Classes of Coal and Usage

Question 1

What is the primary origin of coal?

Answer 1

Altered remains of lush vegetation.

Question 2

What geological stage involves initial peat formation?

Answer 2

Microbial Stage.

Question 3

Which stage of coal formation is characterized by the conversion of peat to coal?

Answer 3

Biochemical Stage.

Question 4

What is the term for the process that transforms peat into higher ranks of coal?

Answer 4

Coalification

Question 5

What are the two main factors affecting coalification?

Answer 5

Heat and pressure.

Question 6

Define “coal rank.”

Answer 6

The degree of coalification.

Question 7

What does “coal grade” refer to?

Answer 7

The quantity of impurities in coal.

Question 8

Which type of coal has the highest heating value?

Answer 8

Anthracite.

Question 9

What is the maximum volatile matter percentage in subbituminous coal?

Answer 9

40%.

Question 10

Identify one characteristic of lignite coal.

Answer 10

Light brown to black color.

Question 11

Which classification system is primarily used in the United States for coal?

Answer 11

ASTM classification system.

Question 12

What is the primary use of coking coal?

Answer 12

Steel production.

Question 13

What does Hilts’ rule state regarding volatile matter content?

Answer 13

Volatile matter decreases with increasing depth.

Question 14

What are macerals in coal?

Answer 14

Microscopic constituents derived from plant material.

Question 15

Which maceral constitutes 80% or more of U.S. coal?

Answer 15

Vitrinite

Question 16

Identify one property that distinguishes inertinite from other macerals.

Answer 16

Low volatile matter content.

Question 17

What does reflectance measure in coal petrography?

Answer 17

The proportion of light reflected from a polished surface, indicating rank.

Question 18

What are lithotypes in relation to coal?

Answer 18

Megascopic constituents visible to the naked eye.

Question 19

Name one lithotype that appears bright and glassy.

Answer 19

Vitrain

Question 20

Which lithotype is characterized by a dull, greasy luster and granular texture?

Answer 20

Durain

Question 21

Identify a common impurity found in U.S. coals classified as silicates.

Answer 21

Kaolinite

Question 22

What type of impurity is described as being intimately mixed with coal?

Answer 22

Inherent impurities.

Question 23

Which mineral group includes sulfides commonly found in coals?

Answer 23

Sulfide minerals.

Question 24

Name one method used to analyze macerals in coal samples.

Answer 24

Microscopy (transmitted or reflected light).

Question 25

What is the significance of the Gray-King test in coal classification?

Answer 25

It determines coking properties based on heating behavior.

Question 26

Identify one environmental impact associated with coal mining operations.

Answer 26

Land degradation or water pollution.

Question 27

In which country was an international coal classification system developed after World War II?

Answer 27

United Nations (UN).

Question 28

What does “caking property” refer to in coals?

Answer 28

The ability of coal to form a coherent mass when heated.

Question 29

Which maceral group is primarily responsible for coking properties in coals?

Answer 29

Vitrinite

Question 30

What is fusinite characterized by in terms of reflectance and carbon content?

Answer 30

Very bright under reflected light; highest carbon content among macerals.

Question 31

Define “volatile matter” in the context of coal analysis.

Answer 31

The portion of coal that can be released as gas or vapor when heated.

Question 32

Which type of mining method typically results in higher environmental impact, surface or underground mining?

Answer 32

Surface mining.

Question 33

Name one factor that influences the heating value of different types of coal.

Answer 33

Moisture content.

Question 34

What is the primary chemical component found in all coals?

Answer 34

Carbon.

Question 35

Identify one health risk associated with exposure to coal dust during mining operations.

Answer 35

Respiratory diseases (e.g., pneumoconiosis).

Question 36

Which type of coal has less than 8% volatile matter?

Answer 36

Anthracite.

Question 37

Name one characteristic feature of clarain lithotype in coals.

Answer 37

Bright to semi-bright laminated bands with silky luster.

Question 38

What does ASTM stand for in relation to coal classification standards?

Answer 38

American Society for Testing and Materials.

Question 39

Which digit in the UN international classification system indicates volatile matter content?

Answer 39

First digit.

Question 40

Identify a mineral commonly associated with ash content in coals from the carbonate group.

Answer 40

Calcite (CaCO3).

Question 41

In terms of reflectance, what indicates higher rank coals?

Answer 41

Increased reflectance values correlate with higher rank coals.

Question 42

What does “segregated impurity” mean regarding its association with coal?

Answer 42

Discrete particles that exist separately from the coal matrix.

Question 43

Name one technological advancement that has improved efficiency in coal utilization processes recently.

Answer 43

Carbon capture and storage (CCS).

Question 44

Which country is known for its lignite reserves and extensive lignite mining operations?

Answer 44

Germany.

Question 45

Define “coal liquefaction” and its primary purpose in energy production

Answer 45

A process that converts solid coal into liquid hydrocarbons for fuel production.