“This mine was designed to do 3 ½ million tons plus per year,” Boone says. “We could do that without making any significant changes, but the market hasn’t required us to do that yet.”

The crew

It takes a special person to work underground, especially in wintertime when the days are short. Employees working the regular 10-hour shift go down into the mine before the sun comes up and return to the surface after it has set. “They never see the light of day in the winter,” Boone says. “You can’t take the first man or woman off the street and turn them into a miner. They have to want to do that.”

The “race track” and loadout bins around the stockpiles allow trucks to come in, pull right up, and load themselves.

When aggregate demand is low in the winter, the quarry runs mostly the chemical lime level and employs about 39 people; about 25 of those employees work underground. In the summertime, when demand for aggregate increases, the quarry employs about 50 people and runs both the chemical and aggregate levels of the mine at the same time.

Probably one of the most unusual things about Sterling Materials’ employees is that all the underground truck drivers and most of the underground crusher operators are women. “They keep their equipment clean and in good working order,” Boone says. “They seem to have more pride in what they’re doing than the typical male we’ve had previously.”

“Ten years ago, you’d have never thought it would happen,” Van says. “Back then, if a woman went underground, that mine was jinxed. Women have come a long way.”

Van says that the miners are like family. “They know each other well,” he says. “When the weather’s bad, one person will go around and pick up some of the employees that live further out and bring them in.”

The processing plant

The only part of the operation above ground is the aggregate processing plant. This looks like any other processing plant, but the screens are housed inside buildings to protect them from the elements. After the product is processed through the screens, conveyors run the finished, sorted material out to the various stockpiles to await loadout.

“When we built this, we came out to the hilltop, cut off the top, and set up this processing plant,” Van says. “We’ve got 8s, 57s, DGA, crushed stone base, and 2s in different stockpiles around the rim of the hill.” Tunnels were built underneath the stockpiles with conveyors running product out to the “race track” that was built around the hill. The race track and loadout bins allow trucks to come in, pull right up, and load themselves.

“I’ve got these loadouts set for 10 tons a minute, so if the truck driver wants 25 tons, he runs 2 ½ minutes,” Van says. “The trucks just pull up under whichever type rock they want and load up.”

Underground challenges

Underground mining is highly regulated, like any quarry. “We get four mandatory MSHA (Mine Safety and Health Administration) visits per year,” Boone says, “but we usually get even more [visits] because we’re in proximity to the Lexington office.”

Air quality is the major issue. “Air regulations are getting more stringent every year, but we meet whatever the next requirements are,” Boone says. “We burn biofuel as much as possible — up to 90 percent — which helps, and we have very good ventilation throughout the mine, especially in work areas.”