Introduction To Mining Engineering — Part 1 MCQs with Explanations

In a Poisson distribution, the occurrence of events (in this case, the occurrence of minerals in a rock) is randomly distributed over a given interval. This distribution is commonly used to model rare events and is often used in mining engineering when studying the distribution of minerals in rocks. Therefore, the correct option is D.

Shaley Roof: A shaley roof refers to a roof in underground mining that consists of shale, a sedimentary rock composed of fine particles. Shale is known for its layered structure, making it relatively weak and susceptible to damage under specific conditions. Correct Answer: Option C: It has great affinity to absorb moisture and get departed from immediate roof Reason: Shale is a type of sedimentary rock that tends to absorb moisture easily. When a shaley roof is not supported by coal or other stronger materials, it becomes highly unstable because: The shale absorbs moisture from the surrounding environment. This absorption leads to the swelling of the shale, causing it to lose its structural integrity. As a result, the shale starts to separate (or depart) from the immediate roof surface, increasing the risk of roof falls and making it challenging to control during mining operations. Why Leaving Coal Helps: Leaving a layer of coal with the shale provides support and reduces direct exposure to moisture. Coal acts as a protective layer, ensuring that the shale does not come into direct contact with environmental factors that might accelerate its degradation. Other Options: Option A: It is weak in nature While shale is generally weaker compared to other rocks, the main challenge in controlling a shaley roof comes from its tendency to absorb moisture and separate, as stated in Option C. Option B: It has weathering effect Although weathering might affect shale over time, it is not the primary reason for difficulty in controlling a shaley roof in an underground mining setting. Option D: It reacts with coaly surface There is no significant chemical reaction between shale and the coal surface that would contribute to the instability of the roof. Thus, the correct answer is Option C because moisture absorption and subsequent separation from the immediate roof are the primary challenges with a shaley roof in mining engineering.

For shafts exceeding 130 meters in depth, regulations typically require significant overhead protection when lowering or raising persons using equipment like buckets. This is to ensure the safety of workers by preventing injuries from falling debris or objects. The depth of 130 meters is a standard threshold in many mining safety guidelines, beyond which additional precautions, such as overhead covers, become mandatory. Why other options are incorrect: - Option B: 190m : This depth exceeds the standard threshold of 130 meters and is not the correct answer. - Option C: 270m : This depth is also beyond the standard threshold and is not relevant to the question. - Option D: 500m : This depth is significantly higher than the standard threshold and is not applicable in this context. Thus, the correct answer is Option A: 130m , as it aligns with standard mining safety regulations for overhead protection in deep shafts.

Definition: In mining engineering, specific terms such as Access , Haulage , and Mineralisation are crucial for understanding mining operations: Access: Refers to the means by which miners reach an underground ore body, such as through shafts, declines, or adits. Haulage: Involves the transportation of mined material from underground to the surface, which can be done using track systems, trackless vehicles, or hoisting equipment. Mineralisation: Describes the concentration and distribution of valuable minerals in an ore body, which varies based on depth and location. Explanation: The correct answer is Option B: P-3-b, Q-2-a, R-1-c . Matching Details: P (Shaft): Shafts are vertical access points often associated with hoisting (3) and are typically used for accessing deep-seated (b) mineral deposits. Q (Decline): Declines are inclined tunnels commonly used for trackless haulage (2) and are ideal for moderate-depth (a) mineral deposits. R (Adit): Adits are horizontal or near-horizontal tunnels used in areas like hillocks (c) and are associated with track haulage (1). Why other options are incorrect: Option A: Incorrect pairing of features and purposes. Option C: Misalignment of haulage methods and mineralisation depths. Option D: Does not follow the logical association of methods with corresponding mining conditions. Thus, the correct matching is P-3-b, Q-2-a, R-1-c , making Option B the correct answer.

Given data: Number of holes (n) = 9 Hole length (L) = 8m Hole diameter (D) = 200mm = 0.2m Spacing (S) = 6m Burden (B) = 5m Subgrade drilling length = 1m Density of in-situ rock (ρ rock ) = 2.43 t/m 3 Explosive density (ρ explosive ) = 0.9 t/m 3 Stemming length = 2m First, calculate the volume of a single hole: Volume of hole (V hole ) = π/4 * D 2 * L Volume of hole (V hole ) = π/4 * (0.2m) 2 * 8m Volume of hole (V hole ) = 0.0251 m 3 Next, calculate the total blasted volume (V total ): Total blasted volume (V total ) = n * V hole Total blasted volume (V total ) = 9 * 0.0251 m 3 Total blasted volume (V total ) = 0.2259 m 3 Now, calculate the burden-to-spacing ratio (B/S): Burden-to-spacing ratio (B/S) = B / S Burden-to-spacing ratio (B/S) = 5m / 6m Burden-to-spacing ratio (B/S) = 0.833 Calculate the effective volume (V eff ): Effective volume (V eff ) = V total * (1 - B/S) Effective volume (V eff ) = 0.2259 m 3 * (1 - 0.833) Effective volume (V eff ) = 0.0376 m 3 Calculate the total volume of explosive (V explosive ): Total volume of explosive (V explosive ) = V eff + n * π/4 * D 2 * subgrade drilling length Total volume of explosive (V explosive ) = 0.0376 m 3 + 9 * π/4 * (0.2m) 2 * 1m Total volume of explosive (V explosive ) = 0.1935 m 3 Calculate the total weight of explosive (W explosive ): Total weight of explosive (W explosive ) = V explosive * ρ explosive Total weight of explosive (W explosive ) = 0.1935 m 3 * 0.9 t/m 3 Total weight of explosive (W explosive ) = 0.1742 t Calculate the total weight of rock (W rock ): Total weight of rock (W rock ) = V total * ρ rock Total weight of rock (W rock ) = 0.2259 m 3 * 2.43 t/m 3 Total weight of rock (W rock ) = 0.5489 t Finally, calculate the powder factor (P): Powder factor (P) = W explosive / W rock Powder factor (P) = 0.1742 t / 0.5489 t Powder factor (P) = 0.3175 The correct powder factor rounded off to two decimal places is approximately 0.32 t/kg, which does not match option D: 3.01. The provided options and calculations still seem to be inconsistent. Please verify the data and calculations to ensure accurate results.

In standard diamond rod specifications: AW corresponds to an outer diameter of 34.9 mm (P) BW corresponds to an outer diameter of 44.4 mm (Q) EW corresponds to an outer diameter of 54.0 mm (R) NW corresponds to an outer diameter of 66.7 mm (S) Matching these with the given options: Option C correctly matches: P (AW) with q (34.9 mm) Q (BW) with r (44.4 mm) R (EW) with p (54.0 mm) S (NW) with s (66.7 mm) Therefore, Option C is the correct match for the standard diamond rod specifications.

The correct answer is Option B: NX > BX > AX > EX . Here's why: These codes (NX, BX, AX, EX) refer to standard core sizes used in core drilling during mineral exploration and geotechnical investigations. They represent the diameter of the rock core retrieved from the drill hole. The letters are in a roughly descending order of size. * NX core is the largest of the given options. * BX core is smaller than NX. * AX core is smaller than BX. * EX core is the smallest of the given options. Therefore, the correct order from largest to smallest core size is NX > BX > AX > EX.

5 level heading district is the correct answer to “Which of the following combination of SDL based mining is expected to give best production and productivity of SDL”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

34.5 is the correct answer to “In a mine deploying shovel and dumper, the distance from the crest of the bench to the centre of the dumper including safety berm and clearance is 7.5m, the dumping radius and the cutting radii of the shovel are 15m and 12m respectively. The width of the working bench of the mine in m is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

2.3, 1.8 is the correct answer to “In a room-and-pillar stope, bench blasting is conducted using ANFO having density of 800 kg/m 3 . The specific gravity of rock is 2.5, hole diameter is 100 mm and spacing to burden ratio is 1.3. The charge length of each blast hole is 80% of the hole length. For a desired powder factor of 0.48 kg/tonne, the spacing and burden of the blast pattern in m respectively are”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

1.50 is the correct answer to “In a mine for one shovel six trucks are assigned. The shovel loading time per truck is 5 min, and truck cycle time 20 min. Calculate the match factor.”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

13.55 is the correct answer to “The following data are provided for a surface mine to be excavated by a shovel: Production target: 10000 te/shift Available hours per shift: 6 hrs Shovel loading cycles per hour: 10 6 Bank density of the material mined: 2400 kg/m 3 Swing factor at 120° swing: 0.91 Bucket fill factor : 0.64 Utilization of available time: 83% No of working days in a year : 300 No of shifts per day : 3 The size of bucket of the shovel in m 3 is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Roof bolt is the correct answer to “Which of the following support has maximum linear progress”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

1.0m is the correct answer to “Every ladder way used in a mine shall project above the mouth of at least”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Land area acquisition and rehabilitation is the correct answer to “Which of the following is most difficult in opening up an opencast mine”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

30 is the correct answer to “In-situ ore of 1.5% Cu got diluted with waste rock of value 0.2% Cu. If the resultant extracted ore has 1.2% Cu. What is the percentage of dilution”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Sublevel stoping is the correct answer to “Top slicing is an underhand caving method which is a variation of”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

65 and 100 is the correct answer to “The diameter of holes in mm commonly used for ring drilling by drifters in sublevel stoping is between”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Endless haulage is the correct answer to “Friction Clutch is used for”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Stowing operation is the correct answer to “The process that sends sand water mixture in underground coal depillaring district is known as”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Stope and pillar mining is the correct answer to “Which of the following method of mining is only applicable to non-coal mines”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

100m is the correct answer to “As per CEA 2010, the length of flexible cable used in portable and transportable apparatus shall not be more than”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

18.80 is the correct answer to “A dragline is required to remove 3,00,000 m 3 of rock per month on the bank volume basis. Consider the following data for the dragline operation. Effective working hours per month = 450 Bucket fill factor = 0.8 Cycle time = 65 s Swell factor of the rock = 1.25 The minimum bucket capacity of the dragline in m 3 is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

199.4 is the correct answer to “A shearer is deployed in a mine where the specific energy consumption for cutting coal is 800 kJ/m 3 . The specific gravity of coal is 1.2. If the machine produces 700 te/h, the electrical power consumption in kW of the shearer at 65% motor efficiency is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Safari supports is the correct answer to “In an underground coal mine, a freshly exposed roof can be supported by a temporary support in the form of”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

4.63 is the correct answer to “A bucket wheel excavator with 20 buckets of capacity 0.5 m 3 each, rotates at 5 rev/min. The bucket fill factor is 80%. The excavator loads on to 1200 mm wide belt conveyor. The cross-section area (m 2 ) of the material on the belt is 0.1B 2 , where B is the belt width in m. The minimum speed of the belt in m/s to avoid spillage of material is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

8.18 is the correct answer to “An ore block of length 30m and height 20m having an average width of 1.5m with sharp boundary walls is mined with a minimum mining width of 2m. If the tonnage factors are 3 t/m 3 for ore, 2 t/m 3 for wall rock and average grade of ore is 10%, the diluted grade of ore mined in percent is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

2.26 is the correct answer to “In an overburden bench of an iron ore mine the following data were found: Height = 10m Burden = 4m Spacing = 3m Sub-grade drilling length = 1m Collar stemming length = 3m If the diameter of the explosive column is 150 mm and the specific gravity of explosive and that of rock are 0.9 and 2.4 respectively, the powder factor in te/kg will be”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

All of the above is the correct answer to “Cut & Fill stoping can be done by”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

15 is the correct answer to “A flat coal seam of thickness (t) 3m is excavated and broken roof rock has completely filled the space created due to extraction as shown in the figure. If the bulking factor of roof rock is 1.2. the caving height (H) in m is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

R > S > Q > P is the correct answer to “In the order of the chronological development, the longwall support systems are arranged as P Powered support Q Link bar and friction support R Frame support S Hydraulic support”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Moderate is the correct answer to “Water bearance of Indian coal seam is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

13.5m is the correct answer to “In any working below ground there should be provided at least two shaft or incline which should be away from each other by a minimum distance”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

2.1 is the correct answer to “A vertical ore body having a consistent width of 100 m has been excavated by the open pit method up to a depth of 100 m at a pit slope angle of 45°. The figure shows the cross section of the open pit. If the ore body is further excavated by a depth of 10 m, maintaining the same pit slope angle, the ratio of waste rock to ore is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

25 ms is the correct answer to “The delay interval in short delay detonator is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Flumes is the correct answer to “What is the name of the media through which coal pulp in hydraulic mining is sent from face to pulp sump or coal crusher”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

It has high affinity to moisture & departs from roof easily is the correct answer to “Shale as immediate roof in underground, coal mine is not suitable because”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

Blasting all the holes in slices is the correct answer to “Blasting of stope in VCR method consists of”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

LHD is the correct answer to “Which one of tire following HEMM is a tyre mounted”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.

2.56 is the correct answer to “In an opencast mine shown in the figure below, the coal has a density of 1.4 t/m 3 . Assuming mining operation started from plane XY, the operating stripping ratio under the given conditions in m 3 /t is”. This question is standard in competitive examination syllabi for Introduction To Mining Engineering.