The Cat 992K wheel loader equipped with a 15 cu. yd. bucket moves overburden material.
The predominant image of gold miners in most people’s minds is probably one of old prospectors panning for the precious mineral in a river or stream — maybe in California or Alaska.
They most certainly don’t think of state-of-the-art, industrial-scale gold mining in, of all places, South Carolina.
Yet that is exactly what is happening at a nearly 200-year-old mine near Kershaw, in Lancaster County about an hour northeast of Columbia.
Decades before the California Gold Rush in the 1840s, numerous working gold mines were operating in the Carolina Slate Belt. These mines eventually played out or became uneconomic.
Now, thanks to new methods and technologies, the Haile Gold Mine (HGM) will get a second life.
And one thing is for certain: HGM is decidedly not being manned by a bunch of prospectors with pans.
Company Bets Big on Gold Mine
Romarco Minerals Inc., an exploration and development company headquartered in Toronto, Canada, acquired the Haile mine in 2007 and has since invested more than $330 million in its operation. The Kershaw site is the company’s flagship operation.
The mine has gone through various owners over the years, with several different firms working the site in just the last 40 years. The last actual production ended in 1990, but according to Brent Anderson, Haile’s Mine Manager, none of the previous efforts were as large as what his team has planned.
“Our geology team, led by James Berry, has worked hard since 2007 to re-interpret the geology to understand where the gold is located,” Anderson said from his office on-site. “They have discovered new deposits and new areas that were unknown to previous companies that had been here. A lot of the previous companies only drilled shallow holes and as soon as they hit the sulfide mineralization they quit because they didn’t have an economic way to extract it.”
In contrast, Anderson said that one of Haile’s seven planned pits, the Ledbetter, is “about 900 feet deep and the underground potential is a lot deeper than that.”
Although no gold has yet been extracted from the mine since Romarco acquired the property, Haile is carefully planning for that day in the next two years by working on a myriad of pre-production activities essential to successfully get gold out of the ground.
A Mine of
In the last eight years, the Haile team completed a lot of exploration drilling. To date, some 4,000 drill holes have been drilled on the property, totaling nearly two million feet. A feasibility study commissioned by the company revealed the mine’s great potential, leading Haile to move full-speed ahead with a project life of 14 years, Anderson explained.
“We have an 18-month pre-production period and that time will be used to construct the processing facility and develop the mine,” he said. “We plan to mine 16 million tons of material during pre-production and, after that, we will be able to provide sustaining ore to our processing facility. During that year and a half, we will encounter 150,000 tons of ore which will be placed into a stockpile and, once the mill is up and running, that ore will be processed.”
Anderson added that when the mine is fully operational, 7,000 tons of ore a day will be sent to the mill every day of the year. Those 2.5 million tons per year will produce an annual rate of about 150,000 ounces of gold.
It is a labor-intensive and expensive procedure, but the rewards can be very lucrative. That is why a well-funded company with highly-trained experts on its team, like Romarco, will successfully operate this world-class project. By the time HGM pours the first ounce of gold, the company will have invested more than $650 million.
New Technologies Lead to Better Yield
Why was Romarco interested in seriously working this mine when others were not?
Anderson answered that they decided they could be successful using more economic methods of getting the gold, such as employing a standard processing technique called flotation.
Using this method, ore is delivered to a jaw crusher that will reduce it to a minus 6-inch size. From there it proceeds to a SAG (semi-autogenous grinding) mill, which utilizes 5-inch steel balls within the machine to grind the rock to the consistency of sand (Autogenous means that the rocks are ground against each other; semi-autogenous means that the rocks grind against each other and the steel balls).
That material then goes to a cyclone, which separates the finer particles from the coarser particles, Anderson explained. The finer material is sent straight to a process that turns it into a flotation concentrate, while the coarser material goes to a ball mill first to be made fine enough for that process.
“In order to understand flotation, just think of a bathtub full of soap,” Anderson said. “If you blow bubbles through it, it has a nice froth on the top. The sulfide minerals in the ore like to stick to that froth and if you capture that, you have a sulfide concentrate. Most of our gold is associated with those sulfides — that’s where most of the values are. We will re-grind that concentrate to 13 micron, about the diameter of a red blood cell.”
By grinding the ore that fine, Anderson continued, the gold is easily liberated in a solution of sodium cyanide, which is a standard technology for leaching precious metals. That allows his team to recover about 84 percent of the gold in the ore.
“The ultra-fine grinding technology is fairly new and prior to its use, extracting the gold required a thermal process that was very expensive — not economic at the grades we are looking at here at Haile,” he concluded.
Blanchard Gives Reliability to Haile
Haile plans to remove the deposits using standard open-pit-mining techniques: drill, blast, load and haul. In order to send 7,000 tons per day to the processing facility, the average total mining rate is about 60,000 tons a day. Anderson’s crews will first drill and blast the rock into fragments, making it easier for a Hitachi excavator and a pair of Caterpillar wheel loaders to dig out and load onto haul trucks.
“The two wheel loaders are a Cat 993K and a 992K, while the excavator is a Hitachi EX1900,” Anderson said. “We selected Hitachi for its performance in poor underfoot conditions. It floats better in the mud than a wheel loader does. It also has a little higher breakout force, but the wheel loaders provide a lot of flexibility. We also like the flexibility and mobility of a wheel loader doing stockpile duty.”
Besides the Hitachi, though, most of Haile’s other equipment is made by Caterpillar, which the mine buys from South Carolina’s Blanchard Machinery.
For instance, Haile has a fleet of 12 100-ton Cat 777F off-road trucks, as well as two smaller capacity 773F trucks. On the support side, a Cat 988 wheel loader is slated to work specifically with the 773s to pioneer, or open, the mining pits as smaller working areas demand smaller equipment.
Then there are D9 crawler tractors being used to develop the mine and construct haul roads, Anderson said.
“Haul road construction and maintenance is very important to us,” he explained. “Since haulage is nearly half of my cost I need to have proper roads to keep my rolling fleet in top shape and my costs low.”
A variety of other Caterpillar pieces are used at Haile, including two M series motorgraders, an 834H dozer, 336D and 336E excavators and three MD6280 rotary drills. There also are smaller maintenance support equipment such as a water truck utilizing a 773F chassis and sporting a 13,000-gallon Magnum tank and spray unit. Additionally, Anderson has a Cat 740 articulated truck with a 5,000-gallon fuel tank and full-lube service tanks designed to service the mine’s field equipment.
“In my experience, after-sales support is a very important part of maintaining and operating our line fleet and I have found that Caterpillar and Blanchard offer superior efforts in that respect,” he said.
Just Being a
The Haile project will have an economic impact to Lancaster County in the amount of $68 million per year.
HGM also has begun planning for the day when its gold mining operation there is finished.
Forest and wetlands are located all over this part of South Carolina, including at the gold mine site. Anderson understands that his company has a great responsibility to make sure the natural beauty of the land is restored when the mining is completed.
To that end, he expects Haile to spend more than $90 million on mitigation, restoration and reclamation. That will include re-vegetation and installing pit lakes and recreational areas for the public to enjoy.
“Frankly, the area will be improved when Haile is done,” he said. “The previous owner did a great job of reclamation on this property but there were some other areas that they didn’t control that were left un-reclaimed and we will intend to reclaim them, too, when we are done. That means re-establishing the wetlands and streams that we’re impacting.”
To prove its good stewardship of the land, Haile is posting an up-front financial assurance bond of approximately $55 million to ensure that reclamation will be performed.
“We are very proactive and believe it is an important part of doing business,” Anderson said. “We all live here and we want to be good neighbors to our friends in the Kershaw community. That is simply a part of our operating philosophy.”