1/21/25
In the matter of Petition for Modification
Signal Peak Energy LLC
Bull Mountain Mine No.I
I.D. No. 24-01950 Docket No. M-2022-019-C
PROPOSED DECISION AND ORDER
On August 31, 2022, a petition was published in the Federal Register seeking a modification of the application of 30 CFR § 75.503 to Petitioner's Bull Mountain Energy Mine located in Roundup, Montana. The petitioner requested the modification to allow the use of trailing cables exceeding the length specified in 30 CFR § 18.35(a)(5)(i). 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.
30 CFR § 75.503 provides in part:
The operator of each coal mine shall maintain in permissible condition all electric face equipment required by §§75.500, 75.501, and 75.504 to be permissible which is taken into or used inby the last open crosscut of any such mine.
30 CFR § 18.35(a)(5)(i) provides in part:
(5) Ordinarily the length of a portable (trailing) cable shall not exceed 500 feet. Where the method of mining requires the length of a portable (trailing) cable to be more than 500 feet, such length of cable shall be permitted only under the following prescribed conditions:
(i) The lengths of portable (trailing) cables shall not exceed those specified in Table 9, Appendix 1, titled "Specifications for Portable Cables Longer than 500 Feet.
MSHA personnel conducted an investigation for the petition and filed a report of their findings with the Administrator for Mine Safety and Health Enforcement on November 21, 2022. After a careful review of the entire record, including the petition and MSHA's investigative report, this Proposed Decision and Order is issued.
Findings of Fact and Conclusions of Law
MSHA's investigation found that Signal Peak Energy LLC, Bull Mountain Mine No. 1, is located 18 miles south of Roundup, MT, on Fattig Creek Road. Bituminous coal is mined from the Mammoth seam with an average height of 108 inches and an entry width of 20 feet. Bull Mountain Mine No. 1 has six portals: entries 1 and 2 are returns, entry 3 is the belt, and 4 and 5 entries are exhausting. One slope entry, South Portal #3, is exhausting, which connects to 10 Right South Portal entries. A Spendrup 1750 HP fan supplies the air to the blowing ventilation system. One shaft is intake air located at XC-78 entry 6, and the other is exhausting at XC-98 entry 0. Explosive levels of methane or other gases have never been encountered at the mine.
Bull Mountain Mine No. 1 has three mechanized mining units (MMU). MMU 001-0 is currently developing the East Mains section with two Joy continuous miners, model No. 12CM12-11BX, two Fletcher bolters, model numbers CHDDR-13 and DDR-17, and two Joy shuttle cars, model number 10SC32. MMU 002-0 is idle. MMU 004-0 is a longwall section currently operating in 9 Right, which consists of 187 shields, Joy shear LWS619, Cathead and tailgate PF-6/1242, Cat crusher SK1220, Cat stage loader 616887, and a monorail system. Continuous mining sections affected by the PFM include longwall development, longwall recovery, longwall setup, mains development, and occasional rehab areas. The PFM involves 11-15 miners per shift, including equipment, utility, maintenance workers, and supervisors. Bull Mountain Mine No. 1 has four rotating crews working 12-hour shifts with 236 employees: 56 are salary employees, and 180 are hourly employees. The petitioner requests a modification of 30 CFR 75.503, specifically 30 CFR 18.35(a)(5)(i) to permit an increase of the trailing cables lengths up to 1000 feet maximum. The increase in trailing cable length will reduce the advancement of the unit power center. This reduces exposure of moving machinery, connecting, disconnecting, and hanging high voltage incoming power (21,600 VAC) and eliminates using a distribution box to extend these cables.
The #2 AWG trailing cable is more substantial than the smaller trailing cable. The petitioner alleges the alternate method of compliance will decrease the likelihood of cable damage and therefore enhance safety for miners handling the cable. The petitioner has not provided facts to support any of the statements submitted within this petition for modification including and related to reducing exposure of moving machinery, connecting, disconnecting and hanging high voltage power, elimination of distribution box, more substantial cable, decrease cable damage, or enhance safety. The petitioner does not provide facts that support improved safety and health for miners. MSHA requested the facts necessary to effectively evaluate the petition for modification. On November 21, 2024 the petitioner provided the minimum available fault current at the end of the proposed trailing cables.
The petitioner proposes to establish an alternative method in lieu of the mandatory safety standard:
The petitioner proposes No. 2 AWG, G-GC 3/C Mold-Cured jacket flat and round 2000 volt for 995-volt trailing cables used for shuttle cars and roofbolters be limited to 1,000 feet versus the
specified 700 feet. The petitioner proposes 2/0 shielded G-GC CPE Jacket 2000 volt for 995-volt trailing cables used for continuous mining machines be limited to 1,000 feet versus the specified 850 feet.
1) Mining Cycle and Pillar Sizes
The Bull Mountains Mine runs continuous miner sections with two shuttle cars, one (or two) roof bolters and two continuous miners. Cuts are made on 40' increments. Pillar dimensions are approved on centers up to 250'. Large block sizes are implemented for pillar stability, abutment control, and ventilation pressure loss. The use of distribution boxes is required in areas where large pillar sizes are implemented. This includes start lines, recovery rooms, and applications in mains development. Pillar centers (240' x 184') require distribution boxes to be installed and advanced every crosscut in order to maintain compliance with maximum trailing cable lengths.
The typical cut sequence and section layout for the development of the Mains. Pillar centers (222' x 90') require a distribution box to be installed and advanced every crosscut in order to maintain compliance with maximum trailing cable lengths. Distribution boxes are a redundant additional piece of electrical equipment that must be handled and advanced every crosscut, progressively, to achieve the same results of a 1000' trailing cable. (Note: The modification of the current standard will be applicable to all shuttle cars, roof bolting machines, and continuous mining machines)
2) Safety Precautions and Procedures as an Alternative to 30 CFR 75.503 (18.35(a)(5)):
a) The petition applies only to trailing cables supplying three-phase, 995-volt power to continuous mining machines, roof bolters, and shuttle cars.
b) The maximum length of 995-volt trailing cables will be 1,000 feet.
c) The size of 995-volt trailing cables will be:
i) No smaller than 2/0 for continuous mining machines.
ii) No smaller than No. 2 AWG for roof bolters and shuttle cars.
d) All circuit breakers used to protect 2 AWG trailing cables exceeding 700 feet in length or 2/0 cables exceeding 850 feet in
length shall have instantaneous trip units properly calibrated and adjusted to trip at no more than the smallest of the following values:
i) The setting specified in 30 CFR Part 75.601.
ii) The setting specified in the approval documentation for the machine, or
iii) 70% of the minimum phase to phase short circuit current available at the end of the trailing cable.
e) Cable size and maximum allowable circuit breaker instantaneous settings will be labeled at the breaker. In addition, permanent warning labels will be installed and maintained warning miners not to change or alter the short-circuit settings.
f) Prior to each production shift, persons designated by the operator will visually examine trailing cables to ensure that the cables are in safe operating condition and that the instantaneous settings of calibrated breakers are in compliance with labeled settings.
g) Any trailing cable that is not in safe operating condition shall be removed from service immediately and repaired or replaced.
h) Each splice or repair to the trailing cables shall be made in a workmanlike manner and in accordance with the instructions of the manufacturer of the splice repair kit. Splices will be made with an MSHA approved splice wrap.
i) The petitioner's alternative method will not be implemented until all miners who have been designated to examine trailing cables and verify instantaneous settings have received all the elements of training specified in this petition.
3) Mine Power Configuration and Short Circuit Calculations
a) The mine operator is to provide the calculations for the amperages in the one-line diagram.
b) The short circuit analyses based on the current configuration of the mine power system along with the type and length of cable. In the Short Circuit 3-Phase Ground Report the Symmetrical KA instantaneous setting are set to trip at the lowest possible short circuit current.
c) Short Circuit Report for the individual equipment and associated breaker Time Current Curve (i.e. B3 Short-Circuit Report and B4 associated breaker Time Current Curve) verifies that the breaker will trip on instantaneous trip below the MSHA minimum available short circuit current.
d) The settings are indicated with the respective protection values with those settings on the Breaker Time Current Curves, for each individual piece of equipment. The circuit with the CM will have a setting of "F" as the circuits with RBs and SCs will have a setting of "E".
e) The normal inrush for the equipment on the 1,000-foot cable circuits are as follows below:
i) CM (Continuous Miner) - The total inrush current would be 897A, below the instantaneous trip level of 1,S00A.
ii) RB (Roof Bolter)-The total inrush current will be 384Awhich is below the instantaneous trip level of 7S0A.
iii) SC (Shuttle Car) - The total inrush current will be 330A which is below the instantaneous trip level of 7S0A.
f) The section transformer T-PCl 7 no-load voltage is 99SV.
g) The full load to stall maximum current is listed for each circuit and piece of equipment as indicated on Electrical One-line:
i) PCl 7-CKTl - RBS - 63.2A
ii) PCl 7-CKT2 -CMS - 247A
iii) PCl 7-CKT8 - RB2 - 63.2A
iv) PCl 7-CKT9 - SCS - 147A
v) PCl 7-CKTl0 - SC6 - 147A
h) The breaker settings are indicated on the breaker time current curves for each of the individual 1,000-foot cable circuits.
i) The no-load voltage value at the PCl 7, Section Transformer, will be 995V.
j) The type, make, and model for the equipment affected in this petition. The Short Circuit Calculation program used to evaluate the mine system was ETAP. The information was from Eaton manufacture data for E2KM and E2NM style breakers for No. 2 AWG-GC 2000-volt and 2/0 AWG-GC shielded 2000-volt cables used for the 995-volt systems for the shuttle cars, roofbolters, and continuous miners.
The petitioner asserts that the alternate method proposed will at all times guarantee no less than the same measure of protection afforded the miners under the mandatory standards.
The petitioner submitted a short circuit analysis based on the configuration of the mine power system using the proposed trailing cable sizes and lengths to be used with the continuous mining machine, model No. 12CM12-11BX, roof bolting machines, model numbers CHDDR-13 and DDR-17, and two shuttle cars, model number 10SC32. The short circuit study indicates that the proposed circuit breakers can adequately protect the subject trailing cables when they are properly set.
Eaton is a manufacturer of molded case circuit breakers, and they test breakers in compliance with Underwriter's Lab (UL) Standard 489. UL 489 is the standard for molded case circuit breakers. UL 489 has tests which it refers to as "standard" interrupting tests for molded case circuit breakers. A more appropriate term would be "base" or "lowest" interrupting level that any circuit breaker of a given rated voltage and amp rating must meet. UL489 MCBs feature two different tripping mechanisms, the delayed thermal tripping mechanism for overload protection, and the magnetic tripping mechanism for short circuit protection. For breakers with adjustable short circuit protection, only the lowest and highest trip points settings are tested to trip within 80% to 130% of the rated trip value. (Example: to pass, a breaker at a 1000-amp (minimum or maximum only) setting must trip between 800 to 1,300 amps. A breaker passing the tests at the lowest and highest settings is considered calibrated. However, circuit breakers protecting trailing cables covered under petitions for modification for extended length must be 'specially calibrated' at the specified petition setting for the covered cable. This special calibration setting must be secured (locked, adjustment disabled, tamper proof, sealed) and permanently labeled (certified and identified) by the circuit breaker manufacturer or competent repair facility outfitted with calibrated test equipment. This labeling must be maintained legible on the breaker and readily visible for inspection. Documentation must be provided by the circuit breaker manufacturer or competent repair facility outfitted with calibrated test equipment; of the tolerance the breaker was calibrated to (Example 30%). The operator must ensure that the available fault current provided at the breaker is at or above the setting plus the calibration tolerance. (Example: a breaker calibrated at 800 amps with 30% tolerance must have available fault current of 800 x 130% = 1,040 amps. A short circuit analysis which accurately determines the minimum phase to phase short circuit current available at the end of the affected trailing cables shall be made available to MSHA personnel upon request. The short circuit analysis shall be updated whenever changes are made to the mine power system that affect the fault current available at the end of the affected trailing cables and the specified settings used to protect these trailing cables.
In order to verify the proper settings these circuits must be calibrated. All circuit breakers used to power the trailing cables used for the purposes of this petition shall be calibrated: A calibration is the process by which each device is tested with precision instrumentation to determine the deviation from standard and ascertain the proper correction, capacity or the graduation thereof. This verifies the condition, performance, sensitivity and the accuracy of the setting of the electrical device. A record of calibration or certificate shall be maintained by the petitioner and made available upon request of an Authorized Representative (AR)ofthe Secretary of Labor. A certificate is a written declaration issued for each tested and calibrated device. These calibrations, periodic testing of performance is an essential maintenance process to mitigate potential hazardous operational concerns. These precise testing methods are frequently performed by testing laboratories. The ability of a circuit breaker to reliably disconnect in the case of overcurrent or during faulted conditions is a matter of required protection for miners. This protection is dependent on the correct application of the settings for each circuit. Such calibration shall be performed initially and periodically thereafter to ensure that the settings for each circuit are properly maintained. ANSI/NETA MTS (Standard for Maintenance Testing Specifications), Appendix B, recommends that low voltage molded case circuit breakers be electrically tested every 36 months for circuit breakers in average condition with average reliability requirements. The frequency of testing may vary depending on the condition of the breaker and the required reliability. Part of this test is primary current injection to verify the tripping current. The circuit breaker manufacture should be consulted for each specific circuit breaker and trip unit to determine re-calibration schedules.
NFPA 70B (Standard for Electrical Equipment Maintenance), Table 15.4.5, recommends that low voltage molded case circuit breakers be electrically tested every 60 months for circuit breakers in "like new" condition. The frequency may be as often as every 12 months depending on the condition of the breaker. Part of this test is primary current injection to verify the tripping current.
It is critical to ensure that the circuit breaker will trip at the required value therefore this equipment must be recalibrated at least every 36 months unless additional information provided by the manufacturer determines otherwise.
According to 30 CFR § 75.900-3 Testing, examination, and maintenance of circuit breakers; procedures - Circuit breakers protecting low- and medium-voltage alternating current circuits serving three-phase alternating current equipment and their auxiliary devices shall be tested and examined at least once each month by a person qualified as provided in Sec. 75.153. In performing such tests, actuating any of the circuit breaker auxiliaries or control circuits in any manner which causes the circuit breaker to open, shall be considered a proper test. All components of the circuit breaker and its auxiliary devices shall be visually examined and such repairs or adjustments as are indicated by such tests and examinations shall be carried out immediately.
According to 30 CFR § 75.900-4 Testing, examination, and maintenance of circuit breakers; record - The operator of any coal mine shall maintain a written record of each test, examination, repair, or adjustment of all circuit breakers protecting low- and medium-voltage circuits serving
three-phase alternating current equipment used in the mine. Such record shall be kept in a book approved by the Secretary. These test and records shall be conducted and provided by qualified personnel.
The petitioner notified miners regarding the terms of this petition by posting the petition on the mine bulletin board. MSHA also interviewed miners as part of its investigation, and they did not raise safety concerns and were in favor of the petition.
MSHA finds that the alternate method proposed by the Petitioner (and as amended herein by MSHA) will at all times guarantee no less than the same measure of protection afforded the miners under§ 75.503.
ORDER
Wherefore, pursuant to the authority delegated by the Secretary of Labor to the Administrator for Mine Safety and Health Enforcement, and pursuant to Section l0l(c) of the Federal Mine Safety and Health Act of 1977, 30 U.S.C., Sec. 81l(c), it is ordered that Signal Peak Energy LLC. Petition for Modification at Bull Mountain Mine No 1 for the application of 30 CFR § 75.503 is hereby:
GRANTED, for trailing cables supplying three-phase power to 995 VAC continuous mining machines and trailing cables supplying three-phase Fletcher CHDDR-17 double-boom bolting machines, and shuttle cars. The petition is granted for the maximum lengths of 1000 feet of trailing cable only when necessary to mine longwall panels when larger coal pillars with crosscut centers greater than 200 feet and not exceeding a maximum of 250 feet are used in Bull Mountain Mine No 1, conditioned upon compliance with the following terms and conditions:
1. The maximum length of 995 VAC trailing cables shall be 1000 feet.
2. The 995 VAC continuous mining machines' trailing cables shall not be smaller than 2/0 American Wire Guage (AWG). The trailing cables supplying power to 995 VAC roof bolting machines, shuttle cars shall not be smaller than #2 AWG.
3. All components that provide short-circuit protection shall have a sufficient interruption rating in accordance with the maximum calculated fault currents available. All electrical protection devices used to protect trailing cables exceeding the maximum length specified in 30 CFR § 18.35(a)(5)(i) shall have instantaneous devices properly calibrated and adjusted to trip at no more than smallest of the following values:
a. the setting specified in 30 CFR § 75.601-1.
b. the setting specified in the approval documentation for the machine; or
c. 70% of the minimum phase to phase short circuit current available at the end of the trailing cable.
The short circuit analysis shall be updated whenever changes are made to the mine power system that affect the fault current available at the end of the affected trailing cables and the specified settings used to protect these trailing cables. An updated short circuit analysis which accurately determines the minimum phase to phase short circuit current available at the end of the affected trailing cables shall be kept and made available to an authorized representative of the Secretary and to the miners in such mine.
4. All electrical protection devices used to protect trailing cables covered by this petition shall be calibrated, legibly labeled, protected, secured, and maintained according to the manufacturers recommendation and as specified in this Proposed Decision and Order.
The electrical protection devices shall be calibrated as defined including by a certified representative of the manufacture of the devices at least every 36 months or a frequency based upon information provided by the manufacturer. A record of the most up to date calibration for the testing equipment shall be made available for review.
The calibrated trip setting of these circuit breakers shall be secured so that the setting cannot be changed. The devices shall be protected by a clear see through lockable or secured cover plate.
5. At the beginning of each production shift, persons designated by the mine operator shall visually examine the trailing cables to ensure that they are in safe operating condition. The instantaneous settings of the calibrated electrical protection devices shall also be visually examined to ensure that the settings are secured and do not exceed the settings specified in this Proposed Decision and Order.
6. Any trailing cable that is not in safe operating condition shall be removed from service immediately and repaired or replaced.
7. Each splice or repair in the trailing cables 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 material that has been accepted by MSHA as flame resistant. Splices shall comply with the requirements of 30 CFR §§ 75.603 and 75.604.
8. Permanent warning labels shall be installed and maintained legible on the cover(s) of the power center or distribution box identifying the location of each secured short circuit protective device. These labels shall warn miners not to change or alter these settings. Any evidence of tampering with the settings or any unauthorized use shall prompt notification to the District Manager for Mine Safety and Health Enforcement for the area in which the mine is located. All cable couplers for these cables shall be constructed or designed, for example keyed or sized, to permit only the proper type and length of cable to be plugged into the receptacle with the proper settings.
9. In the event the mining methods or operating procedures cause or contribute to the damage of any trailing cable, the cable shall be removed from service immediately and repaired or replaced. Also, additional precautions shall be taken to ensure that haulage roads and trailing cable storage areas are situated to minimize contact of the trailing cable with all mobile equipment used at the mine. Moreover, trailing cable anchors on cable reel equipment shall be of the permanent type as recommended by the manufacturer and that minimizes the tensile forces on the trailing cables.
10. Where the method of mining requires that trailing cables cross roadways or haulage ways, the cables shall be securely supported from the mine roof, or a substantial bridge for equipment to pass over the cables shall be provided and used.
11. Excessive cable shall be stored behind the anchor, on equipment that use cable reels, to prevent cables from overheating.
12. The Petitioner's alternate method shall not be implemented until miners who have been designated to examine the integrity and security of the system, to verify the short-circuit settings, and to examine trailing cables for defects and damage and have received the training specified in Item 15. Only qualified electricians shall frequently examine, test, and properly maintain this equipment which includes work after the circuit would trip due to a fault initiated by the circuit breaker.
13. 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 District Manager for Mine Safety and Health Enforcement for the area in which the mine is located. The proposed revisions shall specify task training, for persons who perform the examinations listed in Item 7, that includes the following elements:
(a) Training in the mining methods and operating procedures that will protect the trailing cables against damage;
(b) Training in proper procedures for examining the short circuit interrupting device(s) and trailing cables to ensure that they are in safe condition;
(c) Training in the hazards of setting the short circuit interrupting device(s) too high to adequately protect the trailing cables;
(d) Training in how to verify that the short circuit interrupting device(s) protecting the trailing cable(s) are properly set and maintained; and
(e) Training on how to protect trailing cables against damage caused by overheating when excessive cable is stored on the cable reel, and the importance of adjusting stored cable behind the cable anchor as tramming distances change. The procedures, as specified in 30 CFR § 48.3, for approval of proposed revisions to already approved training plans shall apply.
14. Unless specifically mentioned herein, nothing in this Proposed Decision and Order changes or supersedes the requirements otherwise imposed by the Mine Act, other mandatory standards or regulations, or approved ventilation or other plans.
Any party to this action 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 Mine Safety and Health Enforcement, 201 12th Street South- Suite 401, Arlington, Virginia 22202- 5452.
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 may 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.
Brian Goepfert,
Administrator for
Mine Safety and Health Enforcement
Certificate of Service
I hereby certify that a copy of this proposed decision was served personally or mailed, postage paid, or provided by other electronic means this 21 day of January 2025 . to:
Curtis Focht, P.E.
cfocht@signalpeakenergy.com
John Mcfarlen
jmcfarlen@signalpeakenergy.com
Spencer Callahan scallahan@signalpeakenergy.com Parker Phipps, CEO correspondence@signalpeakenergy.com
Avichai Ozur Bass
Mine Safety and Health Specialist
cc: Mr. Dan Walsh, Bureau Chief Montana Department of Environmental Quality (DEQ), Mining Bureau, P.O. Box 200901, Helena, Montana 59620 dwalsh@mt.gov