DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
Rocky Mountain District
Metal and Nonmetal Mine Safety and Health
ACCIDENT INVESTIGATION REPORT
UNDERGROUND NONMETAL MINE
FATAL COLLAPSE OF MINE WORKINGS ACCIDENT
Solvay Minerals Inc. Mine [I.D. No. 48-01295]
Solvay Minerals Inc.
Green River, Sweetwater County, Wyoming
February 3, 1995
Supervisory Mine Safety and Health Inspector
Mine Safety and Health Inspector
P.O. Box 25367 DFC
Denver, CO 80225-0367
Robert M. Friend, District Manager
At about 8:30 a.m., on February 3, 1995, a massive pillar failure occurred underground which collapsed the entire southwest section of the mine. At the time of the accident, 54 persons were in the mine, which included two employees of an independent contractor.
Two miners, Michael A. Anderson and Daniel A. Jereb, were unaccounted for following evacuation of the mine. Rescue teams from the surrounding area worked around the clock attempting to locate the two missing miners. Jereb was successfully rescued the following day. Anderson was rescued on February 5, but died while being taken out of the mine.
The Solvay mine, an underground trona operation, owned and operated by Solvay Minerals Inc., is located approximately 20 miles west of Green River, Sweetwater County, Wyoming.
Principal on-site operating officials were:
Richard Casey, Resident Manager
Ronald Hughes, Mine Operations Manager
Larry Refsdal, Senior Mine Engineer
The mine was normally operated two, 12-hour shifts a day, seven days a week. Employment at the mine totaled 414 persons; of this number, 163 worked underground.
Mining was done on one level by the room-and-pillar method utilizing boring machines and continuous miners. Ore was removed from the working panels via a belt conveyor system and then transported to the production shaft where it was stored prior to hoisting to the surface for further processing.
Access to the mine was through two circular, concrete-lined vertical shafts separated by about 500 feet. Primary access was through the production shaft which was located just north of the surface office facilities. It was 26 feet in diameter and extended 1,637 feet from the surface. The production shaft was divided into two compartments by a steel and plastic curtain wall which provided intake airflow into the mine. One compartment was used for hoisting ore and the other was for personnel and materials.
The second shaft was 18 feet in diameter and extended to a depth of 1,550 feet. Ventilation was provided by an exhausting axial-vane fan located on the surface. An emergency escape capsule/hoist arrangement was provided in this shaft. The capacity of the capsule was four persons.
The last regular inspection of this operation was completed on December 20, 1994. All miners had received training in accordance with 30 CFR Part 48. Two fully equipped rescue teams were maintained in ready status at the mine.
The Solvay mine was classified as a Category III gassy mine, in
accordance with 30 CFR 57.22003 and liberated about 900,000 cubic
feet of methane a day.
Trona, an evaporite mineral, is chemically composed of sodium sesquicarbonate (Na2CO3, NaHCO3, 2H2O) which is a mixture of sodium carbonate, sodium bicarbonate and water. Trona is the richest known natural source of soda ash (sodium carbonate Na2 CO3) which is an industrial chemical used primarily to manufacture glass. Trona production from the Green River, Wyoming Basin accounts for more than 25% of the world's supply.
The trona deposits near Green River were formed in a huge lake called Lake Gosiute during Eocene time, about 50 million years ago. About 7,000 feet of sediments accumulated in this lake during that time. These sediments were divided into three formations: the Wasatch, the Green River and the Bridger. The Green River formation is in turn subdivided into three members: the Tipton, Wilkins Peak and Laney. The Wilkins Peak member is composed of interbedded oil shales and marlstones that host the trona deposits.
Twenty-five distinct trona beds have been identified and are numbered up the stratigraphic column from oldest to youngest. The trona deposition resulted from major climatic changes toward a more arid environment. During wet periods, shale and carbonate deposition occurred. However, during dry periods when the closed lake diminished in size, trona and halite deposition occurred.
Trona mining at the Solvay Mine is in bed 17 which lies at depths
of 1,500 to 1,700 feet. The immediate roof at this mine consists
of claystones, mudstones, and oil shales. Typically the roof
rocks are competent and ground support problems are minimal. The
immediate floor consists of about 6 feet of oil shale overlaying
weak claystones and mudstones. Over time, floor heaves have
occurred in the mined-out areas; however, heaving did not appear
to have hindered mining operations.
1. Main Entries:
Two main line developments exist at this mine. Both started at the mine production shaft with one (the 1 east main) advanced eastward approximately 1.5 miles, and the other (1 west main) advanced westward approximately 1.75 miles. Each of these developments started as an eight-entry system consisting of four interior entries for fresh air, bordered by two exterior entries on each side for return air. The 1 east main was reduced to a seven-entry system using only three interior entries for fresh air, whereas the 1 west main carried eight entries its entire length.
The main line development was generally driven on 100 by 125 feet centers resulting in a total development width of 615 feet. Entries varied from 14 to 15 feet in width and eight to 10 feet in height. The main line development was designed to accommodate the mine's primary 48-inch belt conveyor, fresh and return air, power, materials, and access to all present and future working areas.
2. Submain Entries:
At the time of the accident, three submain developments had been driven and two more submain developments had been started. The five-entry system (three interior entries for fresh air bordered by one exterior entry on each side for return air), contained pillar sizes ranging from 90 by 62.5 feet to 90 by 125 feet and entry configurations 14 to 15 feet wide by 9 to 10 feet high. All submain developments were driven perpendicular north and south off the main line developments. Generally the submain developments were 375 feet wide and from 1 to 3 miles long. Submains were located with approximately 1 to 1.5 miles distance between them. As with the main line development, the submains accommodated a 48-inch conveyor belt, utilities, air, materials, and access to working panels.
3. Butt Entries:
Panel butts, or started entries, were driven from and perpendicular to (in an east-west fashion) the submain developments. The center of the submain pillar row was split in half to entry centers of 90 by 62.5 feet, the entire width of the submain development. At either side of the development, three entries (62.5 by 60 feet centers) were driven four crosscuts or 240 feet into the future panel development. Butts were placed on approximately 600-foot centers between both sides of the submain development.
Panel developments were driven on 55-foot centers from the submain butt entries using a three-entry system (two entries for fresh air and one for return air). The entries were 14 to 15 feet wide and 9 to 10 feet high. Pillar designs varied throughout the mine, but were more consistent in the north panel. Pillars in the southwest section were 12.5 feet to 18.5 feet wide and 80 to 90 feet in length.
Variations in pillar configurations in the southwest panel were due to different extraction patterns and ratios. Room lengths were approximately 250 feet. Panel developments were driven from 3,000 to 5,000 feet in length. Upon reaching the desired panel length, a bleeder system was established by developing a three-entry return system on 60 by 125 feet centers, connecting this system to a previous panel bleeder. The bleeder system paralleled the submain development and connected to the main line development.
Once the bleeder system was established, all three panel development entries were open to fresh air and panel retreat began. In all panel mining instances, barrier pillars were left for ground control.
In the southwest section of the mine, panels were developed off submains approximately 2,800 feet long and 500 to 600 feet wide. A set of three panel entries was driven down the center the full length of the panel to connect to bleeders at the west end.
These openings were driven 9 feet high and 15 feet wide at the center of the ovaloidal shaped opening. Intersections were enlarged by cutting off pillar corners to allow mining machines to turn into crosscuts and rooms. Pillars between the panel entries were approximately 40 by 47 feet.
Panel extraction rooms were driven off entries at right angles and were spaced to leave 12.5-foot wide pillars between rooms. Ventilation break-throughs left room pillars approximately 80 to 90 feet long. Only nominal barriers of unmined trona were left between panels for ventilation control.
Secondary ground support consisted of 5-foot long, 3/4-inch diameter, grade 60, fully grouted, resin bolts. Two bolts approximately 4 feet apart were installed across the opening and rows of bolts were spaced at 4 feet down the entry.
Additional bolts were used in widened-out areas at intersections.
No bolts were installed inby the first ventilation break-through
in the panel extraction room.
Primary ventilation was provided by a Jeffrey axial-vane exhausting fan with an identical fan as a back up. The fans were located on the surface adjacent to the ventilation shaft. This fan exhausted approximately 630,000 cubic feet per minute (cfm) from the mine.
In addition to the Jeffrey exhausting fan, a Buffalo Forge centrifugal fan was located adjacent to the production shaft.
This fan provided air for heating and did not add significant volume to the mine air flow.
Stoppings, overcasts, and regulators were used to control intake and return air throughout the mine. Stoppings were installed in crosscuts to separate fresh air from return air. In panel development areas, stoppings were constructed of pre-made metal pans set in a metal angle frame. Joints were sealed with tape and stopping-to-rock contact points were sealed with polyurethane foam. Doors were located every five crosscuts to access the mine return air system.
Overcasts were constructed of corrugated aluminum or galvanized steel frames that bolted together. Polyurethane foam was sprayed over the joints to provide a seal. Overcasts were placed at the main and submain air course junctions, roadways and belt drifts of panel developments.
Regulators in the panel stoppings were constructed of metal pan material. Plywood boards installed in a runner piece were used to regulate air flow. Regulators were installed within 1,000 to 2,000 feet of the last open crosscut in main and submain developments. In panel areas, regulators were located near the bleeders or submain returns.
Auxiliary fans were used in the mine with rigid or collapsible vent tubing to ventilate the face on advance and on retreat.
Approximately 30,000 cfm of air was provided to each active
section; 10,000 cfm across the last open crosscut, 2,000 cfm to
the working faces.
The mine's primary escapeway was from the working area access roadway into the main line roadway and to the main service hoist.
Secondary escape was by the main return air course or through a
door into the mine return air course to the air ventilation shaft
and escape hoist.
A dual communication system was used throughout the underground
areas. One system consisted of permissible pager type phones,
for communicating on site only. The other was a touch-tone
system capable of communicating both on and off site. Both
systems were capable of communicating with surface areas. The
hoist house utilized both systems and served as the emergency
contact for underground personnel. A hoist operator was on site
DESCRIPTION OF ACCIDENT
On the day of the accident the "D" crew entered the mine at 6:00 a.m., the normal day shift starting time. Five members of the "D" crew were assigned to work in the 1S-13W panel, which was located west of the one south submains at 86 crosscut. The crew consisted of the following persons:
Howard Dennison, Continuous Bore Miner Operator
Michael Anderson, Shuttle Car Operator (victim)
Daniel Jereb, Shuttle Car Operator
Donald Mattinson, Bolter Operator
Charles Sayles Jr., Panel Foreman
Sayles assigned duties to his crew in the panel and then went to the shop area near the main production shaft to obtain rib rollers. Work assignments consisted of bore mining in the No. 14 � face. Dennison operated the bore miner and Anderson operated a shuttle car transporting ore to a Stamler transfer unit located at the west end of the panel belt line. Daniel Jereb was to install water hose at the west end of the main entry. Mattinson was to install roof bolts in the west areas of the panel.
Work proceeded without unusual incident until 8:30 a.m., when the pillars failed suddenly and without warning over a large area.
The brunt of the failure was concentrated in the southwest panels of the mine where Sayles' crew was working. Pillar failure occurred throughout mined-out panels 2W through 12W, covering an area about 3,000 by 7,000 feet. Severe floor heaving, rib slabbing, and roof falls occurred in the 1S-13W panel working areas and entries. The duration of the event was five to six seconds; however, ground falls and rumblings continued for several hours thereafter. Although persons working underground experienced the effects in different degrees, the crew in the 1S-13W panel was most severely affected.
The air blast resulting from the collapse caused stoppings throughout the south areas of the mine to be blown out. Dense clouds of dust and high concentrations of gases were liberated.
Airflow in the production shaft was reversed for about 17 minutes, totally disrupting the ventilation system.
Dennison stated that he experienced severe upward and downward movement in the cab of the bore miner as the floor heaved violently in the No. 14 � face. He was bounced against the cab roof. Rib and roof material fell on top of and around the machine. After the ground movement subsided, Dennison called out to Anderson who had been operating the shuttle car parked behind the bore miner. According to Dennison, Anderson replied that he was all right. Dennison's feet were pinned by falling material and he asked Anderson to obtain help. Dennison then fell unconscious for a short period of time. After regaining consciousness he was unable to see because of the dust that had been created. A short time later visibility improved and he began to move. His movement caused the seat to break, freeing his legs. After remaining in the bore miner for a short time he began to leave the area to try to get out of the mine.
Due to falls of ground in the crosscut, Dennison crawled toward the main entryway. As he progressed, more ground falls were encountered which covered his legs on two occasions, but he was able to free himself and continue. According to Dennison, he also encountered areas which were impassable and had to change his route. Dennison continued until he reached 13 and 14 crosscuts in the main entryway where the roof bolter was parked.
He went around the bolter and backtracked to the belt entry, then down the entry to 12 crosscut and south to the main entryway.
When again in the main entryway he saw the LHD loader and called out to anyone who might be in the area. He was answered by Mattinson, who had lost his cap lamp and was injured.
Just prior to the accident Mattinson had driven the loader to the main entryway, 11 crosscut in 1S-13W, to obtain roof bolts.
After parking the loader, he walked to the supply trailer containing roof bolts and then returned to the loader. The massive pillar failure occurred as Mattinson approached the loader.
Mattinson stated that falling material struck him on the head, knocking him down and covering his legs. His hardhat and cap lamp were dislodged causing him to be in total darkness. He suffered an injury to his head and blood ran into his eyes.
Unaware of the extent of damage in the mine, he assumed that this was the only area affected. Due to the injury to his leg, he first decided to remain where he was and wait for help. However, rocks began falling around him and he was afraid that the intersection might collapse. He crawled around and located his hardhat but could not find his cap lamp. He continued crawling and came to a rib where he stopped to rest. A short time later, Mattinson crawled toward what he thought was a belt line entry. He encountered large piles of rock in several places. At one point a falling rock struck his chest and stomach. After freeing himself, he crawled to a nearby stub entry, which he thought would be more stable and sat with his back between the face and rib. While resting he thought he sensed stagnant air and became concerned about suffocation. He heard what sounded like blasts or explosions, which were followed by what he perceived to be massive roof falls in the distance. He decided to wait until the ground activity settled before attempting to leave the area.
According to Mattinson, as he waited in the stub, he saw Dennison's light at the face area and called out. Dennison joined him at the stub and Mattinson asked where Anderson and Jereb were located. Dennison stated that he thought they may have been buried by the continuing ground falls. The two men debated whether to remain in the area or attempt to make their way to the production shaft. Mattinson, with the help of Dennison, found his cap lamp and was able to use it by switching to the bulb's spare filament in the lamp unit. They decided to leave the panel and called out to anyone who may have been within hearing distance, but no one responded. When they approached the No. 8 crosscut lunch site, they heard a voice on the mine page phone. Michael McCann, mine superintendent, was talking on the phone from the main shop. Mattinson conversed with McCann and informed him of their location. They learned that Sayles had safely reached the main shop and requested help in locating Anderson and Jereb. Gas readings taken by Mattinson in the lunch niche indicated that an explosive concentration of methane was present. After completing the call with McCann, Mattinson and Dennison walked out of the panel to the submains roadway then proceeded north toward the production shaft. As they proceeded, they encountered substantial amounts of stopping material that had been blown out and was littering the roadway. Mattinson stated that breathing was difficult during the walk and gas readings taken along the way indicated continuous explosive levels of methane. The smell of ammonia was strong.
Although littered with debris, roadways were generally intact and passable. They continued walking north until they met Frank Obrocta, production area supervisor, who was accompanied by McCannand Sayles. Mattinson briefly conferred with Sayles about the conditions in the 1S-13W panel and the stopping debris encountered in the roadway. Mattinson and Dennison then continued to the production shaft, then on to a nearby area known as the "high bay" where they and other injured miners received first aid treatment. They were transported to the surface at approximately 11:30 a.m. Injured employees were transported by ambulance to a hospital in nearby Rock Springs, where they were treated and released.
When the massive pillar failure occurred, Daniel Jereb was hanging water hose at the intersection of the main entry and No.14 crosscut in the 1S-13W panel. Jereb said that he heard a loud explosion followed by a fall of ground in the area where he was standing and he was pushed against the rib. After a short period of time the material stopped falling and the ground movement eased. He remained standing against the rib and saw Michael Anderson approaching. Anderson told Jereb that Dennison was trapped in the bore miner at the No. 14 � crosscut face. The two men walked to the face through the caved rock debris and found the bore miner and Anderson's shuttle car under a substantial amount of fallen rock. They called out and looked for Dennison but could not find him. Due to the condition of the mine air and caving roof, they decided to leave the panel. Since they had encountered extensive caving when traveling the normal route to the face, they decided to travel out one of the other entries to exit the panel.
According to Jereb, exiting from the area was slow and difficult due to caving and the presence of methane, ammonia, and dust. As they traveled, they checked several long rooms for an exit to the main entry but the caving was too extensive. They stopped to rest and decided to put on their self-rescue devices which they carried on their belts. Anderson stated that he could not continue due to dizziness and shortness of breath. After resting, Jereb helped Anderson move to other areas in search of better air. The moves were of short distances and better air was not found. Anderson's strength deteriorated to a point where he could no longer communicate or sit up according to Jereb.
Jereb, responding to Anderson's failing condition, decided that he must get help. Traveling through bad air, caved areas and debris, he reached the No. 8 crosscut lunch site at the main entry. Jereb located his water jug and then traveled north on the 1S roadway toward the production shaft. As he neared the No. 53 crosscut, he encountered Rhone-Poulenc's (white) mine rescue team which was progressing south. The team checked and debriefed him and then moved him to the fresh air base where first aid was administered. He was then taken to the production shaft and transported to the surface. He was taken to the hospital in Rock Springs by ambulance where he was treated for dehydration and mine gas exposure and then released. Jereb's rescue occurred at 5:38 p.m. on February 4, 33 hours after the pillar failure.
In debriefing Jereb, the rescue team learned of Anderson's last known location and began a concerted effort to reach him. Their progress was slowed due to explosive levels of methane encountered as the teams advanced. Most of the ventilation stoppings in the southwest panel had been blown out and reconstruction was necessary in order to dilute the methane gas to nonexplosive levels. Anderson remained where Jereb had left him, which was at the No. 9 crosscut between the 9 and 9 � long rooms in the middle curve of the 1S-13W panel. The Solvay Silver mine rescue team reached the long rooms from the return entry and saw Anderson's light at 5:32 a.m. on February 5. The team captain spoke to Anderson while the area was being ventilated prior to reaching him, but Anderson did not answer. He responded by moving his light occasionally, but never spoke. Anderson sat up momentarily and then fell back. The team reached him and fitted him with a self-contained breathing apparatus. Anderson was placed on a back board stretcher and transported from the panel on a hand cart. Cardiopulmonary resuscitation was administered continuously during the evacuation process.
Anderson was taken to the panel entrance at 6:54 a.m., where an Emergency Medical Technician from Rhone-Poulenc's mine rescue team was standing by. He was then taken to the production shaft and brought out of the mine at 7:34 a.m. An ambulance transported Anderson to the hospital in Rock Springs where he was pronounced dead on arrival at 8:07 a.m. Death was attributed to asphyxia due to inhalation of ammonia and carbon dioxide.
Although employees in the 1S-13W panel were subjected to the
brunt of the collapse, employees in other areas of the south,
east, and center sections of the mine also experienced severe
ground movement, dust, and gas liberations. Eight employees in
these other areas required medical treatment for eye and lung
irritation due to dust and gases.
Both rescue teams from the Solvay mine were activated within the
first half hour following the event. Upon receiving word, the
other four trona mining companies located within the county
offered the services of their rescue teams. Initially only the
teams from Tg (Texasgulf) and Rhone-Poulenc were asked to
respond. Later, teams from FMC and General Chemical mines were
also asked to assist.
MSHA was initially notified on February 3, by Solvay Minerals that a seismic event had occurred which affected the mine and that two employees were unaccounted for. MSHA inspector, Danny Frey, of the Green River, Wyoming, field office, immediately began to monitor the situation. Additional MSHA personnel were dispatched to the mine and a command center was established to coordinate recovery efforts. As rescue efforts intensified, MSHA personnel monitored the operations around the clock.
Concurrent with rescue and recovery efforts at Solvay, MSHA
assigned a team from its technical support group to evaluate
similarities of conditions and mine design at all other trona
operations in the area. The team concluded that a similar
occurrence at these other mines was not likely due to differences
in mine designs and geological strata. The geological strata is
discussed at Appendix 6.
The collapse of the entire southwest section of the Solvay mine was of unprecedented magnitude and destruction. The occurrence registered 5.1 Richter Magnitude throughout the Western United States. Initially the event was thought to be an earthquake because of its intensity; however, MSHA has concluded that analysis of seismic data indicates a collapse mechanism rather than a normal tectonic earthquake. It was a consensus opinion, after months of extensive investigation by Solvay personnel, technical experts retained by Solvay, U.S. Bureau of Mines and MSHA, that a cascading pillar failure, "domino failure", or very rapid progressive pillar collapse was the most likely mechanism to explain the event. Several possible causes of the pillar collapse have been studied. MSHA concludes that the loss of pillar strength over a period of time was due to rock material weaknesses and stresses. Eventually, many pillars became so weak that a massive failure occurred. The alternative theories for the cause of pillar collapse, not ranked in order of likelihood, are as follows:
Failure of the large barrier pillar between the 1S-7W and 1S-8W panels. This failure overloaded the nearby panel pillars and caused their rapid deterioration.
Sudden failure of overburden strata above the southwest panels. Failure of this pressure arch led to overload and destruction of the panel pillars throughout the southwest section of the mine.
A large gas pocket or gas reservoir collapsed underneath part of the southwest panels. Again, pillars were overloaded and failed throughout the southwest part of the mine.
Detailed technical evaluations and assessments of the likelihood of each summary cause and trigger mechanism can be found in MSHA's Technical Support report of this accident, which is included at Appendix 6.
Solvay officials initiated various measures to prevent recurrence of the February 3 event. A long-term revision of the mine design will be finalized upon completion of all investigations, tests, and reports. In the interim, the following changes in mine design have been incorporated to ensure ground stability:
retreat rooms have been shortened in length to provide larger barrier pillars between panels;
crosscut centers have been increased from 55-foot centers to 65-foot centers to create larger pillars;
the overall panel extraction rate has been decreased from 62% to 56%;
a 250-foot barrier pillar will be left in the southeast part of the mine.
SEQUENCE OF EVENTS
February 3, 1995
Friday, 6:00 and 8:00 a.m. - Employees began their shifts.
(54 miners underground)
8:26 a.m. - Seismic event occurs. Surface employees heard a loud explosion-type sound and felt significant shaking.
8:30 a.m. - The mine power was deenergized and the hoist house established as the initial command center.
8:43 a.m. - Local, State and MSHA offices were notified of the problem.
Underground personnel received instructions to report to the "high bay" as the mine was being evacuated.
10:00 a.m. - All persons accounted for except for five employees working at 1S-8E and four employees working at 1S- 13W production panels.
11:00 a.m. - Command center was established in the office of the mine's safety director, Joseph Vendetti.
11:30 a.m. - First skip arrived on the surface with injured employees. Injured employees taken to Rock Springs Hospital.
12:06 p.m. - Fifty-two employees accounted for and taken out of the mine.
2:40 p.m. - Underground rescue efforts were initiated and the two Solvay teams entered the mine. A fresh air base was established at the "high bay". Teams were instructed to determine the volume of air coursing through the critical splits underground and then examine ventilation devices on both the north and south sides of the west mains out to the intersection of 1N submains, 1S submains and the west mains. Damage to critical stoppings was encountered and repairs began immediately.
4:30 p.m. - Maintenance personnel went into the mine to determine the extent of damage to the service hoist and initiate repairs so the hoist could be used.
4:50 p.m. - The second fresh air base was established at No. 8W.
6:10 p.m. - Teams began to explore 1S submain. One team examined the west side ventilation stoppings and the other team examined the east side ventilation stoppings. The teams were instructed to stop exploration when 3 percent (3%) methane was encountered.
6:30 p.m. - Donald Stauffenberg, Wyoming state mine inspector, arrived at the mine site.
7:55 p.m. - Solvay's mine rescue teams were relieved by two teams from Tg. One team from Rhone-Poulenc went underground to serve as back up at the fresh air base.
8:25 p.m. - Robert M. Friend, MSHA Rocky Mountain district manager, and Tom Koenning, MSHA DS&H Technology Center in Denver, Colorado, arrived.
9:58 p.m. - The service hoist was repaired and placed into service.
10:07 p.m. - A tremor was felt on surface which was believed to be caused by an after shock.
10:59 p.m. - The two Tg teams repaired ventilation stoppings at the intersection of 1S submains, 1N submains and the west mains. The team began to explore the 1S submains where they encountered 4 percent (4%) methane ahead of the ventilation stoppings they had repaired.
February 4, 1995
Saturday, 12:20 a.m. - Teams were encountering 6 percent (6%) methane at 8S.
1:30 a.m. - Crews of Solvay miners went into the mine to construct Kennedy stoppings behind mine rescue teams who were installing curtains sealed with foam. These crews were working in fresh air which had been established through the ventilation repair efforts of the mine rescue teams.
3:00 a.m. - Rhone-Poulenc teams detected 13 percent (13%) methane at the two entries connecting 1E panel to the main return at crosscut Nos. 6W and 7W. Because of the 13 percent (13%) methane, teams were instructed to build stoppings in 11W and 12W entries at 7 's.
4:48 a.m. - Teams worked on restoring ventilation at 12S.
5:00 a.m. - MSHA technical support personnel arrived with an infrared unit to continuously monitor methane and carbon monoxide levels at the main exhaust fan. Fan monitoring crews began to report water gauge readings from the fan.
5:15 a.m. - Air readings taken across the entries going south indicated approximately 100,000 cfm going into 1S submains.
8:00 a.m. - Experienced an air flow problem into the 1S submains - appeared to be a blockage where air coursed from the west mains across the top of the overcasts.
8:36 a.m. - The stoppings line between 15 and 16W in entries 1, 2, 3, and 4N were extended to direct exhausting air from 1S submain to the north side of the west mains.
The change was completed at 8:56 a.m., and ventilation improved measurably.
10:24 a.m. - Teams were working on restoring stoppings at 21S.
11:35 a.m. - Teams were exploring to 28 south. Temporary curtains were installed at 23S. Kennedy stoppings used to replace curtains were installed to 16S on the west side and 1E bleeders were curtained off on the east side.
12:07 p.m. - Air readings taken at 24 's across all entries of 1S submains totaled 305,100 cfm going into 1S submain. Kennedy stoppings had been installed to 18S. Curtains were hung at the mouth of 2E bleeder.
12:23 p.m. - Fresh air base established at 18S.
1:04 p.m. - Curtains installed to 29S, Kennedy stoppings installed to 24S.
1:42 p.m. - Teams began to scale bad ground as conditions began to worsen in 36S.
2:43 p.m. - Curtains installed to 37S on the west side and to 4E bleeder on the east side. Air readings at 37 's revealed 236,798 cfm down 1S submain.
3:10 p.m. - Fresh air base extended to 23S.
4:20 p.m. - Curtains were installed to 41S on the west side.
5:01 p.m. - Five (5) east bleeder was curtained off. West side curtains were installed to 45S. Kennedy stoppings behind them were installed to 33S. Air readings at 41 's revealed 267,855 cfm into 1S submain.
5:35 p.m. - Rhone-Poulenc White team spotted a light. Dan Jereb was in the intake entry (15W) walking towards them. They estimated that Jereb was at approximately 53S. The rescue team at that time was standing at 47S. They met a few moments later at 51S. Methane at that location was 11%, oxygen was 17.2%. Jereb was placed on a stretcher, given oxygen and brought out of the mine. After arriving on the surface he stated that Michael Anderson was alive when he left him approximately two hours before; however, Jereb appeared to have a very poor concept of time. He had no idea that he had been underground for approximately 33 hours.
6:30 p.m. - Fresh air base moved to 45S.
7:58 p.m. - Temporary stoppings installed to 55S on the west side.
8:05 p.m. - Four teams were now in the mine, one team for exploration, two teams for stopping construction, and one team on standby. Four-team rotation was worked throughout the remainder of the rescue and recovery efforts.
8:50 p.m. - Curtains were installed to 59S on the west side, 7E bleeders were curtained off loosely to allow some air to bleed through.
9:05 p.m. - Fresh air base extended to 50S.
9:25 p.m. - Teams reported very little air flow at the end of the curtain line at 61S.
10:20 p.m. - Twelve percent methane was measured at 62S. Curtains were discovered to be down at the mouth of 7E bleeders and air short-circuiting at that point. Repairs were started.
11:20 p.m. - Stoppings at the mouth of the 7E bleeders were repaired and methane at crosscuts 62 and 63 had cleared.
11:38 p.m. - Four and one-half percent methane was detected at 67S.
February 5, 1995
Sunday, 12:00 a.m. - Methane measurements at the mouth of the 8E panel ranged between 2 and 2.6%.
12:12 a.m. - One of the curtains failed at the mouth of 4E bleeders.
1:08 a.m. - Stoppings were installed to 73S on the west side utilizing two teams to construct ventilation stoppings and one team to explore.
1:26 a.m. - Stoppings installed up to 76S on the west side. Teams had explored to 81S. Methane at that point was 3.5%.
1:38 a.m. - Stoppings installed up to 80S. Methane at 81S was 3%.
1:47 a.m. - Stoppings installed up to 81S on the west side - methane at crosscut 83 was 2.8%.
1:53 a.m. - Fresh air base was moved to 70S.
2:05 a.m. - Teams reached the mouth of 1S-13W panel. Methane at 85S was 5.8%.
2:12 a.m. - Curtain at 85S was completed. Methane in 16W entry was 4.5%, oxygen was 19.2%.
2:20 a.m. - Tg Gold team explored up to 1 crosscut in 13W. Methane was 7% and oxygen was 19.9%.
2:57 a.m. - Rescue teams reported erratic conditions inby No. 4 crosscut. Teams encountered caved material and slabs, which were scaled.
3:00 a.m. - Tg Gold team reached 7 crosscut and measured 2.2% methane.
3:02 a.m. - Tg Gold team reached the lunch niche at 8 crosscut in the intake entry. Oxygen was 16%, with a strong ammonia smell and the team went under oxygen.
3:12 a.m. - Tg Gold team reached the electrical transformer at 9 crosscut.
3:25 a.m. - Tg Gold team reported hearing what sounded like moans ahead of them and worked toward the sounds. They were in the belt entry at 6 crosscut at 3:28 a.m. and again heard what sounded like moans.
4:25 a.m. - Fresh air base was moved to 76S.
4:35 a.m. - Command center spoke directly with the captains of Rhone-Poulenc Blue team and Solvay Silver team with instruction on how to further explore 1S-13W panel.
5:00 a.m. - Solvay Silver team and Rhone-Poulenc Blue team traveled to 9 crosscut in the return entry where they would split up to explore each long room up to the middle curves.
Rhone-Poulenc Blue team worked outby and Solvay Silver team worked inby.
5:32 a.m. - Solvay Silver team spotted Anderson's light in the long room straight up from the Stamler at 9 crosscut.
Ventilation curtains were installed to clear explosive levels of methane from the long room.
6:20 a.m. - After the methane level had decreased to 3.5%, the team proceeded toward Anderson.
6:23 a.m. - The Solvay Silver team placed an apparatus on Anderson in the middle curve of 9 crosscut.
6:36 a.m. - Anderson was loaded onto a back board stretcher.
6:59 a.m. - The rescue team performed CPR on Anderson. An EMT was dispatched from the command center and entered the mine with a defibrillator to meet teams bringing Anderson out of the mine.
7:15 a.m. - Rescue teams arrived at the fresh air base with Anderson. Life Flight was notified.
7:34 a.m. - Anderson was placed on the cage and hoisted to the surface.
7:40 a.m. - Anderson was transported by ambulance from the mine site to a hospital in Rock Springs.
8:07 a.m. - Anderson was pronounced dead on arrival at the hospital.
Respectively submitted by:
Supervisory Mine Safety and Health Inspector
Mine Safety and Health Inspector
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