A New Water Recycling System at Cemex’s Balcones Quarry Allows the Operation to Use 90 Percent Less Water Annually.
By Mark S. Kuhar
This is the third in a three-part series on Cemex’s Balcones Quarry in New Braunfels, Texas. Last month’s article focused on the plant’s production equipment. – Ed.
Cemex’s vast Balcones quarry near New Braunfels, Texas, began operations in 1968 and is one of the top aggregate operations in the United States, producing approximately 10 to 12 million tons of limestone materials. The quarry currently employs more than 100 people and is largest crushed stone quarry by production volume in the United States, according to the U.S. Geological Survey.
Balcones Quarry, as you might imagine, uses a lot of water. In the arid expanses of the Lone Star State, that consumption was seen as untenable. So the company installed a new water recycling system that reflects commitment to sustainability by reducing reliance on local water sources and lowering operational costs.
The system decreases the company’s environmental impact and reliance on water pulled from nearby sources by using 90 percent less water annually than previously used by the quarry’s wash plant.
The new, fully-automated water recycling system uses and recycles 12,000 gal.-per-min. of water to separate aggregate sand fines, which are then reclaimed from the water stream as useable sand product. The water recycling system decreases the need for additional local water and adds efficiency to wash plant operations.
Getting Started
“We were building a new stone processing/wash plant and realized early on that we needed to supply the new wash plant with a reliable, high-volume source of good quality and consistent water,” said Lance Griffin, director of aggregates – Texas and New Mexico Region. “I was chosen to lead that effort based on my past experience as a mining engineer and industry contacts.”
This was not a simple task. While some quarries might be able to get away with bolting on some strategic equipment to meet their needs, this project called for a large-scale effort.
“We first approached the project on what we thought we were going to need in terms of water flow and water quality,” Griffin said. “In terms of options, we looked at equipment that might be available within the Cemex network. Along with seeing what equipment was available in the network, the thought was to design a plant using proven principles rooted in “old school” mentality.
When thinking “old school” the idea was to utilize the time-honored principle of gravity.
“Balcones designed the water recycling/sand plant and tried to utilize gravity flow where possible,” Griffin said. “Ease of operation and maintenance, environmental compliance and expandability were all important considerations.”
Lots of Equipment
The new wash plant features the following equipment:
- Schurco slurry pumps.
- National Pump vertical turbine pumps.
- Red Valves pinch valves.
- Paschal dry polymer system.
- Abresist cyclones and piping.
- Krebs G Max cyclones.
- McLanahan sand screws (see photo at left).
- Azfab and McLanahan thickeners.
- Square D MCC.
- Lightening Masters lightening protection.
- Toshiba VFDs.
Balcones had two existing McLanahan Twin 44-in. screws on the property operating continually with good results, and it only made sense to move these to the new sand plant for continued trouble-free operation.
The wash plant process flow works like this. The fully automated water recycling and sand plant receives its process water from the Balcones wash plant. The process water, which contains all the underflow from the wash plant, is first pumped through twin Schurco 10 x 12 pumps to four Abresist cyclones for the processing of manufactured sand.
The nearly on-spec sand from the cyclones gets its final cleaning from within the McLanahan sand screws. The underflow from the Abresist cyclones and sand screws is then pumped from another set of Schurco pumps into the Krebs G-Max cyclones for the production of an ultra fine limestone product. The final underflow produced from the ultra fine cyclones flows via gravity to both thickeners for final densification and storage.
“The advantages of this water recycling/sand plant system are huge in south central Texas,” Griffin said. “South central Texas is seeing tremendous growth in its population base and therefore, stressing the local Aquifer, along with other resources and infrastructure. Less water is required to operate the plant, and the water saved is made available for use by the local utility.”
Exceeding Expectations
The water recycling/sand plant has exceeded expectations and has proved very reliable.
According to the U.S. Census Bureau, New Braunfels was the nation’s second-fastest growing city among those with more than 50,000 residents. The new recycling system will save the equivalent of 2,000 Olympic-sized swimming pools annually.
“This project represents Cemex’s continued commitment to integrating safety and sustainability practices into our operations and to minimize our environmental footprint in the communities in which we live, work and operate,” said Ignacio Madridejos, Cemex USA president. “Our team has driven day-to-day activities to ensure the safety and well-being of our employees while also applying industry-leading environmental management practices in our Balcones operations, and we’re extremely proud of their diligence.”