Mine Blasting Safety: Decades of Progress

Harry Verakis and Thomas Lobb U.S. Dept. of Labor, MSHA, Technical Support

Abstract

Blasting accident data over a 30-year period (1980-2010) are summarized and presented for all types of surface and underground mining operations in the USA. The historical record of injuries from blasting accidents in all types of mines continues to show a significant decline. The overall decline in mine blasting injuries in the U.S.A. has resulted from advancements in blasting technology, training and improvements in blasting products and blasting processes. Some of the technology advancements such as safer blasting agents and computerized bulk vehicle loading, electronic detonators and remote operated blasting systems, and computerized blast design have and continue to significantly contribute to improvements in the historical blasting safety record. Also, the progress of si gnificantly improving the safety of mine blasting has resulted from the combined efforts of miners, mine companies and operators, miners, unions, explosive and blasting product manufacturers, associations such as the International Society of Explosives Engineers and the Institute of Makers of Explosives and various government agencies.

The blasting accident data were examined and analyzed to identify the primary causes, injuries and the historical trend. The cause or the activity that took place when the blasting accident occurred was separated into categories such as blast area security and misfires. The review of historical blasting accidents over the past 30 year s indicates where the record stands and the progress in improving safety. The presentation of blasting accident data is also provided to emphasize the continuing need for safe blasting practices and the challenges faced such as the need to further improve blast area security and to further reduce the safety hazard created by flyrock. Also important to the continual progr ess in mine blasting safety is education and training, the development of improved technology, and the observance of Federal, State, and local requirements for mine blasting operations

Introduction

Notwithstanding the fact that many billions of pounds of explosives and blasting agent have been used by the mining industry, the accident safety record has improved significantly in the past 30 years. Over the past 10 years, approximately 5 billion pounds of explosives and blasting agents were used annually in the United States. In 2010, the U.S. mining industry used 88.4 percent of the industrial explosives and blasting agents manufactured for commercial use. Figure 1 depicts the industrial use of explosives and blasting agents by percentage for 2010. Surface coal mining consumed 71 percent of the total amount of commercially produced blasting agents and explosives in 2010. Surface coal mining consumed approximately two-thirds of the annual average of 5.1 billion pounds of explosives commercially produced in the USA over the past decade. Surface coal mining continues to be the dominant user of blasting agents. In 2010, metal and nonmetal mining, including quarrying consumed about 17 percent of the total

Copyright © 2012 International Society of Explosives Engineers
2012G - Mine Blasting Safety: Decades of Progress 1 of 11commercial production of explosives and blasting agents. In 2010, Wyoming, West Virginia, and Kentucky accounted for 63 percent of the total consumed for coal production. Blasting agents and oxidizers represented 99 percent of the total of commercial explosives produced for use in 2010. The use of industrial explosives and blasting agents in 2010 was compared to industrial use that occurred three decades earlier in 1980. Figure 2 show the commercial usage of explosives and blasting agents in 1980. In a three decade period, surface coal mining use of blasting agents and explosives increased about 12.5 percent from 1980 to 2010. Metal mining and quarry and nonmetal mining use of blasting agents and explosives decreased about 5 to 5.5 percent from 1980 to 2010.

The use of permissible explosives in underground coal and gassy mines in 2010 declined 39 percent from 2009 to a level of 2,182, 574 pounds [Explosives, August 2010]. This level of use represents a decline of over 90 percent over the past three decades (1978-2010). The extraction of coal in underground mines by the use of permissible explosives has almost been replaced by the use of longwall and continuous mining methods.

The historical record of blasting accidents in all types of mines continues to show an overall decline in fatalities and injuries. The overall decline of injuries from mine blasting accidents in the USA in the past 30 years has resulted from advancements in blasting safety and training, as well as improvements in technology and blasting products. The significant decline in fatalities and injuries from mine blasting accidents is a result of the combined efforts and the accomplishments of mining companies and operators, miners, unions, explosive manufacturers and suppliers, explosive and blasting associations such as the International Society of Explosives Engineers and the Institute of Makers of Explosives and government agencies. Many mining companies have improved safety and training programs and continue to place emphases on blasting safety in their mining operations. Also, explosive and other manufacturers continue to develop and offer products to industry such as el ectronic detonator systems, computerized blast design, and laser profiling which are products to improve blasting safety.

The blasting accident data for all mining operations were examined and analyzed to identify the primary causes, injuries and the historical trend over the past three decades. The cause or the activity that took place when the blasting accident occurred was separated into categories such as blast area security and misfires. The review of historical mine blasting accidents indicates where the safety record stands from 1978 though 2010 and the progress in improving safety. The review of mine blasting accidents is intended to emphasize the continuing need for safe blasting practices, education, development of improved t echnology, and the observance of Federal, State, and local requirements for mine blasting operations.

Causes of mine blasting accident injuries

Table 1 shows the historical categorization of blasting accident injuries for coal and metalnonmetal mine operations for over three decades from 1978-2010. The blasting accident data were categorized according to the cause of the accident or activity that occurred when the accident happened. The major categories are: (1) blast area security, (2) flyrock, (3) premature blast, (4) misfires, (5) fumes, (6) transporting explosives, (7) disposing, (8) miscellaneous and

Copyright © 2012 International Society of Explosives Engineers
2012G - Mine Blasting Safety: Decades of Progress 2 of 11(9) surface accident at an underground mine.

As shown in Figure 3, the primary cause of almost 50 percent of all mine blasting accidents are attributed to blast area security, while flyroc k (11.8 percent) ranked second and premature blast (11.5 percent) ranked a very close third with misfires at fourth (9.3 percent). Fumes from blasting represented 8.6 percent of the causes of all mine blasting accidents. These five causes of blasting accidents represent 90 percent of all types of mine blasting accidents. As indicated in Table 1, underground coal and underground metal-nonmetal operations combined represent 60 percent of the total mine blasting accidents involving fatalities and injuries.

Both recently and historically, blast area security and flyrock (surface mining operations) continue to be the two primary causes of mine blasting accidents. As shown in Table 1 and Figure 3, blast area security and flyrock represented 61 percent of all mine blasting accidents. It is apparent there is a continuing need to address and emphasize blast area security and the hazards of flyrock to further reduce blasting accidents and injuries. An examination of the
factors to determine the bounds of the blast area and the measures to secure the blast area have been published with ways to mitigate incidents [Bajpayee, Verakis, Lobb, 2005]. More recently, mine blasting accidents were addressed on the c ontinuing safety hazard of flyrock [Verakis, 2011].

Analysis of mine blasting accident data [1]

A compilation and review of coal and metal/ nonmetal mine blasting accident from 1978 through 2010 was made to identify the primary causes, injuries and the historical trend. Table 2 lists the blasting accident fatalities for all mining operations from 1978 through 2010. The blasting accident data in Table 2 are listed separately for surface coal mining, surface metal-nonmetal mining, underground coal and underground metal-nonmetal mining.

An analysis and comparison of mine blasting accident data is shown in Table 3 in four-year periods from 1978-2009 for coal and metal-nonmet al mining operations. The blasting accident data for surface coal mines indicate a combined total of 212 injuries occurred for the period from 1978 through 2010 compared to 415 injuries for underground coal mines as shown in Table 3. Of this total as shown in Table 2, there were 22 fatalities in surface coal mines and 32 fatalities in underground coal mines. The trends as shown in Table 2 and Table 3 are a significant decrease in the number of fatalities and injuries from blasting accidents for surface and underground coal mines.

An analysis and comparison of accident data was also made for metal-nonmetal mines. The
accident data in Table 3 for surface metal-nonmetal mines indicate a combined total of 266 injuries occurred for the period from 1978 through 2010 compared to 291 injuries for underground metal-nonmetal mines. Of this total as shown in Table 2, there were 26 fatalities in surface metal-nonmetal mines and 29 fatalities in underground metal-nonmetal mines. The trends as shown in Table 2 and Table 3 are a significant decrease in the number of fatalities and injuries from blasting accidents for surface and underground metal-nonmetal mines.

Copyright © 2012 International Society of Explosives Engineers
2012G - Mine Blasting Safety: Decades of Progress 3 of 11The trend from 1978 through 2010 has been a continuing and significant decrease in fatalities and injuries from mine blasting accidents. As i ndicated in Table 4, combining the accident data in four-year increments from 1978-2009 for all mine blasting accidents show the significant decrease by a large percentage. The percentage went from 36.4 to 2 percent of the total number of fatalities and injuries from 1978 through 2009. In fact, for all mining operations except for surface metal-nonmetal mining there was only one blasting-related fatality each in surface coal, underground coal and underground metal-nonmetal mining in an 11-year period from 2000 through 2010. No blasting-related fatality has occurred in surface metal-nonmetal mining in an 11-year period from 2000 through 2010. This is a very significant achievement in the reduction
of fatalities.

Revisiting a recent fatal accident

A revisit of a more recent blasting accident that resulted in a fatality in an underground metal mine highlights the continuing need to address and improve blasting safety. There had been no fatality involving blasting in an underground metal-nonmetal mine since 1993. The fatality occurred on May 28, 2010, during a blasting operation at an underground gold mine located near the Forks of Salmon, California [Fitch, James, et. al. 2010]. The victim had 20 years of mining experience. Another miner with 20 years of mining experience was also injured in the blasting accident. On the day of the accident, the face of a drift was drilled, loaded and detonated. The two miners waited about 15 to 20 minutes before reentering the blast area. The two miners discussed that the blast did not sound right. When the two miners were about 20 to 25 feet from the face area, several of the still loaded holes detonated. Both miners were struck by broken rock and debris from the blast. An ANFO blasting agent used in the blast had an expired shelf life and sat for a long period of time in moist conditions. A delayed detonation occurred and the two miners were struck by rock and the concussion from the blast. Mine management knew the requirements if explosive material is suspected of burning at the blast site, were aware of multiple recent failures at this mine of charges to explode when expected, were aware of an obvious and improper audible report from this blast, and had reason to suspect burning explosives at the blast site, yet failed to ensure that miners waited the proper period of time before returning to the area [Fitch, James, et. al. 2010]. The accident occurred because management failed to ensure that policies and procedures to protect miners in blast areas were followed. The procedures did not ensure that miners did not return to the blast site for at least one hour after the suspected burning stopped.

After this paper was prepared another fatal blasting accident occurred on September 7, 2011, at an underground gold mine operation in Juneau County, Alaska. Details of the accident are not available at this time. However, preliminary information will be posted on MSHA’s website, www.msha.gov as it becomes available and a report on the accident will be prepared by MSHA and also posted after completion of its accident investigation.

Summary

Copyright © 2012 International Society of Explosives Engineers
2012G - Mine Blasting Safety: Decades of Progress 4 of 11Reports and more details on blasting accidents from 1995 to the present may be found on MSHA’s Internet Site at http//:www.msha.gov under Fatalgrams/Reports. Also, MSHA’s blasting regulations for underground coal mines, Part 75, Subpart N–Explosives and for underground metal-nonmetal mines, Part 57, Subpart E and Subpart T-Explosives may be found on MSHA’s Internet Site under Compliance Assist ance, Statutory and Regulatory Information, Title 30, Code of Federal Regulations (30 CFR).

This summary of blasting accident data can be used to more effectively respond to the challenges that affect the mining industry in the effort to ensure and improve blasting safety. Even though fatalities and injuries from mine blasting accidents continue to decline, miners and personnel employed by the mining industry continue to suffe r fatal and disabling injuries from blasting accidents. The blasting and explosives industry and their associated organizations, along with labor and Government agencies have made great progress in making blasting safe in the mining industry. Today, there is more awareness about the need to address safety in all mine blasting operations. A constant vigilance, a high degree of awareness and prudent efforts are needed to continue the decline of blasting accidents in the U.S. mining industry. As a reminder there is no place for complacency in any mine blasting operation. Each and every blast must be conducted with vigilance and attention. Each and every blast is not routine. Once complacency starts a blasting issue or incident will occur somewhere down the road. Stringent measures must continue to be taken to maintain good blasting practices and to avert blasting accidents. The lofty goal of zero injuries will not be reached if complacency is allowed to occur.

MSHA is committed to conferences, such as held by the International Society of Explosives Engineers, in which industry and industry a ssociations, labor, management, government, and academia join to share their experiences and work toward common goals of improving blasting safety. MSHA will continue to emphasize blasting safety and the reduction in mine blasting accidents, and to be involved in the mining community and public segments that address explosives and blasting safety.

Footnote

1 Due to incomplete recording information some earlier accidents could not be categorized as accurately as desired resulting in some tabulation differences.

References

Bajpayee, T.S., Verakis, Harry, and Lobb, Thomas, 2005, “Blasting Safety: Revisiting Site Security,” Proceedings of the 31st Annual C onference on Explosives and Blasting Technique, Orlando, Florida.

Siskind, David E. and Kopp, John W., 1995, “Bla sting Accidents in Mines, A 16-Year Summary”, Proceedings of the 21st Annual Conference on Explosives and Blasting Technique, International Society of Explosives Engineers, Vol. II, pp. 224-239.

Verakis, Harry and Lobb, Thomas, 2006 “An Examin ation of Mine Blasting Accidents Over a

Copyright © 2012 International Society of Explosives Engineers
2012G - Mine Blasting Safety: Decades of Progress 5 of 11Quarter of a Century,” Proceedings of the 32nd Annual Conference on Explosives and Blasting Technique, Dallas, TX

Verakis, Harry, 2011, “Flyrock: A Continuing Blas t Safety Threat,” Proceedings of the 37th Annual conference on Explosives and Blasting Technique, San Diego, CA

Fitch, James, Breland, Brad and Lobb, Thomas , 2010, MSHA Accident Investigation Report, Fatal Explosives Accident, Discovery Day Mine, Gold run Enterprises LLC, Forks of Salmon, Siskiyou County, California, May 28, 2010, 8 pages.

MSHA Accident Data Abstracts, Underground a nd Surface Mine Blasting Fatal and Nonfatal Accident Reports, 1978-2010.

“Explosives”, U.S. Geological Survey, Minerals Yearbook, 2010.

“Explosives, Annual”, U.S. Geological Survey, Mineral Industry Surveys, revised October 1981.

Copyright © 2012 International Society of Explosives Engineers
2012G - Mine Blasting Safety: Decades of Progress 6 of 11Table 1--Causes of fatal plus nonfatal in juries from blasting accidents in mining, Figure 2 - Explosives & Blasti ng Agents Consumption in 1980

Total of 4

, 274

, 462

, 000 p ounds ( 1

, 938

, 866 metric tons )

Coal mining
58.6%

Quarry & nonmetal

minin

14.6 Metal mining

13.1% Constructio

9.7 A ll othe r
4 Total of 5

, 908

, 381

, 600 p ounds ( 2

, 680

, 000 metric tons )

Coal mining
71%

Quarry & nonmetal

minin

9 Metal mining

8 Constructio

9 A ll othe r
3 Figure 1 - Explosives & Blasti ng Agents Consumption in 2010

Copyright © 2012 International Society of Explosives Engineers
2012G - Mine Blasting Safety: Decades of Progress 7 of 111978-2010

Cause Surface
M-NM Surface
Coal Underground
M-NM Underground Coal Total Percent

Blast area security 97 95 76 315 583 48.91

Flyrock 80 61 0 0 141 11.83
Premature
blast 37 34 52 14 137 11.49

Misfires 26 10 50 25 111 9.31
Fumes 0 0 82 21 103 8.64 Transporting explosives 0 0 11 0 11 0.92

Disposing 3 2 2 0 7 0.59
Miscellaneous 26 10 18 30 84 7.05
Surface Accident@ Underground
Mine 0 0 5 10 15 1.26

Total 269 212 296 415 1192 100.00
Percent 22.57 17.79 24.83 34.82 100.0

Table 2 – Blasting Acci dent Fatalities, 1978-2010 Copyright © 2012 International Society of Explosives Engineers
2012G - Mine Blasting Safety: Decades of Progress 8 of 11Table 3 – Historical decline in fatalities and injuries for coal and Year Coal Metal-Nonmetal

Under- Surface Under- Surface Total

ground ground

1978 3 0 5 2 10

79 0 2 5 0 7

80 7 1 5 2 15

81 3 2 5 3 13

82 3 1 2 2 8

83 0 0 0 0 0

84 1 1 1 3 6

85 6 0 0 0 6

86 0 3 1 0 4

87 0 1 0 0 1

88 2 0 0 0 2
89 0 2 1 3 6
90 3 1 0 2 6
91 1 2 2 0 5
92 0 1 0 3 4
93 0 1 1 0 2
94 0 1 0 2 3
95 0 0 0 1 1
96 0 0 0 1 1
97 1 0 0 1 2
98 1 0 0 0 1
99 0 2 0 1 3

2000 0 0 0 0 0

01 0 0 0 0 0

02 0 0 0 0 0

03 1 0 0 0 1

04 0 0 0 0 0

05 0 0 0 0 0

06 0 0 0 0 0

07 0 1 0 0 1

08 0 0 0 0 0
09 0 0 0 0 0

10 0 0 1 0 1
Total 32 22 29 26 109

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2012G - Mine Blasting Safety: Decades of Progress 9 of 11metal-nonmetal surface and unde rground mine blasting accidents

Period Coal Surface Coal Underground M-NM Surface M-NM Underground Total (fatalities & injuries)

1978-81 62 (29.2%) 173 (41.7%) 59 (22.2%) 137 (47.1%) 431

1982-85 33 (15.6%) 90 (21.7%) 43 (16.2%) 40 (13.8%) 206

1986-89 48 (22.6%) 77 (18.6%) 45 (16.9%) 45 (15.5%) 215

1990-93 28 (13.2%) 44 (10.6%) 40 (15.0%) 28 (9.6%) 140

1994-97 17 (8.0%) 13 (3.1%) 34 (12.8%) 22 (7.6%) 86

1998-2001 8 (3.8%) 10 (2.4%) 20 (7.5%) 9 (3.1%) 47

2002-05 10 (4.7%) 4 (0.96%) 18 (6.8%) 3 (1.0%) 35

2006-09 6 (2.8%) 4 (0.96%) 7 (2.6%) 7 (2.4%) 24

Totals 212 415 266 291 1184
2010 0 in 2010 0 in 2010 2 in 2010 5 in 2010 7 in 2010

Table 4 – Historical decline in fatalit ies and injuries for all mine blasting
accidents combined

Period Total (fatalities & injuries) Percentage

1978-81 431 36.4

1982-85 206 17.4

1986-89 215 18.2

1990-93 140 11.8

1994-97 86 7.3

1998-2001 47 4.0

2002-05 35 3.0

2006-09 24 2.0

Totals 1184 100

2010 7 ---

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2012G - Mine Blasting Safety: Decades of Progress 10 of 11Figure 3 – Causes of fatalities plus injuries fo r all mine blasting accidents combined, 1978-2010

0.5 0.9 8.6 9.3

11.5 11.8 48.9

8.3 Misc. including
surface accident at undergrd. mine Transporting explosives Fumes Misfires Premature blast Blast area security

1978 - 2010 Flyrock

Disposal

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2012G - Mine Blasting Safety: Decades of Progress 11 of 11