RDI projects


Project Information
NameCompetence development for mine backfilling technologies
ContactVille Matikka
DescriptionRequirements for environmental management in mining have increased together with increasing demand of mined commodities. The mining industry has for some time now trended towards nearly invisible, low carbon, and low impact projects. Mineral processing residues piled in above-ground dammed facilities are one of the major challenges for environmental management at mines. These large facilities are often visible for long distances and increase the spatial footprint of mines. The facilities can also cause environmental deterioration due to dusting or contaminated waters seeping from the piles. Finely ground rock material exposed to atmospheric conditions starts to weather and, if it contains sulfide minerals, may produce low pH metal-laden waters. There are also examples around the world of tailings dam failures.

Placing some of the mineral processing tailings underground helps in reducing the need of above-ground tailings management facilities. Cemented backfill can even be designed for strengths that provide geotechnical advantages. For instance, backfilling may reduce subsidence or allow designing smaller pillars so that more of the ore can be safely mined. Placing the wastes underground and using various binders may help in controlling the oxidation of the tailings materials better than in above-ground facilities, provided that the properties of the backfill are known in detail.

The KOVE-PRO project is based on collaboration between the Savonia University of Applied Sciences and the Geological Survey of Finland (GTK). It combines Savonia’s activities in concrete technology and water technology with GTK expertise in mineral processing, mineralogy, and environmental management for the mining industry. The project develops solutions for low impact, low footprint mining by developing expertise in cemented paste backfilling. This allows placing a large part of mineral processing tailings back underground into mined-out cavities.
There is a need for this expertise in Finland due to the increasing use of backfilling in mining.

The detailed aims for the project are:
• Develop low-carbon binder recipes in which the use of cement has been reduced through utilizing slags and ashes
from other industries and the energy sector
• To develop methods for making test blocks and test their technical properties
• To develop methods for chemical testing, based on test blocks, of the long term performance of the CPB
• To develop the use of computed x-ray tomography in both mechanical and chemical testing
• To develop the use of automated mineralogy in CPB testing
• To provide training for the mining and consulting professionals on the utilization of the results
• To provide materials for training of engineers on CPB at Savonia UAS

The work has been divided into seven work packages that cover the process chain from the production of tailings to making test blocks and using them for testing:

WP1: Characteristics of tailings materials to be used in CPB
WP2: Water management and development of dewatering methods
WP3: Low carbon binder recipes
WP4: Geotechnical testing
WP5: Environmental properties and long-term performance
WP6: Computed tomography in testing
WP7: Dissemination, management, business models
Funded byEAKR Flat Rate 2014-2020