The restricted space in underground work sites
in mining and tunnelling always entails the potential of
collisions between men and machinery. Despite work
rules and safety training, accidents of this category are
still too frequent and therefore technical safety systems to
avoid such collisions have been asked for and developed.
In the United States of America and South Africa a rising
number of such proximity detection systems are in operation and allow a first review of the impact on safety
of miners. This article presents the state of the art and
based on the existing operational experience some of the
necessary further developments in this field.