump system usually manifests itself two ways:

An elevated trestle is used to drop the coal through the trestle and it is removed from under the trestle- this requires the least amount of work for preparation as a concrete trestle with track panels is a fast installation after the proper foundations are set in place for the weight of the coal cars and locomotiives.

A ground unloading system where there is an undercar plow conveyor with a "carhoe" to push the coal through the bottom of the hopper bottom doors.

Google (railcar unloaders)

Also

<www.carhoe.com> ■

Originally Posted by ggrigore

Hello,

I'm looking for a system to unloading railcars in motion at 3,500 mt/hr. The material is iron ore of 140#/cu.ft.

In my opinion, the complete system has to include the following items:

- long hopper in order to empty each wagon (but how long??)

- rotary plow feeders under the hopper

- a belt conveyor under the plow feeders

- a side system that will open automatically the bottom gates of the cars.

Any ideas or manufacturer references will be appreciated.

Thanks,

Gruia Grigore, eng.

(450) 464-4426

ggrigore@sotecma.com

Dear Mr. Grigore,

Your desired tonnage is the problem as the

only available "true to type"

bottom dumping rail cars are

used for tunnel muck train service in the

narrow guage rail size and have a low tonnage per car.

Is there a specific reason besides expense,

high water table, or limited space versus

of a rotary dumper that prevents you or limits

your options?

The other options that allows you any flexibility

is the use of "Ore Jennies" which are smaller side dump

iron ore cars which are used in the United States

Great Lakes Basin iron ore railroads which delivers the

iron ore to the iron ore ship loading docks on Lake Superior.

Option two are the side dump air operated railroad ballast cars

which are either equipped with manual or radio controlled air

operated side dumping gates.

The combining of a plow feeder and belt conveyor is counterproductive

when the use of long 24 inch wide apron feeder under a car load capacity

hopper and using a 24 inch belt conveyor after the apron feeder would be

more than adequate for this.

You need to be more concerned about sizing and using a www.Carhoe.com

to assure the flow of material the year round as the material will not go willingly. ■

Bottom dump railcars are the automatic choice in European bulk handling operations. What stopped the bottom falling out of the railcar market?

Surely tippling the waggons is slower. Further; can somebody explain why the excavation work is less with a tippler? A hopper of a certain capacity is the same whatever the input method at the top; valley angles will be the same; friction will be the same so all in all the hoppers will be the same and need the same civil preparation etc....All due respect to H & P (PO Box 15 Pittsburg is no mean acheivement) but surely the days of tippling are coming to an end....except apparently in India.

Regarding the ground hopper length, it is a red herring. The competent designer will provide a take out system which restricts the hopper length so that discharge is concentrated at one place. Otherwise the cargo is being dropped hither and thither and all semblance of order will disappear in clouds of toxic grit.

Look at some of the modern unloading systems from eg. Aumund Group and see the proper ways to unload vehicles. ■

Hi, Think something innovative.Let me put my innovative thinking in front of Hon. members .

1.About the design of bottom hopper--For better turn around time for the wagons it is recommended to go for twin hopper where you can unload two wagon at a time.

2.Plough feeder-This equipment increases to depth of the pit.The depth of the pit in this case may go as deep as 18-20 m below the ground which calls for huge investment in civil work and also chances of flooding.Now,instead of plow feeder an innovative system is there in the market designed by Picor,USA, where you can reclaim the material through vibrations by hydraulic driven motors.In this case depth will reduced down by 5-6 m.

We have designed lot of systems like this in India.Recently Halcrow has appointed us a their sub consultant for doing system designed check for 10 mtpa iron ore terminal at Paradip Port,India.

Invest some time and money,you will get a suitable system.We are very sure that we can reduce the Capex by 25-30% and also the operating charges by 20%.

We are ready to take this challenge. Good Luck dear.

Anil Seth

Director

Libran Engineering&Services

www.libranengineering&Services

Material Handling Advisor/Technical support to world's renowned cos.in the field of Port and Logistic sectors--

1.Royal Haskoning

2.Halcrow

3.Aecom

4.Mounsel/Fredrick-R-Harris

5.KPMG

6.DREWRY

7.DELOITTE

8.THE TATA STEEL(TMILL) ■

Does the bottom dump cost per car weigh heavily on the overall ore care cost vs. rotating dump?

However, I can see a possible advantage in dump time even when two cars are dumped together with rotary dumper.

We are DEM dump car modeling/simulating, with our ROCKY code, a complete dump hopper with bottom dump cars. Seems like the hopper designs do not consider the ore slug dynamics, and use brute force to overcome these dynamics. There are means to reduce the high impact and slug flow that now requires special belts and motor sizing. Belts wear out in very short order. We expect to increase belt life by a factor of 3-5 times or more. ROCKY can quantify the belt impact (puncture) and shear (wear) actions in any hopper system and belt recovery design.

See our website for an introduction to ROCKY. www.conveyor-dynamics.com ■