Background In the European context, mining and quarrying waste is a significant source of pollution and general environmental degradation of soil, in particular of freshwater ecosystems that can also lead to potential health problems for animals and humans. Mining operations also produce variable amounts of waste rock and tailings material. More than 400 million tonnes of waste from the extractive industries is produced each year in the EU. In Finland alone 50 million tonnes of mining waste is produced each year, as well as 15-20 million tonnes/yr of tailings material. Although some of the mining waste can be replaced as backfill during mining or used elsewhere, large quantities of waste rock and tailings are still commonly stockpiled around mine sites. For instance, in Finland alone, there are currently 47 tailings impoundments, and some 40 mines and quarries. Remediation of Finnish tailings heaps consumes hundreds of millions tonnes of natural aggregates, and enormous amounts of commercial sealing products, which together generate greenhouse gas emissions The creation of mining waste storage facilities uses a considerable amount of materials, most of them originating from non-renewable and ultimately finite resources, such as eskers, rocks and top soils. In addition to primary aggregates, imported commercial oil-based geosynthetics (bentonites, geomembranes) are used. The potential pollution hazards associated with storage of the tailings slurry vary with different mining operations. The tailings disposal area is usually a pond that has been created by the construction of a dyke or a damn to retain the tailings slurry. The overall environmental performance of the contemporary sealing system could be drastically improved, if these materials could be substituted with industrial by-products and waste material combinations and new intelligent buffering systems developed. Objectives The project aims to demonstrate a technically and environmentally feasible alternative for remediating mine sites without using commercial sealing products such as bentonitemattes and geosynthetic geomembranes. The project is expected to use waste material to carry out the remediation processes with help from an innovative technology based on chemical-and physical stabilisation effects, through which material combinations can be transformed into valuable sealing layer materials. Physical stabilisation means that the material will become geotechnically stronger. Specifically the project will oxidate sulphate minerals leading to acid rock drainage (ARD). The project will demonstrate the rich Ca-content, alkaline characteristics, low carbon footprint and application potential of the new method. The project also aims to reduce the need for commercial oil-based products and preserve primary aggregates and raw materials. Outcomes are intended to protect landscapes, forests and local forestry livelihoods, wildlife, plants, recreation and other nature values. Use of lifecycle assessment (LCA) and lifecycle costing (LCC) tools will help to verify the technology’s environmental credentials. Expected results: The project will: Produce at least three practical civil-engineering applications and demonstration pilots to show how new types of industrial by-product combinations can be successfully used in mine remediation structures, without compromising overall environmental protection targets; and Deliver knowledge, information, and methodological guidance for key target groups via active dissemination events and effective dissemination tools.