Materials for stronger ventilation tubing for underground use in hardrock mines were developed. The new material composites were evaluated in characteristics and compared with presently used materials on tear, tensile, puncture, and flammability properties. Based on cost versus performance data, a polyester film bonded to a polyester fabric was selected for field testing. Ventilation tubing fabricated from the selected material was field tested in two underground uranium mines for 4-month periods. The tests indicated that the new composite showed an increase in useful life in the majority of applications. However, the cost performance ratio was not sufficiently improved to warrant commercialization of the product. Improved methods of repairing inflated ventilation tubing were investigated and developed. Repair kits based on adhesives, pressure-sensitive tapes, and mechanical means were evaluated. Plier staplers and patch systems based on pressure-sensitive adhesive proved to be functional.