MARQUETTE, MICH. — DRIVING south on state road M35, away from Marquette County Airport, past miles of deep green forests, one encounters a startled doe standing alone on a pair of rusted railroad tracks.Going through a small, empty-looking village you approach mountains of charcoal-colored rock. This is waste material that surrounds the Empire Mine, an open-pit source of iron ore that has been in operation here since 1963. Large, electric shovels dig at the bottom of the pit, and 170-ton-capacity trucks look like ants making their way up the switch-back roads. The pit is 600 feet deep, three-fourths of a mile wide, and 1 and 1/2 miles long. The Empire Mine is one of two open-pit iron mines still operating in Marquette County. The two mines employ about 2,000 workers. They still constitute the largest employer in Marquette County, says Don G. Ryan, director of public affairs for Cleveland Cliffs, the company that owns part of the mines and manages them. "Up until the 1950s," says Mr. Ryan, a very high-grade ore was mined here. "Many people thought the rest of this was too low-grade, but the pelletizing process was developed in 1956. "This is what we're doing here now - mining the ore with the rock. It's about 50 percent rock and 50 percent ore that we remove from the pit. We separate that, then get the ore back to a concentrate for shipping," he says. MUCH has changed since the days of underground mining, but one thing still looks pretty much the same. Just before entering the concentrating plant, on the right, is "the dry." This is a large locker room that bears the same name it has had since the early days of mining on the Upper Peninsula, says Ryan. Large, square wire baskets hanging from the ceiling are covered with the dark mining dust that is everywhere. They look like old bicycle baskets. Here the miners hang their clothes before and after work. They also hang their lunch buckets, thermos bottles, flashlights, and other items from these baskets. The mine is divided into three sections - the pit where the ore is mined, the concentrating area where the ore is ground into fine powder and separated from silica residue, and the pelletizing plant where the fine powder is rolled into pellets. These pellets are put in a kiln and heated to 2,400 degrees Fahrenheit. After that, they're loaded on train cars to be transported to Marquette or Escanaba for shipping on the Great Lakes to many steel mills in the United States and Canada. Ryan says, "We still have a direct impact of about $200 million per year - money which comes into this area for the rocks we mine; money that is spent here." He adds that there still is about 40 years of ore to be mined from this pit.