The valuable component can be only a small proportion of the ore, at times less than one percent. The rest is viewed as waste that must be disposed of. However this waste has had energy applied to reduce it in size, which can represent a value. The mining industry operates at large scale, so the amount of waste to be used can be very large.
Ceramic building materials
A literature review was made on the use of various types of industrial waste for producing ceramic building materials, such as brick, stone and tile. Read more details here.
Mining waste as a cementitious binder
Certain sorts of mining waste can be suitable for use as a binding additive in concrete. This can give a high volume consumption of mine waste as well as potentially reduce the carbon footprint of the cement production. Read more here.
Re-processing of former mine waste
The advancement of processing technologies has increased the proportion of valuable components that are recovered fro the ore. A consequence of this is that some of the historical tailings deposits from earlier activity can contain economical quantities of valuable components. Re-processing the mine waste tailings with modern process technology can yield more valuable products as well as stabilise the residue or make it more suitable for other purposes.
Low grade ore heap leaching
Mining waste can be defined as when the remaining valuable components in the ore are present in too low concentrations to be economically recoverable by traditional processing. One alternative for such low grade ores is to leach the valuable components using chemicals or microbes. This has been performed at full-scale in cold climate by Terrafame (formerly Talivaara) in Finland, for an ore that was not possible to process by traditional technologies. Read more about heap leaching here.
Recovery of Rare Earth Minerals from waste
This has become an active topic during the course of the SEESIMA project. NW Russia has long experience of the extraction of Rare Earth Minerals from apatite. LKAB in Sweden has been developing plans for re-processing of the mining waste from their iron ore processing,
Functional titanium compounds
A waste product from the processing of apatite-nepheline ores from Khibiny in NW Russia has been studied for the production of useful titanium-containing products. These products have been shown to have a wide range of applications such as photocatalysts or electronic components. It was also possible to be used for removing heavy metals from wastewater. Read more about these developments here
Reduction of iron ore
Emissions from steel production are significant on a global basis, particularly CO2 emissions from the reduction of iron oxide ore. LKAB is developing a process based on using hydrogen rather than coal to achieve this, which will dramatically reduce the environmental impact. SINTEF Narvik has earlier collaborated with LKAB on a PhD study examining the different ratios of hydrogen and carbon i the reduction process, and has continued to work on developing concepts for implementing this in Norway. Read more here.