Petition for Modification
In the matter of
Mettiki Coal, LLC
Mettiki Mine
I.D. No. 18-00621
Docket No. M-2001-073-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 Mettiki Mine located in Garrett County, Maryland. The Petitioner alleges that the alternative method outlined in the petition will at all times guarantee no less than the same measure of protection afforded by the standard. The Petitioner is currently operating under an April 8, 1999 Proposed Decision and Order (PDO) which became final on May 10, 1999, (Docket No. M-1998-032-C), granting a modification of 75.1002, to permit the Mettiki Mine to operate face conveyor circuits at 2,400 volts. Under this petition, the Petitioner seeks to install a 2,400-volt shearer along with the high-voltage face conveyors.
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, comments and MSHA's investigative report and recommendation, this Proposed Decision and Order was issued. Once this PDO becomes final, and the high-voltage shearer with the high-voltage face conveyors are installed, inspected and approved by MSHA, it will supersede the PDO issued on April 8, 1999.
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 finding s of MSHA's investigation, Mettiki Coal, LLC is granted a modification of the application of 30 CFR 75.1002 to its Mettiki 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 Mettiki Coal, LLC's Petition for Modification of the application of 30 CFR 75.1002 in the Mettiki Mine is hereby:
GRANTED, for the 2,400-volt longwall equipment conditioned upon compliance with the following terms and conditions:
1. The nominal voltage of the longwall face conveyor circuits and the shearer circuit shall not exceed 2,400 volts. The nominal voltage of the remaining power circuits shall not exceed 995 volts.
2. The nominal voltage of the longwall control circuit shall not exceed 120 volts.
3. Ground-fault current for the 2,400-volt face conveyor circuits and the shearer circuit shall be limited by a neutral grounding resistor to not more than 1 ampere.
4. High-voltage circuits shall be protected against short-circuits, overloads, ground faults and undervoltage by a circuit interrupting device of adequate interrupting capacity.
5. 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.
6. The high-voltage circuits extending from the longwall power center to the longwall controller 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 not more than 0.125 ampere, whichever is less. Where two or more 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. 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.
7. The longwall power center shall be provided with backup ground-fault protection that shall de-energize 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.
8. The high-voltage neutral grounding resistor shall be provided with protection that will de-energize 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 be operated at either 50 percent of the maximum temperature rise of the resistor, or 150 degrees centigrade, whichever is less. The protection shall not be dependent upon control power and may consist of either a thermal protection or a current transformer and over-current relay in the grounding resistor circuit that will de-energize the incoming high-voltage circuit supplying the power center.
9. 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. The test circuit shall not subject the equipment to an actual phase-to-ground fault.
10. Each high-voltage motor and shearer circuit shall be provided with instantaneous short-circuit protection by means of vacuum circuit breaker 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 not to exceed 0.05 seconds (three cycles) may be used on solid state over current relays to allow startup of motors. All components that provide short-circuit protection shall have sufficient interrupting rating to safely interrupt the maximum calculated available fault current.
11. The 2,400-volt circuit(s) from the longwall power center to the high-voltage longwall starter enclosure 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 75 percent of the minimum available phase-to-phase short-circuit current at the longwall controller or the setting specified in the longwall approval documentation, whichever is less.Wheretwo or more high-voltage cables are used to supply power to a common bus in the high-voltage starter enclosure and each cable has a over current relay, each individual relay shall be set at appropriate values based on the number of relays. A time delay may be permitted for coordination with downstream short-circuit protection devices. The time delay shall in no case exceed 0.25 seconds.
12. Where two or more high-voltage cables are used to supply power to a common bus in the longwall starter enclosure, each cable shall be provided with an MSHA accepted ground-wire monitoring system. The ground-wire monitoring circuits shall de-energize each cable when either the grounding circuit or ground-wire monitoring circuit of either cable becomes severed or 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.
13. The longwall power center shall be equipped with a primary visible disconnecting device installed to de-energize the primary of the high-voltage transformer(s) when the device is open. A visible disconnect shall also be provided for control and communications circuits.
14. The longwall power center shall be equipped with a secondary (2,400-volt) disconnecting device installed to de-energize all high-voltage cables extending to the longwall starter enclosure when the device is open.
15. The longwall starter enclosure shall be provided with a main visible disconnecting device installed to de-energize all high-voltage power conductors extending from the enclosure.
16. The high-voltage shearer shall be provided with a disconnecting device installed to de-energize and ground the high-voltage motor contactor compartments located on the shearer. Any optional high-voltage disconnect device on other equipment shall be provided with disconnecting devices installed to de-energize and ground the high-voltage cables extending to the high-voltage components.
17. 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;
c. The disconnecting device can be locked in the "open" position; 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.
e. A sign shall be located near the disconnecting device identifying the circuit(s) the device disconnects.
18. Each 2,400-volt 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.
19. If any metallic component of a high-voltage cable is damaged, the cable shall be de-energized and repaired. 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 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 accepted by MSHA as flame-resistant.
20. 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 high-voltage cables.
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.
d. 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 installed in belt conveyor entries during cleanup, and conveyor belt or belt structure removal if the cables are within 12 inches of mobile equipment, unless the cables are de-energized.
22. 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.
23. Adequate means to secure any connection box or in-line connector used at mid-face shall be installed to provide secure connections of the high-voltage cable.
24. 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 de-energized. Miners shall not handle any other energized high-voltage cable.
25. 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.
26. 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 conductors or parts that exceed nominal 150 volts RMS, including capacitors, when the primary disconnect switch is in the "open" and "grounded" position.
27. Barriers shall be provided and covers shall be arranged so that miners can work in the control and communication compartment(s) of the power center without being exposed to energized conductors or parts that exceed nominal 150 volts RMS regardless of the position of the primary disconnect switch.
28. Barriers shall be provided and covers shall be arranged so that miners can work in the motor contactor compartments of the longwall controller without being exposed to energized high-voltage conductors or parts that exceed nominal 150 volts RMS when the main disconnect switch is in the "open" and "grounded" position.
29. Barriers shall be provided and covers shall be arranged so that miners can work in the longwall communication and control compartments of the high-voltage longwall starter enclosure without being exposed to energized conductors or parts that exceed nominal 150 volts RMS regardless of the position of the main disconnect.
30. Barriers shall be provided and covers shall be arranged so that miners can work in the motor contactor compartments of the high-voltage shearer without being exposed to energized conductors or parts that exceed nominal 150 volts RMS when the shearer disconnect switch is in the "open" and "grounded" position.
31. Cover interlock switches shall be provided to automatically de-energize the incoming high-voltage circuit to the power center, when any cover that provides access to energized high-voltage conductors or parts, including capacitors, is removed.
32. Cover interlock switches shall be provided and wired to automatically de-energize the 2,400 volt circuit supplying power to the longwall starter enclosure, when any cover that provides access to energized 2,400 volt conductors or parts is removed. This condition does not apply to covers installed on motor junction boxes.
33. Cover interlock switches shall be provided and wired to automatically de-energize the shearer or any optional disconnecting device, when any cover that provides access to energized 2,400 volt conductors or parts is removed. This condition does not apply to covers installed on motor junction boxes.
34. 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.
35. The control circuits for high-voltage and other circuits in the longwall controller 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), and
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.
36. Caution labels shall be installed and maintained on the covers of the compartments of each longwall power center, controller enclosure, shearer, or optional disconnect enclosure(s) containing a disconnecting device. The caution labels shall warn miners against entering these compartments before deenergizing the incoming power. Also, caution labels shall be installed and maintained on all covers that provide access to 2,400-volt conductors and parts to warn miners against entering these compartments before all 2,400-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.
37. Before any electrical work (including testing, troubleshooting and faultfinding) is performed inside the input high-voltage compartments or 2,400 volt compartments of a power center, 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";
b. Lockout and tag the disconnecting device; and
c. Assure that capacitors have been discharged and "grounded".
38. Before any electrical work (including testing, troubleshooting, and faultfinding) is performed inside any high-voltage compartment of the starter enclosure or on the high-voltage cables supplying the controller, a qualified person (as provided in 30 CFR 75.153) shall:
a. Determine, at the power center, that the contacts of the secondary disconnecting device are "open" and "grounded";
b. Lockout and tag the disconnecting device;
c. Assure that all 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.
39. Before any electrical work (including testing, trouble-shooting, or faultfinding) is performed inside the contactor compartments for the controller enclosure, a qualified person (as provided in 30 CFR 75.153) shall:
a. Determine that the contacts of the main disconnecting device in the controller are "open" and "grounded";
b. Lockout and tag the disconnect device in this position;
c. Assure that all 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.
40. Before any electrical work (including testing, trouble-shooting, or faultfinding) is performed on any high-voltage equipment or cable supplied from the longwall starter enclosure, a qualified person (as provided in 30 CFR 75.153) shall:
a. Determine that the contacts of the appropriate disconnecting device for the circuit are "open" and "grounded";
b. Lockout and tag the disconnect device in this position; and
c. 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.
41. 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 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.
42. The high-voltage longwall mining equipment shall be MSHA approved.
43. 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.
44. Methane monitors shall be installed and maintained on the longwall face in accordance with 30 CFR 75.342.
45. 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