Controller of Mines • 2026 • Technical Paper-II
The maximum permissible angle of fleet should not exceed:
A)
1
B)
1.5
C)
2
D)
2.5
In conveyor design, the fleet angle is the angle between the conveyor center line and the line joining the pulley to the belt edge. To avoid belt tracking problems and edge damage, the maximum permissible fleet angle is generally limited to 1.5°. Hence, option (b) 1.5 is correct. Larger angles like 2° or 2.5° are considered excessive, while 1° is more conservative than the standard permissible limit.
Controller of Mines • 2026 • Technical Paper-II
The noise level at 10 m from a long conveyor belt is 95 dBA. What is the noise level at 100 m?
A)
80 dBA
B)
85 dBA
C)
90 dBA
D)
95 dBA
For a long conveyor belt, the noise source behaves approximately like a line source, so sound level decreases by about 3 dB each time the distance is doubled. From 10 m to 100 m is a 10× increase in distance, i.e., about 3.32 doublings. Reduction = 3 × 3.32 ≈ 10 dB. Therefore, 95 dBA − 10 dB = 85 dBA? Wait, for a true long line source the level falls by 10 log10(r2/r1), which gives 10 log10(100/10) = 10 dB reduction, so 95 − 10 = 85 dBA. However, the option set indicates the intended assumption is spherical spreading (point source), where the level drops by 20 dB for a 10× distance increase, giving 95 − 20 = 75 dBA, which is not present. Since conveyor belts are typically treated as line sources, the correct computed value is 85 dBA.
Controller of Mines • 2026 • Technical Paper-II
Detonating chord has a VOD of:
A)
4500-5000 m/s
B)
5500-6000 m/s
C)
6500-7000 m/s
D)
7500-8000 m/s
Detonating cord (detonating chord) typically has a very high velocity of detonation (VOD), commonly around 6,500 to 7,000 m/s. This is why it is used to transmit detonation rapidly and reliably. The other ranges are generally too low for standard detonating cord specifications.
Controller of Mines • 2026 • Technical Paper-II
The noise levels measured during the operation of three machines are 80 dBA, 75 dBA and 85 dBA respectively. Determine the equivalent noise level for the above three machines.
Controller of Mines • 2026 • Technical Paper-II
Explain the concept of ground vibration due to blasting. Discuss the methods of its control and the DGMS permissible limits of Peak Particle Velocity (PPV) for different structures.
Controller of Mines • 2026 • Technical Paper-II
The permissible value of oil and grease discharge from the mine workshop is:
A)
120 mg/L
B)
150 mg/L
C)
220 mg/L
D)
250 mg/L
The prescribed permissible limit for oil and grease in discharge from a mine workshop is 120 mg/L. Therefore, option (a) is correct. The other values—150 mg/L, 220 mg/L, and 250 mg/L—are higher than the standard permissible limit and are not accepted under the usual mine environmental discharge norms.
Controller of Mines • 2026 • Technical Paper-II
Define explosive in the context of Mining Engineering. What are the two main classification of explosive? Give one example each.
Controller of Mines • 2026 • Technical Paper-II
Explain five (5) measurement parameters of Levelling.
Controller of Mines • 2026 • Technical Paper-II
Write a short note on sources of air pollution in mining industries.
Controller of Mines • 2026 • Technical Paper-II
Compared to conventional belt conveyors, high angle conveyors are suitable for:
A)
Long horizontal distance only
B)
Very low speed operation
C)
Steep gradient transport
D)
Fine material handling only
High angle conveyors are designed to carry bulk materials up steep inclines where conventional belt conveyors would slip or require excessive length. They are used for steep gradient transport. The other options are incorrect because conventional belt conveyors are better for long horizontal distance, speed is not the defining feature here, and they are not limited to fine materials only.
Controller of Mines • 2026 • Technical Paper-II
Explain in brief what is Bio-chemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD).
Controller of Mines • 2026 • Technical Paper-II
A coal heading 4m wide and 2.5 m high has an advance of 1 m per blasting round. The amount of explosive used in the blasting round is 6 kg. If the sp.gr of the coal is 1.5. the powder factor is:
A)
2.0 te/kg
B)
2.5 te/kg
C)
3.0 te/kg
D)
3.5 te/kg
Powder factor = quantity of coal broken / quantity of explosive used.
1) Volume blasted per round = width × height × advance = 4 × 2.5 × 1 = 10 m³
2) Density of coal = specific gravity × density of water = 1.5 × 1 = 1.5 t/m³
3) Mass of coal blasted = 10 × 1.5 = 15 tonnes
4) Powder factor = 15 tonnes / 6 kg = 2.5 t/kg
So, the correct answer is 2.5 te/kg.
Other options are incorrect because they do not match the calculated coal-to-explosive ratio.
Controller of Mines • 2026 • Technical Paper-II
In case of opencast mine blasting, the danger zone comprises of area within the diameter of:
A)
400 m
B)
500 m
C)
600 m
D)
300 m
In opencast mine blasting, the prescribed danger zone is generally taken as the area within a diameter of 500 m. This is the standard safety distance used to keep people and structures away from flyrock and blast effects. Therefore, option (b) is correct. The other options do not match the commonly prescribed blasting danger-zone norm.
Controller of Mines • 2026 • Technical Paper-II
The most important parameter of a dust that governs its physiological effect is:
A)
Concentration of dust in air
B)
Shape of dust
C)
Time of exposure
D)
Size of dust
The physiological effect of dust depends most importantly on particle size because it determines how deeply the dust can penetrate into the respiratory system. Fine particles can reach the alveoli and cause more severe health effects, while larger particles are usually trapped in the upper airways. Concentration and exposure time also matter, but particle size is the key governing parameter.
Controller of Mines • 2026 • Technical Paper-II
The limit of explosibility of a mixture of combustible gases can be computed by which of the following equation?
A)
Pythagoras equation
B)
Le Chatelier equation
C)
Simon’s equation
D)
Solmon’s equation
The limit of explosibility of a mixture of combustible gases is computed using the Le Chatelier equation. This rule is used to estimate the lower and upper explosive limits of gas mixtures from the known limits of individual gases. Pythagoras equation is unrelated to gas explosibility, and Simon’s/Solmon’s equations are not the standard formula used for this purpose.
Controller of Mines • 2026 • Technical Paper-II
Which of the following prime characteristic the NONEL blasting has?
A)
It has greater shock to the surrounding.
B)
It is noiseless in character.
C)
It has tremendous effect on explosive column.
D)
It cannot be used in a place where there is a chance of stray current.
NONEL means non-electric blasting system. Its prime characteristic is that it does not use electric current, so it avoids problems like stray current and electromagnetic interference. It is also much quieter in operation compared to electric blasting. Option (d) is incorrect because NONEL is actually preferred where stray current may be present. Options (a) and (c) are not defining characteristics of NONEL blasting.
Controller of Mines • 2026 • Technical Paper-II
Light wave travel with a velocity of:
A)
3 × 1010 cm/s
B)
3 × 1011 cm/s
C)
3 × 1012 cm/s
D)
3 × 1013 cm/s
The speed of light in vacuum is about 3 × 10^8 m/s. Converting to cm/s: 3 × 10^8 m/s × 100 = 3 × 10^10 cm/s. Therefore, option (a) is correct. The other options are too large by factors of 10, 100, and 1000 respectively.
Controller of Mines • 2026 • Technical Paper-II
Explain the working principle of GPS.
Controller of Mines • 2026 • Technical Paper-II
Pop shooting or plaster shooting is a type of:
A)
Primary blasting
B)
Secondary blasting
C)
Muffling
D)
Clay capping
Pop shooting, also called plaster shooting, is used to break oversized boulders after the main blast. That makes it a form of secondary blasting. Primary blasting is the main fragmentation blast, while muffling and clay capping are not the category of pop/plaster shooting.
Controller of Mines • 2026 • Technical Paper-II
Which of the following is the oxidizing agent in an explosive?
A)
Charcoal
B)
Aluminum
C)
Ammonium nitrate
D)
Magnesium carbonate
In an explosive mixture, the oxidizing agent supplies oxygen to support the rapid combustion of the fuel. Ammonium nitrate is a common oxidizer used in explosives. Charcoal acts as a fuel, aluminum is also a fuel in many pyrotechnic/explosive compositions, and magnesium carbonate is not an oxidizing agent in explosives.
Controller of Mines • 2026 • Technical Paper-II
The ground distance between the mine manager’s office and pit top is 300 m and it is represented by 3 cm in the mine plan. What is the representative factor?
Controller of Mines • 2026 • Technical Paper-II
Minimum gradient for Gravity Haulage operation is:
A)
13°
B)
14°
C)
15°
D)
16°
In gravity haulage, the loaded tubs move down under gravity, so a minimum incline is required for the system to work properly. The standard minimum gradient commonly cited for gravity haulage operation is about 13°. Hence, option (a) is correct. The other values are not the usual minimum standard for this type of haulage.
Controller of Mines • 2026 • Technical Paper-II
The method of leveling adopted to determine the difference of level between two points at a considerable distance apart with great precision is:
A)
Hypsometry
B)
Profile levelling
C)
Reciprocal levelling
D)
Trigonometrical levelling
Reciprocal levelling is used to determine the difference in level between two points separated by a considerable distance, especially when obstacles like a river or valley make direct leveling difficult. It also helps eliminate errors due to curvature, refraction, and collimation, giving high precision. Profile levelling is for obtaining levels along a line, hypsometry refers to measuring elevation indirectly, and trigonometrical levelling uses angular measurement but is not the specific method asked here.
Controller of Mines • 2026 • Technical Paper-II
Tractive effort of a locomotive is given by:
A)
W/µ
B)
µ. W
C)
W - µ
D)
W + µ
Tractive effort is the maximum pulling force a locomotive can develop due to adhesion between wheels and rails. It is given by the product of the coefficient of adhesion (µ) and the locomotive weight on driving wheels (W): Tractive effort = µW. Hence, option (b) is correct. Option (a) is incorrect because W/µ would increase as adhesion decreases, which is not physically meaningful. Options (c) and (d) are not the standard formula for tractive effort.
Controller of Mines • 2026 • Technical Paper-II
___________ disease is caused by working in places of insufficient light.
A)
Pneumoconiosis
B)
Ancylostomiasis
C)
Nystagmus
D)
Silicosis
Insufficient light while working, especially in mines, can lead to eye strain and involuntary eye movements called nystagmus. Pneumoconiosis and silicosis are dust-related lung diseases, while ancylostomiasis is caused by hookworm infection, not poor lighting.
