Inside an Oldcastle site with a new wash plant

Oldcastle’s Brett Ballard with the EvoWash 251. Photo courtesy of CDE.

Oldcastle Materials upgraded a quarry in Texas with a new all-in-one dual-pass sand processing plant, making inconsistent production levels and loss of fines to ponds things of the past.

The site in Burnet County, Texas, is part of Oldcastle Materials’ national network, processing raw limestone feed to produce construction materials, including concrete sand.

The wash plant at Burnet was initially equipped with a 44-in. sand screw, a hydrocyclone and a dewatering screen intended to process 200 tph of limestone. However, valuable sand was lost to the settling ponds and the final product contained high levels of moisture.

“After identifying the cause and impact of the inefficiencies affecting our existing equipment, we knew we had to invest in an upgrade to ensure we could operate at full feed capacity and extend the life of our settling ponds,” says Lowell Lindsey, plant manager at Oldcastle’s Burnet Quarry.

Before upgrading to a larger sand screw, though, Oldcastle wanted to check out cyclone technology.

“[It] is becoming increasingly popular in the materials washing industry,” Lindsey says. “We contacted the local CDE office in Cleburne, (Texas), for one of their experts to analyze our material and current production process so they could offer an alternative and more efficient solution to our existing operations.”

CDE did a site audit and sand and equipment analyses to then propose a tailor-made washing solution for Oldcastle’s needs. Oldcastle representatives also visited a nearby site where the equipment CDE suggested, an EvoWash dual-pass plant, was running.

“We were impressed by the quality and performance of the equipment we saw and requested a quote from CDE,” Lindsey says. “Following this, we opted for a CDE solution, and our new EvoWash replaced our sand screw in late 2017.”

The Burnet Quarry’s solution

Another look at CDE’s EvoWash 251. Photo courtesy of CDE.

A dual sand pass EvoWash 251 was offered as a solution with benefits over an original sand screw system. A compact and user-friendly plant, the new system can efficiently process feed material to produce two products simultaneously that are ready for market straight from the belts.

After testing by CDE to determine the proportion of silt material to be removed from the Burnet Quarry’s raw feed, bespoke specification of the cyclone setup was calculated for control over silt cut points.

As an added revenue and environmentally friendly bonus, the retention of all quality fines available in the raw feed translates into reduced maintenance costs and a longer lifetime for the settling ponds.

In addition, with greater than 95 percent separation efficiency achieved, Oldcastle’s Burnet Quarry now produces 200 tph of concrete sand and 40 tph of mason sand at the same time.

The machine’s design means the operator can control the curve of the concrete sand by adding or removing more of the mason sand to reach the desirable grading of the main C-33 concrete sand. Moisture content of the washed sand products also significantly decreased compared to the previous technology, meaning sand can be immediately loaded to trucks without the need to wait for it to further dry in the stockpile.

“We can now fully exploit the available raw feed and produce two high-quality products at the same time, which are dewatered to near-dry levels,” says Brett Ballard, plant manager at Oldcastle. “Our new CDE EvoWash sand processing plant has resolved inefficiencies by capturing the waste slurry flow from our plant that contains fine sand. It now extracts and cleans that sand which is marketed as hot mix or mason sand. This means we can now produce a saleable product out of what used to be waste.”

Oldcastle also needed to maximize the lifespan of its settling ponds. With the substantial reduction in fines lost to ponds, maintenance and downtime decreased drastically – and so have associated costs. The company is now operating to optimal capacity with increased production and product quality, and it benefits from a reduction in costs and an extended lifetime of its settling ponds.