← Controller of Mines
Past Questions — 2022
Degree of accuracy in primary triangulation is:
A)
1 in 500000
B)
1 in 50000
C)
1 in 100000
D)
1 in 250000
In surveying, triangulation is categorized into different orders based on the required precision and the scale of the map to be produced. Primary triangulation (also known as First-Order triangulation) is the highest level of accuracy used to establish a national control network. The standard degree of accuracy (relative error) for primary triangulation is generally accepted as 1 in 250,000.
- Primary Triangulation: Accuracy is approximately 1 in 250,000.
- Secondary Triangulation: Accuracy is lower, typically around 1 in 50,000.
- Tertiary Triangulation: Accuracy is further reduced to suit local mapping needs.
Therefore, option (d) is the correct technical standard for primary triangulation.
If the number of persons employed in the mine is 500 then the quantity of water required is:
A)
2000 lit
B)
1000 lit
C)
500 lit
D)
1500 lit
According to the Mine Regulations (specifically referring to the standards for drinking water and sanitation in mining operations), the prescribed requirement for drinking water is typically 4 liters per person per shift/day to ensure health and hygiene in the working environment.
Calculation:
Number of persons = 500
Water requirement per person = 4 liters
Total water required = 500 persons × 4 liters/person = 2000 liters.
Therefore, for 500 employees, the total quantity of water required is 2000 liters. Options b, c, and d are incorrect as they provide quantities that fall below the standard health and safety requirements for a workforce of this size.
For dewatering in case of sudden inundation, the type of pump used is:
A)
Face pump
B)
Turbine pump
C)
Submersible pump
D)
Vertical drill pump
In the event of sudden inundation (flooding) in a mine, the water level rises rapidly, often submerging the pump installation area. A submersible pump is specifically designed to operate while completely immersed in water. Unlike other pumps, it does not require priming and can be deployed quickly into the flooded area to begin pumping water out immediately.
Analysis of other options:
- Face pumps (a) are typically used for localized drainage at the working face but are not designed for large-scale sudden inundation where the pump itself may be submerged.
- Turbine pumps (b) are generally used for high-head pumping from sumps but require a specific installation setup and are not as versatile for rapid deployment in sudden flood scenarios.
- Vertical drill pumps (d) is not a standard term for primary dewatering pumps in this context; drill pumps are used for drilling operations, not mine dewatering.
In the base line measurement of triangulation survey the correction for sag is:
A)
Always Positive
B)
Always negative
C)
Cumulative
D)
None of the above
In surveying, specifically during base line measurement using a tape or chain, 'sag' occurs when the tape is supported only at its ends. Due to its own weight, the tape forms a catenary curve rather than a perfectly straight line. Because the actual distance measured along the curved tape is longer than the straight-line distance between the two points, the recorded measurement (the 'read' value) is always greater than the actual horizontal distance. To find the true distance, a correction must be subtracted from the measured length. Since the correction is subtracted, it is mathematically defined as a negative correction.
- Option (a) is incorrect because a positive correction would imply the measured length was shorter than the actual distance.
- Option (c) is incorrect because 'cumulative' refers to errors that persist in the same direction throughout a series of measurements (like a tape being too short), whereas sag is a specific physical correction based on the tension and weight of the tape for a specific span.
- Option (d) is incorrect as option (b) is the standard technical fact in surveying.
Which one is the technique of controlled blasting?
A)
Staggered bench blasting
B)
Cast blasting
C)
Pre-splitting
D)
None of the above
Controlled blasting refers to specialized blasting techniques used to minimize damage to the remaining rock wall (the final wall) and to reduce ground vibrations and flyrock.
1. **Pre-splitting (Option c):** This is a primary technique of controlled blasting. It involves drilling a row of closely spaced holes along the final excavation limit and firing them before the main production blast. This creates a fracture plane (a 'split') that reflects the shockwaves from subsequent production blasts, protecting the final wall from overbreak and instability.
2. **Staggered bench blasting (Option a):** This refers to a pattern of hole placement (geometry) used to improve fragmentation in production blasting, rather than a technique specifically designed to control the stability of the final wall.
3. **Cast blasting (Option b):** This is a high-energy blasting technique used to move the bulk of the blasted rock (muckpile) a significant distance away from the face to reduce loading and hauling costs. It is a production technique, not a controlled blasting technique for wall preservation.
Therefore, Pre-splitting is the only option that fits the definition of a controlled blasting technique.
The algebraic sum of the deflection angles of a closed n- sided traverse is equal to:
A)
2n + 4right angles
B)
2n – 4right angles
C)
360°
D)
2n right angles
In surveying, a deflection angle is the angle by which a traverse line deviates from the extension of the preceding line. For a closed traverse, the surveyor eventually returns to the starting point, meaning the total change in direction must complete a full circle to close the loop. Mathematically, the algebraic sum of the deflection angles (where angles in one direction, e.g., clockwise, are positive and angles in the opposite direction, e.g., counter-clockwise, are negative) must equal ±360°.
To distinguish this from interior angles:
1. The sum of interior angles of a closed n-sided polygon is (2n - 4) right angles.
2. The sum of exterior angles is (2n + 4) right angles.
3. However, the 'algebraic sum' of deflection angles specifically refers to the net rotation required to close the traverse, which is always 360° regardless of the number of sides (n).
When the open pit mines are refilled with the tailings is called as:
A)
Pond storage
B)
Extraction
C)
Beneficiation
D)
Processing
In the context of mine reclamation and waste management, 'Pond storage' (specifically in-pit tailings disposal) refers to the practice of refilling an exhausted open pit mine with tailings (the waste materials remaining after the processing of ore). This method is often preferred over surface tailings dams because it reduces the risk of dam failure and utilizes existing voids in the landscape.
Analysis of other options:
- b. Extraction: This is the process of removing the mineral or ore from the earth, which is the opposite of refilling.
- c. Beneficiation: This is the process of improving the chemical or physical properties of the ore (e.g., crushing, grinding, flotation) to separate the valuable mineral from the gangue.
- d. Processing: This is the broad term for the chemical or mechanical treatment of ore to extract the metal, which produces the tailings in the first place.
The permissible error for correlation by wires in two shafts is:
A)
± 18 of arc
B)
± 28 of Arc
C)
± 58 of Arc
D)
None of the above
In mine surveying, the correlation of two shafts (connecting the surface or underground workings of two different shafts) is a critical operation to ensure the accuracy of the mine plan. One of the traditional methods used for this is the 'correlation by wires' (also known as the wire-line method). According to standard mining surveying regulations and technical guidelines (often cited in Indian mining regulations and textbooks like those by S.K. Saha), the permissible error for the correlation of two shafts using the wire method is generally specified as ± 18 seconds of arc (often written as ± 18"). This strict tolerance is necessary to prevent significant positional errors when extending underground galleries over long distances. Options b and c provide values (28 and 58) that exceed the standard permissible limits for high-precision shaft correlation.
Trough shape of the belt conveyor is made with the help of :
A)
Bottom roller
B)
Idlers
C)
Drive roller
D)
Snub pulley
In a belt conveyor system, the 'trough shape' is specifically designed to prevent material spillage and increase the carrying capacity of the belt. This is achieved using 'Troughing Idlers'. Troughing idlers consist of a set of three or more rollers (idlers) arranged in a V-shape or U-shape. As the belt passes over these angled rollers, it conforms to their shape, creating a trough that holds the bulk material securely.
Why other options are incorrect:
- a. Bottom roller: These are typically used on the return side of the belt to support it and keep it aligned; they are flat and do not create a trough.
- c. Drive roller: The drive pulley provides the mechanical force to move the belt; it is cylindrical and does not shape the belt into a trough.
- d. Snub pulley: A snub pulley is used to increase the wrap angle of the belt around the drive pulley to improve friction and prevent slippage; it does not create a trough shape.
To mark the river, lake tank, pond etc., on mine plane so as to take precautions against inundation the survey to be done by-
A)
Traversing
B)
Correlation
C)
Levelling
D)
Triangulation
In mine surveying, 'Correlation' refers to the process of correlating underground mine workings with surface features. To prevent inundation (flooding), it is critical to accurately map the position of surface water bodies (rivers, lakes, tanks, ponds) relative to the underground excavations. Correlation surveys involve transferring surface coordinates and elevations to the mine plan to ensure that the mine workings do not breach the water-bearing strata or the bottom of a water body.
Why other options are incorrect:
- Traversing (a): This is a method of establishing control points by measuring distances and angles; while used in surveying, it is a general technique, not the specific process of linking surface water bodies to mine plans.
- Levelling (c): This is used to find the vertical height/elevation of points. While necessary for correlation, levelling alone does not 'mark' the spatial relationship between surface features and underground workings.
- Triangulation (d): This is a method for establishing a large-scale horizontal control network using triangles; it is not the specific process used for inundation prevention mapping.
What is the neutral pH?
A)
6.0
B)
7.0
C)
7.5
D)
8.0
The pH scale is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It is defined as the negative logarithm (base 10) of the molar concentration of hydrogen ions ([H+]) in a solution: pH = -log10[H+].
1. At 25°C (standard room temperature), pure water undergoes self-ionization where [H+] = [OH-] = 10^-7 mol/L.
2. Plugging this into the formula: pH = -log10(10^-7) = 7.0.
3. A pH of 7.0 is defined as 'neutral' because the concentration of acidic ions (H+) and basic ions (OH-) are exactly equal.
Analysis of options:
- Option (a) 6.0: This is less than 7, making the solution acidic.
- Option (b) 7.0: This is the exact point of neutrality.
- Option (c) 7.5: This is greater than 7, making the solution slightly basic (alkaline).
- Option (d) 8.0: This is greater than 7, making the solution basic (alkaline).
Detaching safety hooks are used only in:
A)
Drum winders
B)
Koepe winders
C)
Both drum and koepe winders
D)
None of the above
In mining winding systems, there are two primary types of winders: Drum winders and Koepe (Friction) winders.
1. Drum Winders: In a drum winder, the rope is wound onto a drum. If an overwind occurs, the rope simply unwinds from the drum or reaches the end of the drum, and the cage is stopped by safety catches or the rope breaks.
2. Koepe (Friction) Winders: These use a friction drive where the rope passes over a drive pulley. Because the rope is continuous (often looped) and the system relies on friction, an overwind situation can be catastrophic. If a cage is over-wound in a Koepe system, it can be pulled into the sheave wheel or the headgear structure, potentially causing the rope to snap or the entire system to collapse.
To prevent this, 'Detaching Safety Hooks' are installed. These hooks are designed to automatically detach the rope from the conveyance (cage/skip) when the conveyance is pulled beyond a certain limit (over-wound). This prevents the conveyance from being pulled into the machinery and protects the structural integrity of the headgear. Therefore, detaching safety hooks are a specific safety requirement for Koepe winders and are not used in standard drum winding systems.
In which unit sound is measured?
A)
Kilometer
B)
Pascal
C)
Kilogram
D)
Decibel
Sound intensity and sound pressure levels are measured using a logarithmic scale called the decibel (dB). This scale is used because the human ear can perceive a vast range of sound pressures.
Analysis of options:
- a. Kilometer: This is a unit of distance/length.
- b. Pascal: This is the SI unit of pressure. While sound is a pressure wave, the 'level' of sound (loudness/intensity) as commonly measured in noise pollution contexts is expressed in decibels.
- c. Kilogram: This is a unit of mass.
- d. Decibel: This is the standard unit used to measure the intensity of sound and noise pollution levels.
The combined effect of curvature and refraction in levelling is an error which is:
A)
Additive
B)
Subtractive
C)
Multiplicative
D)
Divisive
In leveling, two primary natural errors affect the line of sight over long distances: Curvature and Refraction.
1. **Curvature of the Earth**: The Earth's surface curves away from the horizontal line of sight. This causes the staff reading to be higher than it would be on a flat plane. Therefore, the error due to curvature is additive (it increases the apparent reading), and the correction is subtractive.
2. **Atmospheric Refraction**: The atmosphere bends the line of sight downwards toward the Earth's surface. This causes the staff reading to be lower than it would be in a vacuum. Therefore, the error due to refraction is subtractive, and the correction is additive.
3. **Combined Effect**: The curvature error is significantly larger than the refraction error. The combined correction (C) is given by the formula: C = 0.0673 × D² (where D is distance in km). Since the curvature effect (which makes the reading too high) dominates the refraction effect (which makes the reading too low), the net result is that the staff reading is still too high.
However, the question asks about the 'combined effect' in terms of how the two errors interact. Because refraction acts in the opposite direction to curvature, it partially cancels out the curvature error. In the context of the total error calculation, the refraction error is subtracted from the curvature error. Thus, the combined effect of refraction on the curvature error is subtractive.
The minimum gradient for direct rope haulage is:
A)
1 in 10
B)
1 in 11
C)
1 in 12
D)
1 in 14
In mine haulage systems, 'direct rope haulage' refers to a system where the tubs are pulled directly by a rope attached to a winding engine. The gradient (slope) of the haulage road is a critical factor for safety and efficiency. If the gradient is too steep, the risk of 'runaway' tubs increases, and the braking system may fail to hold the load. In standard mining engineering practice and regulatory guidelines for rope haulage, the minimum gradient (meaning the steepest permissible slope or the limit beyond which specific safety measures are required) for direct rope haulage is generally considered to be 1 in 12. Gradients steeper than 1 in 12 (e.g., 1 in 10) are typically avoided for direct haulage due to the high risk of accidents and excessive wear on the rope and braking mechanisms. Therefore, 1 in 12 is the standard benchmark for the minimum safe gradient in this context.
If the track gauge of underground haulage is 0.6 m, radius of curve 2 m, velocity of train is 2 m/sec. What will be the amount of super elevation?
A)
0.02
B)
0.12
C)
0.22
D)
0.32
To calculate the super elevation (cant) of a track, we use the formula derived from the balance of centrifugal force and the component of gravity:
Formula: e = (G * v²) / (g * R)
Where:
- e = Super elevation (m)
- G = Track gauge (m) = 0.6 m
- v = Velocity of the train (m/s) = 2 m/s
- g = Acceleration due to gravity (approx. 9.81 m/s², often taken as 10 m/s² in competitive exams for simplification)
- R = Radius of the curve (m) = 2 m
Calculation using g = 10 m/s²:
e = (0.6 * 2²) / (10 * 2)
e = (0.6 * 4) / 20
e = 2.4 / 20
e = 0.12 m
Calculation using g = 9.81 m/s²:
e = (0.6 * 4) / (9.81 * 2)
e = 2.4 / 19.62
e ≈ 0.1223 m
Comparing the result with the given options, 0.12 matches perfectly. Therefore, the amount of super elevation required is 0.12 m.
In the classification of explosives, the “Category - Z” means:
A)
Explosive having a mass explosion risk and major missile effect
B)
Explosive having high VOD, but low gas energy
C)
Explosive having sympathetic detonation with high gap sensitivity
D)
Low explosives having velocity of detonation less than 2000 m/s
In the classification of explosives (specifically referring to the hazard classification systems used in mining and explosives storage regulations, such as those aligned with UN and international safety standards), explosives are categorized based on their risk of mass explosion and the potential for producing missiles (fragments).
- Category Z (or Hazard Division 1.1 in broader UN terms) typically refers to explosives that have a mass explosion hazard, meaning there is a risk that the entire load will detonate almost instantaneously, often accompanied by a significant missile effect (projection of fragments).
- Option b is incorrect as VOD (Velocity of Detonation) and gas energy are performance characteristics, not the primary basis for the 'Category Z' safety classification.
- Option c refers to sympathetic detonation, which is a property of sensitivity, not the defining characteristic of Category Z.
- Option d describes low explosives (deflagrating explosives), whereas Category Z is associated with high explosives capable of mass detonation.
Which of the following is not a physical characteristic of mine water pollution?
A)
Colour
B)
pH
C)
Odour
D)
Temperature
Water quality characteristics are generally categorized into physical, chemical, and biological parameters.
1. Physical Characteristics: These are properties that can be perceived by the senses (sight, smell, touch) or measured physically without changing the chemical identity of the substance. Examples include:
- Colour: Visible change due to dissolved minerals or suspended solids (e.g., orange hue from iron oxides in acid mine drainage).
- Odour: Smells resulting from dissolved gases or organic matter.
- Temperature: The thermal state of the water, which affects oxygen solubility and aquatic life.
- Turbidity and Total Suspended Solids (TSS).
2. Chemical Characteristics: These involve the chemical composition and reactivity of the water.
- pH (Potential of Hydrogen): This is a measure of the acidity or alkalinity of the water. It is a chemical property because it describes the concentration of hydrogen ions [H+] in the solution, representing a chemical state rather than a physical attribute.
Therefore, while colour, odour, and temperature are physical characteristics, pH is a chemical characteristic.
The ‘temperature inversion’ of the atmosphere in surface mines aggravates the problem of:
A)
airborne dust
B)
noise
C)
ground vibrations
D)
visibility
Step-by-step reasoning: 1. Understanding Temperature Inversion: Normally, air temperature decreases with altitude. In a 'temperature inversion', a layer of warm air sits on top of a layer of cooler air near the surface. 2. Atmospheric Stability: This warm layer acts as a 'lid' or cap, preventing the vertical mixing of air. This creates a highly stable atmospheric condition. 3. Impact on Pollutants: In surface mines, activities like blasting, hauling, and drilling generate significant amounts of airborne dust (particulate matter). Under normal conditions, these particles disperse upward into the atmosphere. However, during an inversion, the dust is trapped near the ground because it cannot penetrate the warmer air layer above. 4. Aggravation: Because the dust is trapped in a concentrated layer near the surface, the local concentration of airborne dust increases significantly, aggravating air quality and health hazards. 5. Evaluating other options: (b) Noise and (c) Ground vibrations are mechanical waves; while atmospheric conditions can slightly refract sound, inversion does not 'aggravate' them in the same fundamental way it traps pollutants. (d) Visibility is a result of the dust/fog, but the primary 'problem' being aggravated by the atmospheric trapping mechanism is the presence of the airborne pollutants themselves.
Angle of fleet should not be more than:
A)
1.5°
B)
1.6°
C)
1.7°
D)
1.8°
In mine haulage and ropeway engineering, 'fleet angle' refers to the angle between the center line of the drum and the center line of the rope as it leads to the first sheave (pulley). If the fleet angle is too large, it causes the rope to rub against the flanges of the sheave or the drum, leading to excessive wear, fraying of the rope, and potential derailment or snapping. According to standard engineering practices for mine haulage and hoisting systems, the maximum permissible fleet angle for a smooth-drum system is generally kept below 1.5° to 2.0°. In the context of specific technical examinations for mining controllers and standard haulage guidelines, 1.8° is recognized as the upper permissible limit to ensure the longevity of the wire rope and the efficiency of the winding mechanism. Options a, b, and c are within the safe range, but the question asks for the maximum limit ('should not be more than'), making 1.8° the correct threshold.
Aerosols consisting of solid particles produced by combustion is known as:
A)
Fog
B)
Smog
C)
Smoke
D)
None of these
Step-by-step reasoning: 1. Definition of Aerosols: Aerosols are suspensions of fine solid particles or liquid droplets in a gas (usually air). 2. Analyzing 'Smoke': Smoke is specifically defined as a collection of airborne solid and liquid particulates, primarily consisting of carbon or other combustion products, emitted when a material undergoes combustion. Since the question specifies 'solid particles produced by combustion', smoke is the precise term. 3. Evaluating other options: (a) Fog is an aerosol consisting of liquid water droplets suspended in the air, formed by condensation, not combustion. (b) Smog is a type of intense air pollution that is a mixture of smoke and fog (or ozone and particulates), rather than the primary combustion particles themselves. Therefore, 'Smoke' is the most accurate answer.
The tangential method of tachometry is generally used when the diaphragm having-
A)
2 additional horizontal hairs
B)
2 additional hairs
C)
No stadia hairs
D)
None of the above
Tachometry is the branch of surveying used to determine horizontal distances and elevations using an optical instrument. There are two primary methods: the Stadia Method and the Tangential Method.
1. **Stadia Method**: This is the most common method. It requires a diaphragm equipped with two additional horizontal hairs (called stadia hairs) located above and below the central crosshair. The distance is calculated based on the intercept between these two hairs on a leveling staff.
2. **Tangential Method**: This method is employed specifically when the telescope is NOT equipped with stadia hairs (i.e., the diaphragm has no stadia hairs). Instead of measuring an intercept on a staff, the surveyor takes two separate angular readings (vertical angles) to two different points on the staff. The horizontal distance is then calculated using trigonometric identities based on these two angles and the difference in the staff readings.
Therefore, the tangential method is the alternative used when the instrument lacks the necessary stadia hairs for the standard stadia method.
As per governing laws of the pump, the relationship between water quantity (Q) and rotation of impeller (rpm) is:
A)
Q = rpm
B)
Q a rpm
C)
Q > rpm
D)
Q a 1/rpm
The relationship between the flow rate (Q) and the rotational speed of the impeller (N or rpm) is governed by the 'Pump Affinity Laws'. According to these laws, the discharge or water quantity (Q) is directly proportional to the speed of the impeller. Mathematically, this is expressed as Q1/Q2 = N1/N2, or Q ∝ N. In the provided options, 'a' is used as a symbol for proportionality (∝). Therefore, Q ∝ rpm (represented as Q a rpm) is the correct relationship.
Analysis of other options:
- Option (a) Q = rpm is incorrect because they are not numerically equal; they are proportional.
- Option (c) Q > rpm is incorrect as it describes a comparison of magnitude rather than a functional relationship.
- Option (d) Q a 1/rpm is incorrect because it suggests an inverse relationship, whereas increasing the speed of a pump increases the flow rate.
An electric cap lamp as used in mines has a fuse of capacity:
A)
1 amp
B)
2 amp
C)
3 amp
D)
4 amp
In mining safety standards, electric cap lamps are designed to be intrinsically safe or flameproof to prevent the ignition of methane or coal dust. Because cap lamps operate on low-voltage battery systems (typically 3.6V to 5V) and consume very low current to power an LED or small bulb, the circuit must be protected by a very low-capacity fuse to ensure that any internal short circuit does not lead to overheating or sparking. A 1 amp fuse is the standard capacity used in these devices to provide adequate protection while allowing the lamp to function normally. Higher capacities (2A, 3A, or 4A) would be too high to protect the delicate circuitry and the battery from thermal runaway or sparking in a hazardous underground environment.
Based on Schedule-1, “Nitro-Compound” comes under the explosive classification of:
A)
Class-1
B)
Class-2
C)
Class-3
D)
Class-4
Under the Explosives Act and the associated Explosives Rules (which govern the classification of explosives in India and similar jurisdictions), explosives are categorized into different classes based on their chemical composition and properties.
1. Class-1 typically refers to gunpowder or black powder.
2. Class-2 refers to Nitro-compounds (such as TNT, Nitrocellulose, and other nitrate-based organic compounds).
3. Class-3 typically refers to Chlorates, Perchlorates, and other similar salts.
4. Class-4 typically refers to other explosives not covered in the previous classes.
Since 'Nitro-Compound' is explicitly listed under the classification for Class-2 in Schedule-1 of the regulatory framework for explosives, option (b) is the correct answer.