Just outside of Rochester, N.Y., one of the oldest road salt mines in the world was flooded in the mid 1990s, and the owner eventually decided to close down the operation. Dedicated to returning mining to the area, a local businessman, and third-generation miner, formed American Rock Salt, LLC (ARSCo).
Efforts to rebuild the mine began with ARSCo turning to Frontier Kemper/Flatiron Joint Venture, headquartered in Evansville, Ind., to be the general contractor for the project. The civil contractor was chosen because of its experience in sinking shafts and building tunnels. And it was O’Connell Electric Co., Victor, N.Y., that was chosen to be the electrical contractor to install the electrical, controls and automation, and communications systems for the new mine.
Although a previous relationship existed between O’Connell Electric and one of ARSCo’s key executives, the company still had to compete for the more than $7 million electrical project. “We were awarded the contract because of the competitive nature of the bid and the company’s standing as one of the largest and most reputable contractors in the Northeast,” said Victor Salerno, executive vice president.
Because the original plans for refurbishing the mine were made in 1995, O’Connell began work on the project by collaborating closely with ARSCo engineers to update the designs in a way that would take advantage of the most current advances and upgrades in technology. “Our involvement with the project from the design through the construction phases allowed us to help the customer integrate the entire operation, including the fiber optic communcation backbone, the power distribution systems and the automated process controls,” said Walter Parkes, O’Connell president.
An enormous task
Work on the approximately $65 million mine project began in the summer of 1999, and was completed in September 2001. O’Connell Electric employed an average of 12 electricians and two data technicians, with a peak staffing level of 30 electricians. “The very complex project required more than 50,000 labor hours and included all phases of electrical construction for the buildings, tunnels, substations and railroads,” stated Tim Ehmann, O’Connell project manager.
In 1999, while the earthmovers began grading the mile-long site that would accommodate all of the outbuildings, O’Connell Electric began construction of the 5-mile, 115kV transmission line across the Genessee Valley that would allow the local utility company to feed temporary power to the site. From that same transmission line, engineers used 34kV to sink the two 1,200-foot shafts (which were 1,000 feet apart) that would eventually extract the salt from the earth. In addition, O’Connell Electric completed construction on the 18MVA permanent power distribution substation and hooked it into the transmission line on the same day that the two shafts were joined at the base. “This was a huge milestone for the project,” said Ehmann. “Maintaining the temporary 34kV power distribution for the shaft construction was a year-and-a-half-long challenge in itself.”
The main workhorses of the plant are the hoists located in the shafts, one of which is used for extracting the salt and the other to transport men and equipment. The two hoists also serve as the main distribution hubs for the 13.8kV power distribution system. “The power distribution system enters the mine via the shafts and feeds the underground operation through a dual feed switchboard,” explained Ehmann.
Frontier Kemper also excavated and constructed a 5,000-ton holding pen, processing crusher and loading facility, designed to process and transport more than 1,000 tons per hour of road-grade de-icing salt to the surface. It was, however, O’Connell Electric that was responsible for wiring the power, motor control centers and programmable logic controllers (PLCs) for the conveyor systems that connect the three underground excavation caverns. “It took 2 miles of mine power cable, 8 miles of jacketed armored cable, and countless fiberglass cable trays, messenger supported innerducts, fiber optic cables and specialized mine vehicles to complete the job,” recalled Ehmann.
Above ground, the finished product is conveyed to either a 400,000-ton storage pile that is environmentally engineered to eliminate groundwater pollution, a three-bay truck loading facility or a train-car loading system. “However, that computerized, automated conveyer is 85 feet high,” observed Salerno.
O’Connell Electric installed the wireless control PLCs and the 1,100-foot power rails that feed and control the conveyor cars and dust containment chutes that create the mammoth storage pile. “Each of the six major elevator conveyor systems and dust collectors are powered, controlled and monitored by their own motor control centers, PLCs and fiber optic panels,” explained Ehmann. Integrated into the control system are complete conveyor safety and belt tracking systems, walkway illumination, fire alarm monitoring, mine site communication and even some site security camera operations, all of which are controlled or monitored from one main control station.
“Although these crews did not face the same challenges as the staff that worked underground, 80 percent of the conveyor and controls work was performed 80 feet in the air,” said James Ruscher, surface general foreman. This same crew was also responsible for installing over one and a half miles of a three-system duct bank, 3 miles of site lighting and 5 miles of conveyor control and illumination conduit.
The site buildings that house the machinery and ancillary systems, including power distribution, HVAC, lighting, fire alarm and security systems, were not extensively designed or engineered, according to Ehmann. O’Connell Electric bid on this part of the project separately and was awarded the contract to design, along with teams from the general and mechanical contractors, and install the necessary systems. “These buildings ranged from simple electric rooms to a 15,000-square-foot maintenance shed and an administration building which houses offices, locker rooms, and the main control center,” he said.
Challenges and rewards
“The most difficult aspect of the project was working underground,” recalled Ehmann. The company handpicked the electricians who had experience in various types of confined spaces and who were willing to do the work. “No one who was asked, refused,” observed Salerno. O’Connell’s project management team was very thorough in building the confidence level of each individual electrician and provided extensive safety training specific to the environment. “We also relied on the general contractors’ years of mining experience, as well as on the miners, who were very dedicated to ensuring that our team remained safe,” Salerno added.
The complexity and length of the project meant that it had to run as smoothly as possible in order to stay on budget. O’Connell set up a site office so that all operations, including estimates, cost analyses and the management of daily operations could be taken care of without delay. “Our goal was to ensure that major decisions and any changes to the project requirements or schedule could be made immediately,” said Salerno. In addition, a temporary shop was constructed on site and used for everything from vehicle maintenance, to prefabrication of systems or PLC cabinet assembly. “As soon as any changes or modifications were discussed, they could be implemented immediately on site,” said Ehmann.
One year after the completion of the mine, American Rock Salt, LLC is operating at peak capability and supplies salt to the northeast, as far south as North Carolina, and as far west as Ohio. EC
BREMER, a freelance writer based in Solomons, Md., contributes frequently to ELECTRICAL CONTRACTOR. She can be reached at 410.394.6966 or firstname.lastname@example.org.