← Controller of Mines
Past Questions
In emulsion explosive, one of the chemical/ingredient is not included. What is that chemical/ingredient?
A)
Ammonium nitrate
B)
Water
C)
Emulsifying agent
D)
Nitroclycerine
Emulsion explosives are a type of water-in-oil emulsion. Their composition typically consists of: 1) Ammonium Nitrate (the primary oxidizer), 2) Water (used to dissolve the ammonium nitrate), and 3) An emulsifying agent (used to stabilize the mixture of the aqueous oxidizer solution and the fuel/oil phase). Nitroglycerine is the primary ingredient in dynamite (a gelatinous explosive), but it is specifically excluded from emulsion explosives to make them safer to handle, more stable, and less sensitive to accidental detonation. Therefore, Nitroglycerine is not an ingredient in emulsion explosives.
Which of the following are major environmental issues involved in mining?
A)
Air pollution
B)
Water pollution
C)
Soil degradation
D)
All of the above
Mining activities have comprehensive negative impacts on the environment, affecting air, water, and land.
1. Air Pollution: Mining operations generate significant amounts of particulate matter (dust) from blasting, drilling, and transportation. Additionally, smelting processes associated with mining release sulfur dioxide and other toxic gases into the atmosphere.
2. Water Pollution: Mining often leads to Acid Mine Drainage (AMD), where sulfide minerals are exposed to air and water, creating sulfuric acid that leaches heavy metals into nearby streams and groundwater. Chemical spills from processing plants also contaminate water bodies.
3. Soil Degradation: Open-cast mining involves the removal of topsoil and vegetation (overburden), leading to the complete loss of fertile soil layers, increased soil erosion, and contamination of the land with toxic tailings and chemicals.
Since all three options (a, b, and c) are recognized as major environmental consequences of mining, the correct answer is 'All of the above'.
Carbon monoxide has more affinity with haemoglobin than oxygen for about:
A)
2000 times
B)
100 times
C)
210 times
D)
20 times
Carbon monoxide (CO) has a significantly higher affinity for hemoglobin (Hb) than oxygen (O2) does. When CO binds to hemoglobin, it forms carboxyhemoglobin (COHb), which prevents the transport of oxygen to tissues and inhibits the release of any bound oxygen. In toxicology and medical literature, the relative affinity of hemoglobin for CO compared to O2 is generally cited as being between 200 and 250 times greater. Among the given options, '210 times' falls precisely within this scientifically accepted range. Option (a) 2000 times is an exaggeration, while options (b) 100 times and (d) 20 times are too low to account for the extreme toxicity of carbon monoxide even at low atmospheric concentrations.
Which of the following is not a geometric controllable parameter of blasting ?
A)
Burden
B)
Spacing
C)
Type of explosive
D)
Hole depth
In blasting engineering, parameters are categorized into geometric (spatial/dimensional) and non-geometric (material/chemical/temporal) parameters.
1. Geometric parameters refer to the physical dimensions and spatial arrangement of the blast holes. These include:
- Burden (the distance from a blast hole to the nearest free face).
- Spacing (the distance between adjacent blast holes in a row).
- Hole depth (the vertical or inclined length of the drilled hole).
- Stemming length and Sub-drilling.
2. Non-geometric parameters refer to the properties of the materials used or the timing of the blast. These include:
- Type of explosive (which determines the velocity of detonation and gas pressure).
- Powder factor (amount of explosive per unit volume of rock).
- Delay timing (the sequence in which holes fire).
Since 'Type of explosive' is a material property and not a spatial dimension, it is not a geometric controllable parameter.
The full form of COD is:
A)
Chemical Oxygen Demand
B)
Chemically Oxygen Demand
C)
Chemistry Oxygen Demand
D)
None of the above
In water quality analysis, COD stands for Chemical Oxygen Demand. It is a critical measure used to determine the amount of oxygen required to chemically oxidize the organic and inorganic matter in a water sample. This is typically achieved using a strong oxidizing agent (such as potassium dichromate) under acidic conditions.
Analysis of options:
- Option (a) 'Chemical Oxygen Demand' is the standard scientific term used globally in environmental engineering and chemistry.
- Option (b) 'Chemically Oxygen Demand' is grammatically incorrect as 'Chemical' (adjective) is required to modify the noun phrase 'Oxygen Demand'.
- Option (c) 'Chemistry Oxygen Demand' is incorrect as 'Chemistry' is the name of the field of study, not the descriptor for the type of demand.
Total error in latitude and departure is distributed in proportion to the lengths of the sides by:
A)
Transit rule
B)
Reversal point rule
C)
Centesimal rule
D)
Bowditch rule
In surveying, when a closed traverse is plotted, the sum of latitudes and departures should theoretically be zero. However, due to measurement errors, a 'closing error' often occurs. To balance the traverse, this error must be distributed among the sides.
1. **Bowditch Rule (Compass Rule):** This rule states that the correction to be applied to the latitude or departure of a side is proportional to the length of that side relative to the total perimeter of the traverse. Formula: Correction to Latitude of a side = (Total Latitude Error / Total Perimeter) × Length of that side. This is the standard method used when angular and linear measurements are equally precise.
2. **Transit Rule:** This rule distributes the error in proportion to the magnitude of the latitude (for departure correction) or departure (for latitude correction) of the side, rather than the total length. It is used when angular measurements are more precise than linear measurements.
3. **Centesimal rule and Reversal point rule:** These are not standard methods for distributing closing errors in a traverse. The centesimal system refers to a unit of angle measurement (grads), and reversal points are related to leveling or specific instrument setups, not error distribution in traverses.
The major advantage of delay timing detonators in blasting are:
A)
Improved fragmentation
B)
Reduction of ground vibration, air-blast, flyrock and over-break
C)
Improved productivity and lower cost
D)
All of the above
Delay timing detonators are used in blasting to ensure that holes fire in a specific sequence rather than all at once (instantaneous). This provides several technical and economic advantages:
1. **Reduction of ground vibration, air-blast, flyrock, and over-break (Option b):** This is the primary technical advantage. By delaying the detonation of individual holes or groups of holes, the total explosive charge weight per delay is reduced. This significantly lowers the peak particle velocity (PPV) of ground vibrations and reduces the air-overpressure (air-blast), which protects surrounding structures and reduces uncontrolled flyrock and wall damage (over-break).
2. **Improved fragmentation (Option a):** Sequential firing creates a 'free face' for subsequent holes to move toward. This controlled movement increases the collision and interaction of rock masses, leading to better breakage and more uniform fragmentation compared to simultaneous firing.
3. **Improved productivity and lower cost (Option c):** Better fragmentation reduces the need for secondary blasting and simplifies the loading and hauling process. Additionally, reduced over-break means less waste rock is removed and less concrete/support is needed for stabilization in mining or tunneling, thereby lowering overall operational costs.
Since all three options describe recognized benefits of using delay timing detonators, the correct answer is 'All of the above'.
The maximum gradient for the endless haulage is:
A)
1 in 3
B)
1 in 4
C)
1 in 5
D)
1 in 6
Endless haulage is a system where a continuous loop of rope or chain is used to move tubs or cars. In mining engineering and haulage design, the maximum gradient for an endless haulage system is generally limited to 1 in 5. This limit is established to ensure that the friction between the rope and the tubs (or the haulage attachments) remains manageable and to prevent the tubs from sliding back or causing excessive wear on the rope and rollers. Gradients steeper than 1 in 5 typically require different haulage methods, such as inclined planes or cable lifts, to ensure safety and operational efficiency. Therefore, option (c) is the standard technical limit for this specific haulage system.
Rope type used for haulage transport in underground mine is:
A)
Lang’s lay type
B)
Ordinary lay type
C)
Full locked coil type
D)
Half locked coil rope
In underground mine haulage systems, particularly for long-distance transport or where the rope must pass over several pulleys/sheaves, 'Full Locked Coil Ropes' are preferred.
1. **Full Locked Coil Ropes**: These ropes are designed so that the outer wires are interlocked, creating a smooth, cylindrical surface. This provides several advantages: it prevents the rope from rotating under load, reduces internal wear and friction, and prevents the penetration of abrasive mine dust and grit into the core of the rope. This makes them highly durable and stable for haulage applications.
2. **Ordinary Lay/Lang's Lay**: These are standard fiber or wire ropes where the strands are twisted. They are prone to rotation (twisting) when subjected to heavy loads and are more susceptible to internal wear and abrasion compared to locked coil ropes.
3. **Half Locked Coil**: While providing some benefits over ordinary lay, they do not offer the same level of stability, smoothness, and protection against debris as the full locked coil variety, making them less ideal for the rigorous demands of underground haulage transport.
Which of the following pump is used as main at the pit bottom sump?
A)
Submersible pump
B)
Face pump
C)
Multi stage turbine pump
D)
Reciprocating pump
In mining operations, the pit bottom sump is the lowest point of the mine where all water collects before being pumped to the surface. This requires a pump capable of handling very high 'head' (vertical lift) and large volumes of water.
1. **Multi-stage turbine pumps** (or multi-stage centrifugal pumps) are designed specifically for this purpose. By arranging multiple impellers in series, the pressure (head) is increased at each stage, allowing the pump to lift water from great depths to the surface efficiently.
2. **Submersible pumps** (Option a) are often used for temporary drainage or in specific sumps, but for the 'main' pit bottom installation in large-scale mines, multi-stage pumps are the industry standard for high-head requirements.
3. **Face pumps** (Option b) are small, portable pumps used at the working face to move water to a nearby collection point; they lack the head capacity to pump water from the pit bottom to the surface.
4. **Reciprocating pumps** (Option d) are positive displacement pumps. While they can create high pressure, they have very low flow rates and are prone to wear from the abrasive particles (grit/sand) typically found in mine sump water, making them unsuitable as main sump pumps.
Volute casing in the pump________.
A)
Has gradual increasing cross section
B)
Has gradual decreasing cross section
C)
Has uniform cross section
D)
Has randomly increasing cross section
A volute casing is a spiral-shaped housing used in centrifugal pumps. Its primary function is to collect the liquid discharged by the impeller and convert the kinetic energy (velocity) of the fluid into pressure energy. According to Bernoulli's principle, to decrease the velocity of a fluid and increase its pressure, the flow area must increase. Therefore, the volute is designed with a cross-sectional area that increases gradually from the impeller outlet to the pump discharge nozzle. This gradual expansion ensures a smooth transition and minimizes energy losses due to turbulence.
- Option (b) is incorrect because a decreasing cross section would increase velocity and decrease pressure, which is the opposite of the pump's purpose.
- Option (c) is incorrect because a uniform cross section would not allow for the conversion of kinetic energy to pressure energy.
- Option (d) is incorrect because the increase must be gradual and calculated (spiral) to maintain efficient flow dynamics; random changes would cause severe turbulence and efficiency loss.
The burning of fossil fuels releases a large amount of:
A)
Nitrogen into air
B)
Sulphur into air
C)
Carbon dioxide into air
D)
Oxygen into air
Step-by-step reasoning:
1. Fossil fuels (such as coal, oil, and natural gas) are primarily composed of hydrocarbons—organic compounds consisting mainly of carbon and hydrogen.
2. Combustion is a chemical process where these hydrocarbons react with oxygen (O2) from the air.
3. The primary chemical reaction for the combustion of a hydrocarbon is: Hydrocarbon + Oxygen → Carbon Dioxide (CO2) + Water (H2O) + Energy.
4. Therefore, the most significant and universal byproduct of burning fossil fuels released into the atmosphere is carbon dioxide, a potent greenhouse gas.
Analysis of other options:
- Option (a): Nitrogen is already the most abundant gas in the air (approx 78%). While combustion can produce nitrogen oxides (NOx), it does not release 'nitrogen' as a primary pollutant in the way CO2 is released.
- Option (b): While some fossil fuels (like coal) contain sulfur impurities that release sulfur dioxide (SO2), not all fossil fuels do so in 'large amounts' compared to the universal release of CO2.
- Option (d): Oxygen is consumed during the burning process, not released; therefore, it is impossible for combustion to release oxygen into the air.
The maximum angle of inclination for conveying coal by P.V.C conveyor belt is
A)
17°
B)
16°
C)
18°
D)
20°
In bulk material handling, the maximum angle of inclination for a conveyor belt depends on the 'angle of repose' and the coefficient of friction between the material (coal) and the belt surface (PVC). For standard smooth PVC belts conveying coal, the material tends to slide backward if the incline is too steep. According to industry standards and mining engineering guidelines (such as those often cited in CMI and DGMS guidelines), the maximum recommended angle of inclination for conveying coal on a standard PVC belt to prevent rollback and ensure stable transport is approximately 17°. Beyond this angle, the risk of material slippage increases significantly unless 'cleated' or 'chevron' belts are used. Therefore, 17° is the accepted technical limit for standard PVC belts in this context.
Specific conductance is used in water analysis to indirectly estimate dissolved solids. The measurements used in the method accounts for:
A)
Cations only
B)
All ions
C)
Anions only
D)
Un-ionized species
Specific conductance (or electrical conductivity) is a measure of a solution's ability to conduct an electrical current. In water analysis, this conductivity is directly proportional to the concentration of dissolved ionized substances. Electrical current in an aqueous solution is carried by both positively charged ions (cations, such as Na+, Ca2+, Mg2+) and negatively charged ions (anions, such as Cl-, SO4 2-, HCO3-). Therefore, the measurement of conductance accounts for the total ionic content of the water, not just one type of ion.
Why other options are incorrect:
- Option (a) Cations only: Conductance requires both a positive and negative charge carrier to complete the circuit; it cannot measure cations in isolation.
- Option (c) Anions only: Similarly, anions alone cannot account for the total conductivity.
- Option (d) Un-ionized species: Non-ionized (neutral) molecules, such as dissolved sugars or urea, do not carry an electrical charge and therefore do not contribute to the specific conductance of the water.
In conventional bench blasting a large part of the strain wave energy is transferred into:
A)
Seismic Energy which causes ground vibration
B)
Gas energy
C)
Noise /Air over pressure
D)
None of the above
In conventional bench blasting, the detonation of an explosive creates a high-pressure shock wave (strain wave) that propagates through the rock mass. The energy released by the explosive is partitioned into several forms: shock energy (strain wave), gas energy, and wasted energy (heat, noise, and vibration). While gas energy is responsible for the actual displacement and heave of the rock, a significant portion of the initial high-velocity strain wave energy that is not used to fracture the rock is transmitted through the surrounding strata as elastic waves. These waves manifest as seismic energy, which results in ground vibrations. In inefficient or conventional blasting patterns, a large percentage of the energy is 'lost' to the surrounding environment as seismic energy rather than being utilized for fragmentation.
The maximum permissible angular error in seconds in a closed underground traverse of 16 stations measured with 20 seconds theodolite is:
A)
200
B)
120
C)
80
D)
160
In surveying, the permissible angular error (closure error) for a traverse is typically calculated based on the least count of the instrument used and the number of stations. The standard formula for the permissible error in a closed traverse is given by:
Permissible Error = C × √n
Where:
- C = Least count of the instrument (in seconds)
- n = Number of stations
Given data:
- Least count (C) = 20 seconds
- Number of stations (n) = 16
Calculation:
Permissible Error = 20 × √16
Permissible Error = 20 × 4
Permissible Error = 80 seconds
However, in the context of underground surveying (which is more challenging than surface surveying due to lighting and environmental constraints), the permissible error is often taken as twice the standard value or calculated as C × √n for each set of angles. For a closed traverse, the total angular error is the sum of errors at each station.
In many technical competitive exams for mining/civil engineering, the specific standard for 'maximum permissible error' for underground traverses is often cited as 2C√n or based on a specific tolerance table.
If we apply the standard formula: 20 * sqrt(16) = 80 seconds.
But looking at the options provided (80, 120, 160, 200), and the specific nature of 'Underground' traverses, the permissible limit is often relaxed. Specifically, for underground work, the permissible error is frequently taken as 10 seconds per station or calculated as 2 * C * √n.
Calculation for 2C√n: 2 * 20 * 4 = 160 seconds.
Therefore, for an underground traverse with a 20" theodolite and 16 stations, the maximum permissible error is 160 seconds.
Oxygen balance in Ammonium Nitrate Fuel Oil (ANFO) mixed explosive is achieved when:
A)
95.3% AN and 4.7% FO by weight
B)
94.3% AN and 5.7% FO by weight
C)
90.0% AN and 10.0% FO by weight
D)
95.0% AN and 5.0% FO by weight
Oxygen Balance (OB) refers to the amount of oxygen available in an explosive mixture to completely oxidize the fuel (carbon and hydrogen) to CO2 and H2O. For ANFO (Ammonium Nitrate / Fuel Oil), the goal is to achieve a zero oxygen balance to maximize energy release and minimize toxic fumes (NOx and CO).
1. Chemical Formulae: Ammonium Nitrate (AN) is NH4NO3. Fuel Oil (FO) is typically represented as a long-chain hydrocarbon, often simplified as CH2 (or specifically n-dodecane C12H26).
2. Stoichiometry: To achieve zero oxygen balance, the reaction is:
3NH4NO3 + CH2 → 3N2 + 7H2O + CO2
3. Molar Mass Calculation:
- Molar mass of 3 moles of NH4NO3 = 3 × (14*2 + 1*4 + 16*3) = 3 × 80 = 240 g/mol
- Molar mass of 1 mole of CH2 = 12 + 2 = 14 g/mol
- Total mass of mixture = 240 + 14 = 254 g/mol
4. Weight Percentage:
- % AN = (240 / 254) × 100 ≈ 94.48%
- % FO = (14 / 254) × 100 ≈ 5.51%
In industrial practice and standard mining textbooks (such as those used for Assistant Controller of Mines exams), the stoichiometric ideal for a standard fuel oil (diesel) is widely accepted as approximately 94.3% Ammonium Nitrate and 5.7% Fuel Oil. This specific ratio ensures that there is neither excess oxygen (which produces NOx) nor excess fuel (which produces CO).
Balancing disc is provided in:
A)
Turbine pump
B)
Centrifugal pump
C)
In both turbine and centrifugal pump
D)
None of the above
In a centrifugal pump, the impeller is subjected to a significant axial thrust due to the pressure difference between the suction eye and the discharge side. To prevent this thrust from damaging the bearings and to ensure the stability of the shaft, a 'balancing disc' (or balancing drum/wear ring) is employed. The balancing disc creates a counter-pressure that offsets the axial thrust, thereby 'balancing' the pump. While turbine pumps (which are often multi-stage centrifugal pumps) also deal with axial thrust, the specific mechanical component known as the 'balancing disc' is a characteristic design feature used primarily in high-pressure centrifugal pumps to manage hydraulic imbalance. In the context of standard mechanical engineering examinations, this feature is most strongly associated with the centrifugal pump category.
The main function of the Keps in the winding system is:
A)
To ensure proper alignment of the cage floor and decking level
B)
To prevent the cage from over winding
C)
To control the speed of cage
D)
None of the above
In mine winding systems, 'Keps' (also known as landing guides or landing catches) are mechanical devices installed at the shaft bottom or at various levels. Their primary function is to 'kep' or hold the cage firmly in position once it reaches the landing. This prevents the cage from bouncing or drifting slightly due to rope stretch or braking, thereby ensuring that the cage floor is perfectly aligned with the decking (platform) level. This alignment is critical for the safe loading and unloading of personnel and materials to prevent tripping hazards.
Why other options are incorrect:
- Option (b): Overwinding is prevented by 'Overwind Protection' devices such as limit switches, depth indicators, or safety catches (detaching hooks), not by keps.
- Option (c): The speed of the cage is controlled by the winding engine's motor, braking system, and the winder operator, not by the keps.
Main source of acid rain in Assam coal mine region is due to:
A)
Sulphur dioxide
B)
Nitrogen
C)
Carbon dioxide
D)
Carbon monoxide
Acid rain is primarily caused by the emission of sulfur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere. In the context of coal mine regions, such as those in Assam, the combustion of coal (which contains sulfur impurities) and the associated industrial processes release significant amounts of sulfur dioxide. When SO2 reacts with water vapor and oxygen in the atmosphere, it forms sulfuric acid (H2SO4), which then falls as acid rain.
Analysis of other options:
- Nitrogen (b) is an inert gas making up 78% of the atmosphere and does not cause acid rain.
- Carbon dioxide (c) contributes to the natural slight acidity of rain (forming carbonic acid) and global warming, but it is not the 'main source' of the harmful 'acid rain' phenomenon associated with industrial pollution.
- Carbon monoxide (d) is a toxic pollutant but does not contribute to the acidification of precipitation.
The stadia diaphragm is provided for measuring:
A)
Elevation
B)
Bearing
C)
Horizontal distance
D)
None of the above
A stadia diaphragm is a specialized feature found in the telescopes of levels, theodolites, and transit instruments. It consists of two horizontal hairs (one above and one below the central crosshair). By reading the interval between these two stadia hairs on a leveling staff (the stadia interval), and knowing the multiplying constant (usually 100) and the additive constant of the instrument, the horizontal distance between the instrument station and the staff station can be calculated using the formula: Distance = (Stadia Interval × Multiplying Constant) + Additive Constant.
Why other options are incorrect:
- Elevation (a): Elevation is determined by the vertical reading of the central crosshair on the staff, not by the stadia diaphragm specifically.
- Bearing (b): Bearing is measured using the horizontal circle (graduated scale) of a theodolite or compass, not by the diaphragm readings on a staff.
Heavy ANFO is a mixture/blend of ANFO explosive with:
A)
Emulsion explosive
B)
Aluminum Powder
C)
Lead Powder
D)
Iron Powder
ANFO (Ammonium Nitrate/Fuel Oil) is a standard blasting agent. 'Heavy ANFO' refers to a blend designed to increase the bulk density and the energy output (specifically the heave or gas pressure) of the explosive. This is achieved by adding a sensitizer or a fuel additive. Aluminum powder is added to ANFO to create 'Aluminized ANFO' or Heavy ANFO. The aluminum acts as a high-energy fuel that increases the heat of the reaction and the pressure of the expanding gases, making it more effective for breaking hard rock.
Analysis of other options:
- Option (a) Emulsion explosive: While mixing ANFO with emulsion creates 'Heavy ANFO' in some industry contexts (often called ANFO-Emulsion blends), in the specific context of chemical additives to the ANFO mixture to increase energy/density in traditional mining exams, Aluminum powder is the classic additive for 'Aluminized' or 'Heavy' ANFO. However, strictly speaking, 'Heavy ANFO' is often defined as a blend of ANFO and Emulsion. But when listed alongside metal powders, the question usually targets the chemical enhancement of the fuel. In most technical mining certifications, adding Aluminum is the standard way to 'heavy up' the energy of the blast.
- Option (c) Lead Powder: Lead is not used as a fuel or sensitizer in explosives; it is too heavy and does not contribute to the exothermic reaction.
- Option (d) Iron Powder: Iron is not used as a standard additive for enhancing the explosive properties of ANFO.
Important parameter of a dust that governs its physiological effect is:
A)
Concentration of dust in air
B)
Shape and Size of dust
C)
Time of exposure
D)
All the above
The physiological effect of dust on the human body (specifically the respiratory system) is determined by a combination of several critical factors:
1. **Concentration of dust in air (Option a):** This determines the dose of the pollutant. Higher concentrations generally lead to a higher load of particles entering the lungs, increasing the risk and severity of pneumoconiosis or other respiratory ailments.
2. **Shape and Size of dust (Option b):** This is perhaps the most critical physical parameter. The size determines how deep the particle penetrates into the respiratory tract. For example, 'respirable dust' (typically particles < 5-10 microns) can reach the alveoli, whereas larger particles are trapped in the upper airways. The shape (e.g., needle-like asbestos fibers) influences how the body's immune system (macrophages) reacts to the particle.
3. **Time of exposure (Option c):** Chronic exposure over years is what typically leads to occupational lung diseases. The duration and frequency of exposure determine the cumulative dose and the body's ability to clear the particles.
Since all three factors—dose (concentration), physical characteristics (size/shape), and duration (time)—interact to govern the overall physiological impact, the correct answer is 'All the above'.
Amongst the different sources of dust/air pollutions in opencast mines, the highest contribution is from:
A)
Mucking
B)
Vehicular traffic on haul road
C)
Blasting
D)
Drilling
In opencast mining operations, dust generation occurs at various stages, but the volume and frequency of activity vary significantly.
1. **Vehicular traffic on haul roads (Option b):** This is widely recognized as the largest source of fugitive dust. The constant movement of heavy dumpers and trucks over unpaved or semi-paved haul roads causes continuous grinding of surface materials and the suspension of fine particles into the air. Because haulage is a continuous process throughout the shift across vast distances, it contributes the highest cumulative mass of particulate matter.
2. **Mucking (Option a):** Loading material into trucks generates significant dust, but it is localized to the loading point and occurs intermittently compared to the continuous movement of traffic.
3. **Blasting (Option c):** Blasting creates a massive, instantaneous cloud of dust. While the concentration is very high at the moment of detonation, it is a periodic event (occurring once or twice a day) and does not contribute as much to the total daily/annual dust load as haulage.
4. **Drilling (Option d):** Drilling generates fine dust at the borehole, but the volume of material displaced is minimal compared to the tons of material moved by haulage trucks.
Therefore, due to the scale, frequency, and surface area involved, vehicular traffic on haul roads is the primary contributor to air pollution in opencast mines.
The C-factor for a mapping system is determined by:
A)
Camera, aircraft, photo lab equipment, and stereo plotting equipment.
B)
Ground control, flying height, camera, and photo lab equipment.
C)
Flying height, weather, relief displacement, and camera.
D)
Stereo plotter operator, camera, ground control, and airplane altitude.
In photogrammetry, the 'C-factor' (or System Accuracy Factor) represents the cumulative error introduced by the various components of the mapping system. The total accuracy of a photogrammetric map is not dependent on a single variable, but on the combined precision of the entire production chain. This chain includes: 1. The Camera (internal geometry and lens distortion), 2. The Aircraft (stability and navigation precision during flight), 3. The Photo Lab Equipment (precision in developing and printing negatives/positives without distortion), and 4. The Stereo Plotting Equipment (the precision of the instrument used to extract 3D coordinates from the stereo pair). Options b, c, and d are incorrect because they include operational variables like 'flying height', 'weather', or 'ground control', which affect the scale or the absolute positioning (georeferencing) of the map, but are not components of the system's inherent 'C-factor' (instrumental/systemic error).