Hundreds of military vehicles lumbered through the Dugway Proving Ground gate Thursday as 12,400 artillery troops left Firex '88 in the dust and returned to their civilian lives.

The Army National Guard and Army Reserve soldiers under I Corps command came to Utah's West Desert to participate in the largest live-fire training exercise of its kind ever conducted by U.S. military forces. An additional 3,000 or so National Guard members and reservists provided support for the artillery soldiers, and they have been packing their bags for home also, though remnants of the exercise will be visible at Dugway, Tooele Army Depot and Camp Williams through the weekend.

National Guard officials must now wrap up the mock war on paper to gauge success of the exercise.

Brig. Gen. James M. Miller, I Corps artillery commander and Firex director, said the exercise was over budget, but he hoped Pentagon officials would see the value of this kind of large-scale training and approve another one, possibly three years from now.

Many high-ranking military officials visited Dugway while the exercise was in progress. Most of them were on hand Wednesday during the 2 p.m. "Time on Target" mass firing when all 180 howitzer cannons were firing at target areas during a two-hour period.

All told, 20,000 artillery shells pummeled the desert floor during the exercise. Rockets and bombs from helicopter gunships and jets also pelted the target areas.

When the firing stopped and orders were given to pack the guns and head home, camouflage netting that had covered guns, trucks and trailers began to drop almost instantly, said Lt. Col. Reece Stein.

Rather than try to thoroughly clean tents and equipment in Dugway's dust bowl, gear was stowed and will be detailed back at home base. Most of the vehicles in highway convoys were coated with fine, light-colored dust.

Equipment that came from regional guard units streamed down I-80 in caravans. Cannons and other heavy equipment brought from California and Midwestern states was taken to Tooele Army Depot where it was loaded on rail cars to be shipped out.

More than 2,000 injuries were treated during the exercise, according to casualty records as of Thursday afternoon. Many of the injuries were the undesirable result of the West Desert's hot temperatures. Only 103 of those injured were admitted in the evacuation hospital that set up camp at Dugway.

No fatalities had been reported as of Thursday afternoon, which was especially comforting because military mortality charts predicted at least seven soldiers could die while participating in the exercise, Miller said. (see related story on B1.)

The only casualty was the 10,000 acres of Bureau of Land Management range land adjacent to Dugway that burned Wednesday and Thursday after dry grass was ignited, probably by an artillery shell.