Building standing support and sealing off worked-out areas of an underground coal mine is some of the most consequence-heavy construction work in the industry, and it happens in exactly the places where people would rather not be. Goaf areas, the collapsed zones left behind a longwall face, continue generating gas long after the coal has been extracted. Ventilation seals have to hold that gas back reliably, for years, in an environment where a poorly built seal or a slow-curing structure isn’t just a quality defect. It’s a gas migration risk in a live underground coal mine.
For decades, the standard approach was to build these structures the same way you’d build anything underground: get materials and people into the roadway, and construct in place. Jennchem’s argument, developed first in the United States and brought to Australia in 2012, is that this approach puts people closer to elevated-risk ground for longer than necessary, and that pumping the material from the surface instead changes the safety equation as much as the productivity one.
Why the Traditional Method Adds Risk
Standing support, cribs, chocks, and pillars that hold up roof in specific zones of a mine, and ventilation seals both have to be built to precise specifications, in confined underground spaces, often adjacent to areas where gas concentrations are elevated or roof conditions are already compromised. The longer that work takes, and the more personnel and equipment movement it requires underground, the longer the exposure window stays open.
Ventilation seals carry an additional constraint. A seal that takes weeks to cure to its rated strength leaves a mine operating around an incomplete barrier for that entire period, monitoring gas levels around a structure that hasn’t yet reached the specification it was designed to. Longwall coal mining in Australia, concentrated in the coal basins of New South Wales and Queensland at depths often between 200 and 600 metres, doesn’t allow much tolerance for that kind of extended uncertainty.
Pumping From the Surface Instead of Building Underground
Jennchem’s surface-to-seam system pumps standing support and sealing material from surface equipment directly to the underground location, overland to both the maingate and tailgate from a single position. That single detail matters more than it sounds. It means one surface setup can service an entire longwall’s applications, ventilation seals, standing support, break-off standing support, and tailgate standing support, without relocating equipment or personnel underground between jobs.
The pumpable crib system that resulted from this approach has installed more than 17,000 cribs in Australian underground coal mines since 2015, at install rates exceeding eight cribs per hour. That speed isn’t just an efficiency number. Every hour removed from a standing support installation is an hour of reduced exposure for the people who would otherwise be building it in place.
The same logic applies to Jennchem’s ventilation seals. The company installs 20 psi longwall seals alongside 50 psi and 120 psi final seals using the same surface-based pumping infrastructure as its crib system, which means a site isn’t running separate crews and separate equipment for standing support versus sealing work. J-SEAL, the company’s foaming cement product for permanent ventilation seals, is built around rapid strength gain, reaching seal approval specifications in days rather than the weeks a conventional cementitious seal might require. A seal that reaches its rated strength in days rather than weeks closes the uncertainty window faster, which is the entire point of the exercise.
What a Decade of Installations Without a Lost Time Injury Actually Signals
Jennchem Australia operates under an accredited ISO 45001:2018 safety management system covering its complete underground and surface operations, and the company has recorded no lost time injuries since its Australian operations began. In an industry segment defined by underground confined space work, gas exposure risk, and heavy pumping equipment, a safety record like that isn’t incidental. It’s a direct consequence of the operating model: less time spent building structures in place, more of the process managed from controlled surface positions.
That record also reflects something about how the company has scaled. Ten years of continuous underground and surface operations, expanding from standing support into the full range of rated and non-rated ventilation control devices, without a lost-time incident, suggests a system that holds up under sustained operational pressure rather than one that looks good on a single project.
Reframing the Procurement Decision
For a mine planning longwall recovery, goaf sealing, or standing support work, the choice of contractor isn’t only about unit cost per crib or seal. It’s about how much underground exposure time the chosen method requires, and how quickly a seal reaches the strength it needs to actually do its job. Jennchem’s surface-pumped model was built around minimising both, and the installation numbers and safety record behind it are the evidence that the approach holds up at scale.
Image Credit: Jennchem
