Tailings management has become an essential aspect of modern mining operations due to the environmental risks associated with improper handling and storage of mine residues. One of the key components in constructing safe and sustainable tailings storage facilities (TSFs) is the use of geomembrane liners, which act as impermeable barriers to prevent the seepage of hazardous substances into the environment. Among the various geomembrane specifications, the 1mm high-density polyethylene (HDPE) geomembrane has been widely applied due to its balance of performance, cost, and ease of installation. This article explores the application of 1mm geomembrane in tailings storage facilities, focusing on its properties, installation considerations, advantages, limitations, and real-world case applications.

Tailings are the by-products of mineral processing, often containing fine particles and chemical residues. The storage of tailings poses significant environmental risks, including groundwater contamination, dam failure, and soil degradation. To mitigate these risks, tailings storage facilities are typically designed with multiple layers of protective materials, with geomembranes serving as the primary impermeable layer.

HDPE geomembranes, in particular, have gained widespread use due to their chemical resistance, UV stability, and mechanical strength. The 1mm HDPE geomembrane is a commonly selected thickness for various tailings management applications where moderate mechanical stress is anticipated, and cost optimization is a concern.

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Properties of 1mm HDPE Geomembrane

HDPE geomembranes of 1mm thickness exhibit several properties that make them suitable for tailings storage applications:

Chemical Resistance: HDPE geomembranes are highly resistant to a wide range of chemicals, including acids, alkalis, salts, and organic compounds commonly present in tailings.
Impermeability: With a permeability coefficient as low as 1.0×10^-14 cm/s, the 1mm geomembrane provides an effective barrier against liquid and gas migration.
UV Resistance: HDPE has inherent UV resistance, allowing the geomembrane to maintain performance even when exposed to sunlight during installation and operation phases.
Tensile Strength and Elongation: The material has a tensile strength typically exceeding 20 MPa and elongation at break over 700%, providing flexibility and resistance to punctures and tears.
Durability: Under standard conditions, the service life of HDPE geomembrane can exceed 50 years, making it suitable for long-term tailings storage facilities.

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Application of 1mm Geomembrane in Tailings Storage

The 1mm HDPE geomembrane is applied as part of the composite liner system in tailings dams and storage ponds. Its primary functions include:

Seepage Control: The geomembrane serves as the main barrier preventing leachate and contaminated water from infiltrating the surrounding soil and groundwater.
Erosion Protection: The geomembrane reduces the risk of internal erosion by preventing water movement within the tailings mass.
Environmental Protection: By containing tailings and process water, the geomembrane helps to comply with environmental regulations and minimizes the ecological footprint of mining operations.

4. Installation Considerations

Proper installation is critical to the performance of the geomembrane liner. The following key aspects should be considered:

Subgrade Preparation: The subgrade must be properly leveled, compacted, and free of sharp objects to avoid puncturing the liner.
Seaming and Welding: The geomembrane sheets are overlapped and welded using hot wedge or extrusion welding methods. The quality of welds should be tested using non-destructive methods like air pressure testing or vacuum box testing.
Anchoring: The geomembrane must be securely anchored in perimeter trenches to prevent movement due to wind or fluid pressures.
Protection Layers: Often, a layer of geotextile is placed above and/or below the geomembrane to provide cushioning and prevent mechanical damage during placement of tailings or cover materials.
Quality Control: Comprehensive quality control measures, including visual inspection, seam testing, and documentation, should be implemented throughout the installation process.

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Advantages of 1mm Geomembrane in Tailings Applications

The use of 1mm geomembrane offers several advantages:

Cost-effectiveness: Compared to thicker liners, 1mm geomembrane provides adequate performance in many tailings applications while reducing material and transportation costs.
Ease of Handling: The lighter weight of 1mm sheets simplifies handling, deployment, and installation, particularly in remote or difficult terrains.
Flexibility: The 1mm thickness provides a balance between flexibility and mechanical strength, accommodating minor subgrade settlement without cracking.
Compatibility with Composite Liners: In many cases, 1mm geomembrane is used in conjunction with compacted clay liners (CCLs) or geosynthetic clay liners (GCLs) to enhance barrier performance.

Limitations and Challenges

Despite its advantages, the use of 1mm geomembrane also presents some limitations:

Lower Puncture Resistance: Compared to thicker geomembranes (e.g., 1.5mm or 2mm), the 1mm geomembrane is more susceptible to punctures, especially from angular stones or tailings materials.
Higher Risk of Installation Damage: The thinner liner requires more careful handling and strict quality control during installation to avoid damage.
Site-specific Suitability: In high-load or aggressive chemical environments, a thicker geomembrane might be necessary to ensure long-term performance.

Application in a Gold Mine Tailings Facility

In a gold mine located in a mountainous region of Southeast Asia, a 1mm HDPE geomembrane was selected for the lining of a tailings storage pond. The design incorporated a composite liner system consisting of:

Compacted clay layer (0.5m thickness)
1mm HDPE geomembrane
Non-woven geotextile protection layer (above and below the geomembrane)

The selection of 1mm geomembrane was driven by considerations of cost, transportation limitations due to remote location, and moderate loading conditions. The installation was completed within two months, with extensive quality control measures, including seam testing and leak detection surveys.

After three years of operation, monitoring data indicated no significant leakage or deformation of the liner system, demonstrating the adequacy of 1mm geomembrane in this application.

No.	Item	Unit	Index
1	Thickness	mm	0.30	0.50	0.75	1.00	1.25	1.50	2.00	2.50	3.00
2	Density	g/cm³	≧0.940
3	Tensile yield strength	N/mm	≧4	≧7	≧10	≧13	≧16	≧20	≧26	≧33	≧40
4	Tensile breaking strength	N/mm	≧6	≧10	≧15	≧20	≧25	≧30	≧40	≧50	≧60
5	Yield elongation	%	-	-	-	≧11
6	Break Elongation	%	≧600
7	Right-angle Tearing strength	N	≧34	≧56	≧84	≧115	≧140	≧170	≧225	≧280	≧340
8	Puncture strength	N	≧72	≧120	≧180	≧240	≧300	≧360	≧480	≧600	≧720
9	Carbon black content	%	2.0~3.0
10	Dispersion of carbon black	-	There is not more than one level 3 in 10 data, and level 4 and level 5 are not allowed to exist.
11	Oxidation induction time	min	≧60
12	Low temperature impact embrittlement properties	-	Pass
13	Water vapor permeability coefficient	g.cm/ (cm².s.Pa)	≦1.0*10^-13
14	Dimensional stability	%	±2.0
Note	Technical performance indicators for thickness specifications not listed in the table are required to be performed by interpolation.

The 1mm HDPE geomembrane is a practical and cost-effective solution for tailings management in many mining operations. It offers an adequate balance of impermeability, durability, and ease of installation when applied under suitable site conditions and combined with proper engineering design and quality assurance measures.

However, engineers and designers must carefully evaluate the specific conditions of each project, considering factors such as chemical composition of tailings, load pressures, climate, and site accessibility before selecting the 1mm geomembrane. When applied appropriately, the 1mm geomembrane can contribute significantly to the safe, sustainable, and environmentally responsible management of tailings storage facilities.

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1.5geomemrbane test report.pdf