Articles & News
Articles & News
- Posted on
- by Rebecca Pyper
The sophistication of coal storage keeps increasing. Once considered dirty and environmentally hazardous, structures are now built with tight emissions […]
The sophistication of coal storage keeps increasing. Once considered dirty and environmentally hazardous, structures are now built with tight emissions control, minimal to zero product interaction with the outside world and innovative utilization of byproducts that used to be destined for landfills. Coal is a resilient industry that keeps adapting to stay relevant.
Even as the industry sees proactive change, a few things remain the same, and one of these is that domes are well suited for coal storage. To help coal companies plan the ideal project, Dome Technology relies on this simple rule of thumb: The type of coal determines the reclaim, and the type of reclaim determines the dome shape.
Coal types and reclaim options
With subbituminous coal, storage and handling requirements are stringent. Based on volatility, coal companies must decide how they’ll maintain access to the pile for handling potential fires and hot spots. A doughnut-shaped pile is a good option for storing subbituminous coal. The pile is placed and reclaimed using a stacker reclaimer; this model allows access to the pile and can work particularly well when the cleanout happens every couple weeks. A monitoring system on the inbound conveyor is another must so hot coal is rejected before being placed in the storage. Fugitive dust cleanup is also essential to proper storage and avoidance of fire and explosion concerns.
A kidney-shaped pile can also work well. The stacker creates a pile that tapers off on the side, and the filling arm’s swing is 230 to 250 degrees. This shape provides ample access to the pile, so while it might not make the most of a dome’s capacity, it does provide peace of mind and safety when managing and monitoring a volatile product.
With bituminous and lignite coal, stacking and reclaim options are expansive. From front-end loader to stacker reclaimer or drag chain, coal producers can be choosy, balancing low cost with sophistication. Dome Technology’s team has also seen rotary plows with cone-shaped piles as an effective reclaim option, and another effective choice is tall domes with a live-bottom floor to keep product rotating.
Reclaim options and complementary dome types
For a reclaim system to work best, the dome must be built to complement it. Subbituminous storage is safest within a hemispherical dome with easier hot-spot access from the inside of the storage, but the inside shape of the dome must be engineered accurately too. For instance, with a stacker reclaimer, the shell is built to account for the reclaim arm being fully extended without scraping the dome wall. Typically, the dome is built with a short stem wall and a pedestal upon which the stacker reclaimer sits.
This model can leave pockets of product behind on the floor, so the dome floor is often built with a slope to ensure product can be mostly reclaimed to the tunnel hopper instead of building up in hard-to-reach spaces.
Bituminous, anthracite or lignite coal all benefit from stacker or live reclaim. When a 100-percent live reclaim system is selected, the dome can be taller and smaller in diameter—an ideal model for sites with less construction space. If a stacker is selected, a hemispheric dome with a short stem walls is recommended.
Every coal dome is customized so reclaim and dome type work hand in hand. For one potential customer working with bituminous coal, Dome Technology recommended four tall domes with 80 percent live reclaim that feeds three below-grade tunnels and affords the ability to clean out the rest with front-end loaders. With these domes holding 60,000 metric tons apiece, the company could achieve its intended goal of moving 4 million tons a year, or about 76,000 tons a week, all thanks to a solid plan at the front end.
“Once we know the type of coal, that will push the type of reclaim, which will push the dome shape, and then we design it to fit it on the site if possible,” sales manager Lane Roberts said.
Dust control: The benefits of a sealed envelope
A reinforced-concrete storage dome is a natural choice for companies eager to minimize environmental impact. Dust is a concern with many stored products, but it can’t escape a monolithic concrete dome since joints or seams don’t exist. Inside, the truss-free interior discourages dust build up, and a host of dust-control systems exist in the marketplace to manage dust production. Automatic dust-collection systems can be designed to convey dust back into the product stream.
Sealed and seamless, a dome keeps product inside and prevents interaction with the environment. This envelope is multi-layered; a dome is built using the shotcrete method, so concrete is sprayed in place without any construction joints. On the exterior, a high-strength PVC membrane covers the entire structure. Between the membrane and the concrete, urethane foam protects the life of the structure as well as the stored product.
The PVC membrane ensures complete waterproof protection for the reinforced concrete shell and, consequently, the material stored within. A mold-resistant UV-protective resin coats both sides of the membrane, providing long-term protection from these two common sources of degradation. No other silo option offers this type of waterproof protection, and this exterior requires almost zero superficial maintenance.
Domes are always built without rivets, fasteners or mechanical connections found in other storage, thus eliminating potential sources for leaks and rust. This comprehensive approach to waterproofing promises long-lasting protection for stored product and the structure itself.
The double curvature of a dome provides strength at all points of the structure, even near the apex. With strength at the top, a coal company has no problem securing adequate space for dust-collection systems.
Structural strength
The dome itself can survive a disaster other types of storage might not and will likely reward companies with insurance-premium savings. A dome has inherent strength other bulk-storage structures do not. Should an earthquake, tsunami, hurricane or tornado occur, the structure has a better chance of survival than a traditional building.
In a deflagration event, a dome’s round shape channels energy out with less structural damage. Historically, square and rectangular explosion venting has been the norm in storing products prone to deflagration, but Dome Technology’s team has pioneered a round hybrid model that began to be installed on projects in 2016. Whether a pre-manufactured rectangular panel or a metal cladding piece, a squared-off panel creates a weak spot. Round panels are preferable because there are no sharp corners for stress concentration in the structure. This allows for a release of pressure, protecting the structure.
The proprietary explosion vents are comprised of a circular geodesic steel lattice covered with the same PVC fabric used in the dome construction process. The panel is anchored to the dome with explosion-venting relief screws that remain secure during the design dead, live and wind loads. But in the event of a deflagration event, the screws release the panel and allow for the release of the excessive internal pressure. The system is watertight and meets the required operational design loads.
When an explosion occurs, the fabric accepts the load and transfers it uniformly around the ring’s circumference. “Because it’s circular we can predict the load going to each of the fasteners really well,” said Jason South, Dome Technology Vice President of Engineering, Research, and Development. “If it were rectangular, the pressure going to each fastener could be different,” and more difficult to estimate.
Each explosion vent is unique to the project. Dome Technology’s engineering team uses discrete finite element modeling and computational fluid dynamics to model the potential explosion event and determine the amount of open area required for the blast panels such that the pressure only gets to a certain level before fasteners release.
Lessons from China Coal
When Dome Technology CEO Bradley Bateman met with China Coal management, it was clear what the company wanted: a high live-reclaim system at an economical price—and good looks didn’t hurt either.
China Coal sought storage facilities for both its Hulusu and Menkeqing coal mines, located fifteen miles apart in north China’s Inner Mongolia province. Based on “their ability to keep out outside moisture,” Bateman said a series of domes was a more economical solution than traditional silos. And in the land of the yurt, another factor “was the aesthetics; it was the way they look,” he said.
Dust buildup is always a concern with coal storage, and China Coal took it seriously. Since domes are built without the use of interior supports, dust build-up on trusses isn’t a concern. Secondary explosions—the kind caused when initial explosions shake loose accumulated coal dust—are less likely because the support-free domes have no ledges for dust to build up. “One of the major dome advantages is to prevent fire because there are no interior shelves to collect dust, and China Coal liked that a lot—for them it was a big deal,” Bateman said.
Other design features are key to fire prevention. To render the pile of coal inert, China Coal can seal the domes at top and bottom to cut off oxygen sources and pump nitrogen inside to lower the oxygen level. With a thermal scanner over the belt on the inbound receiving side, infrared cameras check temperatures on coal, while on the belt, to make sure no off-spec product enters the dome. A linear heat cable monitors for fire on the belt, also examining bearings in case one is throwing sparks; this cable might detect a fire travelling along the belt length before it reaches the thermal scanner. A product unique to combustion-prone materials, this system shuts down conveyance and alerts facility management of the fire. Depending on the setup, workers can either extinguish the fire, or an existing fire-suppression system takes care of the problem.
Today visitors to one mine will see three domes housing 60,000 metric tons of coal apiece and in the distance three identical domes at the other mine. An innovative material-handling system gives China Coal the ability to move product fast. Inside each dome, a full hopper system similar to a series of funnels situated side by side allows coal to flow through the structure under its own weight rather than by loader.
Other design details also add value, especially since the possibility of coal self-igniting in the dome was one of China Coal’s main concerns, said Zhao Jiapeng of China Coal. The exterior PVC membrane prevents moisture from contributing to spontaneous combustion. Secondary explosions are less likely because the domes have no ledges for dust to build up. China Coal can also render the pile of coal inert by sealing the dome and pumping nitrogen to lower the oxygen level.
The project wrapped in August 2015, a true joint effort between China Coal and Dome Technology. “The achievement from the Menkeqing and Hulusu projects belongs to both of our corporations,” Zhao said.
Dome Technology’s domes allow companies to build storage that meets green regulations now and into the future. The dome is an out-of-the-box, customized solution for companies hoping to grow business while acting as a better steward of the environment.
By Rebecca Long Pyper for Dome Technology
Editor’s note: This article was published in the third issue of World Coal 2021.
- Posted on
- by Rebecca Pyper
Durability. Innovative foundation systems. More storage in a smaller footprint. And simpler product loading and unloading. These benefits have been […]
Durability. Innovative foundation systems. More storage in a smaller footprint. And simpler product loading and unloading. These benefits have been enticing coal, copper, limestone, molybdenum, potash, bentonite, and other mining companies to choose dome storage for decades. And with systems increasing in sophistication all the time, companies who select a dome invest in longevity too.
Two bulk-storage options dominate the mining industry today: domes and flat storage (warehouses). When choosing a storage facility, companies should consider necessary capacity, site conditions, stored-product requirements and features built into the two options.
Space requirements and storage ability
The first Dome Technology domes were hemispherical—they required a large footprint, and their diameter was greater than their height. This model is still the go-to option for mining storage, best where capacity is king and land is inexpensive.
Domes store a large volume in a smaller footprint, stacking product deeper and taking up less property at the site. While some customers require three to five warehouses to store product, a single dome will likely accommodate the same amount of material. The double curvature of a dome lends itself to the ability to build up, rather than out, and the curve provides strength at all points of the structure. Because domes are monolithic structures, any forces interacting with the dome are distributed evenly through the shell rather than being concentrated to weak areas like corners or joints. This gives the dome a longer life cycle than a steel structure. Also, the dome’s ability to sustain large loads at the apex means ample support for head houses, fill conveyors and dust-collection systems.
Flat storage in general requires a larger footprint since product is usually stacked a maximum of 20 to 30 meters deep. Customers can expect a warehouse to utilize 100 to 150 percent more area than a dome holding a similar amount of product. Of course, each dome is planned with the stored product in mind and maximized for optimal capacity and product protection.
Case study: Climax Molybdenum
Climax Molybdenum needed ample storage at its Leadville, Colorado, mine, but there was a catch: To make this project economically feasible, the new structure had to utilize an existing conveyor system and be robust enough to hold the weight of the conveyor, headhouse and expected snowfall.
After seriously considering another type of dome, a monolithic concrete dome from Dome Technology was selected. A dome capable of storing 130,000 metric tons was built to accommodate an existing conveyor system, which was reassembled to feed directly into the apex.
Cost savings, then, were twofold: The customer reused an existing conveyor system, and additional costly support systems were not required to share the load. “Utilizing the existing equipment yielded tremendous savings for the customer,” Dome Technology operations manager Brent Hardy said.
The dome’s strength provided another advantage. With its location in a snowy clime, the structure was engineered to surpass a snow load of 5.27kN/m2 (110 PSF) while supporting the apex mechanical load. A different type of free-span, column-free storage facility could not support a similar load on its own.
“It’s very difficult to find a storage building that can bear the weight of the snow load and the conveyor load at the same time, but the dome can accomplish that,” said Dome Technology Vice President of Operations Dan South.
The project came with other challenges too. At an elevation above 3,353 meters (11,000 feet), weather conditions suitable for building would last just four months of the year; since a dome’s rapid construction process is ideal for quick construction, project managers and crews maximized workdays to expedite construction and complete the job within the amount of workable time.
Dust control was another concern, and the dome’s seamless storage capabilities would easily contain the product, reducing dust throughout the site and the minimizing the environmental impact.
Foundations
Flat storage is often built with concrete wall topped with a wood or steel structure. Because flat storage is constructed of different materials, any differential settlement will cause the “pieces” to separate. A deep foundation is often necessary unless the structure is built on firm ground.
As dome engineers have become savvier, foundation options have increased. A dome’s strength and geometry provide a tolerance for differential settlement—an important consideration for heavy materials.
Geotechnical engineering and site analysis ensure proper foundation performance. In contrast to a flat storage, the dome is continuously supported by the ring foundation; as a result, some differential settlement doesn’t adversely affect the structure, where some differential settlement in a flat storage is generally not acceptable.
In a dome, sometimes a ringbeam is the only necessary foundation system, and customers can save millions when a dome’s deep foundation is reduced or eliminated. But when more stability is required, companies have options:
- For sites with preferable or acceptable soil conditions, a ringbeam provides a shallow foundation alternative. Where applicable, the frost depth will determine the ringbeam’s depth, but usually the ringbeam is placed two to four feet in the ground.
- For sites where the top six to eight feet of ground is of less-than-ideal material, crews excavate the material, replacing it with controlled structural fill. This model allows for some settlement, but the amount will be within tolerable parameters for a dome.
- When the top 15 to 50 feet of soil is questionable, stone columns are often an option. First, crews use an auger to remove earth in about a 30-inch diameter hole until a more stable, soil-bearing layer is reached. Rock then fills the hole and is compacted, increasing the stiffness of the soil below the dome.
When deeper foundations are required, other systems are available. Dome Technology’s engineering team can identify the solutions most likely to work for a project.
By Rebecca Long Pyper for Dome Technology
Editor’s note: The preceding is an excerpt from an article published in the September 2021 issue of Global Mining Review.
- Posted on
- by Rebecca Pyper
The dome’s versatility is winning the attention of school districts nationwide as a growing number contract with Dome Technology for […]
The dome’s versatility is winning the attention of school districts nationwide as a growing number contract with Dome Technology for new schools. To date, Dome Technology has built more than 30 schools and school facilities like gymnasiums and auditoriums. The list of benefits is long and varied, and here are some of the highlights:
Utility cost savings
The insulated nature of a dome yields significantly reduced utility bills. Monticello Montessori School in Idaho Falls, Idaho, is comprised of two domes The ability to reduce utilities costs is an important advantage; according to administrator Erica Kemery, “we have excellent temperature control”—fans are rarely turned on to cool the school, she said.
In a comparison between Monticello Montessori and traditionally built Woodland Hills Elementary less than one mile away, Monticello paid an average of 27.7 percent less in heating and cooling costs per square foot over four years.
Flexible square footage
Because a dome is self-supporting, the truss-free interior is naturally an open space. This allows schools to maximize square footage for large open spaces like gyms or auditoriums without requiring pillars or beams. If administrators later want to add or remove walls or partitions, changes require no engineering of the dome shell.
Ultimate safety
When storm clouds gather, students have a safe place to gather. Windborne debris, projectiles, and 250-mph wind speeds are no match for a dome engineered to combat weather events, and our domes exceed FEMA 361 and ICC-500 standards. That means construction in some regions are eligible for FEMA funding. Click here for details.
The construction materials make domes ultra safe. The airform acts as an impermeable membrane that keeps moisture at bay. The insulation and concrete shell provide better climate control inside. Combined with steel reinforcement and nature’s perfectly strong shape, the structure is undeniably robust.
Dome Technology has built dozens of storm shelters in the United States’ tornado alley and in areas prone to hurricane. Many schools choose domes for their dual purpose; it’s a storm shelter in an emergency and a large facility for school functions the rest of the time. For more information on a few of these projects, click here.
- Posted on
- by Rebecca Pyper
For grain companies where construction schedules typically depend on warmer temperatures, there’s another option. A Dome Technology dome can be […]
For grain companies where construction schedules typically depend on warmer temperatures, there’s another option. A Dome Technology dome can be built any time of year, with work marching right through the calendar.
The industry norm is for new grain-storage projects to wrap up right before harvest. In contrast, a dome can be finished early in the calendar year, providing plenty of time for commissioning before product shows up, said Dome Technology sales manager Heath Harrison. “With a winter-build schedule, it can allow for several months of utilizing the new structure, getting staff used to it, finding the efficiencies, (and) fixing any potential issues before farmers start rolling in from the field,” he said.
Making the most of the off season starts with proper planning in summertime. Dome Technology then completes foundational concrete work before harvest while temps are pleasant. If new storage is being built in an area that is not impacted by the harvest, construction continues until completed, regardless of the weather. But if the site must be sensitive to the harvest, construction crews leave during harvest, then come back and complete the project during the winter.
The all-weather schedule works because a dome is built from the inside out. Once the outer membrane is inflated to create the dome shape, rebar and concrete are applied to the inside; once rigid, construction continues within the structure. Because of this method, “customers hardly know we’re there because the only impact is concrete trucks coming in and out; other than that, all the construction is inside the inflated airform,” or membrane, Harrison said.
Domes have long been built in frigid climates. Some Dome Technology projects have taken place in arctic regions while temperatures were below zero. Robust composition helps the team control the climate inside the structure while work is underway.
The interior is where customization reaches its apex. Aerated systems work well within a dome, and the structure can be fitted with full monitoring systems like temperature cables and gas-monitoring sensors. Fill tubes are always an option, and so are either above- or below-grade tunnels for any size dome.
The no-entry aspect of domes is a critical component in safe operations. No-entry reclaim systems are possible for domes up to 90,000 tons or 3 million bushels, and a bin sweep can be installed in domes as large as 200 feet in diameter. “That’s going to maximize safety and efficiency, especially in this day and age where it’s hard to find labor. Now you’re using one person instead of three to five,” Harrison said.
Also, full automation is always an option, regardless of dome size. Although no-entry systems are capped at 3 million bushels, a dome can be built much larger than that. All domes provide a sealed envelope that protects food-grade products and allows for ultimate flexibility in controlling the interior climate.
By planning a project early and taking full advantage of all 12 months of the year, new construction will be less stressful, less rushed, and better aligned with a company’s exact specifications. “The dome is really fully customizable to the customer’s needs,” Harrison said.
By Rebecca Long Pyper for Dome Technology
Editor’s note: The preceding article was published in the April 2021 issue of Dry Cargo International.
- Posted on
- by Rebecca Pyper
Dome Technology produces videos showcasing innovative projects; currently 21 videos featuring industrial projects are available in our online library. The […]
Dome Technology produces videos showcasing innovative projects; currently 21 videos featuring industrial projects are available in our online library. The most recent videos highlight our work building a DomeSilo for McInnis Cement in Providence, Rhode Island, USA; a seismic-resistant dome for BSA Cementos in Santiago, Chile; and silo repair and recoat work for grain-provider Gavilon. Additional videos are in the works for late 2021.
These videos illustrate Dome Technology’s scope of work on each project. Customer need, new features and concepts, problem-solving systems, and infrastructure details are accompanied by imagery and, oftentimes, customer testimonials. View our available videos here.
- Posted on
- by Rebecca Pyper
Dome Technology is actively expanding its scope of expertise, and one of the most recent storage models added to the […]
Dome Technology is actively expanding its scope of expertise, and one of the most recent storage models added to the catalog is water tanks.
“We have a tank that will save municipalities significant money,” said Dome Technology sales manager Daren Wheeler. “Our building method is just more efficient with less waste. It’s a win for taxpayers.”
Dome Technology’s AWWA D115 tank is built with this process: The foundation is established, and an airform fabricated in the exact shape of the finished tank is attached to the foundation and inflated with high-power fans. The vertical stem walls are sprayed with concrete, as is the low-profile domed roof. Post-tensioning tendons are attached to the vertical wall, along with typical reinforcing vertical and horizontal rebar. Concrete is sprayed to embed the tendons.
A polyurea coating is applied to the entire interior, and the domed roof is closed with a hatch and ladder up the side for access. The tank is then disinfected and ready for use.
Dome Technology liquid storage tanks can be built in any weather conditions and compete with AWWA D110 tanks in cost and construction time.
The difference in Dome Technology’s liquid storage tanks shows up in the pre-stressing. Instead of wrapping the post-tensioning wire around the outside, it is embedded in the tank’s walls, resulting in a seamless, robust structure.
- Posted on
- by Rebecca Pyper
Conveyance is a critical, massive element in any bulk-storage project, and Dome Technology’s team has decades of experience designing and […]
Conveyance is a critical, massive element in any bulk-storage project, and Dome Technology’s team has decades of experience designing and installing custom reclaim systems meeting client needs.
Such was the case with the 2020 Barrette-Chapais project in Port of Saguenay, Quebec, Canada. Pellets are produced at a plant nearby, and upon arrival at the storage facility, they are dumped into a truck-unloading hopper and conveyed to a bucket elevator, which delivers them to a reversing conveyor on top of the domes.
The domes are situated on a hillside some distance from the water, so the outbound conveyor on the reclaim side is incredibly long—1,153 feet (351.4 m) total, reaching 357 feet (108.8 m) to collect product underneath both domes and then stretching 796 feet (242.6 m) to ships that will deliver it to Europe.
Another example of clever conveyance customization showed up in McInnis Cement’s Rhode Island project. Piping on the loading side needed to be routed up and over an existing warehouse; it was then anchored to a structural stair tower as it climbed to the dome apex. Load bearing on the warehouse wasn’t an option, so a new truss and structural-steel supports carry the weight. Part of keeping operating costs low comes from the system’s ability to keep product flowing. A dome with automatic reclaim allows McInnis to offload a ship while simultaneously reclaiming—no need to pay demurrage costs.
“What that’s going to allow us to do is to offload to the dome without having to stop. So it will drastically reduce our unloading costs,” said McInnis project director Dominic Demers. McInnis Vice President, Sales and Marketing, Francis Forlini agreed, adding that this new system reduces operating costs by not having to double-handle product inside the warehouse.
Companies interested in exploring custom conveyance are welcome to discuss projects with our sales team.
- Posted on
- by Rebecca Pyper
On July 11 billionaire and space enthusiast Richard Branson returned from his mission 50 miles above earth to Spaceport America, […]
On July 11 billionaire and space enthusiast Richard Branson returned from his mission 50 miles above earth to Spaceport America, the campus where Dome Technology built a fire station when the facility was developed.
Dome Technology was contracted to build the fire station featuring an organic design that captures the feel of space exploration and complements the landscape. For improved function and a futuristic feel, the dome was built with large openings, including a 30-foot cantilevered “eyebrow” shell within the dome structure. The exterior was finished with sand-colored tiles to blend with the surroundings.
“The design of the fire station fits well with the design of the Spaceport and the overall design environment which was trying to be achieved,” said T.J. Allard, who oversees protective services at Spaceport America for Fiore Industries, a company contracted to provide protective services for the campus, including all firefighting services.
Construction was complicated by a remote job site just west of the U.S. Army White Sands Missile Range. Project success was dependent upon Dome Technology’s team working closely with general contractors, the owner, and the local workforce. The site was also located on a corridor for ancient Native American travel, which required crews to be sensitive to any artifacts they encountered during construction.
Dome Technology’s team met the logistical and aesthetic challenges while providing a one-of-a-kind facility.
“With three openings more than 100 feet wide, its elliptical shape, and low profile, this dome makes a wonderful fit for the desert landscape and the first-ever (commercial) spaceport,” said Dome Technology project manager Daren Wheeler. “The customer requested that whatever the finishes were on the exterior, that it blended with the environment. The tile really does look like the desert floor.”
- Posted on
- by Rebecca Pyper
When planning or improving a coal storage and handling facility, it’s important to consider first things first. Domes are an […]
When planning or improving a coal storage and handling facility, it’s important to consider first things first. Domes are an ideal option for storage since the apex can easily support large loads from the headhouse and conveyors, and the overall system is efficiently designed for filling, storage and reclaim systems. But these features all come standard. Customizing the structure and its systems is the key to optimal function.
Here are a few important categories to consider for a one-of-a-kind, high-production facility:
The amount of storage and desired throughput
Storage requirements dictate everything else, from the type of storage to how often the facility will be emptied and how many tons will run through it per week or month. This is also the time to discuss anticipated growth and plan for that too.
Coal projects often start with a look at the end and work backwards. For ADM in Clinton, Iowa, the size of the dome was driven by their desired burn rate. As a cogeneration power plant, ADM needed to maintain a constant 60,000 short tons of coal on site. So a 298-foot dome was planned and built to accommodate those needs. Later, in Columbus, Ohio, ADM contracted another dome to be built, this one 300 feet in diameter with the same storage capacity to get a similar amount of kilowatts.
The type of coal being stored
With bituminous coal, stacking and reclaim options are expansive. From front-end loader to stacker reclaimer or drag chain, coal producers can be selective, balancing low cost with sophistication. Dome Technology’s team has seen rotary plows with cone-shaped piles as an effective reclaim option, but another effective choice is tall domes with a high percentage of live reclaim.
With subbituminous coal, requirements are stricter. Based on volatility, customers must decide how they’ll maintain access to the pile for putting out potential fires and hot spots.
A doughnut-shaped pile is a good option for storing subbituminous coal. The pile is placed and reclaimed using a stacker reclaimer, a model that allows access to the pile and can work particularly well when the cleanout happens every couple weeks. A monitoring system on the inbound conveyor is necessary so hot coal is rejected before being placed in the storage.
A kidney-shaped pile can also work well. The stacker creates a pile that tapers off on the side, and the filling arm’s swing is 230 to 250 degrees. This shape provides ample access to the pile, so while it might not make the most of a dome’s capacity, it does provide peace of mind and safety when managing a volatile product like coal.
Site restrictions
Although a round dome is predictable and popular, elliptical-shaped domes work well on narrow sites. For one recent project, Dome Technology proposed an elliptical-shaped dome located on a port to reach the desired capacity and fit the available space. The dome would be 300 feet long and 200 feet wide and 80 feet from the ground level to the top of the dome. Three filling points would line the top of the dome shell with a drag chain and front-end loader providing reclaim. Since an elliptical dome like this isn’t perfectly round and therefore won’t distribute loads evenly, engineers design the structure to support anticipated loads.
Dome Technology typically employs a design-build method for the entire project, but companies can also request support in specific portions of projects. With more than 40 years in the dome-building industry and a portfolio of completed projects to match, the team can provide the design and installation of the mechanical systems required for bulk storage, from equipment on the inbound side to reclaim systems and throughput speed. When every element is planned with the others in mind, the result is a seamless, highly efficient system.
By Rebecca Long Pyper for Dome Technology
Editor’s note: The preceding was published in the February 2021 issue of Dry Cargo International.
- Posted on
- by Rebecca Pyper
Structural steel is a major component of any bulk-storage project, and with a fabrication shop on the same campus as […]
Structural steel is a major component of any bulk-storage project, and with a fabrication shop on the same campus as corporate construction headquarters, it’s easy for Dome Technology engineers and construction managers to work closely with team members who build features like stair towers, work towers, conveyor supports, handrails, and walkways.
“We’re tied closely to the dome, so we know what (customers) want, and we know how everything interfaces,” said Dome Technology shop operations manager Kirby Sheldon. “We’ll see problems other fabricators won’t see.”
Dome Technology recently wrapped up a fabrication project for Savannah Bulk Terminal, and “we are in the middle of several of our turnkey projects where we are doing all the fabrication for the project,” Dome Technology Vice President of Operations Dan South said.
A dozen employees work in the Dome Technology shop. Work includes welding, design, fabrication, pipe fitting, stair towers and handrails, conveyors, chute work, conventional buildings, and steel buildings.
Recently a few structural-steel projects have received attention in the news. For McInnis Cement’s Rhode Island facility, Dome Technology installed a truck lane, steel storage silo, structural-steel convey piping support, and stair platform with connecting structural-steel bridge to the dome apex. Shortly thereafter, McInnis hired Dome Technology to build an additional truck bay for its Bronx facility, including piping and structural-steel installation. Within 130 days the team executed all structural and millwright work at the Bronx, and operations at the facility were not interrupted during construction.