18 www.coalage.com May 2017
longwall usa 2017 continued
ENTRANCE
tion of this predictive tool that can deter-
mine when individual components will
reach the end of their serviceable life.
This Extended Life Testing can realize
an additional 15,000 to 30,000 cycles out of
a roof support that was originally specified
for only 30,000 cycles depending on the
operational loading and duty cycle. This
can sometimes push capital expenditure
five to seven years into the future. To gain
detailed knowledge of the duty and cur-
rent structural competence, a represen-
tative roof support is taken out of service,
stripped and fully evaluated. The support
is then tested up to target number of life
cycles and a test protocol is developed us-
ing load cases that are tailored to replicate
the typical, actual service experienced by
the roof support to date.
A detailed report is issued indicat-
ing when components either have or will
likely reach the end of their serviceable
life. A detailed Life Cycle Management
plan is proposed allowing the planning
of future maintenance budgets with a
high level of accuracy and confidence in
the life of the supports or support com-
ponents going forward.
A powered roof support supplied in
2009 and initially tested up to 30,000 cycles
was examined with a requirement to ex-
tend the support's life to 45,000 cycles. The
support had seen 13,000 underground cy-
cles in some pretty tough conditions. It was
dismantled and visually inspected, with
all cracks and damage identified and as-