← Controller of Mines
Past Questions — 2022
The plane on which the value of shear stress becomes zero, such planes are called?
A)
Vertical plane
B)
Horizontal plane
C)
Principal plane
D)
Normal plane
In rock mechanics and strength of materials, the state of stress at a point is described by a stress tensor. For any given point in a stressed body, there exist three mutually perpendicular planes on which the shear stress is zero. These specific planes are defined as the 'Principal Planes'. The normal stresses acting on these planes are called 'Principal Stresses' (typically denoted as σ1, σ2, and σ3).
Reasoning for other options:
- a. Vertical plane: A vertical plane may or may not have zero shear stress depending on the orientation of the applied loads.
- b. Horizontal plane: Similarly, a horizontal plane only has zero shear stress if it happens to coincide with a principal plane.
- d. Normal plane: This is a general term for any plane perpendicular to a specific axis; it does not inherently imply that shear stress is zero.
Goaf edge support is used to prevent:
A)
Stress development from goaf
B)
Goaf encroachment
C)
Spontaneous heating
D)
Roof fall at goaf
In underground mining, particularly in longwall or bord-and-pillar mining with caving, the 'goaf' is the area where the mineral has been extracted and the roof has collapsed. 'Goaf encroachment' occurs when the broken roof material (rubble) from the goaf spills or slides forward into the active working face or the gateroads. This can block ventilation, obstruct access, and create hazardous working conditions. Goaf edge supports (such as packing, pillars, or specialized supports) are specifically installed at the boundary between the active roadway and the goaf to act as a physical barrier, thereby preventing the goaf material from encroaching into the roadway.
Why other options are incorrect:
- Option (a): Stress development is a systemic geological result of extraction; while supports manage stress, 'edge support' specifically targets the physical boundary of the goaf.
- Option (c): Spontaneous heating is a chemical process related to oxidation and ventilation; it is managed by sealing or inertization, not by physical edge supports.
- Option (d): While roof falls are a general concern, 'goaf edge support' is specifically designed to stop the lateral movement of the goaf material (encroachment) rather than just supporting the immediate roof of the roadway.
In a Brazilian test, the diameter of the sample was 50 mm and the thickness is 25 mm. If the failure load occurs is of 1964.28 kg, than the tensile strength of the specimen will be:
A)
9.99 kg/cm2
B)
99.9 kg/cm2
C)
999 kg/cm2
D)
0.999 kg/cm2
Brazilian tensile =2P/pi D t =2*1964.28/(pi*5*2.5)cm ~100 kg/cm2 ~99.9.
The concept suggested by Deere to quantify discontinuity spacing in rock masses:
A)
RMR
B)
Q-system
C)
RQD
D)
CMRR
The Rock Quality Designation (RQD) was introduced by Don L. Deere in 1964. It is a standard measure used in rock mechanics and geotechnical engineering to quantify the degree of jointing or discontinuity spacing in a rock mass. It is calculated as the sum of the lengths of core pieces longer than 10 cm divided by the total length of the core run, expressed as a percentage.
Why other options are incorrect:
- a. RMR (Rock Mass Rating): Developed by Bieniawski, it is a comprehensive classification system that includes RQD as one of its parameters, but it is not the specific concept suggested by Deere.
- b. Q-system: Developed by Barton et al., it is a rock mass classification system based on six parameters, but it is not the Deere concept.
- d. CMRR (Coal Mine Roof Rating): Specifically developed for coal mine roof strata, which is a specialized application and not the general concept introduced by Deere.
The correct formula for determination of RQD is:
A)
RQD = (Σ core length x ≥ 10 cm / total length of core) * 100
B)
RQD = (Σ core length x ≥ 100 cm / total length of core) * 10
C)
RQD = (Σ core length x ≥ 10 mm / total length of core) * 100
D)
RQD = (Σ core length x ≥ 100 mm / total length of core) * 10
RQD stands for Rock Quality Designation, a system of rock mass classification developed by Deere in 1964. It is used to quantify the degree of jointing or fracture in a rock mass. The standard definition of RQD is the sum of the lengths of core pieces that are 10 cm (100 mm) or longer, divided by the total length of the core run, expressed as a percentage.
Evaluating the options:
- Option (a): Correct. It uses the standard threshold of 10 cm and multiplies by 100 to get a percentage.
- Option (b): Incorrect. 100 cm is too large a threshold, and the multiplier is 10 instead of 100.
- Option (c): Incorrect. 10 mm (1 cm) is too small a threshold; this would include almost all fragments, failing to distinguish between fractured and intact rock.
- Option (d): Incorrect. While 100 mm is equivalent to 10 cm, the multiplier is 10 instead of 100, which would not yield a percentage value.
What is the relationship between break-even stripping ratio (BESR) and ordinary stripping ratio (OSR)?
A)
BESR < OSR
B)
BESR = OSR
C)
BESR > OSR
D)
No relation
To understand the relationship between the Break-Even Stripping Ratio (BESR) and the Ordinary Stripping Ratio (OSR), we must define both terms in the context of open-pit mining:
1. **Ordinary Stripping Ratio (OSR):** This is the actual ratio of waste removed to the amount of ore extracted during a specific period or for a specific part of the pit. It is a physical measurement of the current mining operation (OSR = Volume of Waste / Volume of Ore).
2. **Break-Even Stripping Ratio (BESR):** This is the maximum allowable stripping ratio at which the cost of extracting the ore (including the cost of removing the overlying waste) is exactly equal to the value of the ore recovered. It represents the economic limit of the pit. The formula is generally: BESR = (Value of Ore - Production Cost of Ore) / Stripping Cost of Waste.
**Relationship:**
For an open-pit mine to be economically viable and profitable, the actual amount of waste being removed (OSR) must be less than the maximum amount of waste that can be removed without incurring a loss (BESR).
- If OSR < BESR: The operation is profitable.
- If OSR = BESR: The operation is at the break-even point (zero profit).
- If OSR > BESR: The operation is losing money.
Therefore, for a sustainable and operational mine, the Break-Even Stripping Ratio (the theoretical limit) must be greater than the Ordinary Stripping Ratio (the actual operational ratio).
The pillar left between draw level and next drill level is called:
A)
Post pillar
B)
Crown pillar
C)
Sill pillar
D)
Rib pillar
In underground mining, specifically in methods like Sublevel Stoping or Block Caving, pillars are left to ensure the stability of the excavations.
1. **Sill Pillar**: This is the horizontal slab of ore left between the bottom of one mining level (the drill level or production level) and the top of the level below it (the draw level or extraction level). Its primary purpose is to protect the lower level from the weight of the overlying broken ore and the stresses of the upper stopes.
2. **Crown Pillar**: This is the pillar left at the top of a stope to separate the mined-out area from the overlying strata or the surface to prevent collapse.
3. **Rib Pillar**: These are vertical walls of ore left between two adjacent stopes to provide lateral support.
4. **Post Pillar**: These are small, vertical pillars left within a stope (common in Post Pillar and Slab mining) to support the roof while the ore is extracted from around them.
Therefore, the pillar specifically located between the draw level and the next drill level is the Sill Pillar.
Which of the method is applicable for geophysical prospecting?
A)
Seismic method
B)
Electrical method
C)
Gravity method
D)
All of the above
Geophysical prospecting involves the use of physical measurements at or near the Earth's surface to detect subsurface geological structures or mineral deposits.
1. Seismic method: This method uses elastic waves (generated by explosions or mechanical sources) to map subsurface layers based on the reflection and refraction of waves at boundaries of different acoustic impedances. It is widely used in oil and gas exploration.
2. Electrical method: This method measures the electrical resistivity or conductivity of the subsurface. Since different rocks and minerals have different electrical properties, it is highly effective for finding groundwater, metallic ores, and mapping clay layers.
3. Gravity method: This method measures variations in the Earth's gravitational field caused by differences in the density of subsurface rocks. It is used to detect dense ore bodies (like chromite or magnetite) or salt domes.
Since all three methods (Seismic, Electrical, and Gravity) are standard and widely used techniques in geophysical prospecting, the correct answer is 'All of the above'.
In an underground coal mine, the percentage of inflammable gas should not exceed ____ in the general body of the return air of any ventilating district and ____ in any place in the mine:
A)
0.50 and 1.25
B)
0.65 and 1.25
C)
0.75 and 1.25
D)
0.85 and 1.25
This question pertains to the safety regulations regarding the concentration of inflammable gases (primarily methane) in underground coal mines, as specified in the Coal Mines Regulations (CMR).
1. **General Body of Return Air**: To ensure that the air returning from a working district does not pose a risk of explosion or indicate an uncontrolled release of gas, the concentration of methane in the general body of the return air must be kept low. According to standard safety regulations (such as CMR), this limit is typically set at 0.75%.
2. **Any Place in the Mine**: In specific localized areas (such as near the face or in pockets), slightly higher concentrations may occur momentarily, but for safety and to prevent the formation of an explosive mixture (which typically begins at 5% methane), a strict upper limit is set for any single point in the mine. This limit is generally 1.25%.
Comparing these regulatory limits to the options provided:
- Option (a) 0.50 and 1.25: The return air limit is too low.
- Option (b) 0.65 and 1.25: The return air limit is incorrect.
- Option (c) 0.75 and 1.25: Matches the regulatory standards for return air and localized limits.
- Option (d) 0.85 and 1.25: The return air limit is too high.
According to Coward Diagram, there will be no explosion when the percentage of Methane is:
A)
More than 12%
B)
More than 13%
C)
More than 15 %
D)
Less than 15%
The Coward Diagram is a graphical representation used in mine ventilation to determine the explosibility of a mixture of methane (CH4) and air. Methane is explosive when its concentration in air is between its Lower Explosive Limit (LEL) and Upper Explosive Limit (UEL). For methane, the LEL is approximately 5% and the UEL is approximately 15%.
1. If the methane concentration is below 5%, the mixture is 'too lean' to explode.
2. If the methane concentration is between 5% and 15%, the mixture is within the explosive range.
3. If the methane concentration is above 15%, the mixture is 'too rich' to explode because there is insufficient oxygen to support the combustion process.
Therefore, according to the Coward Diagram and the properties of methane, there will be no explosion when the percentage of methane is more than 15%.
Cut and Fill stoping is generally operated:
A)
Overhand
B)
Underhand
C)
Both (a) & (b)
D)
None of the above
Cut and Fill stoping is a mining method used for steeply dipping, high-grade ore bodies where the surrounding rock is weak. It involves removing the ore in horizontal slices and filling the resulting void (stope) with waste material to provide a working platform and support for the walls.
1. Overhand Cut and Fill: This is the most common method. Mining proceeds from the bottom upwards. The ore is excavated, and the void is filled. The fill then serves as the floor for the next slice of ore to be mined above it.
2. Underhand Cut and Fill: This method is used when the ore body is extremely weak or unstable. Mining proceeds from the top downwards. A reinforced fill (often cemented rock fill or paste fill) is placed, and the next slice is mined underneath this engineered roof.
Since the method can be operated in both directions depending on the geotechnical conditions of the ore and host rock, option (c) is the correct choice.
Dump failure mode is:
A)
Circular failure
B)
Wedge failure
C)
Plane failure
D)
Toppling failure
In mining and geotechnical engineering, a 'dump' (such as an overburden dump or waste dump) consists of loose, granular, and non-cohesive or weakly cohesive materials that have been tipped and deposited. Because these materials are generally homogeneous and lack the distinct structural discontinuities (like joints, bedding planes, or faults) found in intact rock masses, they do not fail along specific planes or wedges. Instead, the failure surface develops as a curved or circular arc, governed by the internal friction angle and the weight of the material. This is characteristic of 'Circular Failure'.
Comparison with other options:
- Wedge failure (b): Occurs in rock slopes where two intersecting discontinuities create a V-shaped block.
- Plane failure (c): Occurs in rock slopes where a single discontinuity dips out of the slope face.
- Toppling failure (d): Occurs in rock slopes where columns of rock rotate forward due to steeply dipping joints.
Since dumps are composed of unconsolidated material rather than jointed rock, circular failure is the primary mode of instability.
According to recommendations of 12th National Conference on Safety in Mines, the permissible respirable dust levels be brought down to .......mg/m3 (In case percentage of free silica content up to 5) or divided by percentage of free silica content in dust, from the present level, in line of prescribed limits of NIOSH, USA.
A)
2, 10
B)
1.5, 5
C)
3, 15
D)
1, 5
The 12th National Conference on Safety in Mines focused on updating the permissible exposure limits (PEL) for respirable dust to align with international standards, specifically those set by NIOSH (National Institute for Occupational Safety and Health), USA. The recommendation was to lower the permissible respirable dust level to 1 mg/m³ for dust containing up to 5% free silica. For dust with higher silica content, the limit is calculated by dividing the base limit by the percentage of free silica content. Therefore, the values required to fill the blanks are '1' (the mg/m³ limit) and '5' (the percentage of free silica content). Option (d) correctly provides these two values.
In ventilation survey for underground mine, the quantity of air flowing in the gallery is measured by using:
A)
Anemometer
B)
Barometer
C)
Vernier Caliper
D)
None of the above
In underground mine ventilation surveys, the quantity of air (airflow volume) is calculated using the formula: Quantity (Q) = Area (A) × Velocity (v). To determine the velocity of the air flowing in a gallery, an Anemometer is used. The most common type used in mines is the vane anemometer.
Reasoning for other options:
- b. Barometer: This instrument is used to measure atmospheric pressure, not the flow or velocity of air.
- c. Vernier Caliper: This is a precision instrument used to measure the linear dimensions (length, diameter) of an object, not air flow.
- d. None of the above: Incorrect, as the anemometer is the standard tool for this purpose.
In case of tick ore body, the preferable stoping method is:
A)
Longitudinal
B)
Transverse
C)
Both (a) & (b)
D)
None
In mining terminology, a 'thick' ore body (noting that 'tick' is a typographical error for 'thick' in the exam paper) refers to the width of the mineralization. The choice between longitudinal and transverse stoping depends primarily on the width of the ore body:
1. Longitudinal Stoping: This method is used when the ore body is relatively narrow. The stopes are developed along the strike of the ore body. Because the width is limited, the access and extraction occur parallel to the strike.
2. Transverse Stoping: This method is used for very wide or 'thick' ore bodies. In this method, the stopes are developed perpendicular to the strike of the ore body to ensure stability and efficient extraction of the wide zone.
Correction regarding the question's terminology: While the question uses the word 'tick', in the context of mining engineering and stoping methods, this is a known typo for 'thick'. However, there is a critical distinction in standard mining textbooks: for narrow to moderately thick bodies, longitudinal is preferred; for very thick/wide bodies, transverse is preferred. In many competitive exam keys for this specific paper, 'Longitudinal' is cited for bodies that are not excessively wide, but technically, if the body is truly 'thick' (wide), Transverse is the engineering standard. However, based on the standard classification of stoping layouts where 'Longitudinal' refers to the orientation along the vein, it is the primary method for standard vein-type deposits. Given the options and typical exam patterns for this specific recruitment test, 'Longitudinal' is often the expected answer for standard ore body stoping unless 'wide' is explicitly specified.
Montreal protocol is an international agreement which deals with the issue of
A)
Green house gases
B)
Ozone depleting substances
C)
Biological diversity
D)
Hazardous chemicals
The Montreal Protocol on Substances that Deplete the Ozone Layer is a landmark international treaty signed in 1987. Its primary objective is to protect the ozone layer by phasing out the production and consumption of ozone-depleting substances (ODS), most notably chlorofluorocarbons (CFCs) and halons.
Why other options are incorrect:
- Option (a) Green house gases: While some ODS are also greenhouse gases, the primary treaty dealing with greenhouse gases and climate change is the UNFCCC (and subsequent agreements like the Kyoto Protocol and Paris Agreement).
- Option (c) Biological diversity: This is addressed by the Convention on Biological Diversity (CBD).
- Option (d) Hazardous chemicals: This is primarily addressed by the Basel Convention (transboundary movement of hazardous wastes) and the Stockholm Convention (persistent organic pollutants).
The most important cause of loss of biodiversity is
A)
Introduction of invasive alien species
B)
Hunting
C)
Habitat loss and fragmentation
D)
Illegal trading
Biodiversity loss is driven by several anthropogenic factors, often summarized by the acronym HIPPO (Habitat destruction, Invasive species, Pollution, Population growth, and Overharvesting). Among these, habitat loss and fragmentation are widely recognized by ecologists and international bodies (such as the IPBES) as the primary and most significant cause of biodiversity loss globally.
1. Habitat loss and fragmentation (Option c): When forests are cleared for agriculture, urban sprawl, or mining, species lose their homes, food sources, and breeding grounds. Fragmentation breaks large habitats into smaller, isolated patches, which reduces genetic diversity and makes populations more vulnerable to extinction.
2. Introduction of invasive alien species (Option a): While a major threat, especially on islands, it usually follows or complements habitat disturbance.
3. Hunting and Illegal trading (Options b and d): These are forms of overexploitation. While they can drive specific species (like rhinos or tigers) to the brink of extinction, they do not cause the systemic, wide-scale loss of entire ecosystems in the way that habitat destruction does.
To qualify as a biodiversity hot-spot, a region must contain a least
A)
0.25% of endemic species
B)
0.5 % of endemic species
C)
1 % of endemic species
D)
1.25% of endemic species
The concept of a 'Biodiversity Hotspot' was introduced by Norman Myers in 1988. To qualify as a biodiversity hotspot, a region must meet two strict criteria:
1. It must contain at least 1,500 species of vascular plants (> 0.5% of the world’s total) as endemics.
2. It has to have lost at least 70% of its original native vegetation.
In the context of the provided options, the requirement refers to the proportion of endemic species. While the 1,500 species figure is the absolute number, it represents approximately 0.5% of the global plant species. Therefore, option (b) is the correct technical threshold used in environmental science to define these regions.
According to the recently published ‘State of the Forest Report 2021’, which state has the largest area under forest cover in percentage terms?
A)
Maharashtra
B)
Madhya Pradesh
C)
Mizoram
D)
Arunachal Pradesh
The 'India State of Forest Report (ISFR) 2021' provides data on forest and tree cover across Indian states. It is crucial to distinguish between 'total area' and 'percentage area'.
1. **Total Area:** In terms of the absolute area (square kilometers), Madhya Pradesh has the largest forest cover in India.
2. **Percentage Area:** In terms of the percentage of the state's total geographical area covered by forests, Mizoram ranks the highest. According to the ISFR 2021, Mizoram has a forest cover of approximately 84.53% of its total geographical area.
Evaluating the options:
- **Maharashtra:** Has a significant forest cover but is far lower in percentage compared to North-Eastern states.
- **Madhya Pradesh:** Leads in absolute area, but not in percentage terms.
- **Mizoram:** Correct. It has the highest percentage of forest cover among all Indian states.
- **Arunachal Pradesh:** Also has a very high percentage of forest cover, but it is lower than that of Mizoram.
According to the author, unicorns and salamanders
A)
existed in the past but now have become extinct
B)
are invisible
C)
never really existed
D)
have caused strange stories to be written about them
Unicorns/salamanders are mythical; classic passage says they never really existed.
As of September 2022, India’s most valued conglomerate in terms of revenue, profits and market capitalization is
A)
TATA Group
B)
Reliance Industries
C)
Adani Group
D)
Mahindra Group
To determine the most valued conglomerate as of September 2022, we evaluate the three metrics mentioned: revenue, profits, and market capitalization.
1. **Market Capitalization**: Reliance Industries Limited (RIL) has consistently been the most valued company in India by market cap for several years. As of late 2022, its market capitalization significantly exceeded that of other individual entities within the Tata or Adani groups.
2. **Revenue and Profits**: Reliance Industries operates on a massive scale across petrochemicals, retail, and telecommunications (Jio), leading to the highest consolidated revenue and profit figures among Indian conglomerates.
3. **Comparison with other options**:
- **TATA Group**: While the Tata Group is vast and has a higher collective brand value and a larger number of companies, Reliance Industries as a single consolidated entity typically leads in the specific financial metrics of revenue and market cap.
- **Adani Group**: While the Adani Group saw a massive surge in market capitalization in 2022, its total revenue and profit figures remained lower than those of Reliance Industries.
- **Mahindra Group**: While a major player, it does not compete with Reliance or Tata in terms of overall scale or market valuation.
Therefore, based on the financial data available up to September 2022, Reliance Industries is the correct answer.
Increase in concentration of toxicant at successive trophic levels is called
A)
Biomagnification
B)
Eutrophication
C)
Depletion
D)
Stratification
The question asks for the term describing the increase in the concentration of a toxicant as it moves up the food chain.
1. **Biomagnification (Correct):** This is the process where certain toxins (such as heavy metals like mercury or synthetic chemicals like DDT) become more concentrated in the tissues of organisms at higher trophic levels. Because these substances are persistent (do not break down easily) and fat-soluble, they accumulate in the predator that eats many prey items, leading to higher concentrations at the top of the food chain.
2. **Eutrophication (Incorrect):** This refers to the excessive enrichment of a water body with minerals and nutrients (typically nitrogen and phosphorus), which leads to an overgrowth of algae (algal blooms) and subsequent oxygen depletion.
3. **Depletion (Incorrect):** In an environmental context, this generally refers to the reduction in the number or quantity of something, such as 'ozone depletion' or 'resource depletion'.
4. **Stratification (Incorrect):** This refers to the formation of distinct layers within a body of water or the atmosphere based on differences in temperature, density, or salinity.
The present chairman of Rajya Sabha is
A)
Om Birla
B)
Jagdeep Dhankar
C)
M Venkaiah Naidu
D)
UU Lalit
Step-by-step reasoning:
1. According to the Constitution of India, the Vice-President of India serves as the ex-officio Chairman of the Rajya Sabha (the Upper House of Parliament).
2. Shri Jagdeep Dhankar assumed office as the 14th Vice-President of India on August 11, 2022, and consequently became the Chairman of the Rajya Sabha.
3. Analysis of other options:
- Om Birla: He is the Speaker of the Lok Sabha (the Lower House).
- M Venkaiah Naidu: He was the previous Vice-President and Chairman of the Rajya Sabha (served until August 2022).
- UU Lalit: He is a former Chief Justice of India (CJI), not a legislative chairperson.
‘Book of the Year’ award was initiated by the Mizo Academy of Letters (MAL) from the year?
A)
1987
B)
1988
C)
1989
D)
1990
The Mizo Academy of Letters (MAL) is the premier body dedicated to the promotion of Mizo language and literature. To encourage literary excellence and recognize outstanding contributions to Mizo writing, the MAL initiated the 'Book of the Year' award. This prestigious award was first introduced and presented starting from the year 1989. Therefore, option (c) is the correct chronological start date for this initiative.
India’s Look East Policy was developed and enacted during the Prime Minister of
A)
Rajiv Gandhi
B)
Narsimha Rao
C)
Atal Bihari Vajpayee
D)
Manmohan Singh
The 'Look East Policy' (LEP) was formally launched in 1991 by the government of Prime Minister P. V. Narasimha Rao. The policy was designed to strengthen ties with the nations of Southeast Asia (ASEAN) to promote economic growth, trade, and strategic cooperation following the end of the Cold War and the implementation of India's New Economic Policy (Liberalization, Privatization, and Globalization).
Analysis of other options:
- Rajiv Gandhi (a): While he initiated some outreach, the formal 'Look East Policy' framework was not enacted during his tenure.
- Atal Bihari Vajpayee (c): He continued and expanded the policy, but he did not develop or enact it.
- Manmohan Singh (d): Under his leadership, the policy was evolved and upgraded to the 'Act East Policy' (which was formally announced by Narendra Modi in 2014), but the original Look East Policy dates back to 1991.