Mechanical Operations

411. Which of the following is the most suitable for cleaning of fine coal dust (<0.5 mm)?

1. Trough washer
2. Baum jig washer
3. Spiral separator
4. Froth floatation

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412. Which of the following is the most suitable for handling fibrous and dense slurries?

1. Propeller agitator
2. Cone type agitator
3. Turbine agitator
4. Radial propeller agitator

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413. Which of the following is the softest material?

1. Talc
2. Feldspar
3. Corundum
4. Calcite

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414. Which of the following is used for primary crushing of very hard lumpy materials?

1. Toothed roll crusher
2. Gyratory crusher
3. Ball mill
4. Tube mill

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415. Which of the following may prove unsuitable for filtering volatile liquids?

1. Pressure filter
2. Gravity filter
3. Centrifugal filter
4. Vacuum filter

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416. Which of the following mechanical conveyors does not come under the division „carriers‟?

1. Belt conveyor
2. Bucket elevator
3. Screw conveyor
4. Apron conveyor

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417. Which of the following mechanical conveyors does not come under the division „scrapers‟?

1. Ribbon conveyor
2. Flight conveyor
3. Bucket elevators
4. Drag conveyor

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418. Which of the following mineral dressing operations is termed as 'comminution'?

1. Panning
2. Spiralling
3. Tabling
4. None of these

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419. Which of the following minerals is not subjected to magnetic separation method?

1. Rutile
2. Galena
3. Chromite
4. Siderite

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420. Which of the following must be stored in silos and not in open yard?

1. Coke breeze
2. High V.M. bituminous coal
3. Sand
4. None of these

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