On August 19, 1996, a petition was filed seeking to amend item No. 24 of the modification of 30 CFR 75.1002 granted on October 13, 1995 (Docket No. M-95-029-C) to petition's Maple Creek Mine, located in Bentlyville, Washington County, Pennsylvania. 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.
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 this Proposed Decision and Order (PDO) is issued. Once it becomes final, it shall supersede the modification of 75.1002 granted in Docket No. M-95-029-C.
The alternative method proposed by the Petitioner will at all times guarantee no less than the same 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, Maple Creek Mining, Incorporated is granted a modification of the application of 30 CFR 75.1002 to its Maple Creek Mine.
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 1077, 30 U.S.C., sec. 811(c), it is ordered that Maple Creek Mining, Incorporated’s Petition for Modification of the application of 30 CFR 75.1002 in the Maple Creek Mine is hereby:
GRANTED, for the high-voltage equipment located in the Maple Creek Mine, conditioned upon compliance with the following terms and conditions:
1. The nominal voltage of the longwall power circuit(s) for the face conveyor motors 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 4,160-volt circuits shall be limited by a neutral grounding resistor to not more than 3.75 amperes.
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 0.100 ampere, whichever is less.
5. The longwall power center shall be provided with backup ground-fault protection that shall deenergize the 4,160-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.
6. The high-voltage neutral grounding resistor shall be provided with overtemperature protection that will deenergize the longwall power center if the grounding resistor is subjected to a sustained ground-fault. The overtemperature 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.
7. Each high-voltage motor 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. All components that provide short-circuit protection shall have sufficient interruption rating to safely interrupt the maximum calculated available fault current.
8. The 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.
9. Each disconnect device shall be installed as follows so that:
(a) It can be determined by visual observation that the contacts are opened without removing any cover(s);
(b) All load power conductors can be grounded when the device is in the "open" position; and
(c) The device can be locked in the "open" position.
A sign shall be located near the switch identifying the circuit(s) the device disconnects.
10. Each 4,160-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.
11. Each splice or repair in 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. Kits having tape as the outer jacket are not acceptable.
12. The 4,160-volt cables shall be guarded at the following locations:
(a) Where miners regularly work or travel over or under the cables; and
(b) Any place where the cables leave the cable handling and support systems to extend to electric components.
The guarding shall protect the cables from damage and shall minimize miners' contact with 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 cleanup and belt structure removal if the cables are within 12 inches of mobile equipment, unless deenergized.
13. 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.
14. Cable handling and support systems (for example, Bretby and monorail systems) that are designed, installed, and maintained to protect the 4,160-volt cables from damage and to minimize the possibility of miners contacting the cables shall be used.
15. Barriers shall be provided and covers shall be arranged so that miners can work in the 4,160-volt section of the power center without being exposed to energized 4,160-volt conductors or parts, including capacitors, when the primary disconnect switch is in the "open" and "grounded" position.
16. Barriers shall be provided and covers shall be arranged so that miners can work in the control compartment of the power center without being exposed to energized high-voltage conductors or parts regardless of the position of the primary disconnect switch.
17. Cover interlock switches shall be provided to automatically deenergize the high-voltage circuit supplying the longwall power center when any cover of the power center that provides access to energized high-voltage conductors or parts is removed.
18. 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 main disconnecting device is in the "closed" position, the control circuit can be powered only through an auxiliary switch in the "normal" position.
19. Caution labels shall be installed and maintained on the covers of the compartments of the longwall power center containing the primary disconnect device to warn miners against entering these compartments before deenergizing the incoming power to the power center. 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 and grounded.
20. Before any electrical work (including testing, troubleshooting, and fault-finding) is performed inside any compartment of the power center containing 4,160 volts, a qualified person (as provided in 30 CFR 75.153) shall:
(a) Determine that the contacts of the primary disconnect device in the power center are "open" and grounded;
(b) Lockout and tag the disconnect device; and
(c) Assure that all 4,160 volt capacitors have been discharged and grounded.
21. The Petitioner's alternative method shall not be implemented until all personnel who perform maintenance on the longwall or miners who work in proximity of the high-voltage equipment have received training in high-voltage safety and maintenance procedures. Also, all personnel 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 representatives and to other interested parties.
22. The high-voltage longwall mining equipment shall be MSHA approved.
23. A methane monitor shall be installed and maintained on the longwall face in accordance with the requirements of 30 CFR 75.342.
24. The maximum width of longwall panels shall not exceed 1000 feet and maximum length shall not exceed 14,000 feet.
25. A minimum of 12 self-contained self-rescuers (SCSR's) shall be stored in the vicinity of the headgate and a minimum of 12 SCSR's shall be stored along the longwall face or at the tailgate of the longwall section. This provision will remain in effect until miners are provided with belt wearable SCSR's which can be worn, carried, or kept within 25 feet of their person.
26. 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.
27. A travelway shall be maintained on the tailgate side of the longwall panel. If the travelway becomes impassible, management shall notify MSHA and the representative of the miners, and the tailgate blockage plan, approved by MSHA under 30 CFR 75.222 (g) (2) shall be put into effect. (The tailgate travelway shall be maintained to ensure passage at all times of any person, including a disabled person, subject to the utilization of the tailgate blockage plan). The travelway shall be ventilated by intake air to the extent possible, as long as it does not disrupt the ventilation system.
28. A primary escapeway maintained in accordance with 30 CFR 75.380 shall be provided on the headgate end of all longwall panels. Equipment shall not be permitted in the entry except under emergency circumstances and/or for maintenance of the entries. In addition, equipment necessary to transport miners and/or materials may be used in the primary escapeway from the face outby for a distance of 1,000 feet.
29. Systematic supplemental roof support, as set out in the Roof Control Plan approved by MSHA, shall be installed as follows:
(a) In the tailgate of the first panel adjacent to a barrier the roof supports shall be maintained a minimum of 500 feet outby the retreating longwall face.
(b) In the proposed tailgate entry of each subsequent panel the roof supports shall be maintained in advance of the frontal abutment stress, but not less than 50 feet outby the retreating longwall face. This does not preclude installation of additional roof supports, should conditions in the entry so dictate.
30. Sufficient rock dust shall be applied throughout the panel to be in compliance with 30 CFR 75.403, and to adequately control float coal dust. A rock duster shall be positioned in order to adequately or continuously rock dust the return entry while the shearer is operating. Should the rock duster become inoperable, repairs shall be initiated immediately and other alternate methods may be used to control float dust until the repairs are completed. These alternate methods shall be initiated immediately and shall be used for no more than an 8 hour period. If at the end of this 8 hour period the primary rock dusting system is not operable, cutting coal shall cease.
31. Respirable dust samples shall be taken as described in 30 CFR 70.207. If the results of those samples exceed the applicable standard in 30 CFR 70.100 or 70.101, Maple Creek Mining, Inc., shall take the necessary corrective measures to bring the designated occupation back into compliance. No one shall be permitted inby the tail drum of the shearer during the longwall mining operations until corrective measures are in place.
32. 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 action desiring a hearing on this matter must file in accordance with 30 CFR 44.14, within 30 days, a request 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.
Item No. 24 - The maximum width of longwall panels shall not exceed 1,000 feet and maximum length shall not exceed 14,000 feet.
_________________________________
Robert A. Elam
Deputy Administrator
for Coal Mine Safety and Health
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