AGGREGATE—WHAT WE MINE

The King Road Mine will produce about 3 million tons a year of construction-grade aggregate—crushed limestone which is an essential material needed to build highways, homes, hospitals and schools in Florida. In fact, the Florida Department of Transportation (FDOT) will be one of the single biggest consumers of aggregate produced at the King Road Mine.

The limestone found in southern Levy County is one of the few sources for this material in Florida, and the King Road Mine will be the only active construction-grade aggregate mine in the county. New sources, such as the King Road Mine, are becoming even more important as reserves are being depleted at many existing mines, and the start-up of new ones can take several years. The FDOT estimates the volume of aggregate produced in Florida will not meet the state’s demands in the next decade without new sources.

Mining is one of the oldest industries in Levy County and in the state. Today, aggregate operations contribute more than $1 billion a year to the Florida economy. On a national scale, Florida is a leading state in the mining and production of aggregate and other building materials; and is the third largest consumer of crushed rock products in the United States. But dwindling supplies and increasing demand could lead to a shortfall of about 15 million tons a year—forcing the construction industry to import materials from other states and suppliers in Mexico, Canada and the Bahamas, most of which don’t have sufficient regulations in place to protect the environment during mining.

The higher transportation and labor expenses needed to bring aggregate in from out of state adds up to greater costs for home buyers and other consumers. This impacts government service providers as well, since the largest single user of crushed stone resources in the state is the Florida Department of Transportation.

By keeping sources local, and continuing to operate regional mines such as the King Road Mine, the overall cost of construction goes down. The Florida DOT has determined existing sources of aggregate will not be able to support Florida’s growth for the next decade. New sources of aggregate must be found. The King Road Mine will help fill the need for locally mined, construction-grade aggregate.

The Florida Legislature recently passed legislation supporting local mines through House Bill 5013, which defined aggregate mining as a “critical industry” in the state. The bill was signed into law by Gov. Charlie Crist in June 2009. The intent of the legislation is to encourage and promote the local production of aggregate to avoid a disruption of supply of this much-needed resource, as well as hold down the overall cost of construction projects in the region.


EXTRACTING THE AGGREGATE

Tarmac plans to mine about 25 acres per year, starting with excavation on the east side of the property. Extracting the limestone will require blasting to loosen the rock. Tarmac will meet or exceed the stringent regulations set by the State Fire Marshall, and blasting will have no impact on the surrounding community. In fact, a series of test blasts at the King Road Mine site showed the vibrations were not even picked up by seismograph instruments set up in nearby communities.

Blasting at the King Road Mine will occur about once every week or two. Each blast is actually a series of smaller blasts timed closely together. This minimizes vibration, and the entire event only lasts about two seconds. Food grade mineral oil is used in the blasting process, so there will be no adverse impact on water quality. No explosives of any kind will be stored at the King Road Mine site.


TURNING LIMESTONE INTO CONSTRUCTION-GRADE AGGREGATE

As the mine site is excavated, limestone will be scooped up by a machine, and stockpiled on the edge of the lake to allow the water to drain off. After about 30 days, the rock will be taken by conveyors to the plant where it will be crushed, screened and washed to make various grades of aggregate stone. The area where the limestone is extracted will naturally fill in with water, developing lakes that will provide the water to be used in the mining operations. Nearly 99 percent of water used in the mining process will be re-circulated back into the mine site.