In the matter of Petition for Modification
Consolidation Coal Company
Blacksville No. 2 Mine
I.D. No. 46-01968 Docket No. M-97-079-C
Date Issued: 05/15/1998
PROPOSED DECISION AND ORDER
On May 3, 1997, a petition was filed seeking a modification of the application of 30 CFR 75.1002 to Petitioner’s Blacksville No. 2 Mine, located in Monongalia County, West Virginia. The Petitioner alleges that the alternative method proposed in the petition will at all times guarantee no less than the same measure of protection afforded by the standard.
MSHA personnel conducted an investigation of the petition and filed a report of their findings and recommendations with the Administrator for Coal Mine Safety and Health. After a careful review of the entire record, including the petition, and MSHA’s investigative report and recommendation, this Proposed Decision and Order is issued.
Finding of Fact and Conclusion of Law
The alternative method proposed by the Petitioner (as amended by the recommendations of MSHA) will at all times guarantee no less than the same measure of protection afforded the miners under 30 CFR 75.1002.
On the basis of the petition and the findings of MSHA’s investigation, Consolidation Coal Company is granted a modification of the application of 30 CFR 75.1002 to its Blacksville No. 2 Mine.
ORDER
Wherefore, pursuant to the authority delegated by the Secretary of Labor to the Administrator for Coal Mine Safety and Health, and pursuant to Section 101(c) of the Federal Mine Safety and Health Act of 1977, 30 U.S.C., sec. 811(c), it is ordered that Consolidation Coal Company’s Petition for Modification of the application of 30 CFR 75.1002 in the Blacksville No. 2 Mine is hereby:
GRANTED, for the high voltage longwall equipment conditioned upon compliance with the following terms and conditions:
1. The nominal voltage of the longwall power circuit(s) supplying the shearer shall not exceed 4,160 volts. The nominal voltage of the other longwall power circuits shall not exceed 2,400 volts.
2. The nominal voltage of the longwall control circuit shall not exceed 120 volts.
3. Ground-fault current for the high-voltage power circuits shall be limited by a neutral grounding resistor to not more than 0.50 ampere.
4. Each high-voltage motor circuit and shearer circuit shall be provided with instantaneous ground-fault protection set at not more than 40 percent of the ground-fault current limited by the neutral grounding resistor or 0.125 ampere, whichever is less.
5. Each high-voltage circuit supplying power from a longwall power center to a starter enclosure shall be provided with ground-fault protection set at not more than 40 percent of the ground-fault current limited by the neutral grounding resistor or 0.125 ampere, whichever is less. A time delay shall be permitted for coordination with downstream ground-fault protection devices. The time delay shall be set at the lowest practical value that permits reliable coordination; however, in no case shall the time delay exceed 0.250 second.
Where two high-voltage cables are used to supply power to a common bus in the high-voltage starter enclosure and each cable has a ground-fault relay, each individual relay shall be set at appropriate values based on the number of relays.
6. The longwall power circuits shall be provided with backup ground-fault protection that shall deenergize the primary of the affected transformer in the longwall power center if a ground-fault occurs with the neutral grounding resistor open. This protection shall be set at 40 percent of the maximum voltage that could appear across the neutral ground resistor if a ground-fault occurs. A time delay for coordination with downstream ground-fault protection devices shall be set at the lowest practical value that permits reliable coordination; however, in no case shall the time delay exceed 0.250 second.
7. Each high-voltage neutral grounding resistor shall be provided with protection that will deenergize the longwall power center if the grounding resistor is subjected to a sustained ground-fault. This protection shall not be dependent upon control power and shall be either a thermal protection or a current transformer and overcurrent relay in the grounding resistor circuit that will deenergize the incoming high-voltage circuit supplying the power center.
8. Each high-voltage motor and shearer circuit shall be provided with instantaneous short-circuit protection set at not more than the setting specified in the longwall approval documentation or 75 percent of the minimum phase-to-phase short-circuit current available at the motor terminals, whichever is less. A time delay of not more than .050 second may be permitted for motors with high inrush currents. All components that provide short-circuit protection shall have sufficient interrupting rating to safely interrupt the maximum calculated available fault current.
9. Each high-voltage circuit supplying power from a longwall power center to a high-voltage starter enclosure shall be provided with short-circuit protection set at not more than 75 percent of the minimum available phase-to-phase short-circuit current at the high-voltage starter enclosure or the setting specified in the longwall approval documentation, whichever is less. A time delay may be permitted for coordination with downstream short-circuit protection devices. This time delay shall be set at the lowest practical value that permits reliable coordination; however, in no case shall the time delay exceed 0.250 second.
When two high-voltage cables are used to supply power to a common bus in the high-voltage starter enclosure and each cable has an overcurrent relay, each individual relay shall be set at appropriate values based on the number of relays.
10. The grounding circuit between each power center and a high-voltage starter enclosure shall be monitored by an MSHA-accepted system. When two or more high-voltage cables are used to supply power to the high-voltage starter enclosure, each cable shall be provided with ground-wire monitoring. The ground-wire monitoring circuits shall deenergize each cable when the grounding circuit or ground-check circuit becomes open. One circuit breaker shall be used in the power center to protect all cables connected to a common bus in the starter enclosure.
The cables shall be interlocked such that the circuit breaker will open when any cable is disconnected.
11. Each longwall power center and high-voltage starter enclosure shall be equipped with a primary visible disconnecting device installed to deenergize the primary of the high-voltage transformer or to deenergize high-voltage motor starters when the device is open. When the control and communication transformer is connected to the line side of the input disconnect, each longwall power center shall be provided with a visible disconnecting device installed to deenergize power to the longwall control and communication circuits when the device is open. The main disconnecting device may be two switches mechanically connected with one operating handle.
12. The control circuit for the high-voltage starter shall be interlocked with the input device such that:
a. When the input disconnecting device is in the open position, the control circuit can only be powered through an auxiliary switch in the test position; and
b. when the input disconnecting device is in the closed position, the control circuit can be powered only through an auxiliary switch in the normal position.
13. Each longwall power center or high-voltage starter shall be equipped with visible disconnecting device(s) and/or cable couplers installed to deenergize all high-voltage cables extending from their enclosure when the device is open.
14. Optional high-voltage disconnecting device(s) or cable couplers may be provided to deenergize the high-voltage cables that supply power to high-voltage components.
15. The high-voltage shearer may be provided with an optional shearer disconnecting device and/or cable couplers installed to deenergize the high-voltage motor contactor compartments located on the shearer.
16. Each disconnecting device shall be installed so that:
a. It can be determined by visual observation that the contacts are opened, when the device is in the open position, without removing any cover(s);
b. All load power conductors can be grounded when the device is in the "open" position;
c. The device can be locked in the "open" position; and
A sign shall be located near each disconnecting device identifying the circuit(s) the device disconnects.
17. Each high-voltage cable installed as part of the longwall mining system shall be type SHD-GC or other similar cable that meets the requirements of 30 CFR 75.804, with a minimum rating of 5,000 volts, and shall have an outer jacket that has been accepted by MSHA as flame-resistant.
18. Each splice or repair in a high-voltage cable shall be made in a workmanlike manner and in accordance with the instructions of the manufacturer of the splice or repair materials. The outer jacket of each splice or repair shall be vulcanized with flame-resistant material or made with a kit that has been accepted by MSHA as flame-resistant. Each splice or major repair shall be made so that all cable components are replaced with similar components. Repairs are considered major if there is any damage to the insulation, shielding, or conductors. Minor repairs to the cable jacket may be made by using tape accepted by MSHA as flame-resistant.
19. Splices and repairs in high-voltage power cables shall be made only by a qualified person (as provided in 30 CFR 75.153) who has received hands-on training in the proper methods of splicing and repairing high-voltage cables.
20. Cable handling and support systems (for example, Bretby and monorail systems) that are designed, installed, and maintained to protect the highvoltage cables from damage and to minimize the possibility of miners contacting the cables shall be used.
21. High-voltage cables shall be guarded at the following locations:
a. Where miners regularly work or travel over or under the cables;
b. Where the cables leave the cable handling and support systems to extend to electric components; and
c. Where the cables are in the same raceway as low- voltage cables.
The guarding shall protect the cables from damage and shall minimize the possibility of miners contacting the cables. The guarding shall be of grounded metal or reinforced non-conductive flame-resistant material.
22. High-voltage cables routed along the stageloader shall be protected by grounded metal barriers.
23. Energized high-voltage cables shall not be handled except when the shearer cable needs to be trained (shearer cable inadvertently coming out of the cable trough). When the shearer cable needs to be trained, high-voltage insulating gloves or high-voltage insulating sticks shall be used for protection against shock hazard. Miners shall not handle the shearer cable if the cable is out of the cable trough unless the cable has been deenergized. Miners shall not handle any other energized high-voltage cable.
24. High-voltage personal protective equipment, including rubber gloves, shall be visually inspected before each use. High-voltage rubber gloves shall be field air tested before each use to ensure their effectiveness. Damaged or defective protective equipment shall be removed from the mine or destroyed. A sufficient storage facility shall be provided for the cable handling equipment. The storage facility location shall be clearly marked to indicate its purpose and examined weekly to assure protective equipment is present. Insulated personal protective equipment shall be rated for a minimum of 7,500 volts and electrically tested every six months in accordance with a nationally recognized standard.
25. Barriers shall be provided and covers shall be arranged so that miners can work in the high-voltage section of the power center or starter enclosure without being exposed to energized high-voltage conductors or parts, including capacitors, when the appropriate onboard disconnect switch is in the "open" and "grounded" position.
26. Barriers shall be provided and covers shall be arranged so that miners can work in the control and communication compartments of the power center or starter enclosure without being exposed to energized conductors or parts that exceed 150 volts phase-to-ground regardless of the position of the appropriate onboard disconnect switch.
27. Barriers shall be provided and covers shall be arranged so that miners can work in the motor contactor compartments of the shearer without being exposed to energized high-voltage conductors or parts, when the shearer input disconnect switch is in the "open" and "grounded" position.
28. Cover interlock switches shall be provided to automatically deenergize the incoming high-voltage circuit to a unit of equipment, including the power center, when any cover that provides access to energized high-voltage conductors or parts is removed. However, motor junction boxes do not need cover interlock switches.
29. Caution labels shall be installed and maintained on the covers of the compartments of each longwall power center, starter enclosure, disconnecting device, optional shearer disconnect enclosure or shearer machine containing energized high-voltage circuits and parts to warn miners against entering these compartments before deenergizing the incoming power. An additional caution label shall be installed and maintained on the covers of the compartments that provide access to high-voltage capacitors to warn miners against entering these compartments before all high-voltage capacitors have been discharged. A means shall be available to ground these capacitors.
When low- or medium-voltage equipment can be energized with the input disconnect in the open position, caution labels shall be installed and maintained on the covers of the compartments to warn miners that the input disconnect only deenergizes high-voltage circuits.
30. Before any electrical work (including testing, troubleshooting and faultfinding) is performed inside the input high-voltage compartments of the longwall power center, starter enclosure, disconnecting device, optional shearer disconnecting device, shearer or motor contact enclosure a qualified person (as provided in 30 CFR 75.153) shall:
a. Determine that the contacts of the proper disconnecting device are "open" and "grounded" or when a cable coupler is used as a disconnecting device, determine that the high-voltage cable is deenergized and disconnected from the enclosure;
b. Lockout and tag the disconnect in this position;
c. If a cable coupler is used as the disconnecting device, connect the phase conductors in the high-voltage cable to a frame common to the enclosure by means of the grounding receptacle provided and place a dust cover on the enclosure receptacle from which the cable was disconnected; and
d. Insure that all high-voltage capacitors have been discharged and "grounded."
31. Before any electrical work (including testing, troubleshooting and faultfinding) is performed inside the high-voltage compartments of the longwall power centers a qualified person (as provided in 30 CFR 75.153) shall:
a. Determine that the contacts of the proper disconnecting device are "open" and "grounded";
b. Lockout and tag the disconnect in this position; and
c. Insure that all high-voltage capacitors have been discharged and "grounded."
32. Before any electrical work (including testing, trouble-shooting, or faultfinding) is performed on any high-voltage equipment or cable supplied from the starter enclosure, a qualified person (as provided in 30 CFR 75.153) shall:
a. Determine that the contacts of the proper disconnecting device are "open" and all affected conductors are "grounded" or when a cable coupler is used as a disconnecting device, determine that the high-voltage cable is deenergized and disconnected from the enclosure;
b. Lockout and tag the disconnect device in this position; and
c. If a cable coupler is used as the disconnecting device, connect the phase conductors in the high-voltage cable to a frame common to the enclosure by means of the grounding receptacle provided and place a dust cover on the enclosure receptacle from which the cable was disconnected.
33. The Petitioner's alternative method shall not be implemented until all electrical personnel who perform maintenance on the longwall have received training in high-voltage safety and maintenance procedures. Also, all personnel who work in proximity of the high-voltage equipment or who move high-voltage equipment or cables shall be trained in high-voltage safety procedures. A record of this training shall be maintained and made available to authorized MSHA representatives.
34. The high-voltage longwall mining equipment shall be MSHA approved.
35. The high-voltage longwall mining equipment shall not be put into service until after MSHA has inspected the equipment and determined that it is in compliance with all the above terms and conditions. The Petitioner shall notify MSHA before mining equipment is put into service in any subsequent longwall panel. The notice shall advise MSHA of any modifications to the equipment and provide a reasonable time for MSHA to schedule an inspection of the equipment if necessary.
36. Methane monitors shall be installed and maintained on the longwall face in accordance with 30 CFR 75.342.
37. A sufficient number of self-contained self-rescuers shall be stored in the vicinity of the headgate and the tailgate of the longwall section to meet the requirements of 30 CFR 75.1714.
38. Within 60 days after this Proposed Decision and Order becomes final, the Petitioner shall submit proposed revisions for its approved 30 CFR Part 48 training plan to the Coal Mine Safety and Health District Manager. These proposed revisions shall specify task training, including the terms and conditions stated in the Proposed Decision and Order.
Any party to this section desiring a hearing on this matter must file in accordance with 30 CFR 44.14, within 30 days. The request for hearing must be filed with the Administrator for Coal Mine Safety and Health, 4015 Wilson Boulevard, Arlington, Virginia 22203. If a hearing is requested, the request shall contain a concise summary of position on the issues of fact or law desired to be raised by the party requesting the hearing, including specific objections to the proposed decision. A party other than Petitioner who has requested a hearing shall also comment upon all issues of fact or law presented in the petition, and any party to this action requesting a hearing may indicate a desired hearing site. If no request for a hearing is filed within 30 days after service thereof, the Decision and Order will become final and must be posted by the operator on the mine bulletin board at the mine.
Robert A. Elam
Deputy Administrator
for Coal Mine Safety and Health