First, the calculation of common section area:
1. Semi-circular arch area = lane width × (alley height + 0.39 × lane width)
2, three-heart arch area = lane width × (lane height +0.26 × lane width)
3, trapezoidal area = (upper bottom + bottom) × lane height ÷ 2
4, rectangular area = lane width × lane height
Second, the wind speed measurement calculation:
V table = n / t (m / s) (usually measured by sideways wind speed)
Where: V: calculated table speed; n: see table reading; t: wind time (s)
V true = a + b × V table
In the formula: V true: true wind speed (wind speed after deducting wind meter error);
a, b: See the table constant for calibration.
V flat = KV true = (S-0.4) × V true ÷ S
Where: K is the correction factor (K=(S-0.4)/S when the wind is measured by the side body method and 1.14 when the wind is measured by the side body method); S is the cross-sectional area of ​​the roadway at the wind measurement location.
Third, the determination of the amount of air:
Q=SV
Q: air volume in the shaft (m3/s); S: roadway area (m2) at the wind measurement location; V: average wind speed (m/s) in the shaft
Example 1: The width of a semi-circular archway is 2m, the wall height of the roadway is 1m, and the wind speed is 1m/s. What is the air volume of this roadway?
Example 2: The cutting area of ​​a coal roadway is 3m2, the air volume is 36m3/min, and the wind speed is over limit?
Fourth, the calculation of mine gas emission:
1. Calculation of mine absolute gas emission (QW)
Q watt = QC (m3 / min)
Where Q is the air volume of the working face; C: is the gas concentration of the working face (gas concentration of return air flow - gas concentration in the incoming air flow)
Example: The gas emission of a mine is 3 m3/min. According to the gas concentration of the total return airway, the supply air volume of the mine should not be less than.
2. Relative gas emission (q watts)
q watt = (m3 / t)
Q watt in the formula: the absolute gas emission of the mine; 1440: 1440 minutes per day;
N: number of days of work (this month); T: production of the month
V. Calculation of air volume in the whole mine:
1. Calculate according to the maximum number of people working at the same time in the underground
Q mine = 4NK (m3 / min)
4: For the provisions of Article 103 of the Regulations, the air supply per person per minute shall not be less than 4 cubic meters per minute; N: the maximum number of people in the well; K: coefficient (1.2~1.5)
2. Calculation of the actual required air volume according to independently ventilated coal mining, excavation, diverticulum and other locations
Q mine = (∑Q mining + ∑Q mining + ∑Qç¡...+∑Q other)×K
Where K: correction factor (take 1.2~1.8)
Sixth, the coal mining face needs air volume
1. Calculated according to the amount of gas emission
Q mining = 100 × q mining × KCH4 (m3 / min)
Where: 100 is the coefficient; q mining: the amount of gas emission from the coal face (relative);
KCH4: Gas emission imbalance coefficient (take 1.4~2.0)
2. Calculated according to the temperature of the mining surface:
Q mining = 60 × V × S (m3 / min)
Where: 60: is the coefficient; V: wind speed of the mining face (0.8~1.0m/s when the temperature is 18~20°C, 1.0~1.5 m/s when the temperature is 20～23°C); S: average of the mining face Break area.
3. Calculated according to the number of people in the face:
Q mining = 4N (m3/min)
4. Calculated according to the amount of explosives:
Q mining = 25A (m3 / min)
In the formula 25: is the coefficient; A: the maximum explosive amount for one-time bursting
5. Check according to wind speed:
15≤Q mining ≤240 (m/min) or 0.25≤Q mining ≤4 (m/s)
In the formula 15 and 0.25: the minimum wind speed (m/min) of the working face (m/s)
240 and 4: maximum wind speed (m/min) (m/s)
Example: 15 people working in a mining face, 5kg of one-time explosive explosives, temperature 20 degrees, gas emission amount is 1 m3/min, what is the air volume required for the mining face?
Seven: Calculation of the required air volume for the driving face
1. Calculated according to the amount of gas emission
Q excavation = 100 × q digging × KCH4 (m3 / min)
KCH4 in the formula: gas emission imbalance coefficient (take 1.2~1.8)
2. Calculated according to the amount of explosives:
Q digging = 25A (m3 / min)
3. Calculated by number of people:
Q mining = 4N (m3 / min)
4, according to the bureau fan suction volume calculation:
Q mining = Q bureau +60VS
In the formula Q: the actual suction volume for the local fan; V: the minimum air volume 1.5m/s; S: the broken area
5. Check according to wind speed:
Coal roadway or semi-coal rock roadway: 15≤Q excavation ≤240(m/min) or 0.25≤Q digging ≤4 (m/s)
Rock Lane: 9≤Q Digging ≤240(m/min) or 0.15≤Q Digging ≤4 (m/s)
Eight, the value of the diverticulum air volume (according to experience)
1. The air volume required for the electromechanical diverticulum: the electromechanical chamber of the independent return air can take 150~200 m3/min;
2. The required air volume of the blasting material library: 60-100 m3/min for small and medium-sized;
3, the charge room needs air volume: 100 ~ 200 m3 / min
9. Calculation of required air volume of other roadways
Calculate separately according to the following methods, using the maximum value
1. Calculated according to the amount of gas emission:
Q other = 100 × q × KCH4 (m3 / min)
2, according to the wind speed check:
Check the value according to the minimum wind speed: Q other = 9S (m3 / min) S is the sectional area
X. Calculation of effective air volume rate of mine
Mine effective air volume: refers to the sum of the air volume of each independent wind location in the mine
Mine effective air volume rate = × 100%
Note: The regulations require that the effective air volume rate of the mine is not less than 85%.
Example: The effective air volume of a mine is 540 m3/min, the wind area of ​​the main fan is 4m2, and the wind speed is 3m/s. Does the effective air volume rate of the mine comply with the regulations?
XI. Calculation of mine air leakage rate
1. The leakage air rate outside the mine = × 100%
Note: Article 121 of the Regulations stipulates that the external air leakage rate shall not exceed 5% when there is no lifting equipment; when it is lifting equipment, it shall not exceed 15%.
2. The air leakage rate inside the mine = × 100%
Twelve, gas accumulation calculation
Gas accumulation: refers to the phenomenon that the accumulated gas concentration is greater than 2% and the volume is ≥ 0.5m3.
Q product = SLC (m3)
Example: A blind lane is 200m long, the section is 3m2, and the gas concentration at 1m inside the fence is 3%. Calculate the concentration of the blind lane.
Note: Blind alley refers to a single laneway with a length of more than 6 meters without ventilation.
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