81. During blasting operations, rock fragmentation occurs due to:

1. Reflection of the compressive wave generating tensile and shear wave

2. High vibration frequency

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer: (a)

82. Which of the following statements are correct regarding machine tools?

1. A pillar drilling machine drills holes upto 70 mm

2. A regulating wheel is a component of any surface grinding machine

3. A sensitive drilling machine is also known as the bench drilling machine

(a) 1 and 2 only

(b) 1 and 3 only

(c) 2 and 3 only

(d) 1, 2 and 3

Answer: (b)

83. Hoskold’s formula is relevant for:

(a) Mine valuation

(b) Ore reserve estimation

(c) Depreciation calculation

(d) Salting

Answer: (a)

84. Which one of the following statements is correct?

(a) DTH is a rotary drill

(b) Jack Hammer is a percussive drill

(c) DTH is a rotary- cum- percussive drill

(d) Jack Hammer is a rotary- cum - percussive drill

Answer: (b)

85. Which one of the following statements is correct?

(a) Drag bits and button bits are used in rotary drills

(b) Chisel bits and roller bits are used in percussive drills

(c) Cross bits and drag bits are used in rotary drills

(d) Chisel bits and button bits are used in percussive drills

Answer: (d)

86. Rock Texture Coefficient, TC , is calculated by using the following formula 

AW refers to:

(a) Grain size

(b) Grain packing weighting

(c) Hardness coefficient

(d) Aspect ratio

Answer: (b)

87. ‘Drillability of Rocks’ is premised on:

1. Specific energy required

2. New surface area created

3. Heat generated during drilling

(a) 1, 2 and 3

(b) 1 and 3 only

(c) 1 and 2 only

(d) 2 and 3 only

Answer: (c)

88. Which of the following theories relate to rock drilling operations?

1. Ernst & Merchant theory

2. Evans theory

3. Nishimatsu’s theory

4. Solomon theory

(a) 2, 3 and 4 only

(b) 1, 2 and 4 only

(c) 1, 3 and 4 only

(d) 1, 2 and 3 only

Answer: (d)

89. Which of the following methods qualify as electrical logging?

1. Spontaneous potential logging

2. Resistivity logging

3. Sonic logging

4. Induction logging

(a) 2, 3 and 4 only

(b) 1, 3 and 4 only

(c) 1, 2 and 4 only

(d) 1, 2 and 3 only

Answer: (c)

90. Which of the following statements are correct?

1. Electromagnetic methods are suitable for ore body of poor conductivity

2. Resistivity methods are suitable for ore body of poor conductivity

3. Potential Drop Ratio methods are suitable for ore body of poor conductivity

4. Electromagnetic methods are suitable for ore body of high conductivity

(a) 2, 3 and 4 only

(b) 1 and 3 only

(c) 2 and 4 only

(d) 1, 2 and 3 only

Answer: (a)