Mine Management, Legislation & General Safety
1. Spontaneous heating in advanced stage has been selected in a caving district. How would you deal with the situation and what are the statutory obligations that should be fulfilled?
2. What could be the occupational health problems with increasing mechanisation? What steps should be taken to guard against the same.
3. Design emergency plan of a belowground mine with dangers from fire and inundation. How can you make it effective?
4. Write short notes on the following:
(a) Risk management
(b) Effectiveness of Safety Committee
(d) Training Officers
5. How can you make effective use of;
(a) Electronics and information technology in mine safety
(b) Site mixed slurry explosives with special reference to safety
6. Roof fall continues to be the single largest cause of fatal accidents in our coal mines. How would you reduce such accidents?
7. Under the present scenario comment on adequacy of safety status along with suggested improvements on;
(a) Duties and responsibilities of owner
(b) Statutory records and registers
(c) Duties and responsibilities of manager
(d) Workmen’s Inspector
8. A large blower has been encountered in a development district of a first degree gassy seam. How will you deal with it and what are the statutory obligations that need to be fulfilled.
Winning & Working
1. What are the advantages and limiting factors of application of dragline in opencast mines? Give a layout for a production of 4 million tonnes per annum from an opencast mine with dragline application. Thickness of coal seam is 20 m with a stripping ratio of 3 m3 of overburden per tonne of coal. Indicate the size of equipment and draw the balancing diagram. Assume other conditions.
2. What are the special problems and dangers associated with the following operations:
(a) Extraction of developed coal pillars by opencast method.
(b) Working a seam disturbed by extraction of an underlying seam.
(c) Blasting in the hot strata.
(d) Development of a seam at shallow depth.
Indicate precautions to be taken.
3. Write short notes on the following:
(a) Truck dispatch system in opencast mines
(b) Trackless mining
(c) Hydraulic profile in a slowing installation
(d) Hydraulic mining
4. An underground coal mine working a 3 in thick coal seam dipping at 1 in 10 is planned to produce 0.4 million tonnes per year with load haul dumper or side discharge loader for a production mix of 1:2 from depillaring and development respectively. Give standard layout of development and depillaring districts with equipment, manpower and productivity (OMS) details.
5. Write short notes on the following:
(a) Slope stability in quarries
(b) Local and main roof fall
(c) Angle of draw
(d) Overriding of pillars
6. A 15 metres thick seem lying at a depth of 200 metres has been developed along roof and also along the floor on board and pillar system. Describe the method of extracting the seam with sketches and indicate expected percentage of extraction. State assumed conditions.
7. Give a layout of an opencast mine having a capacity of 10 million tonnes of coal and 45 million cum of OB worked by shovel-dumper and dragline combinations. The coal seams are 20 m and 10 m thick with 25m parting dipping at 1 in 20 gradient and lying at a depth of 50m in to 160m. Indicate the number and capacity of major earth moving machines.
8. Write short notes on the following:
(a) Green roof support in conventional and mechanised development districts
(b) Blasting gallery method of extraction
(c) Common geological disturbances encountered in coal mining
(d) Pump pack
Mine Ventilation, Explosion, Fires & Inundation
1. Write short notes on any four of the following:
(i) Methane layering and layering number
(ii) Ventilation in sinking shaft
(iii) Stone dust barriers
(iv) Higher and lower explosive limits of methane, ethane, propane, carbon monoxide and hydrogen,
(v) Methane drainage
2. (a) Discuss the following:
(b) A LHD district has been sealed off in a mine due to fire. Explain in detail the procedure for monitoring the environmental condition of the sealed-off area and the procedure for reopening of the sealed-off area indicating clearly the organisation for the same and presenting the duties & responsibilities of persons dealing with the reopening operation.
3. (a) Discuss types of ventilation in long headings and statutory provisions in relation to ventilation in long headings during active drivage.
(b) The area of a evasee at the outlet is 12 m2, which is 3 times that of throat. Calculate the useful pressure recovery in evasee for a fan discharge of 200 m3 per second assuming 75% efficiency for the evasee. Calculate the following:
(i) the static pressure of the fan if the mine resistance is 0.04 NS2m3
(ii) the flow through the mine without the evasee, assuming the static pressure of the fan remains constant with or without evasee.
(iii) what is the hourly saving in the cost of power wasted as velocity head with the installation of the evasee if the combined fan and motor efficiency is taken constant at 60% and the cost of power as Rs 4.30 per kWh.
4. (a) What are the statutory provisions regarding precautions against dangers from underground inundation?
(b) Discuss in detail about the dangers associated with inundation while working in multi-sections. What are the specific dangers associated with working in an overlying seam when the stowed goaf of underlying seam is in the vicinity of active working ?
5. What are the statutory provisions regarding the inspection of subsidence area and the relevance of the same in prevention of fire (b) It is proposed to plan a highly mechanised mine with LHDs. Blasting gallery and Longwall with a targetted output of 2 million tonnes per year. Discuss in detail various aspects related to ventilation which needs consideration during extraction.
6. (a) Write short notes on the following-
(i) Ventilation survey
(ii) Ventilation in a continuous miner district.
(b) A typical highly mechanised powered support longwall district has been sealed off after collapse and subsequent fire. Explain in detail the statutory provisions to be fulfilled before reopening of sealed-off area and the procedure to be followed for reopening. (Assume your own conditions).
7. (a) Discuss the following.
(i) Need for evasee for the main mechanical ventilator
(ii) Operation of fans in series and parallel.
(b) A drift is ventilated by a ducting of a diameter 60 cms. What improvement in quantity would be made by replacing the dueling by one of 80 cms. diameter? What will be the difference in pressure required, if the same improvement is achieved by speeding up the fan? Which of the methods is cheaper?
8. (a) Write short notes on the following:
(i) N2 plant and its operation
(ii) Modem methods for monitoring the leakages from the seals
(b) An extensive area in a mine producing high grade coking coal is sealed-off due to fire. What precautions are to be taken to present further progress of fire? Discuss the equipment and organisation required for the same. Explain the procedure to be adopted to get the representative sample of atmosphere behind such an extensive sealed-off area. (Assume your own conditions).
1. A three phase transformer connected in delta-star is supplied with current at 3000 volts and gives current to a load at 600 volts. If this current is 400 amps at a power factor of 0.75 determine.
(a) The kW output
(b) The kVA input if the transformer has an efficiency of 96%
(c) The primary phase voltage and current and
(d) The secondary phase voltage and current,
2. (a) What is the purpose of recapping a winding rope ?
(b) At what interval has this to be done and what is the length of rope to be cut?
(c) What precautions are to be observed both during and after recappings?
3. In a turbine pump what is the highest suction head that you would arrange for ordinary cold water? A turbine pump has six impellers 30 cm dia running at 1440 rpm. The delivery branch is 15 cm bore and suction branch is 18 cm bore. For what rate of delivery of water and head should the pump be suitable? What should be the width of impeller outlet around its periphery, assuming a radial velocity of 2.4 m/sec. Assume manometric efficiency K – 0.6 and suction velocity 1.68m/sec.
4. Write short notes on the following:
(b) Rope shovel
(e) Surface miner
5. A locomotive and train have a total mass of 500 metric tones. If the locomotive can exert a constant pull of 120 kn Find how long it will take to accelerate the train from rest to 80 km/hour on a level track? The resistance opposing motion can be assumed as 60 N/tonne.
6. Discuss selection of equipment while planning a large mechanized opencast coal mine.
7. (a) What is the purpose of guides in a winding shaft ?
(b) Show with simple sketches the position of flexible and rigid guides in a shaft cross – section with respect to cages.
(c) Compare between flexible and rigid guides.
8. In the case of underground continuous mine district including 3 phase transformer, switchgear, cable and electric motor.
(a) What is the purpose of earthing.
(b) What parts of machine and apparatus would you earth and
(c) How the earthing is carried out ?
1. In a new coal block, a large sized mechanized opencast project is proposed to be opened. It has been decided to prepare plans and sections for proper measurement of overburden and coal. Describe the ground survey work required and the plans to be prepared.
2. The true dip of a coal seam is 1 in 5 due N 68°E. A heading PQ driven due S 52°E with a plan length of 200 m meets a down throw fault at Q. The fault has a vertical throw of 25 m and hade of 45° Assuming the fault to be at right angles to the true dip of the seam. Calculate the length of the shortest drift to be driven from P to exploit tile coal seam on the other side of the fault.
3. What is meant by the term triangulation? Why well-conditioned triangles are needed? The distance between two stations was measured by using a 20 m. Chain and was found to be 1500 m. The same distance was measured by using a 30 m chain and was found to be 1497.19 m. If the 20 m chain was 0.05 m too long, what was the error in 30m chain?
4. A coal seam 13 m. thick has been developed in two sections along roof and floor and vertically superimposed, the galleries being 3.6 m wide and 3 m high and pillar size 18 m center to center. For extraction of coal in second working, the colliery has been permitted to split the pillars into two equal parts. The split gallery and the original galleries are to be heightened to full thickness of the seam and all voids are to be stowed completely with sand.
Calculate-(i) the overall percentage of extraction of coal in the seam
(ii) ratio of coal raised in second working to that of sand stowed.
5. What are the statutory requirements to be observed by a surveyor while (a) approaching old unknown/water filled workings, (b) a mine is abandoned, (c) an old mine is reopened.(d) approaching common boundary of a mine, (e) working under railways and surface buildings and (f) it is proposed to start extraction of pillars?
6. Write short notes on any four of the following:
(i) Base line extension
(ii) Optical Square
(iv) Differential levelling
(v) Line of collimation
7. (a) The areas enclosed by the contours in a water reservoir are as follows:
Calculate the volume of water between the contours 250 m and 270 m by prismoidal formula.
(b) State the various sources of error in levelling. Briefly discuss the errors arising out of instruments and how to eliminate them.
8. Enumerate the various methods of laying curves. Describe one method in detail with sketches which may be adopted to join an underground haulage roadway bearing N 25° E to a roadway bearing due east with a curve of 45 m radius. What instructions will you give to your workmen?