Chevron U.S.A. isn't the oldest operator along refinery row north of Salt Lake City, but it's probably the proudest.

Pintsize in comparison to the oil giant's other refineries, the Salt Lake operation holds its own among Chevron plants by earning a healthy profit and serving a strategic region in the Mountain West.Pride in the operation was exhibited recently as Chevron celebrated the 40th birthday of its Salt Lake Refinery. Local Chevron employees proudly guided family, friends and local dignitaries through the refinery's maze of crackers, cokers, boilers and cooling towers.

"We think this is a pretty nice place," said a burly plant mechanic passing out commemorative hats inside the refinery's main office building before the event.

In the southwest corner of the building is the office of refinery manager Jerry Moffitt. The Salt Lake native and 25-year veteran with Chevron has worked at the oil company's largest plants and says the Utah refinery, though small by comparison, is unique.

"We are the only plant in our system with a captive crude supply," he said.

That captive resource in Colorado and Utah is why the company constructed the Salt Lake refinery, which now employs more than 190 workers processing about 45,000 barrels of oil per day, and is the main reason for the plant's success.

It was in 1933 that Chevron discovered oil in Rangley, Colo., and the idea of transporting it to a Salt Lake refinery came to mind as a way to serve a growing Utah-Idaho market with petroleum products. The idea became reality in 1948, shortly after Chevron completed a 182-mile pipeline from Rangley over the 9,560 foot Wolf Creek Pass, running along the northern foothills of Salt Lake Valley and passing 800 yards from the state Capitol before reaching the new Salt Lake refinery.

The pipeline, which can carry up to 53,000 barrels of crude, traverses the Uintah Basin where it teams up with another line gathering crude from wells in the Altamont-Bluebell fields, delivering the raw material to several refineries along the Wasatch Front.

One branch of the pipeline directs crude into Chevron's storage tanks before the raw material goes through a complex refining process that produces about 35,000 barrels of gasolines, jet fuel and diesel fuel.

Most of the gasoline is sold to the more than 130 Chevron gas stations throughout the state. The largest commercial jet fuel customer is the Salt Lake International Airport, fed through a pipeline directly from the refinery, and Hill Air Force Base and the Utah National Guard are top users of military aviation fuel.

Other products coming from the Salt Lake refinery include propane, butane, sulfur, coke and gas oil.

About 10,000 tons of coke is produced annually from crude residue and is purchased by aluminum manufacturers. The refinery ships the gas oil - containing a waxy material unique to eastern Utah oil - to a Chevron plant in California, where it is refined into commercially usable wax such as that used on milk cartons.

In addition to serving most of Utah, the refinery also ships its products by pipeline to Spokane, Wash., and supplies petroleum products to major markets along the 705-mile route through Idaho and eastern Oregon and Washington. Moffitt said about two-thirds of the refinery's products go to out-of-state markets.

The refinery hasn't undergone much change since the early 1970s, when it installed a coke producing facility and a desulfurization plant. In this decade, Moffitt said, the plant has upgraded facilities to comply with air, water and hazardous waste environmental laws.

But the lack of significant changes doesn't mean the refinery has been neglected. A constant maintenance program keeps the plant operating continuously, 7-days a week, 24-hours a day, since it treated its first drop of crude 40 years ago.

Officials said the only time the refinery completely shut down was three years ago, when almost the entire state suffered an electrical blackout. Although the black smoke gas flares provided an alarming sight, no equipment or workers were hurt by the short shutdown.

"It's like an amusement park where a whole bunch of rides make up the park," Moffitt said of the refinery. "Well, here a whole bunch of plants make up the refinery and we keep them all running by doing piecemeal maintenance."

About the only amusing ride you see anyone taking at Chevron is an occasional technician peddling a fat-tired bicycle to the lab to test a fuel blend sample. Otherwise, safety signs posted throughout the facility indicate running a refinery with oil and fuel flowing in about 2,000 miles of pipe weaving throughout the plant is serious business.

The drop in world oil prices in recent years did result in some early retirements at the Salt Lake refinery. But Chevron's Salt Lake refinery still operates at more than 90 percent capacity and at a profit, Moffitt said.

On a per-barrel basis, the Salt Lake refinery is one of the most profitable in the Chevron system, local spokesman Gary Fisher said, noting plant profit figures are confidential.

The key to Chevron's success in Salt Lake is the refinery's economical crude resource from western Colorado, Wyoming and eastern Utah. The low cost resource is readily available, inexpensive to transport by pipeline or truck, and Chevron's refinery, specially designed to handle eastern Utah's waxy crude oil, has low fixed operational costs, Fisher said.

Crude oil in the Rocky Mountain region fetched about $15 a barrel last month, and the industry standard for refining costs is about $3 to $5 a barrel.

Fisher explained that advanced technology in oil recovery from wells reduces the risk of the Salt Lake refinery's resource drying up.

"It's got a limit at some point, but nobody knows when that will be," he said.

In late 1985, Chevron sold many of its Utah oil properties and demand for eastern Utah oil has slackened, so that Chevron Pipeline's second line to Salt Lake is not in operation.

"But there still is a lot of oil out there," Fisher said.