Physical and mechanical properties of differently composed mixtures used for a stabilised backfill

Authors: F. Plewa, J. Sobota

Heavy industry in Poland generates about 120 million tonnes of waste per year.

Most of this waste is related to hard coal mining and thermal power generation. Utilisation of those wastes within mining technologies remains one of most effective and valuable method of their disposal.

Fly ashes and tailings can be applied in many technological processes accompanying coal mining, among others, the back--filling of voids, isolation of caving zones, strengthening of rock mass, etc. To achieve the expected effects the slurries must meet certain conditions.

These are described by a number of parameters, which determine their behaviour as fluids while they are being transported and then their solidifying characteristics and their mechanical properties as a solid bodies.

The paper presents a range of parameter measurements considered important from the point of view of their application in mining technologies - fluidity, setting time, load capacity, compressibility, and compressive strength of slurries made in different proportions of fly ashes from two power stations, also flotation tailings, and the use of cement as a binder.

All proportions of slurry constituents are expressed in terms of mass.