Mathematical Model of Rockmass Behaviour in Underground Coal

Gasification

National Mining UniversityNational Mining University

Vasil Vasil LozynskyyLozynskyy

Research supervisorResearch supervisorV.S FalshtynskyyV.S Falshtynskyy

Language adviserLanguage adviserN.M N.M

NechayNechay

IMPORTANT PROBLEM

The height of caving zone after BUCG

Subsidence hп is defined from expression:

• hп = (0.5…0.6)mв – mз - h; м,

wherewhere mmBB– – coal seam powercoal seam power, , mm; ; mmЗЗ–– power of ashslags layer power of ashslags layer, , mm; ; h = = hСЛ.ПСЛ.П....ККBB rocks power increasing by swellingrocks power increasing by swelling, , mm; ; hсл.псл.п.- .- power of pile swelling rockspower of pile swelling rocks, , mm

Swelling coefficient in dependencies of rocks composition and temperature

Chemi-cal

compo-sition

Rocks indexes %

Heat up temperature, 0 C

Swelling rocks

Non swelling

rocks1000

1100

1150

1200

SiO2 62,5-78<62,5>

781,15 1,45 1,48 1,71

Al2O3

SiO2

0,2-0,41

<0,2>0,41

1,0 1,1 1,18 1,35

C 0,6-4,2<0,6>4,

21,0 1,2 1,32 1,53

Load distribution on rocks layer above underground gasgenerator in BUCCG: а – area №1, seam С5, b – area №4, seam С4,

c- area№5, seam Св10, d- area №7, seam С6.a

b

c

d

Dependencies of rocks pile in rockmass aboveunderground gasgenerator

Change of pile parameters during BUCG

Length of gasgener

ator channel,

m

Spread of long wall movement, m/d

0,5 1,0 1,5

h max,

mm

Vp

max,

m3

Vp

min

m3

h max,

mm

Vp max,

m3

Vp

min

m3

h max,

mm

Vp

max,

m3

Vp min

m3

60 314 910 210 321 917 221 326 924 227

30 235 652 100 240 694 81 244 702 86

25 194 623 89 89 628 72 180 631 75

Rocks of roof and footwall mowing by the geomechanical and thermodynamic factor during underground gasgenerator

U,мм. L, м.

Т, мм.

Y,мм

U,мм. L, м

Т,0С I II III

U,мм. L, м

U,мм. L, м

Parameters of heating the rock mass above the gas generator

(test bench research) а

б

Degree of heating the rock mass of the roof (а) and ground(б):1 – oxygen enriched blast (О2 – 30%), pressure P = 0,4 МПа, row 4; 2 – air blast, pressureР = 0,6 МПа, row 2; 3 – air blast, pressure Р = 0,4 МПа.