2. GENERAL HEADING OF
VENTILATION SURVEY
AIR
QUANTITY
SURVEY
PRESSURE
QUANTITY
SURVEY
TEMPERATU
RE SURVEY
AIR QUALITY
SURVEY
3. Importance of
ventilation survey
Check and
supply of
air
Detection of
leakage
Size of airways
Alteration in
magnitude and
course of
airways
Ventilation for
control of fire
and other
explosion
5. PRESSURE
REQUIREMENT
1> OBTAIN A PRESSURE
GRADIENT ALONG THE
CIRCUIT
2> DETERMINING THE
VALUES OF FRICTION FACTOR
FOR VARIOUS TYPES OF
AIRWAYS
6. AIR REQUIREMENT
IN THE WORKINGS:-
SUPPLYING THE WORKERS
WITH BREATHABLE AIR
DILUTING IMPURITIES IN
MINE AIR TO SAFE
CONCENTRATIONS
DILUTING HEAT AND
HUMIDITY OF MINE AIR
8. DILUTING IMPURITIES IN MINE
AIR TO SAFE CONCENTRATIONS
1>THE DILUTION OF METHANE
IS THE DETERMINING FACTOR
IN MINES .
2>DGMS RECOMMENDS TO
KEEP THE INFLAMMABLE
GASES BELOW 0.75%.
3>IF ELECTRICAL APPARATUS
ARE USED METHANE SHOULD
KEPT BELOW 0.5%
9. THE RATE OF AIR FLOW Q
REQUIRED TO DILUTE THE
METHANE
GAS IN INTAKE AIR + GAS ADDED IN
THE WORKINGS = GAS IN EXHAUST
AIR
Q ×a +q =( Q + q) c
Q = q/(c−a)−qc/ ( c−a) m3 /min
a = concentration of gas present in
intake air
q = rate of gas emission m3 /min
10. IF THE MINE IS TO BE PLANNED FOR
DEPTHS FOR WHICH NO METHANE
EMISSION DATA CAN BE OBTAINED , IT
WOULD BE WISE TO ALLOW A 10 %
INCREASE IN THE RATE OF GAS EMISSION
FOR EVERY 100M DEPTH .
RADON DOUGHTERS [RADIOACTIVE
MINERALS ] :-- MAXIMUM PER LIMIT = 1/10
U Ci/m3
1 Ci = 37 BILLION DPS
1mCi = 37000DPS . MINIMUM 0.5 M3/S
SHOULD BE DELIVERED FROM A TUBE
OUTLET AT A INSTANCE NOT EXCEEDING
9M FROM FACE FOR EVERY PAIR OF MAN
MINING URANIUM CORE
11. DILUTING HEAT AND HUMIDITY
OF THE MINE AIR
1>It is difficult to estimate the quantity of air
necessary to reduce the temperature of air at
the face , This depends on many factors .
2> heat from sources like machines , men etc are
easily measurable .
3> heat due to spontaneous heating is more
difficult to estimate
Q = ( q × p ×dL )/ (Ad ×Cp×dT)
Q = quantity of air flowing per unit time
q = rate of heat transfer from strata to air
P= perimeter
dL = length of airway
dT =rise in temperature
12. At Ventilation shaft with no
winding equipment = 15m/s
At Ventilation shaft only used for
mineral hoisting = 12m/s
At Ventilation shaft for man
winding and haulage road = 8m/s
other roadways = 6m/s
conveyor roads ,loading pits = 4m/s
working faces in development
,depillaring = 4m/s
13. PRODUCING SUFFICIENT FACE AIR
VELOCITY FOR COMFORTABLE
WORKING CONDITIONS
1> FACE VELOCITY OF 0.5 TO
2.0 m/s FOR COMFORTABLE
WORKING
2> VELOCITIES ABOVE THIS
CAUSE DISCOMFORT
3> FLOW AT FACE SHOULD BE
TURBULENT
14. AIR REQUIREMENT IN
DRIFTS AND TUNNELS
AIR QUANTITY USEDAT DRIFTS
AND TUNNELS IS GREATER TO
CLEAR THE GASES
• EXTREMELY HOT FACES 0.75 M3 S-1 PER
M2 IS USED
IN HIGHLY GASSY COAL
HEADINGS , TO DILUTE THE
METHANE
•IN ANY CASE QUANTITY OF 6 m3
min -1 per man
15. T = 2.303 (Vin/Q) Logq/(Vm.C)+(V-
Vm)/Q
Vm =vol of tunnel mixing of gases
produced at face
q = total volume of noxious gas
m = mass of noxious gas
q’ = vol of noxious gas produced
V= vol to tinnel
C= conc at time t
16. CALCULATION OF RATE OF CH4
EMISSION FROM BROKEN COAL
Iu = b .r.t (Xo −X1) M3/MIN
B = WIDTH OF COAL FACE IN METRE
R = RATE OF FACE ADVANCE M/MIN
T = BULK DENSITY OF COAL TONE/M3
Xo, X1 = ACTUAL AND RESIDUAL METHANE %
17. AMOUNT OF AIR REQUIRED
Qz = 100.Iu/ (C−Co) M3/MIN
Iu = RATE OF METHANE EMISSION
IN PHASE AFTER 30 MIN AFTER
BLASTING M3/MIN
C , Co = PERMISSIBLE GAS
CONCENTRATION AT FACE AS
INTAKE
18. CALCULATION OF AIR RERQUIRED ON
THE BASIS OF EMISSION AND NOXIOUS
GAS WITHDRAWL
Qz = W/ (Kt.To ) In ( 100 Imax To + Co .W)/CW
M3/MIN
W= VOL OF MIXING ZONE BOUNDED BY THE
END OF VENTILATION PIPE AT THE FACE M3
Kt = COEFFICIENT OF TURBULENT (= 0.4)
To = TIME WHEN MAXIMUM METHANE
CONCENTRATION IS OBSERVED AT PHASE
IMMEDIATELY AFTER BLASTING IN MINUTES
Imax = MAXIMUM METHANE OUTPUT IN FACE
ZONE M3/MIN
19. QUANTITY ESTIMATION BASED ON NITROUS
FUMES AFTER BLASTING
Qz = 17 S/T √Ψ .B.b/s M/MIN
T = PERIOD OF UTILIZATION IN MIN
B = AMOUNT OF EXPLOSIVES BLASTED IN 1
TIME TAKEN AS EQUAL TO 100/Kg FOR COAL ,
40 Kg FOR ROCK
Ψ = SIZE OF COEFFICIENT OF WETNESS
B = WIDTH OF COAL FACE
20. QUANTITY ESTIMATION BASED ON DUST
FACTOR
Qz = SVo 60 M3/MIN
S = CROSS SECTION AREA M2
Vo = OPTIMUM RATE OF FLOW
BASED ON OUTPUT ( COAL )
Qz = 2.5 (Td)M3/MIN
Td = DAILY OUTPUT IN TONNE
21. RATE OF AIR FLOW
MINE
WORKING
MINIMUM
POSSIBLE
OPTIMUM
POSSIBLE
MAXIMUM
POSSIBLE
ROBBING
FACE
0.9 1.6 3.0
DEVELOP
MENT
FACE
0.3 0.6 -
DRIVE
WITH
CONVEYO
R TOP
POINT
0.7 1.3 1.8
22. FOR DEPILLARING AREA
Q = 100 Iz N / ( C− Co ) M3/MIN
Iz = MEAN METHANE EMISSION FROM
PILLAR RIB IN M3/MIN
N = COEFFICIENT EQUILIBRIUM OF
METHANE EMISSION
C = PERMISSIBNLE GAS CONC IN RETURN
Co = PERMISSIBLE GAS CONC IN INTAKE
24. TOTAL QUANTITY OF
MINE
Qsh = [ ∑ Qut.sch + 1.1 ( ∑ Qp + ∑Qo .v + ∑ Qk +
∑Qut) ] Kz-u
Qut.sch = AIR REQ TO VENTILATE IN A
DISTRICT
Qp = VENTILATON OF DEVELOPMENT FACE
Qov = VENTILATION OF ISOLATED WORKING
Qk = AIR FOR ROOMS OUTSIDE THE DISTRICT
Qut = LOSSES THROUGH VENTILATION
DEVICES
25. LEAKAGE OF AIR
BETWEEN THE FAN AND THE FACE
IN A MINE A LOT OF AIR IS LOST
THROUGH LEAKAGE .
THE VOLUMETRIC EFFICIENCY OF
DISTRIBUTION OF AIR IN MINES
VARY FROM 10 % TO 85% .
UNDER AVERAGE CONDITIONS 45%
TO 55% OF AIR IS CIRCULATED BY
THE FAN
26. LEAKAGE ACROSS NEWLY
FORMED GOAF
DISTANCE BETWEEN
INTAKE AND RETURN
GATES
LEAKAGE ACROSS
GOAF AS PERCENTAGE
OF AIR ON THE FACE
45 20
90 10
180 5
27. FAN drift pressure Leakage at pit top
1.25 11.7
2.50 16.3
3.75 21.0
5.00 23.3
6.25 25.7
28. PRESSURE
REQUIREMENT
THE PRESSURE GRADIENTS AIDS IN
DETERMINING REGIONS OF EXCESIVE
RESISTANCE AND FEASIBILITY OF
CORRECTING THE CONDITIONS.
IF THE MINE CONSISTS OF SEVERAL PARALLEL
SPLITS , THE PRESSURE REQUIRED FOR THE
ONE WITH THE LARGEST RESISTANCE IS
GENERALLY TAKEN AS THE ACTUAL PRESSURE
REQUIREMENT
29. THIS INVOLVES THE CONTROL OF
QUQNTITIES FLOWING THROUGH THE
OTHER SPLITS BY THE INSTALLATIONS OF
REGULATION IN THEM .
INSTALLATION OF REGULATORS IS A
SIMPLE MEANS OF VENTILATION
CONTROL AND SHOULD BE ADOPTED IF
THE DEGREE OF REGULATION AFFETS
ONLY A MINOR NUMBER OF SPLITS
30. CALCULATION OF RESISITANCE OR
PRESSURE LOSS
P = RQ.Q
TOTAL RESISTANCE =
FRICTION LOSS + SHOCK
RESISTANCE
