Home/Volume-1/Bord and Piller Method – 2 Volume-1 Bord and Piller Method – 2 Admin02/08/20240 59 Less than a minute Report a question What's wrong with this question? You cannot submit an empty report. Please add some details. 0% Bord and Piller Method of Working Coal Bord and Piller Method - 2 1 / 28 1. For designing pillars.....is used? coward's diagram proximate analysis nomographs none of the above 2 / 28 2. In shallow seams to prevent breathing of air to the depillared area through cracks to the surface the cracks have to be blanketed with a minimum thickness of layer of sand or earth nearly? 1m 1.2m 1.5m 2m 3 / 28 3. In deciding the size of the panel the important factor to be considered is? thickness of the seam output required depth of the seam incubation period 4 / 28 4. The method suitable for working seam under the workings of another seam which is water logged or on fire is? Longwall retreat Bord and pillar Hydraulic mining Longwall advancing 5 / 28 5. The limiting depth for the bord and pillar mining is? 200 m 300 m 400 m 500 m 6 / 28 6. For given perimeter the greatest area of support is offered by ? square rectangle rhombus circular 7 / 28 7. The first indication of roof weighting for regular fracturing roof in goaf is? Prop when tapped with stick produce dull and dummy sound lid over the prop bends rumbling sound in goaf penetration of prop into floor 8 / 28 8. Headings advancing in a direction at right angles to the main cleat are called? bords end places walls splits 9 / 28 9. The method suitable for workings seam under the surface containing valuable property water bodies for whose protection some coal is left unworked is? Longwall retreat Bord and pillar Hydraulic mining Longwall advancing 10 / 28 10. The shape of the pillar in steep seams for haulage and loading and in flat and inclined seam for adoption of high capacity machinery like shuttle cars and locomotive is ? square rectangle rhombus circular 11 / 28 11. Overriding of pillars and stooks and premature collapse in the depillaring area is due to presence of? Strong thick massive sandstone strong coal Weak strata Water bearing strata 12 / 28 12. Heavy roof fall and even premature collapse may taken place if line of goaf is? parallel to strike diagonal right angle to fault parallel to fault 13 / 28 13. The percentage of extraction of coal from a pillar of 30m x 30 m center to center with roadways 4m wide is ? 30 28 22 25 14 / 28 14. Maximum roof exposure for caving is? 30 to 50 sq.m 60 to 90 sq.m 90 to 100 sq.m 100 to 120 sq.m 15 / 28 15. The groove made by coal cutting machine is called as ? web cuthole channel none 16 / 28 16. Maximum roof exposure for stowing is? 30 to 50 sq.m 60 to 90 sq.m 90 to 100 sq.m 100 to 120 sq.m 17 / 28 17. In a seam with locomotive haulage system the junctions with main headings are staggered ? For easy travelling of loco to minimize roof exposure to reduce ventilation air loss none of the above 18 / 28 18. The sudden release of elastic strain energy stored in the pillars results violent burst of coal pillars is called? Air blast Bumps Rock burst Main fall 19 / 28 19. With strong roof and unyielding floor tends to? Crush the roof Heave the floor Crush the sides of pillars Spontaneous heating 20 / 28 20. The width of the headings in bord and pillar method of working depends on? depth of working size of the pillars face machinery used ventilation required 21 / 28 21. Shuttle cars are the transporting media for ? Longwall Bord and pillar Open cast Hydraulic mining 22 / 28 22. While working seams steeper than 1 in 4 except the haulage dip the cross connections between the levels should be? on mild gradient provided with steps straight aligned staggered 23 / 28 23. The maximum compressive strength of cavable roof? 300 kg/sq.cm 400 kg/sq.cm 500 kg/sq.cm 600 kg/sq.cm 24 / 28 24. The daily advance in development of galleries by continuous miner? 20m 30m 40m 50m 25 / 28 25. The number of panels to be opened at a time is decided by ? Capacity of the direct rope haulage Output desired Thickness of the seam Incubation period 26 / 28 26. Heading advancing parallel to cleats are called? bord wall slice none 27 / 28 27. The shape of the pillar that gives maximum percentage of recovery with speed reduced amount of lift for loading is? square rectangle rhombus circular 28 / 28 28. The minimum factor of safety in design pillar in bord and pillar mining? 1 2 3 4 Your score is The average score is 56% LinkedIn Facebook Twitter 0% Admin02/08/20240 59 Less than a minute
