Bentofix^® + X Geosynthetic clay liner

Bentofix^® + X is a Thermal Lock multicomponent geosynthetic clay liner (GCL) and geosynthetic clay barrier (GBR-C) from Naue. It combines a sodium bentonite core needle-punched between PP geotextile layers with an enhanced extrusion-coated PE layer permanently bonded to the woven carrier. The ‘+’ designation marks an advanced PE formulation with extended OIT (Oxidative Induction Time, ASTM D3895) and HPOIT (ASTM D5885) values, providing longer coating resistance against chemical attack and ageing vs. standard Bentofix^® X. Two independent sealing barriers in one product.

Pricing depends on project volume, variant (+X2, +X5F, +X10F), bentonite type (BFG, NSP) and project location. Bentofix^® + X carries a premium vs. standard Bentofix^® X due to the enhanced ‘+’ PE coating formulation. Request a project-specific quote via the contact form below or contact info@naue.com.

Both are Thermal Lock multicomponent GCLs with the same needle-punched construction, bentonite core and variant range (+X2/X2, +X5F/X5F, +X10F/X10F). The critical difference is the PE coating formulation. Bentofix^® + X uses an advanced resin and batch composition that delivers extended OIT and HPOIT values beyond the standard X coating and beyond conventional GM13 requirements. This provides measurably longer coating durability in harsh oxidative environments. For applications where standard OIT values satisfy the design, Bentofix^® X is the cost-effective choice.

+X2 has a smooth ‘+’ PE coating (200 g/m²). Use for waterproofing, pond liners, flat installations and applications where slope friction is not critical. +X5F has a structured ‘+’ coating (500 g/m², 0.4 mm nod height) providing ≥ 9 kPa interface friction at 20 kPa (ASTM D6243). Use for TSF and landfill side slopes. +X10F has a heavy structured ‘+’ coating (~1,000 g/m², ~0.9 mm nod height) providing ≥ 15 kPa interface friction for the steepest embankment slopes. All three variants are available in BFG 5300 and NSP 4000/4900 types.

OIT (ASTM D3895) and HPOIT (ASTM D5885) measure the oxidative resistance of a PE barrier coating. Once the antioxidant reserve is depleted, the PE coating begins to degrade and embrittle. In mining environments, heap leach pads, TSF with acid rock drainage and evaporation ponds in hot climates, oxidative stress is continuous. Standard PE-coated GCLs meeting GM13 minimums may not provide adequate long-term performance. Bentofix^® + X extends the OIT induction period through its unique resin and batch composition.

One square metre of Bentofix^® + X (~10 mm installed) replaces up to 400 mm of compacted clay liner. This reduces excavation volumes, clay import and transport movements. The PE coating allows a 50% reduction in cover soil thickness compared to standard GCL applications in capping, as confirmed at Stuart Landfill, Australia (100,000 m², X10F). Longer coating service life reduces the risk of liner replacement, the largest cost in mining liner systems

Bentofix^® + X carries CE marking, is produced under ISO 9001 quality management and DIN 18200 third-party monitoring. An EPD covers the Bentofix product family (EN 15804:2012+A2:2019, 2020).

Naue has published an EPD for the Bentofix^® product family covering the full lifecycle (A1 to C4).

The Thermal Lock needle-punched composite construction provides high installation damage resistance. The Thermal Lock process permanently integrates fibres into the ‘+’ PE coating, preventing delamination in hot climates confirmed by laboratory testing (300 days, 40°C, 18 kN/m²). Every roll is needle-detector tested across its full width. Tensile strength: 14/14 kN/m md/cmd (+X2, EN ISO 10319); 22/22 kN/m (+X5F BFG 5300). Static puncture: 2,500 N (+X2); 3,300 N (+X5F). Roll dimensions: 4.85 m x 40 m (194 m²). Overlaps sealed with Bentofix^® X Tape B.

Bentofix^® + X BFG 5300 rolls: 4.85 m wide x 40 m long (194 m² per roll). This is the same as Bentofix^® X. NSP type roll dimensions are the same (4.85 m x 40 m). The 30 cm overlap zone is pre-marked on the PE layer of every roll.

DIN 18200 (third-party monitoring), CE marking, ISO 9001. Testing per: EN ISO 10319 (tensile strength), EN ISO 12957-1 (internal shear strength), ASTM D6496 (peel strength), ASTM D6243 (interface friction), EN 16416 / ASTM D5887 (GCL hydraulic conductivity), EN 14150 (PE layer k), ASTM D3895 (OIT), ASTM D5885 (HPOIT). OIT and HPOIT values exceed GM13 minimum requirements.

Yes. Naue provides engineering support for mining and containment liner projects including slope stability calculations, liner system design, OIT/chemical compatibility analysis, specification preparation and installation supervision. Contact info@naue.com or submit a project request via the contact form below.

Conventional PE-coated GCLs meeting GM13 (GRI GCL3) requirements must achieve minimum OIT values at specified test conditions (ASTM D3895). Bentofix^® + X exceeds these minimum values through its unique ‘+’ resin formulation.

Yes. Bentofix^® + X is a preferred GCL solution for heap leach pad liner systems. The ‘+’ PE coating provides the oxidative resistance needed in aggressive acid leach solutions used in gold, copper and silver heap leaching. The PE coating shields the bentonite from cation exchange with saline reagents. The bentonite provides a redundant sealing function. The +X5F (≥ 9 kPa) and +X10F (≥ 15 kPa) structured surfaces deliver high friction angles for slopes where the heap loads onto the liner. Contact Naue engineering for site-specific liner system design.