| In the matter of Twenty Mile Coal Company Foidel Creek Mine I.D. No. 05-03836 | Petition for Modification Docket No. M-1998-056-C |
On May 18, 1998, a petition was filed seeking a modification of the application of 30 CFR 75.901(a) to Petitioner's Foidel Creek Mine, located in Routt County, Colorado. 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 75.901(a).
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 recommendations, this Proposed Decision and Order is issued.
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 75.901(a).
On the basis of the petition and the findings of MSHA's investigation, Twenty Mile Coal Company is granted a modification of the application of 30 CFR 75.901(a) in the Foidel 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 1977, 30 U.S.C., sec. 811(c), it is ordered that Twenty Mile Coal Company's Petition for Modification of the application of 30 CFR 75.901(a) to the Foidel Creek Mine is hereby:
- GRANTED, for the 480-volt, three-phase, 320KW/400KVA Diesel Powered Generator (DPG) set supplying power to a three-phase transformer and three-phase 480-volt, and 995-volt power circuits, conditioned upon compliance with the following terms and conditions:
- 1. The 320KW, 480-volt, diesel powered generator set with an approved diesel drive engine shall only be used to move equipment in and out of the mine and to perform rehab work in areas outby section loading points.
- 2. The sum of all motors operated from the diesel powered generator system at one time shall not exceed 275 horsepower.
- 3. The neutral of the secondary side of the wye configured 480-volt transformer shall have in series between it and the frame of the generator unit, a 480-volt rated resistor that will limit phase-to-frame fault current to 0.5 ampere continuously and is insulated from ground equal to the phase-to-phase voltage of the system.
- 4. The direct or derived neutral of the 995-volt secondary side of the step-up transformer shall have in series between it and the frame of the generator unit, a 995- volt rated resistor that will limit phase-to-frame fault current to 0.5 ampere continuously and is insulated from ground equal to the phase-to-phase voltage of the system.
- 5. The 480-volt output circuit of the alternator shall be equipped with a sensitive ground fault relay set to cause the circuit breaker that supplies power to the primary of the 480-volt transformer to trip and shut down the diesel engine when a phase-to-frame fault not to exceed 90 milliamperes occurs.
- 6. The secondary transformer 480-volt, and 995-volt circuits shall each be equipped with a sensitive ground fault relay that will cause their respective circuit breaker(s) to trip and shut down the diesel engine when a phase-to-frame fault not to exceed 90 milliamperes occurs.
- 7. The 995-volt circuit breaker shall be provided with a means to provide short-circuit, overcurrent, grounded-phase, undervoltage and ground monitoring protection. The protection for the 995-volt portable equipment cables shall be provided by a 225 or 400 maximum ampere rating circuit breaker, that is equipped with the instantaneous only trip unit (settings for the instantaneous only trip unit shall be limited to between 500 and 1000 amperes) that provides the specified protection for the portable cable attached to the circuit breaker. The instantaneous only trip unit for the 995-volt circuit breaker shall be adjusted to trip at 70 percent of the minimum available short circuit current at the point where the portable cable enters the equipment or the maximum allowable instantaneous settings specified in 30 CFR §75.601-1, whichever is less.
- 8. The 480-volt circuit breaker shall be provided with a means to provide short-circuit, overcurrent, grounded-phase, undervoltage and ground monitoring protection. The protection for the 480-volt portable equipment cables shall be provided by a 225 or 400 maximum ampere rating circuit breaker, that is equipped with an instantaneous only trip unit (settings for the instantaneous only trip unit shall be limited to between 500 and 1500 amperes). The instantaneous only trip unit for the 480-volt circuit breaker shall be adjusted to trip at 70 percent of the minimum available short circuit current at the point where the portable cable enters the equipment or the maximum allowable instantaneous settings specified in 30 CFR 75.601-1, whichever is less.
- 9. When the generator set is used to move equipment or perform work in areas outby the section loading point where equipment is not required to be maintained permissible, the equipment portable cable length(s) shall not exceed the length(s) specified in 30 CFR Part 18, Table 9.
- 10. Permanent label(s)showing the maximum circuit breaker setting(s) and maximum portable cable length(s) shall be installed on each instantaneous trip unit or be maintained near each 480-volt, and 995-volt circuit breaker. The permanent label(s) shall be maintained legible.
- 11. When the generator set is used to move equipment or perform work in areas outby the section loading point where equipment is not required to be maintained permissible, the grounding system shall include a MSHA accepted ground wire monitor system, or other no less effective device approved by the District Manager to assure ground continuity between the frame of the generator and the equipment being moved or used.
- 12. The 995-volt portable cable(s) that extend from the generator to mobile equipment shall be type SHD-GC with a minimum of 2,000-volt rating, and shall have an outer jacket that has been accepted by MSHA as flame-resistant. All other portable cables used to supply power to 480-volt equipment shall have a minimum of 2,000-volt rating and shall have an outer jacket that has been accepted by MSHA as flame-resistant.
- 13. A strain relief shall be provided on each end of the cable(s) that extends between the generator and the piece of mobile equipment being powered.
- 14. Prior to moving each piece of equipment or performing work in areas outby the section loading point where the equipment is not required to be maintained permissible, and upon start-up of the diesel generator, a functional test of each ground-fault and ground-wire monitor system shall be performed by a qualified electrician who meets the requirements of 30 CFR 75.153.
- 15. The diesel generator system shall not be operated until after MSHA has initially inspected the equipment and determined that it is in compliance with all the above terms and conditions.
- 16. The diesel generator system, when in use, shall comply with all other applicable requirements of the Federal Mine Safety and Health Act of 1977 and the applicable requirements of 30 CFR, Part 75.
- 17. Prior to using the diesel generator system, training shall be conducted for all qualified persons on the proper examination and test procedures to be utilized. The training shall be "hands on" specific, and shall be incorporated into the Part 48 training plan.
- 18. 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, at any of the listed mines, to the Coal Mine Safety and Health District Manager. These proposed revisions shall specify the following:
- a) The "hands on" specific training specified in Condition No. 16;
b) Initial and refresher training regarding the terms and conditions stated in the Proposed Decision and Order; and
c) Training in the hazards of setting short circuit interrupting device(s) too high to adequately protect the 480-volt, and 995-volt portable cables.
Any party to this action desiring a hearing on this matter must file in accordance with 30 CFR 44.14, as amended, (Federal Register 53430, December 28, 1990) 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 desire 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 |
