For a joint venture operating in Bartlett, IL, a major challenge of turning limestone reserves into profits is simply gaining access to them.
As part of an agreement with aggregate suppliers Vulcan Materials and Bluff City Materials, Iron Horse Grading and Excavating is performing a mass excavation on a 186-acre (75.3 ha) site, to provide access to limestone known to be in the area.
According to Dave Hansen, owner of Hampshire, IL-based Iron Horse, the project involves digging a portal 755 by 550 ft. (230 by 167 m) and 147 ft. (45 m) deep, supplying entry to the underground reserves, which are expected to yield grade A limestone for at least 50 to 60 years.
Iron Horse has relied heavily on two Hitachi EX 1200 excavators from Howell Tractor & Equipment, a 60-year-old distributor with locations in Elk Grove Village and Peru, IL, and in Gary, IN.
“We’ve had one for two and a half years, and I think there has only been about four hours downtime on it, other than normal servicing,” said Hansen of the Hitachi. “We bought the second 1200 in August.”
Equipped with 14-cu.-yd. (10.7 cu m) Badger buckets manufactured in Milwaukee, the 1200 excavators can move an estimated 35,000 cu. yds. (26,789 cu m) or more daily, according to the manufacturer.
“We’re very happy with the production on both machines. The dependability has been excellent,” Hansen said.
The origins of the mass excavation project can be traced back a couple of years.
Bluff City Materials is a 15-year-old sand and gravel operation with seven mining locations in Elgin, Bartlett, South Elgin and South Beloit. After buying Chicago Sand & Gravel and all its reserves in November 2001, Bluff City Materials performed exploratory drilling, and discovered a substantial amount of high-quality limestone over a large area. The company decided to work underground due to the proximity of Bluff Spring Fen nature preserve.
As a result, Bluff City began pursuing permits needed to access and eventually harvest the material for processing.
According to Matt Vondra, construction manager of Bluff City Materials Inc., his company decided to work with Iron Horse on excavation, “not only because of price, but mainly because he’s an excellent contractor — he can move an incredible amount of material in a short amount of time — and because of Vulcan Materials’ previous experience with Iron Horse.”
Planning took about two years, and permitting, about nine months, said Vondra.
The original process began in Elgin, IL, but Bluff City officials found the town was not as receptive to underground mining, blasting and other industrial operations as they would have liked. Vondra said they turned to the town of Bartlett, IL, instead.
There, Bluff City installed the mine and obtained zoning for both an asphalt batch plant and liquid asphalt storage facility, all on a 186-acre job site.
Vondra described the parameters of the entry to the limestone reserves.
“We have a 10-acre hole, 175 ft. (53 m) deep at the deepest point before we enter the portal. The decline will be about 1,500 ft (457 m) long, and we’ll go down to a depth of 350 ft. (106 m). From there, we’ll meet the mine horizon, set up the crusher room and begin the mining operation.
Heavy-duty equipment has proved crucial throughout the process.
“We’ve had Hitachis now for over 10 years,” said Hansen. “We started with the smaller ones, and now that we’re into the bigger mass excavators, the EX1200s have performed extremely well for us.”
In addition to the EX1200s, Hitachi has figured prominently into the rest of the equipment fleet, as well.
Of the 16 trucks onsite for the mass excavation, five are 40-ton (36 t) AH 400 Hitachi articulated trucks.
“This was a new truck. We were probably the first one in the States to have one. These [AH 400] trucks have also performed very well,” Hansen said.
Vondra said each truck can be fully loaded in 20 to 32 seconds using just two scoops of material, because of the 14-cu.-yd. buckets on the excavators.
Other equipment at work on the project includes two Cat D10s and a D9 tractor with Cat 16 blades, and Cat 815 and 825 compactors.
Since starting the job in August, crews have worked 11 hours a day, five days a week, plus eight hours on Saturdays. They expect to finish by the end of October.