Former Attorney General Edward H. Levi has advised the Interior Department that it acted improperly when it reprimanded an administration law judge for trying to fine a coal company.

Levi's opinion, issued shortly before he left office, concerned the case of Joseph B. Kennedy, an Interior administrative law judge who hears cases primarily involving mine safety violations.

Last Feb. 2, Kennedy fined Harlan No. 4 Coal Co. of Knoxville, $2,682 for 25 violations. he subsequently was given an official reprimand by former Interior Under Secretary Kent Frizzell, who charged that Kennedy's action was contrary to an order of a U.S. District Court in Kentucky.

Kennedy protested the reprimand; and the Interior Department referred the matter to Levi for his opinion. He said his examination of the law indicated that, while administrative law judges are subject to discipline by the Interior Department, they also have independence of action in conducting their hearings.

In the Harlan case, Levi said, Kennedy was in a position where he had to make a judgement "according to his own understanding and conscience." Accordingly, he added, "an agency reprimand with respect to that decision was improper."

If the Interior Department considered Kennedy's action improper, Levi concluded, its proper course was not a reprimand but to overturn his decision through its internal review processes and, if it it felt disciplinary action was required, to file charges against him with the Civil Service Commission.