← Controller of Mines
Past Questions
Suspended Particulate Matter (SPM) are solid or liquid having particulate size of:
A)
Less than 10 micron
B)
More than 10 micron
C)
Between 1-10 micron
D)
None of the above
Suspended Particulate Matter (SPM) is a general term used to describe all particles (solid or liquid) suspended in the air, regardless of their size. In environmental engineering and air quality monitoring, SPM typically refers to particles with an aerodynamic diameter of up to 100 microns (μm).
Analyzing the options:
- Option (a) 'Less than 10 micron' refers specifically to PM10 (Particulate Matter 10), which is a subset of SPM.
- Option (b) 'More than 10 micron' refers to coarse particles, which are also a subset of SPM.
- Option (c) 'Between 1-10 micron' refers to a specific range of coarse particles.
Since SPM encompasses the entire spectrum of suspended particles (typically from 0.1 μm up to 100 μm), none of the restrictive ranges provided in options a, b, or c accurately define the total scope of 'Suspended Particulate Matter'. Therefore, 'None of the above' is the most accurate choice.
In the volute casing of the pump the velocity of air gradually decreases but pressure energy increases correspondingly. This happens due to?
A)
Pythagoras theorem
B)
Charles’s law
C)
Hook’s law
D)
Bernoulli’s theorem
The question describes a physical process where the velocity of a fluid (referred to as 'air' in the prompt, though typically liquid in a pump volute) decreases while the pressure increases. This is a direct application of Bernoulli's Principle.
1. **Bernoulli's Theorem**: It states that for an incompressible, non-viscous fluid in steady flow, the sum of pressure energy, kinetic energy, and potential energy per unit volume remains constant. Mathematically: P + 1/2ρv² + ρgh = constant. Therefore, if the velocity (v) decreases, the pressure (P) must increase to maintain the constant sum.
2. **Application in Volute Casing**: The volute casing of a pump is designed with a gradually increasing cross-sectional area. According to the continuity equation (A1V1 = A2V2), as the area increases, the velocity of the fluid decreases. According to Bernoulli's theorem, this decrease in kinetic energy is converted into pressure energy.
Why other options are incorrect:
- **Pythagoras theorem**: A geometric theorem relating the sides of a right-angled triangle; it has no application to fluid dynamics.
- **Charles’s law**: A gas law stating that the volume of a gas is proportional to its absolute temperature at constant pressure.
- **Hook’s law**: A principle of elasticity stating that the force needed to extend or compress a spring is proportional to that distance.
In which of the locomotive there is maximum possibility of formation of CO with exhaust gas?
A)
Diesel loco
B)
Battery loco
C)
Trolley wire loco
D)
Compressed air loco
Carbon Monoxide (CO) is a colorless, odorless, toxic gas produced by the incomplete combustion of carbon-based fuels.
1. **Diesel Loco (Option a):** Diesel locomotives use internal combustion engines that burn diesel fuel. If the combustion process is incomplete (due to factors like low air-fuel ratio, poor engine tuning, or low temperatures), CO is produced as a primary byproduct of the exhaust gases. In underground mining environments, this makes diesel emissions a significant ventilation concern.
2. **Battery Loco (Option b):** These are electric locomotives powered by onboard batteries. They do not involve combustion and therefore do not produce exhaust gases or CO.
3. **Trolley Wire Loco (Option c):** These are electric locomotives powered by an external overhead wire. Like battery locos, they are emission-free at the point of use.
4. **Compressed Air Loco (Option d):** These operate using pneumatic power. The 'exhaust' is simply compressed air being released back into the atmosphere, which contains no CO.
Therefore, only the diesel locomotive involves a combustion process capable of generating Carbon Monoxide.
In which of the following locomotive exhaust conditioner is provided?
A)
Trolley wire locomotive
B)
Diesel locomotive
C)
Compressed air locomotive
D)
Battery locomotive
An exhaust conditioner (also known as an exhaust scrubber or treatment system) is specifically required for diesel locomotives used in underground mines. Diesel engines emit combustion gases, including carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (soot), which are hazardous in confined mine environments. The exhaust conditioner is used to reduce these emissions, cool the exhaust gases, and filter out particulates to ensure the mine air remains within statutory safety limits.
Comparing the options:
- a. Trolley wire locomotives: These are electric and produce no exhaust gases.
- c. Compressed air locomotives: These emit compressed air, which is non-toxic.
- d. Battery locomotives: These are electric and produce no exhaust gases.
Therefore, only the diesel locomotive requires an exhaust conditioner to mitigate pollution.
In the calculation and design of blasting, the controllable parameters are classified as:
A)
Geometric (Diameter, charge length. burden, spacing, etc.)
B)
Physicochemical or pertaining to explosives
C)
Delay timing and initiation sequence
D)
All of the above
In blasting engineering, 'controllable parameters' are the variables that a blasting engineer or technician can adjust to optimize fragmentation, control ground vibration, and ensure safety.
1. **Geometric Parameters (Option a):** These are the physical dimensions of the blast hole and the layout. The engineer can control the hole diameter, the amount of explosive (charge length), the distance to the free face (burden), and the distance between holes (spacing). These directly affect the energy distribution in the rock mass.
2. **Physicochemical Parameters (Option b):** This refers to the selection of the explosive. The engineer can choose between different types of explosives (e.g., ANFO, emulsions, slurries) based on their Velocity of Detonation (VOD), density, and pressure characteristics to match the rock type.
3. **Delay Timing and Initiation Sequence (Option c):** The timing between the detonation of individual holes or rows is a critical controllable factor. By adjusting the delay (using detonators), the engineer can control the direction of the rock throw, reduce peak particle velocity (PPV) to minimize vibrations, and improve fragmentation through stress wave interaction.
Since all three categories are variables that can be intentionally manipulated during the design phase of a blast, the correct answer is 'All of the above'.
In bench blasting, if burden = 4.0 m, Spacing = 5.0 m & Hole depth = 10 m. If the designed specific charge/powder factor is 0.65 kg/m3, what should be the value of explosive charge per hole?
A)
120 kg
B)
130 kg
C)
140 kg
D)
160 kg
To find the explosive charge per hole, we first need to calculate the volume of rock broken by a single blast hole and then multiply it by the specific charge (powder factor).
1. **Calculate the Volume of Rock per Hole (V):**
The volume of rock associated with one hole in bench blasting is calculated as:
Volume = Burden × Spacing × Hole Depth
Given:
Burden (B) = 4.0 m
Spacing (S) = 5.0 m
Hole Depth (H) = 10 m
Volume = 4.0 m × 5.0 m × 10 m = 200 m³
2. **Calculate the Explosive Charge per Hole (Q):**
The explosive charge is calculated by multiplying the volume of rock by the specific charge (powder factor).
Given:
Specific Charge (Powder Factor) = 0.65 kg/m³
Charge per hole = Volume × Specific Charge
Charge per hole = 200 m³ × 0.65 kg/m³ = 130 kg
Therefore, the value of the explosive charge per hole is 130 kg, which corresponds to option (b).
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.
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.
The most common disease of miners due to their exposures to airborne respirable dust is:
A)
Leukemia
B)
Malaria
C)
Pneumoconiosis
D)
Hemorrhoid
Step-by-step reasoning: 1. Analyze the cause: The question specifies 'exposure to airborne respirable dust' in the context of mining. 2. Define Pneumoconiosis: Pneumoconiosis is a general term for a group of interstitial lung diseases caused by the inhalation of certain organic or inorganic dusts, which then settle in the lungs and cause inflammation and scarring (fibrosis). Common types in mining include Coal Worker's Pneumoconiosis (CWP) and Silicosis. 3. Evaluate other options: (a) Leukemia is a cancer of the blood-forming tissues, typically linked to radiation or chemical toxins (like benzene), not respirable dust. (b) Malaria is an infectious disease caused by Plasmodium parasites transmitted via Anopheles mosquitoes. (d) Hemorrhoids are swollen veins in the lower rectum and anus, unrelated to respiratory dust inhalation. 4. Conclusion: Pneumoconiosis is the only option that is a direct result of inhaling respirable dust in a mining environment.
Which of the following clutch is preferably used with direct rope haulage?
A)
Dog clutch
B)
Friction clutch
C)
Centrifugal clutch
D)
All of the above
In direct rope haulage systems, the haulage engine must be capable of handling high torque and providing a positive, slip-free connection to move heavy loads of tubs or conveyors.
1. **Dog Clutch (Correct):** A dog clutch is a positive-engagement clutch that uses interlocking teeth (dogs) to lock the driving and driven shafts together. Because it does not rely on friction, it cannot slip, making it ideal for the heavy-duty, high-torque requirements of direct rope haulage where a secure mechanical lock is necessary to ensure the rope moves the load without slippage.
2. **Friction Clutch (Incorrect):** While common in many machines, friction clutches are prone to slipping under extreme loads. In heavy mine haulage, slippage can lead to wear, overheating, and failure to move the load efficiently.
3. **Centrifugal Clutch (Incorrect):** These are automatic clutches that engage at a specific speed. They are not suitable for haulage systems where precise control over the start, stop, and direction of the rope is required by the operator.
Therefore, the dog clutch is the preferred choice for direct rope haulage due to its positive engagement and ability to transmit maximum torque without slipping.
Stiffness ratio is the ratio of ?
A)
Bench height to burden
B)
Bench height to spacing
C)
Burden to bench height
D)
Hole depth to sub-drill length
In blasting engineering, the Stiffness Ratio (L/B) is a critical parameter used to predict the fragmentation and the movement of the rock mass. It is defined as the ratio of the bench height (L) to the burden (B).
1. **Definition**: Stiffness Ratio = Bench Height / Burden.
2. **Significance**: This ratio determines the mechanism of rock failure. A high stiffness ratio (typically > 3 or 4) generally leads to better fragmentation and more predictable rock movement (heave), as the rock mass behaves more like a rigid block. A low stiffness ratio (typically < 2) often results in excessive toe problems, increased flyrock, and poor fragmentation because the bench is too short relative to the burden to allow the explosive energy to displace the rock efficiently.
Analysis of other options:
- Option b (Bench height to spacing) is not a standard industry ratio used for stiffness.
- Option c (Burden to bench height) is the inverse of the stiffness ratio.
- Option d (Hole depth to sub-drill length) relates to drilling efficiency and toe removal but is not termed the stiffness ratio.
The most common instrument used for dust sampling is:
A)
Velocity dust sample
B)
Accelerator dust sampler
C)
Gravimetric dust sampler
D)
Porosity dust sampler
In industrial hygiene and mining safety, the 'Gravimetric' method is the gold standard and the most common approach for dust sampling.
1. **How it works**: A gravimetric sampler draws air through a filter at a constant flow rate for a specific period. The dust particles are trapped on the filter. The filter is weighed before and after sampling using a high-precision analytical balance. The difference in weight provides the mass of the dust collected, which is then divided by the total volume of air sampled to determine the concentration (mg/m³).
2. **Why it is the most common**: It is a direct measurement of mass, making it highly accurate and the primary reference method for regulatory compliance (such as OSHA or MSHA standards).
3. **Analysis of other options**:
- **Velocity dust sample (a)**: Velocity refers to the speed of air; while air velocity is measured to calibrate samplers, there is no standard instrument called a 'velocity dust sampler' for measuring concentration.
- **Accelerator dust sampler (b)**: This is not a standard term in dust sampling instrumentation.
- **Porosity dust sampler (d)**: Porosity refers to the void space in a material; it is a property of a filter or a rock, not a type of sampling instrument.
In bench blasting, if ‘D’ is the diameter of hole, then burden value generally varies from:
A)
10D to 20D
B)
15D to 25D
C)
25D to 40D
D)
40D to 50 D
In bench blasting, the 'burden' is the distance from the blast hole to the nearest free face. The burden is one of the most critical parameters in blast design because if it is too large, the rock will not break properly (causing excessive vibration and flyrock); if it is too small, the energy is wasted. A widely accepted empirical rule of thumb in mining engineering for determining the burden (B) relative to the hole diameter (D) is that the burden generally ranges from 25 to 40 times the diameter of the hole (B = 25D to 40D). For example, if a hole diameter is 100mm, the burden would typically range between 2.5m and 4.0m depending on the rock type and explosive used. Options a, b, and d represent values that are either too small (leading to excessive flyrock and inefficiency) or too large (leading to poor fragmentation and cratering).
The full form of RDX is:
A)
Reduced Diameter Explosive
B)
Royal Demolition Explosive
C)
Research Department Explosive
D)
Both (b) & (c)
RDX is a powerful military high explosive. Its chemical name is cyclotrimethylenetrinitramine. In technical and historical literature, RDX is known by two primary full forms: 1. 'Research Department Explosive' (referring to its development by the UK's Research Department), and 2. 'Royal Demolition Explosive' (referring to its application in military demolition). Since both options (b) and (c) are widely accepted and historically accurate designations for the substance, option (d) is the correct choice. Option (a) 'Reduced Diameter Explosive' is a fabricated term and is incorrect.
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.
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.
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.
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.
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).
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.
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.
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.
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.