Caving is the lowest cost underground mining method, provided that
drawpoint spacing, drawpoint size and ore handling facilities are designed
to suit the caved material and that the drawpoint horizon can be
maintained for the draw life. In the near future several open pit mines that
produce in excess of 50 000 tons per day will have to examine the
feasibility of converting to low cost, large scale underground operations.
Several other large scale, low grade underground operations will
experience major changes in their mining environments as large
dropdowns are implemented. These changes demand a more realistic approach to mine planning than
has occurred in the past, where existing operations have been projected to
increased depths with little consideration of the change in mining
environment that will occur. As economics force the consideration of
underground mining of large, competent orebodies by low cost methods,
the role of cave mining will have to be defined. In the past caving has
generally been considered for rock masses that cave and fragment readily.
The ability to define cavability and fragmentation, the availability of
large, robust LHDs, a better understanding of draw control requirements,
improved drilling equipment for secondary blasting and reliable cost data
have shown that competent orebodies with coarse fragmentation can be
exploited by cave mining at a much lower cost than with drill and blast
Methods.