← Controller of Mines
Past Questions
According to Mizoram Minor Mineral Concession Rules 2000, the period for which a Mining Lease be granted or renewed shall not ordinarily be more than:
A)
5 Years
B)
10 Years
C)
15 Years
D)
20 Years
Under the Mizoram Minor Mineral Concession Rules, 2000, the regulatory framework governs the granting and renewal of mining leases for minor minerals. According to the specific provisions regarding the duration of leases, a Mining Lease is granted for a specific term to ensure sustainable extraction and periodic review by the government. The rules stipulate that the period for which a Mining Lease may be granted or renewed shall ordinarily not exceed 20 years. This timeframe allows the lessee sufficient time to recover capital investments while ensuring the state can re-evaluate the mineral resources and environmental impact at regular intervals. Options a, b, and c are incorrect as they do not align with the statutory limit defined in the 2000 Rules for this specific jurisdiction.
While blasting in hot strata the temperature of hole should not exceed:
A)
50° C
B)
60° C
C)
70° C
D)
80° C
In mining engineering, 'hot strata' refers to rock formations that have high geothermal temperatures or are affected by spontaneous combustion (common in coal mines). When blasting in such environments, the temperature of the borehole is a critical safety factor because high temperatures can lead to the premature detonation or decomposition of explosives, especially those containing nitrates or certain sensitizers. According to standard mining safety guidelines and regulations (such as those derived from DGMS or similar mining safety authorities), the temperature of the hole should not exceed 80°C before charging with explosives to prevent accidental initiation. If the temperature exceeds this limit, cooling measures (like water flushing) must be employed before the explosive is loaded. Options a, b, and c are too conservative and do not represent the standard regulatory threshold for safety limits in hot strata blasting.
Risk Assessment consists of:
A)
Identification of Hazards
B)
Probability of Risk
C)
Risk Rating
D)
All of the above
Risk Assessment is a systematic process used in safety management (especially in mining and industrial environments) to evaluate potential risks that may be involved in a projected activity or undertaking. The process typically follows these fundamental steps:
1. Identification of Hazards (Option a): This is the first step where all potential sources of harm (physical, chemical, biological, etc.) are identified.
2. Probability/Likelihood of Risk (Option b): Once a hazard is identified, the assessor determines the likelihood or probability that the hazard will actually result in an accident or injury.
3. Risk Rating/Evaluation (Option c): This involves combining the probability of occurrence with the severity of the potential consequence (Risk = Probability × Severity) to assign a risk rating (e.g., Low, Medium, High). This rating helps in prioritizing which risks need immediate mitigation.
Since all three components are essential stages of a comprehensive Risk Assessment process, option 'd' is the correct answer.
As per 3rd Schedule of Mines Rule, the number of first aid boxes to be provided in mines shall be @ one for every ‘A’ person employed. ‘A’ is given by:
A)
100
B)
125
C)
150
D)
200
According to the Mine Rules, 1955, specifically the provisions related to first aid and medical appliances (detailed in the 3rd Schedule), it is mandatory for the mine management to provide first aid boxes at strategic locations. The statutory requirement specifies that there shall be one first aid box for every 150 persons employed in the mine. This ensures that medical assistance is readily available and accessible to workers in case of emergencies or injuries during the course of employment. Therefore, 'A' = 150.
Skewness of Normal distribution is:
A)
Negative
B)
Positive
C)
Zero
D)
Undefined
Skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable about its mean.
1. **Definition of Normal Distribution**: A Normal (Gaussian) distribution is defined as a perfectly symmetrical, bell-shaped curve.
2. **Symmetry Property**: In a perfectly symmetrical distribution, the mean, median, and mode are all equal and located at the center of the distribution.
3. **Mathematical Calculation**: Skewness is typically measured by the third standardized moment. For a Normal distribution, the third central moment is zero because for every value above the mean, there is a corresponding equal value below the mean, causing the cubed deviations to cancel each other out.
4. **Analysis of Options**:
- **Negative Skewness (a)**: Occurs when the tail on the left side of the probability density function is longer or fatter than the right side.
- **Positive Skewness (b)**: Occurs when the tail on the right side is longer or fatter than the left side.
- **Zero Skewness (c)**: Occurs when the distribution is perfectly symmetrical, which is the defining characteristic of a Normal distribution.
- **Undefined (d)**: Skewness is well-defined for the Normal distribution.
The dominant frequencies of ground vibration waves recorded within 100 to 500 m from the blasting site are: 8 Hz, 25 Hz, 32 Hz, 6 Hz, 25 Hz, 45 Hz, 16 Hz, 17 Hz. What is the Mode of frequency?
A)
8 Hz
B)
45 Hz
C)
6 Hz
D)
25 Hz
Step 1: Identify the given data set of frequencies: {8, 25, 32, 6, 25, 45, 16, 17}.
Step 2: Understand the definition of 'Mode'. In statistics, the mode is the value that appears most frequently in a data set.
Step 3: Count the occurrences of each value in the set:
- 6 Hz: 1 time
- 8 Hz: 1 time
- 16 Hz: 1 time
- 17 Hz: 1 time
- 25 Hz: 2 times
- 32 Hz: 1 time
- 45 Hz: 1 time
Step 4: Compare the frequencies. The value 25 Hz occurs twice, while all other values occur only once.
Step 5: Since 25 Hz has the highest frequency of occurrence, it is the mode of the data set.
Comparing with options:
- Option a (8 Hz) occurs only once.
- Option b (45 Hz) occurs only once.
- Option c (6 Hz) occurs only once.
- Option d (25 Hz) occurs twice, making it the correct answer.
If S = Summation; Xi = Observations or values; M = Mean; N = number of observations, the formula to calculate the mean deviation (MD) for an individual series is:
A)
1/N Σ |Xi + M|
B)
1/N Σ (Xi - M)
C)
1/N Σ |Xi - M|
D)
1/N Σ (Xi - M)
Mean Deviation (MD), also known as Average Deviation, is a measure of dispersion that calculates the average of the absolute differences between each data point and a central tendency measure (usually the mean or median).
Step-by-step derivation:
1. Find the deviation of each observation (Xi) from the mean (M): (Xi - M).
2. Since some deviations are positive and some are negative, and the sum of deviations from the mean is always zero, we take the absolute value to ensure all distances are positive: |Xi - M|.
3. Sum these absolute deviations for all N observations: Σ |Xi - M|.
4. Divide the total sum by the number of observations (N) to find the average: 1/N Σ |Xi - M|.
Analysis of other options:
- Option (a) uses addition (|Xi + M|), which does not represent a deviation (distance).
- Option (b) and (d) omit the absolute value signs. Without absolute values, the sum Σ (Xi - M) mathematically equals zero, making the result always 0 regardless of the data spread.
Coefficient of variation is a percentage expression of:
A)
Mean deviation
B)
Quartile deviation
C)
Standard deviation
D)
None of the above
Coefficient of variation = (Standard deviation / Mean)*100%, measures relative variability.
Difference between a two-digit number and the number obtained by interchanging the two digits is 36, what is the difference between two numbers
A)
2
B)
4
C)
8
D)
12
Let number 10a+b, diff 9(a-b)=36 => a-b=4. Difference of digits =4.
Choose the correct one:
A)
Redemption is the profit obtained by selling old articles
B)
Redemption is the interest obtained from bank deposit
C)
Redemption is the repayment of a fixed-income security
D)
Redemption is the profit obtained after selling share in stock market
In finance, 'Redemption' refers to the process where an issuer of a debt instrument (such as a bond, debenture, or preference share) repays the principal amount to the holder of the security. This typically occurs at the maturity date of the security.
Analysis of options:
- Option (a) is incorrect: Profit from selling old articles is generally termed as 'Gain on Sale of Assets'.
- Option (b) is incorrect: Interest from bank deposits is simply 'Interest Income'.
- Option (c) is correct: Redemption specifically describes the repayment of the face value of a fixed-income security (like a bond) to the investor.
- Option (d) is incorrect: Profit from selling shares in the stock market is known as 'Capital Gains'.
Dense medium separation (DMS) is a technique used to separate particles based on:
A)
Specific gravity
B)
Hardness
C)
Coarseness
D)
Block size
Dense Medium Separation (DMS) is a gravity-based concentration process used in mineral processing to separate minerals of different densities. The process involves creating a medium (usually a mixture of water and a finely ground heavy mineral like ferrosilicon or magnetite) with a specific density that lies between the densities of the two materials being separated. Particles with a specific gravity lower than the medium will float, while particles with a specific gravity higher than the medium will sink.
Why other options are incorrect:
- b. Hardness: Hardness is a mechanical property (resistance to scratching) and is not used for separation in DMS.
- c. Coarseness: This refers to particle size; while DMS has a specific size range it can operate on, it separates based on density, not size.
- d. Block size: Similar to coarseness, size is a physical dimension and not the driving force for separation in a dense medium environment.
What is the name of the place where the explosives are stored for the purpose of issuing it to an authorized person?
A)
Explosive storage
B)
Reserve station
C)
Magazine
D)
Firing station
In the context of mining and explosives regulations (specifically under the Explosives Rules and Coal Mines/Metal Mines Regulations), different storage facilities serve different purposes:
1. **Magazine**: This is the primary, secure storage facility where explosives are kept in bulk. It is designed with strict safety distances and construction standards to prevent accidental ignition and unauthorized access.
2. **Reserve Station**: This is a temporary storage place (often a smaller, secure facility) where explosives are transferred from the main magazine for the purpose of issuing them to authorized persons (shot-firers) for the day's blasting operations. It acts as an intermediary point between the main bulk storage and the actual site of use.
3. **Firing Station**: This is the location from which the blast is actually triggered; it is not a storage facility.
4. **Explosive storage**: This is a generic term and not a specific regulatory designation for the issuing point.
Therefore, the specific place used for the purpose of issuing explosives to an authorized person is the Reserve Station.
The mean of exponential distribution is given as:
A)
1/l
B)
1/ l2
C)
l2
D)
l3
The exponential distribution is a continuous probability distribution used to model the time between events in a Poisson process. The probability density function (PDF) of an exponential distribution is given by f(x; λ) = λe^(-λx) for x ≥ 0, where λ (represented as 'l' in the options) is the rate parameter.
To find the mean (expected value E[X]), we calculate the integral:
E[X] = ∫₀^∞ x * λe^(-λx) dx
Using integration by parts, this evaluates to:
E[X] = 1/λ
Therefore, the mean of the exponential distribution is the reciprocal of the rate parameter.
- Option (a) 1/l is correct.
- Option (b) 1/l² is the formula for the variance of the exponential distribution.
- Options (c) and (d) are mathematically incorrect for the mean of this distribution.
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.
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.
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.
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.
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.
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.
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.
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 speed of the shock wave within Nonel tube which initiate the blasting cap/detonator at the bottom is about:
A)
1000 m/s
B)
2000 m/s
C)
5000 m/s
D)
7000 m/s
Nonel (Non-Electric) detonating cords and tubes operate using a low-velocity shock wave. Unlike high-explosive detonating cords (which have a core of PETN and travel at speeds of 6,000 to 7,000 m/s), Nonel tubes contain a very small amount of HMX or RDX powder dusted on the inner lining of the plastic tube. This configuration creates a 'dust explosion' or a low-velocity shock wave. The typical propagation speed of this shock wave in a Nonel tube is approximately 2,000 meters per second (m/s). This speed is sufficient to initiate the detonator at the end of the tube but is significantly slower than the detonation velocity of high explosives. Option (a) is too slow, while options (c) and (d) correspond to the velocities of high-explosive detonating cords rather than Nonel tubes.
A conveyor transported the coal at the rate of 220 te/hr is 600 m long moving up a gradient of 1 in 60. If the belt width (W) is 0.75 and cross sectional area of the material is 0.1 W2 along with bulk density of coal is 0.8 t/m3. Calculate the belt speed.
A)
0.04 m/s
B)
0.96 m/s
C)
1.36 m/s
D)
1.89 m/s
To calculate the belt speed, we use the fundamental formula for the capacity of a conveyor belt:
Capacity (Q) = Area of material (A) × Velocity (v) × Bulk Density (ρ)
1. **Identify Given Data:**
- Capacity (Q) = 220 tonnes/hr = 220 / 3600 tonnes/sec ≈ 0.06111 t/s
- Belt Width (W) = 0.75 m
- Cross-sectional Area (A) = 0.1 × W² = 0.1 × (0.75)² = 0.1 × 0.5625 = 0.05625 m²
- Bulk Density (ρ) = 0.8 t/m³
- Length (600 m) and Gradient (1 in 60) are provided but are not required for calculating the speed, as speed depends on the throughput and cross-sectional area.
2. **Rearrange the formula to solve for Velocity (v):**
v = Q / (A × ρ)
3. **Substitute the values:**
v = (220 / 3600) / (0.05625 × 0.8)
v = 0.06111 / 0.045
v ≈ 1.358 m/s
4. **Rounding:**
Rounding 1.358 m/s to two decimal places gives 1.36 m/s.
Therefore, the correct option is (c) 1.36 m/s.