JNTU
JNTU B.Tech II DRILLING AND BLASTING Previous Question Paper (April/May - 2023 - R15)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
Write briefly limitations of drilling.
Answer
The primary limitations of drilling operations include high operational costs due to equipment maintenance, fuel consumption, and labor requirements. Additionally, drilling is restricted by the geological complexity of the rock mass, such as the presence of voids, faults, or extreme hardness, which can cause bit deviation, slow penetration rates, and increased tool wear.
Briefly explain the scope of drilling in mining.
Answer
Drilling serves as the fundamental primary operation in surface and underground mining, providing the essential space required for the placement of explosives. Its scope encompasses several critical functions:
- Fragmentation Preparation: Drilling creates precise boreholes that dictate the distribution of explosive energy, which is vital for achieving the desired rock fragmentation and muckpile characteristics.
- Exploration and Sampling: It is used for exploratory drilling to determine geological structures, ore grade distribution, and rock mass properties, which inform mine planning and design.
- Operational Support: Beyond blasting, drilling is essential for secondary purposes such as installing roof bolts for ground support, providing ventilation channels, and creating drainage holes in underground workings.
Ultimately, the efficiency of the drilling operation directly influences the overall cost-effectiveness and safety of the entire mining cycle by optimizing downstream activities like loading, hauling, and crushing.
List the different names of drill bits.
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Explain the factors effecting the drilling.
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What are the SMS explosives and their applications?
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Classify various detonators.
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State briefly blasting efficiency.
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Explain broadly the computational model of blasting.
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Briefly explain the environmental effects of blasting.
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Classify any software using for fragmentation analysis.
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Part B
Explain different drilling methods, and present their merits and demerits.
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Distinguish between wire line drilling and directional drilling with diagrammatically.
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Discuss the properties of borehole logging. Explain novel and special drilling techniques.
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Compare between Horizontal and directional drilling methods.
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Describe the method of rotary drilling, Write note on design and selection of drills.
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Explain the following: i) Thrust ii) R P M iii) Flushing.
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Illustrate the merits and demerits of rotary drilling over percussive drilling.
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Explain the conditions of drill hole economics.
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Describe the accessories of safety fuses and detonating cords.
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Briefly present the sequential blasting machines and other shot firing tools.
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State and explain the SMS and EMS explosives. What are the advantages of delay detonators?
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State and explain relays. Write their advantages and dis-advantages.
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Differentiate between smooth blasting, and induced blasting.
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Explain the statutory requirements of underground blasting.
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Describe the concept of wedge cut pattern of drilling and applications.
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State and explain solid blasting. Mention which type of explosives used in solid blasting.
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Illustrate the properties of primary and secondary blasting, and fragmentation studies in open pit.
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Discuss applications and techniques of controlled blasting and its types.
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What are the applications and techniques to be adopted for demolition of a building?
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Demonstrate the methods of dimensional stone blasting, and explain to prevent water pollution from blasting in opencast mining.
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