Petition for Modification
In the matter of
American Energy Corporation
Century Mine
I.D. No. 33-01070
Docket No. M-2001-072-C
30 CFR 75.1002
PROPOSED DECISION AND ORDER
On June 21, 2001, a petition was filed seeking a modification of the application of 30 CFR 75.1002 to Petitioner's Century Mine, located in Belmont County, Ohio. 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.
On the basis of the petition and the findings of MSHA's investigation, American Energy Corporation, is granted a modification of the application of 30 CFR 75.1002 to its Century 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 American Energy Corporation's Petition for Modification of the application of 30 CFR 75.1002 in the Century Mine is hereby:
GRANTED, for the 4,160-volt longwall located at the Century Mine, conditioned upon compliance with the following terms and conditions:
1. The nominal voltage of the longwall power circuits shall not exceed 4,160 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 0.50 amperes or less.
4. High-voltage circuits shall be protected against short-circuits, overloads, ground faults, and under-voltage by a circuit interrupting device of adequate interrupting capacity.
5. Circuit interrupting devices shall not reclose automatically.
6. 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 not more than 0.125 ampere, whichever is less.
7. The circuits to the high-voltage starters 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. Where two or more high-voltage cables are used to supply power to a common bus in a separate starter enclosure and each cable has a ground-fault relay, each ground-fault relay shall be set at an appropriate value determined by the number of relays used. 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 second.
8. The longwall power center shall be provided with backup ground-fault protection that shall deenergize the main 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 second.
9. Each voltage neutral grounding resistor shall be provided with thermal protection that will deenergize the longwall power center if the grounding resistor is subjected to a sustained ground-fault. The thermal protection shall not be dependent upon control power and shall operate at either 50 percent of the maximum temperature rise of the grounding resistor, or 150 degrees centigrade, whichever is less. The thermal protection may consist of a current transformer and overcurrent relay in the grounding resistor circuit that will deenergize the power center.
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 current 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. 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 three cycles (0.050 seconds) 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.
12. The 4,160 volt circuit(s) to the high-voltage starters shall be provided with short circuit protection by means of a high-voltage circuit breaker in the longwall power center. This circuit breaker shall be 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 at the starters, whichever is less.
13. Where two or more high-voltage cables are used to supply power to a common bus in a separate starter enclosure and each cable has an overcurrent relay, each overcurrent relay shall be set at an appropriate value determined by the number of relays used. A time delay may be permitted for coordination with the downstream overcurrent protection devices. The time delay shall not exceed the setting specified in the approval documentation, or 0.25 second, whichever is less.
14. The grounding circuit between each power center and a high-voltage longwall controller shall be monitored by a MSHA-accepted ground-wire monitoring system. Where two or more high-voltage cables are used to supply power to a common bus in a separate starter enclosure, each cable shall be provided with ground-wire monitoring. The ground-wire monitoring circuits shall deenergize each cable when the grounding conductor(s) of any cable becomes severed or open. One circuit breaker shall be used in the power center to protect all cables or each cable may be protected by an individual circuit breaker. The cables shall be interlocked such that the circuit breaker(s) will open when any cable is disconnected.
15. Each longwall power center shall be equipped with a primary visible disconnecting device installed to deenergize the primary of the high voltage transformer when the device is open. A visible disconnect will also be provided for the control and communication circuits.
16. Each longwall power center shall be provided with secondary (4,160-volt) disconnecting devices and/or cable couplers installed to deenergize all high voltage cables when the device is open.
17. When a separate starter enclosure is used, the starter enclosure shall be provided with a main visible disconnecting device installed to deenergize all high-voltage power conductors extending from the enclosure when the device is open. A visible disconnect will also be provided for the control and communication circuits.
18. Optional high-voltage disconnect enclosures shall be provided with disconnecting devices installed to deenergize the 4,160 volt cables extending from the enclosures.
19. The high voltage shearer may be provided with an optional shearer disconnecting device installed to deenergize the 4,160 volt motor contactor compartments located on the shearer.
20. 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 device is in the "open" position;
c. The device can be locked in the "open" position.
d. If a cable coupler is used as the visible disconnecting device, connect the phase conductors in the high-voltage trailing cable to the grounded section power center frame by means of the grounding receptacle provided and place a dust cover on the enclosure receptacle from which the cable was disconnected.
e Disconnecting devices, except cable couplers and devices installed in explosion-proof enclosures, shall be capable of interrupting the full-load current of the circuit or designed and installed to cause the current to be interrupted automatically prior to the opening of the contacts of the device. Disconnecting devices installed in explosion-proof enclosures shall be maintained in accordance with the approval documentation.
For the purpose of testing, troubleshooting or fault finding, the deenergized high-voltage cable can be disconnected from the provided grounding receptacle only for that period of time necessary to locate and determine the defective condition. The high-voltage cable shall be reconnected to the grounding receptacle prior to work being performed to correct the defective condition.
A sign shall be located near the disconnecting device identifying the circuit(s) the device disconnects.
21. Each high-voltage cable installed as part of the longwall mining system shall be type SHD-GC or other similar cable that meet 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.
22. 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 using tape accepted by MSHA as flame resisitant. Splice kits employing tape as an outer jacket are not acceptable.
23. Splices and repairs in high-voltage 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 these high-voltage cables.
24. Cable handling and support systems (for example, Bretby and monorail systems) that are designed, installed, and maintained to protect the high-voltage cables from damage and to minimize the possibility of miners contacting the cables shall be used.
25. 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. Additionally, guarding shall be provided on high-voltage cables in belt conveyor entries during clean-up and belt structure removal if the cables are within 12 inches of mobile equipment, unless deenergized.
26. Adequate means to secure the connection box or in-line connector at the middle of the face shall be installed to provide secure connections of the high-voltage cables.
27. High-voltage cables routed along the stage loader shall be portected by grounded metal troughing.
28. 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 hazards. 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.
29. 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.
30. Barriers shall be provided and covers shall be arranged so that miners can work in the 4,160 volt section of each power center or high-voltage starter enclosure without being exposed to either energized conductors or parts that exceed 150 volts RMS, including capacitors, when the appropriate onboard disconnect switch is in the "open" and "grounded" position.
31. Barriers shall be provided and covers shall be arranged so that miners can work in the control and communication compartments of each power center or high-voltage starter enclosure without being exposed to energized conductors or parts that exceed 150 volts RMS regardless of the position of the primary disconnect switch. However, the capacitance tripping circuits may remain energized
32. 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 conductors or parts that exceed 150 volts-to-ground, including capacitors, when the onboard shearer disconnect switch is in the "open" and "grounded" position.
33. Cover interlock switches shall be provided to automatically deenergize the incoming high-voltage circuit to a power center, starter enclosure, junction box, or optional disconnect switch 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.
34. Cover interlock switches should be provided to automatically deenergize the incoming high-voltage circuit to the shearer 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.
35. The control circuit for each 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.
36. The control circuits for high-voltage and other circuits in the starter enclosure shall be interlocked with the main disconnecting device so that:
a. When the main disconnecting device is in the "open" position, the control circuit can only be powered through an auxiliary control switch in the "test" position, (in the test position, no voltage greater than 120-volts nominal shall exit the controller);
b. When the main disconnecting device is in the "closed" position, the control circuit can be powered only through an auxiliary control switch in the "normal" position; and
c. The control circuit shall be interlocked with the main disconnecting device so that attempting to close the main disconnecting device while in the "test" position shall cause the incoming 4,160 volt to be deenergized.
37. Caution labels shall be installed and maintained on the covers of the compartments of each longwall power center, starter enclosure, or optional shearer disconnect enclosure containing a primary disconnecting device, to warn miners against entering these compartments before deenergizing and grounding the incoming power. Also, caution labels shall be installed and maintained on all covers that provide access to 4,160 volt conductors and parts to warn miners against entering these compartments before all 4,160 volt 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.
38. Caution labels shall be installed and maintained on the covers of the compartment of the shearer containing an onboard shearer disconnecting device to warn miners against entering this compartment before deenergizing the incoming power to the shearer. Also, caution labels shall be installed and maintained on all covers that provide access to 4,160 volt conductors and parts to warn miners against entering these compartments before opening the shearer disconnect on the shearer.
39. Caution labels should be installed and maintained on the covers of all other high-voltage enclosures located on the longwall mining system to warn miners against entering high-voltage compartments before deenergizing the incoming power.
40. Before any electrical work (including testing, trouble-shooting and fault finding) is performed inside the input high-voltage compartments of the power center or starter enclosure, a qualified person (as provided in 30 CFR 75.153) shall:
a. Determine that the contacts of an outby disconnect are "open" and "grounded";
b. Lockout and tag the disconnect; and
c. Assure that capacitors have been discharged and "grounded."
41. Before any electrical work (including testing, trouble-shooting, and faultfinding) is performed inside any compartment of the power center, longwall enclosure, or shearer containing 4,160 volts, a qualified person (as provided in 30 CFR 75.153) shall:
a. Determine that the contacts of the appropriate disconnect device are "open" and "grounded";
b. Lockout and tag the disconnecting device, and
c. Assure that all 4,160 volt capacitors have been discharged and "grounded".
Also, each ungrounded conductor or the high-voltage circuit or cable upon which work is to be performed shall be connected to the system grounding medium.
42. Before any electrical work(including testing, trouble-shooting, and faultfinding) is performed on any high-voltage equipment or cable supplied from the longwall controller, 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 for the enclosure;
b. Lockout and tag the disconnecting device in this position; and
c. If a cable coupler is used as the usual 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 receptacle from which the cable was disconnected.
43. Prior to implementing this alternative method, all personnel who perform maintenance on longwall shall receive 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 and to other interested parties.
44. The high-voltage longwall mining equipment shall be MSHA approved.
45. 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 panel. The notice shall advise MSHA of any modifications to the equipment and provide a reasonable time for MSHA to schedule and inspection of the equipment if necessary.
46. Methane monitors shall be installed and maintained on the longwall face in accordance with 30 CFR 75.342.
47. 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.
48. Within 60 days after the 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