About Highland Growers
Highland Growers started in 1939 as a farmer owned co-op for the local Producers to market their produce. From there they got into feed and fertilizer, in 1968 chevron chemical built a blend plant for us.
In 2011 Highland Growers in DeRidder, LA, replace a wooden blend plant built in 1968. The new facility, a Monolithic dome-shaped fertilizer blend plant measures 75 feet in diameter and includes six bins.
Domes are super-insulated, steel-reinforced concrete buildings that are used for everything from schools to churches to homes.
Monolithic Inc. is an industry leading company which has been building both single- and multiple-use storages necessary in the operation of a blend plant since the late 1970s.
There are several factors that make these buildings uniquely positioned to serve as fertilizer storage units. For starters, the materials used in the domes’ construction make them extremely energy efficient. The geothermal properties of the concrete, combined with the super insulation, keep temperature fluctuations to a minimum.
In fact, it is possible to air condition the facilities using small units, which makes it easier for blend plant operators to keep condensation out of their formulas ensuring little or no product loss. It also makes for a much more pleasant working environment for workers.
The dome’s circular design also offers an advantage for fertilizer blending. All of the needed materials are within easy reach, enabling plant operators to quickly place the specialty chemicals into the weigh hopper for transfer into the exterior blender. And since the domes can be virtually any size, the number of bins can be adapted to meet the needs of the operator.
Finally, the structures are disaster-resistant, meeting the Federal Emergency Management Agency’s criteria for near-absolute protection from tornadoes and hurricanes, and they also are fire-proof. The reinforced concrete shell also makes it easy to secure the facility.
Company President Donald Smith said the ability to affordably air condition the building was a big selling factor for him, as well as the circular design. “We liked the volume you could get in a small area,” said Smith, whose family has been operating Highland Growers since 1939. “The ability to control the humidity is also important to us.”
Construction of the dome is as unique as the building themselves. It begins with the placement of a ringbeam footing and the pouring of a circular steel-reinforced concrete slab floor. Vertical steel bars embedded in the outer ring later attach to the steel reinforcing of the dome itself. An Airform, a tarp made of tough, single-ply roofing material, is attached to the ring base and inflated, creating the shape of the dome.
Crews then move to the interior of the dome, where they spray polyurethane foam on the Airform and reinforce it with a grid of steel rebar. They then spray the dome with two or three inches of Shotcrete. The result is a safe, permanent and energy efficient structure.
“Because the domes are so insulated, we expect virtually no condensation on the interior surfaces, and that’s good because condensation can enter a pile and lead to corrosion,” said David B. South, president of dome manufacturer Monolithic. “We also used special additives in the concrete to help eliminate any corrosion caused by the fertilizer.”
In building fertilizer blend plants, Monolithic used MetaMax, a high reactivity metakaolin that gives the concrete significantly less porosity than standard concrete and makes it resistant against chemical attack.
Super-strong concrete also means less damage from loaders that accidently ram into walls. Front-end loaders, which play a major role in the loading and unloading of fertilizers, also can be hurt by a corrosive environment.
For plant operators who are willing to blaze a new trail, the concrete dome’s unique features offer them the ability to conduct their business more efficiently while also saving money on utilities and replacement costs.