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Numerical modelling of blast and gravity flow in SLC mines – a prestudy

Publicerad: 13 november 2018
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Sublevel caving (SLC) is a mass mining method which is applied in LKAB's mines in Kiruna and Malmberget. The major disadvantage of SLC is the high dilution of the ore by waste and ore losses. A major factor influencing this dilution and ore loss is the flow behavior of the ore and waste material. Blasting has been identified as the initial, but also as the major impact upon primary fragmentation and later material flow characteristics. How ever, the mechanism of the blasting in confined conditions and the gravity flow of blasted and caved material is not well
understood so far.

The purpose of this pre-study is to develop a numerical modelling method to model both blast fragmentation and the later gravity flow in SLC mines in one model with one solver. In the numerical model, a bonded particle model w ill be used to model an intact ore body to be blasted and a loose particle model w ill be used to model the caved waste rock which provides a confined environment for the ore body to be blasted. The remaining ore body w ill be modelled with a finite element model to investigate the blast-induced damage in the remaining ore body. The detonation of explosives w ill be modelled with a particle blast model which is a new method to model detonation based on a particle method.

The successful completion of this research would result in an innovative methodology for assessing blast performance and gravity flow in SLC mines. The numerical model can be used to investigate the effects of variations such as SLC layout, ring design and blast parameters on the blast fragmentation and the gravity flow . The model and the know ledge gained from
the project may be applied to optimize blast layout as ring design and blast parameters and ultimately improve SLC performance through a full-scale project.

Contact person: Dr Changping Yi , changping.yi@ltu.se