Ash Content: Ash content represents the inorganic residue left after coal combustion. Lower ash content is desirable as high ash content can reduce combustion efficiency and increase maintenance requirements.

Sulfur Content: High sulfur content in coal leads to the production of sulfur dioxide during combustion, which contributes to air pollution and acid rain. Lower sulfur content is generally preferred.

Volatile Matter: Volatile matter refers to the components of coal that vaporize when heated. It affects the ease of ignition and combustion characteristics of coal.

Petrographic Analysis: This analysis involves the microscopic examination of coal samples to determine their composition, rank, and structure. It helps classify coal into different types (such as anthracite, bituminous, or lignite) and provides insights into its formation and properties.

Grindability: Grindability measures the ease with which coal can be ground into a fine powder. It is an important factor for coal used in pulverized coal combustion systems.

These diagnostic methods, along with other specific parameters depending on the intended use of the coal, help assess its quality and suitability for various applications such as power generation, industrial processes, and metallurgical processes