Dear Mr.Banerjee,

In order to avoid/minimize demmorrage charges,the requirement of the rake loading operation is to design a reliable flow over-head bunker system (say 2,900 T capacity,assuming 50T per wagon for a 58 wagon rake;capacity to be decided based on the actual wagon capacity) with mass flow/expanded flow configuration,above the 50T hopper system operating with hydraulic gates to deliver the required quantity of the ore to each wagon.

Kindly let me know the size analysis of the ore,expected moisture content especially during the Indian mansoon season,time required to load one complete rake(58 wagons) and number of rakes to be leoaded on a 24 hr.basis.

Based on the above information, we may have to carryout Shear Tests to establish the flow characteristics typical to the ore under consideration and then design a reliable flow bunker system for trouble-free rake loading operations.

Dr.V.LakshmanRao

President,

Institute of Particulate Technology-International(IPTI)

Hyderabad

India ■

Dear Mr.Banerjee,

Many thanks for furnishing the information. This, am afraid leads me to seek more clarifications because our focus is the Bunker system that holds the saleable iron ore (minus 10 mm +65Mesh) with storage and live capacities being the same (say 2,900T); and this is possible with a mass flow system configuration. Logically the upstream facilities (eg. Belt conveyor systems) in the handling plant layout are to be addressed subsequently for a proper and good performing system design.

2.What is the space allocation (including the Head Room) provided in the plant layout for the bunker system?

3.How many Rakes are to be loaded on a 24 Hr. basis? This allows us to determine the Storage time tests that further would help in devising an Expanded Flow Bunker configuration to save in the Head Room.

4.Usually the minus 2mm size fraction in the iron ore contributes to the cohesive strength of the total ore mass at different wetness levels (7-8%usually cause worst flowability conditions for iron ore fines) held in the bunker. I presume this size fraction will be close to 50% by weight in the iron ore bulk under consideration (Kindly clarify). Consequently it is important to establish the relationship between yield strength and consolidation load (flow function curves); compressibility tests (bulk density vs. consolidation loads expected in the bunker system) at critical wetness level for the iron ore. In addition Kinematic angle of friction against select liner materials also needs to be established.

5.Is the proposed bunker will handle only the iron ore fines under consideration or ores from other sources are to be considered?

Warm regards

Dr.V.L.Rao ■

Hello,

Presently proposed; you need to place a 50tonne shot every minute for 10 hours a day.

Altenatively you can break the shots down to 2 x 25 tonnes and load the cars, single file, on the move. That way you could afford to incorporate a, now smaller, standby unit.

There is a lot of shunting to be gone through before you get to the desired loading level. The 10 hours supposedly necessary will spin out to 15 in practice, assuming the tare and laden car weights will be recorded/documented for the client.etc.. This extra time restricts the available maintenance period.

I will be publishing (hopefully next week) a development of a moving car bunker inversion which will release material under the direct action of the moving car passing beneath. It will be spillage free and requires no headroom clearance, which will reduce the otherwise very fierce dust generation. For an application such as yours I would incorporate a gravity counterweight return to provide rapid closure; all without external power (hydraulic, pneumatic or whatever) and fail safe, if you're interested. ■

DEAR BANERJEE,

PLEASE CONTACT/REFER YOUR QUERRIES TO MR. BILL MCHALE OF M/S KANAWHASCALES AND SYSTEMS AT E-MAIL--bmchale@aol.com and bmchale@kanawhascales.com

PLEASE NOTE THAT THIS COMPANY HAS INSTALLED MAXIMUM RAPID LOAD OUT STATIONS AND THEIR SHARE OF ENTIRE MARKET IS MORE THEN 75% .

REGARDS, ANIL SETH ■