Underground coal mines operated by Utah Power & Light Co. are among the safest in the United States.

A study by the Occupational Safety and Health Law Center involving the 20 largest underground coal producers, ranks UP&L fifth."We are obviously pleased to be among the safest mines in the nation," said UP&L spokesman John Serfustini. "But rankings are just a byproduct of continuing efforts to improve safety."

UP&L has 250 miners at its Wilberg-Cottonwood mines and 261 at its Deer Creek operations. The mines produce more than 6 million tons of coal annually for use at the company's power generating plants.

Good ratings "contribute to higher morale and productivity," Serfustini said. "I think we've proven that productivity and safety do march hand in hand."

The study developed rankings based on the average number of injuries and deaths for every 200,000 employee hours, the number of hours 100 full-time employees work in a year. The rates are the average number of miners hurt or killed for every 100 full-time employees.

UP&L's 3.3 rating was lower than the 4.2 national average reported in the study.

Here is a complete list of the safety rankings, from best to worst, of the 20 largest U.S. underground coal mining companies.

1. Consolidation Coal Co., Pittsburgh, 2.1

2. American Electric Power, Columbus, Ohio, 2.5

3. Sun Co. Inc., Radnor, Pa., 2.8

4. Jim Walter Resources Inc., Birmingham, Ala., 3.1

5. Utah Power & Light Co., Salt Lake City, 3.3

6. Cyprus Minerals, Englewood, Calif., 3.8

7. Coastal States Energy, Salt Lake City, 3.9

8. Island Creek Coal Co., Lexington, Ky., 4.1

9. B.P. America (Old Ben Coal Co.), Cleveland, 4.2

10. Rochester and Pittsburgh Coal Co., Indiana, Pa., 4.4

11. A.T. Massey, Richmond, Va., 4.4

12. Bethlehem Steel Corp., Bethlehem, Pa., 4.6

13. U.S. Steel Mining Co., Pittsburgh, 4.9

14. Peabody Coal Co., Henderson, Ky., 5.5

15. Mapco Inc., Tulsa, Okla., 5.8

16. Henry Paul Kizer, et. al., Beckley, W.Va., 5.8

17. Shell Mining Co., Houston, 6.0

18. Pyro Mining Co., Sturgis, Ky., 6.4

19. Pittston Co., Greenwich, Conn., 7.0

20. Monterey Coal Co., Carlinville, Ill., 7.8