PROPOSED PROPOSED BHJ/BHQ BENEFICIATION PLANT BHJ/BHQ BENEFICIATION PLANT AT DONIMALAI- AT A GlANCEAT DONIMALAI- AT A GlANCE

The per capita consumption of steel in a country

is considered as the barometer for assessment

of development of that country.

The per capita consumption of steel in India is about 47 kg compared with 190 kg in the

world and about 400 kg in developed nations.

NMDC has started production of iron ore from the Donimalai Iron Ore Project in the year 1977.

• Donimalai mine has vast reserves of BHJ/BHQ of 41.45% Fe grade, (18 million tons approximately) Hitherto considered as waste and dumped in a valley.• An instruction has been received from the IBM to preserve the Iron ore containing more than 40% FE for future use.

NMDC has been striving for value addition to Iron ore largely through the following routes.

Beneficiation : Lean grade Iron ores including BHJ/BHQ Slime/Low grade Fines/Tailings Upgradation

Agglomeration including sintering and Peletization. With a view to add value to the BHJ/BHQ hitherto mined as waste and also for mineral conservation.

NMDC has started to set up a Beneficiation plant for processing this low grade material to obtain BF grade concentrate suitable for peletization.

The beneficiation tests have been carried out in

our R & D Centre and tentative optimum process

flow sheet and metallurgical balance flow sheet

have been prepared by NMDC and requested

M/S MECON to review the process flow

sheets, optimize the schemes, workout

cost estimates, techno-economics and furnish

a bankable Techno-Economic Feasibility

Report (TEFR) for Beneficiation of

0.36 MTPA BHJ/BHQ Beneficiation plant at

an investment of Rs150 Crore.

Chemical Composition of Donimalai Sample

2W 2E 3E 3W

Fe 33.86 41.10 39.49 40.23

SiO2 50.70 38.01 41.54 41.48

Al2O3 0.32 2.13 1.28 0.42

LOI 0.12 0.66 0.27 0.13

P 0.039 0.018 0.018 0.023

• The mine is operating with a capacity of 7 million tons per annum.• An instruction has been given by the IBM to all miners to preserve the ore contains more than 40% FE for future use.• Donimalai mine has vast reserves of BHJ/BHQ of 41.45% Fe grade, Hitherto considered as waste and dumped in a valley.

Beneficiation Studies

Beneficiation studies using various techniques such as hydrocyclone, spiral, magnetic separation, flotation etc that are to be carried out.The separation technique selection is based on the particle size and properties. Main purpose is up gradation of iron ore values and to reduce the gangue content.

Up gradation strategy: Based on the characterization studies the following batch tests were attempted to understand the response of different beneficiation techniques. Tests were conducted with the sample ground to 0.150 mm top size: Gravity Separation – Floatex Density Separator Magnetic Separation – WHIMS(wet high intensity magnetic seperator)

Process Description :

Design Considerations

The Crushing and Beneficiation Plant is

designed to process BHJ/BHQ iron ore

of -200 mm size to produce concentrate

iron ore grade (65.08% Fe) of size -150 microns.

It has been considered that the crushing

plant will be operating at 100TPH for

3600 working hours in a year and

beneficiation plant will be operating at

60TPH for 6000 working hours in a year.In order to produce 0.118 MTPA of concentrate,

the feed requirement for the Crushing &

Beneficiation Plant will be 0.36 MTPA considering 32.9%

recovery by weight.

· The Crushing and Screening plant shall have the following equipments:

· Dumper Platform· Dump Hopper· Vibro-Feeder cum Grizzly· Jaw Crusher (32” x 20” size)· Double Deck Vibrating Screen Cone Crusher· Storage Bin· Belt Conveyors· EOT Cranes

The BHJ/BHQ of -200mm size material is fed on to a vibro feeder cum grizzly.

The over size (+50mm) material from the grizzly is fed to primary crusher for crushing and the undersize material is screened using a double deck screen. The oversize material from the double deck screen is crushed in a secondary cone crusher for further size reduction.

• The crushed material from cone crusher is screened again and the over size is re circulated back to cone crusher.

• The screen undersize (8mm,80%passing) is transferred to a storage bin. The crushed fines stored in the bin are fed to a ball mill for wet-grinding.

• BENEFICIATION :• The ball mill discharge is subjected to classification using hydro-cyclones of separation size of 150 microns (106 microns, 80% passing).

• The underflow is again fed back to ball mill for re-grinding. The ball mill overflow is subjected to de-sliming using hydro-cyclones to separate the slimes at 25 microns.

• The underflow of de-sliming cyclones is further processed using gravity spiral concentrators and the concentrate is stored in a concentrate storage tank.

• The overflow from the de-sliming cyclones and the tails from the spirals are fed to tailing thickener for recovery of water.

The thickened tails are pumped to tailing dam.The concentrate from the storage tank is pumped to pressure filter for removal of water and the product is stored in product storage yard to transport to pellet plant.

Technological Facilities:

The Crushing and Beneficiation Plant shall

have a rated capacity of 100 TPH and 60 TPH respectively.

Beneficiation Plant :

· Ball Mill· Cyclone· Spirals· Thickening· Filtration· Product/Concentrate Stock pile· Tailing disposal to tailing dam.· Water reclamation and distribution.

Service Facilities :

Process WaterThe source of water for the project is from water treatment plant at Donimalai base camp located about 6km from the plant site. Water from thiswater treatment plant is pumped to a storage tank of capacity 1,200 cubic meter located adjacent to the plant site. Water from this tank is made available to the main water pump house by gravity. A recirculation water tank and a pump house are planned for necessary pumping and distributionto different consumers in the plant.

PowerThe estimated power requirement for the proposed Crushing, Screening andBeneficiation plant is as follows:-Maximum Demand : 1.6 MVA(1600 KVA)Annual Energy Consumption : 11 M W

ManpowerThe estimated manpower requirement for operation and maintenance of Crushing, Screening and Beneficiation Plant is 52, including Executives andNon-Executives other than contract labours.

FOREST BORDER PILLERS NEAR PROPOSED PLANT.

The progress of BHJ beneficiation plant : Plate load tests of BHJ plant area has completed by M/S Geo tech Ltd, Hyderabad. M/s Dorr o liver will start the plant erection works shortly. Consultancy and construction work contract of Dam at 2E/3E valley for dumping of tailings of 6.2 Million tons has been awarded to M/S Wapcos limited. Proposed Dam area Soil testing completed. Trees remuneration work is under progress.