An Energy Department study of coal transportation patterns confirms a long- term shift toward greater shipments of Western coal accompanied by a sharp drop in those from Appalachia.

Shipments from Wyoming, Montana, Colorado and adjacent states increased

from 6 percent in 1970 to 36 percent of U.S. production by 1990. Appalachian coal originations from eastern Kentucky, West Virginia, Virginia and adjacent states fell, to 42 percent from 65 percent in the same period. Using shorter

comparison dates of 1980 to 1990, Appalachian coal lost 6 percent of market share, while Western coal gained 7 percent.The department's Energy Information Administration was required to develop the study under the terms of the Energy Policy Act of 1992.

Coal consumption also shifted sharply, with increased shipments to the South and West, and lower shipment volumes to the Midwest and Northeast.

Rail and truck market shares remained relatively stable, but water shipments of coal declined, to 17 percent from 29 percent between 1970 and 1990, and shipments by conveyor, tramway or pipeline increased, to 13 percent

from 4 percent in the same period.

The study finds a lack of current data on rail rates.

It cites a 1991 Energy Information Administration report with rail coal- shipment rate information from 1979 through 1987. It showed little change in rail rates per ton mile.

The latest review by that agency had no more recent information on coal rates, citing the lack of a current database. Separate databases maintained by the agency, the Federal Energy Regulatory Commission and the Interstate Commerce Commission have some, but not all information needed to measure shipment routing, tonnage, mileage, transport mode, and rates.

More than 90 percent of rail coal shipments move under contracts whose rates are confidential.

The Energy Information Administration recommends expanding an energy

commission database, covering 58 percent of coal, to include all coal shipments by agreeing to protect future confidentiality of data supplied by utilities that don't participate now.

As part of the study, the department found that no federal agency is studying implications of the Clean Air Act of 1990 on the railroad industry.

That legislation was designed to reduce pollution by requiring use of lower-sulfur coal, shifting production to more efficient plants, installing pollution control devices or allowing to buy or sell credits for various plants' emissions to achieve overall compliance.