Mine Management, Legislation & General Safety
1. How can you properly harness human resource to make mining safe and efficient?
2. Draw up conditions for use of:
(b) Belt Conveyors belowground.
3. What precautions are required to be taken under the Indian Electricity Rules where gas exists?
4. What are the statutory requirements before abandonment of belowground workings? What are dangers from such workings and how can it be reduced?
5. Write short notes on :
(a) Duties of Manager in emergency.
(b) Respirable dust.
(c) Firing of shots near surface structures.
(d) Accident prone mines.
6. What are the improvements necessary for better and safer use of opencast mining machinery?
7. Draw a scheme of safe operating practice with continuous miner. How would you implement it?
8. A moderately thick seam at shallow cover is proposed to be extracted for the first time in the mine by longwall powered support. How would you make a statutory application for extraction and what information are required?
Winning & Working
1. Give the layout and outline a system of fully mechanised modem pillar and stall working. Assume your own conditions.
2. Give layout of an opencast mine having a capacity of 3 million tonnes of coal and 8.5 million m3 of OB per annum worked by shovel dumper combinations. The coal seams are 10-m and 6 m thick respectively with a parting of 6 m to 15m. dipping at 1 in 7 gradient and lying at a depth of 30m to 100m.
Indicate the number and capacity of major earth moving machines. Describe required quality control measures. Assume other necessary data if required.
3. Write notes on:
(a) Condition based monitoring
(b) SMS Blasting
(c) Nonel system of blasting
(d) Productivity and OMS in opencast mines
(e) Plaster shooting
4. Discuss the factors to be taken into consideration regarding the thickness of barriers to be left against a water logged workings. How could it be ensured that thickness of barrier left is ad-equate?
5. Describe with sketches a method that you would recommend for upward boring from underground workings of a coal seam to tap water from an extensive waterlogged goaf 100 meters thickness’ above.
Assume your own conditions. What preparatory arrangement; would you make before commencement of such drilling operation?
What arrangements would you make to control and deal with flow of water through such a hole.
6. Write notes on:
(a) Rib pillar extraction system
(b) Sub level caving
(c) Self-advancing supports
7. A mine has coal seam 7 m thick at a depth of 200 m. Development by bord and pillar method has been done along the floor upto 2m height and it is now decided to carry out final operation by splitting and stowing the bottom portion and caving the top portion. The seam dips at 1 in 7. Explain the method of extraction with suitable sketches and indicate production expected from one such panel.
Assume other suitable data if required.
8. One 3.5m thick degree II gassy seam dipping at 1 in 12, lying at depth of 160 m having sand stone roof and strong floor, is to 1 worked by longwall retreating caving method for an output of 2500 tonnes per day.
Give layout of a longwall panel indicating equipment details, power support to be used, cycle of operation, face organization, dust control measures, ventilation, total investment, productivity and expected cost per tonne of coal production.
Assume suitable data wherever required.
Mine Ventilation, Explosion, Fires & Inundation
1. In a degree one gassy mine, a panel by blasting gallery method is being worked. The incubation period is twelve months and there are incidences of spontaneous heating due to which the panels are sealed off before complete extraction. Analyse the reasons and suggest the preventive measures you would take to work the B.G. panels completely.
2. Write short notes on any four of the following:
(a) Shankey Diagram.
(b) Heat stroke.
(c) Reversal of air current,
(d) Use of foam Nitrogen for control of fires.
(e) Pressure balancing.
3. Explain the procedure for airborne dust survey in mines. According to the statute, what are the places to be sampled and the frequency of sampling? What is the principle of construction of a dust sampler recommended for use in Indian Mines?
4. In a coal mine, a 3.00 m. dia Met in Mechanical Ventilator is providing a quantity of 10,200 m3/min at a W.G. of 54 mm and is consuming 32 Amps of current at 3.3 K.V. Calculate.
(a) The resistance of the ventilation net work.
(b) The equivalent orifice of the ventilation net work.
(c) The Air Power
(d) Overall efficiency of the system.
(e) Power consumption of the fan at a P.F. of 85.
(f) Annual power cost @ Rs. 4.50 per unit.
5. It is proposed to work a mine at 400 m. depth. It is proposed to produce 1.50 million tones/year by deploying 3 Hand Section Drills, 4 nos. Road Headers, 2 nos. of Longwall and one BG panel. (Production from Hand section is 300 TPD and maximum number of persons deployed is 300 in Hand Section in largest shift). Calculate:
(a) The Air quantity required to be delivered by the Main Mechanical Ventilator.
(b) Virgin Rock Temperature.
(c) If the gradient of the seam is 1 in 5, what type of entries would you suggest to meet the ventilation needs the mine?
Required air in BG panel as per permission is 35 m3/sec. You can make other assumption.
6. There is a threat of inundation in your mine from surface as well as UG water. What type of plans you will maintain as a Manager in such a case and what details you would incorporate? Also prepare an organization for dealing with such emergencies.
7. Write short notes on any four of the following:
(a) Methane emission in a coal mine.
(b) Gas chromatograph.
(c) Physiological effect of CO on human beings.
(d) Effect of high wet bulb temperature.
(e) N2 Generator.
(f) Geothermic gradient.
8. Two splits A and B pass 15 and 20 m3/sec, of air respectively with a pressure of 500 Pa. across them. The trunk air-way consumes pressure of 300 pa. Calculate the size of the Regulator required for equalizing the flow in two splits. What will be the flowing air through the mine?
Assume the fan pressure to remain constant.
1. (a) Explain the importance of limit, fit and tolerance in machine design.
(b) Explain with sketch the difference in use of following items in mining machineries.
(i) Key and spline
(ii) ‘O’ ring and oil seal
(iii) Machine bolt and fit bolt
(iv) Circlip and spring washer
(v) Round nut and lock nut
2. Describe an electric rope shovel used in the opencast mines. Assuming your own conditions, calculate annual production capacity of a 10m3 bucket capacity rope shovel.
3. A pump is installed for dewatering a flooded quarry at the rate of 90 litres per second. What diameter of suction and delivery pipes would you install, if the velocities are 2 rn/s and 3.4 m/s for suction and delivery respectively?
Give layout sketch for the proposed pumping installation. Assume your own conditions.
4. What are the different types of man-riding systems used in underground mines? Under what condition each will be applicable and why – discuss.
5. Describe surface miner used in opencast mines. Discuss its merits and limitations.
6. Give layout of a 400 tpd mechanised underground district using trackless machines. Describe coal loading and transporting machine giving reasons for selection. Assume your own conditions.
7. Calculate the size of rope and the drum diameter of a direct-haulage to haul 300 tonnes in 6 hours effective hauling time up an incline 1000 m long having a gradient of 1 in 8. Assume each tub weighs 0.5 tonne and carries 1 tonne of coal. Speed of haulage may be taken as 12 km per hour.
Assume any other necessary data.
8. (a) Discuss selection of a machine for fast gate road development for longwall retreating faces.
(b) What is automatic loop-take up device for gate belt conveyors? Describe with sketch.