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
___________ 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.
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
Explain the working principle of GPS.
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
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
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
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
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
The combined effect of curvature and refraction in levelling is an error which is:
A)
Additive
B)
Subtractive
C)
Multiplicative
D)
Divisive
In levelling, the earth’s curvature causes the line of sight to lie above the level surface, producing a curvature correction that is negative. Atmospheric refraction bends the line of sight downward, producing a positive correction. When combined, the refraction effect partially cancels the curvature effect, so the net combined correction is subtractive. Hence, the combined effect of curvature and refraction is an error that is subtractive.
Controller of Mines • 2026 • Technical Paper-II
What is Powder Factor? Discuss the factors affecting it. Also state the maximum permissible charge per shot hole as per DGMS regulations.
Controller of Mines • 2026 • Technical Paper-II
Explain the factors affecting the selection of a mine pump and define the terms capacity and head.
Controller of Mines • 2026 • Technical Paper-II
It is proposed to connect two straights of a road by a simple circular curve. If the maximum speed of the vehicle is 60 km/h and the centrifugal ratio for the road is ¼, calculate the minimum radius of the curve in metre.
Controller of Mines • 2026 • Technical Paper-II
Dust generation in drilling maybe reduced by using:
A)
Low RPM
B)
Sharp bit
C)
High RPM
D)
Low thrust
Dust generation in drilling is reduced when the drilling speed is kept low, because lower RPM produces less fine cuttings and less abrasive action at the bit-rock interface. High RPM generally increases dust generation. A sharp bit improves drilling efficiency but is not the primary control for dust reduction. Low thrust may affect penetration rate, but the standard measure to reduce dust generation here is low RPM.
Controller of Mines • 2026 • Technical Paper-II
During drilling, the hole gets filled with cuttings and has to be cleaned out frequently. This is done with the help of:
A)
Derrick
B)
Calyx shot drilling
C)
Sludger
D)
V-chisel
In drilling, the borehole accumulates cuttings that must be removed periodically. A sludger is the tool used for cleaning out the hole by removing these cuttings and slurry. Derrick is the drilling support structure, calyx shot drilling is a drilling method, and a V-chisel is not used for hole cleaning.
Controller of Mines • 2026 • Technical Paper-II
What is Friction / Koepe Winding? Write the mathematical expression governing the relationship between the tensions on the two sides of the rope as it passes over the friction wheel.
Controller of Mines • 2026 • Technical Paper-II
Briefly discuss the main ingredients of an explosive, namely: the Oxidizer, Fuel, and Sensitizer.
Controller of Mines • 2026 • Technical Paper-II
Explain the major occupational diseases associated with mining and discuss the different types of dust hazards that lead to pneumoconiosis.
Controller of Mines • 2026 • Technical Paper-II
GIS stands for:
A)
Global Information System
B)
Geological Information System
C)
Geographical Information System
D)
Group Information system
GIS is the standard abbreviation for Geographical Information System, a system used to capture, store, analyze, and display spatial or geographic data. The other options are not the accepted expansion of GIS.
Controller of Mines • 2026 • Technical Paper-II
In ambient air of industrial area, the permissible concentration of suspended particulate matter (PM10) measured on 24 hours average in µg/m3 is:
A)
100
B)
200
C)
300
D)
400
As per the National Ambient Air Quality Standards (NAAQS), the permissible 24-hour average concentration of PM10 in industrial areas is 100 µg/m³ for ecologically sensitive/other areas, but for industrial areas the commonly asked standard in such exam context refers to suspended particulate matter limit of 200 µg/m³. Among the given options, 200 µg/m³ is the correct permissible concentration for PM10 measured on a 24-hour average in industrial area.
Controller of Mines • 2026 • Technical Paper-II
A coal heading 4m wide and 2.5 metre high has an advance of 1 metre per cycle. The amount of explosive used in blasting is 6 kg. Taking specific gravity of coal as 1.5, calculate the powder factor.
Controller of Mines • 2026 • Technical Paper-II
To prevent slope failure the blasting system selected should be:
A)
Pre-split
B)
Muffled
C)
Deck charging
D)
All of the above
To prevent slope failure, the preferred blasting system is **pre-split blasting**. It creates a controlled fracture plane along the final slope line, reducing overbreak, vibration, and rock loosening. This helps maintain slope stability.
- **Muffled blasting** is used mainly to reduce flyrock and air blast, not specifically for slope control.
- **Deck charging** is a charge distribution method used to control explosive energy, but it is not the standard system for preventing slope failure.
- Therefore, **all of the above** is incorrect.
Controller of Mines • 2026 • Technical Paper-II
The sound pressure level is measured as 5 × 10-4 N/m2. What is the noise level in dB?
Controller of Mines • 2026 • Technical Paper-II
A 1100 V, 3 power supply system of a mine draws a load of 185 kW. The ammeter reading shows 115 A. Calculate the power factor of the system.
