NATHAN AVERY, PRESIDENT of Galveston-Houston Co., Houston, is about to be named to a top post at the Commerce Department.

The Texas energy executive will have the job of ensuring that U.S. companies, in all industries, have fair access to business opportunities in the single-market European economy after 1992.Mr. Avery is said to have been recruited directly by Secretary of Commerce Robert Mosbacher. He'll serve in Brussels, Belgium, beginning in October, as Commerce's minister-counselor to the European Community.

Commerce isn't commenting on the appointment, but Mr. Avery has notified his company's board of directors that he will accept the position after standard federal approval procedures have been completed.

Washington sources commented that Mr. Avery is expected to be an aggressive defender of U.S. trading rights, whose primary task will be to oppose regulations and practices in the new arena that discriminate against U.S. companies.

Galveston-Houston manufactures valve actuators and custom steel casings for energy developers as well as excavation buckets and parts for the mining and construction industries.

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RESPONDING TO A QUESTION about Moscow's curtailment of natural gas, oil and coal to Lithuania, Henson Moore, the deputy energy secretary, said he would not raise the issue of the insecurity of Soviet energy supplies while in Europe this week to promote U.S. energy goods and services.

Mr. Moore met with a small group of reporters before leaving Washington for stops in Italy and Belgium. Italy, among other Western European countries, is dependent on Soviet natural gas deliveries via pipeline. It's also a major market for U.S. coal - one that U.S. producers would like to see expanded.

Mr. Moore commented that he would not be successful in dissuading European energy consumers from relying on the Soviet Union, with whom they have a general interest in expanding trade. He added that the cutoff of energy to Lithuania is viewed "as an aberration."

The second-ranking Energy Department official said at the briefing he expects to name in about 30 days a deputy assistant secretary to direct the DOE's newly created Office of Export Assistance.

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JAPANESE INVESTORS ARE INTERESTED in funding 50 percent of the Port of Los Angeles' $108 million coal terminal expansion project.

Are other Japanese investments in the U.S. coal industry looming on the horizon?

A source knowledgeable about the Los Angeles project says yes. He predicted an announcement soon about Japanese involvement in a joint venture with a U.S. company to construct a Western coal mine. No other details were provided.

Another source said a major Western Canadian coal producer is interested in opening a Western U.S. mine.

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HOUSE SOURCES SAID IT WILL BE the third week of May at the earliest before the full House can begin debating the Clean Air Act and its acid rain control provisions.

That allows time for the Energy and Commerce Committee to finish writing its report on the measure while key legislators try work out still unresolved issues behind the scenes.

Two other committees will have a short period to review portions of the legislation falling within their jurisdictions, but that's not expected to stall action on the bill.