Coal is marked by quality, for using in industrial. Coal subdivided on marks, which flow from the way they lead them self by thermal impact.
Classification in post-soviet countries different than in EU or USA. In this classification usually allocating eight main marks, which, mostly, differentiates by exit of combustible substances, contents of carbon and heat of combustion (kcal/g).
| Mark | Exit of combustible substances | Contents of carbon | Heat of combustion (kcal/g) |
| Lignite | ≈60% | ≈60% | 6000 kcal |
| Long-flame | ≈35% | ≈75% | 5300 kcal |
| Gauze | ≈35% | ≈85% | 7700 kcal |
| Oily | ≈32% | ≈86% | 8000 kcal |
| Coke | <25% | ≈90% | 8700 kcal |
| Lean-caking | <20% | ≈90% | 8600 kcal |
| Lean | ≈15% | ≈90% | 8700 kcal |
| Anthracite | ≈15% | ≈98% | 9000 kcal |
It is, of course, isn’t all signs which indicate attachment to any mark. Also, coal is divided on technological groups, which divided by caking capacity. Bellow will be shown more details and uses for any marks of coal.
Lignite
Lignite or brown coal is coal with the lowest rank and level of metamorphism. Usually, have fibrous structure. Contains low carbon and gives low heat. Sometimes used for electricity production, but main application is chemical industry. It can be manufactured in liquid.
Long-flame
Long-flame coal is porous and laminate. Coal burns with long flame and makes many soot. it isn’t caking, thus long-flame coal cannot be used alone to make coke, but can be component of blend. Main application is electricity production.
Gauze
Gauze is one of most universal mark of coal. It is with matte or, rarely, metallic shine. Often, attributed to energetic, but can be used to produce electricity, in chemical industry and even coke production.
Oily
Material with matte shine. Burns with white flame, after burning leaves endurable slag, which contains a lot of sulfur. Oily coal uses only in coke production and metallurgy.
Coke
One of most valuable metallurgical marks of coal. Contains a lot of vitrinite, which provides high caking. Coal is gray colored, with lots of cracks. Coke obtained after that uses only in metallurgy, for example, steel production.
Lean-caking
Mark have deep black color, pronounced shine, low caking, and, compared, is less fragile. Due to low caking and some burning features, main use of lean-caking coal is electricity production, rarely, as a component of coke-producing blend.
Lean
Coal with highest level of metamorphism among non-anthracite coals. Coal is fragile, black colored and shiny. Lean coal is burning with short flame and produces a lot of heat. Usually, used to produce to produce electricity, cement and as a component of metallurgical blends.
Anthracite
Anthracite is the most ancient mark of coal with highest containment of carbon. Has rich black color and metallic shine. Mark is remarkable by some other interesting properties, like a ferromagnetism or a high electrical conductivity. Since, anthracite has many uses, including technological, because it is transition station across coals and graphite. Main use of anthracite is still energetic. High containment of connected carbon and high heat combustion can significantly increase production of energy.
UkrainianStudentsBlog 
One response to “Coal marking”
Wow, amazing blog. Was very informative and helpful. Can someone give me the contact information of the author? Would love to give him feedback in person. Wish more students would write about things like these. Got chills after reading.
LikeLike