Mine Recovery

1. MSHA 2207 November 1981 June 3, 2005 Mine Recovery

2. Northern Mine Rescue Association

3. Introduction • The main objective of recovery work is to put the mine or affected area of the mine back in operation as soon as conditions permit after a mine disaster. • Depending on the conditions, recovery operations can range from a few days work reestablishing ventilation in a small area to many months of costly re-ventilation and rehabilitation work throughout an entire level or section of the mine.

4. Introduction • Your role as a mine rescue team member in recovery work varies as the operation progresses and conditions change. • Until ventilation is reestablished in the affected area, apparatus crews will be needed to assess conditions, rebuild bulkheads, and where necessary, clear debris and stabilize ground conditions.

5. Introduction • Once ventilation has been reestablished and fresh air advanced, non-apparatus crews can take over and rehabilitation and cleanup effort.

6. Assessing Conditions • In order to plan a recovery operation, there must be an initial assessment of the underground conditions. Then, as the work progresses, rescue teams will be making updated reports on the conditions and damages the encounter.

7. Assessing Conditions • Assessment of conditions is necessary for your TEAM SAFETY and also to determine how much rehabilitation work is needed to recover the affected area.

8. Assessing Conditions • One of the main things your team will be checking is the extent of damage to the ventilation system. This includes checking the condition of each of the ventilation controls and any auxiliary fans and tubing.

9. Assessing Conditions • As your team explores and re-ventilates an area, you should be checking for gas conditions and ground conditions.

10. Assessing Conditions • You will also be checking the condition of the: • Track • Water or air lines • Phone lines • And looking for evidence of flooding, flood damage, and smoldering or hot spots in a fire area.

11. OBJECTIVE 1: • The team members will identify the procedures for reestablishing ventilation after a mine disaster

12. Reestablishing Ventilation After a Fire or Explosion • Reestablishing ventilation and bringing fresh air to an area damaged by fire or explosion is the main task of a mine rescue team in a recovery operation. • Once this is done, regular work crews can help with the recovery effort.

13. Reestablishing Ventilation After a Fire or Explosion • In fire area that have been sealed, this means unsealing the area, assessing the damage, and repairing and rebuilding the ventilation system.

14. Reestablishing Ventilation After a Fire or Explosion • If the area has not been sealed, the job of reestablishing ventilation is a little easier. It involves simply assessing the damage and making the necessary repairs to reestablish normal ventilation.

15. Reestablishing Ventilation After a Fire or Explosion • In an area damaged by an explosion, the task is the same: • Assessing damages and repairing ventilation controls • After an explosion, though, a great deal of construction work is usually needed to restore ventilation to proper functioning.

16. Unsealing a Fire Area • Unsealing a fire area requires careful planning. • Opening seals prematurely can cause a re-ignition of the fire and, in mines with explosives gases, could ignite an explosion.

17. Unsealing a Fire Area • Normally, a step-by-step plan for unsealing a fire area is drawn up by the Company mine officials with the advice of Federal and, where applicable, State and Union representatives.

18. Unsealing a Fire Area • WHILE THE MINE RESCUE TEAM MEMBERS DO NOT PLAN THE UNSEALING OPERATION, IT IS IMPORTANT THAT YOU KNOW WHAT THE CONSIDERATIONS AND POTENTIAL PROBLEMS ARE IN SUCH AN OPERATION

19. When to Unseal • The determination of the exact time to unseal a fire area is based on the laws of physics and chemistry, as well as on experience and sound judgment. • A reasonably accurate analysis and interpretation of the gases in a sealed area is possible through proper sampling techniques and with the aid of a chemist experienced in this work.

20. When to Unseal • In addition to the gas conditions, other factors must be taken into consideration when choosing the safest time to unseal a fire area.

21. Visual 1

22. When to Unseal (Visual 1) • The main factors governing the time for unsealing a fire area are: • The extent and intensity of the fire at the time of sealing • The characteristics of the burning material and the surrounding strata • The tightness of the seals

23. When to Unseal (Visual 1) • The main factors governing the time for unsealing a fire area are: • The effect of barometric pressure on the enclosed area. • The effect of temperature on the enclosed area • The location of the fire area with respect to ventilation

24. When to Unseal (Visual 1) • The main factors governing the time for unsealing a fire area are: • The gas conditions as indicated by analysis of air samples taken from behind the seals • Usually the gases analyzed are: • Oxygen • Carbon Dioxide • Carbon Monoxide • Methane • Hydrogen • Nitrogen

25. When to Unseal • In addition to analysis of these factors, local conditions, such as proximity of gas wells to the fires and the extent of the region under seal, must be considered. • Ordinarily, more time will be needed before unsealing a large area than a small area.

26. Visual 2

27. Preconditions for Opening a Sealed Fire Area (Visual 2) • Although each situation is different, experience indicates that no attempt should be made to unseal a fire until: • The O2 content of the air behind the seal is low enough to make an explosion impossible (no matter what quantity of combustible gases is behind the seal) • CO (the gas that indicates combustion) has disappeared or nearly disappeared from the air behind the seal, and • The area behind the seals has been given enough time to cool so that air introduced during the unsealing operation will not rekindle the fire. • Achieving these goals may be difficult, and may require a great deal of time.

28. Preparations for Opening a Sealed Fire Area (Visual 3 • Opening a sealed fire area requires certain preparations: • 1. Adjustments in ventilation should be made so that toxic and explosive gases released from the sealed area are directed into the main exhausts. Also checks should be made in the exhaust airways for any ignition sources (such as telephones or signaling lights) in preparation for moving potentially explosive gases.

29. Visual 3

30. Preparations for Opening a Sealed Fire Area (Visual 3) • Opening a sealed fire area requires certain preparations: • 2. An observer should be at the main fan to ensure it is operating correctly. If the fan slows down or malfunctions, the teams working underground should be withdrawn immediately. Also someone should be monitoring gas levels at the main exhausts. If the fan is electrically driven and exhausting, precautions should be taken so that explosive gases do not come in contact with the fan motor or any other electrical equipment used to operate the fan

31. Preparations for Opening a Sealed Fire Area (Visual 3) • Opening a sealed fire area requires certain preparations: • 3. Checks should be made to ensure that the electrical power in the sealed area has been cut off before unsealing is begun. Cutting the power is important in mines with explosive gas accumulations. In some mines, however, cutting the power may not be advisable; if for instance, it is needed for necessary pumping equipment.

32. Preparations for Opening a Sealed Fire Area (Visual 3) • Opening a sealed fire area requires certain preparations: • 4. Withdraw all unnecessary people from the mine.

33. Methods of Unsealing Fire Areas • There are two basic methods that can be used for unsealing a fire area: • Progressive, or stage ventilation and, • Direct ventilation

34. Progressive, or Stage Ventilation • Is the re-ventilation of a sealed area in successive blocks by means of air locks

35. Direct Ventilation • Is the re-ventilation of the entire sealed area at once.

36. Methods of Unsealing Fire Areas (continued) • Progressive ventilation is the most common method of unsealing a fire area in single-level mines, particularly room-and-pillar mines. Either method can be used, though. • The advantage of progressive ventilation is that gas conditions can be carefully controlled, and the operation can be halted at any point in which conditions become hazardous. • The disadvantage of progressive ventilation is that it is a slow process.

37. Methods of Unsealing Fire Areas (continued) • Direct ventilation is the common method of recovery in multi-level mines. • Direct ventilation can be accomplished quickly. • However, before using direct ventilation, there should be conclusive evidence that the fire has been extinguished.

38. Recovery by Progressive Ventilation • In single-level, room-and-pillar mines, progressive ventilation is the usual method of recovery when the sealed area is large, fire is extensive, or bodies must be removed. • With this method, the sealed area is explored and re-ventilated in successive blocks by the use of air-locks. • As long as conditions remain favorable, the work continues and the entire area can eventually be recovered.

39. Recovery by Progressive Ventilation • Air locking operations should never be undertaken until the O2 content of the air behind the seals has been reduced to at least 2%.

40. Recovery by Progressive Ventilation • During progressive ventilation, a certain amount of air will unavoidably enter the area behind the seals. As the work continues, O2 and explosive gas levels must be carefully monitored, and the operation halted if conditions become dangerous.

41. Recovery by Progressive Ventilation • Recovery by progressive ventilation is very similar to advancing a fresh air base. But it is usually an even slower operation because of the damage that normally is found in a sealed area. • The first step in progressive ventilation is to build a bulkhead at one of the seals on the intake side of the fire area to create a airlock.

42. Recovery by Progressive Ventilation

43. Recovery by Progressive Ventilation • AIR LOCKING OPERATIONS SHOULD ALWAYS BEGIN ON THE INTAKE SIDE OF THE FIRE.

44. Recovery by Progressive Ventilation • Once the air lock is completed and conditions are right for entering the sealed area, a team with apparatus can enter the air lock and break out an opening in the seal. • You may have to wait after removing the first few blocks from a seal for the pressure to stabilize.

45. Recovery by Progressive Ventilation • After the seal is opened, an apparatus team ,or, if necessary, a rotation of teams can enter the sealed area and explore and assess conditions to the point where the next air lock will be built.

46. Recovery by Progressive Ventilation • The distance between airlocks is usually between 200 and 500 feet. It depends on the conditions encountered and the amount of construction work that is needed to prepare an are for re-ventilation.

47. Recovery by Progressive Ventilation • During exploration, the team should note conditions in general. • In particular, they should take: • Temperature readings • And make necessary tests for: • O2 • CO2 • CO • And Explosive gases • Also, when requested, they should collect air samples

48. Recovery by Progressive Ventilation • They should also take measurements for the new air lock that will be built and any additional bulkheads that will be needed in parallel passageways to seal the area. • Once the exploration and assessment is complete, a team or teams can be sent in to construct the first bulkhead of the new air lock and any additional bulkheads needed in parallel passageways to reseal the area.

49. Visual 5

50. Recovery by Progressive Ventilation • In addition, the team will have to prepare the area between the two airlocks for re-ventilation. • This involves repairing ventilation controls and making necessary changes to direct the air to the exhaust airway.