An
open cast mine on the West Coast of the South Island of New Zealand proposes to
remove up to 30 m of overburden to access an ore body neighbouring National
Reserve land. Part of the conditions of the mining permit is that no material
above natural discharge levels may be released over the Mining Lease boundary
onto the adjacent land. In order to meet this requirement, the client has
contracted the design and installation of over 2.6 km of high energy dynamic
rockfall control barriers. This paper describes how the rockfall hazards were
assessed and the rockfall barriers dimensioned. The design involved 2D modelling
of over 3000 simulations.

Modelling parameters
were calibrated during field trials at a purpose built section of barrier. The
resultant energies ranged from 500 to 3000 kJ. The construction phase of the
project involved the drilling, anchoring, and installation of certified barriers
up to 7 m high in a remote and inhospitable climate with limited machinery
access. By exploring best practice in this specialized field of engineering, a
novel rockfall hazard mitigation solution was identified.