75D301-18-Q-68676_Questions_&_Answers_7-27-18.pdf

75D301-18-Q-68676

Mine Ventilation Fan System

Questions & Answers

1. Paragraph 1.0 – horns are to discharge vertically – what are the horns and is the fan to be discharging vertically down, up, or horizontal?

Answer: Horns are part of the ductwork through which the mine air is discharged into the atmosphere. The fan discharge is specified as vertical.

2. Paragraph 1.2 – please define the static pressure that the fan will operate against except that the existing fan was to operate against .9” WG. Please advise.

Answer: The current operating point of the existing fan is 33,000 cubic feet per minute at

0.9” of water gauge this specifies the mine resistance. We expect the mine resistance to stay the same or possibly decrease as there are no plans to advance the mine in the future.

3. Paragraph 2.4 – indicates that the fan is to be direct-driven, arrangement 4 with the fan wheel mounted on the motor shaft; therefore no drive shaft is required and since fan is direct-driven there will be no fan bearings. Is this correct?

Answer: The motor is to be located in the electrical control building and connected to the fan through a drive shaft. Mounting the motor in the airflow is not acceptable.

4. Paragraph 3.3 – there is no coupling for arrangement 4 fans. Is this correct?

Answer: Incorrect.

5. Paragraph 3.4 – requires a maximum 60 dBA inside building 44 and 50. Please advise distance from these buildings from the fan.

Answer: The distance from the existing fan to Building #44 is approximately 105 ft. and to Building #50 is approximately 100 ft. Basic distance data can be derived from publically accessible information such as “Google Earth”. The above numbers were measured using “Google Earth”.

6. Specifications call for only a discharge silencer. The fan noise is generated in a spherical form requiring inlet and outlet silencers, therefore there should be two silencers, please confirm.

Answer: The minimum requirement is that a discharge silencer be installed to comply with the noise specifications. Additional silencers are permitted. The significant requirement is compliance with the noise specifications.

7. Paragraph 3.6 – please advise “U” factor of the insulation on the electrical control room to calculate requirements for heating, cooling and ventilation.

Answer: The contractor is expected to design the building including all components and therefore should be able to calculate the “U” factor.

8. Paragraph 3.6.1.6 – What is to be considered a suitable temperature range?

Answer: The heating and cooling systems shall provide for a temperature range suitable for all components installed in the fan building. A range of 60̊ F to 78̊ F will be acceptable if it is suitable for all components installed in the building.

9. Paragraph 3.6.1.8 – What are the current industry standards for building size?

Answer: The building size must be adequate to allow for proper installation, maintenance and replacement of all components. Adequate working clearance must also be provided.

10. Paragraph 3.8.8 – What is the purpose of the 4” x 36” damper?

Answer: The purpose of the 4” X 36” damper is to allow for collection and draining of any water that may collect in the tubing.

11. Paragraph 3.8.14 – Please advise how many inspection trips would be required by : 1.

The fan manufacturer, 2. The fan manufacturers local representative.

Answer: The contractor is to be responsible for the complete installation. Any trips by the fan manufacturer or the fan manufacturer’s representative are only necessary if the contractor cannot answer questions or make any necessary corrections.

12. Paragraph 4.0 – Fan Performance – please note that the previous proposal indicated the fan would operate at 100,000 cfm at 1.9” and 96.3 BHP, which allowed only .4” WG available for airflow resistance in the tunnel. Please provide static pressure for the fan selection.

Answer: The current operating point of the existing fan is 33,000 cubic feet per minute at

0.9” of water gauge this specifies the mine resistance. We expect the mine resistance to stay the same or possibly decrease as there are no plans to advance the mine in the future.

13. Paragraph 5.0 - The specifications indicate only an outlet silencer which would be inadequate to meet the noise specification. Silencers would be required at each end of the fan. Please advise.

Answer: The minimum requirement is that a discharge silencer be installed to comply with the noise specifications. Additional silencers are permitted. The significant requirement is compliance with the noise specifications.

14. If the fan is required to meet decibel noise levels for South Park Township noise regulations, we must be provided with this information and this paragraph also indicates residential noise levels are applicable to this site. Please provide any additional residential noise level requirements.

Answer:

• Business Park: At no point on or beyond the boundary of any lot within these districts shall the exterior noise level resulting from any use or activity located on such lot exceed a maximum of sixty (60) dBA.

•Residential: At no point beyond the boundary of any lot within these districts shall the exterior noise level resulting from any use or activity located on such lot exceed a maximum of fifty-five) dBA.

15. Do you require spring vibration isolators for the fan base and flexible connections at inlet and outlet of the fan between the fan and the silencers?

Answer: The contractor is expected to install the fan in accordance with the fan manufacturer’s recommendations.

16. Paragraph 5.2 – recommended spare parts would be provided after receipt of approved drawings. Please advise.

Answer: The spare parts list may be provided after receipt of approved drawings.

17. Are there any plans to increase the maximum CFM in the future?

Answer: No. The expectation is that a fan will be chosen by the contractor that, with various blade settings and speed settings, will provide approximately 15,000 cfm to

100,000 cfm. CDC/NIOSH expects that the motor will be rated at approximately 100 hp.

There are no plans to increase the fan capacity above these specifications.

18. Are there any plans for the mine that would increase the mine resistance?

Answer: No. The current operating point of the existing fan is 33,000 cubic feet per minute at 0.9” of water gauge this specifies the mine resistance. We expect the mine resistance to stay the same or possibly decrease as there are no plans to advance the mine in the future.

19. Are explosion doors and/or air reversal doors required? What is configuration?

Answer: We expect MSHA acceptable explosion doors to be installed at the top of the shaft. Air reversal doors are not required.

20. Will the fan ventilate both mines?

Answer: No, only the Safety Research Mine. The Experimental Mine is isolated from the

Safety Research Mine and has a separate fan installation.

21. Are shaft seals required in the event of a fire?

Answer: No.

22. What is the existing shaft profile, depth and diameter?

Answer: It’s a concrete lined; 20 ft. deep, 6 foot by 10 foot rectangle opening.

23. Will the same shaft be used?

Answer: Yes.

24. Will the contractor be allowed to work on an accelerated time line for outage?

Answer: No. The available on-site work week will be Monday through Friday from 6:30 am to 6:00 pm.

25. Is this an MSHA inspected site?

Answer: The Safety Research Coal Mine is not an MSHA inspected mine at this time.

We are in the process of upgrading the mine to MSHA standards and intend to have

MSHA inspect the mine in the future. Therefore, the fan must comply with MSHA regulations and policies when successfully installed.

26. Are MSHA certified workers required?

Answer: No. An MSHA certified electrician shall inspect the completed work and certify that it complies with the National Electrical Code and federal mining regulations.

27. Is there any monitoring on the existing fan?

Answer: The existing fan includes a 24 hour paper fan chart recorder.

28. Is the fan itself (reverse blades) to be reversible?

Answer: No, but a reversible starter is specified for the electric motor.

29. Clarify fan performance when operated in reverse.

Answer: Contractor shall estimate performance of fan in reverse (blowing) mode; there is no expectation of same volume being achieved in both forward and reverse directions.

30. Substation 216, what is the load now?

Answer: The load is minimal; the mine office (Building #50) and the current 10 HP fan.

The substation includes three 100 KVA single phase transformers.

31. Relative to the noise specification, what are the distances to the site boundary?

Answer: The distance to the site property line in the east direction is approximately 750

ft. and to the south is 850 ft. Basic distance data can be derived from publically accessible information such as “Google Earth”. The above numbers were measured using “Google

Earth”.

32. Do the noise specifications apply to all modes of fan operation?

Answer: Yes.

33. Regarding government furnished property, are there any available existing copper or fiber optic lines available?

Answer: No

34. Clarify the alarm, remote monitoring and remote control locations.

Answer: The building housing the electrical power, controls, monitoring, and motor shall include the pressure monitoring (7 day paper fan chart recorder) vibration, temperature and electrical monitoring as specified in 3.8.5. An audible and visual alarm shall be mounted on the outside of the building.

The mine foreman’s office, Building # 50, shall include (3.8.6) a 24 hour paper fan chart recorder and all of the vibration, temperature and electrical monitoring displays discussed above. The connection from the fan building to the mine foreman’s office shall be contractor supplied fiber or copper. In addition the mine foreman’ office shall include the capability of starting, stopping, changing speed and reversing the fan motor. There shall also be a means of silencing the audible and visual alarm.

The telemetry specified in 3.8.10 shall be suitable for connection to a fiber telephone system. CDC/NIOSH will integrate the dialer into the site telephone system.

35. Are any single line diagrams available?

Answer: Attachment 3 is a single line diagram. There are additional facility drawings showing both topographic and utility information available. These would be made available after a non-disclosure agreement is signed and transferred in a secure format.

Government facility maps and building plans are considered Controlled Unclassified

Information (CUI) that have restrictions from public release.

36. What is the distance of the utility easement from Columbia gas line?

Answer: The Columbia Gas transmission line is located just to the east of the existing mine fan. Any building structure will have to be positioned outside the utility easement right of way (25 feet to centerline) of that pipeline.

37. Is there an objection to use aerial power lines if use Pad 213?

Answer: An insulated cable assembly with ground such as quadruplex, GGC or similar cable is acceptable.

38. The statement of work indicates that “The current operating point of the existing fan is

33,000 cubic feet per minute at 0.9” of water gauge.” Where is this pressure measured and the approximate cross-sectional area at the measurement location?

Answer: The existing fan is placed within a structure that contains three distinct parts: a) the 90° shaft top compartment, the fan compartment, and the 90° exhaust elbow The 90° shaft compartment is rectangular in shape and allows the air moving vertically through the shaft to turn 90° and enter the circular fan. The 90° rectangular exhaust elbow compartment allows the air exiting the fan to turn vertically and enter the atmosphere.

The picture titled “Mine Portal and Fan” shows the location of the tubing for the fan water gauge chart recorder. The inlet to the tubing is at the junction of the rectangular exhaust elbow and the circular fan compartments. The circular fan compartment is approximately 54” in diameter.

39. Please measure and report the 3 phase motor amps and 3 phase voltage while operating at the current mine ventilation operating point. Please also take note of the existing fan motor nameplate data and report.

Answer: Actual values measured on 07/26/18; 7.0 Amps, 488 Volts.

Motor nameplate data: 10 hp, 13.5, Amps, 440 Volts.

40. Please send a site layout drawing of the area of around the existing fan, surrounding roadways, buildings, and other features.

Answer: The area of around the existing fan, surrounding roadways, buildings, and other features can be viewed on publically accessible web sites such as “Google Earth”.