Mining the opportunity

Whether aboveground or below, excavating minerals, precious gems or coal, all mining operations face similar challenges: mitigating impact to the land while the mine is active, restoring it when mining is no longer occurring and keeping workers as safe as possible both short-and long-term.

These are not new issues. But as mining operations undergo greater public and government scrutiny, and as more regulations and laws have been established outlining the industry’s responsibility, there is growing pressure to find workable, effective solutions addressing those concerns. Specialty fabricators have stepped up, playing a significant role in this effort, and several textile-based products are helping the mining industry meet these objectives. 

Filling the void

Colossal in size, the mobile processing unit (MPU) is deployed for dry-mining operations. Sitting adjacent to an active mining area, ore/mineral sands are pushed into the unit’s hopper via front-end loaders, trucks, bulldozers and similar types of equipment. The MPU is semimobile, remaining in place with its tracks lifted off the ground for about six weeks at a time.

While the tracks are lifted and the machine is in operation, sand, dirt and other debris collects around, on and under the tracks. This must be removed and the ground returned to its compacted state before the tracks can be lowered and the MPU moved to another area. Because this clearing typically happens manually—for example, by workers outfitted with shovels—it’s a labor-intensive endeavor and not without risk.

One shoveling team at a zircon mining operation in South Australia wondered if there was a way to prevent the accumulation of debris via an inflatable bladder, sparking another team at that operation to draw up a design. With that in hand, they approached Giant Inflatables Industrial about turning it from concept to reality.

Located in Melbourne, Giant Inflatables devises “uncomplicated inflatable powered solutions for complex industrial challenges,” including temporary shelters for abrasive blasting and workshops, flood protection/coffer damming, personnel/debris fall protection and plugging/void-filling of ducts, tunnels and pipes, says David Abramowitch, technical director. Various textiles are deployed for these purposes, including PVC-coated nylon, PVC-coated polyester, TPU aliphatic PVC alloy and PU-coated Oxford-bag materials.

Responding to that inquiry, Giant Inflatables created the MPU Track Clearance Maintenance Filler, a void-filling cushion consisting of a PVC-coated bladder encased in a heavy-duty, UV-resistant, PU-coated Oxford-bag cloth envelope.

“The uninflated cushion is located under the track when the [MPU] is set in place and the track is lifted off the ground to stabilize and anchor the machine. [It] is designed to fill the void under the track to stop soil from filling that space. When the track is lifted, the cushion is inflated to fill the gap,” says Abramowitch.

Multiple cushions might be deployed, depending on their weight. Fully deflating them upon removal isn’t required, saving time when they’re reinstalled once the MPU is relocated.

Abramowitch foresees the industry embracing inflatable solutions as vehicles for innovation and change but also cautions that regulations and certifications are increasingly important when it comes to design approval. “This means our suppliers need to have detailed specifications for the materials they supply as well as all the flame-retardant testing certificates and tests complying to the very stringent Australian standards, which are sometimes higher than EU standards,” he explains.

Ventilating underground

Headquartered in Mexicali, Mexico (U.S. headquarters are in Calexico, Calif.), Plastic Fabric Solutions by Megaplast® manufactures PVC-coated polyester fabrics and roll goods for markets that include construction, agriculture, industrial and mining.

For the mining industry, Megaplast offers flexible mining ventilation air ducts to deliver fresh airflow to underground mine crews and to expel contaminated air and offers brattice and curtains that create partitions to direct ventilation in underground mines, says Rocio Hernández Peralta, marketing chief.

The company provides three models of air ducts—lay-flat, spiral and oval—constructed from high-tenacity, PVC-coated polyester fabric that meets Mine Safety and Health Administration (MSHA) requirements, says Peralta, describing this fire-retardant fabric as highly resistant to abrasion and tearing because of its ripstop weave. The ducts are available in the various lengths and diameters used in underground mines as well as in thicker, heavier and tougher fabric for high-pressure requirements, also carrying MSHA certification.

For Plastic Fabric Solutions, lay-flat ducts represent 50% of sales in Mexico, says Peralta. Oval models, which create more space within a smaller tunnel, represent 40% of sales. Spiral ducts, designed with steel spirals for easier handling under high-pressure working conditions, comprise the remainder. Ducts are available with or without antistatic performance. “The buildup of static electricity in ventilation ducts can create sparks, posing an explosion risk in mining environments where flammable gases may be present,” she says, explaining the need for this additive. “Static electricity can damage the sensitive electronic equipment used in mines, such as monitoring and control systems.”

Brattice and curtains can be made with any fabric the customer needs (with or without MSHA materials) and can be customized by height, length, fabric weight, tear resistance, edge reinforcement, wall attachment and hanging setup. They also are available with the antistatic additive.

Currently, the company’s ventilation ducts are present in more than 40% of Mexico’s underground mines. “Our aim this year is to participate in the United States market,” says Peralta. “There is a significant opportunity for us in the United States markets, where we hope to grow along with the demand.”

Controlling erosion

Whether during or after mining activities, the need for slope erosion control is constant, heightening the awareness and use of rolled erosion control products (RECPs), says Kurt Kelsey, director of the earth science division of the American Excelsior Company (AEC). Headquartered in Arlington, Texas, AEC manufactures and distributes products for packaging, cushioning, engineered foam specialties and erosion control, and others. Among the markets served by the division are landfills, energy, commercial/residential development, the Department of Transportation and mines.

The 1977 Surface Mine Reclamation Control Act, a federal law regulating the environmental impacts of the U.S. coal mining industry for active and reclaimed/abandoned mines, has also increased the demand for RECPs, says Kelsey.

“RECPs contain physical bonds from stitching, weaving and/or netting that provide tensile important for longer slopes, human and wildlife foot traffic areas, and all other areas and conditions where chemical bonds are not sufficient,” he explains. “RECP functional longevities range from a few months, with the quickest-degrading erosion control blankets (ECBs), to turf reinforcement mats (TRMs) that are not intended to degrade.”

Kelsey is also president/chairman of the Erosion Control Technology Council (ECTC). Headquartered in St. Paul, Minn., its “diverse membership” positions the ECTC to help educate engineers, contractors and regulators on effective erosion and sediment control practices while also promoting the use of RECPs and sediment retention fiber rolls (in addition to other tools/strategies) to combat the “cumulative and detrimental” impacts of erosion at mines, he says.

Although there are many types of mines and varying challenges, among the most common issues RECPs can help mitigate are slope erosion and stabilization. Another concern is moving water from one part of the mining operation to another without causing excessive erosion, which RECPs also can address.

“ECBs and TRMs are both suitable options depending on the design requirements and how long the RECP needs to last,” says Kelsey. “TRMs verified to meet design requirements have been used successfully to replace rock riprap down chutes at some mines. Additionally, TRMs are utilized to reinforce vegetation in ditches next to haul roads at mining operations.”

Kelsey says ECTC has worked with the mining industry providing successful solutions to mining sites “for decades,” while also helping to restore land in a way that meets or exceeds the requirements of the 1977 act. Kelsey describes demand as “trending flat to up.” As education around RECPs has improved and their benefits to mines have become better known, he expects their use to increase. 

Pamela Mills-Senn is a freelance writer based in Seal Beach, Calif.