A minitube blanket for landfill gas collection and containment Minitube blanket description and installation FIGURE 2 Minitube blanket description FIGURE 3 Connection of the minitube blanket to the collector pipe 18 Geosynthetics | August September 2019 As this technology differs from more common solutions, it is important to first describe the product to be used. The minitube blanket is comprised of 1-inch (25-mm) corrugated polypropylene perforated pipes spaced on 10-inch (250mm) centers between two nonwoven geotextile layers (Figure 2). Tubular drainage geocomposites have been used in landfill applications around the world for more than 25 years. They are compliant with ASTM D7931, Standard Guide for Specifying Drainage Geocomposites, and are defined as multilinear drainage geocomposites in ASTM D4439, Standard Terminology for Geosynthetics. An important characteristic of tubular drainage geocomposites is that they maintain their transmissivity under significant normal stresses (Saunier et al. 2010) because they don't experience geotextile intrusion into the drainage conduits (the minitubes) and no creep in compression of the minitubes when confined. Therefore, for most applications, the applied combined reduction factors for tubular drainage geocomposites are almost half of those applied to standard geonet geocomposites (Maier and Fourmont 2013). A roll is typically 13-feet (4-m) wide and it replaces a 3-foot (0.9-m) wide × 6.5-foot (2-m) deep trench filled with aggregates surrounding a 6-inch (150mm) diameter perforated high-density polyethylene (HDPE) pipe. Common spacing between horizontal LFG collectors is about 50-100 feet (15-30 m) horizontally and 30-40 feet (9-12 m) vertically. This is a significant loss of airspace and waste disposal tipping fees during the lifetime of a landfill. The minitube blanket is unrolled directly on the waste and connected to a collector pipe using connectors specially