Coal - Energy Policy Analysis: A Conceptual Framework - page 27

Barge
Transportation of coal by water has long taken advantage of the nation's 29,000 miles of navigable
waterways, including the inland Mississippi system, the Gulf and Atlantic Intracoastal system,
and the Great Lakes. Coal traffic accounts for over 20 percent of all waterborne shipments. When
geography permits, transportation by water is more efficient than rail transport at about one-third
the cost of comparable rail transport.
Most coal in river traffic is shipped in open hopper barges with a capacity of 1,000 to 1,500
tons. The barges are usually lashed together to form a tow of as many as thirty-six barges. Diesel-
propelled towboats of up to 10,000 horsepower are used to push the load. For oceangoing and Great
Lakes operation, self-propelled bulk cargo carriers averaging 20,000-ton capacity are used instead
of barge and towboat configurations (Christman et al. 1980, 188; Witten and Desai 1978).
In addition to the chronic problem of fugitive dust, principal air pollution emissions from river
vessels include sulfur dioxide, carbon monoxide, hydrocarbons, and nitrogen oxides. Accidental
discharge of coal loads to water is also of concern, and coal barge traffic must share responsibil-
ity for shore erosion as a result of passing wakes. However, the most serious problem resulting
from coal barge traffic is the increase in congestion of inland waterway systems, especially on
the Mississippi River, where locks and dams have been operating at or above capacity for many
years. Barge transportation is in general more energy-efficient than rail transport (Christman et
al. 1980, 191).
Trucks
In surface mining operations, coal is loaded onto trucks at the coal face and carried to storage piles
or conveyor belts for subsequent rail or barge transport. Small mines (surface or underground)
without loading facilities may also use trucks to carry coal to central receiving areas where the
output of several mines is combined, but the economic range of coal trucks is approximately 150
miles. The high coal volume required by large industrial plants limits truck use to mine-mouth
power plant operation. Highway limitations prohibit trucks from exceeding forty tons gross weight.
The largest coal trucks in highway use weigh approximately ten tons and have a thirty-ton carrying
capacity. Truck transportation of coal can result in severe road degradation. Damage from one
55,000-pound (27.5 ton) truck has been shown to be equivalent to the wear produced by 2,500
automobiles (Christman et al. 1980, 193). Principal air emissions from these large trucks include
carbon monoxide, hydrocarbons, nitrogen oxides, aldehydes, sulfur oxides, and particulate matter.
Noise, congestion, and safety are also problems with truck transport.
It is often most economical to take advantage of more than one mode to transport coal from mine
to end user. For example, the Burlington Northern Railroad operates a transshipment terminal in
Havanna, Illinois, where 5 million tons of coal from Decker, Montana, are first carried by rail and
then transferred to barges on the Illinois River for subsequent delivery to three Commonwealth
Edison utility plants in the Chicago area (Christman et al. 1980, 195).
COAL STORAGE
Mine operators generally minimize the amount of coal stockpiled at mine sites because unshipped
coal does not recover the costs of extracting it from the ground and because stockpiles are prone
to spontaneous combustion. Temporary stockpiles at preparation plants and shipping docks are
generally minimized as coal is transported from the mine to purchasers as rapidly as possible. At