8
-or grouted in place. There are numerous ways of designing
and installing in either of these configurations, touched on
in the following sections.
Shaft Installation
Apart from sinking, shaft installations typically have been
in service or ventilation shafts, following the common sepa-
ration of production tasks and facilities from support ser-
vices such as construction and backfill. In completed shafts,
among attractions of shaft-mounted systems are access
for installation and maintenance, perhaps with space for
multiple pipe ways allowing simultaneous operation and
maintenance cycles. If the shaft is compartmented, brattice
(typically expanded metal with selective plate locations)
can be used much as with ore compartments in production
shafts.
At the collar or in a sub-collar, vacuum break and/or
pressure relief valves/conduits can be configured alongside
the pipe ways and to appropriate access locations.
Feed hoppers are arranged to accommodate both the
transfer material and the site layout and opportunities. If
they serve multiple lines, they may be gated for line selec-
tion. Gates typically are affixed to the hopper and any ori-
fice insert assembly, or the line itself if no insert is used. In a
shaft installation, the line inlet hopper itself may be fed by a
separate belt or feeder which receives the material through a
dump hopper or grizzly. That keeps potential dump upsets
removed from the shaft collar, as well as providing oppor-
tunity for metering flow into the dropline.
Principal considerations for shaft installations are the
shaft set capacity and serviceability. Sets have been designed
to support single lengths of pipe, multiple lengths, or an
entire line, as appropriate. It is prudent to design the sys-
tem to support potential malfunctions such as a full line. In
the same regard, the pipe couplings must accommodate the
required service, including shock loading from hang-ups or
line clearing.
Since slicklines have a finite life, it is prudent to design
the shaft sets for ease of pipe handling. The immediate sup-
ports typically clamp the pipe, provide a chair to support a
collar or spur(s), or a combination of both. When chairs are
used, it is advisable to field fit the pipe collars to properly
engage each individual set location in the shaft.
Repairs to transfer line segments typically are temporary,
with segment replacement being the long-term resolution.
With a collar-suspended line, typical segment replacement
entails removing segments from the bottom up until the
damaged segment(s) can be replaced. In the alternative,
raising the line (and removing segments) or lowering the
line (and adding segments) until the damaged segment(s)
is(are) accessible for replacement, which are common tech-
niques for collar-suspended borehole installations.
With lines supported at each shaft set, the specific
damaged segment(s) can be replaced without handling the
entire string. Another benefit of support at each set is to
provide adjacent support if wear through a pipe segment
progresses to damage at the immediate set as well as down-
ward along the line. Designing for robust and redundant
support capability can reduce the effects of damage to sup-
port brackets. It is not recommended to support from the
bottom and use shaft sets only for alignment. At best, that
scenario requires segment removal from the top down, but
may lead to untenable outcomes given the tendency for
lowermost segments to wear first.
As with sets in general and rigid shaft guides, the align-
ment of a slickline is more important than verticality (9).
Though Coriolis effects influence all but shallow installa-
tions, misalignment can pose great wear and disruption
to pipe service, especially if the transfer line follows a dis-
jointed path.
A related aspect of alignment is the need for smooth
pipe joints with minimal gap. The Meikle Mine basalt-
lined aggregate transfer system (1) initiated with interme-
diate suspension sets every 61 vertical meters (200 ft), with
the intent to minimize alignment difficulties. The suspen-
sion collars were bell and spigot arrangements, which pro-
vided wear locations as the falling rock impacted the bell
below. The bell liners shattered and the pipe lining imme-
diately below scoured quickly, resulting in a service life of
only 61,600 t (metric ton, 67,900 ton). The system was
reconfigured with conventional pipe joints throughout,
each length supported from a shaft set, aligned by laser, and
operated successfully, providing a consistent service life on
the order of 544,300 t (600,000 ton).
Borehole–Collar Suspended
Borehole installations avoid potential congestion at shafts
and shaft stations, and system upsets typically do not
directly impact shaft operation. A common selection is to
collar suspend the transfer line, allowing replacement with-
out having to drill a new borehole. In collar suspension,
the typical lines have threaded couplings and follow API
specifications, permitting conventional threaded handling
and placement. Alternatively, welded connections are used,
which typically entail fabricating the pipe with lifting rings
for handling and placement. Grooved or flanged couplings
require a significantly oversized borehole and casing and are
not readily compatible with tools that handle conventional
drill strings.
-or grouted in place. There are numerous ways of designing
and installing in either of these configurations, touched on
in the following sections.
Shaft Installation
Apart from sinking, shaft installations typically have been
in service or ventilation shafts, following the common sepa-
ration of production tasks and facilities from support ser-
vices such as construction and backfill. In completed shafts,
among attractions of shaft-mounted systems are access
for installation and maintenance, perhaps with space for
multiple pipe ways allowing simultaneous operation and
maintenance cycles. If the shaft is compartmented, brattice
(typically expanded metal with selective plate locations)
can be used much as with ore compartments in production
shafts.
At the collar or in a sub-collar, vacuum break and/or
pressure relief valves/conduits can be configured alongside
the pipe ways and to appropriate access locations.
Feed hoppers are arranged to accommodate both the
transfer material and the site layout and opportunities. If
they serve multiple lines, they may be gated for line selec-
tion. Gates typically are affixed to the hopper and any ori-
fice insert assembly, or the line itself if no insert is used. In a
shaft installation, the line inlet hopper itself may be fed by a
separate belt or feeder which receives the material through a
dump hopper or grizzly. That keeps potential dump upsets
removed from the shaft collar, as well as providing oppor-
tunity for metering flow into the dropline.
Principal considerations for shaft installations are the
shaft set capacity and serviceability. Sets have been designed
to support single lengths of pipe, multiple lengths, or an
entire line, as appropriate. It is prudent to design the sys-
tem to support potential malfunctions such as a full line. In
the same regard, the pipe couplings must accommodate the
required service, including shock loading from hang-ups or
line clearing.
Since slicklines have a finite life, it is prudent to design
the shaft sets for ease of pipe handling. The immediate sup-
ports typically clamp the pipe, provide a chair to support a
collar or spur(s), or a combination of both. When chairs are
used, it is advisable to field fit the pipe collars to properly
engage each individual set location in the shaft.
Repairs to transfer line segments typically are temporary,
with segment replacement being the long-term resolution.
With a collar-suspended line, typical segment replacement
entails removing segments from the bottom up until the
damaged segment(s) can be replaced. In the alternative,
raising the line (and removing segments) or lowering the
line (and adding segments) until the damaged segment(s)
is(are) accessible for replacement, which are common tech-
niques for collar-suspended borehole installations.
With lines supported at each shaft set, the specific
damaged segment(s) can be replaced without handling the
entire string. Another benefit of support at each set is to
provide adjacent support if wear through a pipe segment
progresses to damage at the immediate set as well as down-
ward along the line. Designing for robust and redundant
support capability can reduce the effects of damage to sup-
port brackets. It is not recommended to support from the
bottom and use shaft sets only for alignment. At best, that
scenario requires segment removal from the top down, but
may lead to untenable outcomes given the tendency for
lowermost segments to wear first.
As with sets in general and rigid shaft guides, the align-
ment of a slickline is more important than verticality (9).
Though Coriolis effects influence all but shallow installa-
tions, misalignment can pose great wear and disruption
to pipe service, especially if the transfer line follows a dis-
jointed path.
A related aspect of alignment is the need for smooth
pipe joints with minimal gap. The Meikle Mine basalt-
lined aggregate transfer system (1) initiated with interme-
diate suspension sets every 61 vertical meters (200 ft), with
the intent to minimize alignment difficulties. The suspen-
sion collars were bell and spigot arrangements, which pro-
vided wear locations as the falling rock impacted the bell
below. The bell liners shattered and the pipe lining imme-
diately below scoured quickly, resulting in a service life of
only 61,600 t (metric ton, 67,900 ton). The system was
reconfigured with conventional pipe joints throughout,
each length supported from a shaft set, aligned by laser, and
operated successfully, providing a consistent service life on
the order of 544,300 t (600,000 ton).
Borehole–Collar Suspended
Borehole installations avoid potential congestion at shafts
and shaft stations, and system upsets typically do not
directly impact shaft operation. A common selection is to
collar suspend the transfer line, allowing replacement with-
out having to drill a new borehole. In collar suspension,
the typical lines have threaded couplings and follow API
specifications, permitting conventional threaded handling
and placement. Alternatively, welded connections are used,
which typically entail fabricating the pipe with lifting rings
for handling and placement. Grooved or flanged couplings
require a significantly oversized borehole and casing and are
not readily compatible with tools that handle conventional
drill strings.