During the height of the controversy surrounding the transfer of U.S technology for building the trans-Siberian pipeline, the Soviet Union approached an American corporation through an intermediary to seek its participation in a massive coal slurry pipeline project in the Soviet Union, according to former congressman Dan Kuykendall (R-Tenn.).

Officials of Methacoal Corp., a small firm based in Dallas, decided after discussions with Department of Commerce officials, not to participate in the project because of the controversy surrounding the trans-Siberian natural gas pipeline to Western Europe. "It was our patriotic duty not to pass on the technology," said Kuykendall, a consultant who also is a shareholder of Methacoal's parent corporation, the Keller Corp. He said the company was not pressured by the Commerce Department.

The possibility of U.S. participation in a huge project to send liquified coal from Siberia to European Russia came to light at a recent meeting in Moscow between Soviet officials, industrialist Armand Hammer, and officials of Bechtel Corp.

According to Kuykendall, currently a Washington consultant, Methacoal was approached indirectly earlier this year by the Soviets through an Italian intermediary, Finsider, The Italian national steel company that hopes to provide pipe for the project.

Leonard Keller, President of Methacoal received a telephone call March 17 from Vittorio Cavalerri, managing director of Finsider, to discuss Methacoal participation in the development of the pipeline.

A subsequent meeting took place in New York between Keller and Cavalerri in May. Keller said Cavalerri told him he was acting as an intermediary for Soviet officials.

Methacoal claims to be the sole patent owner in the United States of the process of mixing methyl alcohol and coal to produce a liquified form of coal.

Ironically, there are no coal slurry projects employing that technology in this country, according to Department of Energy officials.