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Direct coal liquefaction safety risks: Feedstock production and transportation
Enrw Vol IO. No. 7. pp. 877~Mb. Pnnted in Great Bnmn.
19X5
o~ho-s44?/Xc 63.00 i 1985 Pergamon Pren
,x1
I td
DIRECT COAL LIQUEFACTION SAFETY RISKS: FEEDSTOCK PRODUCTION AND TRANSPORTATION-t
Health
A. P. WATSON and F. R. O’DONNELL and Safety Research Division, Oak Ridge National Laboratory. TN 3783 I, U.S.A. (Received
10 August
Oak Ridge,
1984)
Abstract-We identify major factors resulting in serious injury and loss of life during coal mining and shipment necessary to supply a hypothetical I-quad/yr direct coal liquefaction industry with feedstock and fuel. Regional siting of direct coal liquefaction processing facilities, mine type. and coal transport mode would all govern the magnitude of deaths and injuries occurring as a consequence of commercial liquefaction. Of the five coal supply regions evaluated, the most serious occupational hazards would be generated by underground mining in the Central Appalachian Basin. The least hazardous mining regions are predicted to be the Powder River and Northern Great Plains Basins. Truck transport of coal in either the Northern or Central Appalachian basins was determined to generate the greatest risk of employee fatalities and lost workdays: barging on Appalachian or mid-western waterways is Ieast hazardous to workers. Public risks for fatal injury accidents via rail or truck transport are comparable for all regions except the Illinois Basin, which would generate approximately half the risk of the other four regions. The risks of injury and death to workers and the public during these first segments of the fuel cycle are greater than any other risks attributable to direct liquefaction commercialization.
I
INTRODUCTION
The Office of Health and Environmental Research of the U.S. Department of Energy (U.S. DOE) supports assessments of oil shale, direct and indirect coal liquefaction, and coal gasification technologies in the belief that systematic analysis of potential risks in emerging energy technologies identifies major hazard factors that could be mitigated prior to full-scale development. This paper, which is derived from analyses performed during one of these broad-scale studies,’ provides a systematic safety risk assessment of the hazards associated with feedstock production and transportation necessary to supply a hypothetical, I-quad/yr direct coal liquefaction industry in the U.S. (l-quad z 1 X 10i5 Btu). These first segments of the direct liquefaction fuel cycle have heretofore received only cursory appraisal since they are common to many industries. Our studies indicate that, under present operating conditions, the majority of deaths and injuries attributable to direct liquefaction commercialization would occur during coal mining and shipment. Further, our analysis will demonstrate that the magnitude of risks is region-specific and could be reduced. Direct liquefaction of coal is a process of synthetic fuel production in which pulverized coal is reacted under pressure with a hydrogen donor and steam in the presence of a solvent derived from the process to produce a low sulfur and low ash liquid fuel. For the purpose of evaluating coal production and transportation risk, each of the three principal direct liquefaction process designs [Solvent Refined Coal (SRC), Exxon Donor Solvent (EDS), and H-Coal] was considered an individual variation of a generic process. A I-quad/yr industry would require several plants sited at feasible locations throughout the United States. The assessment’ met this requirement by siting two, O.l-quad plants at each of five locations selected on the basis of their proximity to coal fields, transportation routes, and waterways of sufficient size to receive potentially significant quantities of liquid effluents. The five sites chosen include: (1) Illinois (drained by the Ohio and Mississippi Rivers)-Breckinridge/Lewisport, Kentucky (37”52’ lat.. 86”55’ long.); (2) Central Appalachia (drained by the Monongahela and Mississippi Rivers)-Morgantown/ Easton, West Virginia (39”37’ lat., 79”57’ long.): (3) Powder River (drained by the Little t Research under contract
sponsored by the Office of Health and Environmental Research. 1J.S. Department of Energy DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc. !C U.S. Government. 877
A. P.
878
WATSON and F. R. O’DONNELI
Powder, Little Missouri, and Mississippi Rivers)-Gillette/Adon, Wyoming (44” 3 1’ lat., 105” 16’ long.); (4) Northern Great Plains (drained by the Missouri and Mississippi Rivers)-Bismarck/Wilton, North Dakota (47”07’ lat., lOO”55’ long.); (5) Northern Appalachia (drained by the Susquehanna River to Chesapeake Bay at Perryville, Maryland)-Scranton/Black Walnut, Pennsylvania (41”35’ lat., 76”55’ long.). Each site is located within, or is easily accessible to, a major coal basin of the U.S. (see Fig. 1). These sites were chosen for the purpose of estimation only and do not represent the siting decision of any current or future synfuel production firm. Locations of the reference process at these separate sites allows some flexibility in estimating the range of impacts of a l-quad liquefaction industry. Based on engineering analysis of the three basic process designs, each O.l-quad unit is estimated to consume approximately 2.0 X lo4 tons of coal per day to produce 5.0 X lo4 barrels (bbl) of liquid fuels and hydrocarbon gases daily. By assuming 330 operating days per year, we estimated that each 0. l-quad unit would consume 6.6 X lo6 tons of coal and produce 1.6 X 10’ bbl of fuel and gases per year. 2. COAL EXTRACTION 2.1. Mortality and lost workdays The mining of coal has long been known to involve a high risk of mortality, lost-time injuries, and lost workdays.2 However, the risk is not uniform throughout the United States, but varies with region and mine type. Data necessary to calculate the magnitude of occupational risk to surface and underground miners employed in every domestic coal basin (Fig. 1) have been compiled annually since 1978 by the Mine Safety and Health Administration (MSHA) of the U.S. Department of Labor. These observations (approximately 232,000), presently available via an on-line information system,3 were summarized by coal basin to derive mean fatality and lost workday (LWD) injury and LWD rates per lo6 tons coal mined by surface or underground methods for the years 1978-1980 (Table 1). Thus, the absolute values are normalized and permit inter-regional comparison. The frequency and severity of reported accidents is highly specific to the region and mine type involved. For example, over 85% of all fatalities, LWD injuries and lost workdays reported during 1978-1980 occurred in underground mines; over 76% of all deaths and LWD injuries occurred in Appalachian mines alone (Table 1). Annual average surface and underground coal production were calculated for each coal basin during the 1978-1980 time period (Table 2). As shown in Table 2, the
Fig. 1. Location
of generic
direct
liquefaction facilities areas) in the United
(triangles) States.
and major
coal basins (shaded
Direct coal liquefaction Table
879
safety risks
1. Mean fatality, lost workday (LWD) injury and LWD rates per lo6 tons of coal produced in five coal basins given as an annual average for the 3-year period 1978-1980 (X f SE).
0.52 (3.06) 0.13
55 A3 (23.14, 10.65
NM = no mining; there was no commercially mined underground Northern Great Plains or Powder River Basins between 1978 and 1980.
coal produced
in the
Northern Great Plains and Powder River Basins derived no coal from underground mines during 1978-1980; underground production in the other three basins ranged from 46.3 to 64.3% of the total tonnage extracted per basin. The quantities of underground- and surface-mined coal consumed by each 0. I-quad/yr plant at a site were estimated by multiplying annual consumption (6.6 X lo6 tons) by the average fraction of underground and surface mine production for each associated coal basin (Table 2). All coal consumed at a plant was assumed to be extracted from its associated coal basin. Estimates of the expected number of annual fatalities, LWD injuries and LWDs suffered by mine workers producing coal required by each plant were obtained by multiplying the quantities of underground- and surface-mined coal consumed by the appropriate fatality, LWD injury, and LWD rates provided in Table 1. The resulting projections are given in Fig. 2(a)-(c) for a single O.l-quad/yr plant at each site. The greatest occupational hazard would be associated with coal extracted by underground mining for a Central Appalachian plant. The numbers of underground fatalities (2.2), LWD injuries (235.2), and LWDs (6388.4) are the highest of those estimated for all individual plants and dominate the combined Central Appalachia risks for surface Table 2. Annual average coal production by mine type in five coal basins, 1978-1980 (X f SE). The value in brackets is the portion of regional production provided by surface or underground mining.
A. P. WATSON and F. R. O’DONNELL
880
..
1
UNDERGROUND MINE! 5
SURFACE
STANDARD
NM
NORTHERN APPALACHIA
CENTRAL APPALACHIA
ILLINOIS
NO
I
MINES
ERROR
-I
MINES
NORTHERN GRT PLAINS
(a>
_____._._ UNDERGROUND
SURFACE
NO
S
MINES
STANDARD
NM
MINE
.._
ERROR
MINES
i
NM
NORTHERN APPALACHIA
CENTRAL APPALACHIA
ILLINOIS
NORTHERN GRT PLAINS
1
NMI*; POWDER RIVER
(b> Fig. 2. Estimated annual fatalities, lost workday (LWD) injuries, and lost workdays (LWD) among mine workers supplying coal to a 0. lquad plant at each site for (a) fatalities per plant by region (Northern Appalachian and Powder River surface fatalities SE = O.O), (b) LWD injuries per piant by region.
and underground mining, i.e. 2.5 fatalities, 260.3 LWD injuries, and 6943.4 LWD. Combined surface and underground coal production for the Northern Appalachian and Illinois sites are predicted to result in one excess death per basin per year. However, coal production to supply a Northern Appalachian plant would result in nearly twice as many LWDs as would the same production supplying an Illinois plant (6435.2 vs. 3432.1 LWD). The fewest occupational hazards are associated with surface-mined coal supplied to the Powder River and Northern Great Plains plants, with only 0.04 fatalities and less than 1000 LWDs between them.
Direct coal liquefaction safety risks
881
SURFACE
MINES
STANDARD
NM
NO
ERROR
MINES
NM$1 NORTHERN APPALACHIA
CENTRAL APPALACHIA
ILLINOIS
NORTHERN GRT PLAINS
i
POWDER RIVER
cc>
Fig. 2. (c) LWD per plant by region.
2.2. Risk factors Detailed analyses of 1980 accident data have permitted characterization by principal cause of fatal and LWD accidents in surface and underground mines.4 Out of the 32 possible identifiers used by MSHA to classify accident causation, the few clarified below most clearly describe the circumstances directly contributing to the bulk of mine accident risk. 2.2.1. Fatalities. The leading causes of accidental death during 1980 were roof-falls (33.0%), powered haulage (22.3%), machinery (12.8%), and electrical equipment (10.6%) for underground mines in all regions. Fatalities in these four categories comprised 78.7%, of the total lives lost in underground accidents. Surface miners, who are not working in the close confines of an underground shaft. are usually thought to be exposed to quite different hazards than their deep-mine colleagues. However, there are more similarities than contrasts when major causes of fatal accidents are compared. After summing over all regions, we have determined that collapse of the working face or falling ore from the non-working highwall accounted for 30.4% of all surface mine fatalities in 1980; powered haulage equipment was involved in another 30.4%; while machinery was cited in 2 1.7% of the reports. Thus, the three major causes of accidental death are virtually identical for underground and surface mine types. 2.2.2. L WD injuries. The major causes of LWD accidents are similar in all underground mines, regardless of region. Materials handling (33.5%), powered haulage (14.1%). machinery ( 14.1%). and slips and falls of personnel (12.2%) lead all other factors when values are summed across regions. However, accident severity, measured in average days lost per accident, is greatest during slides or collapse of the roof, ribs, or working face (mean of 43.6 LWD for fall of the face in the Appalachian Basin and 59.3 LWD for falling rock in the Illinois Basin). The most severe lost-time injuries are usually the least common. The operation of surface mines in all regions is apparently similar enough that major causal factors are identical for this form of coal extraction as well. It comes as no surprise that slips and falls of personnel are the leading causes of injury (29.6%) since employees must frequently traverse unstable and/or slippery work surfaces. Materials handling closely follows in frequency (25.7%). These two factors are cited in over 55% of the total observations for all regions. Machinery (12.8%) and powered haulage (12.2%) comprise
A. P. WATSON and F. R. O’DONNELL
882 Table
3. Average
annual
occupational
injury
rates for truck, c0al.t
rail, and
water
transportation
of
I. t Derived
from rates in reference
5.
most of the remainder. The most severe injuries were produced by gas/dust ignition (5 1.8 LWD and 66.6 LWD averaged for the Appalachian and Illinois Basin mines, respectively; Northern Great Plains and Powder River Basin mines did not report this cause). 3.
COAL
TRANSPORTATION
Accidents occurring as a consequence of transporting coal from mines or processing facilities to a direct liquefaction plant can result in injuries to both employees of the transportation industry and members of the public who travel on, cross, work, or dwell near transport routes. Most public injuries occur as the result of railway grade crossing or truck-car collisions. Annual average occupational fatality and injury rates per tonmile derived from data of the U.S. Department of Labor and Transportation are presented in Table 3. The three modes by which coal is usually moved are rail, truck, or barge. Truck haulage is the most hazardous transportation mode in all categories (fatalities, serious injury cases, and lost workdays); barge movement over inland waterways is the least hazardous. In the following estimate of transportation risk, we assumed that any location within the coal basin was equally likely to be chosen as the point of origin for coal shipment (the fledgling synfuels industry has not yet specified coal deposits within each basin that would be the most probable sources of feedstock coal). Proximity to coal supplies is a major factor in site selection for the following reasons: (1) transportation costs need to be kept at a minimum in order to maintain competitive product prices; (2) one purpose of coal liquefaction development is to generate “clean” energy from coals that are unsuitable for direct use because of high ash or sulfur content. Such coals are at slight demand in today’s market place and can be purchased at relatively low prices. It would be false economy to construct a liquefaction facility where such coals were not locally abundant, Thus, our transportation assessment did not consider importation of coals to each generic site from mines outside each basin. Since the actual mines that will supply feedstock coal are unknown, actual rail, truck, and barge routes are also unknown. Thus, to estimate transportation hazards, we calculated ranges of transportation route distances that encompass the mileage between each plant site and both nearest and farthest points on the perimeter of its associated coal basin (see Table 4). Route lengths were estimated with the INTERLINE (barge and rail) and HIGHWAY (interstates, U.S. highways, and principal state highways) computer codes.6,7 The databases used by both codes are essentially road atlases of domestic highways, rail lines, and navigable waterways. By assuming that all coal required by any single plant (6.6 X lo6 tons per year) was transported entirely by one of the three modes examined and multiplying the limiting distances between plant site and each coal basin perimeter (Table 4) by the mean injury rates presented in Table 3, the numbers of potential fatalities and
Direct coal liquefaction safety risks
883
Table 4. Ranges of one-way distances (miles) between generic plant sites and the perimeter of their associated coal basins. Trlnaport Option(ta,lr,.,
1--------
injuries to transport workers were estimated. Public risk was estimated as a ratio of occupational risk for rail and truck transport. Information necessary for an estimate of public risk to barge traffic was unavailable: data supplied by the U.S. Coast Guard, which reports accidents involving vessels, does not include incidents involving the general public.*-l3 Summary values are presented in Tables 5 and 6. By whatever mode, transportation to the Northern and Central Appalachian sites appears to produce the greatest number of fatalities among employees and the public when compared to estimates derived for the other three locations. Within these two highrisk regions, extensive use of truck transport accounts for most of the severe employee injuries, while rail transport accounts for most of the fatal injury accidents to the public. Barge transportation cannot be considered an option for the Northern and Powder River sites where the Missouri River is not navigable most of the year. There are no major differences in the numbers of occupational and public injuries from truck or rail movement for these two sites. Transportation risks for the Illinois Basin location are considered the least hazardous of the five regions evaluated. 4. DISCUSSION
AND
CONCLUSIONS
A summary of risks estimating total impacts of a full-scale, 1-quad/yr direct coal liquefaction industry appears in Walsh et al.’ (see Table 7). Projections of safety risk to coal miners and haulers were derived from existing data. Comparable estimations of biological effects resulting from workplace and public exposures to synfuels effluents are difficult to derive due to data limitations involving dose response to organic chemicals, lack of occupational statistics, etc. Although imprecise, estimates of worker and public mortality illustrate the high potential for effects specifically attributed to operation of synfuel facilities. Given the uncertainties of the projections in Table 7, coal development will be the principal cause of death and injury associated with direct coal liquefaction under the most favorable circumstances (i.e. when the low range of risks is reflected in operating conditions). If the upper range of risks is achieved in all portions of the direct coal development could generate fatalities liquefaction fuel cycle simultaneously, (n = 64) approaching that produced by maximum occupational carcinogen exposure (n = 100). The synfuel industry could reduce coal transportation hazards by siting liquefaction plants near mine entrances, thus reducing the amount of coal haulage, or making maximum use of barge transport in the Appalachian and Illinois Basins. Additionally, the use of dedicated unit trains traveling only to and from the mine and processing facility and requiring infrequent car coupling/uncoupling, would generate fewer accidents than the use of many, mixed-commodity trains following undedicated routes. Improvements could also be made by the coal extraction industry. Principal causes of accidental death in both underground and surface mines (i.e. collapse of the roof or highwall) are largely outside the control of the individual miner. Mining is by definition an extractive process, and coal mining removes a mechanical support which must be replaced to prevent collapse. The work areas closest to the working face are well known to be the most hazardous. Provisions of the Federal Coal Mine Health and Safety Act of 1969, and its amendments in 1977, called for roof support plans to be designed and tailored for each underground mine. The accident data indicate that either the plans or
River
0.1-0.4 ----
18.1-106
68.0-113.3
32.2-62.2
60.7-131.7
16.4-139.9
C.Wll
Injury
Serious
R9il
.O
227.3-1328.7
852.4-1420.7
403.2-779.2
760.4-1650.7
959.4-1154
__--
LWD$
.a
t It is assumed that the plant consumes 20,000 tons/day, 330 days/yr. $ Lost workdays.
Powder
Pl ainr
0.2-0.4
Great
Nor thsrn
0.2-0.4
0.3-0.5
Fatalities
F
0.1-0.2
Appalachia
Appelacbia
site
Illinois
Central
Northern
Plant
_ l-
0.4-1.2
1.0-l
0.5-0.9
1.0-l
1.1-1.9
Fatalities
.4
.9
Trllck
57 .s-155.2
131.5-194.5
60.8-127
141.4-255.2
149.7-261.9
Inj WY c.ses
Serious
Transportation
.l
option
__
1036.5-2800.5 --
2371.9-3508.0
1096.3-2292.2
2551.3-4604.3
2700.8-4723
---
-
.S
-
NA
NA
0.04-0.1
0.1
0.02
Fatalities
Table 5. Estimated annual average numbers and types of occupational accidents due to transportation of coal from coal basins to each associated direct liquefaction plant.?
NA
NA
3.0-7.5
8.1
2.1
Gales
Inj llry
Serious
Barge
NA
NA
70.7-175.5
167.5
48.0
Direct coal liquefaction safety risks
885
Table 6. Estimated annual number of fatal injury accidents to the public resulting from coal transport to each generic direct liquefaction plant.? ____~ _____ Tr.n.*ort.t10* 0pti0,n PI*nf site
t It is assumed that the plant consumes 20,000 tons/day, 330 daysfyr. Data necessary for estimating public risks from barge traffic are not reported by the U.S. Coast Guard. $ Based on calculated national ratio of non-employee fatalities to rail industry employee fatalities = 12.9.*-‘* 0 Based on calculated national ratio of non-truck occupant fatalities to truck occupant fatalities = 2.04.8-‘3 (Non-truck occupants include motorists and their passengers as well as pedestrians.)
their implementation are inadequate to solve the problem. It is also clear that effective plans for the support of highwalls and unstable piles of ore or spoil need to be developed for surface mines. Powered haulage operations and machinery were also significant (approximately 25% of total for surface and underground) causes of mortality. In most incidents, the mine equipment involved was designed to meet a specific production need; safety considerations for the operator were often secondary. Many miners consider improper equipment design and maintenance to be principal factors in accidents involving machinery. The need for improvements is obvious. Major machinery design changes that miners would welcome include better visibility, standardization among manufacturers for placement of machinery controls, roll bars and shielding roofs as standard equipment, and guards over moving parts. If materials handling and personnel fall accidents (which accounted for nearly 50% of all lost-time accidents in both mine types) could be controlled, LWD injuries would be reduced dramatically. Such a decrease in injury rates would represent a tremendous saving in down-time. Muscle strains are involved in the majority of materials handling cases, and are considered to be the result of lifting an excessively heavy load. Concrete
Table 7. Estimated annual excess mortality and injury due to supply and operation of a l-quad direct coal-liquefaction industry.t
t Reference 1. $ Defined as lost workday or serious injuries. $ Injury assessment for public coal transportation performed due to lack of recent source data.
plus facility construction and operation not
886
A. P. WATSONand F. R.
O’DONNELL
blocks, roof bolts, electrical cable, etc., must be moved during mining operations; all too often transport is performed by hand. Not only is this a primitive method, but it also places undue strain on the spine and the rest of the body. Major improvements are needed here. In contrast, falls are often due to poor visibility while walking on a littered work surface. Better lighting, non-skid soles on safety shoes, and changes in hard hat design to improve visibility should be attainable and could reduce the observed number and severity of slips and falls. If powered haulage and machinery accidents could be reduced as well, approximately 75% of all LWD injuries would be under control. REFERENCES I. P. J. Walsh, E. D. Copenhaver, C. F. Baes, 111,E. E. Calle, E. Dixon, C. S. Dudney, E. L. Etnier, R. A. Faust, J. F. V-Fischer, G. D. Griffin, G. A. Holton, T. D. Jones, P. Mason, S. J. Niemczyk, F. R. O’Donnell, J. G. Pruett, R. Shor, S. P. N. Singh, M. Uziel and A. P. Watson, “Health and Environmental Effects Document on Direct Coal Liquefaction-1982. Vol. I, Assessment; Vol. 2, Appendices”, Oak Ridge National Laboratory Report ORNL/TM-8624/Vl and ORNL/TM-8624/V2, Oak Ridge, TN (1983). 2. B. L. Cohen and I-S. Lee, Hlth Phys. 36, 707 (1979). 3. A. P. Watson, T. E. Birchfield and C. S. Fore, “Risk Assessment of Coal Production: An Information Systems User’s Manual”, Oak Ridge National Laboratory Report ORNL/TM-842 I, Oak Ridge, TN (October 1982). 4. A. P. Watson, “Factors Affecting Lost-Time and Fatal Injury Incidence in U.S. Coal Mines”, Oak Ridge National Laboratory Report ORNL/PPA-83/7, Oak Ridge, TN (June 1983). 5. F. R. O’Donnell and H. C. Hoy, “Occupational and Safety Data and Casualty Rates for the Coal Fuel Cycle”, Oak Ridge National Laboratory Report ORNL/TM-8442, Oak Ridge, TN (in review). 6. E. L. Hillsman, P. E. Johnson and B. E. Peterson, “Predicting Routes of Radioactive Wastes Moved on the U.S. Railroad System”, PATRAM 80. Proceedings, 6th International Symposium on Packaging and Transportation of Radioactive Materials (Edited by H. W. Hubner), Vol. I, pp. 359-366. International Congress Center, West Berlin (1980). 7. D. S. Joy, P. E. Johnson, D. B. Clarke and S. C. McGuire, “Predicting Transportation Routes for Radioactive Wastes”, Presented at the ANS Topical Meeting, Waste Management ‘81: Waste Isolation in the U.S. and Elsewhere, Technical Program and Communication, Vol. 1, pp. 415-425, Tucson, Arizona (I98 1). 8. U.S. Department of Transportation, “Transportation Safety Information Report”, 4th Quarter Highlights and Summary, USDOT, Transportation Information Division (1976). 9. U.S. Department of Transportation, “Transportation Safety Information Report”, October, November, and December, NTISUB/C/224-004, USDOT (I 977). IO. U.S. Department of Transportation, “Transportation Safety Information Report”, Annual Summary (March), NTISUB/D/224-004, USDOT (1979). 1I. U.S. Department of Transportation, “Transportation Safety Information Report”, October, November, and December, NTISUB/D/224-004, USDOT (1978). 12. U.S. Department of Transportation, “Transportation Safety Information Report”, October, November, and December, NTISUB/D/224-004, USDOT (1979). 13. U.S. Department of Transportation, “National Transportation Statistics”, DOT-TSC-RSPA-79- 19, USDOT (1979).
19X5
o~ho-s44?/Xc 63.00 i 1985 Pergamon Pren
,x1
I td
DIRECT COAL LIQUEFACTION SAFETY RISKS: FEEDSTOCK PRODUCTION AND TRANSPORTATION-t
Health
A. P. WATSON and F. R. O’DONNELL and Safety Research Division, Oak Ridge National Laboratory. TN 3783 I, U.S.A. (Received
10 August
Oak Ridge,
1984)
Abstract-We identify major factors resulting in serious injury and loss of life during coal mining and shipment necessary to supply a hypothetical I-quad/yr direct coal liquefaction industry with feedstock and fuel. Regional siting of direct coal liquefaction processing facilities, mine type. and coal transport mode would all govern the magnitude of deaths and injuries occurring as a consequence of commercial liquefaction. Of the five coal supply regions evaluated, the most serious occupational hazards would be generated by underground mining in the Central Appalachian Basin. The least hazardous mining regions are predicted to be the Powder River and Northern Great Plains Basins. Truck transport of coal in either the Northern or Central Appalachian basins was determined to generate the greatest risk of employee fatalities and lost workdays: barging on Appalachian or mid-western waterways is Ieast hazardous to workers. Public risks for fatal injury accidents via rail or truck transport are comparable for all regions except the Illinois Basin, which would generate approximately half the risk of the other four regions. The risks of injury and death to workers and the public during these first segments of the fuel cycle are greater than any other risks attributable to direct liquefaction commercialization.
I
INTRODUCTION
The Office of Health and Environmental Research of the U.S. Department of Energy (U.S. DOE) supports assessments of oil shale, direct and indirect coal liquefaction, and coal gasification technologies in the belief that systematic analysis of potential risks in emerging energy technologies identifies major hazard factors that could be mitigated prior to full-scale development. This paper, which is derived from analyses performed during one of these broad-scale studies,’ provides a systematic safety risk assessment of the hazards associated with feedstock production and transportation necessary to supply a hypothetical, I-quad/yr direct coal liquefaction industry in the U.S. (l-quad z 1 X 10i5 Btu). These first segments of the direct liquefaction fuel cycle have heretofore received only cursory appraisal since they are common to many industries. Our studies indicate that, under present operating conditions, the majority of deaths and injuries attributable to direct liquefaction commercialization would occur during coal mining and shipment. Further, our analysis will demonstrate that the magnitude of risks is region-specific and could be reduced. Direct liquefaction of coal is a process of synthetic fuel production in which pulverized coal is reacted under pressure with a hydrogen donor and steam in the presence of a solvent derived from the process to produce a low sulfur and low ash liquid fuel. For the purpose of evaluating coal production and transportation risk, each of the three principal direct liquefaction process designs [Solvent Refined Coal (SRC), Exxon Donor Solvent (EDS), and H-Coal] was considered an individual variation of a generic process. A I-quad/yr industry would require several plants sited at feasible locations throughout the United States. The assessment’ met this requirement by siting two, O.l-quad plants at each of five locations selected on the basis of their proximity to coal fields, transportation routes, and waterways of sufficient size to receive potentially significant quantities of liquid effluents. The five sites chosen include: (1) Illinois (drained by the Ohio and Mississippi Rivers)-Breckinridge/Lewisport, Kentucky (37”52’ lat.. 86”55’ long.); (2) Central Appalachia (drained by the Monongahela and Mississippi Rivers)-Morgantown/ Easton, West Virginia (39”37’ lat., 79”57’ long.): (3) Powder River (drained by the Little t Research under contract
sponsored by the Office of Health and Environmental Research. 1J.S. Department of Energy DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc. !C U.S. Government. 877
A. P.
878
WATSON and F. R. O’DONNELI
Powder, Little Missouri, and Mississippi Rivers)-Gillette/Adon, Wyoming (44” 3 1’ lat., 105” 16’ long.); (4) Northern Great Plains (drained by the Missouri and Mississippi Rivers)-Bismarck/Wilton, North Dakota (47”07’ lat., lOO”55’ long.); (5) Northern Appalachia (drained by the Susquehanna River to Chesapeake Bay at Perryville, Maryland)-Scranton/Black Walnut, Pennsylvania (41”35’ lat., 76”55’ long.). Each site is located within, or is easily accessible to, a major coal basin of the U.S. (see Fig. 1). These sites were chosen for the purpose of estimation only and do not represent the siting decision of any current or future synfuel production firm. Locations of the reference process at these separate sites allows some flexibility in estimating the range of impacts of a l-quad liquefaction industry. Based on engineering analysis of the three basic process designs, each O.l-quad unit is estimated to consume approximately 2.0 X lo4 tons of coal per day to produce 5.0 X lo4 barrels (bbl) of liquid fuels and hydrocarbon gases daily. By assuming 330 operating days per year, we estimated that each 0. l-quad unit would consume 6.6 X lo6 tons of coal and produce 1.6 X 10’ bbl of fuel and gases per year. 2. COAL EXTRACTION 2.1. Mortality and lost workdays The mining of coal has long been known to involve a high risk of mortality, lost-time injuries, and lost workdays.2 However, the risk is not uniform throughout the United States, but varies with region and mine type. Data necessary to calculate the magnitude of occupational risk to surface and underground miners employed in every domestic coal basin (Fig. 1) have been compiled annually since 1978 by the Mine Safety and Health Administration (MSHA) of the U.S. Department of Labor. These observations (approximately 232,000), presently available via an on-line information system,3 were summarized by coal basin to derive mean fatality and lost workday (LWD) injury and LWD rates per lo6 tons coal mined by surface or underground methods for the years 1978-1980 (Table 1). Thus, the absolute values are normalized and permit inter-regional comparison. The frequency and severity of reported accidents is highly specific to the region and mine type involved. For example, over 85% of all fatalities, LWD injuries and lost workdays reported during 1978-1980 occurred in underground mines; over 76% of all deaths and LWD injuries occurred in Appalachian mines alone (Table 1). Annual average surface and underground coal production were calculated for each coal basin during the 1978-1980 time period (Table 2). As shown in Table 2, the
Fig. 1. Location
of generic
direct
liquefaction facilities areas) in the United
(triangles) States.
and major
coal basins (shaded
Direct coal liquefaction Table
879
safety risks
1. Mean fatality, lost workday (LWD) injury and LWD rates per lo6 tons of coal produced in five coal basins given as an annual average for the 3-year period 1978-1980 (X f SE).
0.52 (3.06) 0.13
55 A3 (23.14, 10.65
NM = no mining; there was no commercially mined underground Northern Great Plains or Powder River Basins between 1978 and 1980.
coal produced
in the
Northern Great Plains and Powder River Basins derived no coal from underground mines during 1978-1980; underground production in the other three basins ranged from 46.3 to 64.3% of the total tonnage extracted per basin. The quantities of underground- and surface-mined coal consumed by each 0. I-quad/yr plant at a site were estimated by multiplying annual consumption (6.6 X lo6 tons) by the average fraction of underground and surface mine production for each associated coal basin (Table 2). All coal consumed at a plant was assumed to be extracted from its associated coal basin. Estimates of the expected number of annual fatalities, LWD injuries and LWDs suffered by mine workers producing coal required by each plant were obtained by multiplying the quantities of underground- and surface-mined coal consumed by the appropriate fatality, LWD injury, and LWD rates provided in Table 1. The resulting projections are given in Fig. 2(a)-(c) for a single O.l-quad/yr plant at each site. The greatest occupational hazard would be associated with coal extracted by underground mining for a Central Appalachian plant. The numbers of underground fatalities (2.2), LWD injuries (235.2), and LWDs (6388.4) are the highest of those estimated for all individual plants and dominate the combined Central Appalachia risks for surface Table 2. Annual average coal production by mine type in five coal basins, 1978-1980 (X f SE). The value in brackets is the portion of regional production provided by surface or underground mining.
A. P. WATSON and F. R. O’DONNELL
880
..
1
UNDERGROUND MINE! 5
SURFACE
STANDARD
NM
NORTHERN APPALACHIA
CENTRAL APPALACHIA
ILLINOIS
NO
I
MINES
ERROR
-I
MINES
NORTHERN GRT PLAINS
(a>
_____._._ UNDERGROUND
SURFACE
NO
S
MINES
STANDARD
NM
MINE
.._
ERROR
MINES
i
NM
NORTHERN APPALACHIA
CENTRAL APPALACHIA
ILLINOIS
NORTHERN GRT PLAINS
1
NMI*; POWDER RIVER
(b> Fig. 2. Estimated annual fatalities, lost workday (LWD) injuries, and lost workdays (LWD) among mine workers supplying coal to a 0. lquad plant at each site for (a) fatalities per plant by region (Northern Appalachian and Powder River surface fatalities SE = O.O), (b) LWD injuries per piant by region.
and underground mining, i.e. 2.5 fatalities, 260.3 LWD injuries, and 6943.4 LWD. Combined surface and underground coal production for the Northern Appalachian and Illinois sites are predicted to result in one excess death per basin per year. However, coal production to supply a Northern Appalachian plant would result in nearly twice as many LWDs as would the same production supplying an Illinois plant (6435.2 vs. 3432.1 LWD). The fewest occupational hazards are associated with surface-mined coal supplied to the Powder River and Northern Great Plains plants, with only 0.04 fatalities and less than 1000 LWDs between them.
Direct coal liquefaction safety risks
881
SURFACE
MINES
STANDARD
NM
NO
ERROR
MINES
NM$1 NORTHERN APPALACHIA
CENTRAL APPALACHIA
ILLINOIS
NORTHERN GRT PLAINS
i
POWDER RIVER
cc>
Fig. 2. (c) LWD per plant by region.
2.2. Risk factors Detailed analyses of 1980 accident data have permitted characterization by principal cause of fatal and LWD accidents in surface and underground mines.4 Out of the 32 possible identifiers used by MSHA to classify accident causation, the few clarified below most clearly describe the circumstances directly contributing to the bulk of mine accident risk. 2.2.1. Fatalities. The leading causes of accidental death during 1980 were roof-falls (33.0%), powered haulage (22.3%), machinery (12.8%), and electrical equipment (10.6%) for underground mines in all regions. Fatalities in these four categories comprised 78.7%, of the total lives lost in underground accidents. Surface miners, who are not working in the close confines of an underground shaft. are usually thought to be exposed to quite different hazards than their deep-mine colleagues. However, there are more similarities than contrasts when major causes of fatal accidents are compared. After summing over all regions, we have determined that collapse of the working face or falling ore from the non-working highwall accounted for 30.4% of all surface mine fatalities in 1980; powered haulage equipment was involved in another 30.4%; while machinery was cited in 2 1.7% of the reports. Thus, the three major causes of accidental death are virtually identical for underground and surface mine types. 2.2.2. L WD injuries. The major causes of LWD accidents are similar in all underground mines, regardless of region. Materials handling (33.5%), powered haulage (14.1%). machinery ( 14.1%). and slips and falls of personnel (12.2%) lead all other factors when values are summed across regions. However, accident severity, measured in average days lost per accident, is greatest during slides or collapse of the roof, ribs, or working face (mean of 43.6 LWD for fall of the face in the Appalachian Basin and 59.3 LWD for falling rock in the Illinois Basin). The most severe lost-time injuries are usually the least common. The operation of surface mines in all regions is apparently similar enough that major causal factors are identical for this form of coal extraction as well. It comes as no surprise that slips and falls of personnel are the leading causes of injury (29.6%) since employees must frequently traverse unstable and/or slippery work surfaces. Materials handling closely follows in frequency (25.7%). These two factors are cited in over 55% of the total observations for all regions. Machinery (12.8%) and powered haulage (12.2%) comprise
A. P. WATSON and F. R. O’DONNELL
882 Table
3. Average
annual
occupational
injury
rates for truck, c0al.t
rail, and
water
transportation
of
I. t Derived
from rates in reference
5.
most of the remainder. The most severe injuries were produced by gas/dust ignition (5 1.8 LWD and 66.6 LWD averaged for the Appalachian and Illinois Basin mines, respectively; Northern Great Plains and Powder River Basin mines did not report this cause). 3.
COAL
TRANSPORTATION
Accidents occurring as a consequence of transporting coal from mines or processing facilities to a direct liquefaction plant can result in injuries to both employees of the transportation industry and members of the public who travel on, cross, work, or dwell near transport routes. Most public injuries occur as the result of railway grade crossing or truck-car collisions. Annual average occupational fatality and injury rates per tonmile derived from data of the U.S. Department of Labor and Transportation are presented in Table 3. The three modes by which coal is usually moved are rail, truck, or barge. Truck haulage is the most hazardous transportation mode in all categories (fatalities, serious injury cases, and lost workdays); barge movement over inland waterways is the least hazardous. In the following estimate of transportation risk, we assumed that any location within the coal basin was equally likely to be chosen as the point of origin for coal shipment (the fledgling synfuels industry has not yet specified coal deposits within each basin that would be the most probable sources of feedstock coal). Proximity to coal supplies is a major factor in site selection for the following reasons: (1) transportation costs need to be kept at a minimum in order to maintain competitive product prices; (2) one purpose of coal liquefaction development is to generate “clean” energy from coals that are unsuitable for direct use because of high ash or sulfur content. Such coals are at slight demand in today’s market place and can be purchased at relatively low prices. It would be false economy to construct a liquefaction facility where such coals were not locally abundant, Thus, our transportation assessment did not consider importation of coals to each generic site from mines outside each basin. Since the actual mines that will supply feedstock coal are unknown, actual rail, truck, and barge routes are also unknown. Thus, to estimate transportation hazards, we calculated ranges of transportation route distances that encompass the mileage between each plant site and both nearest and farthest points on the perimeter of its associated coal basin (see Table 4). Route lengths were estimated with the INTERLINE (barge and rail) and HIGHWAY (interstates, U.S. highways, and principal state highways) computer codes.6,7 The databases used by both codes are essentially road atlases of domestic highways, rail lines, and navigable waterways. By assuming that all coal required by any single plant (6.6 X lo6 tons per year) was transported entirely by one of the three modes examined and multiplying the limiting distances between plant site and each coal basin perimeter (Table 4) by the mean injury rates presented in Table 3, the numbers of potential fatalities and
Direct coal liquefaction safety risks
883
Table 4. Ranges of one-way distances (miles) between generic plant sites and the perimeter of their associated coal basins. Trlnaport Option(ta,lr,.,
1--------
injuries to transport workers were estimated. Public risk was estimated as a ratio of occupational risk for rail and truck transport. Information necessary for an estimate of public risk to barge traffic was unavailable: data supplied by the U.S. Coast Guard, which reports accidents involving vessels, does not include incidents involving the general public.*-l3 Summary values are presented in Tables 5 and 6. By whatever mode, transportation to the Northern and Central Appalachian sites appears to produce the greatest number of fatalities among employees and the public when compared to estimates derived for the other three locations. Within these two highrisk regions, extensive use of truck transport accounts for most of the severe employee injuries, while rail transport accounts for most of the fatal injury accidents to the public. Barge transportation cannot be considered an option for the Northern and Powder River sites where the Missouri River is not navigable most of the year. There are no major differences in the numbers of occupational and public injuries from truck or rail movement for these two sites. Transportation risks for the Illinois Basin location are considered the least hazardous of the five regions evaluated. 4. DISCUSSION
AND
CONCLUSIONS
A summary of risks estimating total impacts of a full-scale, 1-quad/yr direct coal liquefaction industry appears in Walsh et al.’ (see Table 7). Projections of safety risk to coal miners and haulers were derived from existing data. Comparable estimations of biological effects resulting from workplace and public exposures to synfuels effluents are difficult to derive due to data limitations involving dose response to organic chemicals, lack of occupational statistics, etc. Although imprecise, estimates of worker and public mortality illustrate the high potential for effects specifically attributed to operation of synfuel facilities. Given the uncertainties of the projections in Table 7, coal development will be the principal cause of death and injury associated with direct coal liquefaction under the most favorable circumstances (i.e. when the low range of risks is reflected in operating conditions). If the upper range of risks is achieved in all portions of the direct coal development could generate fatalities liquefaction fuel cycle simultaneously, (n = 64) approaching that produced by maximum occupational carcinogen exposure (n = 100). The synfuel industry could reduce coal transportation hazards by siting liquefaction plants near mine entrances, thus reducing the amount of coal haulage, or making maximum use of barge transport in the Appalachian and Illinois Basins. Additionally, the use of dedicated unit trains traveling only to and from the mine and processing facility and requiring infrequent car coupling/uncoupling, would generate fewer accidents than the use of many, mixed-commodity trains following undedicated routes. Improvements could also be made by the coal extraction industry. Principal causes of accidental death in both underground and surface mines (i.e. collapse of the roof or highwall) are largely outside the control of the individual miner. Mining is by definition an extractive process, and coal mining removes a mechanical support which must be replaced to prevent collapse. The work areas closest to the working face are well known to be the most hazardous. Provisions of the Federal Coal Mine Health and Safety Act of 1969, and its amendments in 1977, called for roof support plans to be designed and tailored for each underground mine. The accident data indicate that either the plans or
River
0.1-0.4 ----
18.1-106
68.0-113.3
32.2-62.2
60.7-131.7
16.4-139.9
C.Wll
Injury
Serious
R9il
.O
227.3-1328.7
852.4-1420.7
403.2-779.2
760.4-1650.7
959.4-1154
__--
LWD$
.a
t It is assumed that the plant consumes 20,000 tons/day, 330 days/yr. $ Lost workdays.
Powder
Pl ainr
0.2-0.4
Great
Nor thsrn
0.2-0.4
0.3-0.5
Fatalities
F
0.1-0.2
Appalachia
Appelacbia
site
Illinois
Central
Northern
Plant
_ l-
0.4-1.2
1.0-l
0.5-0.9
1.0-l
1.1-1.9
Fatalities
.4
.9
Trllck
57 .s-155.2
131.5-194.5
60.8-127
141.4-255.2
149.7-261.9
Inj WY c.ses
Serious
Transportation
.l
option
__
1036.5-2800.5 --
2371.9-3508.0
1096.3-2292.2
2551.3-4604.3
2700.8-4723
---
-
.S
-
NA
NA
0.04-0.1
0.1
0.02
Fatalities
Table 5. Estimated annual average numbers and types of occupational accidents due to transportation of coal from coal basins to each associated direct liquefaction plant.?
NA
NA
3.0-7.5
8.1
2.1
Gales
Inj llry
Serious
Barge
NA
NA
70.7-175.5
167.5
48.0
Direct coal liquefaction safety risks
885
Table 6. Estimated annual number of fatal injury accidents to the public resulting from coal transport to each generic direct liquefaction plant.? ____~ _____ Tr.n.*ort.t10* 0pti0,n PI*nf site
t It is assumed that the plant consumes 20,000 tons/day, 330 daysfyr. Data necessary for estimating public risks from barge traffic are not reported by the U.S. Coast Guard. $ Based on calculated national ratio of non-employee fatalities to rail industry employee fatalities = 12.9.*-‘* 0 Based on calculated national ratio of non-truck occupant fatalities to truck occupant fatalities = 2.04.8-‘3 (Non-truck occupants include motorists and their passengers as well as pedestrians.)
their implementation are inadequate to solve the problem. It is also clear that effective plans for the support of highwalls and unstable piles of ore or spoil need to be developed for surface mines. Powered haulage operations and machinery were also significant (approximately 25% of total for surface and underground) causes of mortality. In most incidents, the mine equipment involved was designed to meet a specific production need; safety considerations for the operator were often secondary. Many miners consider improper equipment design and maintenance to be principal factors in accidents involving machinery. The need for improvements is obvious. Major machinery design changes that miners would welcome include better visibility, standardization among manufacturers for placement of machinery controls, roll bars and shielding roofs as standard equipment, and guards over moving parts. If materials handling and personnel fall accidents (which accounted for nearly 50% of all lost-time accidents in both mine types) could be controlled, LWD injuries would be reduced dramatically. Such a decrease in injury rates would represent a tremendous saving in down-time. Muscle strains are involved in the majority of materials handling cases, and are considered to be the result of lifting an excessively heavy load. Concrete
Table 7. Estimated annual excess mortality and injury due to supply and operation of a l-quad direct coal-liquefaction industry.t
t Reference 1. $ Defined as lost workday or serious injuries. $ Injury assessment for public coal transportation performed due to lack of recent source data.
plus facility construction and operation not
886
A. P. WATSONand F. R.
O’DONNELL
blocks, roof bolts, electrical cable, etc., must be moved during mining operations; all too often transport is performed by hand. Not only is this a primitive method, but it also places undue strain on the spine and the rest of the body. Major improvements are needed here. In contrast, falls are often due to poor visibility while walking on a littered work surface. Better lighting, non-skid soles on safety shoes, and changes in hard hat design to improve visibility should be attainable and could reduce the observed number and severity of slips and falls. If powered haulage and machinery accidents could be reduced as well, approximately 75% of all LWD injuries would be under control. REFERENCES I. P. J. Walsh, E. D. Copenhaver, C. F. Baes, 111,E. E. Calle, E. Dixon, C. S. Dudney, E. L. Etnier, R. A. Faust, J. F. V-Fischer, G. D. Griffin, G. A. Holton, T. D. Jones, P. Mason, S. J. Niemczyk, F. R. O’Donnell, J. G. Pruett, R. Shor, S. P. N. Singh, M. Uziel and A. P. Watson, “Health and Environmental Effects Document on Direct Coal Liquefaction-1982. Vol. I, Assessment; Vol. 2, Appendices”, Oak Ridge National Laboratory Report ORNL/TM-8624/Vl and ORNL/TM-8624/V2, Oak Ridge, TN (1983). 2. B. L. Cohen and I-S. Lee, Hlth Phys. 36, 707 (1979). 3. A. P. Watson, T. E. Birchfield and C. S. Fore, “Risk Assessment of Coal Production: An Information Systems User’s Manual”, Oak Ridge National Laboratory Report ORNL/TM-842 I, Oak Ridge, TN (October 1982). 4. A. P. Watson, “Factors Affecting Lost-Time and Fatal Injury Incidence in U.S. Coal Mines”, Oak Ridge National Laboratory Report ORNL/PPA-83/7, Oak Ridge, TN (June 1983). 5. F. R. O’Donnell and H. C. Hoy, “Occupational and Safety Data and Casualty Rates for the Coal Fuel Cycle”, Oak Ridge National Laboratory Report ORNL/TM-8442, Oak Ridge, TN (in review). 6. E. L. Hillsman, P. E. Johnson and B. E. Peterson, “Predicting Routes of Radioactive Wastes Moved on the U.S. Railroad System”, PATRAM 80. Proceedings, 6th International Symposium on Packaging and Transportation of Radioactive Materials (Edited by H. W. Hubner), Vol. I, pp. 359-366. International Congress Center, West Berlin (1980). 7. D. S. Joy, P. E. Johnson, D. B. Clarke and S. C. McGuire, “Predicting Transportation Routes for Radioactive Wastes”, Presented at the ANS Topical Meeting, Waste Management ‘81: Waste Isolation in the U.S. and Elsewhere, Technical Program and Communication, Vol. 1, pp. 415-425, Tucson, Arizona (I98 1). 8. U.S. Department of Transportation, “Transportation Safety Information Report”, 4th Quarter Highlights and Summary, USDOT, Transportation Information Division (1976). 9. U.S. Department of Transportation, “Transportation Safety Information Report”, October, November, and December, NTISUB/C/224-004, USDOT (I 977). IO. U.S. Department of Transportation, “Transportation Safety Information Report”, Annual Summary (March), NTISUB/D/224-004, USDOT (1979). 1I. U.S. Department of Transportation, “Transportation Safety Information Report”, October, November, and December, NTISUB/D/224-004, USDOT (1978). 12. U.S. Department of Transportation, “Transportation Safety Information Report”, October, November, and December, NTISUB/D/224-004, USDOT (1979). 13. U.S. Department of Transportation, “National Transportation Statistics”, DOT-TSC-RSPA-79- 19, USDOT (1979).