Petition for Modification
In the matter of
Canyon Fuel Company, L.L.C.
Dugout Canyon Mine
I.D. No. 42-01890
Docket No. M-2000-172-C
30 CFR 75.352
PROPOSED DECISION AND ORDER
On December 27, 2000, a petition was filed seeking a modification of the application of 30 CFR 75.352 to Petitioner's Dugout Canyon Mine, located in Carbon County, Utah. Also on December 27, 2000, a complementary petition was filed seeking modification of 30 CFR 75.350. The Petitioner proposes to conduct longwall mining using the two-entry system. Petitions of both standards are necessary to employ the two-entry mining system. The Petitioner alleges that application of this standard will result in a diminution of safety to the miners and 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.
The petitioner alleges that the use of two-entry longwall development mining systems reduces the likelihood of coal bumps, roof falls, rib rolls, and other hazards related to mining under deep cover, multiple seam extraction, or highly faulted and stressed ground conditions. Therefore, developing with additional entries to comply with isolation of the belt entry from a separate return entry and diverting belt air directly into the return aircourse diminishes the safety of miners as compared to utilizing the belt entry as a return aircourse during development mining, provided appropriate atmospheric monitoring and early warning fire detection and other precautions are utilized. Also, the petitioner alleges that the proposed alternate method outlined in the petition to use the belt entry as an intake air course to ventilate the longwall face during retreat mining will at all times guarantee no less than the same measure of protection afforded by the standard. The same diminution of safety and alternative method allegations apply to the application 30 CFR 75.350 (which prohibits belt haulage entries to be used to ventilate active working places), but are addressed by petition under a separate docket No. (M-2000-171-C).
MSHA personnel conducted an investigation applicable to both petitions 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 recommendation, this Proposed Decision and Order (PDO) is issued.
Finding of Fact and Conclusion of Law
As part of the investigation, District 9 and the Ground Support Division of MSHA's Pittsburgh Safety and Health Technology Center (PSHTC) conducted evaluations of the ground control aspects of the Petitioner's Dugout Canyon Mine, and submitted reports of their findings. The reports concluded that the geologic conditions present at the mine, including sand channels, faults, depths of cover, massive stiff rock layers above and below the seams, and multiple seam extraction, are conducive to the occurrence of bounces and bumps. Mine history, published documentation, as well as analysis, indicates that bumps and bounces occur at cover depths as little as 500 feet.
Heavy bumps and bounces were regularly experienced in the Petitioner's nearby Soldier Canyon mine during retreat mining. At least one of the events, in 1993, was assigned a local magnitude of 3.6 by the National Earthquake Information Center. A study conducted in 1990 at the Soldier Canyon mine determined that 19 of 23 injuries for the period studied were associated with pillar bumps at cover depths of 1,500 to 2,000 feet. Due to the conditions at the Soldier Canyon mine, a petition for modification, Docket No. M-89-182-C, was granted to permit two-entry longwall mining. Longwalls were not, however, deployed at Soldier Canyon before the mine permanently closed.
Similarly, a documented history of hazards associated with retreat mining in this formation exists for the Sunnyside complex of mines located 14 miles to the southwest of Dugout Canyon mine. Information developed by the Bureau of Mines shows that retreat mining in overburden depths as little as 500 feet was prone to severe pillar bumps and bump-related roof falls. A 1994 Circular published by the Bureau of Mines concluded that a two-entry yield pillar system had virtually eliminated severe tailgate pillar bumps and contributed to reducing bumps near the tailgate corner at Sunnyside. Two-entry longwall mining was successfully conducted at the nearby Sunnyside complex for many years.
As indicated by PSHTC in its report, current ground conditions at Dugout Canyon Mine (i.e., depths over 1000 feet, multiple seam mining, sand channels and faults) are conducive to the occurrence of bumps. Prior experience in Utah has led to establishing two-entry gate roads with a yield pillar to minimize the potential for face and pillar outbursts and bumps. Two-entry yield pillars, as compared with multiple entry yield pillar configurations, transfer less load onto the active panel and tailgate chain pillars during extraction of the active longwall panel. Two-entry mining offers the added benefit of minimizing exposure to difficult ground conditions by providing a minimized span and stability advantage compared to multiple entry yield pillar designs. The two-entry system also offers a minimized exposure to fractured roof and strata discontinuities encountered during development. Since the Dugout reserves possess a high incidence of faulted and fractured ground, decreasing the number of entries driven in gate development will reduce the exposure to weakened ground. Therefore, from a safety perspective, it is advantageous to develop two-entry gate roads for future longwall mining at the Dugout Canyon Mine.
Due to the documented hazards associated with mining in this coal seam(s), application of 30 CFR 75.352 to the subject mine will result in a diminution of safety to the miners and the special terms and conditions set out below will at all times provide a safe work environment to the miners.
On the basis of the petition and the findings of MSHA's investigation, Canyon Fuel Company, L.L.C., is granted a modification of the application of 30 CFR 75.352 to its Dugout Canyon 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 Canyon Fuel Company, L.L.C.'s Petition for Modification of the application of 30 CFR 75.352 in the Dugout Canyon Mine is hereby:
GRANTED, for use of belt air in a return aircourse during development of a two-entry longwall mining system, conditioned upon compliance with the following:
The terms and conditions specified in the Proposed Decision and Order granting the modification of 30 CFR 75.350, Docket No. M-2000-171-C, must be followed.
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 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