Hanson owns and operates a limestone quarry in Comal County, Texas. Hanson (Gifford-Hill & Company) acquired the operations in 1977 from Servtex Materials Company. Prior history of the site includes two local New Braunfels, Texas, citizens, Ogden and Eikel, who started the quarry circa 1936. Most of the property is within the city limits of the City of Garden Ridge. Garden Ridge did not incorporate until 1970, and few homes existed in the area at that time.
Servtex Quarry is situated on approximately 3,000 acres of land owned in fee by Hanson. The rock quarried at the location, limestone from the Edwards Group, Person Formation, is Early Cretaceous in age. The quarry is located in the Southeastern Balcones Escarpment, within and north of the Balcones Fault Zone.
The limestones were deposited in the Cretaceous sea, within and northwest of a bioclastic belt known as the Stuart City Reef, which consisted of rudists and coral and algal debris. Deposition of limestones north and west of the Stuart City Reef created current resources being mined at Servtex Quarry. The current surface exposure of Edwards-age limestones north and west of the Balcones Fault Zone is called the Edwards Plateau.
Four different geologic formations occur on Servtex Quarry property, including the Person Formation (Edwards Group), the Del Rio Clay, the Buda Limestone, and the Pecan Gap Chalk Formation. Other than a small amount of Pecan Gap clay material used as a liner in the water system, the Person provides the main economic resource at the quarry.
The Edwards forms an escarpment along the Balcones Fault Zone, and numerous formations are exposed. Consequently, various mining operations exist along the escarpment, such as cement (Austin Chalk Formation), aggregates (Edwards and Georgetown), and dolomitic materials used in industrial applications, such as food additives, paint, and drugs. The Edwards Group, the preferred aggregate source due to its durability and strength, is extensively mined in other areas of the state, where conditions warrant and the market supports. Quality of Edwards Group limestones degrades to the north of Austin. Units such as the Goodland Limestone, an Edwards-equivalent facies to the north, exhibit poorer quality and cannot be used consistently for specification jobs in which quality is important, such as structures and highways. The Edwards is a resource that has provided Texas with a steady source of quality aggregates for many years and will continue to provide in many more to come.
The lower Edwards is generally poorer in quality than the upper Edwards, the latter of which Servtex Quarry reserves represent. Development of new quarries in the Edwards has become increasingly more difficult. Home development, regulation, transportation, and site-specific geology have created barriers to establishing new quarries.
Servtex Quarry sold approximately 5 million tons of limestone products in 2003, an average year. Some of the products sold from Servtex Quarry include: Road base, Concrete aggregates, Bituminous aggregates (for hot-mix asphalt), Railroad ballast, Rip-rap and gabian stone for erosion control, Flux stone, Desulfurization stone (used in power plants), Landscape materials, Soils applications, Cement, Deicing materials, Brick and block materials, Manufactured sand etc.
The main products sold at this facility are concrete aggregates. Most of the products sold in 2003 were shipped by rail (70%) and the rest by truck. The Union Pacific Railroad serves the facility, and rail cars are brought into the site regularly for shipment to customers. The market area includes the local area and points east, reaching east Texas and Louisiana. Houston is a large market for the materials. From this operation, material has been shipped as far away as California. Products are handled by trucking companies not associated with Hanson. Hanson owns no over-the-road haul trucks in Texas.
Reserve life at the quarry is currently estimated at 15 to 20 years, with some variability assumed in market demand. The mine plan continues to bring our operations toward the City of Garden Ridge’s development. One of the challenges facing continued viability of the operations is the relationship between residents and quarry, which have been positive. Currently Hanson meets regularly with the resident-based Quarry Commission to discuss and review operational impacts on the community, including the daily blasting that must occur to provide raw materials to the plant.
Once the rock is blasted away from a quarry face, front-end loaders load haul trucks with the shot rock. This rock is hauled to the primary crusher. Rock is then transported from the hopper via conveyor belts to the main plant, where the rock is washed, sorted by size, crushed further, and transported to various load-out bins and/or stockpiles. Rock is then loaded onto trucks or rail cars. Trucks must be weighed prior to leaving the plant, keeping in compliance with load limits on the roads.
Crushing and washing of stone creates an unsellable product that is composed of very fine grains of limestone and clay. This product is pumped to settling ponds, where solids are collected and water is returned to the washing plant. There is no major market for these fines, although some of the materials are marketed from time to time.
Water is supplied by several permitted wells completed in the Edwards aquifer. The site is currently permitted for approximately 1,600 acre ft/yr. This facility has struggled recently with the water pond, where fresh water and recirculated water are stored for use at the plant. The pond has a liner for water retention, and without the liner, water would simply seep into the permeable quarry floor and back into the aquifer below. The pond had become filled with fines because of inadequate settling areas. The problem was recently resolved by our placing dredges in the pond to remove excess fines.
The site has been the subject of several academic studies in landscape management. Various opportunities appear to be viable for the depleted quarry, especially because a large portion of the property will not be quarried and the expanding City of Garden Ridge is adjacent to the site. Some postmine uses suggested include office space, recreation (golf course), industry (use of the rail) and homes. Numerous examples of successful postmine uses are found in similar quarries around the area, such as Fiesta Texas, Quarry Golf Course, Quarry Shopping Center, Trinity University, and many others. Reclamation at this time is not feasible because of active mine operations and lack of overburden materials to contour inactive faces.