1) Mineral coal (or simply "coal") and anthracite coal

1.1) First 1-2 letters in coal's grade name mean one of 10 grades by volatile matter:

D = long-flame coal (from Russian "Dlinnoplamenny")

G = gas coal (from Russian "Gazovy")

GZh = gas fat coal (from Russian "Gazovy Zhirny")

Zh = fat coal (from Russian "Zhirny")

KZh – coking fat coal (from Russian "Koksovy Zhirny")

K = coking coal (from Russian "Koksovy")

K 2 = coking second coal

SS (or CC in some sources) = weakly caking coal (from Russian "Slabo spekayuschiysya")

OS = lean caking coal (from Russian "Otoschenny Spekayuschiysya")

T = meager coal (from Russian "Toschy")

PA = semi-anthracite coal (from Russian "Polu- antratsit")

A = anthracite coal

Usage of (mineral) coal and anthracite by grades:

• For coking – grades "G", "Zh", "K", "OS"; sometimes "D" and "T";
• For burning in boiler houses – grades "D", "G", "A" and "PA";
• For burning at electric power stations – grades "SS", "OS" and "T".

There are usually some letters or numbers after "grade" letters in coal's name, for example, DOM or K9. Letters mean classes of coal (by fraction size), and numbers mean the least thickness of plastic layer for some grades.

1.2) Classes of coal (by fraction size):

P = "plate" > 100 mm

K = "large" (from Russian "Krupny") 50- 100 mm

O = "nut" (from Russian "Orekh") 25- 50 mm

M = "little" (from Russian "Melky") 13- 25 mm

S = "kernel" (from Russian "Semechka") 6- 13 mm

Sh = "burgy" (from Russian "Shtyb") 0- 6 mm

R = "ordinary" (from Russian "Ryadovoy") underground mine 0- 200 mm , open pit mine 0- 300 mm

Class of coal is indicated by one or few letters. Letters of class are indicated right after grade letters. The fraction of the specific coal grade is indicated by classes in its name = the least value of the least class and the largest value of the largest class.

For example,

• ASh = anthracite coal ("A") with "burgy" class ("Sh")
• GR = gas coal ("G") with "ordinary" class ("R")
• DOM = long-flame coal ("D") with class 13- 50 mm (O = 25- 50 mm , M = 13- 25 mm – we take the least value from the least class, i.e. 13 mm from "M" and the largest value of largest class, i.e. 50 mm from "O")
• SSSSh = weakly caking coal ("SS") with class 0- 13 mm (S = 6- 13 mm , Sh = 0- 6 mm )
• TOMSSh = meager coal ("T") with class 0- 50 mm (O = 25- 50 mm , M = 13- 25 mm , S = 6- 13 mm , Sh = 0-6mm)

1.3) The coals of grades "G", "GZh", "Zh", "KZh", "K" and "OS" can be classified by their caking property. The caking property is indicated by a number that means the least thickness of plastic layer (in mm).

For example,

• K9 = coking coal with the least thickness of plastic layer in 9 mm
• KZh12 = coking fat coal with the least thickness of plastic layer in 12 mm

1.4) Basic characteristics of coal grades

In direction from "D" to "A" grade there is the lowering of humidity, oxygen and hydrogen level:

• Humidity lowers from 14% for "D" to 4,5-5% for "T" and "A" grades
• Level of oxygen lowers from 15% for "D" to 1,5% for "T" and "A" grades
• Level of hydrogen lowers from 5,7% for "D" to 1,5% for "T" and "A" grades

The level of sulphur, nitrogen and ash doesn't depend on grade.

The combustion heat growths from 32,4 MJ/kg (7750 kcal/kg) for "D" grade to 36,2-36,6 MJ/kg (8650-8750 kcal/kg) for "K" grade and then lowers to 35,4-33,5 MJ/kg (8450-8000 kcal/kg) for "PA" and "A" grades.

1.5) Correspondence of the Russian and the US coal classifications
 

2) Brown coal
 

Brown coals have only "B" letter in their name followed by numbers from 1 to 3 that mean the group of coal by its humidity:

B1 – humidity >40%

B2 – humidity 30-40%

B3 – humidity < 30%