Too full! Mine class calculation formula!

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 + ∑Q硐...+∑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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