Near the end of the 17th century, Louis XIV pulled down a colossal fortress at Chatel sur Moselle. And then he buried what was left under rocks and dirt. For two summers I was one of a group of 30 French and American students who tried to dig it out.

Each summer hundreds of students from America and western Europe gather among the stone ruins of French chateaux and fortresses to reconstruct and preserve an impressive part of France's rich heritage. The program is run by REMPART, a French governmental program with help from US/ICOMOS, a non-profit preservation group.

Volunteers come from broad backgrounds with an equally broad range of compulsions. Although most American participants are students with interest in preservation, it's as common to find electricians and train engineers among the French as students of architecture and art history.

In the mountainous Vosges region to the east of Paris, Chatel enjoys a view of the Moselle River. In Roman times Chatel lay at the crossroads of two Roman highways. The fortress itself was begun in the 11th century and flourished from the 15th century until near the end of the 17th when Louis xiv pulled down its towers in his effort to eliminate provincial opposition to the centralization of his government in Paris.

King Louis wasn't thinking much about preservation when he buried the chateau but the fill helped to preserve the solid structure and for nine seasons, volunteers have dug it out with considerable success. The fortress' mighty walls rise some 50 feet above the village and conceal an extensive network of halls and passageways.

At the base of the fortification, a side entrance leads into a cavernous stairwell. The stairs are unusually steep to make it hard for invaders. Loopholes in three walls enclose the stairwell to make it virtually impregnable. Remnants of the stronghold's interior fortifications are still to be seen in the base of a massive tower. The cellar, now fully restored, was probably used for the storage of weapons.

Work at Chatel sur Moselle was not easy. We had to work with picks and shovel heavy loads to uncover the site. Then we had to find the right stones before we could rebuild stairways and walls.

Most of us had never built stone walls before. After spending several days building one wall, working hard to keep it straight, I had to tear it down because our director had forgotten to lay an electrical cable behind it. I had been so careful building the damned thing that I had more trouble tearing it down than I had building it. In the end, we needed a hydraulic pick to do the job.

It was never hard to find volunteers for cooking duty since our chefs always left work early to cook lunch and dinner. Tension was at its greatest when anyone got out of the work. The jealous looks of my friends sometimes made it difficult for me to photograph them.

The dullest and most unpleasant task was to chisel and brush the walls to remove loose stone and concrete before replacing the mortar. Repointing, as it's called, was necessary to protect the walls from weather. The old mortar crumbled to powder as we removed the soil and rocks. Stone dust always got into our eyes. The constant hammering of chisels or the drone of our hydraulic pick was irritating.

Other work was more exciting and, in any case, no one got stuck with a dull job for too long. The chateau contains many wells, necessary if the occupants had had to resist a long siege. After one of us almost fell through a well whose fill had stuck half way, we dug out the wells with ropes around our waists to prevent us from falling.

The most pleasant aspect of the work was speculating about the original use of a wall or passageway and the best possible way to display the site. Sometimes reconstruction had to be innovative to accommodate adaptive uses for the structures, but where possible we tried to remain faithful to the original design. The question to what extent should the present meddle with the past was always with us.

Some days are longer than others but a chantier rarely works more than 30 hours a week.

Since the afternoon heat was intense, we took a daily siesta and worked in the mornings and late afternoons.

Living accommodations are rustic and vary from chantier to chantier .

At Chatel, we slept in sleeping bags and the dormitories were coed. We were housed in five dusty but spacious rooms of an early 18th-century monastery. The monastery stands in one corner of the chateau. The monks used the destroyed fortress' walls and ramparts for the foundation of their own building.

Everybody cooked and cleaned -- and argued about everything from mixing concrete to making mayonnaise. The favorite prank was to turn the mayonnaise in the wrong direction to make it fall apart on our friends.

The brotherhood of our French-American team was in full color at a Fourth of July champagne party and more champagne and a masquerade ball to celebrate Bastille Day. We danced in a room of the chateau. about many regions of France. In addition to chateaux, other projects include churches, chapels, abbeys, fortresses, farmhouses, and washhouses. In 1978, I worked for two weeks to help repair the roof of an early 19th-century washhouse in southern Burgundy.

More than 100 chantiers are sponsored by REMPART each summer in chateaux and ruins in the heart of France. REMPART (acronym for the Union des Associations Animatrices de Chantiers de Sauvegarde pour la Rehabilitation et l'Entretien des Monuments et du Patrimoine Artistique ) is a confederation of 90 French community groups and volunteers who work on the preservation and conservation of monuments and properties.

Now in its fifth year, American participation in the French programs is directed by Terry B. Morton, chairman of the U.S. National Committee for the International Council of Monuments and Sites (US/ICOMOS). ICOMOS was established in 1965 to promote the study and and conservation of historic monuments, buildings, and districts.

The deadline for the 120 places in the 1980 US/ICOMOS Summer Workshops in France has been extended until Feb. 15. Applicants must be 17 or older, interested in historic preservation, and able to speak French. They must pay their own way to France and home again, but basic food and lodging are provided during the two week workshops. For information and applications, write to the US/ICOMOS Secretariat, 1785 Massachusetts Ave., N.W., Washington, D.C. 20036. (202) 673-4080.