Limestone has many uses. Just ask Carey Haughy, president of Blue Mountain Minerals, a limestone mining outfit north of Columbia.
Anywhere from 500,000 to 1 million tons of the stuff are extracted from the surface mine annually.
The limestone shipped out of Blue Mountain Minerals is a primary ingredient in glass manufacturing; it serves as a calcium supplement for cattle and chicken feed; it’s used in coal-burning power plants to reduce acid rain; and it’s placed on embattled farm soil in the Central Valley to restore its PH level.
According to Haughy, one ton of limestone can: Produce 22,000 Snapple bottles, supplement the diet of 7,000 cattle, help produce 141,000 eggs and treat an acre of farmland.
The finished product — a sandy white powder, mountains of which can be seen at the mine site — is a far cry from its raw form.
The product starts off as boulders of marble, similar to the rocks exposed years ago by hydraulic mining that can be seen throughout Columbia.
Haughy, a geologist by training, pointed out that though most people consider marble and limestone to be very different, their basic constituent parts are the same.
Both have an organic base — largely the shells of ancient organisms; the only difference is marble has been transformed through heat, pressure and time.
The deposit that makes up the source of Blue Mountain Minerals’ mine was once at the bottom of an ancient seabed and is estimated at 360 million years old, Haughy said.
The earliest commercial use of the mine site dates back to the late 1800s, when the rocks were used for the facings of buildings.
“There’s been mining here since right after the gold miners got here — they found the marble deposit,” Haughy said.
Haughy said the marble rocks were used on various structures in downtown Sonora. Rumor has it that a chunk of rock might even have been used in the Washington monument.
A rock was removed once for such a purpose, according to Haughy.
But the days of the mine producing decorative stone are over.
It’s actually because of this that Blue Mountain Minerals has been able to keep profits steady during the current economic slump.
“A lot of mines are for the construction industry,” Haughy said. “But our biggest market is agriculture — people still eat and there’s still population growth.”
Haughy, who is sensitive to criticism about her mine, stressed that though some people don’t like mining, they benefit in some way from the industry.
“The glasses you drink out of, the food you eat — these are what use our limestone,” Haughy said.
The good times could continue for Blue Mountain Minerals, as it has a permit that expires in 2055, with reserves to last.
In all, the company owns 1,200 acres at its site, with 300 permitted for mining.
The employee-owned company is so confident it’s here to stay that it is in the midst of a $1 million-plus upgrade designed to make its operations more efficient.
The upgrade consists of a new primary crusher and conveyance system. The crusher will replace one that dates back to the 1920s.
There are three crushers on site that break down the rocks into increasingly smaller pieces. Rocks dumped into the primary crusher are about the size of an office chair.
But the work to bust up the rocks begins long before they enter the primary crusher. The first step consists of drilling holes in the limestone deposit and filling them with explosives.
Once the explosives bust up the deposit, front-end loaders place the resulting chunks of rock into haul trucks that are so massive their tires alone are about 12-feet tall — and cost $20,000 apiece.
Haughy said Blue Mountain Minerals, which has about 50 full-time employees, strives to be a “good neighbor.” She also noted that it is regulated by various agencies that make sure it follows rules regarding water and air quality, noise and vibration levels, and truck traffic (around 60 to 80 trucks haul product to the Central Valley each work day).
Nonetheless, there has been controversy surrounding the mine in the past.
Back in 2005, proposals to increase the operating hours of the mine’s processing plant and increase production tonnage resulted in an outcry from plant neighbors and an environmental group worried, in part, that more truck traffic and noise would result.
The county approved the plan.