RENO -- A multi-million plan to convert the autoclave and roaster at Barrick Gold Corp.’s Goldstrike facility from propane to low-cost natural gas will save the company as much as 60 percent per year on the facility’s fuel costs, company executives say.

Crews from Q&D Construction are laying a 26.5-mile spur of pipe off the Ruby natural gas pipeline that runs through Nevada near the Goldstrike facility at the northern tip of Eureka County.

Completion of the pipeline project in 2011 brought about serious discussion for an extension to the Goldstrike property, says Andy Cole, the site’s general manager.

Q&D will bring the pipe to Goldstrike’s main entrance, and from there Barrick faces an additional project to lay 6.5 miles of natural gas pipe inside the facility to the nearby autoclave and to the roaster on the west side of the mine site. Both ore-processing facilities require extensive renovation to convert from propane to natural gas.

“That is a big part of the project for us — but the important thing is to get it in and allow us to replace the use of propane on site,” Cole says. Among the major stationary equipment to be converted: the boilers, autoclave, carbon regeneration kiln, preheat burners, ore dryers, roaster and incinerator. Because the fuels are drastically different in their physical characteristics and thermal values, the project required a wholesale change of the burner packages used on the equipment, says Mike Eiselein, Goldstrike’s process division manager.

Each burner package will be designed and intended for “plug-and-play” exchange during normal maintenance shutdown to mitigate impacts to Barrick’s production schedule, Eiselein adds.

“It does require some downtime, but we will do that during maintenance down times already scheduled. We will cycle down when we do the conversion, and start it out with gas without really impacting our operations schedule.”

Cost is the main driver of the project. Delivering propane to the site is a 24-hour, 365-day operation requiring two or more trucks per day. The conversion not only cuts down on truck traffic at the site, but it also alleviates potential delivery concerns associated with wicked winter weather.

“There is such a large and plentiful supply of natural gas,” Eiselein says. “We can make a wholesale change on the production equipment and not have to worry about switching back to propane. With the price of propane you can image we are pretty excited about converting to natural gas.”

Energy costs — electricity, propane and diesel fuel — are the mine’s largest expenses, Cole says. Barrick expects to reduce its fuel costs for powering the equipment used by the autoclave and roaster by as much as 60 percent over the next year, and that number could rise as the nation’s gas infrastructure expands, Cole says.

The availability of natural gas also could lead to a wide-scale conversion from diesel to natural gas for Barrick’s huge fleet of massive haul trucks.

“It is a pretty significant capital investment, but the savings are also significant with the current prices of propane,” Cole says. “We run a pretty sizable haul-truck fleet all on diesel, and a lot of manufacturers are starting to look at engines that run off natural gas. We may have a pilot program to test LNFG (liquid natural gas fuel) engines next year.”

The cost differential between propane and natural gas is so great that Barrick expects to recoup its multi-million dollar investment in as little as one year, Cole notes.

The plan isn’t without significant engineering challenges. Among the biggest: Running natural gas pipeline inside the 24-hour mine site. Completing the spur is a straightforward process, Eiselen says, but once the line arrives at Goldstrike it’s got to be buried while avoiding working phone, sewer, water and power lines.

“This site is well developed and has been here for 30-plus years,” Eiselein says. “We have to had to go through and do all sorts of state-of-the art mapping of the sub-surface utilities for the various stuff we have buried.”

There’s also the challenge of circumnavigating the massive Betze-Post pit, the largest open-pit gold mine in the country. The natural gas pipeline inside the Goldstrike mine will cross the active haul road in four places in order to reach the autoclave and roaster.

“It is quite a feat, and it will take a lot of coordination and a lot of engineering design in short period of time, all in the middle of winter,” Eiselein says.