β Controller of Mines
Past Questions β 2023
If the median of noise data collected during day time within the core zone of an opencast mine is 76 dB and its mean value is 72 dB. Then, mode value of noise is
A)
75 dB
B)
84 dB
C)
88 dB
D)
90 dB
To find the mode of the noise data, we use the empirical relationship between mean, median, and mode for moderately skewed distributions. The formula is: Mode = 3(Median) - 2(Mean).
Given values:
Median = 76 dB
Mean = 72 dB
Calculation:
Mode = 3(76) - 2(72)
Mode = 228 - 144
Mode = 84 dB
Therefore, the mode value of the noise is 84 dB. Option (b) is correct. Options (a), (c), and (d) are incorrect as they do not satisfy the empirical relationship for the given mean and median.
As per Mine Rule 1955, in respect of every medical examination, the Manager of the mine concerned shall give at least βBβ days of prior notice in writing to the person to be examined. What is βBβ stand for?
A)
7 days
B)
14 days
C)
20 days
D)
30 days
According to the Mine Rules, 1955, specifically under the regulations governing the Initial Medical Examination (IME) and Periodical Medical Examination (PME) of mine employees, the Manager is responsible for ensuring that employees are notified of their scheduled medical check-ups. The rule explicitly states that the Manager of the mine concerned shall give at least 7 days of prior notice in writing to the person to be examined. This ensures that the employee is aware of the requirement and can make the necessary arrangements to attend the examination. Options b, c, and d are incorrect as they do not align with the statutory notice period specified in the Mine Rules, 1955.
According to Mizoram Minor Mineral Concession Rules 2000, every application for the grant of renewal of the mining lease shall be accompanied by fees of
A)
One hundred rupees
B)
Two hundred rupees
C)
Three hundred rupees
D)
Five hundred rupees
Under the Mizoram Minor Mineral Concession Rules, 2000, the administrative procedures for the grant and renewal of mining leases are clearly defined. Specifically, the rules stipulate that any application submitted for the renewal of a mining lease must be accompanied by a prescribed application fee. According to the fee schedule provided within these rules, the fee for the grant of renewal of a mining lease is set at Two hundred rupees. Options a, c, and d are incorrect as they do not match the statutory fee amount prescribed in the 2000 Rules for this specific action.
The definition of coal under the Coal Mine Regulation (CMR) 2017 is
A)
All organic and inorganic substances
B)
All organic and inorganic substances including natural gas
C)
Both (a) & (b)
D)
anthracite, bituminous coal, lignite, peat and any other form of carbonaceous matter sold or marketed as coal
Under the Coal Mines Regulations (CMR) 2017, the term 'coal' is specifically defined to encompass various grades of carbonaceous materials. According to the regulations, 'coal' means anthracite, bituminous coal, lignite, peat and any other form of carbonaceous matter sold or marketed as coal.
- Option (a) and (b) are incorrect because 'coal' is an organic sedimentary rock; it does not include 'inorganic substances' (such as metals or salts) nor does it include 'natural gas' (which is a gaseous hydrocarbon, whereas coal is a solid fuel).
- Option (c) is incorrect as it relies on the incorrect definitions provided in (a) and (b).
- Option (d) accurately reflects the legal definition provided in the CMR 2017 framework to ensure all marketable forms of solid carbonaceous fuel are regulated under the same safety and operational standards.
The condition for negative skewness is
A)
mode = median = mode
B)
mode < median < mode
C)
mode > median > mode
D)
mode ο£ median ο£ mode
First, it must be noted that the options provided in the original question contain typographical errors (repeating 'mode' instead of 'mean'). In statistics, the relationship between the mean, median, and mode determines the skewness of a distribution.
1. **Symmetrical Distribution**: Mean = Median = Mode.
2. **Positive Skewness (Right-skewed)**: The tail on the right side is longer. The mean is pulled toward the tail, resulting in: Mean > Median > Mode.
3. **Negative Skewness (Left-skewed)**: The tail on the left side is longer. The mean is pulled toward the left, resulting in: Mode > Median > Mean.
Looking at the options provided, Option (c) 'mode > median > mode' is clearly a typo for 'mode > median > mean'. In the context of competitive exams, when such typos occur, the sequence of the inequality signs is the key. For negative skewness, the Mode is the largest value and the Mean is the smallest. Therefore, the sequence Mode > Median > Mean is the correct condition. Option (b) represents positive skewness (Mean > Median > Mode), and Option (a) represents a symmetrical distribution.
In tumbling mills, the ball filling ratio to vessel is
A)
60%
B)
50%
C)
40%
D)
30%
In tumbling mills (such as ball mills or rod mills), the filling ratio refers to the percentage of the mill's internal volume occupied by the grinding media (balls or rods). For optimal grinding efficiency, the mill must not be overfilled or underfilled. If the filling ratio is too high (e.g., 50-60%), the media cannot cascade or cataract effectively, leading to a 'dead zone' in the center and reduced impact energy. If it is too low (e.g., 30%), the media may slide or slip against the liner, causing excessive wear and inefficient grinding. In standard industrial practice for ball mills, the optimal filling ratio typically ranges between 35% and 45%, with 40% being the widely accepted theoretical and practical standard for maximizing the grinding rate and energy efficiency. Therefore, 40% is the most accurate answer among the given options.
To separate two finely divided solids from one another, the process to be selected is
A)
Flotation
B)
washing
C)
Jigging
D)
None of the above
The key phrase in the question is 'finely divided solids.' In mineral processing, the method of separation depends heavily on the particle size of the minerals involved.
1. **Flotation (Option a):** This is a physico-chemical separation process specifically designed for very fine particles (typically ranging from 10 to 100 microns). It relies on the difference in surface hydrophobicity of the minerals rather than density. Because fine particles are dominated by surface forces rather than gravitational forces, flotation is the most effective method for separating finely divided solids.
2. **Washing (Option b):** This is a general term for removing impurities using water. While it can separate materials, it is not a specialized process for 'finely divided' solids and is generally used for coarser materials or surface cleaning.
3. **Jigging (Option c):** Jigging is a gravity separation process that uses the difference in density. However, it is only effective for coarse particles. For very fine particles, the settling velocity is so low (governed by Stokes' Law) that the particles do not settle fast enough to be separated by the pulsing action of a jig, making it unsuitable for finely divided solids.
Therefore, for finely divided solids, flotation is the correct technical choice.
According to MMR 1961, Automatic Contrivance is provided for every shaft or winze exceeding _________ metres in depth.
A)
100
B)
200
C)
300
D)
500
According to the Metalliferous Mines Regulations (MMR), 1961, specifically under the regulations governing winding and hoisting operations, an 'Automatic Contrivance' (often referred to as an automatic brake or safety device to prevent over-winding) is mandatory for every shaft or winze that exceeds 300 metres in depth. This safety mechanism is designed to automatically stop the winding engine or apply brakes if the cage or skip travels beyond its designated limit, thereby preventing catastrophic accidents. Options a (100m), b (200m), and d (500m) are incorrect as they do not align with the specific statutory depth limit defined in the MMR 1961 for this requirement.
According to Mines Rule 1955, what should be the minimum floor area of a shelter in a mine?
A)
8 m2
B)
12 m2
C)
14 m2
D)
20 m2
Under the Mines Rules, 1955, specific standards are laid down for the provision of shelters and amenities for mine workers. According to the regulations regarding the construction and maintenance of shelters (often categorized under the welfare and safety provisions), the minimum floor area required for a shelter is specified as 12 square meters. This ensures that there is adequate space for the workers to take refuge or rest safely. Options a (8 m2), c (14 m2), and d (20 m2) do not align with the statutory minimum requirement stipulated in the 1955 Rules.
Based on the Mines Rule 1955, the initial medical examination of every person employed in the mine should be arranged within a period of βAβ years of the date so notified by the Manager. What is βAβ stand for?
A)
2
B)
3
C)
4
D)
5
According to the Mines Rules, 1955, specifically under the regulations pertaining to the medical examination of persons employed in mines, the initial medical examination (IME) is a mandatory requirement to ensure the fitness of the worker. The rules specify that the initial medical examination of every person employed in the mine should be arranged within a period of 5 years from the date so notified by the Manager. This ensures that all personnel are screened for occupational health risks and general fitness within a reasonable timeframe from the commencement of their employment or the notification of the rule. Therefore, 'A' stands for 5.
Under which section as defined in Mines Act 1952 the central government constitutes a committee for making rules and regulations?
A)
Sec 10
B)
Sec 11
C)
Sec 12
D)
Sec 13
Under the Mines Act 1952, Section 12 specifically deals with the 'Constitution of Advisory Board'. The Central Government is empowered to constitute an Advisory Board to advise on the making of rules and regulations under the Act. This board typically consists of representatives from the government, mine owners, and mine workers to ensure a balanced approach to safety and health regulations.
Breakdown of other sections for clarity:
- Section 10: Generally relates to the appointment of Chief Inspectors and Inspectors.
- Section 11: Relates to the powers of Inspectors to enter and inspect mines.
- Section 13: Relates to the powers of Inspectors to examine persons and call for documents/information.
Therefore, the correct section for the constitution of the committee/board for making rules and regulations is Section 12.
In the Mizoram Minor Mineral Concession Rules 2000, βDead Rentβ means..
A)
Rent payable for every six month of the lease of the Minor Minerals
B)
Rent payable for every year of the lease of the Minor Minerals
C)
Rent payable for every two years of the lease of the Minor Minerals
D)
None of above
Under the Mizoram Minor Mineral Concession Rules 2000, 'Dead Rent' is a standard mining term defined as the minimum rent payable by the lessee to the government for the lease of a mineral area. This payment is mandatory regardless of whether any mineral is actually extracted from the site. In the context of these rules, Dead Rent is calculated and payable on an annual basis (per year). Therefore, option (b) is correct. Options (a) and (c) are incorrect because the statutory period for Dead Rent is annually, not semi-annually or biennially.
As per Reg.177 of MMR 1961, every fence erected on the surface shall be examined by competent person once at least in every _________ days.
A)
14
B)
7
C)
15
D)
30
According to Regulation 177 of the Metalliferous Mines Regulations (MMR), 1961, which deals with the fencing of open excavations and surface openings, it is mandatory that every fence erected on the surface to prevent persons from falling into an open cast working or a shaft/borehole must be examined by a competent person. The regulation specifically stipulates that this examination must take place at least once in every 7 days to ensure the integrity of the fence and the safety of personnel. Therefore, option (b) is the correct answer. Options (a), (c), and (d) are incorrect as they do not align with the statutory time limit prescribed in the MMR 1961.
When the particles of same or different specific gravity come to rest at differential instants, the phenomenon is termed as
A)
stratification
B)
hindered settling
C)
free settling
D)
differential acceleration
In mineral processing and sedimentation, stratification refers to the process where particles of different sizes or specific gravities settle at different rates and come to rest at different times, resulting in the formation of distinct layers (strata) based on their physical properties.
Here is why the other options are incorrect:
- b. Hindered settling: This occurs when the concentration of particles is so high that they interfere with each other's movement, slowing down the settling velocity compared to a single particle.
- c. Free settling: This is the settling of a single particle in a fluid without interference from other particles, governed by Stokes' Law or Newton's Law depending on the Reynolds number.
- d. Differential acceleration: This refers to the initial period when particles of different masses accelerate at different rates before reaching their terminal velocity; it describes the process of reaching steady state, not the final resting state in layers.
Washability test for coal is done by:
A)
float and sink method
B)
hindered settling method
C)
gravitation method
D)
all of the above
Washability tests are conducted to determine the distribution of coal and mineral matter across different density fractions, which helps in designing a coal preparation plant.
1. Float and Sink Method: This is the most fundamental and widely used laboratory method for washability analysis. It involves using liquids of specific gravities to separate coal (which floats) from shale/mineral matter (which sinks).
2. Hindered Settling Method: This is a dynamic separation process where particles settle in a concentrated suspension. It is used both in industrial scale (washers) and in laboratory tests to simulate the behavior of coal in a jig or spiral.
3. Gravitation Method: Both float-sink and hindered settling are essentially forms of gravity separation (gravitation methods), as they rely on the difference in specific gravity between the clean coal and the gangue.
Since all three methods are used to analyze or perform the separation of coal based on density for washability purposes, the correct answer is 'all of the above'.
In normal distribution
A)
mean, median and mode are different to each other
B)
mean, median and mode are equal to each other
C)
Standard deviation and mode are equal
D)
None of the above
A Normal Distribution is a continuous probability distribution that is perfectly symmetrical about its center.
1. **Symmetry**: Because the distribution is bell-shaped and symmetric, the peak of the curve occurs exactly at the center.
2. **Mode**: The mode is the value that appears most frequently (the highest point of the curve). In a normal distribution, this is the center point.
3. **Median**: The median is the middle value that divides the data into two equal halves. Due to symmetry, the center point is the median.
4. **Mean**: The mean is the arithmetic average. In a symmetric distribution, the balance point is exactly at the center.
Therefore, in a perfectly normal distribution, Mean = Median = Mode.
Analysis of other options:
- Option (a) is incorrect because it describes a skewed distribution, not a normal one.
- Option (c) is incorrect because the Standard Deviation measures the spread (width) of the distribution, whereas the mode represents the central location; they are fundamentally different metrics and are not generally equal.
The monetary value of an asset decrease due to
A)
Unfavourable market conditions
B)
Wear and tear
C)
Obsolescence
D)
All of the above
Depreciation is the systematic allocation of the cost of a tangible asset over its useful life. The decrease in the monetary value of an asset can occur due to several factors:
1. Wear and Tear (Option b): This is the most common cause of depreciation. Physical deterioration occurs as an asset is used in operations (e.g., machinery parts wearing out), reducing its efficiency and value.
2. Obsolescence (Option c): An asset may lose value not because it is worn out, but because it has become outdated. This happens due to technological advancements or changes in market demand, making the existing asset less efficient or irrelevant compared to newer models.
3. Unfavourable Market Conditions (Option a): External economic factors, such as a decrease in demand for the product the asset produces or a general decline in the market value of similar assets, can lead to a decrease in the asset's monetary value (often referred to as impairment or market depreciation).
Since all three factors contribute to the reduction of an asset's monetary value, the correct answer is 'All of the above'.
The fine product from classification is known as
A)
slime
B)
slack
C)
tramp
D)
pulp
In mineral processing, classification is the process of separating particles based on their settling velocity in a fluid (usually water), which is a function of size, shape, and density.
1. **Slime (Correct):** The term 'slime' refers to the extremely fine particles (typically less than 10-20 microns) that result from the classification or grinding process. These particles are so small that they remain suspended in the fluid for a long time and are recovered as the 'overflow' or fine product of a classifier.
2. **Slack (Incorrect):** Slacks are small pieces of coal or ore that are too small to be considered 'lumps' but are larger than slimes. They are typically the result of screening rather than classification.
3. **Tramp (Incorrect):** 'Tramp iron' refers to unwanted metallic debris (like broken drill bits or bolts) that accidentally enters the processing plant and must be removed by magnets.
4. **Pulp (Incorrect):** Pulp (or slurry) is the general term for the mixture of crushed ore and water used throughout the processing circuit; it is the feed to the classifier, not the specific fine product.
What should be the minimum period of enforced absence in case of reportable injury according to Mines Act 1952?
A)
24
B)
36
C)
48
D)
72
Under the Mines Act 1952 and the associated Mines Rules, an accident is considered 'reportable' if it results in death or a serious bodily injury which prevents the affected person from reporting for duty for a specific minimum period. According to the statutory definitions for reporting accidents, a 'reportable injury' is one that causes the person to be absent from work for a period of 48 hours or more. If the injury results in an absence of less than 48 hours, it is generally not classified as a reportable injury unless it falls under specific categories of serious accidents. Therefore, the minimum period of enforced absence required to classify an injury as reportable is 48 hours.
For normal distribution which one of the followings statements is true?
A)
mean, median and mode will coincide
B)
mean and median coincide but they are different from mode
C)
mean, median and mode are different from each other
D)
median and mode coincide but they are different from mean
A Normal Distribution is a continuous probability distribution that is perfectly symmetrical about its center.
1. **Symmetry**: Because the distribution is symmetric, the area to the left of the center is equal to the area to the right. This means the center point is the Median (the 50th percentile).
2. **Peak**: The highest point of the bell-shaped curve represents the most frequent value, which is the Mode.
3. **Balance Point**: In a perfectly symmetric distribution, the arithmetic average (Mean) is located exactly at the center of symmetry.
Since the peak, the center of symmetry, and the 50th percentile all occur at the same point in a normal distribution, the Mean, Median, and Mode are identical (they coincide).
- Option b, c, and d are incorrect because they describe skewed distributions. In a positively skewed distribution, Mode < Median < Mean; in a negatively skewed distribution, Mean < Median < Mode.
As per the Explosive Rule, 2008 a tamping rod made entirely of _________ should be used for stemming and charging of shot hole.
A)
Wood
B)
Iron
C)
Steel
D)
all of the above
According to the Explosives Rules, 2008, and general safety standards for blasting operations in mining and quarrying, a tamping rod must be made of a non-sparking material to prevent the accidental initiation of explosives. Wood is a non-conductive and non-sparking material, making it safe for stemming (filling the top of the hole with inert material) and charging. Iron and Steel (options b and c) are ferromagnetic materials that can create frictional sparks when striking the sides of a borehole or the explosive charge itself, which could lead to a premature explosion. Therefore, only wood is the permissible material among the given options.
According to Explosive Rule, 2008 the number of shots, which explode, shall be counted and unless it is certain that all the shots have exploded no person shall approach or be permitted to approach the place until _________ minutes after the firing of shots.
A)
15
B)
20
C)
30
D)
45
According to the safety protocols outlined in the Explosives Rules, 2008 (and aligned with standard mining safety regulations such as the Coal Mines Regulations or Metalliferous Mines Regulations), there is a mandatory waiting period after blasting operations to ensure that all charges have detonated and that no 'misfires' (unexploded shots) are present. The rule specifies that the number of shots which explode shall be counted, and unless it is certain that all shots have exploded, no person shall approach or be permitted to approach the place until 30 minutes after the firing of shots. This waiting period is critical to allow for the dissipation of toxic fumes (blasting gases) and to ensure that delayed-action fuses or malfunctions do not cause accidental detonations when personnel re-enter the area. Options a (15), b (20), and d (45) are incorrect as they do not align with the statutory time limit prescribed in the rules.
Under the Mizoram Minor Mineral Concession Rules 2000, application for grant of mining lease shall be made to Competent Authority or his authorised agents in respect of minor minerals in
A)
FORM A
B)
FORM K
C)
FORM C
D)
FORM D
Under the Mizoram Minor Mineral Concession Rules, 2000, the administrative procedure for obtaining mining rights is strictly defined through specific forms. According to the rules, an application for the grant of a mining lease for minor minerals must be submitted to the Competent Authority (or their authorized agents) using 'FORM A'. This form serves as the primary application document where the applicant provides details regarding the area, the mineral sought, and the credentials of the applicant. Other forms (such as C, D, or K) are typically reserved for different purposes such as transit passes, royalty payments, or specific permits/notifications, but the initial application for a mining lease is consistently designated as Form A.
In the Mines Act 1952, Section 25 deals with
A)
Drinking Water
B)
Medical Appliance
C)
Notice of Certain disease
D)
None of above
Under the Mines Act, 1952, Section 25 specifically mandates the provision of drinking water. It states that every mine shall provide an adequate supply of wholesome drinking water, which shall be sufficiently cooled during hot weather.
Analysis of other options:
- Option (b) Medical Appliances: This is covered under Section 24 of the Mines Act, 1952, which requires the maintenance of first-aid boxes and medical facilities.
- Option (c) Notice of Certain disease: This is covered under Section 26 of the Mines Act, 1952, which deals with the notification of occupational diseases to the Chief Inspector.
Therefore, Section 25 corresponds exclusively to the provision of Drinking Water.
In capital budgeting technique, which one is also known as traditional method of investment appraisal?
A)
Non-discounting technique
B)
Profitability Technique
C)
Discounting technique
D)
None of the above
In Capital Budgeting, investment appraisal techniques are broadly classified into two categories: Traditional (Non-Discounting) methods and Modern (Discounting) methods.
1. **Traditional Methods (Non-Discounting Techniques):** These methods do not consider the 'time value of money'. They assume that a rupee received today is equal to a rupee received in the future. Examples include the Payback Period (PBP) and the Accounting Rate of Return (ARR). Because they ignore the cost of capital and timing of cash flows, they are referred to as traditional or non-discounting techniques.
2. **Modern Methods (Discounting Techniques):** These methods account for the time value of money by discounting future cash flows to their present value. Examples include Net Present Value (NPV), Internal Rate of Return (IRR), and Profitability Index (PI).
Therefore, the 'Non-discounting technique' is the one known as the traditional method of investment appraisal.