Mine Safety and Health Administration (MSHA) - Report of ...

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At 4:41 a.m., Grosely called the mine and issued an order pursuant to section 103(k) of the Mine Act that prohibited all activity in the section until MSHA determined that it was safe to resume normal mining operations in the affected area. The order also required the mine operator to obtain prior approval from an authorized representative for all plans to recover or restore operations to the affected area. Five minutes later, a magnitude 2.1 seismic event occurred near the South Barrier section, followed by two smaller events within the next two minutes. Underground Rescue Efforts Underground rescue efforts were initiated on the morning of August 6. These efforts included exploring approaches to the South Barrier section, restoring ventilation, cleaning up the rubble in approaches to the South Barrier section, and breaching the No. 1 seal in Main West. Grosely, the first MSHA employee on site, arrived at 5:44 am. Thereafter, MSHA evaluated the mine operator’s specific rescue plans and approved them under the 103(k) order. GRI’s command center was established on the second floor of the warehouse building as required in their Emergency Response Plan. The MSHA Mine Emergency Operations (MEO) mobile command center vehicle arrived from Price, Utah, at 10:15 a.m. It was parked near the entrance to the mine portal access road, adjacent to GRI’s command center. MSHA and GRI jointly coordinated the rescue efforts from these locations. Efforts also were made to locate the entrapped miners with seismic equipment and by drilling boreholes. Allyn Davis (MSHA District 9 manager) arrived on the afternoon of August 6 and assumed control of MSHA’s onsite responsibilities. Richard Stickler (Assistant Secretary of Labor) and Kevin Stricklin (Administrator for Coal Mine Safety and Health) arrived during the afternoon of August 7. Three MSHA Technical Support roof control specialists worked onsite during the rescue and advised MSHA decision-makers on roof control issues. They consulted with other Technical Support employees and outside experts. Details of the rescue efforts are explained in the following sections of this report. Attempts to Explore South Barrier Section and Main West Sealed Area The operator developed a plan to remove debris from the South Barrier No. 4 entry and to use mine rescue teams to search for an access route to the entrapped miners. Under this plan, mine rescue teams would explore all approaches to the South Barrier section. If no route to the section could be found, the operator intended to breach the Main West No. 1 seal. Mine rescue teams would explore for a route through the Main West entries to a point adjacent to the entrapped miners, where they could drill or mine through the remaining barrier pillar into the working section. The operator presented this plan to MSHA and, at 6:00 a.m. on August 6, Grosely modified the 103(k) order to “permit the necessary personnel to travel underground to make repairs to damaged ventilation devices, work on installing a belt tailpiece and feeder breaker at crosscut 120 in the number two entry, clean and advance in the No. 4 entry towards crosscut 124 and to open the number one seal in the Old Main West entries inby crosscut 118 and use mine rescue teams to explore within established mine rescue procedures. Ventilation will be established as necessary for the operation of necessary mining equipment. Additional equipment and materials will be moved underground as deemed necessary for current recovery operations.” At 6:40 a.m., fourteen members of the UEI mine rescue teams entered the mine to explore approaches to the section (see Figure 3). Eighteen other miners remained in the mine to repair ventilation controls, set up the feeder/breaker, belt tailpiece, and begin the clean-up work. All other miners were evacuated from the mine. At 7:40 a.m., Taylor debriefed Harper, Ward, and 14
Pritt. Ward told Taylor that the crew was mining off the No. 1 entry at crosscut 139 into the barrier before he left the section. After 8:00 a.m., mine rescue team members from Energy West Mining Company also entered the mine. Grosely, Randy Gunderson (MSHA coal mine inspector), and a group of miners, including mine rescue team members, explored approaches to the South Barrier section by traveling back and forth between the Nos. 1 and 4 entries in an attempt to find a route to the entrapped miners. Entries and crosscuts were largely filled with debris, while intersections were less filled. They advanced to crosscut 126 where they encountered debris within inches of the roof and oxygen below 16%. A decision was made to retreat. Figure 3 - South Barrier Section Rescue Area Showing Ground Conditions and Rescue Attempts. Rescuers attempted to provide breathable air to the entrapped miners by utilizing the fresh water pipeline along the conveyor belt. The water was shut off and the pipeline was drained as much as possible by opening fire valves. A PED message stating “OPEN VALVE ON H2O 4 AIR” was sent to the cap lamp Erickson was wearing. Erickson was the only entrapped crew member wearing a PED device. A compressor was set up between crosscuts 109 and 110 in the No. 2 entry. The compressor was attached to the water line and started. A second PED message stating “PUMPING AIR THRU WATERLINE” was sent at 11:04 a.m. By noon, the mine rescue teams had established a fresh air base (FAB) one crosscut outby the No. 1 seal and began the arduous work of breaching the seal. At 1:55 p.m., the teams reported to the command center that a 3 x 3-foot area of material, 8 inches deep into the seal, had been removed. By 2:50 p.m., a small opening through the seal had been made and by 3:20 p.m., a 2 x 2-foot hole was completed through the seal. Brad Allen (MSHA coal mine inspector/Mine Emergency Unit (MEU) member) and five mine rescue team members entered the sealed area and began exploration at 4:42 p.m. The 15
Page 1: CAI-2007-15-17, 19-24 UNITED STATES
Page 4 and 5: TABLE OF CONTENTS EXECUTIVE SUMMARY
Page 6 and 7: Appendix C - Safety Zone Map ......
Page 8 and 9: Figure 42 - Illustration of ARMPS I
Page 10 and 11: Figure 1 - Map of Accident Sites
Page 12 and 13: pillars near the pillar line and th
Page 14 and 15: submit written reports of these acc
Page 16 and 17: Power’s 50% ownership of the Cran
Page 18 and 19: Table 1 shows recent Non-Fatal Days
Page 20 and 21: stoppings from the accident site ou
Page 22 and 23: Peacock told Hardee that an overcas
Page 26 and 27: irrespirable atmosphere behind the
Page 28 and 29: Rescue Efforts in South Barrier Sec
Page 30 and 31: etween crosscut 119 and 120 until R
Page 32 and 33: Figure 7- Damaged Roof Bolts and To
Page 34 and 35: Figure 10 - No. 1 Entry Packed with
Page 36 and 37: machine cutter motors required repa
Page 38 and 39: Figure 13 - 20-foot Deep Void over
Page 40 and 41: The night shift crew members were t
Page 42 and 43: Figure 15 - Clean-up Area Following
Page 44 and 45: Borehole No. 1 was drilled using a
Page 46 and 47: Figure 20 - Surface Location of Bor
Page 48 and 49: Table 3 - Analysis Results of Air S
Page 50 and 51: This was the projected mine locatio
Page 52 and 53: epresentatives of the mine operator
Page 54 and 55: DISCUSSION The Crandall Canyon Mine
Page 56 and 57: displacements is very consistent wi
Page 58 and 59: Figure 23 - General Stratigraphic C
Page 60 and 61: grids. In mid-2005, the mine adopte
Page 62 and 63: corresponding pillar damage at seam
Page 64 and 65: Borehole Observations Conditions de
Page 66 and 67: Figure 31 - Surface Deformation fro
Page 68 and 69: Twelve seismic events were recorded
Page 70 and 71: Summary - Nature and Extent of Fail
Page 72 and 73: the seam and leaving roof coal in t
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In the Main West entries, some infl
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North Barrier Section Development I
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Larger stumps were left unmined in
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South Barrier on the BLM coal lease
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the Main West No. 1 entry at crossc
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us.” Although Peacock characteriz
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empirically derived and should not
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ARMPS StF’s, depth of cover, and
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Figure 44 - 1st North Mains Left Pa
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Figure 46 - South Mains ARMPS Calcu
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Figure 47 - Methods of Incorporatin
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Summary. ARMPS stability factors fo
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Figure 49 - Element Safety Factors
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Figure 51 - Element Safety Factor D
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Like all numerical methods, BEM res
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Figure 53 - LaModel Grid Boundaries
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Similarly, a sudden change in stres
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The magnitude and distribution of i
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was completed, this effect was nega
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B 8 ft mined height 80 ft Wide Remn
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2.0 without bottom mining with bott
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A 2.0 B C 1.8 1.6 1.4 1.2 1.0 0.8 0
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Critique of Mine Design The enginee
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methods. The design widths shown he
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Also, the 130-foot dimension is app
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program, LamPre, offers a utility t
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very little feedback from the field
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AAI’s LaModel model was calibrate
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After the initial calibration proce
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oad area (Figure 75). In this figur
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South Barrier Design. After the Mar
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Minimum PStF in the North Barrier s
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AAI recognized that the North Barri
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Roof Control Plan Section 30 CFR 75
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control plan. The entries and cross
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A 55-foot barrier between the South
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section, miners recognized that gro
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The main fan installation consisted
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Originally, the South Barrier secti
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Three sources of the oxygen deficie
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Table 13 - Handheld Gas Detector Co
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drill rod and bit were left in the
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It was feasible to acquire a specia
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The call lasted five minutes. Allre
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each hole. The microphone was not r
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parameters, and mine emergency scen
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Advance rate in the No. 1 entry bet
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GRI furnished a map to MSHA during
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During most of the rescue work in t
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Seismic Activity Recorded by UUSS d
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Pillar Bounce and Burst Activity du
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indicative of an impending burst we
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day. When the accident occurred, th
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4. Root Cause: GRI included incorre
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The mine designs recommended by AAI
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ENFORCEMENT ACTIONS An order was is
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Type of Issuance: 104 (d) (2) Order
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Mine Safety and Health Administrati
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B-2
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B-4
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Appendix C - Safety Zone Map
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Appendix E - AAI May 5, 2000, Repor
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E-3
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E-5
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Appendix F - AAI July 20, 2006, Dra
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F-3
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F-5
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F-7
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F-9
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F-11
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F-13
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F-15
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F-17
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F-19
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F-21
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F-23
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F-25
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F-27
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F-29
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F-31
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G-2
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G-4
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G-6
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G-8
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G-10
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G-12
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G-14
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G-16
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G-18
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G-20
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G-22
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G-24
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G-26
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G-28
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G-30
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G-32
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H-2
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H-4
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H-6
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I-2
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I-4
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I-6
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I-8
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I-10
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J-2
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J-4
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Appendix K - Massive Pillar Collaps
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Appendix L - Subsidence Data Inform
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Figure 98 - USGS InSAR Image of Sub
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The contours on the USGS results we
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InSAR provides a more reliable char
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Appendix M - Neva Ridge Technologie
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1 Introduction 1.1 Data Description
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Each color cycle means 10 cm of dis
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Vertical Contours ∆=5 cm 5 10 25
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Appendix N - Seismic Analysis Unive
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provide similar results on average
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Figure 107 - Observed and Calculate
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Figure 108 shows all of the calcula
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Figure 111 shows the seismograph st
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Figure 113 - Depth Analysis of Augu
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Appendix O - Images of March 10, 20
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O-3
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O-5
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O-7
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O-9
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O-11
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Appendix P- ARMPS Method Using Barr
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FINITE ELEMENT ANALYSIS OF BARRIER
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INTRODUCTION This report discusses
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Generally, excavation takes place i
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Mine Geometry The overall region us
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Premining Stress The premining stre
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(2) An alternative form of (1) that
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There is a possibility that compute
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Figure 5. Element safety factor dis
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through a pillar. This variation is
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Figure 8a shows displacements in th
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Element Safety Factor Distributions
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Figure 10. A half-mesh view of elem
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Figure 12. Distribution of element
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Figure 14. Element safety distribut
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Figure 17 shows the distribution of
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Figure 18. Post-excavation pillar s
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would be of even more concern at gr
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A potentially important inelastic e
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A multi-stage mining sequence was f
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Pariseau, W. G. (1981) Inexpensive
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Appendix S - Back-Analysis of the C
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Executive Summary On August 6 th ,
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Page 3.5.2.2 Joint Slip ...........
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1. Objective The objective of this
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• The Rock Mass Stiffness • The
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types of field measurements are qui
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ARMPS Stability Factor 2 1.5 1 0.5
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or past, failure. Back-analysis is
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umps. Since LaModel does not have a
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appropriate values in the post-fail
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3. The LaModel Analysis 3.1 Approac
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Figure 3.2 Rib and pillar failure i
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Five and 6 ft wide elements were al
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3.4.2 Determining the Gob Stiffness
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strength formula, this implies that
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The model results illustrated in Fi
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1600 1600 2000 1600 1600 A. Pillar
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1600 1600 2000 1600 A. 3.8% Stronge
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changes are necessary to replicate
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1600 1600 2000 1600 A. Step 5 - Sou
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1600 1600 2000 1600 A. Step 6 - 2 P
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further improved. Obviously, there
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in to crosscut 146 in the bleeder a
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1600 1600 2000 1600 1600 A. Step 9
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36% of insitu load. With these two
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References Barron, K., 1992, “A R
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Appendix T - Abutment Load Transfer
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AAI used departs somewhat from that
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I H H H H H H G F F F F H H H H H H
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Appendix W - MSHA Main West 2006 AR
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Figure 118 - South Barrier MSHA 200
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The ventilation plan amendment to r
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X-4
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X-6
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X-8
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Azimuth - A surveying term that ref
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Coda Magnitude - The coda magnitude
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Formation - Any assemblage of rocks
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Methane - A potentially explosive g
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Identified coal resources are class
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Slabbing - A method of mining pilla
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Appendix Z - References 1 USBM dict
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