In the matter of Petition for Modification
West Ridge Resources, Inc.
West Ridge Mine
I.D. No. 42-02233 Docket No. M-1999-053-C
PROPOSED DECISION AND ORDER
On June 3, 1999, a petition was filed seeking a modification of the application of 30 CFR 75.1002-1(a) to Petitioner's West Ridge Mine located in Carbon County, Utah. 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, MSHA's investigative report and recommendations, this Proposed Decision and Order (PDO) 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 75.1002-1(a).
On the basis of the petition and the findings of MSHA's investigation, West Ridge Resources, Inc., is granted a modification of the application of 30 CFR 75.1002-1(a) to its West Ridge 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 West Ridge Resources, Inc.'s Petition for Modification of the application of 30 CFR 75.1002-1(a) in the West Ridge Mine is hereby:
GRANTED, for the 2,400-volt longwall system, conditioned upon compliance with the following terms and conditions:
1. The nominal voltage of the longwall power circuit(s) 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 of 0.5 amperes. Current transformers used for the ground-fault protection shall be the single-window type and shall be installed to encircle all three-phase conductors.
4. Each high-voltage motor 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 not more than
0.125 ampere, whichever is less.
5. The longwall power center 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 not more than 0.125 ampere, whichever is less. A time delay may be permitted for coordination with the 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 0.25 seconds.
6. The longwall power center shall be provided with backup ground-fault protection that shall deenergize the 2,400-volt circuit breaker 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 0.25 seconds.
7. The 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. The protection shall not be dependent upon control power and may consist of 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 2,400-volt high-voltage motor circuit shall be provided with instantaneous short-circuit protection by means of an automatic high-voltage circuit interrupting device 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. All components that provide short-circuit protection shall have sufficient interrupting rating to safely interrupt the maximum calculated available fault current.
9. The 2,400-volt circuit(s) supply power from the longwall power center to the high-voltage longwall controller shall be provided with short-circuit protection by means of an automatic high-voltage circuit interrupting device in the longwall power center. This circuit interrupting device shall be set at not more than 75 percent of the minimum available phase-to-phase short-circuit current at the high-voltage longwall controller 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. The time delay shall not exceed the setting specified in the approval documentation, or 0.25 seconds, whichever is less.
10. Each ground-fault current device shall be provided with a test circuit to test the device at 50 percent or less of the current rating of the grounding resistor and the test circuit shall cause the corresponding circuit interrupting device to open. Each ground-fault device shall be driven by a single window current transformer, which shall encircle the load power conductors of each circuit. The test circuit shall not subject the equipment to an actual phase-to-ground fault.
11. The longwall power center shall be equipped with a primary visible disconnecting device installed to deenergize the primary of the high-voltage transformer(s) when the device is open.
12. The longwall power center shall be equipped with a secondary (2,400-volt) disconnecting device installed to deenergize all high-voltage power conductors extending to the longwall controller when the device is open.
13. The longwall controller shall be provided with a main visible disconnecting device installed to deenergize all high-voltage power conductors extending from the longwall controller.
14. Each disconnecting device shall be installed so that:
(a) It can be determined by visual observation that the contacts are opened without removing any cover(s);
(b) All high-voltage load power conductors can be grounded when the disconnecting device is in the "open" position; and
(c) The disconnecting device can be locked in the "open" position.
A sign shall be located near the disconnecting device identifying the circuit(s) the device disconnects.
15. 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. This condition is not applicable if a separate 101 (c) petition for modification for the use of other cable designs has been granted by MSHA.
16. 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 cold pour compound 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 shielding,, grounding conductors, ground-check circuit conductors, inner conductor insulation or load power conductors. Minor repairs to the cable jacket may be made by using tape that has a voltage rating that is equal to the voltage rating of the outer jacket of the cable and is accepted by MSHA as flame-resistant.
17. 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.
18. High-voltage cables shall be guarded at the following locations:
(a) Where miners regularly work or travel over or under the cables less than 6-1/2 feet above the mine floor;
(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. Additional guarding shall be provided on high-voltage cables in belt conveyor entries during cleanup and belt structure removal if the cables are within 12 inches of mobile equipment, unless the cable is deenergized.
19. Cable handling and support systems (for example, Bretby and monorail systems) that are designed, installed, and maintained to protect the 2,400-volt cables from damage, and to minimize the possibility of miners contacting the cables shall be used.
20. Adequate means to secure the connection box or in-line connector at the middle of the face, when used, shall be installed to provide secure connection of the high- voltage cables.
21. Energized high-voltage cables shall not be handled except when the motor or shearer cable need to be trained (shearer cable inadvertently coming out of the cable trough). When the motor or 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 motor or shearer cable if the cable is out of the cable trough, unless the cable has been deenergized or the miner uses high-voltage gloves or a high- voltage insulating stick. Miners shall not handle any other energized high-voltage cable.
22. High-voltage personal protective equipment, including the outer protective leather and inner 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 storage facility shall be provided for the protective cable handling equipment. The storage facility location shall be clearly marked to indicate its purpose and examined weekly to ensure personal protective equipment is present. Insulated personal protective shall be rated for a minimum of 7,500 volts and electrically tested every six months in accordance with a nationally recognized standard.
23. Barriers shall be provided and covers shall be arranged so that miners can work in the high voltage section of the power center without being exposed to energized high-voltage conductors or parts, including capacitors, when the primary disconnecting device is in the "open" and "grounded" position.
24. Barriers shall be provided and covers shall be arranged so that miners can work in the control and communication compartment(s) of the longwall controller without being exposed to energized high- voltage conductors or parts regardless of the position of the primary disconnecting device.
25. Barriers shall be provided and covers shall be arranged so that miners can work in the vacuum contactor compartments of the longwall controller without being exposed to any energized high-voltage conductors or parts when the secondary 2,400-volt disconnecting device is in the "open" and "grounded" position.
26. Cover interlock switches shall be provided to automatically deenergize the incoming high-voltage circuit to the power center when a cover that provides access to energized high-voltage conductors or parts, including capacitors, is removed.
27. Cover interlock switches shall be provided and wired to automatically deenergize the 2,400-volt circuit supplying power to the longwall controller when a cover that provides access to energized high- voltage conductors or parts is removed. This condition does not apply to covers installed on motor junction boxes.
28. The control circuit for the power center shall be interlocked with the primary disconnecting device in the power center so that:
(a) When the primary 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 primary disconnecting device is in the "closed" position, the control circuit can be powered only through an auxiliary switch in the "normal" position.
29. Caution labels shall be installed and maintained on the covers of the compartments of each longwall power center, controller enclosure and shearer enclosure. The caution labels shall warn miners to deenergize and ground the high-voltage circuit supplying power to the compartment before entering the compartment. Also, caution labels shall be installed and maintained on all covers of the compartments providing access to high- voltage conductors and parts to warn miners against entering these compartments before all capacitors have been discharged. A means shall be available to ground the capacitors.
When low- or medium-voltage equipment or circuits can be energized with the input disconnecting device in the open position, caution labels shall be installed and maintained on the covers of the compartments to warn miners that the appropriate disconnecting device deenergizes only the high-voltage power circuit(s).
30. Before any electrical work (including testing, troubleshooting and faultfinding) is performed on any high-voltage equipment, circuit or cable a qualified person (as provided in 30 CFR 75.153) shall:
(a) Determine that the contacts of the appropriate disconnecting device are "open" and "grounded". When a cable coupler is used as a disconnecting device, determine that the high-voltage cable is deenergized and disconnected from the power source;
(b) Lockout and tag the disconnecting device or cable coupler in this position;
(c) Assure that capacitors have been discharged and "grounded"; and
(d) If a cable coupler is used as the disconnecting device, connect the load power conductors in the high-voltage cable to the grounded frame of the enclosure by means of the grounding receptacle provided and place a dust cover on the enclosure receptacle from which the cable was disconnected.
31. The Petitioner's alternative method shall not be implemented until all 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 cables 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 and to other interested parties.
32. The high-voltage longwall mining equipment shall be MSHA approved.
33. 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.
34. Methane monitors shall be installed and maintained on the longwall face in accordance with 30 CFR 75.342.
35. A minimum of 12 self-contained self-rescuers (SCSR's) shall be stored in the vicinity of the headgate and a minimum of 12 SCSRs shall be stored along the longwall face or at the tailgate of the longwall section to meet the requirements of 30 CFR 75.1714.
36. 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 initial and refresher training regarding 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.
Michael J. Lawless
Deputy Administrator
for Coal Mine Safety and Health