What is the main purpose of special mining methods like slicing and blasting gallery?
B
To handle difficult geological conditions and improve recovery
C
To increase manual labor
Analysis & Theory
Special methods help extract coal from seams with unique challenges such as thickness, depth, or gassiness.
Inclined slicing is primarily suitable for:
B
Highly inclined thick seams
Analysis & Theory
Inclined slicing is used to extract coal from steeply dipping thick seams.
Horizontal slicing involves:
B
Extracting coal in horizontal layers from bottom to top
Analysis & Theory
Horizontal slicing extracts coal in horizontal slices, usually ascending from bottom to top.
Blasting Gallery method is mainly applicable to:
B
Highly gassy and thick seams
Analysis & Theory
The Blasting Gallery method is designed for thick seams with high gassiness where mechanized cutting is difficult.
Which mining method uses controlled blasting for extraction in thick seams?
B
Blasting gallery method
Analysis & Theory
Blasting Gallery involves large-scale controlled blasting to extract coal from thick seams.
Horizon mining is used to:
A
Increase roof collapses
B
Work multiple thick seams at different levels
Analysis & Theory
Horizon mining divides thick seams into horizons or levels for better control and mechanization.
Hydraulic mining extracts coal using:
B
Water jets under high pressure
Analysis & Theory
Hydraulic mining uses high-pressure water jets to break and wash coal from the seam.
Which of the following is a key advantage of hydraulic mining?
C
Safe and suitable for weak roofs
Analysis & Theory
Hydraulic mining is ideal in weak roof conditions as it avoids roof collapse hazards.
Gasification of coal is a process of:
B
Converting coal into gaseous fuel underground
Analysis & Theory
Underground Coal Gasification (UCG) converts coal into gas in situ by controlled combustion.
Underground Coal Gasification is best suited for:
B
Deep, unmineable coal seams
Analysis & Theory
UCG is ideal for deep seams that are not economically or technically mineable.
Which of the following is **not** required in UCG?
A
Injection of air/oxygen
D
Collection of gas via production well
Analysis & Theory
UCG does not involve slurry pumping, which is used in hydraulic mining.
One of the by-products of coal gasification is:
Analysis & Theory
Gasification produces syngas—a mixture of CO, H₂, CH₄, etc.
A demerit of blasting gallery mining is:
B
Need for advanced safety measures due to gassiness
D
Zero environmental impact
Analysis & Theory
Due to large-scale blasting in gassy seams, strict safety precautions are needed.
Inclined slicing is commonly practiced in which country?
Analysis & Theory
Inclined slicing is widely practiced in Indian coalfields like Jharia and Raniganj.
Hydraulic mining is best applicable in:
A
Dry and hard coal seams
C
Soft coal seams with poor roof
Analysis & Theory
Soft seams and poor roofs are ideal for hydraulic mining where mechanical methods are unsafe.
In horizon mining, the coal seam is divided:
B
Horizontally into multiple working levels
Analysis & Theory
Horizon mining creates levels or horizons within a thick seam for efficient extraction.
What is the primary energy source used in UCG?
C
Combustion of part of the coal
Analysis & Theory
UCG initiates combustion in-situ to convert part of the coal into usable gas.
Which method is designed to overcome limitations of very thick seams?
Analysis & Theory
Inclined slicing divides thick seams to allow safer and more controlled extraction.
Blasting gallery panels are usually:
C
Large in size and pre-developed
Analysis & Theory
Blasting Gallery panels are large and extensively developed before blasting begins.
Which equipment is essential in hydraulic mining?
C
High-pressure water jet
Analysis & Theory
High-pressure water jets are used to break coal in hydraulic mining.
A major concern in underground gasification is:
B
Surface stability and gas leakage
Analysis & Theory
Gas leakage and land subsidence are major risks in UCG.
In horizon mining, haulage is carried out at:
Analysis & Theory
Horizon mining consolidates transport at a central level for efficiency.
Blasting gallery method requires which special control?
C
Gas monitoring and ventilation
Analysis & Theory
Due to explosive usage in gassy seams, strict gas and ventilation control is needed.
Hydraulic mining is not suitable where:
C
Water is scarce or restricted
Analysis & Theory
Hydraulic mining requires a significant water supply.
The gas from UCG can be used for:
B
Power generation and chemical synthesis
Analysis & Theory
Gasified coal products are used for power and synthesis of fuels and chemicals.
What is a benefit of horizon mining?
C
Improved transport and ventilation
Analysis & Theory
Horizon mining enables better mechanization, transport, and ventilation.
Which method reduces air leakage in thick seam mining?
B
Inclined slicing without stowing
C
Stowing in blasting gallery panels
D
Top slicing with caving
Analysis & Theory
Stowing seals the goaf and helps reduce air leakage and fire risk.
UCG is beneficial for:
A
Thick seams at shallow depth
B
Unmineable coal at deep depth
Analysis & Theory
UCG enables use of coal seams that are uneconomical for conventional mining.
Blasting gallery mining ensures extraction without:
Analysis & Theory
Large blasts remove the need for manual cutting.
Which is the **most suitable** special method for steep and thick seams with good roof?
Analysis & Theory
Inclined slicing works well for steep seams with good roof control.