# Presentation: 517670

##  VENTILATION

- A principal control for dust as well as methane

- DUST CONTROL
- CONTNUOUS MINERS AND ROOF BOLTERS
- BEST PRACTICES

## FACE VENTILATION METHODSContinuous Miners

**Blowing ventilation with scrubbers**

**Exhaust ventilation with scrubbers**

**Exhaust ventilation without scrubbers**

## BLOWING FACE VENTILATION

**BLOWING FACE VENTILATION**
**DUST SCRUBBERS**

- NIOSH Dust Control Handbook – Recommended Reading

## BLOWING FACE VENTILATION

**BLOWING FACE VENTILATION**

- 5,899 cfm Scrubber

- 7,000 cfm  400 ft/min

- > 7,000 cfm

- Line Curtain

- 1.  End of Line curtain airflow approximately 1000 cfm greater than scrubber.

- 2.  Airflow measured with scrubber off.

- 4.  Operator stands in fresh air (out of red zone).
-  This may require adjustment of curtain during       movement of the continuous miner .

- 3.   Use measured scrubber airflow not the name plate.

- 5.  Shuttle car operator is on the curtain side of the entry.

- 6.  Scrubber discharge on off curtain side.

## BLOWING FACE VENTILATION

**BLOWING FACE VENTILATION**
- CURTAIN AIRFLOW MEASURED WITH SCRUBBER ON
- BAD PRACTICE
**NOT RECOMMENDED**

- 5,899 cfm Scrubber

- 7,000 cfm

- 3,000 cfm

- Line Curtain (>40 ft.)

*Where’s the air ?*

- 1.  Measuring the end of curtain airflows with the scrubber on can produce erroneous results.

- 2.  Providing less makeup air than the scrubber requires can significantly increase re-circulation of dusty air.

- 4. Airflow at the inlet of the curtain should be greater than at the curtain outlet.

- 3.  May cause miner operator and shuttle car operator to be in dusty air.

- >7,000 cfm

## EXHAUST FACE VENTILATION

**EXHAUST FACE VENTILATION**
**DUST SCRUBBERS**

## EXHAUST FACE VENTILATION

- WITH SCRUBBER

- MEAV > 60FT/MIN

- 1.  Curtain airflows measured with the scrubber off.

- 3.  Miner operator remains in intake air outby the end of the curtain.

- 2.  Curtain airflow greater than measured scrubber airflow.

- 4.  Curtain set back should be far enough to capture scrubber exhaust.

- 5.  Shuttle car operator located on off curtain side.

## 2.  Keep the end of the curtain or tubing within 10 feet of the face.  ( Or as stated in Vent Plan)

- MEAV > 60FT/MIN

- 2.  Keep the end of the curtain or tubing within 10 feet of the face.  ( Or as stated in Vent Plan)

- 1.  Recommend that the mean entry air velocity be as high as possible without degrading line curtain integrity.  Face air quantity usually has the greatest impact on dust reduction.

- 3.  Maintain the line curtain and keep leakage to a minimum.

- EXHAUST FACE VENTILATION
- WITHOUT SCRUBBER

## Best PracticesBlowing Face Ventilation

- Keep miner operators/ helpers on intake side of curtain in fresh air.
- Shuttle car operator should be located on curtain side of the entry.
- Scrubber should always exhaust on the return/off curtain side of the entry.
- The end of curtain airflow should be measured with the continuous miner at the face and the scrubber off.
- The minimum airflow at the end of the line curtain should provide the required makeup air for the dust scrubber to work properly.
- To prevent dust bypassing or passing through the scrubber from being drawn back to the operator’s position, it is recommended that the end of line curtain air quantity be 1000 cfm greater than the measured scrubber airflow.

## Best PracticesExhaust Face Ventilation

- Operators/helpers should remain on the intake side of the entry.
- Scrubbers should always exhaust on the return/curtain side of the entry.
- Like the blowing curtain, the end of the line curtain airflow should be measured with the continuous miner at the face with the scrubber off.
- The line curtain should be hung snugly to the roof and floor to reduce as much short circuiting of intake air as possible.
- There is no recommended maximum airflow to the face.  All available airflow should be directed to the face.
- The minimum airflow should be greater than the measured scrubber airflow with a minimum of a 60 fpm mean entry air velocity.
- Shuttle car operator should be located on off curtain side of entry.
- When dust **scrubber not used** end of curtain or tubing should be within 10 feet of the face.  When dust scrubber is used the end of the curtain should be set back far enough to capture scrubber exhaust.

## BLOWING FACE VENTILATION

- ADVANTAGES

- DISADVANTAGES

- 1.  Easier to maintain than exhaust

- 2.  Provides a better sweep of the face for methane dilution.

- 1.  Shuttle car operators are in return air.

- 3.  Incorrect balance of airflow may cause re-circulation or over powering of scrubber inlets.

- 2.  Miner operator must remain in fresh air at the end of the line curtain during cutting of coal.

## EXHAUST FACE VENTILATION

- ADVANTAGES

- DISADVANTAGES

- 1. Shuttle car operator is in fresh air during cutting of coal.

- 2.  Miner operator has more options as where to stand and still remain in fresh air while cutting coal.

- 3.  Typically, does not interfere with inlet capture efficiency.  .

- 1.  Curtain is hard to maintain.

- 2.  Typically does not provide a fresh air sweep of the face that is as effective for methane dilution as blowing ventilation.

## CROSS CUTS WITH BLOWING CURTAINPIB03-28

- CROSS CUTS WITH BLOWING CURTAIN**PIB03-28**

**Depending on specific mining**
**circumstances, an additional best**
**practice for turning crosscuts is to allow**
**the remote-controlled continuous miner**
**(CM) operator the option to be**
**positioned on the inby side of the**
**intersection.**

## CROSS CUTS WITH EXHAUST CURTAIN

- OPERATOR’S POSITION

- Preferably, crosscuts should be turned with exhaust curtain.  This may require hanging the continuous miner cable.

## Mean Entry Air Velocity

**§ 75.326 Mean entry air velocity.**
- In exhausting face ventilation systems,
- the mean entry air velocity shall
- be at least 60 feet per minute reaching
- each working face where coal is being
- cut, mined, drilled for blasting, or loaded,
- and to any other working places as
- required in the approved ventilation
- plan. A lower mean entry air velocity
- may be approved in the ventilation
- plan if the lower velocity will maintain
- methane and respirable dust concentrations in accordance with the applicable levels. Mean entry air velocity shall be determined at or near the inby end of the line curtain, ventilation tubing, or
- other face ventilation control devices.

## Measure Height

**6 ft.**

**8.5 ft.**

**6.5 ft**

**End of **
**Exhaust Curtain**

**16.5 ft**.

- 8,000 cfm

- Measure Width

- Curtain Airflow

## Area = H x W = 7 x 16.5 = 115.5 sq ft

- 8,000 cfm

- Ave Height = (5 + 6.5 + 5.5) / 3 =

- Ave Height = (6+8.5+6.5)/ 3 = 7 ft.

- Width = 16.5 ft.

- Calculated Ave Velocity =

- Calculated Ave Velocity = Air Quantity (cfm)/ Area (sq ft)

- MEAV = 8,000 cfm / 115.5 sq ft =

- 69.26 ft/min

**End of **
**Exhaust Curtain**

## BIG

- PROBLEMS

## Slide 19

## The immediate intake and return should remain free of equipment.

- WHERE’S THE AIR ?

**The immediate intake and return should remain free of equipment**.

##   Haulage through the intake crosscut should be discouraged.

**I’M  CHOKING HERE !**

-   **Haulage through the intake crosscut should be discouraged.**

** ****Curtain integrity should be maintained.**

## Body Size can Affect Air Readings

**6 ft.**

**3 ft.**

**Miner’s Size  1 foot wide by 6 feet high**
**Takes up an area of 6 square feet**

**V = 300 fpm**
**A = 18 square feet**
**Q = 5,400 cfm**
**V = 300 fpm**
**A = 12 Square feet  ( 18 - 6 )**
**Q = 3,600 cfm**

**Foreman reports 5,400 cfm when he actually only has 3,600 cfm**

**Body Size can Affect Air Readings**

## LINE CURTAIN

- ANEMOMETER

- Check anemometers for damage and current calibration.

## EXHAUST TUBING

- 1.  A Pitot Tube traverse should be used to measure airflow in ventilation tubing and dust scrubbers.

- 2.  Accepted method should be utilized.

## Using a Pitot Tube requires hands on training.

**Stick this where ?**

- VENT TUBING

## FACE VENTILATION 

- ROOF BOLTERS

- While most of the roof bolter operator’s dust exposure comes from upwind sources (e.g., the continuous miner), some bolting machines allow a significant amount
- of dust to escape the dust collector system, thus contaminating the region around the bolter.
- Such contamination is more likely when an insufficient amount of clean air is available to dilute
- the dust.

## VENTILATIONBEST PRACTICE

**EXHAUST LINE CURTAIN NO SCRUBBER** – Do not bolt down wind of the continuous miner.
**EXHAUST OR BLOWING LINE CURTAIN WITH SCRUBBER** -  Design mining cycle to limit the time the continuous miner is upwind of the bolter.
**AUXILLARY VENTILATION AND EXHAUST TUBING** – Utilize soft tubing (bologna skin) attached to fan exhaust to route return air downwind of the bolter.

## DOWNWIND OF MINER

**2.5 mg/m****3**

- 1.0 mg/m3

- 25,000 cfm

**3,000 cfm**

**DOWNWIND OF MINER**

- + 1.5 mg/m3

## DOWNWIND OF MINER

**1.75 mg/m****3**

- 1.0 mg/m3

- 25,000 cfm

**6,000 cfm**

**DOWNWIND OF MINER**

- DOUBLE AIR TO BOLTER

-  = CINTAKE  + CBOLTER   x  Q1 / Q2
-  = 1.0 + 1.5 x 3000/6000 = 1.75

- SIMIPLE DILUTION

## Slide 30